Markus Langeland,Jan Erik Lindberg,Torbjörn Lundh*
The activity of the digestive enzymes lipase, α-amylase and disaccharidases (sucrase, maltase, isomaltase and trehalase) was studied in slow-growing and fast-growing groups of farmed Eurasian perch (Percafluviatilis) of different ages.The activity of carbohydrases (disaccharidases and α-amylase), lipase, trypsin and chymotrypsin were also compared in Eurasian perch andArcticcharr (Salvelinusalpinus).No effect was noted of growth rate and age on the digestive enzyme activities in Eurasian perch.Total lipase activity was higher than total combined carbohydrase activity in both species (142.0 vs. 6.2 and 111.0 vs. 2.5 Umg-1 protein for Eurasian perch and Arctic charr respectively; P<0.001 for both). Compared with Arctic charr, Eurasian perch had higher lipase activity in the pancreasand lower lipase activity in the pyloric caeca and mid-intestine. Total chymotrypsin activity was higher than total trypsin activity in both species, whereas total chymotrypsin activity was higher for Arcticcharr than for Eurasian perch (192.8 and 110.2 Umg sample-1 respectively; P<0.001). The high lipase and protease activity, and low carbohydrase activity in both species can be linked to their carnivorous feeding habits. Moreover, Eurasian Perch had a higher total carbohydrase activity than charr, suggesting a greater capacity for digesting carbohydrates, especially starch.