Profile of Digestive Enzymes Activity During Early Development of Featherback Chitala chitala (Hamilton, 1822)

Abstract

The ontogenetic development of the key digestive enzymes of featherback Chitala chitala was assayed during the early development. Amylase, lipase, trypsin and chymotrypsin activities were detected on 1 days after hatch (DAH), (during endotrophic stage) but pepsin activity was detected on 12 DAH (exotrophic phase) correlated with the improvement of gastric secretion at the beginning of flexion stage. The gradual shift of alkaline protease activity (trypsin and chymotrypsin) to more efficient acidic digestion indicated a change in the digestive physiology as a result of metamorphosis acquiring the juvenile characteristic during the postflexion or extrophic phase. The initial high level of amylase (i.e. from 1 DAH to 9 DAH) during endotrophic and endoexotrophic feeding stage could be better explained as a result of programmed gene expression. But a constant decrease in activity after the 12 DAH i.e. on the onset of flexion and exotrophic stage of featherback fish in the present study may be possibly due to the developmental changes in the gut morphology and increased protein level in the tissue. These fluctuations of the enzymatic activities in featherback larvae reflect the ability of the fish to adapt with the diet during ontogenetic shift. This information can lead to the possibility of developing an age specific formulated feed for intensive farming of this new candidate species.