Serum and tissue thiocyanate concentration in Tilapia (Oreochromis niloticus), fed with cassava peel based diets supplemented with DL-methionine

摘要

A total of 240 mixed sex juvenile (33 g mean weight) Tilapia (O. niloticus) were studied in a 3 x 4 factorial design experiment. The dietary variables were cassava peels (0%, 10%, 20% and 30%) and DL-methionine (0% and 0.4%). Serum thiocyanate, liver thiocyanate and gills thiocyanate levels were significantly increased (P > 0.05) by the dietary intake of cassava peel, methionine and the interaction of cassava peel versus methionine supplementation. The muscle thiocyanate concentration was significantly (P < 0.05) affected by the dietary intake of cassava peel and methionine supplementation but not the cassava peel versus methionine supplementation. While the 30% cassava peel inclusion usually lead to elevated-tissue thiocyanate level, 0.4% methionine supplementation was most effective in the lowering thiocyanate level. Consequently, a 30% cassava peel based diet containing 0.4% methionine supplementation can be formulated to substitute for corn in a tilapia diet.