Replacement of fishmeal by silkworm caterpillar (Anaphe infracta) meal in the practical diets of Heterobranchus bidorsalis

Abstract

An experiment was conducted to evaluate utilization of silkworm caterpillar (Anaphe infracta) meal (SCM) as a replacement for fishmeal in practical diet of Heterobranchus bidorsalis fingerling (M±SE=71 g±0.04g). The fish were fed five isonitrogenous (40% crude protein) and isocaloric (5.2Kcal^-1) diets formulated using the best performance of SCM that was processed under thermally controlled condition (120°C for 12 hours). Fishmeal was replaced at 100%, 75%, 50%, 25% and 0% representing Diets 1 to 5 respectively. The fish was fed for 56 days. The result showed a trend of difference in nutrient utilization as Diet 3 (50:50) recorded a better mean weight gain (MWG) values of 30.09g and better specific growth rate (SGR: 0.64); food conversion ratio (FCR: 0.78); protein efficiency ratio, (PER: 0.74). These differed significantly from other diets (P<0.05). This was probably as a result of better and an appropriate essential amino acid balance in the diet than any other one as SCM is richer in some of these essential amino acid than fishmeal, meat meal and soybean meat. Carcass composition differed significantly with respect to Ash, Ether extract, crude protein and fibre (P<0.05). It was also observed that carcass lipid decreased with decreasing levels of SCM inclusion.

Key words: Replacement, Fishmeal, Silkworm, Heterobranchus bidorsalis