Fish Physiology and Biochemistry 27: 61–69, 2002. © 2004 Kluwer Academic Publishers. Printed in the Netherlands. 61 Digestive enzymes profile of Solea senegalensis post larvae fed Artemia and a compound diet L. Ribeiro 1 , J.L. Zambonino-Infante 2 , C. Cahu 2 and M.T. Dinis 1 1 Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, 8000 Faro, Portugal (E-mail: mribeiro@ualg.pt); 2 Unit´ e Mixte de Nutrition de Poissons INRA-IFREMER, IFREMER, B.P. 29280 Plouzan´ e, France Accepted: October 31, 2003 Key words: alkaline phosphatase, amylase, flatfish, growth, leucine-alanine peptidase, pepsin, survival, trypsin, weaning Abstract The objective of this experiment was to analyse the digestive enzyme profile of Solea senegalensis post larvae fed two diets, live Artemia sp. metanauplii and ICES diet. The experiment lasted 46 days and the ICES diet group was co-fed with a decreasing percentage of Artemia sp. for 39 days. Post larvae were fed twice a day and the amount of food supplied was determined based on the predicted maximum growth attainable. The Artemia treatment exhibited higher growth and survival rates than the ICES treatment. Trypsin, amylase, pepsin, alkaline phosphatase and leucine-alanine peptidase activities (specific activity: U mg protein −1 ; segmental activity: U larva −1 ) were measured in the post larvae digestive tract. Amylase secretion was significantly higher in the ICES treatment, while trypsin secretion was lower. Alkaline phosphatase was adversely and significantly affected by the ICES diet. Leucine-alanine peptidase specific activity was higher in the ICES treatment indicating a delay in the enterocyte maturation also evidenced by the enterocyte maturation index. Alkaline phosphatase and amylase segmental activ- ity had a good correlation with larval growth rate, and may function as a nutritional indicator. This study suggests that compound diet can be included in the feeding sequences of sole larvae as early as 36 day post hatching (697 degree days). Introduction Senegalese sole (Solea senegalensis) is a Mediter- ranean species with a great potential for aquaculture. Although advances have been made in the culture of this species (Cañavate and Fernandez–Díaz 1999), weaning is still identified as a bottleneck for sustain- able production (Dinis et al. 1999). For many marine finfish species the transition from live food to a commercial diet is still a difficult step to go beyond. A commercial diet that would improve weaning efficiency and reduce the expensive period of live food dependence would be of great benefit in marine finfish culture (Watanabe and Kiron 1994). Although a great deal of research has gone into the de- velopment of artificial diets, no compound diets have been developed that can match the growth and sur- vival rates obtained with live food in the early life stages (Watanabe and Kiron 1994). Studies on seabass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) have reported that larvae do eat compound diets (Walford and Lam 1993; Yúfera et al.1995), sug- gesting that differences in growth and survival rates between fish fed live and compound diets were re- lated to the nutritional value of the feed (Tandler 1985) and/or food digestion, nutrient absorption and metabolism (Segner and Rosh 1992). Over the years, the low digestive capacity of lar- vae (Dabrowski 1984) and the absence of a functional stomach before metamorphosis have been pointed out as factors responsible for a poor performance on com- pound diets (Watanabe and Kiron 1994). However, more recent studies reported that larvae do possess di- gestive capacity to digest the food (Zambonino-Infante