Ontogeny of the digestive enzyme activity of the pikeperch (Sander lucioperca) under culture condition

Abstract

The pikeperch (Sander lucioperca) is a species with a high potential for aquaculture and a valuable food with high market acceptance. The aim of the study was to evaluate the functional ontogeny of digestive enzyme of pikeperch from hatching to 45 days-post fertilization, 777 degree-day (DPF, dd) under culture condition. The average total length (TL) of larvae measured at hatching was 3.6 ± 0.4 mm (5 DPF; 67 dd) and at the end of experiment (45 DPF, 777 dd) was 27.1 ± 1.1 mm. The survival rate was 80-90% during the experiment period. Inhibition zimography reveals the presence of nine bands with proteolytic activity in the digestive tract of juvenile pikeperch. Zimography results during the ontogeny revealed that in larvae at 8 DPF (108 dd) and 13 DPF (189 dd), three bands were presented. The variations observed in the enzymatic activity reflected a high amount of total protease activity at 10 DPF (133.5 dd). Regarding pepsin, its activity was observed for the first time at 26 DPF (378.9 dd). Lipase activity remained constant from hatching to 26 DPF (378.9 dd). The highest amount of α-amylase activity was detected at 15 DPF (211.5 dd) and 45 DPF (777 dd). The low lipase enzyme activity suggested that live feeds with low lipid were more suitable than diets containing high lipid levels; larvae had also early capability to digest nutrient-dense diet that was high in protein. According to results the pikeperch larvae possess after the exogenous feeding, a functional digestive system with high activities that indicated the gradual development of the digestive system.