Effect of dietary Houttuynia cordata leaf meal and leaf extract on the growth performance, nutrient utilization and expression of IGF-I gene in Labeo rohita.

Abstract

A 60‐day feeding trial was conducted to evaluate the effects of feeding Houttuynia cordata leaf meal and extract on the growth performance, nutrient utilization and expression of insulin‐like growth factor‐I (IGF‐I) in Labeo rohita fingerlings. Two hun‐dred seventy fingerlings were randomly distributed in six experimental groups in trip‐licates. Six isonitrogenous (350 g/kg CP) and isocaloric (17 MJ/kg DE) diets were prepared with graded levels of leaf meal (LM) and leaf extract (LE), namely C (control, without LE and LM), LE‐0.25 (2.5 g/kg LE), LE‐0.5 (5 g/kg LE), LE‐1.0 (10 g/kg LE), LM‐1.0 (10 g/kg LM) and LM‐2.0 (20 g/kg LM). Significantly (p < 0.05) higher IGF‐I expression, weight gain %, specific growth rate and lower feed conversion ratio were observed in LM‐1.0 followed by LE‐1.0 group compared to control group. Higher pro‐tease activity was observed in LE‐1.0 compared to other experimental groups, while no significant changes were found for amylase and lipase activities. Compared to control, muscle alanine aminotransferase and aspartate aminotransferase activities were significantly higher in treatment groups except for LM‐2.0. These results sug‐gest that either LE‐1.0 or LM‐1.0 can be supplemented in the diet to improve the growth of L. rohita. However, the supplementation of 10 g H. cordata leaf meal/kg feed can be the better option considering the cost of extraction.