Made available in DSpace on 2017-07-10T17:48:30Z (GMT). No. of bitstreams: 1 Flavia_Renata_Potrich.PDF: 766462 bytes, checksum: d0486b8e222c0730ab0ffe2a72206571 (MD5) Previous issue date: 2012-04-20 / Two experiments were conducted to evaluate the effect of organic soybean meal (FSO) and conventional soybean meal (FSC) on digestibility and performance of Nile tilapia fingerlings. For the digestibility experiment, 90 Nile tilapia with average weight of 184.16 ± 22.79 g, were distributed in six 180-liter conic tanks in a digestibility system, with constant aeration through blower central air and heating water by thermostat. Three diets were prepared, a reference and two test diets. For the preparation of test diets (organic and commercial soybean meal) were used 70% of the basal diet and 30% of the test ingredients inclusion. Chromic oxideIII was used as inert indicator in proportion of 0.1%. Modified Guelph was used to fecal collection method. For the growth performance experiment, 400 Nile tilapia juvenile were used with an average initial weight of 12.7 ± 0.36 g and 9.2 ± 0.30 cm in length,. Fish were entirely randomized into twenty 500-liter fiberglass tanks, with five treatments and four replications. Four diets were formulated with 32% of crude protein (FSO, FSC, FSO + 20% fish meal (FSO+FP), FSC + 20% fish meal (FSC+FP) and a commercial diet with 32% of crude protein (COM)). The average final weight was evaluated, as well as weight gain, average daily gain, final length, survival, apparent feed conversion, condition factor, hepatosomatic index, visceral fat and carcass chemical composition (dry matter, lipids, protein and mineral matter). Hematologic parameters (erythrocyte, hematocrit and hemoglobin); hematimetrics (mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration); and biochemical parameters (cholesterol, triglycerides, albumin and total protein), were analyzed. The apparent digestibility coefficient of protein were 88.24 and 88.10% resulting in 39.91 and 39.87% of digestible protein for FSO and FSC, respectively. The apparent digestibility coefficient of energy was 75.92 and 70.48%, resulting in 3579.46 and 3141.44 kcal/kg of digestible energy for FSO and FSC, respectively, differing from each other by ANOVA test. Fish fed with diet containing FSC+FP showed the best results of final weight, weight gain and daily weight gain. However, the highest carcass levels of crude protein were verified in fish fed with diet containing FSC+FP. As for the blood parameters, fish fed FSO showed better results in comparison to fish fed with other protein sources. The organic soybean meal offered optimal apparent digestibility coefficient and its use in Nile tilapia diets showed satisfactory growth performance and increased protein deposition in the carcass when it included 20% of fishmeal in the diet / Foram conduzidos dois experimentos objetivando avaliar o efeito do farelo de soja orgânico (FSO) e farelo de soja convencional (FSC), sobre a digestibilidade e desempenho de alevinos de tilápia do Nilo. Para o experimento de digestibilidade, foram utilizadas 90 tilápias do Nilo com peso médio de 184,16 ± 22,79 g, distribuídas em seis cubas de 180 litros com fundo cônico, aeração constante por meio de soprador de ar central e sistema de aquecimento da água por termostato. Foram elaboradas três rações, uma ração referência e duas rações testes. Para as rações testes (farelo de soja orgânico e comercial) foram utilizados 70% da ração referência e 30% de inclusão do alimento avaliado. Foi utilizado óxido de cromioIII como indicador inerte na proporção de 0,1% na ração. O sistema adotado para coleta das fezes foi Guelph modificado. Para o experimento de desempenho produtivo, foram utilizados 400 juvenis de tilápias do Nilo com peso inicial médio de 12,7±0,36 g e comprimento médio de 9,2±0,30 cm. Os peixes foram distribuídos aleatoriamente em 20 caixas de fibra de vidro, com volume de 500 litros, com cinco tratamentos em quatro repetições. Foram formuladas quatro rações com 32% proteína bruta (FSO, FSC, FSO + 20% de farinha de peixe (FSO+FP), FSC+ 20% de farinha de peixe (FSC+FP)) e uma ração comercial com 32% de proteína bruta (COM). Foi avaliado o peso final médio, ganho de peso, ganho de peso diário, comprimento final, sobrevivência, conversão alimentar aparente, fator de condição, índice hepatossomático, gordura visceral e composição química dos peixes inteiros (matéria seca, lipídeos, proteína bruta e matéria mineral). Foram avaliados os parâmetros hematológicos (eritrócitos, hematócrito e hemoglobina), hematimetricos (volume corpuscular médio (VCM), hemoglobina corpuscular media (HCM) e concentração de hemoglobina corpuscular média (CHCM), e parâmetros bioquímicos (colesterol, triglicerídeos, albumina e proteínas totais). O coeficiente de digestibilidade aparente da proteína foi de 88,24 e 88,10%, resultando em 39,91 e 39,87% de proteína digestível para o FSO e FSC, respectivamente. O coeficiente de digestibilidade aparente da energia foi de 75,92 e 70,48%, resultando em 3579,46 e 3141,44 kcal/kg de energia digestível para o FSO e FSC, respectivamente, diferindo entre si pela ANOVA. Os peixes que receberam a dieta contendo (FSC+FP) apresentaram os melhores resultados de peso final, ganho de peso e ganho de peso diário. Contudo, os maiores teores de proteína bruta no peixe inteiro foram para os peixes alimentados com a dieta contendo (FSO+FP). Quanto aos parâmetros sanguíneos, os peixes alimentados com FSO apresentaram os melhores resultados de albumina e proteínas totais. O farelo de soja orgânico apresenta ótimo coeficiente de digestibilidade aparente e sua utilização em rações para tilápia proporciona desempenho produtivo satisfatório e maior deposição proteica na carcaça quando as rações são suplementadas com 20% de farinha de peixe

O presente trabalho de pesquisa foi conduzido no período de outubro de 2007 a março de 2008 na Estação de Avaliação de Suínos em Tanquinho, Piracicaba SP, no Frigorífico BRESSIANI®, localizado na cidade de Capivari SP, e as avaliações bioquímicas, químicas, quantidade e qualidade de carne foram realizadas no mês de março a abril de 2008, no Centro de Pesquisa e Desenvolvimento de Carnes do Instituto de Tecnologia de Alimentos, localizado na cidade de Campinas SP. Neste experimento foram testados métodos de castração de suínos objetivando avaliar a incidência do odor de macho inteiro, causado pela androstenona e escatol, presentes no tecido adiposo dos suínos machos, composição corporal e da carcaça. Entre os métodos de castração de suínos machos existentes, foram avaliados o cirúrgico e imunológico. O primeiro consistiu na remoção cirúrgica das gônadas do leitão entre 3 a 5 dias de vida e o segundo na aplicação de duas doses da forma modificada do Fator de Liberação das Gonadotropinas (GnRF) em um sistema coadjuvante de baixa reatividade, sendo a primeira dose aplicada nos animais com 15 semanas e a segunda dose com 19 semanas de idade. Após duas semanas da segunda dose foram coletadas amostras de sangue para avaliação de testosterona através de radioimunoensaio. No momento do abate foi realizada a coleta de parte do tecido adiposo para análise de androstenona e escatol. Nas meias carcaças esquerdas foram avaliadas a qualidade de carne (pH, temperatura, capacidade de retenção de água, perda por exsudação e cor) e a quantidade (medidas lineares das carcaças e rendimentos dos cortes anatômicos). A vacinação dos animais contra o GnRF demonstrou sua eficiência em controlar os compostos responsáveis pelo odor sexual (androstenona e escatol) e em manter os níveis de testosterona comparáveis aos animais castrados cirurgicamente. A imunocastração melhorou o desempenho zootécnico e contribuiu para aumentar a quantidade de carne por animal (4,84 kg), diminuir a de gordura (1, 54 kg) e acrescentar mais carne nos cortes de maior valor comercial, como pernil (1060 g, p < 0,05), carre(400 g, p > 0,05), a barriga (840 g, p < 0,05) e paleta (1460 g, p < 0,05), que representa uma vantagem econômica para a indústria da carne, pois atende os mercados de carne fresca e de produtos industrializados (cozidos e embutidos). Em relação à avaliação sensorial foram constatadas diferenças significativas (p < 0,05) para todos os atributos sensoriais avaliados em favor dos suínos imunocastrados quando comparados com os castrados cirurgicamente. Quanto à preferência, os bifes cozidos de lombo dos suínos imunocastrados obtiveram melhor preferência (66%) em comparação com os castrados cirurgicamente (34%). A intenção de compra também foi em favor dos suínos imunocastrados e refletiu os resultados dos testes de preferência e de aceitação. A maioria dos consumidores (74,8%) provavelmente (20,2%) ou certamente (54,6%) compraria a carne dos suínos imunocastrados e somente 58,4% dos consumidores provavelmente (25,2%) ou certamente (33,2%) compraria a carne dos suínos castrados cirurgicamente. A gordura total encontrada no lombo nesse experimento foi 14.67 e 12.67 g/100g para o grupo dos suínos castrados cirurgicamente e imunocastrados, respectivamente. O rendimento de cocção e os valores da força máxima de cisalhamento (Warner - Bratzler) dos suínos castrados cirurgicamente e imunocastrados não foram estatisticamente diferentes (p > 0,05) enquanto que a cor instrumental (L*, a* e b*) apresentou diferença estatística (p < 0,05) na sua composição para os tratamentos estudados. Os resultados desse trabalho permitem dizer que a imunocastração demonstrou ser eficiente em prevenir o odor sexual bem como em melhorar o desempenho zootécnico e qualidade de carcaça quando comparada com a castração cirúrgica. Quanto à qualidade de carne dos suínos imunocastrados ficou evidenciado que essa tecnologia pode melhorar os atributos sensoriais e outras características de qualidade realizadas nessa pesquisa. / The present study was carried out from October 2007 to March 2008 at the Pig Evaluation Station in Tanquinho, located in Piracicaba city, São Paulo state, in the BRESSIANI® abattoir, located in Capivai, city, São Paulo state, and the biochemical, chemical, meat quantity and meat quality assessments were carried in March 2008, at the Meat Center for Research and Development in the Institute of Food Technology, located in Campinas city, São Paulo state. In this experiment were tested castration methods applied in pigs to evaluate the incidence of the boar taint, caused by androstenone and skatole located in the fat of boars, carcass composition and meat quality. The castration methods tested were physical and immunological. In the first one pig gonads were removed physically at the age 3 to 5 days and the last one the pigs were immunocastrated (two doses, 15 and 19 weeks of age) against the modified factor gonadotropin-releasing (GnRF). After two weeks of the second dose blood samples were taken to evaluate testosterone using radioimmunoassay. At the slaughter level a portion of backfat was collected to assess androstenone and skatole. Meat quality (pH, temperature, water holding capacity, loss of weeping and color) and quantity (linear measurements of carcasses and anatomical cuts yield) were performed at left carcass side. Vaccination of animals against GnRF demonstrated its effectiveness in controlling the boar taint compounds (androstenone and skatole) and to maintain the levels of testosterone comparable to physically castrated animals. The immunocastration improved growth performance and contributed to increase the total meat quantity per animal (4.84 kg), reducing the fat (1, 54 kg) as well as added more meat in cuts of higher commercial value, such as ham (1060 g, p < 0.05), loin (400 g, p > 0.05), belly (840 g, p < 0.05) and shoulder (1460 g, p < 0.05), which represents an economic advantage for the meat industry since reaches booths markets fresh and processed meats products (sausage and cooked). Regarding the sensory evaluation were found significant differences (p < 0.05) for all sensory attributes evaluated in favor ofimmunocastrated pigs when compared with physically castrated. The preference test applied to cooked sirloin steak from immunocastrated pigs indicated better preference (66%) compared with physically castrated (34%). The panelists intent to purchase was also in favor of the immunocastrated treatment and confirmed the results from the preference and acceptance tests. The majority (74.8%) of the consumers probably (20.2%) or certainly (54.6%) would buy meat from the immunocastrated pigs compared to 58.4% of the consumers who would probably (25.2%) or certainly (33.2%) would buy meat from physically castrated pigs. Loin total fat content found in the experiment was 14.67 and 12.67 g/100g for the physical and immunocastrated groups respectively. The immunocastrated group contained 11.2% less fat than the surgical castrates. Cooking yields and peak Warner-Bratzler shear force values from physically castrated and immunocastrated pigs were not statistically different (P > 0.05) while statistically significant differences (p < 0.05) in the brightness (L*), redness (a*) and yellowness (b*) parameters were observed between the two treatments. From the above considerations it can be said that immunocastration shows very good potential for pre-venting boar taint. Pain and stress associated with physical castration can thus be avoided. It was also demonstrated that immunocastrated pigs improved some meat quality aspects evaluated. Sensory, total fat content and color were the main factors affected by immunocastration while cooking loss and instrumental tenderness had no remarkable changes. The consumers classified meat from immunocastrated pigs significantly better than physically castrated pigs as far as acceptability, preference and purchase intention are concerned. Thus, immunocastration results in production of animals with high meat quality in the carcass and still capitalizes on the growth, feed efficiency and carcass leanness of boars up to the point of immunocastration.

MSCAGR / Department of Animal Science

Department of Animal Science / BSCAGR

PhD (AGR) (Animal Science) / Department of Animal Science / Horticultural by-products such as seed and nut oil residues have the potential to replace conventional protein and energy sources in diets for ruminants. The objective of the study was to evaluate the nutritive value of Macadamia oil cake and Baobab seed cake as nutrient supplements for feedlot animals. Several experiments were carried-out to evaluate the nutritive value of Macadamia oil cake and Baobab seed cake as feed for ruminants. The nutrient composition of the cakes were determined using both proximate and modern methods of analysis of feeds and a t-test was used to compare the means of Macadamia oil cake and Baobab seed cake. The in sacco technique was used to determine the rumen degradability parameters of dry matter, crude protein and Amino acids of the cakes. This experiment was conducted using a completely randomized design. A three step-in vitro technique was used to conduct a post ruminal digestibility trial and the study was arranged in a completely randomized design. An apparent digestibility trial was conducted using metabolism cages and fecal bags to avoid the mixing of urine and faeces and the experiment was carried out as a completely randomized design arranged in a 2 x 2 factorial. A growth trial was conducted using a completely randomized block design arranged in a 2x2 factorial with two protein supplements and two inclusion levels as factors and blocked by sex of the lambs. The two cakes had similar (P>0.05) dry matter, fat, hemicellulose and gross energy contents. Baobab seed cake had significantly (P<0.05) higher ash, crude protein, acid detergent lignin and nitrogen free extract than macadamia oil cake. Macadamia oil cake had significantly (P<0.05) higher crude fiber, acid detergent fiber, neutral detergent fiber and cellulose concentrations. Baobab seed cake had significantly (P<0.05) higher calcium, magnesium, potassium, phosphorus (macroelements), zinc, and copper than macadamia oil cake. Macadamia oil cake was significantly (P<0.05) higher in manganese and iron contents than Baobab seed cake. Sodium content was not significantly (P>0.05) different between the two cakes. Baobab seed cake had more (Tryptophan, Cysteine, Arginine, Aspartic acid, Glutamic acid, Valine, Phenylalanine, Isoleucine, Leucine) Amino acids which were significantly (P<0.05) higher in quantity than macadamia oil cake with the two cakes having similar (P>0.05) remaining Amino acids contents. Generally Macadamia oil cake had more (P<0.05) saturated and mono-unsaturated fatty acids than Baobab seed cake whereas Baobab seed cake had more (P<0.05) poly-unsaturated fatty acids. v The in sacco rumen degradability characteristics of baobab seed cake and macadamia oil cake were estimated for dry matter and crude protein of the cakes. Macadamia oil cake had significantly (P<0.01) higher a value for dry matter than boabab seed cake. Baoaba seed cake had significantly (P<0.01) higher a value for crude protein than macadamia oil cake. the b, c, and a+b values for dry matter of both Baobab seed cake and Macadamia oil cake were not significantly (P>0.05) different form each other. However, the potential degradability (a+b) value for crude protein of baobab seed cake was significantly (P<0.01) higher than that of macadamia oil cake. The b and c constants of the two cakes for crude protein were not significantly (P>0.05) different from each other. The ED (Effective degradability) values calculated at three outflow rates (0.02, 0.05, 0.08) were estimated for dry matter and crude protein of Baobab seed cake and macadamia oil cake. The ED of the two cakes calculated at 0.02 outflow rate did not significantly (P>0.05) differ from each other. However, baobab seed cake had significantly (P<0.05) higher ED value at outflow rate of 0.05 whereas macadamia oil cake had significantly (P<0.05) higher ED value calculated at outflow rate of 0.08. The ED values of baobab seed cake for crude protein calculated at the three outflow rate were significantly (P<0.01) higher than those of macadamia oil cake. The two cakes did not significantly (P>0.05) differ in dry matter ruminal degradability but baobab seed cake had significantly (P<0.05) higher ruminal crude protein disappearance from 16 to 72 hours of incubation than macadamia oil cake. The in situ Amino acid degradation was determined on 0, 12, 16, 24, and 48 hour of ruminal incubation of the cakes’ samples and generally they were significant (P<0.05) differences for both cakes according to different incubation periods. The 3-step in vitro digestibility trial revealed that baobab seed cake had significantly (P<0.05) higher dry matter, crude protein and Amino acids digestibility values than macadamia oil cake. Apparent digestibility study revealed that nutrient intake, faecal and urine outputs, and digestibility of nutrients were not significantly (P>0.05) different between baobab seed cake and macadamia oil cake. However, lambs on 10% macadamia cake having retained significantly (P<0.05) more nitrogen than the lambs on 15% macadamia oil cake, 10% and 15% baobab seed cakes diets. However, the inclusion of either baobab seed cake or macadamia oil cake at 10% or 15% in the diets of lambs did not significantly (P>0.05) affect the DOMR, microbial protein yield and purine derivates output. For the growth trial the lambs were offered four diets formulated to contain 10% MOC (control), 15% MOC, 10 BSC and 15% BSC. The inclusion of 15% MOC and 10% BSC in the diets of lambs did not significantly (P>0.05) affect their final body weight, total weight gain, average daily feed intake, average daily weight gain, warm and cold carcass masses between these two vi groups. The inclusion of 10% MOC and 15% BSC in the diets of lambs did not significantly affect average daily feed intake and animal performance between these two groups. However, lambs on 10% MOC and 15% BSC had significantly (P<0.05) higher average daily feed intake and animal performance compared to lambs on 15% MOC diet. The feed conversion efficiency and of the lambs in the four diets were not significantly (P>0.05) different. The dressing percentage, carcass length, neck weight, fat thickness, body weight thickness and rib eye area of the carcasses of lambs in this trial did not differ significantly (P>0.05) except for spleen and skin with lambs on 10% BSC diets having the least skin weight and lambs on 10% MOC diet having heaver spleens. Generally BSC had higher (P<0.05) nutrient content than MOC. BSC and MOC were highly degradable in the rumen whereas BSC was higly digestible post-ruminally compared to MOC. The diets of fattening lambs formulated to include 10% or 15% of BSC or MOC as protein supplements did not affect the apparent digestibility of the diets. Macadamia oil cake can be incomporated in the diet of finishing lambs as a protein supplement at 10% inclusion level without compromising the growth and carcass characteristics of the lambs. Baobab seed cake as a protein supplement can be included in the diet of finishing lambs at up to 15% inclusion level without deleteriously compromising on the growth and carcass characteristics of the animals. ______________________________________ / NRF

Thesis (M.Sc. (Animal Production)) -- University of Limpopo, 2023 / Two experiments were conducted to determine the effect of citric acid inclusion level in the diet on growth performance, carcass weight, tibia bone breaking strength and ash content of male Ross 308 broiler chickens aged one to 35 days. The first experiment determined the effect of citric acid inclusion level in the diet on growth performance traits of male Ross 308 broiler chickens aged one to 21 days. The experiment commenced with 200 male day-old Ross 308 broiler chickens with an initial average live weight of 40±1.6g per chick. The chicks were assigned to five treatment groups in a completely randomized design, each replicated five times, and each replicate having ten chicks. The citric acid inclusion levels were at 0, 12.5, 25 or 50g per kg DM of feed. The second experiment determined the effect of citric acid inclusion level in the diet on growth performance, carcass weight, tibia bone breaking strength and ash content traits of male Ross 308 broiler chickens aged 22 to 35 days. The experiment commenced with 180 male Ross 308 broiler chickens aged 22 days. The chickens were assigned to four treatment groups, each having three replicate pens of eight chickens per replicate in a completely randomized design. Data was analysed using the General Linear model (GLM) procedures of the Statistical Analysis of System, version 9.3.1 software program. Where there were significant differences (P<0.05) between the treatment means, Tukey Multiple Comparison Test was used for mean separation. Citric acid inclusion in the starter diets improved (P<0.05) live weight and growth rate of male Ross 308 broiler chickens aged one to 21 days. Citric acid inclusion in the starter diets did not affect (P>0.05) daily feed intake, body weight gain and feed conversion ratio of male Ross 308 broiler chickens aged one to 21 days. The inclusion of citric acid did affect (P<0.05) live weight, body weight gain, feed conversion ratio and growth rate of chickens aged 22 to 35 days. Citric acid inclusion levels used in the present study influenced (P<0.05) DM and CP digestibility, ME intake and N-retention of male broiler chickens aged 22 to 35 days. The results of the current study showed that citric acid inclusion in a diet improved (P<0.05) chicken bone morphology. Thus, positive relationships were observed between citric acid inclusion level and right tibia bone weight, diameter, calcium, phosphorous and Magnesium contents of chicken bones aged 35 days. There were positive relationships between citric acid inclusion level and breast weight of male Ross 308 broiler chickens aged 35 days. Further studies are recommended to ascertain these findings. / National Research Foundation (NRF)

La présente étude visait à déterminer les effets de l'âge de sevrage sur les performances de croissance, le développement du rumen et le microbiote chez les chevreaux alpins. Soixante-douze chevreaux ont été assignés au hasard par paires mâle et femelle à l'un des trois traitements. 1) sevrage précoce (EW), à l'âge de 6 semaines, 2) sevrage moyen (MW), à l'âge de 8 semaines (MW) et 3) sevrage tardif (LW), à 10 semaines d’âge (LW). Le lait de remplacement a été proposé ad libitum jusqu'à la semaine de sevrage, où le lait a été réduit de 12.5 % par jour pendant sept jours. Deux semaines après la naissance, du concentré, du foin et de l'eau ont été offerts à volonté jusqu'à l'âge de 12 semaines où les chevreaux ont été abattus. La consommation a été enregistrée quotidiennement et le poids corporel (PC) a été enregistré chaque semaine. Pour évaluer le développement du rumen, des échantillons de sang ont été prélevés pendant tout l'essai et analysés pour le β-hydroxybutyrate sanguin (BHB) et les acides gras non estérifiés (NEFA). Les mesures ruminales ont été prises à la semaine 12 avec les trente-six mâles seulement. Le contenu du rumen a été obtenu pour l'analyse de la composition bactérienne en utilisant la région V4 du gène de l'ARNr 16S et la qPCR a été utilisée pour quantifier les bactéries, les protozoaires et les champignons. Les papilles du rumen ont été analysées dans 4 régions du rumen : atrium du rumen (RA), sac ventral (VS), Cul-de-sac caudo-dorsal (DS) et Cul-de-sac caudo-ventral (VBS). Les chevreaux sevrés à 10 semaines, contre 8 semaines et 6 semaines avaient un gain quotidien moyen plus élevé pour la semaine post-sevrage (0.35 vs. 0.24 vs. 0.24 kg/j) et étaient plus lourds à la 12e semaine (27.44 vs. 25.45 vs. 24.07 kg, P< .05). Chez les animaux LW, le PC n'a pas été affecté pendant la période post-sevrage; probablement en raison d'un apport élevé en énergie métabolisable (EM) causé par la stratégie de sevrage contrairement à ce que nous observons chez les animaux EW et MW. Les taux sanguins de BHB ont augmenté au moment du sevrage pour tous les traitements, mais étaient plus élevés chez les chevreaux EW par rapport aux chevreaux MW (+ 21 %) et LW (+ 41 %) (P< .05). Les taux sanguins de NEFA chez les chevreaux EW ont augmenté au sevrage et étaient plus élevés que MW (+ 40 %) et LW (+ 101 %) chez les chevreaux (P< .05), suggérant une mobilisation plus prononcée du tissu adipeux chez les chevreaux sevrés précocement au sevrage. La population de microbiote en post-sevrage a montré que si le sevrage était retardé, l'abondance des bactéries totales semblait augmenter (P< .05) par rapport aux animaux EW, tandis que les protozoaires et les champignons diminuaient pour les LW. L'âge du sevrage semble induire des modifications du microbiote ruminal au cours du post-sevrage. Les mesures d'absorptiométrie à rayons X à double énergie (DEXA) des carcasses ont été utilisées comme indication de la récupération de la composition des graisses après le sevrage. Le tissu adipeux (%) dans LW était (9.4%) et EW était (7.2%) plus élevé par rapport à MW (P< .05). La surface totale de la papille était plus grande chez les chevreaux LW, par rapport aux chevreaux MW (+ 49 %) et EW (+ 22 %) (P< .05). Globalement, le sevrage des chevreaux à l'âge de 10 semaines a limité l'impact négatif d'un sevrage précoce sur la croissance et le développement du rumen de la race alpine. / The present study aimed to determine the effects of weaning age on growth performance, rumen development and microbiota composition in Alpine goat kids. Seventy-two kids were randomly assigned in pairs male and female to one of three treatments. 1) early weaning, at 6 wk of age (EW), 2) medium weaning, at 8 wk of age (MW) and 3) late weaning, at 10 wk of age (LW). Milk replacer (MR) was offered ad libitum until the step-down wk, when milk was reduced by 12.5% per day for seven days. Two wk after birth, starter ration, hay, and water were offered ad libitum until 12 wk of age where kids were slaughtered. Feed intake was recorded daily, and body weight (BW) was recorded weekly. To evaluate rumen development, blood samples were taken during the whole trial and analyzed for blood β-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA). Ruminal measurements such as papillae, VFAs and microbiota were taken at wk 12 with only thirty-six males. Rumen contents were obtained for bacteria composition analysis using the V4 region of the 16S rRNA gene and qPCR was used to quantify bacteria, protozoa and fungi. Rumen papillae were obtained for histological analysis in 4 rumen areas: rumen atrium (RA), ventral sac (VS), caudodorsal blind sac (DS), and caudoventral blind sac (VBS). Kids weaned at 10 wk, compared with 8 wk and 6wk had higher average daily gain for the wk postweaning (0.35 vs. 0.24 vs. 0.24 kg / d) and were heavier at wk 12 (27.44 vs. 25.45 vs. 24.07 kg, P< .05). In LW animals, BW was not affected during post weaning period; possibly due to high metabolizable energy (ME) intake caused by the weaning strategy contrary to what was observed in EW and MW animals. Blood levels of BHB increased at weaning time for all treatments but were higher in EW compared to MW (+21%) and LW (+41%) kids (P< .05). Blood levels of NEFAs in EW kids spiked at weaning and were higher than MW (+ 40%) and LW (+101%) in kids (P< .05), suggesting a more pronounced adipose tissue mobilization in early weaned kids at weaning. Microbiota population in postweaning showed that while weaning was delayed, abundance of total bacteria seemed to increase (P< .05) compared with EW animals, whereas protozoa and fungi decreased for LW. Weaning age influences the ruminal microbiota during postweaning. Dual-energy X-ray absorptiometry (DEXA) measurements of carcasses were used as an indication of fat composition recovery in post-weaning. Fat tissue (%) in LW was (9.4%), and EW was (7.2%) higher compared to MW (P< .05). The total papilla surface area was greater in LW, compared to MW (+49%) and EW (+22%) kids (P< .05). Overall weaning kids at 10 wk of age limited the negative impact of earlier weaning on growth and rumen development in the Alpine breed.

An experiment was conducted using forty-one Bonsmara steers (age ± 7 months) to determine the effect of zilpaterol hydrochloride (ZH) on the growth performance and carcass characteristics. The trial was structured using a completely randomized design with two treatments, control and ZH group. The steers were fed ZH for 28 consecutive days at the end of the finishing period and ZH was withdrawn from the diet 2 days prior to slaughter of the animals. The steers were placed in individual pens and weighed fortnightly throughout the 4 months trial. Zilpaterol hydrochloride (ZH) was included in the diet at a rate of 8.3 mg/kg of DM. Feeding of ZH increased (P< 0.05) body weight (BW) gain and ADG (1.102 vs. 1.444) and tended to increase (P = 0.067) feed efficiency (F:G) during the last month of the finishing period. There were no significant differences (P> 0.05) in daily dry matter intakes (DMI). For the control group, high treatment weight gains were significantly associated with high initial weight (r = 0.424, P = 0.049) and also high pre-treatment body weight (r = 0.678, P= 0.001). Treatment weight gain increased as the initial and pre-treatment weight gain increased in the control group. For the steers that were fed ZH, there was no significant correlation between the treatment body weight gain with initial weight (r = 0.097, P = 0.694) and also pre- treatment live weight (r = 0.393, P = 0.096). Supplementation of ZH significantly increased (P < 0.0001) the dressing percentage (56.4% vs. 58.4%) and had no significant (P>0.05) effect on the carcass weight. The outcome of the study suggest that supplementation of ZH in the diet during the last month of the finishing period enhances growth performance and shows the repartitioning capacity of the feed additive as a beta- agonist. / Agriculture and  Animal Health / M. Sc. (Agriculture (Animal Science)

One of the major problems facing aquaculture in Ghana is the non-availability of quality and affordable fish feeds. The present study investigated the nutritional suitability and cost-effectiveness of some Ghanaian oilseed by-products, soybean meal (Glycine spp), cottonseed meal (Gossypium spp), groundnut cake (Arachis hypogaea L.) and groundnut husk, as alternative protein sources to fishmeal (FM) in the diet of Nile tilapia (Oreochromis niloticus L.). The oilseed meals were used individually, as mixtures, as mixtures enriched with methionine and mixtures detoxified by heat processing (autoclaving) and/or addition of supplements (viz. phytase and ferrous sulphate) intended to reduce levels of the most important antinutritional factors (ANFs). Diets, containing the oilseed meals at inclusion levels from 25% to 75% dietary protein, were formulated to be isonitrogenous (320 g.kg-1), isolipidic (100 g.kg-1) and isoenergetic (18 KJ.g-1) and fed to juvenile Nile tilapia at 4-10% of their body weight for a period of eight weeks. Proximate analysis showed that soybean meal (SBM), cottonseed meal (CSM), groundnut cake (GNC) and groundnut husk (GNH) had 500.3, 441.4, 430.5 and 205.6 g.kg-1 crude protein, 38.2, 89.5, 12.8 and 89.2 g.kg-1 crude fibre and 20.19, 19.61, 23.17 and 22.18 kJ.g-1 gross energy respectively. Generally the oilseed meals had good essential amino acid (EAA) profiles with the exception of GNH. The EAA profile of SBM compared very well with FM but methionine and threonine were low (0.73 and 1.50 % of protein respectively) and the same was true for CSM and GNC with even lower levels. Analyzed ANFs in SBM, CSM, GNC and GNH were 17.54, 31.64, 14.86 and 3.99 g.kg-1 phytic acid, 14.09, 1.24 and 2.34 g.kg-1 trypsin inhibitors and 5.80, 6.50, 8.01 and 10.08 g.kg-1 saponin respectively and in CSM 5.6 g.kg-1 gossypol. Nutrient digestibility of these oilseed proteins suggested that Nile tilapia may be able to utilize SBM, CSM and GNC efficiently as dietary protein sources due to high apparent protein digestibility of 94.50%, 84.93% and 90.01% respectively. However, GNH may not be suitable because of very low apparent protein digestibility (27.67%). These protein sources when used individually were shown to cause depressed growth and feed efficiency when substituting more than 50% of the FM protein in diets. This may be attributed to high levels of ANFs, high fibre content and poor EAA profile. However, the use of mixtures of these meals was found to be marginally more effective than that of single sources. This may have been as a result of lower levels of ANFs and improvement in essential amino acid profile due to mixing. Supplementing the mixtures with methionine led to improvement in feed utilization but without significantly improving the nutritive value compared with FM. Heat processing was effective in reducing heat labile trypsin inhibitors in SBM, CSM and GNC by almost 80%, but not phytic acid and saponins, which remained virtually unaffected. Use of meals detoxified by heat processing with/without supplements at 50% inclusion improved growth and feed utilization compared to the unprocessed meals and performance was generally not significantly different from FM. Cost effectiveness analysis revealed that diets containing single feedstuffs or mixtures, particularly those containing equal proportions of oilseed meals and higher proportion of CSM replacing between 50% - 75% FM protein, were more profitable than FM diet. Similarly, the use of heat processed meals at 50% replacement of FM protein yielded greater profit than all other diets including the FM diet. However, essential amino acid supplementation of the meals was less profitable compared to the control. Generally, fish fed diets with oilseed meals would take longer to attain harvest size compared with FM and this could lead to an increase in production costs or a decrease in the number of production cycles which could be achieved within a year. It can be concluded that there is nutritional and economic justification for using SBM, CSM and GNC as partial replacement for FM in diets of Nile tilapia. Based on growth performance, nutrient utilization and economic benefits the diet with heat processed oilseed meal mixtures (containing equal proportions of 16.67% each) at 50% inclusion has the best prospects for replacing FM protein in diets of O. niloticus.

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