Exogenous enzymes are widely applied in feed for monogastric animals including pigs and poultry as a means to increase the nutritional value of viscous grains by reducing the anti-nutritional effects of primarily non-starch polysaccharides (NSPs). In comparison, there is very limited information on the effects of enzymes in fish feed apart from phytase. Phytase works by hydrolyzing phytic acid, and numerous studies have documented that phytase supplementation increases phosphorus availability in fish fed diets with high inclusion levels of plant proteins. Plant derived proteins are increasingly used in fish feed due to growing demands for and high price variations in fish meal, but high inclusion levels in diets for carnivorous fish are hampered by a great variety of anti-nutritional factors (ANFs), which reduce nutrient utilisation. Exogenous dietary enzymes may potentially help to alleviate these effects, and the objective of the present study was to evaluate the effects of supplementing protease and pectinase to a diet containing approximately 30% soybean meal, rapeseed meal or sunflower meal on nutrient digestibility in juvenile rainbow trout (Oncorhynchus mykiss). Digestibility trials were carried out using a modified Guelph set-up. Rainbow trout were fed the un-supplemented diets and enzyme supplemented plant-based diets in triplicates for three weeks. While moderate effects of the enzymes on nutrient digestibility were obtained with sunflower and rapeseed meal based diets, both enzymes significantly increased (P <0.05) the apparent digestibility coefficients (ADCs) of protein, lipid and nitrogen-free extract (NFE) in soybean meal based diets. Hence, the study provided preliminary results on the potential of protease and pectinase to increase the nutritional value of proteinaceous feed ingredients for fish. However, it also reinforces the complexity of using exogenous dietary enzymes and that more research is required to better understand the mechanisms of actions.
|Title of host publication||Books of Abstracts|
|Publication status||Published - 2010|
|Event||14th International Symposium on Fish Nutrition & Feeding - Qingdao, China|
Duration: 31 May 2010 → 4 Jun 2010
Conference number: 14
|Conference||14th International Symposium on Fish Nutrition & Feeding|
|Period||31/05/2010 → 04/06/2010|