Changes of digestive enzymes activity in common carp (Cyprinus carpio) during larval ontogeny

This study was aimed to gain knowledge on the ontogeny of digestive enzymes in common carp larvae at the governmental Warm water Fish Aquaculture Center of Shahid Rajaee in Sari, Mazandaran, Iran. The ontogenetic development of pancreatic (trypsin, chymotrypsin, lipase and α-amylase) and intestinal (alkaline phosphatase and aminopeptidase-N) enzymes were assessed in common carp larvae from first feeding (۳ days post hatching) to ۳۳ days post hatching (dph). The larvae started to feed on rotifers at day ۳ to day ۷. Feeding on a commercial diet was started from day-۸ onwards. Specific trypsin and chymotrypsin activities feed with rotifer were ۰.۰۱۱ U/mg protein and ۰.۰۰۳ U/mg protein at day ۷, respectively then the specific activities feed with dry food reached a maximum level at ۳۳ dph (۰.۰۲۸ U/mg protein and ۰.۰۲۸ U/mg protein, respectively) (P<۰.۰۵) compared to live prey. The elevated alkaline proteases activity can be related to adaptation of larvae to digest protein content in the food. Specific lipase activity was ۰.۰۰۰۶ U/mg protein at ۷ dph then the activity feed with dry food reached a maximum level at ۱۵ dph (۰.۰۰۱۱ U/mg protein) (P<۰.۰۵) compared to live prey. Specific α-amylase activity feed with rotifer was ۸۵.۸۶ U/mg protein on the ۷ dph consequently, its specific activity reached a maximum level at ۱۵ dph (۱۲۸.۷۷ U/mg protein) (P<۰.۰۵). Specific alkaline phosphatase and aminopeptidase N activities feed with rotifer were ۶ U/mg protein and ۰.۰۱۰۶ U/mg protein at day ۷, respectively then the specific activities feed with dry food reached a maximum level at ۳۳ dph (۲۸.۶۶ U/mg protein and ۰.۵۸ U/mg protein, respectively) (P<۰.۰۵) compared to live prey.

Keywords:

Common carp , Pancreatic enzymes , Larval growth , Digestive enzymes , Ontogeny