Protease inclusion in diet for hybrid red tilapia (Oreochromis mosambicus x Oreochromis niloticus)

Abstract

An experiment was conducted to evaluate effects on growth, body composition and nutrient digestibility of addition protease to hybrid red tilapia diet for 12 weeks. Hybrid red tilapia approximately 9.0g in initial weight was stocked into 350L rearing tanks with the density of 80 individuals per tank. The commercial feed consisted of 30% crude protein, 3.5% crude lipid, 54.5% carbohydrate, 11.8% crude ash and gross energy of 18.1KJ g-1 was experimental feed. Five different concentration of protease enzyme was added at1, 2, 4, 6 and 8g.kg−1 diet and non-enzyme added was kept as control diet. The results showed there was no significant difference in DWG and SGR between treatments (p>0.05). Increasing in level of protease enzyme in the diet resulted in decreasing of FCR. The significant lower (P<0.05) FCR (from 0.97 to 1.02) was found in the diets with high levels of enzyme supplementation (4, 6, 8 g.kg-1) compared to those (from 1.10 to 1.15) in the diets with low levels of enzyme addition (1, 2 g.kg-1) and control treatment. Moreover, protein efficiency ratio (PER) showed the similar trend with the FCR. The highest ADC of feed in dry matter, ADC protein, ADC lipid and ADC energy were found in treatments fed diet containing 4 g.kg-1 of enzyme. In conclusion, addition of the protease enzyme in diets for red tilapia did not affect to survival rate, fish proximate composite, but can decreased FCR and enhanced fish digestibility in term of protein and energy, feed utilization.