Enzyme Supplementation To Soybean Based Diet in Gilthead Sea Bream (Sparus Aurata): Effects on Growth Parameters and Nitrogen and Phosphorus Excretion

Abstract

The aim of the present study was to examine the effects of the diets based on soybean meal supplemented with exogenous enzymes on growth performance, feed utilization, apparent digestibility and waste output of nitrogen and phosphorus in gilthead sea bream (Sparus aurata) culture. Diets consisted of 40% fish meal (FM) and 25% dehulled hexane extracted soybean meal (SBM) in commercial feed (TM) and 25% fish meal (FM) and 40% dehulled hexane extracted soybean meal (SBM) in control group (CO), and diet supplemented with enzyme 1 (PRT= Protease; 2 g/kg(-1)), diet supplemented with enzyme 2 (MIX; cellulose, xylanase, endo-beta-1,3: 1,4-glucanase; 2 g/kg(-1)) and diet supplemented with enzyme 3 (PHY: Pyhtase; 2 g/kg(-1)). A stocking design at 55 fish each tank, gilthead sea bream (initial weights 89.50 +/- 1.5 were randomly total of 825 fish allocated into 15 tanks and fed five experimental diets. While weight gain (125.00-133.50) and specific growth rate (0.42-0.50) were statistically similar (P>0.05), feed efficiency ratio (2.52-2.90) and condition factor (1.85-2.08) significantly different among groups (P<0.05) at the end of the experiment. Addition of PRT and PHY into control significantly improved specific growth rate, feed efficiency ratio and condition factor. In this study, showed the highest nitrogen apparent digestibility coefficient (83.20 +/- 1.98) in group of PRT whilst the poorest value obtained (69.72 +/- 0.01) group of CO. The best (58.57 +/- 0.49) and the lowest (42.85 +/- 1.98) ADC for phosphorus were obtained from PHT and CO, respectively (p<0.05). In conclusion, this study has shown that dietary different enzyme supplementation can have a positive effect on growth, feed utilization and digestibility in gilthead sea bream. This positive effect has been not only alleviate the negative effect of replacing dietary FM with SBM but also provide about better performance compared to fish fed a higher FM containing diet.