Apparent digestibility of crude protein and lipids in Brazilian codling, Urophycis brasiliensis (Kamp, 1858) (Pisces: Gadiformes), fed with partial replacements of soybean meal and meat meal diets

The objective of this study was to determine apparent digestibility of crude protein and lipid in Brazilian codling. Three diets (43% crude protein) were tested: a control diet with fish meal as the main protein source, and two others with partial replacement of fish meal by defatted soybean and meat meal. Fishes were fed daily to satiation, and no mortality was observed during the 14 day-experiment. On days 7 and 14, fish were anesthetized and faeces were obtained by stripping. Apparent crude protein digestibility at day 7 was significantly different between the control group and the groups in which fish meal was replaced. Lipid digestibility showed significant differences between soybean group and meat meal group throughout the trial. The highest digestibility values and the lowest moisture percentages in faeces were found in the control group, suggesting an improved digestion of this diet. Apparent digestibility increased from first to second week in diets with replacements. Brazilian codling can be reared on diets in which up to 30% replacement of the fish meal protein can be replaced by defatted soybean or meat meal. Fish need about two weeks for enzymatic adaptation to these diets.