Aportes nutricionais na recria a pasto e sistemas na terminação de tourinhos Nelore: metabolismo, desempenho e qualidade da carne
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2019-10-22
Autores
Ferrari, Adriana Cristina [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo do trabalho foi avaliar o efeito da suplementação sobre o desempenho, utilização de nitrogênio e mitigação de gás metano (CH4) em tourinhos Nelore na recria e, como o histórico de suplementação influencia no desempenho, expressão gênica e qualidade da carne desses animais. O trabalho foi dividido em experimento de recria e em experimento de terminação. Na recria, foram utilizados 60 tourinhos Nelores com idade média de 12 meses distribuidos em 9 piquetes de capim Marandú recebendo três tipos de suplementação a 0,3% PC: FS) suplemento múltiplo (proteico – energético) com farelo de soja; SE) suplemento energético e SD) suplemento múltiplo com DDG. Concomitante a este experimento, seis animais castrados e fistulados no rúmen, foram distribuidos nos três tratamentos para avaliação de consumo dos nutrientes, parâmetros ruminais e balanço e eficiência microbiana em delineamento quadrado latino duplo incompleto. Dentre os 60 animais destinados a avaliação de desempenho, foram escolhidos 18 tourinhos para determinação de produção de CH4. A análise estatística utilizada no experimento de desempenho e produção de gás metano foi o delineamento interamente casualizado. No experimento de terminação, foram utilizados 80 tourinhos Nelore que, na recria, receberam quatro tipos de suplementos: MM) mistura mineral ad libitum; FS; SE e SD foram terminados em dois sistemas. Dez animais de cada tratamento permaneceram em pasto e receberam suplemento de alto consumo a base de milho e DDG e, os outros dez animais de cada tratamento foram alocados em confinamento convencional. Foram feitas as avaliações de consumo e digestibilidade dos nutrientes, desempenho animal, características de carcaça, qualidade da carne e expressão de genes relacionados ao metabolismo de lipídeos. Foi utilizado o delineamento experimental inteiramente casualizado com arranjo fatorial 4x2 analisados em pacote estatístico S.A.S. Para comparação de médias foi utilizado o teste Tukey com nível de significancia p < 0,05. Na recria, os animais alimentados com SD excretaram menos nitrogênio na urina e tiveram menor produção de gás metano por kg de matéria seca consumida que os animais do tratamento SE. Os tratamentos estudados durante a recria não apresentaram diferença no desempenho dos animais, sendo viável a suplementação energética e múltipla com DDG substituindo suplementos múltiplos com farelo de soja. Durante a terminação, os animais terminados em pasto consumiram menos alimento e foram abatidos com menor peso, menor peso de carcaça quante, espessura de gordura porém, apresentaram maior rendimento de carcaça. Animais terminados em confinamento convencional também apresentaram carne com menor força de cisalhamento e maior proporção de ácidos graxos monoinsaturados, que apresentaram melhor qualidade da carne que animais terminados em pasto. Os animais terminados em pasto apresentaram menor expressão do fator de transcrição SREBP1c, que influenciou no menor depósito de gordura desses animais.
The aim of this study was to evaluate the effect of supplementation on performance, nitrogen use and methane gas (CH4) mitigation in Nellore bulls on post weaning phase and, investigate how the history of supplementation influences performance, gene expression and meat quality of these bulls. The study was divided into post weaning experiment and finishing experiment. On post weaning phase, 60 Nellore’s bulls with an average age of 12 months, were distributed in 9 paddocks receiving three types of supplementation at 0.3% PC: SB) multiple supplementation (protein - energy) with soybean meal; ES) energy supplement and SD) multiple supplement with DDG. Concomitant to this experiment, six castrated and fistulated animals were distributed in three treatments (two animals per treatment) for nutrient intake evaluation, ruminal parameters, nitrogen balance and microbial efficiency in the incomplete double-square Latin design. Among those 60 animals used for performance evaluation, 18 bulls were selected for determination of CH4 production. The statistical analysis used in the methane gas production and performance experiment was randomly designed as the data analysis was performed using the SAS (2008). On finishing experiment, 80 Nellore bulls were used receiving four types of supplements: MM) mineral mixture ad libitum; FS; SE and SD (20 animals per treatment) on post weaning phases were finished in two systems. Ten animals from each treatment keep on pasture and receive high intake supplements based on maize and DDG, and another ten animals from each treatment are allocated in conventional feedlot. Nutrient intake and digestibility, animal performance, carcass characteristics, meat quality and expression of genes related to lipid metabolism were evaluated. The statistical analysis used was randomized designed with a factorial arrangement 4x2 analyzed in the S.A.S. statistical package. For comparison of media, was used Tukey test with significance level p <0.05.During post weaning experiment, animals fed with DS excreted less nitrogen in the urine and had the lowest methane gas production per kg of dry matter intake than ES animals. There was no difference in animal performance, being possible to replace conventional supplements to DDG and energy supplement without negatives results in animal performance. During finishing, the animals at express feedlot had lower intake and were slaughtered with lower body weight, lower carcass weight, fat thickness but higher carcass yield. Animals finishing in conventional feedlot had lower shear force and higher proportion of monounsaturated fat acids, presenting better meat quality than animals finished in express feedlot®. The animals finished in express feedlot have lower expression of the transcription factor SREBP1c, which influenced the lower fat deposition of these animals.
The aim of this study was to evaluate the effect of supplementation on performance, nitrogen use and methane gas (CH4) mitigation in Nellore bulls on post weaning phase and, investigate how the history of supplementation influences performance, gene expression and meat quality of these bulls. The study was divided into post weaning experiment and finishing experiment. On post weaning phase, 60 Nellore’s bulls with an average age of 12 months, were distributed in 9 paddocks receiving three types of supplementation at 0.3% PC: SB) multiple supplementation (protein - energy) with soybean meal; ES) energy supplement and SD) multiple supplement with DDG. Concomitant to this experiment, six castrated and fistulated animals were distributed in three treatments (two animals per treatment) for nutrient intake evaluation, ruminal parameters, nitrogen balance and microbial efficiency in the incomplete double-square Latin design. Among those 60 animals used for performance evaluation, 18 bulls were selected for determination of CH4 production. The statistical analysis used in the methane gas production and performance experiment was randomly designed as the data analysis was performed using the SAS (2008). On finishing experiment, 80 Nellore bulls were used receiving four types of supplements: MM) mineral mixture ad libitum; FS; SE and SD (20 animals per treatment) on post weaning phases were finished in two systems. Ten animals from each treatment keep on pasture and receive high intake supplements based on maize and DDG, and another ten animals from each treatment are allocated in conventional feedlot. Nutrient intake and digestibility, animal performance, carcass characteristics, meat quality and expression of genes related to lipid metabolism were evaluated. The statistical analysis used was randomized designed with a factorial arrangement 4x2 analyzed in the S.A.S. statistical package. For comparison of media, was used Tukey test with significance level p <0.05.During post weaning experiment, animals fed with DS excreted less nitrogen in the urine and had the lowest methane gas production per kg of dry matter intake than ES animals. There was no difference in animal performance, being possible to replace conventional supplements to DDG and energy supplement without negatives results in animal performance. During finishing, the animals at express feedlot had lower intake and were slaughtered with lower body weight, lower carcass weight, fat thickness but higher carcass yield. Animals finishing in conventional feedlot had lower shear force and higher proportion of monounsaturated fat acids, presenting better meat quality than animals finished in express feedlot®. The animals finished in express feedlot have lower expression of the transcription factor SREBP1c, which influenced the lower fat deposition of these animals.
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Palavras-chave
Expressão gênica, Qualidade da carne, Nutrição, Gene expression, Meat quality, Energy supplement