Effects of live food and dietary digestive enzymes on the efficiency of microdiets for seabass ( Dicentrarchus labrax) larvae

Abstract

The effects of live food ( Artemia nauplii) and dietary supplementation of digestive enzymes (pancreatin) on ingestion and assimilation of dry microdiet (MD) and nutrient deposition and larval growth were studied in 20–39 day old seabass ( Dicentrarchus labrax) larvae. Four treatments were tested at each age: (i) MD with Artemia nauplii; (ii) MD supplemented with digestive enzymes and Artemia nauplii; (iii) MD supplemented with digestive enzymes; (iv) MD without enzyme supplementation. Ingestion and assimilation of the MD were tested by trials using a radioisotope method. Another trial was conducted to investigate the effect of MD in larval growth and body composition. Addition of Artemia to MD-fed seabass larvae positively affected rates of assimilation and growth, regardless of the age of the fish. No effect of dietary enzymes on MD assimilation or larval growth was observed. However, addition of Artemia and dietary enzyme supplementation affected lipid and protein deposition in the larvae. In conclusion, live Artemia given together with MD enhanced the efficiency of MD in seabass, by promoting the assimilation and deposition of dietary nutrients in the larval body. The factors responsible in Artemia and the possible mechanisms involved are discussed.