The aim of this study was to evaluate the effect of diets containing two protein sources (plant and animal) and different levels of an enzymatic complex (0, 50 and 75g/ton) in the zootechnical performance of Nile tilapia Oreochromis niloticus juveniles. The experimental design was completely randomized in a 2x3 factorial scheme with four replications.
The enzyme complex consists of a combination of amylase, xylanase, beta glucanase, beta mannanase and protease. All diets were isoprotein (32% CP) and isoenergetic (4100 kcal GE/kg). Fish meal were used as a animal protein source, and soybean meal was the main ingredient in the plant based diet. Nile tilapia juveniles (approximately 5,25±0,22 of initial weight) were distributed in 24 tanks (70 L) at a density of ten fish per tank. The tanks were connected to a recirculation system equipped with heating and aeration. After 90 days of the experiment the zootechnical performance was evaluated.
No interaction (P>0.05) was found between the factors for any evaluated parameter. Regarding the source of protein, diets containing animal protein improved (P<0.05) the growth, feed ingestion and feed efficiency compared evaluated when compared to plant based diets. The higher inclusion of the enzymatic complex increased (P<0.05) the growth and feed ingestion, Survival was not affected(P>0.05) by the treatments.
From the results it can be concluded that the protein sources affects the zootecnical performance of Nile tilapia juveniles. Supplementation with enzymatic complex improved growth and feed intake. The weight gain response was proportional to the level of enzyme supplementation.