Call number: LD2668 .T4 1951 C53 / Master of Science

Call number: LD2668 .T4 1955 K56 / Master of Science

Call number: LD2668 .T4 1965 D54 / Master of Science

Call number: LD2668 .T4 1966 M848 / Master of Science

Call number: LD2668 .T4 1966 R313 / Master of Science

No description available.

Thesis (PhD) -- tellenbosch University, 2014. / ENGLISH ABSTRACT: This study is part of the continuing global research effort dedicated to finding alternative aquafeed ingredients, which not only replace fish meal and fish oil as sources of essential nutrients in aquafeeds, but also provide specialist functional properties when included in feeds. Due to constraints in supply of fish meal and fish oil originating from wild capture fisheries, the continually growing aquafeed industry requires new sources of raw materials for the production of high quality feeds. The aim of the study was to investigate the specialist functional properties of feed ingredients (with emphasis on immune-stimulation potential) derived from fish processing waste after enzymatic hydrolysis by endogenous proteolytic enzymes (autolysis). Further aims were to (i) quantify effects of these feed ingredients on production performance of two species relevant to the South African aquaculture industry, namely Mozambique tilapia Oreochromis mossambicus and South African abalone Haliotis midae, (ii) compare performance to commercially available enzymatically produced feed ingredients, and (iii) separate the functional effects of these fish processing waste derived feed ingredients from the acid used to preserve them against bacterial spoilage during the autolysis process. Oil recovered after autolysis of rainbow trout viscera proved to be an attractive feed ingredient due to favourable effects on the non-specific cellular immune function of both Mozambique tilapia and South African abalone. However, in South African abalone, increased immune function due to inclusion of fish oil was accompanied by a significant decrease in production performance. The inclusion of hydrolysed proteins, obtained by autolysis of fish waste, in aquaculture feeds also improved non-specific immunity and survival of Mozambique tilapia significantly – independently of the preserving acid – although the same was not observed for South African abalone. Production performance was dependent on dietary hydrolysed protein inclusion levels in both species; excessive inclusion resulted in decreased production performance. The performance of dietary hydrolysed protein from autolysis and those from commercial production processes were significantly different, possibly as a result of different raw material origins and production processes. It is further shown that formic acid can contribute to improved water stability in abalone feeds, a novel mode of action not previously described. The study concludes that the simple autolysis process for processing of fish waste can provide aquafeed ingredients with immune stimulatory potential, which can contribute to improved production performance in the Mozambique tilapia and the South African abalone. The result can contribute to improved sustainability of the aquafeed industry, through substitution of fish meal and fish oil derived from capture fisheries with processed fish waste components. / AFRIKAANSE OPSOMMING: Hierdie studie vorm deel van die voortdurende en wêreldwye soeke na nuwe akwakultuur voerbestanddele wat nie net vismeel en –olie kan vervang as bron van noodsaaklike voedingstowwe nie, maar wat ook gespesialiseerde funksionele eienskappe openbaar wanneer dit in akwavoere ingesluit word. As gevolg van beperkings in die voorsiening van vismeel en –olie afkomstig vanaf wilde visserye, word die voortdurend groeiende akwavoer bedryf genoodsaak om nuwe grondstowwe te benut vir die vervaardiging van hoë kwaliteit voere. Die doelwit van die studie was om moontlike gespesialiseerde funksionele eienskappe (met spesifieke klem op potensiële immuun-stimulasie) van voerbestanddele te ondersoek wat herwin is vanaf reënboogforel proseseringsafval, na ensiematiese hidrolise d.m.v. endogene ensieme teenwoordig in die afval (outolise). Verdere doelwitte was om (i) effekte op produksie prestasie van hierdie bestanddele te kwantifiseer in twee akwakultuur spesies relevant tot die Suid- Afrikaanse bedryf (naamlik die Mosambiekse kurper Oreochromis mossambicus en die Suid- Afrikaanse perlemoen Haliotis midae), (ii) om produksie prestasie te vergelyk met kommersieel beskikbare voerbestanddele voorberei d.m.v. ensiemtegnologie, en (iii) om die moontlike effekte van die voerbestanddele te skei van die van die sure gebruik om die bestanddele te preserveer tydens die outolitiese proses. Daar is bevind dat olie herwin na outolise van reënboogforel ingewande ‘n goeie voerbestanddeel is wat gunstige effekte op die nie-spesifieke, sellulêre immuniteit van beide Mosambiekse kurper en Suid-Afrikaanse perlemoen gehad het. In die Suid-Afrikaanse perlemoen het verbeterde immuunfunksie gepaard gegaan met ‘n verswakking in produksie prestasie. Die gehidroliseerde proteïen komponent van ge-outoliseerde prosesseringsafval het ook beduidende verbetering in nie spesifieke immuniteit en oorlewing van Mosambiekse kurper tot gevolg gehad - onafhanklik van die preserverende suur - maar dieselfde is nie in die Suid-Afrikaanse perlemoen waargeneem nie. Produksie prestasie was afhanklik van die insluitingsvlakke van gehidroliseerde proteïen in beide spesies en dit is bevind dat oormatige insluiting produksie nadelig beïnvloed. Prestasie van proteïen afkomstig van outolise en die van ‘n kommersiële produksieproses het beduidend verskil, moontlik as gevolg van verskillende grondstowwe en prosesseringstegnieke. Daar is verder vir die eerste keer getoon dat mieresuur ‘n beduidende verbetering in waterstabiliteit in sekere perlemoenvoere teweeg kan bring. Die studie kom tot die slotsom dat die eenvoudige outolise proses funksionele akwavoerbestanddele kan produseer wat kan bydra tot ‘n verbetering in produksie prestasie in die Mosambiekse kurper en Suid-Afrikaanse perlemoen. Die resultaat kan bydra tot verbeterde volhoubaarheid van die akwavoer bedryf, deur vismeel en –olie afkomstig van wilde visserye, te vervang.

Thesis (MScAgric)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Veal production is a specialised form of calf rearing in which calves were traditionally raised on all-liquid diets. The early weaning of calves onto concentrated diets provides an economically viable alternative rearing method with comparable calf performance. The emphasis in meat production has shifted to the production of lean meat, therefore the deposition of protein instead of fat has become a priority. The optimum level of dietary crude protein for growing calves is well established. Very little, however, is known about the influence of protein degradability in the diet of young ruminants. Recommendations by the NRC are derived from data obtained using lactating dairy cows. The aim was to obtain data on which recommendations for the level of degradable protein in starter and finisher diets for calves could be based. Two experiments were conducted to examine the effect of different levels of dietary crude protein degradability in starter and finisher calf diets on veal calf performance. In both experiments Holstein bull calves were 3 - 10 days of age at the onset, weaned at 4 weeks of age and slaughtered at 20 weeks of age for veal. In Experiment 1 calves were randomly assigned to one of three treatments: low (LO), medium (MD) and high (HO) rumen degradable protein. Calves received a starter diet up to 11 weeks of age and finisher diets from week 12 - 20. In Experiment 2 calves received a starter diet either high or low in rumen degradable protein up to 10 weeks of age. In the finishing period (week 11 - 20) both the low and high groups were again divided into a low and high group, resulting effectively in 4 treatments, viz. LL, LH, HL and HH. The diets in both experiments were formulated to be iso-nitrogenous and iso-caloric, differing only in rumen undegradable protein content within periods and. respective experiments. Body weight gain, feed intake and feed conversion efficiency data for the preweaning, starter, finishing and total experimental period was compared between treatments. There were no significant differences for feed intake, body weight gain or feed efficiency in the starter period of both experiments between treatments. In the finishing period of Experiment 1 the average daily gain for the LO treatment was significantly higher than for the HO treatment, with the MD treatment having an intermediate value. The feed conversion ratio (FCR) for the LO treatment was also significantly better than for the other two treatments. In Experiment 2 the FCR tended (P = 0.0984) to differ between treatments in the finishing period. Calves from the LL and HL treatments had a more favourable FCR than calves from the LH treatment. The HH treatment had an intermediate FCR. According to these results crude protein degradability appears to have an effect on the FCR in the finishing period. The lack of response to higher levels of undegradable dietary protein in calves younger than 10 weeks may be due to underdeveloped rumen functions and it seems possible for high degradable protein to escape degradation to a higher extent than at a later age. In a third experiment, Holstein bull calves and Holstein cows were used to determine and compare the dry matter and crude protein degradability of the four calf diets used in Experiment 2. Rumen VFA concentrations, pH level and NH3-N concentrations were measured for the cannulated Holstein calves to evaluate the level of rumen metabolic maturity of growing calves. Five Holstein bull calves were ruminally cannulated at 6 weeks of age. Dry matter and crude protein degradability were determined once weekly from week 8 - 20 by means of 24 h in sacco incubations. Three ruminally cannulated Holstein cows were used to determine the comparable values for mature ruminants. Dry matter and crude protein degradability differed significantly between the low and high degradable diets for both calves and cows. Dry matter and crude protein degradability in calves increased up to 11 and 12 weeks of age respectively, and then appeared to remain constant to week 20. Dry matter and crude protein degradability values of the starter diets were lower for the calves than for the cows, but values were similar for the finisher diets. Rumen VFA concentrations, pH level and NH3-N concentration showed some fluctuation between weeks, but were similar to literature values for mature animals. / AFRIKAANSE OPSOMMING: Titel: Die invloed van verskillende vlakke van proteïendegradeerbaarheid in aanvangs- en afrondingsdiëte op kalfprestasie in 'n kalfsvleisproduksiestelsel. Kalfsvleisproduksie is 'n gespesialiseerde grootmaakstelsel wat tradisioneel alleenlik op vloeistofdiëte gebaseer was. 'n Stelsel waar kalwers vroeg gespeen word en 'n volledige aanvangs- en afrondingsrantsoen ontvang, bied 'n alternatiewe metode wat ekonomies lewensvatbaar is en vergelykbare kalfprestasie tot gevolg het. Die klem in vleisproduksie het verskuif na die produksie van maervleis. Die neerlegging van proteïen in plaas van vet het dus 'n prioriteit geword. Die optimale vlak van dieetproteïen vir groeiende kalwers is deeglik nagevors. Baie min is egter bekend oor die invloed van proteïendegradeerbaarheid in die dieet van jong herkouende diere. Aanbevelings deur die NRC is afkomstig van data verkry van studies met melkproduserende koeie. Die doel was om data te bekom waarop aanbevelings vir die vlak van degradeerbare proteïen in aanvangs- en afrondingsdiëte vir kalwers gegrond kan word. Twee eksperimente is uitgevoer om die invloed van verskillende vlakke van proteïendegradeerbaarheid in aanvangs- en afrondingsdiëte op kalfprestasie in 'n kalfsvleisproduksiestelsel te ondersoek. Holstein bulkalwers was 3 - 10 dae oud met die aanvang van beide eksperimente, is gespeen op 4 weke ouderdom en op 20 weke ouderdom vir kalfsvleis geslag. In Eksperiment 1 is kalwers ewekansig aan een van drie behandelings toegewys: lae (LO), medium (MD) en hoë (HO) rumen degradeerbare proteïen. Kalwers het tot op 11 weke ouderdom aanvangsdiëte ontvang, terwyl afrondingsdiëte vanaf 12 - 20 weke ouderdom aangebied is. In Eksperiment 2 het kalwers tot op 10 weke ouderdom "n dieet wat óf hoog óf laag in rumen degradeerbare proteïen was, ontvang. In die afrondingsperiode (week 11 - 20) is die lae en hoë groepe elk vervolgens in "n lae en hoë groep verdeel wat effektief tot 4 behandelings gelei het, nl. LL, LH, HL en HH. Die diëte in albei eksperimente was geformuleer om iso-nitrogenies en iso-kalories te wees. Slegs die rumen degradeerbare proteïeninhoud het tussen die onderskeie diëte binne "n bepaalde periode en eksperiment verskil. Gewigstoename, voerinname en voeromsettingsdoeltreffendheid vir die voorspeense-, aanvangs-, afrondings- en totale eksperimentele periode is tussen behandelings vergelyk. In beide eksperimente is geen betekenisvolle verskille gedurende die aanvangsperiode waargeneem t.o.v. voerinname, massatoename en voeromsettingsdoeltreffendheid (VOD) nie. In die afrondingsperiode van Eksperiment 1 was die gemiddelde daaglikse massatoename van die LO behandeling betekenisvol hoër as dié van die HO behandeling, terwyl die MD behandeling "n intermediêre waarde gehad het. Die VOD vir die LO behandeling was ook betekenisvol beter as vir die ander twee behandelings. Die VOD in die afrondingsperiode van Eksperiment 2 het geneig (P = 0.0984) om te verskil tussen behandelings en kalwers van die LL en HL behandelings het "n meer gunstige VOD as kalwers van die LH behandeling gehad. Die HH behandeling het "n intermediêre VOD gehad. Volgens die resultate van hierdie eksperimente het proteïendegradeerbaarheid in kalfrantsoene waarskynlik "n invloed op VOD in die afrondingsperiode. Die gebrek aan respons as gevolg van hoër insluitingsvlakke van nie-degradeerbare proteïen in die rantsoen by kalwers jonger as 10 weke kan moontlik toegeskryf word aan onderontwikkelde rumenfunksies. Dit blyk moontlik te wees dat die hoë degradeerbare proteïenfraksie by jonger kalwers rumendegradering in "n hoër mate as op "n latere ouderdom vrygespring het. In "n derde eksperiment is Holstein bulkalwers en Holstein koeie gebruik om die droëmateriaal- en proteïendegradeerbaarheid van die vier diëte wat in Eksperiment 2 gebruik is, te bepaal en te vergelyk. Rumen WS-konsentrasies, pH-vlak en NH3-Nkonsentrasies is vir die kalwers gemeet om die vlak van metaboliese rumen volwassenheid van groeiende kalwers te evalueer. Vyf Holstein kalwers is op 6 weke ouderdom ruminaal gekannuleer. Droëmateriaal- en proteïen-degradeerbaarheid is een maal per week vanaf week 8 - 20 deur middel van 24 h in sacco inkubasies bepaal. Drie rumen-gekannuleerde Holstein koeie is gebruik om die vergelykbare waardes van volwasse herkouers te bepaal. Droëmateriaal- en proteïendegradeerbaarheid het betekenisvol tussen die lae en hoë degradeerbare diëte vir beide die kalwers en koeie verskil. Droëmateriaal- en proteïendegradeerbaarheid by die kalwers het tot op 11 en 12 weke ouderdom, onderskeidelik, verhoog en daarna tot week 20 relatief konstant gebly. Die droëmateriaal- en proteïendegradeerbaarheidswaardes van die aanvangsdiëte was laer vir die kalwers as vir die koeie, maar die waardes vir die afrondingsdiëte was eenders. Rumen WS-konsentrasies, pH-vlak en NH3-N-konsentrasies het In mate van fluktuasie tussen weke getoon, maar was soortgelyk aan literatuurwaardes vir volwasse diere.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The objective of this study was to evaluate Dohne Merino sheep and Boer goats in terms of the degradable parameters of a high-fibre diet, a low-fibre diet and two vegetable protein sources commonly used in South Africa. Differences between species were evaluated following the potential differences within species. The feedstuffs used were those for the following diets: low-fibre diet (LF); high-fibre diet (HF); sunflower meal (SFM) oilcake; and soybean meal (SBM) oilcake. In the first trial, the digestible characteristics of the HF and LF diets were determined by means of a digestibility study. A 6 × 6 Latin square design was used to determine whether Dohne Merino sheep or Boer goat wethers differ regarding the digestibility characteristics of low- and high-fibre diets. The diets were fed once daily at 1.24 kg to all the wethers, which had ad libitum access to fresh water. Each period consisted of 10 days of adaptation and seven days of faecal and urinary sampling. The results indicated that the intake and digestibility characteristics of nutrients did not differ between sheep and goats. However, the different diets differed in terms of the nutrient intake and digestibility range of sheep and goats. The second trial was an in sacco degradability trial to determine the dry matter (DM) and crude protein (CP) degradability of the LF, HF, SBM and SFM diets. Six Dohne Merino and six Boer goat wethers were fitted with rumen cannulae so that they could be used in the trial. All wethers received the same basal diet. The samples were incubated in the rumen in polyester Dacron bags, with the bags being removed at intervals of 0h, 3h, 9h, 12h, 24h, 48h, 72h, and 96h for the LF and HF diets. All the oilcake was removed at intervals of 0h, 2h, 4h, 8h, 12h, 16h, 24h, 36h and 48h. The sheep and goats were found not to differ from one another in terms of effective degradability of any of the feedstuffs concerned. However, within species differences were observed. To establish a fully integrated outcome of degradability, the study described in the current thesis was structured in such a way that the in vitro trial ran parallel with the in sacco trial, being performed with the aid of a Daisy Incubator (ANKOM Technology Corp., Fairport, NY). Such a procedure was only adopted in relation to the SFM and SBM diets in order to evaluate their in vitro data in relation to the in sacco data. The same oilcake was tested in the case of both trials, with the composite sample of rumen liquid of four sheep or goats, which was used in the in sacco trial, also being used in the in vitro study. In the study, DM disappearance values were determined and fitted to a single-compartment model by means of an iterative least-square procedure in order to determine the DM and CP degradability parameters. The DM used in vitro or in sacco was compared, using the actual values obtained after 8h incubation, due to only a limited amount of residue being left after incubation. In the study, the in vitro method overestimated the digestibility of SBM by 37% to 39% and the digestibility of SFM by 17% to 20% compared with that found to occur in the in sacco method. In vitro DM disappearance values for all SBM samples were found to be higher than those that were detected in the SFM samples. The percentage of in vitro true digestibility parameters was also calculated. No significant differences were found between species for effective degradability, though differences were observed within species between the two substrates concerned. In conclusion, the sheep and goats used in the study were not found to differ in terms of digestion parameters when they were compared on different types of roughage or protein sources. However, within species differences were, indeed, found to occur. Sheep and goats digested the SBM better than they did the SFM. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om te bepaal of Dohne Merino skape verskil van Boerbokke in terme van degradeerbaarheidsparameters van ‘n hoë vesel-, ‘n lae veseldieët en twee plantaardige proteïenbronne wat algemeen in Suid-Afrika gebruik word. Die verskille tussen spesies is ge-evalueer en daarna die potensiële verskille binne spesies. Die volgende grondstowwe is geëvalueer: ‘n laevesel-dieët (LF), ‘n hoëvesel-dieët (HF), sonneblom-oliekoekmeel (SFM) en sojaboon-oliekoekmeel (SBM). In die eerste proef is die degradeerbaarheidsparameters van die HF dieët en die LF dieët met behulp van ‘n verteerbaarheidstudie bepaal. Dohne Merino hamels of Boerbok kapaters was gebruik om te bepaal of skape en bokke verskil in terme van inname en degradeerbaarheid van voedingstowwe wanneer hul hoë- en lae vesel voere gevoer word. Al die hamels en kapaters het ad libitum toegang tot vars water gehad en hul was een keer per dag (1.24 kg) gevoer. Elke periode het bestaan uit ‘n 10 dag aanpassingsperiode en ‘n toegelate 7 dae vir mis- en urienmonster versameling. Die resultate het aangedui dat die inname- en degradeerbaarheidsparameters van nutriënte beinvloed word deur verskillende diëte binne spesies. Geen verskille is gevind tussen spesies wanneer daar hoë- en lae kwaliteit voere gevoer is nie. Die tweede proef was ‘n in sacco-degradeerbaarheidsstudie om te bepaal wat die droë materiaal (DM) en ruproteïen (RP) verteerbaarheidsparameters van die HF dieët, die LF dieët, die SBM en die SFM is. Ses Dohne Merino’s en ses Boer bokke met rumen kanullas is in die studie gebruik en al die diere het dieselfde basale dieët ontvang. Die monsters is in die rumen geïnkubeer in poliester dakronsakkies en die sakkies is verwyder na onderskeidelik 0 uur, 3 uur, 9 uur, 12 uur, 24 uur, 48 uur, 72 uur en 96 uur intervalle. Laasgenoemde intervalle was geldig vir die lae vesel- en hoëveseldieët. Die oliekoeke se intervalle het verskil en is verwyder na 0 uur, 2 uur, 4 uur, 8 uur, 12 uur, 16 uur, 24 uur, 36 uur en 48 uur. Daar was geen verskille tussen spesies in effektiewe degradeerbaarheid nie, alhoewel verskille voorgekom het binne spesies. Skape verteer veselagtige grondstowwe meer effektief terwyl bokke weer hoë proteïn bevattende grondstowwe beter verteer. Om ‘n volkome geïntegreede uitkoms van degradeerbaarheid te bewerkstellig is die in vitro proef en die in sacco proef gelyktydig gedoen. Die in vitro-degradeerbareheidstudie is met behulp van ‘n ANKOM Daisy Inkubeerder uitgevoer (ANKOM Tegnologie Korp., Fairport, NY) vir net die oliekoek behandelings. Gedurende die studie is dieselfde oliekoeke gebruik. ‘n Saamgestelde monster van die rumenvloeistof van vier van die skape of bokke wat vir die in sacco-studie gebruik was, is gebruik vir die in vitro-inkubasie van die monsters. DM verdwyningparameters is bereken en dan met ‘n interaktiewe kleinste kwadraat prosedure op ‘n een-kompartement model gepas om die in sacco DMdegradeerbaarheidsparameters te bepaal. Die DM verdwyning, na 8h inkubasie, was gebruik om die in vitro en die in sacco metodes met mekaar te vergelyk, weens ‘n beperkte residu na die afloop van die elke inkubasiestudie. Tydens die studie het die in vitro metode degradering oorskat in vergelyking met die in sacco metode. DM verdwyningswaardes vir al die SBM monsters was hoër in vitro as die SFM monsters. In die studie is die persentasie in vitro ware degradeerbaarheidswaardes bereken. Geen verskille is opgemerk tussen spesies vir effektiewe degradeerbaarheid nie. Daar was wel verskille binne spesies. Om af te sluit het dit voorgekom dat skape en bokke nie verskil aan degradeerbaarheidswaardes wanneer daar ‘n vergelyking was tussen verskillende vesels- en proteϊenbronne nie, alhoewel verskille voorgekom het binne spesies. Skape en bokke het SBM effektief beter verteer as SFM.

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy