Asian-Pacific Aquaculture 2019

June 19 - 21, 2019

Chennai Tamil Nadu - India

CHANGES IN DIGESTIVE ENZYME DURING THE INITIAL ONTOGENY OF PEARLSPOT Etroplus suratensis

Ezhilarasi. V*., Felix. S., Samuel moses .T.L.S., Cherylantony., and Aruna. S.
*Dr. M.G.R. Fisheries college and Research Institute, Ponneri - 601 204, India
Tamil Nadu Dr. J. Jayalaithaa Fisheries University, Nagapatinum- 611 001, India
ezhilarathana@gmail.com
 

A study was performed in order to understand the development of digestive physiology during the initial ontogeny of pearlspot (E. suratensis) for which the activity of specific and total activity of different pancreatic (trypsin, chymotrypsin, amylase and lipase), gastric (protease) and intestinal (alkaline phosphatase) enzymes from hatching to 60 days post hatch (dph) was determined by means of biochemical analysis. The larvae were reared at 28.2 ± 0.4oC with rotifer from mouth opening (4 dph) until 15 dph. Furthermore, they were reared by feeding with commercial microparticulated feed (200µ) from 20 to 60 dph.  Enzyme activities for amylase and lipase activity were detected before the onset of exogenous feeding, indicating that these enzymes were genetically pre-programmed. Our results showed that the activity of amylase was detected from the first day increasing at 5dah and reaching their maximum activity at 30 dph. The Protease activity of pearlspot was firstly detected at 30 dph, indicating the appearance of functional gastric gland. Alkaline phosphatase specific activity was detected from hatching onward, showed marked increase and reached a maximum activity between 13 and 19 dph. Furthermore, the lipase activity is detected on 3 dph and keeps decreasing and reached maximum on 20 dph.  Accordingly, the larvae of Pearlpsot possess a functional digestive system before the onset of exogenous feeding and the digestive capacity gradually increases as development progresses. The abrupt increase in alkaline phosphatase activity between 10 and 20 dph demonstrates onset of juvenile-like digestive mode in pearlspot larvae. Based on these results, it is concluded that E suratensis has a great capacity to digest all kinds of food items included artificial feed and completes its digestive enzymatic machinery from day 10 after hatching, therefore is recommended to perform the transition from live feed to inert feed at 15 dph.