Abstract
The striped murrel (Channa striata) is highly priced commercially important species targeted for aquaculture diversification in India due to consumer preference, medicinal benefits, rapid growth rate, and adaptability to high-density farming, facilitated by its air-breathing ability. However, the high mortality rate during larval rearing poses a significant challenge to the commercial production of this species. A comprehensive understanding of the nutrient utilization capacity during larval development will aid in formulating suitable feed and feeding strategies. The capacity of C. striata larvae to utilize carbohydrates during ontogenetic development (up to 35 days post-hatching) was investigated by assessing the expression patterns and activity levels of pancreatic α-amylase. For this purpose, a 1014 bp long partial α-amylase cDNA was isolated from C. striata, which showed 85% identity with Channa argus amylases. The expression level of α-amylase increased significantly (p < 0.05) between 3 and 9 days after hatching but subsequently decreased until the end of the experiment. The activity of α-amylase peaked at 7 days after hatching and decreased gradually thereafter. In this study, we also investigated the expression of growth hormone (GH), insulin-like growth factor I (IGF-I), and insulin-like growth factor-binding protein (IGFBP). Growth-related genes were expressed just after hatching and exhibited a dynamic trend across various developmental stages. The specific growth rate for total length was 6.39%/day, with a survival rate of 44% ± 1.8% over the 35-day rearing period. The enhanced activity and expression of α-amylase reinforce the ability of larvae to utilize dietary carbohydrates as energy substrates from early larval stages, which could aid in the development of cost-effective feed formulation for this species.