Predição da digestibilidade da matéria seca de rações em coelhos em crescimento
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Data
2011-12-01
Autores
Teixeira, Paulo Sérgio dos Santos [UNESP]
Wechsler, Francisco Stefano [UNESP]
Moura, Ana Silvia Alves Meira Tavares [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Zootecnia
Resumo
O experimento foi realizado com o objetivo de predizer a digestibilidade da matéria seca (MS) de rações para coelhos em crescimento mediante equações baseadas no conceito de entidade nutritiva ideal. Foram usados 100 coelhos do Grupo Genético Botucatu, com 42 dias de idade. Testaram-se 16 rações contendo alimentos volumosos (papel, sabugo de milho, bagaço de cana ou maravalha de pínus), mais milho, farelo de soja, óleo de soja, caulim e sal comum. Os volumosos foram incluídos em quatro níveis, para se obter 22, 28, 34 ou 40% de fibra em detergente neutro (FDN) e 16% de proteína bruta (PB). O experimento foi realizado em duas fases, em delineamento experimental de blocos ao acaso. Observou-se efeito linear positivo da FDN sobre o consumo de MS. As médias de digestibilidade da MS variaram entre 60,10 e 80,78%. Houve efeito linear negativo da FDN, bem como interação do teor de FDN × volumoso, sobre a digestibilidade aparente da MS. Ao contrário dos componentes fibrosos, a proteína bruta PB e o conteúdo celular comportaram-se como entidade nutritiva ideal. Para predizer a digestibilidade da MS, testaram-se três modelos e o melhor baseou-se no teor de conteúdo celular, com digestibilidade verdadeira fixada em 1; outro no teor de FDN, cuja digestibilidade foi predita mediante uma equação empírica; e o terceiro, na perda endógena de conteúdo celular, considerada proporcional ao consumo de MS. A principal dificuldade na formulação de modelos para predizer a digestibilidade aparente da MS em coelhos é estimar com precisão a digestibilidade da FDN e a perda endógena de conteúdo celular. É necessário avaliar em estudos futuros o uso de maiores níveis de fibra nas rações. Para rações com níveis de fibra situados na amplitude deste estudo, recomenda-se usar o modelo 3, que inclui, além da fibra em detergente neutro, a fibra em detergente ácido e a lignina.
The experiment was conducted with the objective of predicting the dry matter (DM) digestibility of rations for growing rabbits, by means of equations based on the concept of ideal nutritive entity. One hundred 42-day-old rabbits from the Botucatu Genetic Group were used. Sixteen rations were tested, containing roughage (paper, corn cobs, sugarcane bagasse or pine shavings), plus corn, soybean meal, soybean oil, kaolin and common salt. Roughages were included at four levels, to obtain 22, 28, 34 or 40% neutral detergent fiber (NDF) and 16% crude protein (CP). The experiment was accomplished in two periods, in a randomized block design. Positive linear effect of NDF on DM intake was observed. The means of DM digestibility varied between 60.10 and 80.78%. There was a negative linear effect of NDF, as well as of the NDF content × roughage interaction on the DM apparent digestibility. Both CP and cell contents behaved as ideal nutritive entity, but the fibrous components did not. To predict DM digestibility, three models were tested; the best model was based on the cell contents, with true digestibility fixed at 1; another on the NDF content, whose digestibility was predicted by means of an empiric equation; and the third one on the endogenous loss of cell contents. The main difficulty in the formulation of models for apparent DM digestibility prediction is to estimate, with precision, NDF digestibility and cell contents endogenous loss. Future studies evaluating higher fiber levels in the diets are needed. For diets with fiber content within the range tested in the present study, model 3, which includes, besides neutral detergent fiber, acid detergent fiber and lignin, is recommended.
The experiment was conducted with the objective of predicting the dry matter (DM) digestibility of rations for growing rabbits, by means of equations based on the concept of ideal nutritive entity. One hundred 42-day-old rabbits from the Botucatu Genetic Group were used. Sixteen rations were tested, containing roughage (paper, corn cobs, sugarcane bagasse or pine shavings), plus corn, soybean meal, soybean oil, kaolin and common salt. Roughages were included at four levels, to obtain 22, 28, 34 or 40% neutral detergent fiber (NDF) and 16% crude protein (CP). The experiment was accomplished in two periods, in a randomized block design. Positive linear effect of NDF on DM intake was observed. The means of DM digestibility varied between 60.10 and 80.78%. There was a negative linear effect of NDF, as well as of the NDF content × roughage interaction on the DM apparent digestibility. Both CP and cell contents behaved as ideal nutritive entity, but the fibrous components did not. To predict DM digestibility, three models were tested; the best model was based on the cell contents, with true digestibility fixed at 1; another on the NDF content, whose digestibility was predicted by means of an empiric equation; and the third one on the endogenous loss of cell contents. The main difficulty in the formulation of models for apparent DM digestibility prediction is to estimate, with precision, NDF digestibility and cell contents endogenous loss. Future studies evaluating higher fiber levels in the diets are needed. For diets with fiber content within the range tested in the present study, model 3, which includes, besides neutral detergent fiber, acid detergent fiber and lignin, is recommended.
Descrição
Palavras-chave
conteúdo celular, equações, fibra em detergente ácido, fibra em detergente neutro, nutrição, proteína bruta, acid detergent fiber, cell content, crude protein, equations, neutral detergent fiber, nutrition
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 40, n. 12, p. 2783-2790, 2011.