REPLACEMENT OF FISH MEAL WITH POULTRY OFFAL MEAT IN DIETS FOR HUMPBACK GROUPER Cromileptes altivelis GROW-OUT

Abstract

Fish meal (FM) has traditionally been a major ingredient in fish diets as palatable and high quality protein source. Increasing demand and price as well as uncertain availability of the meal encourage nutritionists to study for alternative sources to replace fish meal in fish diets. Poultry offal meal (POM) is one of the most promising candidates for partial or total replacement of FM in fish diets. Feeding trial was conducted to examine effects of partially replacing FM in diets with POM on growth performance of humpback grouper. Fifteen net cages of 1 x 1 x 1.2 m3, each was stocked with 12 humpback groupers with initial weight of 285 ± 20 g, were set up randomly in seawater. Five isonitrogenous and isocaloric diets were formulated to contain 50% FM (66.40% crude protein) as control diet, 8% POM (65.77% crude protein) + 42% FM, 16% POM + 34% FM, 24% POM + 26% FM, and 32% POM + 18% FM. The fish were fed twice daily to satiation for 20 weeks. The fish fed diet containing 32% POM showed significantly lower (P 0.05) from fish fed the diet containing 12 to 24% POM. Weight gain, feed efficiency, protein retention, total feed intake and survival rate did not differ significantly (P>0.05) among treatments except for fish fed the diet containing 32% POM showed significantly lower (P<0.05) weight gain, feed efficiency and protein retention than the fish fed the diet containing 8% POM. These results suggest that up to 24% FM in humpback grouper grow-out diets can be replaced by POM.