The use of alternative feedstuffs in animal diet, such as residues derived from the biodiesel production aims to increase productivity and reduce costs in animal production. Them aim of this study was to evaluate the substitution effect of 0, 22, 44 and 64% of soybean meal protein by Crambe cake (Crambe abyssinica Hochst) protein in lamb diet. In the in vivo experiment, 20 lambs were used and evaluated the apparent digestibility, nitrogen balance and voluntary DM intake. The replacement of the protein resulted in a linear decrease in apparent digestibility coefficient (ADC) of dry matter (DM), organic matter (OM), ether extract (EE), gross energy (GE), acid detergent fiber (ADF), neutral detergent fiber (NDF), cellulose (CEL) and the percentage of total digestible nutrients (TDN), which resulted in decreased daily DM intake. The blood level of urea, glucose, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were not affected. In vitro gas production technique (GP) evaluation of diets showed a significantly decrease (P<0.05) of the total gas and methane production without altering the true degradability of DM and OM and the partition factor (PF). Replacement of soybean meal protein by the Crambe cake protein decreased digestibility of the fiber fraction of the diet, the voluntary intake of DM and methane, without altering rumen fermentation. Crambe cake can be utilized as lamb's food, because, despite reduced intake, assure a large energy intake and similarity to soybean meal protein.
Co-product; digestibility; enteric methane; sheep; sustainability