Abstract

A feeding experiment was conducted in plastic aquaria (46 ´ 38 ´ 28 cm³) to investigate the effect of replacing fish-meal (FM) with crab-meal (CM) on growth, feed utilization and body composition of Heterobranchus longifilis fingerlings with body weight, 3.11 ± 0.56 - 8.48 ± 1.70 g and total length, 73.07 ± 4.99 - 98.69 ± 7.64 mm. Fish and crab-meal were separately used to produce feeds containing 30, 35 and 40% crude protein (CP) and fed to fish for 10 weeks at 5% body weight. The results show that fish fed with 40% CP fish-meal diet had the best growth as indicated in mean weight gain, 6.99 ± 1.70 g; specific growth rate, 4.05 ± 0.19% day^-1; feed conversion ratio, 1.12 ± 0.06 and protein efficiency ratio of 2.28 ± 0.12. Diets with FM performed better than CM diets. Percentage survival rate for FM and CM containing diets varied between 91.0 ± 1.63 and 100% and the condition of fish was not significantly different (P > 0.05). Apart from whole body levels of CP in FM fed fish, moisture and fat contents were unaffected by dietary treatments. Deficiency in some essential amino acids and higher dietary ash levels in CM probably impaired effective utilization of these diets compared to FM. Crab-meal diets show appreciable performance and could have potential use as a partial replacer of FM at a particular level.

Key words: Heterobranchus longifilis, fish-meal, replacement crab-meal, growth, food utilization.