Currently, plant ingredients such as soybean meal and canola meal are commonly used feed ingredients in aqua feed industry. These ingredients contain high amount of anti-nutritional factors (ANFs) such a s non-starch polysaccharide ( NSP) and phyt ic acid. ANFs have significant effects on fish gut morphology, physiology, and mucus layer which influence the endogenous secretion of water, proteins, electrolytes, and lipids leads to reduce the nutrient and energy digestibility. Exogenous supplementation of enzymes can be used to overcome the problems , resulting in improved rate of digestion and nutrient absorption of plant protein in aquatic animals. Exogenous xylanase has the property of disrupting the plant cell wall integrity, thereby reducing the molecular size characteristics of NSPs. Consequently, this enhances rapid digestion by reducing the viscosity in the gut. Hence, the objective of this study was to evaluate the effects of dose dependent of xyla nase supplementation on growth, apparent digestibility, and digestive enzymes activities in Nile tilapia diet.
Plant based four diets (isonitrogenous 35% crude protein and isolipidic 8% lipid) viz control diet and three different levels (16000, 32000 and 6400 BXU/kg) of three xylanase (Econase XT) supplemented in control diet. Diets fed in triplicate to tilapia juveniles ( 1452 fish, 126 ± 0.04 g initial weight) for 11 weeks. Fish were randomly distributed into 12 400-L tanks in recirculatory aquaculture system.
At the end of the feeding trial , supplementation of xylanase had significant effect of growth performance and feed utilization (Figure 1). Highest growth performance and protein efficiency ratio were observed in a group fed with diet 2 (16, 000 BXU/kg) which was significantly similar to group 3 (32000 BXU/kg) whereas feed conversion ratio exhibited opposite trend. Hepatic histological changes were affected by dietary treatment. Data for nutrient retention and digestibility coefficient of nutrient and energy will be presented. Conclusively, dietary supplementation of xylanase (Econase XT) in the range of 16,000 – 32,000 BXU per kg is recommended for improving the plant protein utilization in Nile tilapia for sustainable aquaculture production.