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The effect of an exogenous fibrolytic enzyme on forage digestibility parametersGoosen, Liezel 12 1900 (has links)
Thesis (MScAgric) -- Stellenbosch University, 2004. / ENGLISH ABSTRACT: The ruminant has the ability to utilize forages more efficiently than any other
production animal. The utilization of forage fibre is an important aspect of ruminant
production systems, as this is the main source of energy available to the animal. The
availability of high-fibre forage nutrients is, however, restricted by cell wall
degradability, and since low quality forages contribute a great deal to ruminant
production systems worldwide, the improvement of this degradation process is of
major economic importance.
The use of exogenous fibre degrading enzymes has been proposed as a means of
enhancing this process, with positive results being obtained from in vitro studies
incorporating exogenous enzyme preparations. Positive in vivo results with regard to
forage digestibility and other animal production parameters have consequently also
been obtained following the addition of exogenous fibre-degrading enzyme
preparations to the ruminant diet.
Two initial screening experiments were undertaken in order to identify fungal enzyme
preparations that may have a positive effect on in vitro fibre degradability. The initial
screening employed an in vitro organic matter digestibility technique, and was
successful in identifying at least six enzyme preparations displaying enhanced
digestibility results that were statistically significant. A second in vitro gas
production procedure was used to confirm results obtained from organic matter digestibility assays, as well as to increase screening capacity in order to evaluate new
enzyme preparations more time-efficiently. Statistical analysis of results obtained
from the secondary screening identified various enzyme candidates producing
promising results. Only one of these, Abo 374, proved to be statistically superior to
the control and other enzyme preparations.
A growth trial was subsequently conducted to assess the performance of this enzyme
in vivo. The trial involved individual feeding of 32 Dohne Merino ram lambs grouped
according to weights into four groups consisting of 8 lambs each. Each group
represented a specific application level of enzyme to the wheat straw component of a
high fibre diet, amounting to 10, 5, or 1 ml enzyme supematant/kg straw. The
enzyme was diluted with water at appropriate rates to obtain an application rate of
300ml/kg straw. The fourth (control) group was treated with water at the same
application rate. The trial was conducted over a period of six weeks, during which
feed intakes, weekly weight gains, as well as feed conversion efficiencies were
recorded. Results suggested significant weight gains in the high (10ml/kg) and
medium (5ml/kg) treatment groups, indicated by a P-value of 0.04. Similarly, feed
conversion efficiencies were improved for above-mentioned groups (P=0.05), while
feed intakes did not differ significantly between the four experimental groups. / AFRIKAANSE OPSOMMING: Die herkouer besit die vermoee om ruvoere beter as enige ander produksiedier te kan
benut. Die gebruik van ruvoervesel is 'n belangrike aspek van herkouer
produksiesisteme, aangesien ruvoere die hoof bron van energie aan die herkouer
verskaf. Die beskikbaarheid van hoe-vesel ruvoer nutriente word egter beperk deur
die degradeerbaarheid van die selwand, en aangesien lae kwaliteit ruvoere 'n groot
bydrae tot wereldwye herkouer-produksiesisteme maak, is die moontlike verbetering
van hierdie degraderingsproses van groot ekonomiese belang.
In 'n poging om hierdie verteringsproses te help bevoordeel, is die gebruik van
eksogene veselverterende ensieme ondersoek, en positiewe resultate is verkry
wanneer hierdie ensieme in in vitro studies gebruik is. Goeie verbeterings ten opsigte
van ruvoer verteerbaarheid en ander diereproduksie parameters is ook verkry deur
middel van in vivo studies waar eksogene ensieme by die ruvoer van herkouers
gevoeg IS.
Twee eksperimente is ondemeem in 'n poging om ensiempreparate wat 'n moontlike
positiewe effek op in vitro veselvertering mag he, te identifiseer. Die eerste, 'n in
vitro organiese materiaal verteerbaarheid tegniek, was suksesvol in die identifisering
van minstens ses ensiem preparate wat statisties betekenisvolle verbeterings ten
opsigte van verteringsresultate geproduseer het. 'n Tweede in vitro gasproduksie prosedure is vervolgens gebruik om resultate verkry vanaf die eerste tegniek, te
bevestig, asook om evalueringskapasiteit te vergroot en sodoende, nuwe
ensiempreparate meer tydseffektief te evalueer. Statistiese evaluering van resultate
verkry uit die tweede in vitro tegniek het 'n reeks ensieme met positiewe resultate
opgelewer. Een van hierdie, Ab0374, het statisties betekenisvolle resultate ten opsigte
van die kontrole, sowel as ander ensieme getoon.
In 'n volgende eksperiment is 'n groeiproef gedoen om die effektiwiteit van hierdie
ensiem in vivo te toets. In die proef is 32 Dohne Merino ramlammers op grond van
hul gewig in vier groepe van agt skape elk verdeel, en individueel gevoer. Die groepe
het verskillende toedieningsvlakke van die toetsensiem, toegedien tot die koringstrooi
komponent van 'n hoe-vesel dieet, ontvang. Toedieningsvlakke was 10, 5, of lml
ensiemkonsentraat/kg strooi. Elke groep se ensiemkonsentraat is verdun met die
toepaslike hoeveelheid water om 'n toedieningsvlak van 300ml ensiemoplossing/kg
koringstrooi te verkry. 'n Vierde groep is behandel slegs met water teen dieselfde
toedieningsvlak, en het gedien as 'n kontrole. Die eksperiment is oor 'n periode van 6
weke uitgevoer. Tydens die proeftydperk is voerinnames, weeklikse gewigstoenames,
sowel as voeromsetverhoudings, gedokumenteer. Resultate het betekenisvolle
gewigstoenames in die hoe (lOml/kg) en medium (5ml/kg) groepe opgelewer,
aangedui deur 'n P-waarde van 0.04. Voeromsetverhoudinge het ook verbeteringe
getoon vir bogenoemde twee groepe (P=0.05), terwyl voerinnames nie merkbaar
tussen die vier groepe verskil het nie.
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Genetic parameter estimates for weaning traits in a multibreed beef cattle populationMelka, Hailu Dadi 12 1900 (has links)
Thesis (MScAgric)--University Stellenbosch, 2001. / ENGLISH ABSTRACT: The aim of this study was to estimate genetic parameters as well as to evaluate the
influence of some genetic factors on preweaning growth traits in a multi breed beef cattle
population. These preweaning growth traits were birth weight (BW), weaning weight
(WW) and average daily gain (ADG). Three aspects were addressed in this particular
study; namely the Estimation of (co)variance components and genetic parameters, the
effect of sire breeds and dam genotypes and the contribution of Charolais and Angus
breeding levels on weaning traits in a multibreed beef cattle herd.
Variance components and resulting genetic parameters of BW, WW and ADG in the
population were estimated by Restricted Maximum Likelihood (REML) procedures. Four
different unitrait and multitrait animal models were fitted ranging from a simple model
with the animal direct effects as the only random effect to the model allowing for both
genetic and permanent maternal environmental effects. The model that included directgenetic and permanent maternal environmental effects generally best described the data
analysed. The simple model ignoring maternal effects most likely inflated direct
heritability estimates. Direct heritability estimates were 0.11, 0.19, and 0.15 for BW,
WW and ADG, respectively, fitting a multitrait model that comprised of both the genetic
and maternal environmental effects. Under this comprehensive model, maternal
heritabilties were low under both analyses, ranging from 0.02 to 0.10. Permanent
maternal environmental effects were more important than maternal additive genetic
effects for WW and ADG. Direct and maternal genetic correlations range from 0.42 to
0.44 for BW, -0.22 to -0.25 for WW and -0.17 to -0.23 for ADG, while the corresponding
estimates ofunitrait analysis varied from 0.58 to 0.61 for BW, -0.43 to-0.53 for WW and
-0.49 to -0.79 for ADG.
The effect of Charolais and Hereford sires and dam breed genotypes on BW and WW in
calves of Hereford, F I, two and three breed rotational as well as terminal crosses among
the Charolais, Hereford, Angus and Bonsmara breeds were investigated. BW and WW of
the Charolais sired calves were significantly (P<O.OOl) heavier than the Hereford sired
calves. Angus dams produced calves of smaller (P<0.05) BW than those of purebred and
crossbred dams. The majority of the crossbred dams were not significantly different in
BW of calves. With regard to WW, with the exception of 3/4H1I4A, all crossbred dams
were superior (P<0.05) to Angus and Hereford dams. Calves of crossbred dams were on
the average 8% heavier at weaning than calves of purebred dams. Crossbred dams, with
intermediate Charolais contribution tend to wean heavier calves.
Data collected were also analysed to determine the optimum breeding levels of Charolais
and Angus, fitting a unitrait animal model. Further, the estimated heritabilities were
subsequently used to predict direct and maternal breeding values (Best linear unbiased
predictions) for individual animals. Best linear unbiased estimates (BLUEs) were also
calculated for the traits. BLUEs, direct and maternal breeding values per genetic group
estimated were regressed on proportions of Charolais and Angus breeding, respectively.
BLUEs of BW, WW and ADG increased with increasing the proportion of Charolais
while they decreased with increasing Angus breeding levels. In general, maternal
breeding values increased with increasing the proportions of both breeds. Direct breeding
values of Charolais increased and reached maximum values at 35, 38, and 45%
proportion of Charolais for BW, WW and ADG, respectively. No optimal Angus
proportion was found within these specific environmental conditions. In this herd it may
be suggested that increasing the proportion of Charolais to intermediate levels would tend
to improve the performances of preweaning traits. / AFRIKAANSE OPSOMMING: Die doel van die studie was om genetiese parameters in 'n meerras vleisbeeskudde te
beraam, sowel as om die invloed van sekere genetiese faktore te evalueer. Die voorspeense
groei-eienskappe het geboortegewig (BW), speengewig (WW) en gemiddelde daaglikse
toename (ADG) ingesluit. Drie aspekte is in dié betrokke studie ondersoek, naamlik; die
beraming van (ko )variansiekomponente en genetiese parameters, die invloed van ras van
vader en moedergenotipe en die invloed van Charolais en Angus bydrae op
speeneienskappe in 'n meerras vleisbeeskudde.
Variansiekomponente en afgeleide genetiese parameters vir BW, WW en ADG in die
kudde is met behulp van die Beperkte Maksimum Waarskynlikheidsprosedure (REML)
beraam. Vier verskillende enkel- en meereienskapmodelle is gepas, wat vanaf 'n
eenvoudige model wat slegs die direkte effek as enigste toevallige effek, tot dié model
waarin beide die genetiese en permanente mateme omgewingseffekte ingesluit is. Die
model wat beide die direkte en permanente mateme effekte ingesluit het, het die data die
beste gepas. Die eenvoudige model, wat die mateme effekte nie insluit nie, het in alle
waarskynlikheid die direkte oorerflikhede oorberaam. Die direkte oorerflikheidsberamingsas onderskeidlik 0.11, 0.19 en 0.15 vir BW, WW en ADG met dié meereienskapmodel
wat beide genetiese en mateme effekte ingesluit het. Met die omvattende model was die
mateme oorerflikhede laag en het van 0.02 tot 0.10 gewissel. Die permanente mateme
omgewingseffekte was belangriker as die direkte mateme effekte vir WW en ADG. Die
genetiese korrelasies tussen direkte en mateme effekte het vir BW tussen 0.42 en 0.44, vir
WW tussen -0.22 en -0.25 en vir ADG tussen -0.49 en -0.79 gewissel.
Die invloed van Charolais en Hereford bulle en moederrasgenotipes op BW en WW van
Hereford, F 1, twee- en drieras rotasie sowel as terminale kruisings tussen die Charolais,
Hereford, Angus en Bonsmara is ondersoek. BW en WW van kalwers van Charolais bulle
was betekenisvol (P<O.OOl) swaarder as kalwers van Hereford bulle. Angus koeie het
kalwers met laer (P<0.05) BW as die van ander suiwer en kruisraskoeie geproduseer.
Kalwers van die meerderheid kruisraskoeie het egter nie in BW verskil nie. Wat WW
betref, maar met die uitsondering van %HYtA, was alle kruisraskoeie beter (P<0.05) as
beide Angus en Hereford koeie. Kalwers van kruisraskoeie was gemiddeld 8 % swaarder
met speen as kalwers van suiwerraskoeie. Kruisraskoeie met intermediêre vlakke van
Charolaisbydrae het geneig om die swaarste kalwers te speen.
Die data is verder ook geanaliseer om die optimum vlakke van Charolais en Angus, deur
die passing van 'n enkeleienskap dieremodel, te bepaal. Die beraamde oorerflikhede is
vervolgens gebruik om direkte en mateme teelwaardes (Beste liniêre onsydige voospellers )
vir individuele diere te voorspel. Beste liniêre onsydige beramings (BLUE's) is ook vir
elke eienskap bereken. Die regressies van BLUE's, direkte en mateme teelwaardes per
genetiese groep bereken, is vervolgens op proporsie Charolais en Angus bydraes
onderskeidelik gepas. BLUE's vir BW, WW en ADG het met toename In
Charolaisproporsie toegeneem, terwyl dit met toename in Angusbydrae afgeneem het. In
die algemeen het mateme teelwaardes met toename in die bydrae van beide rasse
toegeneem. Direkte teelwaardes van die Charolais het toegeneem en maksimum waardes
by 35, 38 en 45 % proporsie Charolais vir onderskeidelik BW, WW en ADG bereik. Vir
die Angus is geen optimum proporsie in dié spesifieke omgewing gevind nie. In dié kudde
word intermediêre Charolais vlakke vir die verbetering van voorspeense eienskappe
aanbeveel.
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The influence of processing of soyabeans and sunflower seed on their energy and amino acid availability for poultryDe Beer, Marc 03 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: 1. The effect of heat-treatment and dehulling of full-fat soya (Glycine
max) on AMEn' amino acid availability and broiler performance.
Heat treatment and dehulling of full-fat soya were evaluated in terms of their effect on
AMEn, apparent amino acid availability and broiler performance. Four products were
tested: raw whole soya (RWS), raw dehulled soya (RDS), extruded whole soya
(EWS) and extruded dehulled soya (EDS). Trials were conducted to determine AMEn
values and apparent amino acid availability of the products. A 42-day broiler trial was
conducted to measure the effect of extrusion and dehulling on broiler performance.
Test products were added to the diets at levels up to 263.2 g/kg in the starter diet and
260.0 g/kg in the finisher diet. Results indicated that extrusion cooking improved
AMEn and apparent amino acid availability. This was reflected in the improved
performance of broilers fed extruded soya as compared to raw soya. Increasing
amounts of RWS and RDS led to decreases in mass and intake and poor feed
conversion ratio (FeR) due to the presence of anti-nutritional factors. Broilers fed
EWS were heavier, consumed more feed and had better FeR than those fed RWS or
RDS. Dehulling improved AMEn (EWS: 13.75 MJ/kg vs EDS: 15.09 MJ/kg) and
rendered a product with slightly higher levels of total amino acids. Broiler
performance did not reflect this as there was no difference in mass, intake or FeR
between broilers fed increasing levels of EWS or EDS. Lysine and arginine were less
available in EDS than EWS indicating the possible over-cooking of EDS. Levels of
EWS and EDS of 263.2 g/kg in the starter and 260.0 g/kg in the finisher supported
maximum broiler performance.
2. The effect of heat-treatment and dehulling of full-fat sunflower
(Helianthus annuus) on AMEm amino acid availability and broiler
performance.
Heat treatment and dehulling of full-fat sunflower were evaluated in terms of their
effect on AMEn, apparent amino acid availability and broiler performance. Four
products were tested: raw whole sunflower (RWSF), raw dehulled sunflower (RDSF),
extruded whole sunflower (EWSF) and extruded dehulled sunflower (ED SF). Trials
were conducted to determine AMEn values and apparent amino acid availability of the
products. A 42-day broiler trial was conducted to measure the effect of expansion and
dehulling on broiler performance. Test products were added to the diets at levels up to
115.0 glkg in the starter diet and 181.5 glkg in the finisher diet. Dehulling rendered a
product with higher crude protein, ether extract, amino acid and AMEn values. AMEn
was only slightly improved by expansion. The AMEn values obtained were: RWSF:
16.03 MJ/kg, RDSF: 18.87 MJ/kg, EWSF: 16.22 MJ/kg, EDSF: 19.49 MJ/kg.
Dehulling had no effect on apparent amino acid availability. Expansion did not affect
apparent amino acid availability of dehulled full-fat sunflower but had a negative
influence on apparent amino acid availability of whole sunflower seeds. This
highlights the possible dangers of reduced protein quality as a result of overprocessing.
No differences were observed in terms of mass, intake and feed
conversion ratio of broilers fed any of the products during the 42-day broiler growth
trial. All products supported optimum broiler performance at levels up to 115.0 glkg
in the starter diet. For the finisher diets, optimum performance was maintained at
levels of 181.5 glkg, for RDSF and EDSF, while performance of broilers fed RWSF
and EWSF was optimal up to 145.2 glkg. / AFRIKAANSE OPSOMMING: 1. Die invloed van hitte-behandeling en ontdopping van
volvetsojabone (Glycine max) op SMEm skynbare aminosuur
beskikbaarheid en braaikuikenprestasie.
Hitte-behandeling en ontdopping van volvetsojabone is ge-evalueer in terme van hul
invloed op stikstof gekorrekteerde skynbare metaboliseerbare energie (SMEn)
waardes, skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Vier produkte
is getoets: rou heel sojabone (RWS), rou ontdopte sojabone (RDS), geekstrueerde
heel sojabone (EWS) en geekstrueerde ontdopte sojabone (EDS). Proewe is uitgevoer
om die SMEn waardes en skynbare aminosuur beskikbaarheid van die vier produkte te
bepaal. Gedurende 'n braaikuikengroeitoets van 42 dae is die invloed van hittebehandeling
(ekstrusie) en ontdopping op braaikuikenprestasie gemeet. Die vier
toetsprodukte is ingesluit in die aanvangsdieet teen peile van tot 263.2 g/kg en teen
peile van tot 260.0 g/kg in die afrondingsdieet. Resultate het getoon dat ekstrusie die
SMEn waardes en skynbare aminosuur beskikbaarheid verbeter het. Braaikuikens wat
geekstrueerde soja ontvang het, het beter gepresteer as braaikuikens wat rou soja
ontvang het. Verhoogte insluitings van RWS en RDS het gelei tot verlagings in massa
toename en voerinname en swak voeromsetverhoudings (VOV), as gevolg van die
teenwoordigheid van anti-voedings faktore. Braaikuikens wat EWS ontvang het, was
swaarder, het meer ingeneem en het beter vav gehad as die wat RWS of RDS
ontvang het. Ontdopping het SMEn verhoog (EWS: 13.75 MJ/kg vs EDS: 15.09
MJ/kg) en ontdopte produkte het klein hoeveelhede meer aminosure bevat. Dit het
egter nie in braaikuikenprestasie gewys nie. Daar was geen verskille in massa,
voerinname en vav tussen braaikuikens wat EWS of EDS ontvang het. Lisien en
arginien was minder beskikbaar in EDS as EWS wat op die moontlike oorprosessering
van EDS dui. Vlakke van EWS en EDS van 263.2 g/kg in die
aanvangsdieet en 260.0 g/kg In die afrondingsdieet het maksimale
braaikuikenprestasie ondersteun. 2. Die invloed
volvetsonneblosaad
van hitte-behandeling
(Helianthus annuus)
en ontdopping van
op SMEo, skynbare
aminosuur beskikbaarheid en braaikuikenprestasie.
Hitte-behandeling en ontdopping van volvetsonneblomsaad is geevalueer in terme van
hul invloed op stikstof gekorrekteerde skynbare metaboliseerbare energie (SMEn)
waardes, skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Vier produkte
is getoets: rou heel sonneblomsaad (RWS), rou ontdopte sonneblomsaad (RDS),
geekspandeerde heel sonneblomsaad (EWS) en geekspandeerde ontdopte
sonneblomsaad (EDS). Proewe is uitgevoer om die SMEn waardes en skynbare
aminosuur beskikbaarheid van die vier produkte te bepaal. Gedurende 'n
braaikuikengroeitoets van 42 dae is die invloed van hitte-behandeling (ekspansie) en
ontdopping op braaikuikenprestasie gemeet. Die vier toetsprodukte is ingesluit in die
aanvangsdieet teen peile van tot 115.0 g/kg en teen peile van tot 181.5 g/kg in die
afrondingsdieet. Ontdopte sonneblomsaad het hoer peile van ruproteien, eter-ekstrak
en aminosure as heel sonneblomsaad. SMEn waardes is ook hoer vir ontdopte
sonneblomsaad. Hitte-behandeling het SMEn waardes effens verhoog. Die bepaalde
SMEn waardes is as volg: RWSF: 16.03 MJ/kg, RDSF: 18.87 MJ/kg, EWSF: 16.22
MJ/kg, EDSF: 19.49 MJ/kg. Ontdopping het geen invloed op skynbare aminosuur
bekikbaarheid gehad nie. Skynbare aminosuur beskikbaarheid van ontdopte
sonneblomsaad IS me deur hitte-behandeling beinvloed nie, terwyl die van heel
sonneblomsaad negatief beinvloed is. Dit beklemtoon die gevare van verswakte
proteien kwaliteit as gevolg van oor-prosessering. Geen verskille is opgemerk in
terme van massa, voerinname en voeromset verhouding (VOV) tussen die vier
produkte gedurende die braaikuikengroeitoets van 42 dae. Alle produkte het
maksimale braaikuiken prestasie ondersteun in die aanvangsdieet teen vlakke van
115.0 g/kg. In die afrondingsdieet het RDSF en EDSF optimale braaikuikenprestasie
onderhou teen vlakke van 181.5 g/kg, terwyl RWSF en EWSF net t
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The effect of endosperm vitreousness on fermentation characteristics and in vitro digestibility of maizeBurden, Petro Trudene 12 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The purpose of this study was to investigate the variation that exists between maize samples regarding
particle size separation, in vitro fermentation kinetics and in vitro dry matter (DM) disappearance. A second
objective was to quantify possible relationships between the Roff Milling Index (RMI) of maize and any of the
measured in vitro parameters. Three trials were conducted: a particle size distribution trial, a gas production
trial and an in vitro DM degradability and starch disappearance trial.
Overall, nine maize samples, which differed in terms of cultivar and endosperm type, were collected from
different origins for the study. The samples were selected in terms of their Milling Index (MI). Three of the
nine samples had a high MI that ranged between 109 and 118, three had a low MI that ranged between 67
and 71 and the other three samples had a medium MI that ranged between 85 and 92. Although the MI is not
a direct indication of the hardness or softness of the endosperm, it was believed to be indirectly associated
with vitreousness.
In the first trial, the different maize samples were milled through a 1 mm screen and sieved through a series
of three sieves 150, 125 and 106 μm, respectively. It was found that RMI was not a reliable indicator to
predict particle size distribution, especially in terms of the coarse (>150 μm) and very fine (<106 μm)
particles.
In the gas production trial, the nine different maize samples were subjected to a gas production system for a
duration of 48 hours. Here gas production and rate of gas production of the different maize types in buffered
rumen liquor were measured during incubation. After fitting the gas volume data to the respective models,
the non-linear parameters b, c and L were subjected to a main effects ANOVA with the aid of Statistica,
version 9 (2009). Main effects were treatment and repetition. Means were separated by means of a Scheffé
test and significance was declared at P < 0.05. The results were compared to the RMI of the different maize
types and it was concluded that RMI was not a reliable predictor of gas production or rate of gas production
of different maize types.
In the third trial, in vitro DM degradability and starch disappearance of the different maize types were
measured. In vitro DM degradability was conducted in the Ankom DAISYII incubator apparatus and the incubation times were 0, 2, 4, 8, 12 and 24 hours. Starch disappearance was measured on residues of the
samples incubated for 0, 2 and 4 hours. After fitting the DM disappearance data to the respective models,
the non-linear parameters a, b, c and L were subjected to a main effects ANOVA with the aid of Statistica,
version 9 (2009). Main effects were treatment and repetition. Means were separated by means of a Scheffé
test and significance was declared at P<0.05. The results indicated variation between maize samples,
especially in terms of the a-, b- and L-values. The RMI did not appear to be a reliable predictor of digestibility
parameters. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die variasie tussen mieliemonsters te ondersoek ten opsigte van die
skeiding van partikelgroottes, in vitro-fermentasiekinetika en in vitro-droëmateriaalverdwyning. ‘n Tweede
doel was om te bepaal of daar moontlike verwantskappe tussen die Roff Milling Index (RMI) van mielies en
enige van die ander in vitro-parameters bestaan. Drie proewe is gedoen: verspreiding van partikelgrootte, ‘n
gasproduksieproef en ‘n droëmateriaal degradeerbaarheid- en stysel verdwyningsproef.
Nege mieliemonsters, wat van mekaar verskil ten opsigte van kultivar en endospermtipe, is van verskillende
lokaliteite versamel. Die monsters is gekies in terme van hul maal-indeks (MI). Drie van die nege monsters
het ‘n hoë MI gehad wat gewissel het tussen 109 en 118, drie het ‘n lae MI gehad wat gewissel het tussen
67 en 71 en die ander drie monsters het ‘n medium MI gehad wat gewissel het tussen 85 en 92. Alhoewel
die MI waardes nie ‘n direkte indikasie van ‘n endosperm se hardheid- of sagtheidsgraad is nie, is dit
aanvaar dat daar ‘n indirekte verwantskap tussen MI en glasagtigheid van die mielie bestaan.
In die eerste proef is die nege verskillende mieliemonsters deur ‘n 1 mm sif gemaal en daarna deur ‘n reeks
van drie siwwe met groottes van onderskeidelik 150, 125 en 106 μm gesif. Daar is bevind dat die RMI nie ‘n
betroubare voorspeller is om partikelgrootte-verspreiding aan te dui nie, veral nie ten opsigte van growwe (>
150 μm) en baie fyn (< 106 μm) patikels nie.
Tydens die gasproduksieproef is die nege mieliemonsters vir 48 ure blootgestel aan ‘n gasproduksiesisteem,
waar gasdruk outomaties aangeteken is. Gasproduksie en tempo van gasproduksie van die verskillende
mieliemonsters is gemeet en aangeteken gedurende inkubasie met ‘n gebufferde rumenvloeistofmedium.
Nadat die gasvolumedata met behulp van relevante modelle gepas is, is die nie-linêre parameters b, c en L
onderwerp aan ‘n hoof-effek ANOVA met die gebruik van Statistica weergawe 9 (2009). Hoof-effekte was
behandeling en herhaling. Gemiddeldes is deur ‘n Scheffé-toets geskei en betekenisvolheid is verklaar by
P<0.05. Die resultate verkry is vergelyk met die RMI van die verskillende mielietipes. Die gevolgtrekking is
gemaak dat Roff MI nie ‘n betroubare voorspeller van totale gasproduksie of gasproduksietempo is nie.
Tydens die derde proef is droëmateriaaldegradeerbaarheid en styselverdwyning van die verskillende
mielietipes bepaal. In vitro droëmateriaal (DM) degradeerbaarheid is gedoen in die Ankom DAISYII inkubator
met inkubasietye van 0, 2, 4, 8, 12 en 24 ure. Styselverdwyning is bepaal deur styselanalises op die residue van die monsters wat geïnkubeer is vir 0, 2 en 4 ure. Nadat die DM-degradeerbaarheid met behulp van
relevante modelle gepas is, is die nie-lineêre parameters a, b, c en L onderwerp aan ‘n hoof-effek ANOVA
met die gebruik van Statistica weergawe 9 (2009). Hoof-effekte was behandeling en herhaling. Gemiddeldes
is deur ‘n Scheffé toets geskei en die betekenisvolheid is verklaar by P<0.05. Die resultate het aangedui dat
daar groot variasie tussen mielies bestaan, veral ten opsigte van die a-, b- en L-waardes. Dit het verder
geblyk dat die RMI van die verskillende mielietipes nie ‘n betroubare voorspeller van DM-degradeerbaarheid
was nie.
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Melamine, from fertilizer to pasture to cow’s milkBotha, Dawn Dorothy 12 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The aim of this study was to determine the rate of transfer of melamine as fertilizer ingredient to
kikuyu pastures and if melamine would be transferred from the fertilized pasture to cow’s milk.
Three trials were conducted in the study, viz. a pilot pot plant trial, an applied pasture trial and a
milk production trial.
Melamine is a commercially available industrial chemical with a high nitrogen content. Large
quantities of melamine waste can sometimes be incorporated into crop and pasture fertilizers due
to the high N content. An initial pot plant trial with kikuyu was conducted to determine whether
melamine would be absorbed as such from the soil to the plant material. The pots were fertilized in
the form of melamine adulterated Chinese maize Gluten 60, at a rate equivalent to 8.8 kg of
melamine/ha. Results indicated that melamine was indeed absorbed and 7 days after fertilization,
the concentration of melamine in the grass was 228 mg/kg.
An applied pasture trial was then conducted were three pastures of 0.3 ha each were used. One
pasture served as a control and received N fertilization in the form of LAN at a rate of 40 kg N/ha.
The other two pastures also received LAN, but with 10% (Treatment 1) and 20% (Treatment 2) of
the LAN-N substituted with melamine-N. All three pastures also received P-fertilization in the form
of Single Superphosphate at a rate of 20 kg P/ha and KCl fertilizer at a rate of 50 kg K/ha. Pasture
samples were taken once a week for 10 weeks, each time at the exact same spot in each camp.
Samples were dried and finely milled before analysis via LC-MS/MS for melamine content. The
initial concentration of melamine in the grass of Treatment 2 was higher than that in the grass of
Treatment 1. The rate at which melamine decayed in the plant material was found to be quite
similar for the two melamine treatments. In this trial, melamine took around 10 weeks to reach
undetectable levels in the grass. It was concluded that melamine was absorbed as such from the
soil by pasture grass when included in a fertilizer.
For the milk production study, eighteen lactating Holstein cows, 60 ± 5.1 (SE) DIM, with a daily milk
production of 36.5 ± 2.0 (SE) kg/d and weighing 609 ± 12.8 (SE) kg, were stratified according to milk production and then randomly allocated to three groups of six cows. The groups were then
randomly allocated to the three pastures used in the applied pasture trial. Cows were kept on the
melamine fertilized pasture for 9 days, in which they were allowed to graze the pasture for
approximately 10 hours each day. After the 9 day period, melamine was withdrawn by placing the
cows on the control pasture that did not receive melamine contaminated fertilization for another 7
days. During these 16 days, milk was collected twice a day, viz. during the morning and afternoon
milkings. Milk samples of each cow were sub-divided into two samples, one was preserved with
potassium dichromate and analysed for milk composition and the other was frozen until analysed
for melamine by LC-MS/MS. For the duration of the trial, melamine containing milk was destroyed
in order to prevent it from contaminating milk collected from the rest of the herd. Results from the
analysis for melamine confirmed that melamine was transferred from melamine fertilized pasture to
milk. In this study, it took 6 days from melamine withdrawal for melamine to reach undetectable
levels in the milk. It was also found that the melamine fertilized pasture did not have any significant
effect on the average milk production and milk composition of the cows. The aim of the study was
met and it was confirmed that melamine can be transferred from fertilizer to the soil, to the pasture and to the milk of cows grazing these pastures. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die tempo van oordrag van melamien as bemestingstof na
Kikuyu weiding te bepaal, asook om te bepaal of melamien oorgedra sal word vanaf die bemeste
weiding na melk. Drie proewe is uitgevoer wat ‘n potplant loodsproef, ‘n toegepaste weidings proef
en ‘n melkproduksie proef ingesluit het.
Melamien is ʼn kommersieël-beskikbare industriële chemikalieë met ʼn hoë stikstof inhoud. Groot
hoeveelhede van melamien-afval kan soms in kunsmis ingesluit word vir die bemesting van
gewasse en weidings, weens die hoë stikstof inhoud van melamien. ʼn Potplant loodsproef met
Kikuyu is uitgevoer om te bepaal of melamien vanaf die grond deur die plantmateriaal geabsorbeer
word. Melamienbemesting is in die vorm van vervalste Chinese mieliegluten 60 toegedien teen ʼn
hoeveelheid gelykstaande aan 8.8 kg melamien/ha. Die resultate van hierdie proef het getoon dat
melamien wel deur die plantmateriaal geabsorbeer is en 7 dae nadat bemesting toegedien is, was
die konsentrasie van melamien in die gras 228 of mg/kg.
ʼn Toegepaste weidingstudie is uitgevoer waar drie kampe van 0.3 ha elk gebruik is. Een van die
kampe het as ʼn kontrole gedien en het stikstof bemesting in die vorm van KAN teen 40 kg N/ha
ontvang. Die ander twee kampe het KAN bemesting ontvang waar 10% (Behandeling 1) en 20%
(Behandeling 2) van die KAN-N deur melamien-N vervang is. Al drie kampe het ook
fosfaatbemesting in die vorm van Enkel Superfosfaat ontvang teen 20 kg P/ha, asook KCl kunsmis
teen 50 kg K/ha. Weidingmonsters is eenmaal per week op dieselfde plek in elke kamp geneem vir
10 weke nadat bemesting toegedien is geneem. Monsters is gedroog en daarna fyngemaal
voordat dit vir melamieninhoud geanaliseer is met behulp van LC-MS/MS. Die aanvanklike
melamienkonsentrasie in die gras van Behandeling 2 was hoër as die in die gras van Behandeling
1. Die tempo waarteen die melamienkonsentrasie in die plant materiaal afgeneem het, was baie
dieselfde vir Behandelings 1 en Behandeling 2. Dit het ongeveer 10 weke geneem voordat die
melamien in die gras nie-waarneembare vlakke bereik het. Die gevolgtrekking is gemaak dat
melamien wat in die vorm van kunsmis toegedien word, as sodanig uit die grond geabsorbeer word
deur die gras. Vir die melkproduksiestudie is agtien lakterede Holsteinkoeie, 60 ± 5.1 (SE) dae in melk, met ‘n
daaglikse melkproduksie van 36.5 ± 2.0 (SE) kg/dag en ‘n liggaamsmassa van 609 ± 12.8 (SE) kg,
volgens hul melkproduksie gerangskik en ewekansig in drie groepe van ses koeie elk ingedeel. Die
groepe is daarna ewekansig aan die drie kampe, wat in die toegepaste weidingstudie gebruik is
toegedien. Die koeie is vir 9 dae op die melamienbemeste weidings gehou, waartydens hulle
toegelaat is om vir ongeveer 10 ure elke dag te wei. Na die tydperk van 9 d, is die koeie vanaf die
melamienbemeste weidings onttrek deur hulle op die kontroleweiding te plaas vir ʼn verdere 7 dae.
Gedurende hierdie 16 dae is melkmonsters tweekeer per dag geneem, tydens die oggend- en die
middagmelkings. Die melkmonsters van elke koei is vervolgens onderverdeel in twee monsters,
waarvan een met kaliumdichromaat gepreserveer is vir die beplaing van melksamestelling, terwyl
die ander een gevries is totdat dit later vir melamien inhoud ontleed is met behulp van LC-MS/MS.
Melk van die koeie wat op die melamienweidings gewei het, is weggegooi om te voorkom dat melk
van die res van die kudde gekontamineer kon word. Die resultate van die melamienanalises het
getoon dat melamien oorgedra word vanaf die melamienbemeste weiding na die melk. Tydens
hierdie studie het dit 6 dae geneem vandat koeie vanaf die melamienbemeste weidings onttrek is,
totdat die melkmelamien nie-bepaalbare vlakke bereik het. Daar is bevind dat melamienbemeste
weidings geen betekenisvolle uitwerking op die gemiddelde produksie en samestelling van die
melk gehad het nie. Die doel van hierdie studie is bereik en daar is getoon dat melamien vanaf
kunsmis na die grond, na die gras en na die melk oorgedra kan word wanneer koeie op weidings
geplaas word wat melamienbemeste kunsmis ontvang het.
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'n Studie van dorperskaapboerdery in die dorperlandgebiedAckermann, Jacobus Johannes 12 1900 (has links)
Thesis (MScAgric) -- Stellenbosch University, 1993. / ENGLISH ABSTRACT: A model of interdependents that makes provision for the particular needs of dorper
sheep farming and is based on the relationship between the main groups of
behaviour determined variables, was constructed. This model served as a basis for
an interview schedule whereby personal interviews were held with 130 randomly
drawn dorper farmers in the summer rainfall area of the Dorperland. Various
independent and mediatory variables were examined and in certain cases it was
quantified. Thus certain relationships between the needs, aspirations and
endeavours of the respondents and their particular personal and environmental
factors were determined. The determination of the independent and mediatory
variables provide the extension officer with important background information
whereby the application/non-application of certain practices as well as the
efficiency of practice application are put into perspective. In this respect the
findings of this survey serve as an important reference point by which specified
extension actions could be evaluated in the future. The effectiveness of practice
application is determined on the basis of 5- and 10-point scales as well as a description of what is actually done. In doing this the existence of certain definite
differences between the perceptions of the respondent~ concerning the efficiency
of praxis application and the assessment of the interviewers, baled on •
description of what is actually done, was found. Practice accepta1Ce, •
manifested in efficiency is measured on the basis of particular effectivity stMcWds.
Thus relationships between the efficiency standards and certain personal, socioeconomical,
socia-psychological and biological-technical variables wet"d
determined. / AFRIKAANSE OPSOMMING: 'n Model van interafhanklikes wat voorsiening maak vir die eiesoortige behoeftes
van dorperskaapboerdery en gebaseer is op die verwantskap tussen die
hoofgroepe van gedragsbepalende veranderlikes, is gekonstrueer. Hierdie model
het as basis gedien vir 'n onderhoudskedule aan die hand waarvan persoonlike
onderhoude met 130 ewekansig gelote dorperboere in die somerreenvalgebied
van Dorperland gevoer is. Verskeie onafhanklike en bemiddelende veranderlikes is
ondersoek en in sekere gevalle is dit gekwantifiseer. Sodoende is verwantskappe
tussen die behoeftes, aspirasies en strewes van die respondente en bepaaIde
persoonlike- en omgewingsfaktore van sodanige respondente bepaal. Die
bepaling van die onafhanklike- en bemiddelende veranderlikes bied die voorligter
belangrike agtergrondinligting op grond waarvan die toepassing/nie-toepassing
van bepaalde praktyke asook die doeltreffendheid van praktyktoepassing in
perspektief geplaas word. Die mate waartoe sekere praktyke wat met
dorperskaapboerdery verband hou toegepas word. is ook bepaal. In hierdie verband dien die bevindinge van hierdie ondersoek as belangrike verwysingspunte
aan die hand waarvan bepaalde voorIigtingsaksies in die toekoms geevalueer kan
word. Die doeltreffendheid van praktyktoepassing is aan die hand van 5- en 10puntskale.
asook 'n omskrywing van wat werklik gedoen word, bepaaI. Sodoende
is die bestaan van sekere duidelike verskille tussen die persepsies van die
respondente wat betref die doeltreffendheid van praktyktoepassing en die aansIag
van opnemers, gebaseer op 'n beskrywing van wat werklik gedoen word, bevind.
Praktykaanvaarding, saos dit manifesteer in doeltreffendheid. is aan die hand van
bepaalde doeltreffendheidsmaatstawwe gemeet. Sodoende is verwantskappe
tussen die doeltreffendheidsmaatstawwe en sekere persoonlike, sosio-ekonomiese,
sosio-psigologiese en biologies-tegniese bepaal.
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The effect of highly digestible carbohydrate and protein sources included in pre-starter diets of broilers on their performancePretorius, Charne 03 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: In recent years, the aim of the production of broilers became more focused on the increase of the
performance of the birds in order to increase profit. To obtain an increased performance with broiler
chicks, it is necessary to look at the development of their gastrointestinal tract, the feed requirements and
the ability to digest certain nutrients in the period post hatch. Research have shown clear evidence of
increased performance of chicks by the inclusion of certain carbohydrate and protein sources in the prestarter
diets, but in contrast to this there are also some research that found no significant effects on the
performance of broilers when certain carbohydrate and protein sources were included in the pre-starter
diet. Therefore, the purpose of this study was to investigate the effect that a product containing specific
carbohydrate and protein sources, included in the pre-starter diets of broiler chicks, would have on their
performance. It was believed that the products to be tested would result in increased performance of the
chicks in the following growth phases. Special emphasis was placed on the average daily gain (ADG),
feed intake, cumulative feed intake, feed conversion ratio (FCR), European production efficiency factor
(EPEF) and the protein efficiency ratio.
Different inclusion levels of the different raw materials were investigated in the first trial. Three raw
materials and a control were compared using a summit dilution process at 100:0, 66:34, 50:50, 34:66 and
0:100. Specific production parameters such as ADG total live weight gain, feed intake per week,
cumulative feed intake, FCR, EPEF and PER were measured and calculated in order to determine if there
were any significant differences between the treatments with the different raw material inclusions on the
performance of the chicks. No significant differences (P>0.05) were found between the 13 treatments for
the ADG, total live weight gain, feed intake per week, cumulative feed intake, FCR, EPEF and PER. The
results therefore indicated that there were no significant differences between the different inclusion levels
of the different raw materials and no significant differences for the production parameters for animals
receiving diets with various levels of the three raw materials. It is thus concluded that these raw materials
can be successfully utilised in pre-starter diets of broiler chicks.
The effect of the contribution of sugar to the metabolisable energy (ME) of the raw materials was tested in
a commercial grower trial. The three raw materials had inclusion levels leading to supply of either 12% or
18% of the ME in the form of sugar. No significant differences were found between the seven treatments
for ADG, total live weight gain, feed intake per week, cumulative feed intake, FCR, EPEF or the PER. It
was concluded that the percentage in contribution of sugars between 12 and 18% to the ME of the prestarter
diets had no significant effects on the production parameters tested. / AFRIKAANSE OPSOMMING: Met die produksie van braaikuikens word daar deesdae al hoe meer klem gelê op die verhoging van die
produksie van die kuikens om dan dus ‘n verhoging in die wins te bewerkstellig. Om hierdie verhoogde
produksie by braaikuikens te kan bereik, is dit nodig om na eienskappe van die kuiken soos die
ontwikkeling van die spysvertering stelsel, die nutrient- behoeftes van die kuiken en die vermoë om
sekere nutriënte te kan verteer in die periode na uitbroei. Sommige navorsing het gewys dat die insluiting
van sekere koolhidraat – en proteïen bronne in die voor-aanvangs diëete van braaikuikens, lei tot ‘n
positiewe effek op die produksie van die kuikens, waar ander navorsing geen effek gevind het nie.
Daarom was die doel van die huidige navorsing gewees om te toets wat die effek van die insluiting in die
voor-aanvangs dieet van braaikuikens ‘n sekere produk met ‘n spesifieke koolhidraat –en proteïen bron
samestelling op die produksie van die kuikens sal wees in die daaropvolgende fases. Dit was verwag dat
die insluiting van hierdie produkte in die voor-aanvangs diëte van braaikuikens ‘n positiewe effek sou hê
op die produksie van die kuikens. Spesiale klem was gelê op die parameters soos gemiddelde daaglikse
toename (GDT) voer inname, kumulatiewe voer inname, voeromset verhoudings (VOV) Europese
produksie doeltreffendheids- faktor (EPEF) en die proteïen doeltreffendheids faktor (PER).
Verskillende insluitings vlakke van die verskillende produkte wat getoets is, is in die eerste proef
ondersoek. Die drie produkte is deur middel van ‘n piek verdunnings proses by verhoudings van 100:0,
66:34, 50:50, 34:66 en 0:100 met mekaar vergelyk. Spesifieke produksie- parameters soos die GDT,
lewende massa, weeklikse voer- inname, kumulatiewe voer- inname, VOV, EPEF en die PER is gemeet.
Geen betekenisvolle verskille (P>0.05) was vir die 13 behandelings verkry nie. Die resultate het derhalwe
getoon dat daar geen betekenisvolle verskille tussen die verskillende insluitings vlakke van die
onderskeie produkte was nie en dat daar geen betekenisvolle tussen die produksieparameters van die
kuikens wat die diëte met die verskillende insluitingspeile van die drie roumateriale ontvand het, was nie.
Daarom is tot die slotsom gekom dat hierdie roumateriale suksesvol in die vooraanvangsdieet van
braaikuikens aangewend kan word.
Die effek van die bydrae van die suiker tot die metaboliseerbare energie (ME) van die produkte was in ‘n
kommersiële groei proef getoets. Die drie rou materiale was by beide 12- en 18% ingesluit. Geen
betekenisvolle verskille (P>0.05) was vir die sewe behandelings vir GDT, lewende massa, weeklikse
voer- inname, kumulatiewe voer- inname, VOV, EPEF en PEF verkry nie.
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The proximate, fatty acid and mineral composition of the muscles of cultured yellowtail (Seriola lalandi) at different anatomical locationsBurke, Andrew Brian 03 1900 (has links)
Thesis (MPhil (Animal Sciences))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: The proximate composition of food products, and more importantly fat content and fatty acid
composition, is of growing concern to consumers. It is also of concern to fish processors
because of the effects that various levels of proteins, lipids, water and ash have on the cold
storage potential and texture of fish. A total of 17 Seriola lalandi (yellowtail) were harvested
from a net cage production unit off the coast of Port Elizabeth. Proximate, fatty acid and
mineral analysis were conducted on five areas on the fillet, as well as on the whole fillet as a
control. Differences (P < 0.05) were found in the water and fat content between dorsal and
ventral samples. The highest amount (% wet weight) of moisture (71.5 ± 0.4%) was observed
in the caudal region of the fish. This region was also found to contain the lowest levels of fat
(4.3 ± 0.23%). Protein levels did not differ (P > 0.05) between sample regions. The total fat
content (g/100 g wet tissue) of the whole fillet (A; control) was 5.3 ± 0.11 of which saturated
fatty acids (SFA) accounted for 35.5 ± 1.13%, monounsaturated fatty acids (MUFA) for 25.7
± 0.51% and polyunsaturated fatty acids (PUFA) for 38.2±0.88%. The most predominant
saturated fatty acid was palmitic acid (hexadecanoic acid, C16:0) with levels reaching 24.2 ±
1.25% in the mid belly area, sample section E (mid ventral). The data shows that one could
use either section B (anterior dorsal), section D (mid dorsal) or section F (dorsal and ventral
posterior sections combined) as a representative sample of the whole fillet when doing
proximate analysis. The belly sections of the fish differed significantly (P < 0.05) to the
whole fillet. There was too much variation between samples with regards to the mineral and
fatty acid analysis to identify a section that is representative of the whole fillet. The edible
portion of the farmed yellowtail examined in this study contained eicosapentonic acid (EPA)
and docosahexaenoic acid (DHA) levels of 0.24% and 10.90% respectively which is notably
lower than other marine fish species. However, this could be linked to the feed that these
specific yellowtail were fed, as the lipid profile of the diet has been shown to have an effect
on the lipid profile of the fish. / AFRIKAANSE OPSOMMING: Die algemene samestelling van voedsel produkte, asook die vet inhoud en vetsuur
samestelling daarvan, wek deesdae al meer besorgdheid by verbruikers. Dit is ook belangrik
vir vis verwerkers as gevolg van die effek wat verskillende vlakke van proteïene, lipiede,
water en minerale het op die tekstuur van vis asook die potensiaal om vis in verkoelers te
stoor. ‘n Totaal van 17 Seriola lalandi (geelstert) is geöes vanuit ‘n net-hok eenheid op die
kus van Port Elizabeth. Proksimale, vetsuur en mineraal analises was uitgevoer op vyf areas
van die filet sowel as op die heel filet as ‘n kontrole. Verskille (P < 0.05) is opgemerk in die
water en vet inhoud tussen die dorsale en ventrale monsters. Die hoogste voginhoud (71.5 ±
0.4%) was opgemerk in die stert gedeelte van die vis en hierdie gedeelte het ook die laagste
vetinhoud gehad (4.3 ± 0.23%). Proteïen vlakke het nie verskil tussen enige van die monsters
nie (P < 0.05). Die totale vetinhoud (g/100 g nat weefsel) van die heel filet (A, kontrole) was
5.3 ± 0.11 waarvan versadigde vetsure (SFA) 35.5 ± 1.13%, monoönversadigde vetsure
(MUFA) 25.7 ± 0.51%, en polionversadigde vetsure (PUFA) 38.2 ± 0.88% uitgemaak het.
Die oorheersende versadigde vetsuur was palmitiese suur (heksadekanoïese suur, C16:0) wat
vlakke van 24.2 ± 1.25% bereik het in seksie E (middel ventraal). Die data wys dat seksie B
(voorste dorsaal), seksie D (middel dorsaal) of seksie F (agterste ventraal en dorsaal) gebruik
kan word as verteenwoordigende monsters van die heel filet wanneer proksimale analise
uitgevoer word. Die maag gedeeltes van die vis het beduidend verskil (P < 0.05) van die heel
filet. Die resultate van die mineraal en vetsuur analises het te veel gevarieer en daarom kon
geen verteenwoordigende seksie van die heel filet geïdentifiseer word nie. Die eetbare dele
van akwakultuur geelstert wat in hierdie studie ondersoek is, bevat 0.24% EPA en 10.90%
DHA wat heelwat laer is as die van ander marine vis spesies. Hierdie verskil kan moontlik
toegeskryf word aan die voer wat aan die geelstert gegee is aangesien dit voorheen bewys is
dat die lipied profiel van die dieet ‘n uitwerking het op die lipied profiel van vis.
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Estimation of genetic distances and heterosis in three ostrich (Struthio camelus) breeds for the improvement of productivityDavids, Annelin Henriehetta 03 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: A study was conducted to characterize the three ostrich breeds available as genetic resource in South
Africa, namely the South African Black (SAB), Zimbabwean Blue (ZB) and the Kenyan Redneck (KR), and
their respective crosses. Growth, slaughter traits and reproduction of these ostriches were recorded at
Oudtshoorn Research Farm in the Western Cape of South Africa. Individual non-linear regressions
(Gompertz) were fitted to the data of 390 purebred and 41 crossbred ostriches, using the SAS NLIN function.
Heterosis was estimated for each parameter of the Gompertz model. The estimated adult weight (Aparameter)
of the ZB (147 kg) and the KR breeds (148 kg) were higher than that of the SAB breed (129 kg).
The overall growth rate (B-parameter) of the ZB breed (0.0075) and the SAB breed (0.0080) was lower than
that of the KR (0.0150). The age at maximum weight gain (C-parameter) was higher for the ZB breed (226
days) compared to the SAB (198 days) and the KR (194 days). Heterosis for the A-parameter was estimated
at -6.2% and at -12% for the C-parameter. The slaughter traits studied were slaughter weight (SLW), carcass
weight (CW), dressing percentage (DP), fan fillet weight (FFW), pH0, pH24, drip loss % (DL%), cooking loss
% (CL%), tenderness and meat colour traits. Differences were observed between the means for SLW of the
SAB (86.5 kg) and ZB (93.9 kg). Mean DP of the KR breed (52.5%) was increased relative to the low DP of
their SAB contemporaries (48.8%). The sire lines (ZB and KR) and crosses were heavier than the SAB (dam
line), whereas the crosses resembled the dam line for meat quality traits. Means for pH24 also differed, with
higher values for the sire lines (ZB – 6.36; KR – 6.4) relative to the SAB (5.85). The instrumental b* colour
value also differed between the SAB (9.4) and KR (6.9). Records used for assessing the reproduction and
body measurements of purebred and crossbred dams were 428 in total. Traits analyzed were, total egg
production (TEP), the number of fertile eggs, number dead in shell chicks, hatchability and chick production
(CP), the time to lay, live weight, front chest circumferences as well as tail circumference. The ZB and KR
were heavier in live weight and of larger body measurements than the SAB, whereas the SAB exhibited
superior reproduction performance in comparison with the ZB and KR breeds. Derived heterosis estimates
amounted to 2.2% for tail circumference, 12% for TEP, 12% for hatchability and 19% for CP. Genetic
variation between and within the breeds were determined utilizing 19 microsatellite markers. Significant
molecular genetic differences were observed between the three breeds. The SAB and ZB (Fst = 0.10 and
Nei = 0.49) were genetically most similar, whereas the genetic distance between the KR and ZB breeds were
furthest (Fst = 0.13 and Nei = 0.61). The SAB breed exhibited the highest heterozygosity within its population
and the ZB the lowest heterozygosity. These results contribute to a better understanding of the utilization of
the distinct ostrich breeds for commercial production. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die verskille tussen drie volstruisrasse wat tans in Suid Afrika mee
geboer word te karakteriseer, naamlik die “South African Black” (SAB), “Zimbabwean Blue” (ZB) en die
“Kenyan Redneck” (KR) en hulle onderskeie kruisse. Rekords van die groei-, slag- en reproduksie
eienskappe van die volstruise was by Oudtshoorn Navorsingsplaas in die Wes-Kaap aangeteken. Individuele
nie-lineêre regressies (Gompertz) is op die data van 390 suiwerras en 42 kruisgeteelde volstruise gepas,
met die gebruik van die “NLIN” prosedure van SAS, (2006). Heterose is beraam vir elke parameter van die
Gompertz model. Die beraamde volwasse gewig (A-parameter) van die ZB (147 kg) en die KR ras (148 kg)
was hoër as die van die SAB ras (129 kg). Die totale groeitempo (B-parameter) van die ZB ras (0.0075) en
die SAB ras (0.0080) was laer as die van die KR (0.0150). Die ouderdom by maksimum groei (C-parameter)
was hoër vir die ZB ras (226 dae) in vergelyking met die SAB (198 dae) en die KR (194 dae). Heterose vir
die A-parameter was beraam teen -6.2% en teen -12% vir die C-parameter. Die slageienskappe wat
ondersoek was, was slagmassa (SLW), karkasmassa (CW), uitslag persentasie (DP), “fan fillet” massa
(FFW), pH0, pH24, drupverlies % (DL%), kookverlies % (CL%), sagtheid en kleureienskappe.
Beduidendende verskille is waargeneem tussen die gemiddeldes vir SLW vir die SAB (86.5 kg) en ZB (93.9
kg). Gemiddelde DP van die KR ras (52.5%) was beter as die van die SAB ras (48.8%). Die mannetjielyne
(ZB en KR) en die kruisse was swaarder as die SAB (wyfielyn), en die kruise was vergelykbaar met die
wyfielyn vir vleiskwaliteit eienskappe. Gemiddeldes vir die pH24 het verskil, met hoër waardes vir die vaar
lyne (ZB – 6.36; KR – 6.4) relatief tot die SAB (5.85). Die instrumentale b* kleurwaarde het ook verskil tussen
die SAB (9.4) en KR (6.9). ‘n Totaal van 428 rekords is gebruik om reproduksie en liggaamsmetings van die
suiwer en kruisteelwyfies te ondersoek. Reproduksie eienskappe ge-analiseer was: die aantal broeisels,
totale eierproduksie (TEP), die aantal vrugbare eiers, die aantal kuikens dood in dop, uitbroeibaarheid,
kuiken produksie (CP), tyd tot produksie van die eerste eier, volwasse gewig, voorbors omtrek, sowel as,
kruisomtrek. Die ZB en KR rasse was swaarder as die SAB, en het groter liggaamsmetings gehad. Die SAB
het beter reproduksie in vergelyking met die ZB- en KR rasse gehad. Heterose beramings was 2.2% vir
kruisomtrek, 12% vir TEP, 12% vir uitbroeibaarheid en 19% vir CP. Genetiese variasie tussen en binne die
rasse was vasgestel deur die gebruik van 19 mikrosatelliete merkers. Beduidende genetiese verskille op ‘n
molekulêre vlak was waargeneem tussen die drie rasse. Die SAB en ZB (Fst = 0.10 en Nei = 0.49) was
geneties meer gelyk terwyl die KR en ZB genetiese verder verwyder is (Fst = 0.13 en Nei = 0.61). Die SAB
ras het die hoogste heterosigositeit binne populasie getoon, en die ZB die laagste. Hierdie resultate dra by
tot ‘n beter begrip van die gebruik van die drie rasse in kommersïele produksie.
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The evaluation of larvae of Musca Domestica (common house fly) as protein source for boiler productionPretorius, Quinton 03 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: The objective of this study was to evaluate the use of Musca domestica (common house fly) larvae meal, as
protein source, for broiler production. This was done by investigating the nutritive value of house fly larvae meal
together with its total tract digestibility, potential toxicity and carcass characteristics of the broilers supplemented
with house fly larvae meal. The proximate analysis of house fly larvae meal show that it contained, on a dry
matter basis, a gross energy value of 20.10 MJ/kg, 60.38% crude protein, 14.08% crude fat and 10.68% ash and
that the house fly pupae contained a gross energy of 20.42 MJ/kg, 76.23% crude protein, 14.39% crude fat and
7.73% ash. House fly pupae meal had the closest match of amino acid profile when compared with the ideal
amino acid profile required by broilers and it has arginine relative to the lysine content closer to the ideal amino
acid profile than the house fly larvae meal. The essential fatty acid, linoleic acid, was found at levels of 26.25
and 36.27% of the total fats for the house fly larvae and pupae meal respectively. House fly larvae meal
supplementation did not induce gizzard erosion or showed toxicity (regarding the gastro intestinal tract, immune
system and organ stress) in broilers.
Results revealed that house fly pupae meal had higher total tract digestibilities for most nutrients than of the
house fly larvae meal. House fly larvae meal had a crude protein total tract digestibility of 69% and that of pupae
meal was 79%. Both larvae and pupae meal had high amino acid total tract digestibilities of all the amino acids
analysed. The house fly larvae and pupae meal had an apparent metabolizable energy (AME) value of
14.23MJ/kg and 15.15MJ/kg respectively. The larvae meal total tract crude fat and crude fibre digestibilities
were 94% and 62% respectively. The pupae meal total tract crude fat and crude fibre digestibilities were 98%
and 58% respectively.
House fly larvae meal supplementation in a three phase feeding system significantly increased average broiler
live weights at slaughter, total feed intake, cumulative feed intake as well as average daily gain (ADG) when
compared to commercial maize: soya oil cake meal diet. In direct comparison of larvae inclusion levels with
fishmeal in isonitrogenous and isoenergetic diet, no significant differences were observed between a 10% house
fly larvae and a 10% fish meal diets regarding performance characteristic. The 25% house fly larvae meal diet
yielded significantly better average broiler live weights at slaughter, total feed intake, cumulative feed intake
(from the second week until slaughter) as well as average daily gain when compared to the 25% fish meal diet in
the growth phases.
Carcass characteristics of the 10% larvae, 10% fishmeal and commercial diets were compared. Chicks that
received either the 10% house fly larvae meal or 10% fish meal supplementation produced significantly heavier carcasses and breast muscle portions than the chicks that received the commercial maize: soya oil cake meal.
No treatment differences were found regarding breast and thigh muscle colour or pH.
This study showed that house fly larvae meal can be regarded as a safe protein source that can be used to
replace other protein sources and that has the ability to promote broiler performance without having any
detrimental effects on carcass characteristics. / AFRIKAANSE OPSOMMING: Die doel van die studie was om die effek van Musca domestica (gewone huisvlieg) larwe meel, as ‘n protein
bron, in braaikuikens te evalueer. Dit was gedoen deur die nutrient waarde van huisvlieg larwe meel saam met
die totale spysvertering verteerbaarheid, moontlike toksiesiteit en karkas-eienskappe van braai kuikens te
evalueer. Laboratoruim analiese toon dat huisvlieg larwe meel 20.10 MJ/kg bruto energie, 60.38% ru- protein,
14.08% ru- vet en 10.68% as bevat en huisvlieg papie meel 20.42 MJ/kg bruto energie, 76.23% ru- protein,
14.39% ru- vet en 7.73% as bevat. Huisvlieg papie meel stem die meeste ooreen met die idiale amino suur
profiel soos wat benodig word deur braaikuikens en dit het ‘n arginien tot lisien verhouding wat die meeste
ooreenstem met die idiale amino suur profiel in vergelyking met huis vlieg larwe meel. Die essensiele vet suur,
linolien suur, was geanaliseer teen vlakke van 26.25- en 36.27% van die totale vette onderskeidelik vir huisvlieg
larwe- en papie meel. Huisvlieg larwe meel vervanging het nie spiermaag erosie of enige ander toksiese effekte
te veroorsaak nie.
Resultate het getoon dat huisvlieg papie meel, in vergelyking met larwe meel, het ‘n hoër totale spysvertering
verteerbaarheid vir meeste van die nutrient. Die huisvlieg larwe meel het ‘n totale ru- protein spysvertering
verteerbaarheid van 69% en die van papie meel van 79%. Beide larwe en papie meel het hoë amino suur
spysvertering verteerbaarheid. Larwe meel en papie meel het skynbare metaboliseerbare energie waardes van
14.23MJ/kg en 15.15%MJ/kg onderskeidelik. Die larwe meel het ‘n ru-vet en ru- vesel spysvertering
verteerbaarheid van 94% en 62% onderskeidelik, waar die papies ‘n ru-vet en ru- vesel spysvertering
verteerbaarheid van onderskeidelik 98% en 58% het.
Huisvlieg larwe meel vervanging in ‘n drie fase voer stelsel het getoon om die gemiddelde braaikuiken lewende
gewigte by slag, totale voer iname, sowel as die gemiddelde daaglikse toename te verhoog waneer dit vergelyk
word met ‘n kommersiele mielie- soya olie koek dieet. Geen mekwaardige verskille was waargeneem toe die
10% larwe meel dieet direk met die 10% vismeel diet vergelyk was rakende enige produksie einskappe gemeet
nie. Die 25% larwe meel dieet het merkwaardig beter gemiddelde braaikuiken lewende gewigte by slag, totale
voer iname, sowel as die gemiddelde daaglikse toename getoon wanneer vergelyk word met die 25% vismeel
dieet gedurende die verskeie groei fases.
Karkas eienskappe van die 10% larwe meel, 10% vismeel en die kommersiele diete was gevergelyk. Kuikens
wat 10% larwe meel en 10% vismeel in die diete ontvang het, het swaarder karkasse gelewer met swaarder
borsie massas wanneer vergelyk word met die kommersiele mielie- soya olie koek dieet. Geen behandelings
verskille was gevind rakende die borsie- en dy spier kleure of pH nie. Die studie toon dat huisvlieg larwe meel as ‘n veillige protein bron kan beskou word, wat gebruik kan word om
ander protein bronne te vervang. Huisvlieg larwe meel het ook die vermoë om braaikuiken produksie te verhoog
sonder om enige negitiewe effekte rakende die karkas eienskappe te toon nie.
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