Abstract
Chinese perch (Siniperca chuatsi) is one of the economically important freshwater species fish for aquaculture in China. This study aimed to determine the ontogenetic development of the digestive enzyme activity (trypsin, pepsin, amylase, lipase, chymotrypsin and alkaline phosphatase) and related gene expressions of S. chuatsi larvae from hatching to 30 days post-hatching (dph). The larvae were fed with live fry fish twice a day. Results indicated that it was low detection of enzyme activity and gene expression of trypsin, chymotrypsin, lipase, amylase and alkaline phosphatase before mouth opened, the last two enzymes showed an activity close to zero. Different from other carnivorous fish, specific activity and gene expression of trypsin, chymotrypsin and lipase in S. chuatsi larvae were not increased after starting the first feeding. Interestingly, the amylase and alkaline phosphatase specific activity progressively increased over development, indicating that the larvae have certain ability to digest carbohydrates. Pepsin activity and gene expression started to sharply increase after 15 dph, other digestive enzyme activity showed downward trends. The development pattern of digestive enzymes may affect the ability of S. chuatsi to digest the zooplankton, which leads to the formation of unique feeding habit of the S. chuatsi larvae. This study also will provide the necessary theoretical basis for the artificial opening diet of the S. chuatsi larvae.
Effect of β-Glucans in Diets on Growth, Survival, Digestive Enzyme Activity, and Immune System and Intestinal Barrier Gene Expression for Tropical Gar (Atractosteus tropicus) Juveniles
