Exogenous proteases from seafood processing waste as functional additives in rainbow trout aquaculture

Abstract

Previous studies about enzyme additives for salmonids employed commercial proteases from bacteria, but research obtaining such enzymes from other organisms are scarce. We aimed to increase digestive protease activity in Oncorhynchus mykiss, by analysing potential sources of exogenous proteases generated from different seafood processing waste. To date, there is no information regarding the influences that exogenous enzymes have on the activity and integrity of endogenous enzymes in salmonids. The compatibility and interaction between endogenous and exogenous proteases were evaluated through protein hydrolysis and electrophoresis. We also evaluated the capacity of two types of microcapsules (Alginate–Chitosan and Alginate–Chitosan–Bentonite) to protect the protease activity after being exposed to the gastric environment of trout. The seafood wastes had activities around 0.23–2.53 U/ml at 15°C. Among all the exogenous proteases evaluated, P. granulosa's extract showed the best performance, followed by L. santolla's extract. Such extracts increased the protein hydrolysis to equal or higher levels than the commercial protease and did not alter the integrity of trout proteases. The optimal catalytic function at low temperatures of these extracts might be linked to the habitat of these arthropods. Alginate–Chitosan–Bentonite microcapsules are recommended in preference to Alginate–Chitosan capsules for delivery of enzymes in salmonids because they ensure the activity of exogenous proteases for longer in acid pH (6 vs. 4 h). This research promotes a re‐evaluation of seafood processing wastes through the production of a potentially functional additive that may improve trout protein digestion.

Efectos del metabisulfito de sodio sobre la actividad y composición proteásica de los extractos enzimáticos de Pleoticus muelleri

“…El rendimiento de actividad enzimática estimado por kilogramo de cabezas fue significativamente mayor para langostinos sin MBS tanto para proteasas acidas como alcalinas (5.610,37 ± 3.247,138 U kg -1 y 6.158,63 ± 872,580 U kg -1 respectivamente). Sin embargo, a pesar del efecto negativo del tratamiento con MBS sobre las enzimas de langostino, los valores de rendimiento por kilogramo de cabezas obtenidos (807,41 ± 201,737 U kg -1 para proteasas acidas y 2.056,78 ± 528,526 U kg -1 para proteasas alcalinas) indican que las mismas representan una interesante fuente de enzimas para elaborar coagulantes lácteos, hidrolizados proteicos y aditivos enzimáticos para alimentación animal (Pereira y Fernández-Gimé-nez 2016Rodríguez et al 2017Rodríguez et al , 2018Rodríguez et al , 2021Pereira et al 2018Pereira et al , 2020aPereira et al , 2020bPereira et al , 2021.…”

“…En trabajos previos se ha demostrado que P. muelleri es una fuente importante de biomoléculas y subproductos tales como suplementos enzimáticos para alimentos, coagulantes lácteos e hidroli- I n p r e s s zados proteicos (Pereira y Fernández-Giménez 2016Rodríguez et al 2017Rodríguez et al , 2018Pereira et al 2018Pereira et al , 2020aPereira et al , 2020bPereira et al , 2021Rodríguez et al 2021). Es por ello que resulta fundamental contar con proteasas funcionales que presenten altos niveles de actividad enzimática.…”