Replacement of de-oiled rice bran by soaked and fermented sweet potato leaf meal: Effect on growth performance, body composition and expression of insulin-like growth factor 1 in Labeo rohita (Hamilton), fingerlings

A 60-day feeding trial was conducted to determine the growth performance and expression of insulin-like growth factor 1 gene (IGF-I gene) in Labeo rohita fingerlings fed with either raw, soaked or fermented sweet potato leaf meal (SPLM) by completely replacing de-oiled rice bran (DORB), following a completely randomized design. Seven isonitrogenous (30%) and isocaloric (1.8MJ/100g) diets were prepared by replacing DORB with 50% and 100% raw, soaked and fermented sweet potato leaf meal, maintaining DORB-containing diets as a control. Weight gain %, SGR (specific growth rate) and PER (protein efficiency ratio) were significantly (p<0.05) higher when 100% DORB was replaced by fermented SPLM in comparison to other treatment groups. The fermented and soaked SPLM-fed groups had registered with lower FCR value. The expression of growth regulating gene IGF-I mRNA and RNA/DNA ratio was found to be significantly higher (p<0.05) in soaked and fermented SPLM-fed groups. In this study, the body protein and lipid composition did not vary significantly (p>0.05). Hence, the study concludes that the fermented sweet potato leaf meal using Chaetomium globosum can replace 100% DORB in the diet of Labeo rohita without any detrimental effect on growth performance.