Objective: In fish feeding formulation, high interest has recently been addressed to protein sources alternative to Fish Meal (FM); nevertheless, the response of digestive enzymes to dietary changes is not fully known. To fill this gap, a study was undertaken in rainbow trout (Oncorhynchus mykiss), to explore the effects on intestinal enzymes (trypsin, chymotrypsin, carboxypeptidases A and B, amylase) of three experimental diets, containing a plant protein source (pea protein concentrate-PPC), a microbial protein source (bacterial protein meal-BPM) or a mix of PPC and BPM (MIX), in partial (50%) replacement of FM. Methods: Two feeding regimes (apparent satiation or rationed feeding at 1.4% of the fish wet biomass) and three times (1, 3 and 24 hours) after ingestion were tested. Enzyme activities were measured using conventional biochemical methods for digestive enzymes determinations. Results: PPC administered to satiation lead to not significantly higher protein utilization than FM, as suggested by proteolytic enzymes trypsin, chymotrypsin, carboxypeptidase A. In fish fed rationed regime, PPC induced carboxypeptidase B peak and moderate trypsin increase. BPM stimulated trypsin in fish fed both feeding regimes and carboxypeptidase A in those fed to satiation. MIX diet varied significantly trypsin, carboxypeptidase B and amylase, increasing carboxypeptidase A and decreasing chymotrypsin in fish fed to satiation. Conclusions: Digestive enzyme patterns were generally unaffected by the tested protein sources, suggesting that they could partially replace FM without detrimental effects on rainbow trout digestive processes.
Partial Replacement of Fish Meal with Three Different Protein Sources in Rainbow Trout Oncorhynchus mykiss: Response of Intestinal Digestive Enzymes
Gai F;Caruso G;
2022
Abstract
Objective: In fish feeding formulation, high interest has recently been addressed to protein sources alternative to Fish Meal (FM); nevertheless, the response of digestive enzymes to dietary changes is not fully known. To fill this gap, a study was undertaken in rainbow trout (Oncorhynchus mykiss), to explore the effects on intestinal enzymes (trypsin, chymotrypsin, carboxypeptidases A and B, amylase) of three experimental diets, containing a plant protein source (pea protein concentrate-PPC), a microbial protein source (bacterial protein meal-BPM) or a mix of PPC and BPM (MIX), in partial (50%) replacement of FM. Methods: Two feeding regimes (apparent satiation or rationed feeding at 1.4% of the fish wet biomass) and three times (1, 3 and 24 hours) after ingestion were tested. Enzyme activities were measured using conventional biochemical methods for digestive enzymes determinations. Results: PPC administered to satiation lead to not significantly higher protein utilization than FM, as suggested by proteolytic enzymes trypsin, chymotrypsin, carboxypeptidase A. In fish fed rationed regime, PPC induced carboxypeptidase B peak and moderate trypsin increase. BPM stimulated trypsin in fish fed both feeding regimes and carboxypeptidase A in those fed to satiation. MIX diet varied significantly trypsin, carboxypeptidase B and amylase, increasing carboxypeptidase A and decreasing chymotrypsin in fish fed to satiation. Conclusions: Digestive enzyme patterns were generally unaffected by the tested protein sources, suggesting that they could partially replace FM without detrimental effects on rainbow trout digestive processes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.