Biochemical Characterization and Comparison of Pancreatic Lipases from the Pacific Bluefin Tuna, Thunnus orientalis; Totoaba, Totoaba macdonaldi; and Striped Bass, Morone saxatilis

Abstract

AbstractLipolytic activity from pancreatic crude extracts from the Pacific bluefin tuna (PBT), Thunnus orientalis; totoaba, Totoaba macdonaldi; and striped bass, Morone saxatilis, were biochemically characterized to detect possible differences in the digestive capacity of each fish. The maximum activity was at temperatures ranging from 35 to 45 C and at pH 8.0; the activity decreased significantly at a pH lower than 7.0. Lipases from PBT and totoaba showed an increase in activity with the presence of sodium taurocholate (NaTC; 6 mM). However, no increase in activity could be observed when a mixture of bile salts or natural bile extracts was used in the reaction mixture, which was observed in the presence of NaTC. In contrast, the lipase activity from striped bass increased accordingly when NaCl was added at different levels (0–1.5 M). Calcium was not required in the reaction mixture for any of the fish species tested. We concluded that all three lipases have different physicochemical properties and ionic strength and emulsifier requirements to obtain their maximum activity. Striped bass was far too sensitive to NaCl, while totoaba and PBT were sensitive to NaTC. The differences in activity shown here suggest the possibility of studying the use of different additives on feed formulations to maximize lipase efficiency.