Growth response and carcass composition of hybrid catfish (Hetero-clarias) fed variegated grasshopper (Zonocerus variegatus) Linn meal

Abstract

A feeding trial was conducted to evaluate the suitability of Zonocerus variegatus meal (VGM) in the practical diet of hybrid catfish (Heteroclarias) fingerlings through their growth performance and carcass composition for 70 days. Six isonitrogenous diets were formulated in which VGM was included in the diet at different inclusion levels - D1 (0%), D2 (10%), D3 (20%), D4 (30%), D5 (40%) and D6 (50%). Each treatment had three replicates, eighteen net hapa (0.5 × 0.5 × 1m) were suspended in three outdoor concrete tanks (8m×5×1.5m). The concrete tanks were filled to 5/6 of its volume (40 m3) with filtered and dechlorinated tap water, 20 fish with the initial average weight of 2.17±0.14 were stocked in each hapa. Water temperature and other water quality parameters were monitored daily. Except for the specific growth rate (SGR) where fish fed D3 and D4 were not significantly different (P>0.05), the result showed that fish fed with D4 (30% inclusion) had the highest value in other growth performance indices measured (P< 0.05), while fish fed D6 (50% inclusion) gave the lowest value. There were no significant differences among fish fed D1, D2, and D3. However, they were significantly higher (P< 0.05) than fish fed D5 and D6. The proximate composition result revealed that carcass lipid increased with an increase in the inclusion level of VGM in the diet. It could be concluded that 30% inclusion of VGM can improve growth performance of hybrid catfish without any adverse effect health status, suggesting that VGM could be a suitable ingredient in the diet of hybrid catfish.