Growth performance and feed utilization of Asian seabass (Lates calcalifer) fed with diets containing different levels of dried housefly (Musca domestica) larvae meal

The study was conducted to examine utilization of dried housefly larvae (DFL) meal as an alternative protein source in Asian seabass diet, for effects on growth and nutrient utilization. The housefly larvae were raised in substrates composed of rice bran, discarded vegetables and fruits, molasses, and water, in a practical tropical environment. The obtained fly larvae were washed, dried, ground and analyzed for proximate composition. Four diets were formulated with DFL at 0, 6.78, 13.56 and 20.35 % of diet (with fish meal at 15, 10, 5, 0%, respectively). The diets were fed to triplicate groups of each treatment twice daily for 50 days. The DFL incorporated diets (replacing up to the 15% total of FM) had no negative effects on growth performance and nutrient utilization (p>0.05). Although statistically insignificant, the highest feed intake, final weight, and specific growth rate (SGR), namely 25.80±1.04 (g/fish), 20.55±2.67 (g/fish) and 5.2±0.25 (%/day), respectively, were all in the 13.56% DFL feeding group. The total FM replacement group (DFL at 20.35% of diet) had the lowest protein efficiency ratio (PER) of 1.55±0.06 (p>0.05). Polynomial regression of percentage weight gain revealed that DFL substitution at 8% resulted in the highest growth performance, which would potentially lower the cost per unit of diet for Asian seabass by 8.28%.