Digestibilidade e balanço de nitrogênio em ovinos alimentados à base de dietas com elevado teor de concentrado e níveis crescentes de polpa cítrica peletizada
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Data
2003-12-01
Autores
Henrique, Wignez
Sampaio, Alexandre Amstalden Moraes [UNESP]
Leme, Paulo Roberto
Alleoni, Guilherme Fernando
Lanna, Dante Pazzanese Duarte
Malheiros, Euclides Braga [UNESP]
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Editor
Sociedade Brasileira de Zootecnia
Resumo
O experimento foi realizado com o objetivo de determinar os coeficientes de digestibilidade, a ingestão de nutrientes e o balanço de nitrogênio de dietas com 20% de silagem de milho e 80% de concentrado e 0, 25, 40 e 55% de polpa cítrica na matéria seca total, substituindo o milho em grão. em delineamento de blocos ao acaso, foram utilizados oito cordeiros mestiços, com nove meses de idade e 34 kg de peso, mantidos em gaiolas individuais com dispositivo para separação de fezes e urina. O período de coleta de alimento, sobras, fezes e urina foi de seis dias e a quantidade de alimento oferecido correspondeu à média do consumido nos três últimos dias do período de adaptação. O experimento foi desenvolvido em duas fases, utilizando-se os mesmos animais, que foram distribuídos em blocos pelo peso. Os resultados foram analisados por regressão polinomial. Houve aumento linear nos coeficientes de digestibilidade aparente da proteína bruta e da fibra em detergente ácido, com o aumento da participação da polpa cítrica na dieta. Os demais coeficientes de digestibilidade não diferiram entre si e foram, respectivamente: 71,8; 73,3; 77,2; 63,5; e 72,2%; para matéria seca, matéria orgânica, extrato etéreo, fibra em detergente neutro e hemicelulose. O teor médio de nutrientes digestíveis totais foi de 72,39%. Houve aumento linear da ingestão de matéria seca e de nutrientes digestíveis totais por dia e por peso metabólico, com o aumento de polpa cítrica na dieta. O mesmo ocorreu com a quantidade de nitrogênio ingerido, absorvido, urinário e retido. O aumento da participação da polpa cítrica peletizada até 55% da matéria seca da dieta, substituindo o grão de milho, implicou em melhor aproveitamento da fibra e eficiência no metabolismo do nitrogênio.
The experiment was developed at Instituto de Zootecnia in São José do Rio Preto, SP, and the objective was to evaluate the digestibility coefficients, the nutrients intake, and the nitrogen balance of diets with 20% of corn silage and 80% of concentrate and 0, 25, 40 and 55% of citrus pulp in total dry matter, replacing corn grain. Eight crossbred lambs, with nine months of age and 34 kg of liveweight, were fed in individual cages, where feces and urine could be separated. During six days, feed, orts, feces and urine were weighed and sampled. The amount of feed offered was the mean of the intake in the last three days of the adaptation period. The experiment consisted of two phases, using the same animals, which were blocked by liveweight. Data were analyzed by regression. There was linear increase in the apparent digestibility coefficients of the crude protein and of the acid detergent fiber with higher levels of citrus pulp. The digestibility coefficients did not differ and means were, respectively: 71.8, 73.3, 77.2, 63.5, and 72.2%, for dry matter, organic matter, ether extract, neutral detergent fiber and hemicellulose. The total digestible nutrients mean was 72.39%. Increasing citrus pulp in the diet caused a linear and significant increase of dry matter and total digestible nutrients intake by day and by metabolic weight. Similar effects were observed for the amount of ingested, absorbed, urinary and retained nitrogen. An increasing proportion of citrus pulp up to 55% of the dietary dry matter, replacing corn grain, resulted in improvement of the fiber utilization and of the efficiency of nitrogen metabolism.
The experiment was developed at Instituto de Zootecnia in São José do Rio Preto, SP, and the objective was to evaluate the digestibility coefficients, the nutrients intake, and the nitrogen balance of diets with 20% of corn silage and 80% of concentrate and 0, 25, 40 and 55% of citrus pulp in total dry matter, replacing corn grain. Eight crossbred lambs, with nine months of age and 34 kg of liveweight, were fed in individual cages, where feces and urine could be separated. During six days, feed, orts, feces and urine were weighed and sampled. The amount of feed offered was the mean of the intake in the last three days of the adaptation period. The experiment consisted of two phases, using the same animals, which were blocked by liveweight. Data were analyzed by regression. There was linear increase in the apparent digestibility coefficients of the crude protein and of the acid detergent fiber with higher levels of citrus pulp. The digestibility coefficients did not differ and means were, respectively: 71.8, 73.3, 77.2, 63.5, and 72.2%, for dry matter, organic matter, ether extract, neutral detergent fiber and hemicellulose. The total digestible nutrients mean was 72.39%. Increasing citrus pulp in the diet caused a linear and significant increase of dry matter and total digestible nutrients intake by day and by metabolic weight. Similar effects were observed for the amount of ingested, absorbed, urinary and retained nitrogen. An increasing proportion of citrus pulp up to 55% of the dietary dry matter, replacing corn grain, resulted in improvement of the fiber utilization and of the efficiency of nitrogen metabolism.
Descrição
Palavras-chave
Corn silage, Intake, pectin, total digestible nutrients, Consumo, nutrientes digestíveis totais, Silagem de milho, Pectina
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 32, n. 6, p. 2007-2015, 2003.