Effects of Commercial Diets on Growth Performances of Juvenile Hybrid Grouper (Epinephelus lanceolatus ♂ x E. fuscoguttatus ♀) Reared Under Intensive Culture Conditions

Feed performance of hybrid grouper (Epinephelus lanceolatus ♂ x E. fuscoguttatus ♀) at 27.76±0.78 grams were evaluated. Fish were fed one control diet and three commercial diets for a duration of 42 days with 14-day sampling intervals. Experiment was performed in triplicates with 240 fish per treatment. Fish were stocked in 400-liter flow through tank with 2000% exchange of unfiltered seawater. Control treatment received previously frozen bait fish, Decapterus russelli. The three commercial diets have varying proximate compositions and price points and were obtained from three commercial fish feed producers. CD1 diet was imported from Japan at $2.7/kg with 50.8% crude protein and 10.52% crude lipid. CD2 diet was produced locally at $4.38/kg and has 45.76% crude protein and 10.2% crude lipid. CD3 diet was also produced locally at $2.03/kg and has 52.26% crude protein and 10.87% crude lipid. CD1 and CD3 treatments did not show significant differences in performance for all parameters. The control treatment had significantly higher average final weight, average weight gain, average biomass gain, ADG, SGR, GEI and MDI. However, FE and GPI were significantly lower in comparison to the other three diets. The FCR for the control treatments was significantly higher than CD1 and CD3 treatments but is significantly lower than CD2 treatments. The PER of the control treatments is significantly lower than CD1 and CD3 treatments, and there is no significant difference from CD2 treatments. CD2-fed fish had significantly lower average final weight, average weight gain, average biomass gain, ADG, and SGR in comparison to the other three diets. CD2 treatments had significantly higher FCR and mortality than all other treatments. There were no significant differences in survival between the three other treatments. The CD3 diet yielded the best growth and health performances in relation to its price. However, high degrees of standard deviation in multiple parameters could mean an inconsistent quality that may have long term negative effects. Of the three commercial diets, CD1 gave the best overall performance. Further investigation over the entire grow out cycle will be required to determine the full potential and pitfalls of CD1 and CD3 diets