Effect of Dietary Protein on Growth, Survival and Cannibalism of Larval Striped Snakehead, Channa striata (Bloch, 1793)

Abstract

The available commercial feeds in Bangladesh for fish larvae, including striped snakehead, (Channa striata (Bloch, 1793)), lack crude protein content. Therefore, for the proper biological well-being of striped snakehead larvae, formulating a protein-rich diet is necessary. The present experiment aimed to study the effect of three formulated isocaloric diets with varying levels of protein content on growth, survival, cannibalism, and mortality in striped snakehead (29 ± 3 mg of mean weight) weaning by rearing for 4 weeks. Three experimental groups depending on the dietary crude protein (CP 35 %, CP 40 %, and CP 45 %) were done in triplicate. Growth parameters (weight and length gain, specific growth rate, feed conversion ratio, and protein efficiency ratio) indicated better growth and feed utilisation in larvae fed CP 45 %, followed by 40 % and 35 % (P < 0.05). However, survival was not significantly different comparing the experimental groups. The cannibalism was maximum in CP 45 %, compared to 35 % and 40 %, most probably due to higher size heterogeneity, also confirmed by the co-efficient of variation in fish size. The observed mortality (not cannibalism) was higher in the group with lower protein (CP 35%) attributable to comparatively low feed intake and utilisation. Overall, the higher dietary protein levels demonstrated comparatively higher growth, possibly indicating the importance of increased protein content in snakehead larval feed.