Effects of exogenous enzymes on apparent nutrient digestibility in rainbow trout (Oncorhynchus mykiss) fed diets with high inclusion of plant-based protein

Effect of protease and phytase supplementation on growth performance and nutrient digestibility of rainbow trout (Oncorhynchus mykiss, Walbaum) fed soybean meal-based diets

“…There are a few studies about the effects on the growth parameters of protease supplementation to soybean meal-based diet in trout. Similarly with our study, Dalsgaard et al (2012) found that there were no differences in growth parameters and FCR with the addition of protease to soybean meal in rainbow trout diet. But, apparent digestibility of protein moderately improved by supplementing protease to soybean meal.…”

“…However, it contains antinutritional factors such as trypsin inhibitors that reduce the digestibility of protein (Cheng & Hardy 2003). Previous studies indicated that protease is capable of decreasing the effect of trypsin inhibitors (Caine et al 1998), improving protein digestibility (Drew et al 2005;Dalsgaard et al 2012) and feed efficiency (Drew et al 2005).…”

Dietary supplementation of exogenous carbohydrase enzymes in fish nutrition: A review

“…On the other hand, exogenous carbohydrase effects on fish performance are still unclear. In some cases, growth performance of several fish species was improved (Ai et al, 2007;Carter et al, 1994;Goda et al, 2012;Kumar et al, 2006b;Lin et al, 2007;Zhou et al, 2013); whereas, in other studies no effects were found (Dalsgaard et al, 2012;Farhangi and Carter, 2007;Ogunkoya et al, 2006;Stone et al, 2003;Yigit and Olmez, 2011). Unquestionably, these studies utilized different fish species with different feeding habits.…”

“…Some of the studies conducted with fish species indicate that there are possibilities for improved nutrient utilization that are not accompanied by increased growth rate (Dalsgaard et al, 2012;Farhangi and Carter, 2007;Ogunkoya et al, 2006;Stone et al, 2003). One possibility may be that, due to an inefficient metabolism of glucose in some fish species (Krogdahl et al, 2005;NRC, 2011), supplementation of carbohydrases may trigger metabolic stress and adverse effects in growth despite improving digestibility of other nutrients.…”

“…These results suggest that exogenous enzyme supplementation can promote the secretion of endogenous enzymes by the fish. Dalsgaard et al (2012) did an additional study with rainbow trout in which independent diets with high inclusion levels of three different plant-based feedstuffs (soybean [344 g kg −1 ], sunflower [246 g kg −1 ] and rapeseed [264 g kg −1 ]) meals were supplemented with three different enzymes (β-glucanase [67 mg kg − 1 ], xylanase [208 mg kg −1 ] and protease [228 mg kg −1 ]) and apparent nutrient digestibility was assessed. Enzyme supplementation had only moderate effects on apparent nutrient digestibility in the sunflower and rapeseed experiments, while β-glucanase and protease improved the apparent digestibility of all nutrients in the soybean experiment.…”