Utilization of different protein sources and intestinal histology in yellowtail snapper, Ocyurus chrysurus

Abstract

Yellowtail snapper (Ocyurus chrysurus) is a marine snapper of the family Lutjanidae that has potential as a mariculture species and as a research model for Lutjanid snapper species, since it is relatively easy to spawn and rear. Hence, there is an interest in identifying the appropriate diets for its culture. The utilization of practical diets and their effects on fish growth performance and body composition are currently poorly understood. To study the effects of practical diets for yellowtail snapper with different protein sources, such as fishmeal (F), poultry meal (P), and soybean meal (SBM), a 14-week growth trial was conducted in juveniles with a mean initial weight of 2.03 ± 0.06 g. The trial included a dose-response in replacing fishmeal with poultry meal (F30, F15:P15, P30, and F15:SMB40), which were formulated to have 40 % protein and 10 % lipid levels. Histological measurements of the distal intestine mucosal length, thickness of the mucosa, lamina propria, submucosa, and serosa, as well as in the histological scoring of the lamina propria folds, connective tissue, and large vacuoles showed no significant differences (p > 0.05) among fish fed F30, P30, and F15:SMB40. Results show no adverse effects on growth performance and intestinal histology in yellowtail snapper juveniles when they were fed diets containing low levels of different protein sources and high levels of soybean meal. While diets containing high levels of fishmeal as protein source were best, the results of this study indicate that yellowtail snapper can be grown effectively (i.e. with no significant enteritis or decreases in growth performance) using diets containing a variety of different protein sources allowing for potentially decreased grow-out feed costs and improved overall economic production efficiency.