Digestive enzyme activities in starved pre-slaughter farmed and wild-captured, Atlantic cod (Gadus morhua)

Summary

Recently, Atlantic cod farming has attracted great interest in the northern Atlantic region, and a commercial cod aquaculture industry is developing. Farmed Atlantic cod has a body composition different from wild-captured cod. The most prominent differences are the higher condition factor, larger liver and smaller head. The main purpose of the present work was to compare activities of some major hydrolytic enzymes in liver and digestive tract of farmed cod, which had been starved 10 and 25 days before slaughter, with the corresponding activities in wild-captured cod. Ten wild-captured and 10 farmed cod (3.1–4.6 kg) were subjected to analyses. It was found that the amount of stomach pepsin activity was significantly lower in farmed cod, whereas the content of tryptic enzyme activities, particularly chymotrypsin, were slightly higher. Due to the high hepato-somatic index (14.4), the farmed cod had a much higher β-d-N-acetylglucosaminidase activity in liver than the wild-captured cod. Increasing the pre-slaughter starving period from 10 to 25 days gave no significant reduction in any of the digestive enzyme activities measured. This indicates that the activities of digestive enzymes in carnivorous species, like cod, remain at high levels even during long time starvation.