Avaliação de diferentes estratégias de formulação de dietas com redução de proteína bruta para frangos de corte
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Data
2023-05-10
Autores
Kareem, Damilola Uthman
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Universidade Estadual Paulista (Unesp)
Resumo
A composição nutricional das dietas das aves pode variar dependendo da disponibilidade de ingredientes, impactando potencialmente o desempenho dos frangos de corte, especialmente quando alimentados com dietas com proteína bruta (PB) reduzida. Um total de 2.304 pintos de corte Ross 308, machos, com um dia de idade, foram arranjados em esquema fatorial 3 x 3. As aves foram alimentadas com ração inicial padrão de 0 a 7 dias. No d 8, elas foram distribuídas aleatoriamente em nove tratamentos de oito repetições com 32 aves cada. As dietas experimentais foram elaboradas a partir de três combinações de ingredientes (milho; trigo-milho; sorgo-trigo) com três níveis de PB (Controle; Moderado [controle menos 20 g/kg PB]; forte redução [controle menos 40 g/kg PB]) na fase I (230, 210 e 190 g/kg PB), na fase II (215, 195 e 175 g/kg PB) e na fase final (205, 185 e 165 g/kg PB). A conversão alimentar (FCR) foi semelhante e melhor para as aves alimentadas com proteína moderada durante a fase inicial de crescimento (8 - 28 d), mas piorou à medida que os níveis de PB diminuíram durante a fase de terminação. Independentemente da dieta, a ingestão de proteína e gordura diminuiu à medida que os níveis de PB na dieta diminuíram, enquanto a deposição de gordura e a eficiência da deposição de proteína e gordura aumentaram. As aves excretaram menos nitrogênio à medida que o nível de PB diminuiu. As dietas à base de milho apresentaram os maiores pesos de carcaça e rendimento de peito para os três níveis de PB, enquanto trigo-milho e sorgo-trigo apresentaram valores semelhantes, apenas nos níveis de PB controle e moderado. A digestibilidade da PB foi maior para dietas à base de milho e trigo-milho e menor para as rações contendo os níveis de PB controle e moderado. As dietas à base de milho tiveram a maior digestibilidade energética, mas a energia digestível das dietas à base de milho e sorgo-trigo foi semelhante. A redução de 40 g proteína bruta por kg de ração resultou em aumento na digestibilidade dos aminoácidos, quando comparado as rações controle e moderada. A ração contendo milho apresentou a melhor (maior) digestibilidade dos aminoácidos em comparação com trigo-milho e sorgo-trigo. O estudo revelou que as aves alimentadas com dietas de trigo-milho ou sorgo-trigo tiveram peso corporal menor, mas semelhante. No entanto, os frangos alimentados com dieta à base de milho registraram a melhor conversão alimentar. Portanto, a redução de 20 g/kg de PB nas dietas de frangos de corte permite a redução da excreção de nitrogênio sem impactar negativamente no rendimento de carcaça, rendimento de peito e deposição de proteína dos frangos de corte.
The nutrient composition of poultry diets can vary depending on ingredient availability, potentially impacting broiler performance, especially when fed as reduced crude protein (CP) diets. A total of 2,304 male, one-day-old Ross 308 broiler chicks were arranged in a 3 x 3 factorial. The birds were fed a standard starter diet from 0 to 7 d. On d 8, they were randomly allotted to nine dietary treatments of eight replicates with 32 birds each. The experimental diets were of three ingredient combinations (Corn; wheat-corn; sorghum-wheat) with three CP levels (Control CP; Moderate CP reduction [control minus 20 g/kg CP]; Strong CP reduction [control minus 40 g/kg CP]) at the grower I (230, 210, and 190 g/kg CP), grower II (215, 195, and 175 g/kg CP), and finisher (205, 185, and 165 g/kg CP) phases. The birds' feed conversion ratio (FCR) was similar and better for those fed control and moderately reduced protein during the early growth stage (8 - 28 d) but worsened as CP levels reduced during the finisher phase. Regardless of the diet, protein and fat intake decreased as dietary CP levels decreased, while fat deposition, and ratio of protein and fat deposition to intake increased. Birds excreted less nitrogen as the CP level decreased Birds excreted less nitrogen as the CP level decreased. Corn-based diets had the highest carcass weight and breast yield for all three CP levels, while wheat-corn and sorghum-wheat had similar values but only at control and moderately reduced CP levels. CP digestibility was higher for corn-based and wheat-corn diets and lower for control and moderately reduced CP levels. Corn-based diets had the highest energy digestibility, but the digestible energy of corn-based and sorghum-wheat diets was similar. While the amino acid digestibility is similar and lower for control and moderately reduced CP levels, corn had the best (highest) digestibility compared to wheat-corn and sorghum-wheat. The study revealed that birds fed with wheat-corn or sorghum-wheat diets had lower but similar BWG, and irrespective of the dietary composition, there is no difference in BWG up to 20 g/kg CP reduction. However, the broilers fed a corn-based diet recorded the lowest (best) FCR. Therefore, the reduction of 20 g/kg of CP in broiler chickens’ diets allows the reduction of nitrogen excretion without negatively impacting the broiler chickens’ carcass yield, breast yield, and protein deposition.
The nutrient composition of poultry diets can vary depending on ingredient availability, potentially impacting broiler performance, especially when fed as reduced crude protein (CP) diets. A total of 2,304 male, one-day-old Ross 308 broiler chicks were arranged in a 3 x 3 factorial. The birds were fed a standard starter diet from 0 to 7 d. On d 8, they were randomly allotted to nine dietary treatments of eight replicates with 32 birds each. The experimental diets were of three ingredient combinations (Corn; wheat-corn; sorghum-wheat) with three CP levels (Control CP; Moderate CP reduction [control minus 20 g/kg CP]; Strong CP reduction [control minus 40 g/kg CP]) at the grower I (230, 210, and 190 g/kg CP), grower II (215, 195, and 175 g/kg CP), and finisher (205, 185, and 165 g/kg CP) phases. The birds' feed conversion ratio (FCR) was similar and better for those fed control and moderately reduced protein during the early growth stage (8 - 28 d) but worsened as CP levels reduced during the finisher phase. Regardless of the diet, protein and fat intake decreased as dietary CP levels decreased, while fat deposition, and ratio of protein and fat deposition to intake increased. Birds excreted less nitrogen as the CP level decreased Birds excreted less nitrogen as the CP level decreased. Corn-based diets had the highest carcass weight and breast yield for all three CP levels, while wheat-corn and sorghum-wheat had similar values but only at control and moderately reduced CP levels. CP digestibility was higher for corn-based and wheat-corn diets and lower for control and moderately reduced CP levels. Corn-based diets had the highest energy digestibility, but the digestible energy of corn-based and sorghum-wheat diets was similar. While the amino acid digestibility is similar and lower for control and moderately reduced CP levels, corn had the best (highest) digestibility compared to wheat-corn and sorghum-wheat. The study revealed that birds fed with wheat-corn or sorghum-wheat diets had lower but similar BWG, and irrespective of the dietary composition, there is no difference in BWG up to 20 g/kg CP reduction. However, the broilers fed a corn-based diet recorded the lowest (best) FCR. Therefore, the reduction of 20 g/kg of CP in broiler chickens’ diets allows the reduction of nitrogen excretion without negatively impacting the broiler chickens’ carcass yield, breast yield, and protein deposition.
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Palavras-chave
Aminoácidos, Protein deposition, Nitrogen excretion, Amino acids, Protein, Gorduras na dieta