Effect of Housing Design and Location on Production and Economic Performance of Broiler Chickens during Summer in Botswana

Botswana experiences long, hot summer periods which negatively affect broiler productivity and results in economic losses. To determine these negative effects, two parallel broiler production studies were conducted in the North eastern (NE) and South eastern (SE) regions. In each region, three large scale commercial broiler farms were randomly selected based on similarities in bird management and housing systems. In each farm, one house type (Gable, Hoop and See-saw) was selected for long term flock monitoring (1 to 35 days) over three production cycles. Results showed that the production performance of the broilers in the SE region was superior to that in the NE region, with temperatures on being average higher in the NE than in the SE. The European Production Efficiency Factor (EPEF) was significantly higher (p0.05) between the regions at 9.0% and 7.4% for the NE and SE, respectively. In the NE, the Gable structure had the highest profitability and economic efficiency and was thus superior in comparison to the other house structures.(AU)

Requirement of digestible methionine + cystine for growing Japanese quail and its subsequent effects on laying phase

The objective of this study was to estimate the nutritional requirement of digestible methionine + cystine for Japanese quail during the growth phase and its residual effect on the laying phase. One experiment was conducted, including three phases: starter, from 1 to 14 days of age; grower, from 15 to 42 days of age; and laying, from 43 to 168 days of age. The experimental design was entirely randomized with five treatments (0.52, 0.64, 0.76, 0.88, and 1.00% of digestible methionine + cystine) and five replicates. In starter phase, 48 quail/experimental unit (box) were used; in grower phase, 31 quail/experimental unit (box) were used, which were reared until 14 days old, receiving conventional feed and, in laying phase, 12 quail/experimental unit were selected from grower phase to evaluate the residual effect. To evaluate animal performance, feed intake (g/bird), body weight (g), weight gain (g), feed conversion (g/g), and viability (%) were analyzed. At 14 and 42 days of age, the relative weight (%) of liver, spleen, and cloacal pouch organs, the birds' warping (%) and body chemical composition (%) were evaluated. During laying, performance and egg quality were evaluated. In the starter and grower stages, quadratic effects were observed for all performance variables. Laying performance results confirmed the estimates obtained in the grower phase; however, there was no effect on egg quality. Considering the best feed conversion, the nutritional recommendation of digestible methionine + cystine for Japanese quail in the starter phase is 0.85% and in the grower phase, it is 0.77%, corresponding to daily intake of 50.43 and 158.5 mg of digestible methionine + cystine/day, respectively.

Performance and meat quality of Label Rouge chickens at different slaughter ages / Parâmetros de produção e qualidade da carne de frangos Label Rouge em diferentes idades de abate

ABSTRACT: This study evaluated the performance parameters, carcass characteristics, and meat quality of Label Rouge chickens raised under an alternative system as a function of age at slaughter. The design was completely randomized with a 5×2 factorial arrangement, with slaughtering at five ages (70, 90, 120, 150, and 180 days) and two sexes. A total of 240 birds (Pescoço Pelado strain) were used, including 120 females and 120 males. Performance, carcass, physicochemical, proximate composition, and muscle fiber traits were evaluated. Rearing time and sex had significant effects on performance-related traits, with better results for males. The interaction between slaughter age and sex had a significant effect on the carcass and physicochemical parameters, which cause different responses in males and females with increasing slaughter age. For the proximate composition and muscle fiber analysis, the interaction between the parameters studied only had a significant effect on ether extract in the breast. The increase in age resulted in chickens with higher live and carcass weight at slaughter but lower performance indices. Females had lower carcass yield and greater deposition of abdominal fat. Females had lower tenderness in the drumstick and males in the breast with increasing slaughter age, and both cuts had more intense color and redness and reduced lightness starting at the slaughter age of 90 days.

RESUMO: O objetivo deste estudo foi avaliar os parâmetros de desempenho e as características de carcaça e qualidade da carne de frangos Label Rouge criados em sistema alternativo em função do aumento da idade de abate. O delineamento foi inteiramente casualizado (DIC) disposto em esquema fatorial (2x5), sendo dois sexos (macho e fêmea) e cinco idades de abate (70, 90, 120, 150 e 180 dias). Foram utilizadas 240 aves (Pescoço Pelado), sendo 120 fêmeas e 120 machos, sendo avaliados os parâmetros de desempenho, carcaça, físico-químicos, composição centesimal e fibra muscular. Com o aumento no tempo de produção houve efeitos dos períodos de produção e sexo em relação a variáveis de desempenho, com melhores resultados para os machos. Para os parâmetros de carcaça e físico-químicos, houve interação entre sexo e idade de abate, revelando comportamento diferenciado para machos e fêmeas com aumento da idade de abate. Para a composição centesimal e análise das fibras musculares, somente para extrato etéreo no peito foi verificado interação entre os fatores estudados. O aumento da idade proporcionou a obtenção de frangos com maiores pesos vivos e de carcaça ao abate com consequente redução dos índices de desempenho, além de menor rendimento de carcaça e maior deposição de gordura abdominal nas fêmeas. As fêmeas apresentam menor maciez na coxa e os machos no peito com aumento da idade de abate e, em ambos os cortes, ocorreu maior intensificação da cor, índice de vermelho e redução do brilho a partir de 90 dias ou em maiores idades de abate.

Performance and meat quality of Label Rouge chickens at different slaughter ages / Parâmetros de produção e qualidade da carne de frangos Label Rouge em diferentes idades de abate

This study evaluated the performance parameters, carcass characteristics, and meat quality of Label Rouge chickens raised under an alternative system as a function of age at slaughter. The design was completely randomized with a 5×2 factorial arrangement, with slaughtering at five ages (70, 90, 120, 150, and 180 days) and two sexes. A total of 240 birds (Pescoço Pelado strain) were used, including 120 females and 120 males. Performance, carcass, physicochemical, proximate composition, and muscle fiber traits were evaluated. Rearing time and sex had significant effects on performance-related traits, with better results for males. The interaction between slaughter age and sex had a significant effect on the carcass and physicochemical parameters, which cause different responses in males and females with increasing slaughter age. For the proximate composition and muscle fiber analysis, the interaction between the parameters studied only had a significant effect on ether extract in the breast. The increase in age resulted in chickens with higher live and carcass weight at slaughter but lower performance indices. Females had lower carcass yield and greater deposition of abdominal fat. Females had lower tenderness in the drumstick and males in the breast with increasing slaughter age, and both cuts had more intense color and redness and reduced lightness starting at the slaughter age of 90 days.

O objetivo deste estudo foi avaliar os parâmetros de desempenho e as características de carcaça e qualidade da carne de frangos Label Rouge criados em sistema alternativo em função do aumento da idade de abate. O delineamento foi inteiramente casualizado (DIC) disposto em esquema fatorial (2x5), sendo dois sexos (macho e fêmea) e cinco idades de abate (70, 90, 120, 150 e 180 dias). Foram utilizadas 240 aves (Pescoço Pelado), sendo 120 fêmeas e 120 machos, sendo avaliados os parâmetros de desempenho, carcaça, físico-químicos, composição centesimal e fibra muscular. Com o aumento no tempo de produção houve efeitos dos períodos de produção e sexo em relação a variáveis de desempenho, com melhores resultados para os machos. Para os parâmetros de carcaça e físico-químicos, houve interação entre sexo e idade de abate, revelando comportamento diferenciado para machos e fêmeas com aumento da idade de abate. Para a composição centesimal e análise das fibras musculares, somente para extrato etéreo no peito foi verificado interação entre os fatores estudados. O aumento da idade proporcionou a obtenção de frangos com maiores pesos vivos e de carcaça ao abate com consequente redução dos índices de desempenho, além de menor rendimento de carcaça e maior deposição de gordura abdominal nas fêmeas. As fêmeas apresentam menor maciez na coxa e os machos no peito com aumento da idade de abate e, em ambos os cortes, ocorreu maior intensificação da cor, índice de vermelho e redução do brilho a partir de 90 dias ou em maiores idades de abate.

Limiting amino acids supplementation in low crude protein diets and their impacts on growth performance and carcass composition in Labeo rohita (rohu) adult fish / Limitação da suplementação de aminoácidos em dietas com baixo teor de proteína bruta e seus impactos no desempenho de crescimento e composição da carcaça em peixes adultos Labeo rohita (rohu)

Ninety days study was conducted in hapas installed in earthen ponds. Fish of an average initial weight (220g) were evenly distributed in triplicate groups within fifteen hapas. Five experimental diets labeled as T1 (25% CP and NRC recommended amino acid level) as control diet, T2 (with 2% low protein and 5% amino acid supplementation), T3 (with 2% low protein and 10% amino acid supplementation), T4 (with 4% low protein and 10% amino acid supplementation) and T5 (with 4% low protein and 20% amino acid supplementation) were prepared. Fish were fed with @3% of their body weight twice a day at 10.00 & 16:00 hour. Significantly higher percent weight gain (420.18 ± 66.84a) and specific growth rate (13499.33±1273.54a) along with improved feed conversion ratio (1.29 ± 0.09b) and hundred percent survivals were recorded during the trial. Furthermore proximate analysis of meat showed significant improvement in the crude protein level (81.77 ± 0.19a) served with diet containing 20% limiting amino acids mixture. Therefore, limiting amino acids can be a source of cost effective feed and use safely in L. rohita diet.

O estudo de 90 dias foi realizado em hapas instalados em tanques de terra. Peixes com peso inicial médio (220 g) foram distribuídos uniformemente em grupos triplicados em 15 hapas. Cinco dietas experimentais rotuladas como T1 (25% de CP e NRC recomendado nível de aminoácidos) como dieta controle, T2 (com 2% de proteína baixa e 5% de suplementação de aminoácidos), T3 (com 2% de proteína baixa e 10% de suplementação de aminoácidos), T4 (com 4% de baixa proteína e 10% de suplementação de aminoácidos) e T5 (com 4% de baixa proteína e 20% de suplementação de aminoácidos) foram preparadas. Os peixes foram alimentados com 3% do seu peso corporal duas vezes por dia às 10h00 e 16h00. Ganho de peso significativamente maior (420,18 ± 66,84a) e taxa de crescimento específico (13499,33 ± 1273,54a) juntamente com taxa de conversão alimentar melhorada (1, 29 ± 0,09b) e sobrevivência de cem por cento foram registrados durante o ensaio. Além disso, a análise aproximada da carne mostrou melhora significativa no nível de proteína bruta (81,77 ± 0,19a) servida com dieta contendo 20% de mistura de aminoácidos limitantes. Portanto, a limitação de aminoácidos pode ser uma fonte de alimentação econômica e usada com segurança na dieta de L. rohita.

Limiting amino acids supplementation in low crude protein diets and their impacts on growth performance and carcass composition in Labeo rohita (rohu) adult fish

Abstract Ninety days study was conducted in hapas installed in earthen ponds. Fish of an average initial weight (220g) were evenly distributed in triplicate groups within fifteen hapas. Five experimental diets labeled as T1 (25% CP and NRC recommended amino acid level) as control diet, T2 (with 2% low protein and 5% amino acid supplementation), T3 (with 2% low protein and 10% amino acid supplementation), T4 (with 4% low protein and 10% amino acid supplementation) and T5 (with 4% low protein and 20% amino acid supplementation) were prepared. Fish were fed with @3% of their body weight twice a day at 10.00 & 16:00 hour. Significantly higher percent weight gain (420.18 ± 66.84a) and specific growth rate (13499.33±1273.54a) along with improved feed conversion ratio (1.29 ± 0.09b) and hundred percent survivals were recorded during the trial. Furthermore proximate analysis of meat showed significant improvement in the crude protein level (81.77 ± 0.19a) served with diet containing 20% limiting amino acids mixture. Therefore, limiting amino acids can be a source of cost effective feed and use safely in L. rohita diet.

Resumo O estudo de 90 dias foi realizado em hapas instalados em tanques de terra. Peixes com peso inicial médio (220 g) foram distribuídos uniformemente em grupos triplicados em 15 hapas. Cinco dietas experimentais rotuladas como T1 (25% de CP e NRC recomendado nível de aminoácidos) como dieta controle, T2 (com 2% de proteína baixa e 5% de suplementação de aminoácidos), T3 (com 2% de proteína baixa e 10% de suplementação de aminoácidos), T4 (com 4% de baixa proteína e 10% de suplementação de aminoácidos) e T5 (com 4% de baixa proteína e 20% de suplementação de aminoácidos) foram preparadas. Os peixes foram alimentados com 3% do seu peso corporal duas vezes por dia às 10h00 e 16h00. Ganho de peso significativamente maior (420,18 ± 66,84a) e taxa de crescimento específico (13499,33 ± 1273,54a) juntamente com taxa de conversão alimentar melhorada (1, 29 ± 0,09b) e sobrevivência de cem por cento foram registrados durante o ensaio. Além disso, a análise aproximada da carne mostrou melhora significativa no nível de proteína bruta (81,77 ± 0,19a) servida com dieta contendo 20% de mistura de aminoácidos limitantes. Portanto, a limitação de aminoácidos pode ser uma fonte de alimentação econômica e usada com segurança na dieta de L. rohita.

Limiting amino acids supplementation in low crude protein diets and their impacts on growth performance and carcass composition in Labeo rohita (rohu) adult fish / Limitação da suplementação de aminoácidos em dietas com baixo teor de proteína bruta e seus impactos no desempenho de crescimento e composição da carcaça em peixes adultos Labeo rohita (rohu)

Abstract Ninety days study was conducted in hapas installed in earthen ponds. Fish of an average initial weight (220g) were evenly distributed in triplicate groups within fifteen hapas. Five experimental diets labeled as T1 (25% CP and NRC recommended amino acid level) as control diet, T2 (with 2% low protein and 5% amino acid supplementation), T3 (with 2% low protein and 10% amino acid supplementation), T4 (with 4% low protein and 10% amino acid supplementation) and T5 (with 4% low protein and 20% amino acid supplementation) were prepared. Fish were fed with @3% of their body weight twice a day at 10.00 & 16:00 hour. Significantly higher percent weight gain (420.18 ± 66.84a) and specific growth rate (13499.33±1273.54a) along with improved feed conversion ratio (1.29 ± 0.09b) and hundred percent survivals were recorded during the trial. Furthermore proximate analysis of meat showed significant improvement in the crude protein level (81.77 ± 0.19a) served with diet containing 20% limiting amino acids mixture. Therefore, limiting amino acids can be a source of cost effective feed and use safely in L. rohita diet.

Resumo O estudo de 90 dias foi realizado em hapas instalados em tanques de terra. Peixes com peso inicial médio (220 g) foram distribuídos uniformemente em grupos triplicados em 15 hapas. Cinco dietas experimentais rotuladas como T1 (25% de CP e NRC recomendado nível de aminoácidos) como dieta controle, T2 (com 2% de proteína baixa e 5% de suplementação de aminoácidos), T3 (com 2% de proteína baixa e 10% de suplementação de aminoácidos), T4 (com 4% de baixa proteína e 10% de suplementação de aminoácidos) e T5 (com 4% de baixa proteína e 20% de suplementação de aminoácidos) foram preparadas. Os peixes foram alimentados com 3% do seu peso corporal duas vezes por dia às 10h00 e 16h00. Ganho de peso significativamente maior (420,18 ± 66,84a) e taxa de crescimento específico (13499,33 ± 1273,54a) juntamente com taxa de conversão alimentar melhorada (1, 29 ± 0,09b) e sobrevivência de cem por cento foram registrados durante o ensaio. Além disso, a análise aproximada da carne mostrou melhora significativa no nível de proteína bruta (81,77 ± 0,19a) servida com dieta contendo 20% de mistura de aminoácidos limitantes. Portanto, a limitação de aminoácidos pode ser uma fonte de alimentação econômica e usada com segurança na dieta de L. rohita.

Supplementation of yeast culture combined with an enzyme complex in the diet for confined steers / Suplementação de cultura de leveduras em associação com complexo enzimático na dieta de novilhos confinados

The objective was to evaluate the productive performance, apparent digestibility of the diet and ingestive behavior of beef cattle finished in feedlot under the effect of the inclusion of yeast culture or enzyme complex. The treatments were: diet without additives (control); diet with enzyme complex (7 g animal day-1); diet with yeast culture (7g animal day-1) and diet with the association of enzymatic complex (7 g animal day-1) and yeast culture (7g animal day-1). The experimental design was completely randomized, with five replications. Forty ½ Angus ½ Nellore steers, with an average initial body weight of 362 kg ± 6 kg, were used. Regardless of the evaluation period, non-supplementation caused the animals to gain less weight (0 to 21 days: 1.267 kg day-1; 0 to 42 days: 1.377 kg day-1; 0 to 63 days: 1.368 kg day-1) compared to supplemented animals, feed conversion for non-supplemented animals was also worse. Starch apparent digestibility showed higher averages when steers were supplemented with yeast culture alone and yeast culture combined with enzyme complex (97.30% and 97.07%, respectively). Supplementation using a combination of yeast culture with enzyme complex did not cause additional effects on weight gain, but resulted in the lowest averages for feed conversion.(AU)

Objetivou-se avaliar o desempenho produtivo, digestibilidade aparente da dieta e comportamento ingestivo de bovinos de corte terminados em confinamento sob efeito da inclusão de cultura de leveduras ou de complexo enzimático. Os tratamentos foram assim constituídos: dieta sem aditivos (controle); dieta com complexo enzimático (7 g animal dia-1); dieta com cultura de levedura (7g animal dia-1) e dieta com a associação de complexo enzimático (7 g animal dia-1) e cultura de levedura (7g animal dia-1). O delineamento experimental foi o inteiramente casualizado, com cinco repetições. Utilizou-se 40 novilhos inteiros, ½ sangue Angus ½ sangue Nelore, com peso vivo médio inicial de 362 kg ± 6kg. Independente do período de avaliação, a não suplementação fez com que os animais ganhassem menos peso (0 a 21 dias: 1,267 kg dia-1; 0 a 42 dias: 1,377 kg dia-1; 0 a 63 dias: 1,368 kg dia-1) em relação aos animais suplementados, a conversão alimentar para os animais não suplementados também foi pior. A digestibilidade aparente do amido apresentou maiores médias quando os novilhos foram suplementados com cultura de levedura isolada e com cultura de levedura associada com complexo enzimático (97,30% e 97,07% respectivamente). A suplementação na forma de associação da cultura de leveduras ao complexo enzimático não apresentou efeitos adicionais sobre o ganho de peso, mas possui as menores médias para conversão alimentar.(AU)

Limiting amino acids supplementation in low crude protein diets and their impacts on growth performance and carcass composition in Labeo rohita (rohu) adult fish / Limitação da suplementação de aminoácidos em dietas com baixo teor de proteína bruta e seus impactos no desempenho de crescimento e composição da carcaça em peixes adultos Labeo rohita (rohu)

Ninety days study was conducted in hapas installed in earthen ponds. Fish of an average initial weight (220g) were evenly distributed in triplicate groups within fifteen hapas. Five experimental diets labeled as T1 (25% CP and NRC recommended amino acid level) as control diet, T2 (with 2% low protein and 5% amino acid supplementation), T3 (with 2% low protein and 10% amino acid supplementation), T4 (with 4% low protein and 10% amino acid supplementation) and T5 (with 4% low protein and 20% amino acid supplementation) were prepared. Fish were fed with @3% of their body weight twice a day at 10.00 & 16:00 hour. Significantly higher percent weight gain (420.18 ± 66.84a) and specific growth rate (13499.33±1273.54a) along with improved feed conversion ratio (1.29 ± 0.09b) and hundred percent survivals were recorded during the trial. Furthermore proximate analysis of meat showed significant improvement in the crude protein level (81.77 ± 0.19a) served with diet containing 20% limiting amino acids mixture. Therefore, limiting amino acids can be a source of cost effective feed and use safely in L. rohita diet.(AU)

O estudo de 90 dias foi realizado em hapas instalados em tanques de terra. Peixes com peso inicial médio (220 g) foram distribuídos uniformemente em grupos triplicados em 15 hapas. Cinco dietas experimentais rotuladas como T1 (25% de CP e NRC recomendado nível de aminoácidos) como dieta controle, T2 (com 2% de proteína baixa e 5% de suplementação de aminoácidos), T3 (com 2% de proteína baixa e 10% de suplementação de aminoácidos), T4 (com 4% de baixa proteína e 10% de suplementação de aminoácidos) e T5 (com 4% de baixa proteína e 20% de suplementação de aminoácidos) foram preparadas. Os peixes foram alimentados com 3% do seu peso corporal duas vezes por dia às 10h00 e 16h00. Ganho de peso significativamente maior (420,18 ± 66,84a) e taxa de crescimento específico (13499,33 ± 1273,54a) juntamente com taxa de conversão alimentar melhorada (1, 29 ± 0,09b) e sobrevivência de cem por cento foram registrados durante o ensaio. Além disso, a análise aproximada da carne mostrou melhora significativa no nível de proteína bruta (81,77 ± 0,19a) servida com dieta contendo 20% de mistura de aminoácidos limitantes. Portanto, a limitação de aminoácidos pode ser uma fonte de alimentação econômica e usada com segurança na dieta de L. rohita.(AU)

Grape pomace silage on growth performance, carcass, and meat quality attributes of lambs

Grape pomace is a by-product that can be ensiled and added to animal feed for a sustainable animal production. This study evaluated the effects of grape pomace silage (GPS) on the intake, performance, and carcass and meat quality of feedlot lambs. Twenty-four male lambs (21.5 ± 3.0 kg initial body weight) were distributed into pairs to four diets levels 0, 10, 20, and 30 % of GPS. The addition of grape pomace silage influenced only ether extract (EE) intake linearly without hindering consumption. The diet did not affect performance and meat quality attributes and carcass parameters, with average daily gain (ADG) of 0.235 kg d-¹, feed conversion 4.299, carcass conformation 2.7, compactness index 0.25 kg cm-¹, fat thickness 1.51 mm, loin eye area 13.9 cm², pH 5.79, natural matter moisture 74.05 g 100 g-¹, and crude protein (CP) 19.94 g per 100 g-¹ of dry matter (DM). Grape pomace as could be used as silage in lamb diets with up to 30 % GPS, as the chemical composition of this by-product and the results indicate that GPS did not compromise performance, carcass traits, and meat quality.

Estimation of productive losses caused by withdrawal of antibiotic growth promoter from pig diets Meta-analysis

ABSTRACT: This study was designed to simulate productive and economic losses due to the withdrawal of antibiotic growth promoters (AGP) from pig diets. Articles that compared diets with AGP (AGP+) or without AGP (AGP) for pigs were collected from electronic databases and the performance results were entered in a database. A meta-analysis was performed following the sequence: graphical analysis, correlation, and variance-covariance. The performance results observed in the meta-analysis, feed cost, and AGP costs were used to build equations to estimate the economic effect of withdrawing AGP. The database comprised 81 scientific articles containing 103 experiments totalizing 42,923 pigs. Avilamycin (24.7 %) was the most frequent AGP in the database, followed by Colistin (15.4 %), Tiamulin (11.7 %), Tylosin (8.0 %), Lincomycin (9.4 %), and Bacitracin (5.4 %). Weight gain (p 0.05) increased in AGP+ diets during post-weaning (6.5 %). However, there was no effect of AGP on weight gain of growing-finishing pigs. There was better (p 0.05) feed conversion in pigs fed AGP+ diets in all rearing phases. Weight gain and feed conversion improved (p 0.05) with the addition of Avilamycin, Bacitracin, and Tylosin. AGP withdrawal in the post-weaning phase increased feed costs by US$ 0.86 per animal and in growing-finishing phase the increase was US$ 3.11. Thus, pigs fed AGP+ diets have a better performance than pigs fed AGP- diets and the withdrawal of AGP increases feed costs.

Estimation of productive losses caused by withdrawal of antibiotic growth promoter from pig diets – Meta-analysis

This study was designed to simulate productive and economic losses due to the withdrawal of antibiotic growth promoters (AGP) from pig diets. Articles that compared diets with AGP (AGP+) or without AGP (AGP–) for pigs were collected from electronic databases and the performance results were entered in a database. A meta-analysis was performed following the sequence: graphical analysis, correlation, and variance-covariance. The performance results observed in the meta-analysis, feed cost, and AGP costs were used to build equations to estimate the economic effect of withdrawing AGP. The database comprised 81 scientific articles containing 103 experiments totalizing 42,923 pigs. Avilamycin (24.7 %) was the most frequent AGP in the database, followed by Colistin (15.4 %), Tiamulin (11.7 %), Tylosin (8.0 %), Lincomycin (9.4 %), and Bacitracin (5.4 %). Weight gain (p < 0.05) increased in AGP+ diets during post-weaning (6.5 %). However, there was no effect of AGP on weight gain of growing-finishing pigs. There was better (p < 0.05) feed conversion in pigs fed AGP+ diets in all rearing phases. Weight gain and feed conversion improved (p < 0.05) with the addition of Avilamycin, Bacitracin, and Tylosin. AGP withdrawal in the post-weaning phase increased feed costs by US$ 0.86 per animal and in growing-finishing phase the increase was US$ 3.11. Thus, pigs fed AGP+ diets have a better performance than pigs fed AGP- diets and the withdrawal of AGP increases feed costs.

Estimation of productive losses caused by withdrawal of antibiotic growth promoter from pig diets Meta-analysis

This study was designed to simulate productive and economic losses due to the withdrawal of antibiotic growth promoters (AGP) from pig diets. Articles that compared diets with AGP (AGP+) or without AGP (AGP–) for pigs were collected from electronic databases and the performance results were entered in a database. A meta-analysis was performed following the sequence: graphical analysis, correlation, and variance-covariance. The performance results observed in the meta-analysis, feed cost, and AGP costs were used to build equations to estimate the economic effect of withdrawing AGP. The database comprised 81 scientific articles containing 103 experiments totalizing 42,923 pigs. Avilamycin (24.7 %) was the most frequent AGP in the database, followed by Colistin (15.4 %), Tiamulin (11.7 %), Tylosin (8.0 %), Lincomycin (9.4 %), and Bacitracin (5.4 %). Weight gain (p < 0.05) increased in AGP+ diets during post-weaning (6.5 %). However, there was no effect of AGP on weight gain of growing-finishing pigs. There was better (p < 0.05) feed conversion in pigs fed AGP+ diets in all rearing phases. Weight gain and feed conversion improved (p < 0.05) with the addition of Avilamycin, Bacitracin, and Tylosin. AGP withdrawal in the post-weaning phase increased feed costs by US$ 0.86 per animal and in growing-finishing phase the increase was US$ 3.11. Thus, pigs fed AGP+ diets have a better performance than pigs fed AGP- diets and the withdrawal of AGP increases feed costs.(AU)

Effects of Male Selection for Body Weight on Performance of Offsprings in Broiler Pure-Lines

This study aimed to determine the effects of the variation in body weight (BW) in pure lines even after selection on the BW and feed conversion ratio (FCR) of offsprings in broiler pure-lines. The males of the dam (A1) and sire (B1) line were grouped according to their BW after selection at the 6th and 12 th weeks of age. In the sire lines, the heaviest males at six weeks of age were selected (300), and the selected males were divided into three groups in terms of BW as average (B11: 100 males), high (B12: 100 males), and the highest (B13: 100 males). In the dam lines, the selected males were divided into three groups as an average (A11: 100 males), low (A12: 100 males), and high BW (A13: 100 males). In the dam line, offsprings of males with average and high BW had the highest BW at 42 days of age compared to the low BW group (p<0.05). However, there was no statistically significant difference in BW between the BW groups in the offsprings of the sire line. Offsprings of dam line males with average and higher than average BW had better FCR values. However, there was no significant change in FCR between the offsprings of the sire line BW groups. As a result, it is thought that by preserving the variation at a certain level in future generations, a significant improvement can be achieved in the BW and FCR by selecting heavier males.(AU)

Effects of Male Selection for Body Weight on Performance of Offsprings in Broiler Pure-Lines

This study aimed to determine the effects of the variation in body weight (BW) in pure lines even after selection on the BW and feed conversion ratio (FCR) of offsprings in broiler pure-lines. The males of the dam (A1) and sire (B1) line were grouped according to their BW after selection at the 6th and 12 th weeks of age. In the sire lines, the heaviest males at six weeks of age were selected (300), and the selected males were divided into three groups in terms of BW as average (B11: 100 males), high (B12: 100 males), and the highest (B13: 100 males). In the dam lines, the selected males were divided into three groups as an average (A11: 100 males), low (A12: 100 males), and high BW (A13: 100 males). In the dam line, offsprings of males with average and high BW had the highest BW at 42 days of age compared to the low BW group (p<0.05). However, there was no statistically significant difference in BW between the BW groups in the offsprings of the sire line. Offsprings of dam line males with average and higher than average BW had better FCR values. However, there was no significant change in FCR between the offsprings of the sire line BW groups. As a result, it is thought that by preserving the variation at a certain level in future generations, a significant improvement can be achieved in the BW and FCR by selecting heavier males.

Evaluation of cardiac status, ascites related factors and growth performance of five commercial strains of broiler chickens

The aim of the current study was to evaluate cardiac status, ascitessusceptibility, thyroid hormones, some hematological parameters andperformance of five commercial broiler strains.Chicks were selected from strains of Cobb, Hubbard, Ross 308, Arbor Acres, and Arian (Iranian commercial broiler strain). Management and nutritional conditions were the same for all strains. Ascites related factors, and growth performancewere measured. The highest and lowest, RV weight/live weight at 21 day of age were related to Arian and Ross 308 strains, respectively (p <0.05). The TV weight, TV weight/live weightand the RV weight/live weight were significantly different between various strains at 49 and 54 days of age(p <0.05). Strain had no effect on RV/TV.Performance, T3and T4hormones, hematological parameters, andmortalitieswere not significantly different among the strains(p >0.05). Ascites mortalities in the Ross 308 was zero; however, it had no significant difference with other strains (p >0.05).It was concluded that, based on performance and physiological status, even though considered broiler strains did not differ significantly because of the same genetic programs probably, but according to the prices and market conditions each can be selected for breeding.(AU)

Evaluation of cardiac status, ascites related factors and growth performance of five commercial strains of broiler chickens

The aim of the current study was to evaluate cardiac status, ascitessusceptibility, thyroid hormones, some hematological parameters andperformance of five commercial broiler strains.Chicks were selected from strains of Cobb, Hubbard, Ross 308, Arbor Acres, and Arian (Iranian commercial broiler strain). Management and nutritional conditions were the same for all strains. Ascites related factors, and growth performancewere measured. The highest and lowest, RV weight/live weight at 21 day of age were related to Arian and Ross 308 strains, respectively (p 0.05). Ascites mortalities in the Ross 308 was zero; however, it had no significant difference with other strains (p >0.05).It was concluded that, based on performance and physiological status, even though considered broiler strains did not differ significantly because of the same genetic programs probably, but according to the prices and market conditions each can be selected for breeding.

Suplementação de minerais e vitaminas em dietas de frangos de corte: efeito sobre desempenho e qualidade óssea / Supplementation of minerals and vitamins in broiler diets: effect on performance and bone quality

As diferenças na velocidade de crescimento e na composição de carcaça dos frangos podem exigir níveis mais altos de vitaminas e de minerais com maior biodisponibilidade. O objetivo deste trabalho foi suplementar dietas comerciais para frangos de corte com níveis otimizados de vitaminas e com diferentes fontes minerais para avaliar o efeito sobre o desempenho produtivo, rendimento de carcaça e qualidade óssea. Foram utilizados 1800 pintos de corte machos da linhagem Cobb Slow, divididos em um delineamento inteiramente casualizado em esquema fatorial 2 x 2 (programas vitamínicos - otimizado e comercial Vs fontes de minerais - inorgânicos (sulfatos) e carbo-amino-phospo-chelate, CAPC). No premix vitamínico otimizado foi incluído o metabólito da vitamina D3, 25(OH)D3. As aves e as sobras de ração foram pesadas semanalmente. A análise estatística dos dados foi realizada pelo procedimento GLM do software SAS. A suplementação de dietas com associação de programas vitamínicos otimizados e fonte mineral CAPC resultou em melhor conversão alimentar aos 42 dias de idade (P<0,05). A suplementação com minerais CAPC resultou em menor índice de vermelho (*a) (P<0,05) na musculatura adjacente aos ossos das coxas e sobrecoxas dos frangos de corte quando descongeladas e assadas, indicando menor porosidade óssea. Fontes mais biodisponíveis de minerais permitem reduzir a sua inclusão nas dietas e diminuem o impacto negativo da excreção de minerais e o efeito poluidor sobre o meio ambiente.

Differences in growth rate and carcass composition of broilers may require higher levels of vitamins and minerals with higher bioavailability. The aim of this trial was to supplement commercial diets for broilers with optimized levels of vitamins and with different mineral sources to assess the effect on performance, carcass yield and bone quality. A total of 1,800 Cobb Slow male broiler chicks were distributed into a 2 x 2 factorial completely randomized design (vitamin programs - optimized and commercial versus mineral sources - inorganic [sulfates] and carbo-amino-phospho-chelate, CAPC). The vitamin D3 metabolite, 25 (OH) D3, was included in the optimized vitamin premix. Birds and feed leftovers were weekly weighed. Data was subjected to statistical analysis using the GLM procedure of SAS software. Supplementing diets with a combination of optimized vitamin programs and CAPC as mineral source resulted in better feed conversion at 42 days of age (P<0.05). Supplementation with CAPC minerals resulted in a lower red index (*a) (P<0.05) in the adjacent thigh muscles and drumstick bones of broilers when thawed and roasted, indicating less bone porosity. The inclusion rates of mineral sources with higher bioavailability can be reduced, decreasing the negative impact of mineral excretion and the polluting effect on the environment.

Supplementation of minerals and vitamins in broiler diets: effect on performance and bone quality / Suplementação de minerais e vitaminas em dietas de frangos de corte: efeito sobre desempenho e qualidade óssea

Differences in growth rate and carcass composition of broilers may require higher levels of vitamins and minerals with higher bioavailability. The aim of this trial was to supplement commercial diets for broilers with optimized levels of vitamins and with different mineral sources to assess the effect on performance, carcass yield and bone quality. A total of 1,800 Cobb Slow male broiler chicks were distributed into a 2 x 2 factorial completely randomized design (vitamin programs - optimized and commercial versus mineral sources - inorganic [sulfates] and carbo-amino-phospho-chelate, CAPC). The vitamin D3 metabolite, 25 (OH) D3, was included in the optimized vitamin premix. Birds and feed leftovers were weekly weighed. Data was subjected to statistical analysis using the GLM procedure of SAS software. Supplementing diets with a combination of optimized vitamin programs and CAPC as mineral source resulted in better feed conversion at 42 days of age (P<0.05). Supplementation with CAPC minerals resulted in a lower red index (*a) (P<0.05) in the adjacent thigh muscles and drumstick bones of broilers when thawed and roasted, indicating less bone porosity. The inclusion rates of mineral sources with higher bioavailability can be reduced, decreasing the negative impact of mineral excretion and the polluting effect on the environment.

As diferenças na velocidade de crescimento e na composição de carcaça dos frangos podem exigir níveis mais altos de vitaminas e de minerais com maior biodisponibilidade. O objetivo deste trabalho foi suplementar dietas comerciais para frangos de corte com níveis otimizados de vitaminas e com diferentes fontes minerais para avaliar o efeito sobre o desempenho produtivo, rendimento de carcaça e qualidade óssea. Foram utilizados 1800 pintos de corte machos da linhagem Cobb Slow, divididos em um delineamento inteiramente casualizado em esquema fatorial 2 x 2 (programas vitamínicos - otimizado e comercial Vs fontes de minerais - inorgânicos (sulfatos) e carbo-amino-phospo-chelate, CAPC). No premix vitamínico otimizado foi incluído o metabólito da vitamina D3, 25(OH)D3. As aves e as sobras de ração foram pesadas semanalmente. A análise estatística dos dados foi realizada pelo procedimento GLM do software SAS. A suplementação de dietas com associação de programas vitamínicos otimizados e fonte mineral CAPC resultou em melhor conversão alimentar aos 42 dias de idade (P<0,05). A suplementação com minerais CAPC resultou em menor índice de vermelho (*a) (P<0,05) na musculatura adjacente aos ossos das coxas e sobrecoxas dos frangos de corte quando descongeladas e assadas, indicando menor porosidade óssea. Fontes mais biodisponíveis de minerais permitem reduzir a sua inclusão nas dietas e diminuem o impacto negativo da excreção de minerais e o efeito poluidor sobre o meio ambiente.

Effect of Early Post-Hatch Feeding Time on Growth and Carcass Performance of Mule Ducks Reared Intensively in the Humid Tropics

A prolonged period without feed access negatively impacts the growth and development of poultry. This study evaluated the effect of early post-hatch feeding times on the growth and carcass performance of Mule ducks reared intensively in the tropics. A total of 48 Mule ducklings were obtained from a local hatchery and assigned in a completely randomized design to 4 treatments based on 4 feeding regimes, (T) as follows: T1 3hrs, T2 24hrs, T3 36hrs and T4 48hrs post-hatch. On day 1 the ducklings were individually weighed, followed by weekly weighing until harvest at 63 days. Feed and feed refusal was measured daily for a period of 63 days. At harvest the body weight at slaughter, eviscerated and hot carcass weight, as well as the initial pH and pH24 of the breast, leg, and thigh quarters was evaluated. Weights of the organs of the gastrointestinal tract were then taken. The feed conversion ratio (FCR), feed intake and meat: skin: bone ratio was calculated. At 0-7 days cumulative feed intake and FCR was influenced by treatment (p=0.022, p=0.026; respectively). Body weight at slaughter ranged from 2969-3382.5g. Treatment did not affect the weights of the bone, fat, muscle and skin, of the breast quarter (p=0.698, p=0.893, p=0.940; respectively). However, weight of the bone for the leg and thigh quarter differed among treatments. A lower pH24 was observed for both breast and leg and thigh quarters. The study suggests that early post-hatch feeding at 3-48hrs does not affect the performance of Mule ducks.(AU)