Trypsin restoration time in the pyloric ceca of yellowtail Seriola quinqueradiata

Abstract

The time required for trypsin restoration in the pyloric ceca-pancreatic tissue of yellowtail Seriola quinqueradiata (average body weight 942 g) was estimated. Fish were collected after starvation for 24, 48 or 72 h, and 6 h after being fed after each of the three tested starvation periods. Pyloric ceca isolated together with the pancreas were used for measurements of trypsin activity, quantity and expression rate. In the starved group, trypsin activities after 72 and 48 h starvation were significantly higher than after 24 h. Trypsin quantity, which was estimated by a Western blot test, showed similar results. The expression rate, estimated by reverse transcription polymerase chain reaction, was high after 24 h, but decreased after 48 h starvation. Thus, it was concluded that trypsin reaches the maximum storage level after 48 h starvation. In the fed group, the reduction in trypsin activity was greater when fish were fed after 48 and 72 h starvation periods than after 24 h. Trypsin expression rates 6 h after feeding were higher than before feeding. This indicates that trypsin synthesis is initiated after feeding or trypsin secretion and continues until 48 h of food deprivation. These results indicate that yellowtail of this size require feeding intervals of about 48 h to maximize trypsin storage.

Performance factors, body composition and digestion characteristics of gilthead sea bream (Sparus aurata) fed pelleted or extruded diets

“…This finding indicates that enzyme excretion could be related to the gastric evacuation time as this was shorter for the pelleted diet. A relation of this type has been also suggested by Murashita et al. (2005).…”

“…2005). The timing of enzyme secretion has not been adequately studied for fish, but is expected to depend on several parameters including feed characteristics (Murashita et al. 2005).…”

“…For protease activity, maximum excretion has been reported to occur 4–14 h after feeding (Steffens 1989; Einarsson et al. 1996; Murashita et al. 2005).…”