Experiments were conducted to assess effects of nursery feeding programs (using complex or simple diets, including or excluding antibiotics) on growth performance of barrows and gilts up to market weight (approximately 115 kg body weight), plasma levels of growth-related hormones, chemical body composition and carcass traits at market weight. Reducing nursery diet complexity decreased (P < 0.05) growth performance and plasma levels of triiodothyronine during the nursery period, but had no negative carry-over effects on growth performance or hormone plasma levels thereafter. Excluding antibiotics from nursery diets reduced nursery growth performance and plasma levels of insulin-like growth factor-1 and triiodothyronine but appeared to induce subsequent compensatory growth. In general, nursery feeding programs had no effect on body composition and carcass traits at market weight and no effect on wean-to-finish growth performance or carcass value at market weight. This represents an opportunity to improve profitability in commercial pork production. / Ontario Pork; The Ontario Ministry of Agriculture, Food and Rural Affairs; Canadian Agriculture and Agri-Food Swine Research Cluster

Thesis (PhD (Food Sc))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The wildlife industry in Namibia has shown tremendous growth over the past decades and is currently the only extensive production system in Namibia that is expanding. Harvesting game for the purpose of meat production is a viable option since there is a worldwide demand for healthy and high quality proteins. The main objective of the dissertation was to investigate selected parameters required to develop a sustainable Namibian game meat industry. The major species suitable for commercial harvesting operations are springbok (Antidorcas marsupialis – Zimmerman, 1780), gemsbok (Oryx gazella – Linnaeus, 1785), kudu (Tragelaphus strepsiceros – Pallas, 1766), mountain zebra (Equus zebra hartmannae – Linnaeus, 1758) and red hartebeest (Alcelaphus buselaphus caama – Pallas, 1766). Eland (Tragelaphus oryx – Pallas, 1766) could be considered as a suitable species, although the numbers of animals that can be harvested during an operation are limited. This study demonstrated that gender influenced live weight of springbok, kudu and red hartebeest. Gender also influenced carcass weights for springbok, gemsbok, kudu and red hartebeest, but not for eland, while dressing percentage did not differ between gender for springbok, gemsbok, kudu and red hartebeest. Although there were some statistical differences in the chemical composition of the various muscles from the different species (Mm. biceps femoris, infraspinatus, longissimus dorsi, semimembranosus, semitendinosus and supraspinatus), it is doubtful whether consumers would be able to distinguish between these. Discriminant analysis could not differentiate among the different muscle groups for springbok and gemsbok. A differentiation was, however, revealed among the various muscles for red hartebeest. During the investigation on the influence of season and gender on the carcass yields and meat quality characteristics of kudu and red hartebeest, dressing percentage was affected by season, but not by gender. Muscle colour differed significantly between seasons. Results from this study showed that male eland contained more saturated fatty acids than females, but no gender differences were observed for polyunsaturated fatty acids. Hides of gemsbok, kudu and red hartebeest contributed 6 – 7% of live weight, while the skin of springbok contributed 4 – 5% of live weight. Comparisons of offal items among species showed significant differences for all offal items, except for intestines. Retail cuts showed significant species difference for rump, topside, silverside and sinews. No significant species differences were observed for thick flank and bolo. Significant gender differences were observed for silverside. No interactions between species and gender were found for the different retail cuts from gemsbok and kudu. Microbiological counts of game meat, chilled for 6 weeks and frozen for 12 months, respectively, were found to be within acceptable limits as prescribed by the South African retail market. Differences in physico-chemical and microbiological properties were observed among salami from different game species. The springbok salami was found to be microbiologically unstable. The main characteristics observed while tasting the salami from springbok, gemsbok, kudu and zebra were a distinctive smoky, salty, pepper and salami flavour combined with a smoky, salami aroma. Game flavour did not feature as strong during the sensory analyses. Sustainable utilization of game for commercial meat production has the potential to increase earnings to beneficiaries in the wildlife sector. Results from this study contributed knowledge which can be utilized to develop the Namibian game meat industry. / AFRIKAANSE OPSOMMING: Die wildsbedryf in Namibië het die afgelope dekades buitengewone groei getoon en is huidiglik die enigste ekstensiewe produksie-sisteem wat in Namibië uitbrei. Die oes van wild is ʼn voordelige opsie, aangesien daar wêreldwyd ʼn aanvraag is na gesonde en hoë kwaliteit proteïene. Die hoofdoelwit van hierdie dissertasie was die loods van ʼn ondersoek na geselekteerde aspekte wat benodig word om die Namibiese wildsvleisbedryf te ontwikkel. Die belangrikste spesies geïdentifiseer as geskik vir kommersiële oes, is springbok (Antidorcas marsupialis – Zimmerman, 1780), gemsbok (Oryx gazella – Linnaeus, 1785), koedoe (Tragelaphus strepsiceros – Pallas, 1766), berg sebra (Equus zebra hartmannae – Linnaeus, 1758) en rooihartbees (Alcelaphus buselaphus caama – Pallas, 1766). Eland (Tragelaphus oryx – Pallas, 1766) is ook ʼn geskikte spesies, maar die hoeveelhede wat op een slag geoes kan word, is beperk. Hierdie studie het gedemonstreer dat geslag ʼn invloed op die lewendige gewig van springbok, koedoe en rooihartbees het. Geslag het ook ʼn invloed gehad op karkasgewigte van springbok, gemsbok, koedoe en rooihartbees, maar geen invloed op die karkasgewig van eland nie, terwyl uitslagpersentasie geensins geslagsverskille getoon het vir springbok, gemsbok, koedoe of rooihartbees nie. Nieteenstaande statistiese verskille in die chemiese samestelling van die verskillende spiere van die onderskeie spesies (Mm. biceps femoris, infraspinatus, longissimus dorsi, semimembranosus, semitendinosus en supraspinatus), is dit te betwyfel of verbruikers ʼn onderskeid sal kan tref tussen die spiere. Diskriminant-analise kon nie verskille uitwys tussen die verskillende groepe spiere van springbok en gemsbok nie. Verskille was egter te bespeur tussen verskillende spiere van die rooihartbees. Gedurende hierdie ondersoek is die invloed van seisoen en geslag op die karkasopbrengs en vleiskwaliteit van koedoe en rooihartbees ondersoek. Uitslagpersentasie is beïnvloed deur seisoen, maar nie deur geslag nie. Kleur het betekenisvol verskil tussen seisoene. Resultate van die studie het getoon dat elandbulle meer versadigde vetsure het as koeie, maar dat geen verskille vir geslag gevind is vir poli-onversadigde vetsure nie. Gemsbok-, koedoe - en rooihartbeesvelle het 6 – 7% bygedra tot die lewendige gewig, terwyl die vel van die springbok 4 – 5% bygedra het. Vergelykings van afvalopbrengs tussen spesies het verskille uitgewys ten opsigte van al die items, behalwe die ingewande. Kleinhandelsnitte het betekenisvolle verskille getoon vir die kruis, binneboud, dy en senings. Geen betekenisvolle spesies verskille is opgemerk vir die diklies en bolo nie. Die dy het betekenisvolle verskille tussen geslagte getoon. Geen interaksie tussen spesies en geslag is opgemerk vir die verskillende kleinhandelsnitte van gemsbok en koedoe nie. Mikrobiologiese tellings vir wildsvleis, verkoel vir 6 weke en gevries vir 12 maande, onderskeidelik, het voldoen aan die aanvaarbare vlakke soos voorgeskryf deur die Suid-Afrikaanse kleinhandelsmark. Verskille in fisiese, chemiese en mikrobiologiese kwaliteite was opgemerk vir die salami van die verskillende spesies. Springbok salami was mikrobiologies onstabiel. Die belangrikste karaktereienskappe bemerk tydens die proe van die salami vervaardig van springbok-, gemsbok- , koedoe - en sebravleis, was ʼn oorheersende rook-, sout-, peper- en salamigeur, gekombineer met ʼn rook- en salami aroma. Wildsvleisgeur het nie sterk na vore gekom tydens die sensoriese analise, nie. Die volhoubare gebruik van wild vir kommersiële vleisproduksie het die potensiaal om inkomste vir belangegroepe in die wildsektor te verhoog. Resultate van hierdie studie het kennis uitgebrei wat gebruik kan word om die wildsvleisindustrie in Namibië te ontwikkel.

Indigenous chicken production receives little institutional support and resources because of lack of information on the socioeconomic importance, morphometric characteristic and meat quality of indigenous chickens. A cross sectional survey was conducted to highlight the major constraints to production. A structured questionnaire was administered to 126 households selected from communities of Mnambiti-Ladysmith and Impendle local municipalities of KwaZulu-Natal Province of South Africa. The mean flock size per household was 20 and 17 for Mnambiti-Ladysmith and Impendle, respectively. The cock to hen ratio was 1:2:5. The chickens were mostly kept for meat and income ranked 1 and 2 respectively. Generally, adult females made the majority of decisions on chicken management and marketing (61%), with youths playing a minor role. Scavenging was the major feeding system, seasonally supplemented with cereal grain. The majority of the farmers (87%) provided birds with drinking water. Mortality of chickens was prevalent (46%) in both seasons. In experiment 2, the objective of the study was to compare morphometric characteristics of Black Australorp, Potchefstroom Koekoek, Venda and Ovambo chickens. A flock of 200 indigenous chickens, 50 each of Black Australorp, Potchefstroom Koekoek, Venda and Ovambo breeds were reared under semi-intensive system for 22 weeks. The chickens were slaughtered at 22 weeks of age by manual neck cut, bled for 2 minutes and de-feathered. Body weights, organ weights and linear body measure were estimated using flexible tape prior to slaughter. The body weight for the Black Australorp were higher (P<0.05) than the other breeds. There was no significant difference between the lung, heart kidney and spleen weights among breeds. Linear regression revealed that measurements of linear body parts can be used to predict weight of the birds. The objective of Experiment 3 was to compare consumer acceptability of meat from chickens that are indigenous to South Africa compared to Black Australorp and the broiler. A flock of 200 unsexed freely ranging indigenous chickens of Potchefstroom Koekoek, Venda, Black Australorp and Ovambo breeds were reared under an improved semi-intensive system for 22 weeks. The acceptability of cooked meat samples from each breed was rated on a 9 point Hedonic scale by 69 consumer pannellists drawn from the University of KwaZulu-Natal, Cedara College of Agriculture and the Depart of Agriculture. Age of consumer had no effect on all the sensory attributes of the meat evaluated (P> 0.05). Chicken breed had a significant effect on taste and overall acceptability (P< 0.05) with the Venda, Broiler and Black Australorp, but it had no significant difference on colour, texture and aroma acceptability. Gender of the consumer had a significant effect (p<0.01) on taste, colour and texture acceptability of the meat, but no significant effect on aroma and overall acceptability. Female respondents gave lower scores for taste than did the males (P< 0.01). There was no interaction between gender of consumer and chicken breed on meat texture. Crossbreeding the indigenous chickens with improved breeds such as the Black Australorp is one avenue through which sensory characteristics of the indigenous chickens may be improved. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Darbo tikslas: ištirti padidintų geležies sulfato ir geležies glicinato kiekių įtaką viščiukų broilerių produktyvumui ir paukštienos kokybei. Darbo uždaviniai: 1. Ištirti padidintų geležies sulfato ir glicinato kiekių įtaką viščiukų broilerių augimo intensyvumui; 2. Ištirti padidintų geležies sulfato ir glicinato kiekių įtaką viščiukų broilerių lesalų sąnaudoms bei išsaugojimui; 3. Ištirti padidintų geležies sulfato ir glicinato kiekių įtaką viščiukų broilerių skerdenos morfologinei sudėčiai; 4. Ištirti padidintų geležies sulfato ir glicinato kiekių įtaką viščiukų broilerių krūtinėlės ir šlaunelių raumenų pH dinamikai, geležies ir malondialdehido (MDA) kiekių susikaupimui, bei mėsos juslinėms savybėms. Tyrimo metodika: Lesinimo bandymas buvo atliekamas 35 dienas su Ross 308 linijų derinio viščiukais broileriais. Viščiukai broileriai buvo suskirstyti į 3 grupes po 200 viščiukų kiekvienoje grupėje. Pirmoji grupė kontrolinė, likusios – tiriamosios. Kontrolinės grupės viščiukai broileriai buvo lesinami standartiniais kombinuotaisiais lesalais, į kuriuos buvo įterpta 70 mg geležies sulfato. Į I tiriamosios grupės standartinius kombinuotuosius lesalus – 144 mg geležies glicinato, o II tiriamosios grupės lesalus buvo įterpta 150 mg geležies sulfato. Tyrimo rezultatai ir išvados: Analizuojant 35 dienų amžiaus duomenis, abiejuose tiriamosiose grupėse viščiukų broilerių kūno masė padidėjo 1 proc., lyginant su kontroline grupe (p>0,05), o lesalų sąnaudos 1 kg priesvorio gauti... [toliau žr. visą tekstą] / The aim of work (research): investigate the increased quantities of ferrous sulfate and glycinate influence on broiler chickens productivity and poultry meat quality. The tasks of the work: 1. to investigate the increased quantities of ferrous sulfate and glycinate influence to the intensity of broiler chickens’ growth; 2. to investigate the increased quantities of ferrous sulfate and glycinate influence to the input and preservation of broiler chickens’ feed; 3. to investigate the increased quantities of ferrous sulfate and glycinate influence to the morphological composition of broiler chickens’ carcase; 4. to investigate the increased quantities of ferrous sulfate and glycinate influence to the breast and thigh muscle pH dynamics, iron and malondialdehyde (MDA) quantities accumulation and sensory properties of the broiler chickens’ meat. Research methodology: The feeding experiment took 35 days and was performed with the Ross 308 broiler chickens line combination. Broilers were divided into 3 groups of 200 broilers in each. The fowl of all 3 groups were fed with a standard composite feed. The first control group, the rest - the test. The control group of chickens were fed the standard composite feed, containing 70 mg of ferrous sulfate. In the I treatment group compound feeds was added- 144 mg ferrous glycinate, and group II feeds has been added to 150 mg of ferrous sulfate. Broiler chickens were fed ad libitum. Research results and conclusion: Analysis of 3... [to full text]

Thesis (MScVoedselwet)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Two experiments were conducted in order to manipulate the physical and chemical properties and shelf life of ostrich meat. Experiment 1: The effect of dietary fish oil rich in n-3 fatty acids on the organoleptic, fatty acid and physicochemical characteristics of ostrich meat. The diet of four ostrich groups (15 birds per group), approximately 3 months of age (ca. 41 kg live weight) grazing a predominantly oats pasture, was supplemented with a diet containing 6.7% fish oil. The birds received a supplement of either 0 (diet 1), 800 (diet 2), 1600 (diet 3) or 2400 g (diet 4) DM/day resulting in the consumption of 0 (diet 1), 14.5 (diet 2), 29 (diet 3) and 43.5 (diet 4) g fish oil per day. The ostriches were slaughtered at 10 months of age (ca. 70 kg live weight). An increase in the amount of fish oil consumed was found to have had statistically no significant effect on the sensory characteristics of the M. iliofibularis, although there was a tendency towards an increase in ‘fishiness’, for both aroma and flavour. However, increased concentrations of fish oil had a significant effect on the aroma and flavour of the abdominal fat pads. The muscle pHf and muscle lightness (L*) reflected a significant reduction with increased fish oil levels. The increased feed intake, on the other hand, had no effect on the chemical composition (moisture, protein, fat and ash content) of the meat. The fatty acid profile of both fat and meat was affected by the consumption of fish oil. The SFA concentration increased, while the PUFA concentration decreased, with an increase in feed intake. The MUFA concentration remained constant for all four groups. Experiment 2: The effect of dietary vitamin E and the type of packaging on the sensory quality, physicochemical composition and shelf life of ostrich meat. Two groups of ostriches (35 birds per group; ca. 3 months old) were fed diets containing either 40 mg/kg feed vitamin E (control) or 150 mg/kg feed Vitamin E for nine months. The birds were slaughtered at 12 months of age. The effect of different the levels of vitamin E and heat shrink treatment of vacuum packaging material on the shelf life of refrigerated (0°C) ostrich M. flexor cruris lateralis, was evaluated over 81 days. Vitamin E and heat shrink treatments were found to have had no significant effect on the sensory characteristics; off-meat aroma, sourness, juiciness and mealiness. Rancidity was found to be slightly more pronounced (although not statistical significant) in the vitamin E and heat shrink groups than in the feed control and vacuum-packed groups. A significant decrease in the organoleptic quality of the meat, over a 40 day shelf life period, was observed. The pH and muscle tenderness showed a significant reduction with increased storage time. The purge loss in the package increased over time with no change in muscle drip loss. The colour, conjugated dienoic acid and fatty acid content showed no significant changes over time or with regards to treatment. The total viable counts and coliform numbers in the muscle increased over time, with the coliforms being slightly suppressed by the inclusion of vitamin E in the diet. A microbiological safe shelf life of 40 days at 0°C was obtained. / AFRIKAANSE OPSOMMING: Twee eksperimente is uitgevoer om die fisiese en chemiese eienskappe, asook die rakleeftyd van volstruisvleis, te manipuleer. Eksperiment 1: Die effek van visolie, ryk aan n-3 vetsure, op die organoleptiese, vetsuur- en fisies-chemiese eienskappe van volstruisvleis. Die dieet van vier groepe volstruise (15 voëls per groep), ongeveer 3 maande oud (ca. 41 kg lewende massa) wat ‘n hawer weiding bewei het, is aangevul met ‘n byvoedingsmengsel wat 6.7% visolie bevat en in toenemende hoeveelhede vir die groepe volstruise gevoer is. Die voëls het ‘n aanvulling van 0 (dieet 1), 800 (dieet 2), 1600 (dieet 3) of 2400 g (dieet 4) DM/dag ontvang wat gelei het tot ‘n inname van 0 (dieet 1), 14.5 (dieet 2), 29 (dieet 3) en 43.5 (dieet 4) g visolie per dag. Die volstruise is op ‘n ouderdom van 10 maande geslag (ca. 70 kg lewende massa). ‘n Toename in die hoeveelheid visolie ingeneem, het geen statisties betekenisvolle effek op die sensoriese eienskappe van die M. ilifibularis gehad nie, alhoewel daar ‘n tendens was vir ‘n toename tot ‘n ‘visagtige’ aroma en smaak. ‘n Toename in die konsentrasie visolie het egter ‘n betekenisvolle effek op die ‘visagtige’ aroma en smaak van die abdominale vet neerslae gehad. Die spier pHf en spier ligtheid (L*) het ‘n betekenisvolle afname met toename in voer inname getoon. Die verhoogde olie inname het egter geen effek op die chemiese samestelling (vog-, proteïen-, vet- en asinhoud) van die vleis gehad nie. Die vetsuurprofiel van beide die abdominale vet neerslae en die vleis is deur die inname van visolie verander. Die versadigde vetsuurkonsentrasie het verhoog terwyl die poli-onversadigde vetsuurkonsentrasie verlaag het met ‘n toename in rantsoenvlakke. Die mono-onversadigde vetsuurkonsentrasie het egter konstant gebly vir al vier groepe. Eksperiment 2: Die effek van vitamien E en die tipe verpakking op die sensoriese kwaliteit, fisies-chemiese samestelling en rakleeftyd van volstruisvleis. Twee groepe volstruise (35 voëls per groep, ongeveer 3 maande oud) het voere oor ‘n tydperk van nege maande ontvang wat 40 mg vitamien E/kg voer (kontrole) of 150 mg vitamien E/kg voer bevat het. Die voëls is op 12 maande ouderdom geslag. Die effek van die verskillende vlakke van vitamien E en hitte-behandeling van die verpakkings materiaal op die rakleeftyd van verkoelde (0°C) volstruis M. flexor cruris lateralis, is oor 81 dae geëvalueer. Vitamien E en die hitte-behandeling het geen betekenisvolle effek op die organoleptiese eienskappe (af-vleis aroma, suurheid, sappigheid en melerigheid) gehad nie. Galsterigheid was ‘n bietjie meer gedefinieerd (anie-betekenisvol) in die vitamien E en hitte behandelde groepe as in die rantsoen kontrole en vakuum verpakte vleis. ‘n Betekenisvolle afname is waargeneem in die organoleptiese kwaliteit van die vleis oor ‘n 40 dae rakleeftyd periode. Die pH en taaiheid van die spier het betekenisvol afgeneem met ‘n toename in bergingsperiode. Die drup verlies tydens verpakking het ook oor tyd toegeneem, terwyl geen verandering in die analitiese drup verlies van die spier verkry is nie. Die kleur, gekonjugeerde dieensuur en vetsuursamestelling het geen verandering oor tyd of ten opsigte van behandeling getoon nie. Die Totale Lewendig Seltelling en coliforme het toegeneem oor tyd, terwyl die coliforme deur die byvoeging van vitamien E tot ‘n mate onderdruk is. ‘n Mikrobiologies veilige rakleeftyd van 40 dae is verkry.

Thesis (MSc Consumer Science)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Please see fulltext for abstract / AFRIKAANSE OPSOMMING: Sien asb volteks vir opsomming

Thesis (MA)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Meat processing industries in South Africa are faced with the challenge to produce a variety of white meats. This is due to the fact that consumers tend to consume less red meat and more chicken and pork that are perceived to be healthier due to the negative publicity surrounding red meat and health. The nutritional emphasis is on leaner carcasses and an increase in the consumption of polyunsaturated fatty acids while reducing the ratio of n-6:n-3 polyunsaturated fats in the diet. Another way in which this can be achieved is through introducing rabbit meat which has low fat, low cholesterol content and high protein content, while displaying a positive fatty acid profile. Carcass quality and meat quality in rabbits may to a large extent be affected by age of slaughter and type of breed. This study had a dual purpose. Firstly it aimed at quantifying the effects of breed and age on parameters pertaining to carcass quality and meat quality of commercial rabbits, namely California breed and hybrid (California x Dutch red). Secondly, to determine the differences between ethnic groups on their perceptions towards rabbit meat, thereby providing information on its marketing potential. To accomplish the first objective 50 rabbits from the two breeds were housed in individual cages, weighed on weekly basis and fed ad libitum. The rabbits were slaughtered at 9, 11, 13, 15 and 17 weeks of age (n=5 from each breed). For the second objective the perceptions of three ethnic groups on factors affecting consumers' choice of rabbit meat were determined through a structured questionnaire. The questionnaire was tested for validity beforehand. There was no significant difference between the two breeds regarding body weight, feed intake, carcass weight and drip loss. The California breed had a higher dressing percentage (53.7%) and meat yield (29.2%) compared to the hybrid (52.5% and 27.5% respectively). Age treatments showed a highly significant difference on all parameters investigated. Increasing the age proportionately increased the amount of fat, while the moisture content decreased. The California breed exhibited higher percentages of fat compared to the hybrid at all ages of treatment. California breed contained more phosphorus, magnesium and zinc as opposed to the hybrid, the only exception being copper, where the hybrid had higher concentrations. The total fatty acid (169.2 mg/100 g) of the California breed was higher than that of the hybrid (133.5 mg/100 g). As a result there were more saturated fatty acids (55.4 mg/100 g) and monounsaturated fatty acids (62.3 mg/100 g) in the California breed than in the hybrid (44.2 and 45.6 mg/100 g respectively). Both breeds had 67% unsaturated fatty acids. Although there was no significant difference between the P:S ratio of the two rabbit breeds, the values obtained were higher (+0.9) than the value of 0.7. This is an indication that the rabbit meat contains a P:S ratio that could be considered very desirable. The n-6:n-3 ratio for both breeds were high (11.6 for California and 12.7 for hybrid). The cholesterol and amino acid profile of the two breeds were not affected by the type of breed. The consumer survey indicated that 52% (n=158) of respondents had never eaten rabbit meat before due to reasons such as scarcity, lack of knowledge about the meat, associating rabbits with pets and cultural constraints. Nevertheless, 57% of these people were optimistic about eating rabbit meat. In addition, having eaten rabbit meat before seemed to contribute positively towards acceptance of rabbit meat. Generally, respondents preferred purchasing rabbit meat in portions as opposed to live or whole carcasses. Their decision to purchase rabbit meat was firstly driven by price, thereafter freshness, leanness and tenderness of meat. The respondents expect to buy rabbit meat at a price lower than that of chicken. Rabbit meat contained low sodium and high proportion polyunsaturated fatty acids-some of the most important food attributes required to maintain and improve health. However, most of the respondents in this study were not familiar with the positive attributes of rabbit meat and need to be taught the benefits of this product. / AFRIKAANSE OPSOMMING: In Suid Afrika is daar 'n uitdaging vir die vleisproduserende voedselindustrieë om 'n verskeidenheid witvleis te bemark. Dit word toegeskryf aan die feit dat verbruikers minder rooi vleis as hoender en vark eet wat as meer gesond beskou word weens die negatiewe publisiteit wat geassosieer word met rooivleis en gesondheid. Die voedingsfokus is op maerder karkasse, groter inname van polionversadigde vetsure, en 'n vermindering in die verhouding n-6:n-3 poli-onversadigde vetsure in die dieet. Een van die maniere waarop dit gedoen kan word, is die bekendstelling van konynvleis wat gekenmerk word deur lae vetinhoud, lae cholesterolinhoud en 'n hoë proteïninhoud, en 'n positiewe vetsuurprofiel. Karkas- en vleiskwaliteit van konyne word tot 'n groot mate geaffekteer deur ouderdom van slagting en die ras. Hierdie studie het 'n tweeledige doel. Eerstens mik dit na die kwantifisering van die effek van ras en ouderdom op die parameters wat met karkas- en vleiskwaliteit van die Kaliforniese ras en die kruisgeteëlde ras (Kaliforniese X Hollandse rooi) verband hou. Tweedens, om die verskille in etniese groepe vas te stel met betrekking tot hulle persepsies van die faktore wat hulle keuse van konynvleis beïnvloed, en op dié wyse inligting te verkry t.o.v die bemarkingspotensiaal daarvan. Om in die eerste doelwit te slaag is 50 konyne van die twee rasse in individuele hokke gehuisves, op 'n weeklikse basis geweeg en ad libitum gevoer. Die konyne was geslag op 9, 11, 13, 15 en 17 weke (n=5 vir elke ras). Vir die tweede doelwit, is die persepsies van drie etniese groepe oor die faktore wat die verbruikerskeuse van konynvleis kan bepaal, m.b.v. 'n gestruktureerde vraelys bepaal. Die vraelys is vooraf vir geldigheid evalueer. Daar was geen beduidende verskil tussen die twee rasse wat betref liggaamsmassa, voedselinname, karkasgewig en dripverlies nie. Die Kaliforniese ras het 'n hoër uitslag-persentasie (53.7%) en vleisopbrengs (29,2%) in vergelyking met die kruisgeteëlde ras (52.5% en 27.5% respektiewelik) gehad. Ouderdom het hoogsbeduidende verskille op al die parameters wat ondersoek was, getoon. Die toename in ouderdom was gepaardgaande met proporsionele toename in karkasvet en afname in vog. Die Kaliforniese ras het, by alle ouderdomsbehandelings, in vergelyking met die kruisgeteëlde ras, 'n hoër persentasie vet opgelewer. Die Kaliforniese ras het teenoor die kruisgeteëlde ras hoër fosfor, magnesium en sink bevat. Die uitsondering was koper waar die kruisgeteëlde ras 'n hoër waarde gehad het. Die totale vetsure vir die Kaliforniese ras (169.2 mg/100 g) was hoër as vir die kruisgeteëlde ras (133.5 mg/100 g). Om dié rede was daar in die Kaliforniese ras meer versadigde vetsure (55.4 mg/100 g) en monoonversadigde vetsure (62.3 mg/100 g) as vir die kruisgeteëlde ras (44.2 mg/100 g en 45.6 mg/100g onderskeidelik). Beide rasse het 67% onversadigde vetsure gehad. Hoewel daar geen beduidende verskille was in die polionversadigde:versadigde (P:V) verhouding nie, was die waardes hoër (+0.9) as die 0.7 wat aanbeveel word. Die n-6:n-3 verhouding vir beide rasse was hoog (11.6 vir die Kaliforniese ras en 12.7 vir die kruisgeteëlde ras). Die cholesterol- en die aminosuurprofiel was nie deur die ras beïnvloed nie. Die verbruikersnavorsing het getoon dat 52% (n=158) van die respondente om verskeie redes nog nie konynvleis geëet het nie, weens redes soos onverkrygbaarheid, gebrekkige kennis van die vleis, die assosiasie van konyne met troeteldiere en kulturele beperkinge. Desnieteenstaande is daar 57% van die respondente wat optimisties is oor die eet van konynvleis. Die eet van konynvleis by vorige geleenthede het bygedra tot die positiewe aanvaarding van konynvleis. Oor die algemeen het die respondente verkies om konynvleis in porsies te koop, in plaas van lewendig of heel karkasse. Die besluit om konynvleis te koop, is hoofsaaklik gedryf deur prys, daarna deur varsheid, maerheid en sagtheid van die vleis. Die respondente verwag dat die prys vir konynvleis laer sal wees as vir hoender. Konynvleis bevat lae natrium en 'n hoë verhouding poli-onversadigde vetsure - van die mees belangrike voedingeienskappe om gesondheid te handhaaf en te verbeter. Ongelukkig was meeste van die respondente in hierdie studie nie vertroud met die positiewe eienskappe van konynvleis nie, en moet hulle geleer word deur middel van omvattende bemarkingsaksies van die voordele van hierdie produk.

Thesis (MSc)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: The objectives of this study were threefold: (i) to investigate the effect of the replacement of pork fat with olive oil on the physico-chemical and sensory characteristics of ostrich polony; (ii) to investigate the effect of replacement of sodium tri-polyphosphate (STPP) with iota-carrageenan (CGN) on the physico-chemical and sensory characteristics of restructured cooked ostrich ham; and (iii) to investigate the effect of salt (NaCl) reduction on the physico-chemical and sensory characteristics of ostrich bacon. Five levels of olive oil were added to a polony formulation in 5% increments from 0 to 20%. Hardness, gumminess and shear force values decreased (P≤0.05) with increased levels of olive oil. The L* and b* values decreased (P≤0.05) with increased levels of olive oil producing lighter and more yellow products. Ostrich polony proved to have a favourable fatty acid profile in line with international recommended standards. A trained sensory panel found that the effect of increased levels of olive oil on had an effect (P≤0.05) on the sensory characteristics of colour; processed meat aroma and flavour; ostrich aroma; olive oil aroma; firmness and juiciness. A consumer panel found all the olive oil treatments to be acceptable. It can be concluded that olive oil can be used successfully for the production of low fat ostrich meat polony. In a restructured ostrich ham five decreasing levels of phosphate (0.7, 0.53, 0.35, 0.18 and 0%) were substituted with five increasing levels of carrageenan (0, 0.1, 0.2, 0.3 and 0.4%). The cooked yield of the restructured ostrich ham decreased significantly (P≤0.05) with decreased levels of phosphate. No tendencies in instrumental colour measurements with relation to decreased levels of phosphate were revealed. Hardness, cohesiveness and gumminess increased with decreased levels of phosphate. Ostrich ham had a favourable fatty acid profile and the latter is in line with international recommended standards. The trained sensory panel found that decreased levels of phosphate had a significant effect on the ham sensory characteristics of meat aroma and flavour; ostrich meat aroma and flavour and mealiness, but no significant effect on the spicy aroma and flavour. Three ham treatments with different levels of phosphate (0.7, 0.35 and 0%) were presented to a consumer panel. The consumer panel found the ham treatments with levels of 0.7 and 0.35% most acceptable. Carrageenan can be used to substitute phosphate at a level of 0.35% phosphate and 0.2% carrageenan in ostrich ham. Ostrich bacon was produces with five targeted salt (NaCl) levels of 3.5, 2.75, 2.0, 1.25, and 0.5%. Decreased salt levels had no significant effect on the L*, a* and b* values of the five treatments. Ostrich bacon had a favourible fatty acid profile. A trained sensory panel found that the effect of increased levels of salt had a significant effect on bacon sensory characteristics of ostrich aroma and flavour smoky bacon aroma and flavour and saltiness. A consumer panel found all the bacon treatments acceptable, with 2.75 and 2.0% being most likable. It can be concluded that, from a technical point of view, the salt content in ostrich bacon can be reduced successfully to produce ostrich bacon with low salt levels, although consumer preference for salt remains high. / AFRIKAANSE OPSOMMING: Die doelstellings van hierdie studie was drievoudig: (i) om die effek van die vervanging van varkvet met olyfolie op die fisiko-chemiese en sensoriese eienskappe van volstruispolonie te bestudeer; (ii) om die effek van die vervanging van natriumtripolifosfaat met iotakarrageenan op die fisikochemiese en sonsoriese eienskappe op die van hergestruktureerde volstruisham te bestudeer; en (iii) om die effek van sout (NaCl) vermindering op die fisiko-chemiese en sensoriese eienskappe van volstruisspek te bestudeer. Die polonie behandelings het uit vyf vlakke olyfolie bestaan wat by die polonie formulasie in 5% inkremente 0% tot 20% gevoeg is. Hardheid, taaiheid en skeurkrag het afgeneem (P≤0.05) met verhoogde vlakke van olyfolie. Die L*- en b*-waardes het afgeneem (P≤0.05) met verhoogde vlakke van olyfolie en uiteibdelik ‘n ligter en geler produk geproduseer. Die betrokke volstruispolonie behandelings het ‘n gunstige vetsuurprofiel wat in lyn is met internasionale aanbevole standaarde. ‘n Opgeleide sensoriese paneel het gevind dat die verhoogde vlakke van olyfolie ‘n betekenisvolle (P≤0.05) effek het op die kleur, geprossesseerde vleisgeur en -aroma, volstruis aroma, olyfolie aroma, fermheid en sappigheid. ‘n Verbruikerspaneel het gevind dat al vyf polonie behandelings aanvaarbaar is. Olyfolie kan dus suksesvol gebruik word in die produksie van laevet volstruispolonie. Hergestruktureerde volstruisham het bestaan uit vyf afnemende fosfaat vlakke (0.7, 0.53, 0.35, 0.18 and 0%) en vyf toenemende vlakke van karrageenan (0, 0.1, 0.2, 0.3 and 0.4%). Die opbrengs van gaar hergestruktureerde volstruisham het afgeneem (P≤0.05) met verlaagde vlakke van fosfaat. Geen betekenisvolle patroon is in instrumentele kleurmeting gevind nie. Hardheid, binding en taaiheid het toegeneem met afnemende fosfaat vlakke. Daar is bewys dat volstruisham ‘n gunstige vetsuurprofiel het wat in lyn is met internasionale aanbevole standaarde het. ‘n Opgeleide sensoriese paneel het gevind dat afnemende fosfaatvlakke ‘n betekenisvolle effek op die sensoriese eienskappe van volstruisvleis geur en aroma asook melerigheid, maar geen betekenisvolle effek op die speserygeur en -aroma gehad nie. Drie behandelings met verskillende fosfaat vlakke (0.7, 0.35 and 0%) is deur ‘n verbruikerspaneel vir aanvaaraarheid getoets. Die verbruikerspaneel het gevind dat die behandelings met 0.7 en 0.35% fosfaat aanvaarbaar was. Karrageenan kan dus gebruik word om fosfaat te vervang by ‘n vlak van 0.35% fosfaat en 0.2% karrageenan in volstruisham. Volstruisspek is geproduseet met vyf soutvlakke (NaCl), nl 3.5, 2.75, 2.0, 1.25 en 0.5%. Verlaagde soutvlakke het geen beteknisvolle effek op die L*-, a*- en b*-waardes van die vyf behandelings gehad nie. Volstruisspek het ook ‘n besonder gunstige vetsuurprofiel. ‘n Opgeleide sensoriese paneel het gevind dat die effek van verhoogde soutvlakke ‘n betekenisvolle effek het op die volgende sensoriese eienskappe: geur en aroma van volstruisvleis; geur en aroma van gerookte spek; en southeid. ‘n Verbruikerspaneel het gevind dat al die behandelings aanvaarbaar was, met die monsters met 2.75 and 2.0% sout as mees aanvaarbaar. In opsomming, die soutinhoud van volstruisspek kan uit ‘n tegniese oogpunt suksesvol verlaag word om ‘n produk met ‘n laer soutinhoud te produseer, alhoewel verbruikersvoorkeur vir sout hoog bly.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The present study aimed to evaluate the performance, carcass characteristics, the fatty acid profile and meat quality of lambs fed increasing levels of grape pomace silage replacing alfalfa. We used 24 not castrated Texel lambs, with an average weight of 24.5 kg and a mean age of 100 days, randomly distributed in a completely randomized design with four treatments and six replications. The treatments consisted of increasing levels of grape pomace silage (SBU) of 0%, 15%, 30% and 50% on a full ration. Observed effect of inclusion level of SBU consumption of dry matter, crude protein, total digestible nutrients (P <0.01) decreased as the inclusion level of SBU increased. A quadratic effect of inclusion levels of SBU on consumption of lipids (CEE) (P <0.01) was observed. The use of neutral detergent fiber and feed conversion was not affected by inclusion level of dietary SBU. The inclusion level of SBU in the diets affected (P <0.01) the average daily weight gain, which decreased with increasing dietetic SBU, presenting average values of 268, 251, 235 and 213g for levels: 0 , 15, 30 and 50% of SBU inclusion in the diet, respectively. There was no effect (P> 0.05) in the level of inclusion of SBU carcass characteristics, weights of body components and weights and proportions of commercial cuts of lambs. It was observed (P <0.01) that the level of inclusion of SBU has promoted an increasing of linoleic acid (C18: 2n6c) concentration in Longissimus dorsi muscle. It was also observed increase in the content of polyunsaturated fatty acids (P <0.05). Moreover, the ratio between polyunsaturated fatty acids to saturated (P: S) was improved to values of 0.179, 0.192, 0.226 and 0.227 (P <0,05), respectively as the SBU was increased. However, the increase of SBU promoted increasing (P <0.01) of the content of omega 6 (n-6) in relation to the content of omega 3 (n6: n3) presenting ratios of 3.16, 4.85, 6.39, 6.82, respectively for levels of 0, 15, 30 and 50% of SBU tested. The softness, cholesterol, pH and chemical composition of muscle tissue were not affected (P> 0.05) by the level of SBU. As a result, it can be concluded that the grape pomace silage is an alternative source of nutrients for lambs and can be used as a substitute for good quality hay, for providing satisfactory performance, without carcass characteristics and body components alteration, producing a healthier meat for human consumption due to the increase of polyunsaturated fatty acids content. / O presente estudo teve por objetivo avaliar o desempenho, as características da carcaça, o perfil de ácidos graxos e a qualidade da carne de cordeiros alimentados com níveis crescentes de silagem de bagaço de uva em substituição à alfafa. Foram utilizados 24 cordeiros machos, não castrados, raça Texel, com média de peso vivo de 24,5 kg e idade média de 100 dias, distribuídos aleatoriamente em um delineamento inteiramente casualizado com quatro tratamentos e seis repetições. Os tratamentos foram constituídos por níveis crescentes de silagem de bagaço de uva (SBU) de 0%, 15%, 30% e 50% numa ração completa. Observou-se efeito do nível de inclusão de SBU no consumo de matéria seca, proteína bruta, nutrientes digestíveis totais (P<0,01) que decresceram à medida que se aumentou o nível de inclusão de SBU. Houve efeito quadrático de níveis de inclusão de SBU sobre o consumo de extrato etéreo (CEE) (P<0,01). O consumo de fibra em detergente neutro e a conversão alimentar não foram afetados pelo nível de inclusão de SBU na dieta. O nível de inclusão de SBU nas dietas influenciou (P<0,01) o ganho de peso médio diário, que diminuiu com o aumento de SBU na dieta, apresentado valores médios de 268, 251, 235 e 213g para os níveis de: 0, 15, 30 e 50% de inclusão de SBU na dieta, respectivamente. Não foi observado efeito (P>0,05) do nível de inclusão de SBU nas características de carcaça, pesos dos componentes corporais e pesos e proporções dos cortes comerciais da carcaça dos cordeiros. Foi observado efeito (P<0,01) do nível de inclusão de SBU no percentual do ácido linoleico (C18:2n6c) depositado no músculo Longissimus dorsi, havendo incremento deste ácido com o aumento do nível de inclusão de SBU. Também se observou aumento no teor de ácidos graxos poli-insaturados (P<0,05) e relações entre ácidos graxos poli-insaturados e saturados (P:S) mais favoráveis, de 0,179; 0,192; 0,226 e 0,227 (P<0,05), respectivamente, na medida em que se aumentou a inclusão de SBU. No entanto, o aumento de SBU promoveu incremento (P<0,01) no teor de ácidos graxos ômega 6 (n-6) em relação ao teor de ômega 3 (n6:n3) apresentando razões de 3,16; 4,85; 6,39; 6,82, respectivamente para os níveis de 0 a 50% de SBU testados. A maciez, o colesterol, o pH e a composição centesimal do tecido muscular não foram influenciados (P>0,05) pelo nível de SBU. A silagem de bagaço de uva é uma fonte alternativa de nutrientes para cordeiros, podendo ser utilizada em substituição a forragens de boa qualidade, pois proporcionou desempenho satisfatório, não alterou as características da carcaça e componentes corporais e produziu uma carne mais saudável ao consumo humano por aumentar o teor de ácidos graxos poli-insaturados.

Orientador: Hirasilva Borba Alves de Souza / Banca: Alexandre Oba / Banca: Vera Maria Barbosa de Moraes / Resumo: Esse experimento objetivou avaliar o desempenho, rendimento de carcaça e características qualitativas da carne do peito de frangos de corte alimentados com dietas suplementadas com diferentes concentrações (0,3 e 0,5 mg/kg de ração) e fontes (orgânica e inorgânica) de Selênio, sendo o Sel-Plex TM e o selenito de sódio as fontes utilizadas. Utilizou-se 1050 aves (machos), que receberam rações isoproteicas e isoenergéticas em todas as fases de criação (1 a 21, 22 a 35 e 36 a 42 dias). Foi utilizado o esquema fatorial 2X2 + 1 (2 concentrações X 2 fontes de Se + controle) em delineamento inteiramente casualizado, com 5 tratamentos e 7 repetições, com 30 aves por parcela. A viabilidade foi melhorada com a suplementação da ração com Selênio, independente da fonte utilizada. No período de 1 a 21 dias, a suplementação melhorou o desempenho das aves, através de menor conversão alimentar.Porém, nos períodos de 1 a 35 e 1 a 42 dias o consumo de ração e o ganho de peso pioraram com a suplementação. Das fontes utilizadas, a orgânica promoveu melhora significativa no desempenho das aves em todos os períodos, sendo que os melhores resultados foram obtidos com a concentração de 0,5 mg de Se/kg de ração. Nenhum dos fatores influenciou o rendimento de carcaça e cortes. A utilização da fonte orgânica ao invés da inorgânica diminuiu a taxa de oxidação da carne do peito das aves armazenada por 7 e 15 dias a 4ºC, além de ocasionar menor luminosidade e maior pH. Houve influência das fontes e das concentrações sobre a deposição de selênio na carne, sendo a fonte orgânica superior à inorgânica e o nível de 0,5 superior ao de 0,3 mg de Se/kg de ração. A concentração de 0,5 mg de Se/kg de ração na dieta proporcionou aumento da porcentagem de cinzas na carne. / Abstract: This study was conducted to evaluate the effect of different concentrations (0,3 and 0,5 mg/kg) and sources (organic and inorganic) of selenium on performance, carcass and parts yield and breast meat quality of broilers (Cobb 500). 1050 one-day-old male chicks were distributed in a completely randomized design in a 2x2+1 factorial arrangement (2 concentrations, 2 sources and 1 control diet), with 7 repetitions per treatment and 30 birds per replicate. The experiment lasted 42 days and the diet for each phase (1-21, 1-35 and 1-42 days) were corn-soybean meal based. The results showed better viability when the supplemented diets were used, independent of the source. In the first period (1 to 21 days), the supplementation provided an improvement on performance, with better feed conversion. However, the results were different in the others breeding phases (1 - 35 and 1 - 42 days), with decrease (P<0,05) on feed intake and weight gain when the supplementation was used. The organic source (Sel-Plex®) provided better results when offered in the second concentration (0,5 mg/kg). None of the factors influenced the carcass and parts yields. The organic source provided a significant decrease in the meat oxidation when it was stored for 7 and 15 days (4ºC). The lightness tended to decrease and the pH tended to increase when the Se-enriched-yeast (Sel-Plex®) was used. There were source and concentration effects on the meat selenium deposition, being the organic source better than the inorganic source (sodium selenite) and the second concentration (0,5 mg/kg) better than the first (0,3 mg/kg).The concentration of 0,5 mg/kg provided increase of the percentage of ashes in the meat. / Mestre