Effect of Phytase Supplementation on Growth Performance and Nutrient Digestibility of Labeo rohita Fingerlings Fed on Corn Gluten Meal-based Diets

Alarmingly increasing cost and reduced supply of fish meal has necessitated searching out the low cost and easily accessible alternatives for aqua-feed industry. Potential of corn gluten meal (30%) and oilseed by-product, was evaluated by comparing the corn gluten meal-based diet with a fish meal-based reference diet. The experimental diet was consisted of 70% reference diet and 30% corn gluten meal contents. The potential of corn gluten meal-based diet was enhanced with graded levels of microbial phytase enzyme to assess the dose required for optimal fish production through various growth and digestibility coefficients. The chromic oxide was included at a concentration of 1% as non-digestible marker in the feed. The fish in experimental diets performed equal or better than the reference diet. The results of the study showed that the maximum weight gain (4.68 +/- 0.017 g) in fish was observed on corn gluten meal (30%)-based test diet containing 750 FTU kg(-1) level. Crude fat and apparent gross energy digestibility performed their best at 750 FTU kg(-1) followed by 1000 FTU kg(-1) level, while maximum crude protein digestibility was observed at 1000 FTU kg(-1) level. The conclusion of the present study suggested that phytase supplementation to corn gluten meal (30%) based diets at 750 FTU kg(-1) level, is enough to release sufficient bounded nutrients for optimal growth performance of Labeo rohita fingerlings. (C) 2011 Friends Science Publishers