Effects of supplementing methionine hydroxy analogue in soybean meal and distiller’s dried grain-based diets on the performance and nutrient retention of rainbow trout [Oncorhynchus mykiss (Walbaum)]

Two experiments were conducted to evaluate the effects of supplementingmethionine hydroxyanalogue (MHA) on the performance, body composition, and nutrition retention of rainbow trout. In experiment 1, a 2 4 factorial arrangement with two MHA supplemental levels (with and without) and four ¢sh meal replacement levels (25%,50%,75%, and100%, replacedwith soybeanmeal (SBM) andwheat gluten) was used. A ¢sh meal diet was included as a control. Results showed that ¢sh meal replacement levels had signi¢cant e¡ects on ¢shweight gain (WG), feed conversion ratio (FCR), body moisture, crude protein, crude fat, and ash (Po0.05). In experiment 2, a ¢sh meal reference diet and seven other diets were made using SBM and distiller’s dried grain with solubles supplemented with 0, 0, 0.55, 1.1, 1.65, 2.2, and 2.75 gMHA kg 1 diet to replace 50% of ¢sh meal. WG, FCR, and apparent retention of crude protein and phosphorus were signi¢cantly improved in rainbow trout fed the diet containing 1.65 gMHA kg 1 diet compared with ¢sh fed an equivalent diet without MHA.