The digestive and metabolic enzyme activity profiles of a nonmetamorphic marine fish species: effects of feed type and feeding level

Abstract

We investigated activity levels of metabolic and digestive enzymes in Atlantic wolffish (Anarhichas lupus) and their relationships with growth, ration level, and type of food during the first 50 days after hatch. Newly hatched wolffish were divided among three experimental groups differing in feed and ration (formulated feed in excess (FF), a maintenance ration of Artemia (LA), and Artemia in excess (EA)) that generated different growth rates. A principal component analysis revealed that activities of the glycolytic enzymes lactate dehydrogenase (LDH) and pyruvate kinase (PK) were associated with mass gain, while those of the aerobic enzymes citrate synthase and aspartate aminotransferase (AAT), and digestive enzymes (lipase and trypsin) were related to time (days) after hatch. Food restriction or food type allowed the observation of a direct relationship between the activities of trypsin and those of associated metabolic enzymes AAT and glutamate dehydrogenase in the LA group (Pearson's R of 0.71 and 0.59, respectively), as well as between the activities of amylase and those of LDH and PK (Pearson's R of 0.62 and 0.48, respectively) in the FF group. The adaptative importance of these patterns during early development of wolffish and their relationship to feeding conditions are examined.