摘要
This study was conducted to study the effects of a commercial exogenous digestive enzymes （EDE） containing cellulases, xylanases, u-amylase and proteases from anaerobic bacterium and natural enhancer mixture （NEM） containing allicin, high unit hydrolytic enzyme, Bacillus subtilis spores and ginseng extracts on survival, growth, carcass composition and feed cost/benefit in rabbitfish, Siganus rivulatus. Nine net cages （100 cm × 100 cm × 40 cm; L ×W ×H） were stocked with 10 juvenile rabbitfish （1.1 g per fish） each and placed in a large rectangular tank and offered feed at 4% body weight daily. Three replicates per treatment were offered three isonitrogenous and isocaloric diets, control and two supplemented diets with EDE or NEM at 2 g/kg diet for 74 days. Fish in all cages were weighed at two-week intervals and feed regimen was adjusted accordingly. Rabbitfish offered the control diet exhibited lower growth significantly （P 〈 0.05） and feed utilization than the other two experimental treatments. Experimental diet supplemented with NEM recorded the highest growth performance, feed conversion ratio, protein efficiency ratio, net protein utilization and energy retention significantly （P 〈 0.05） than the other two tested groups. Carcass composition and somatic parameters index was not affected by dietary EDE or NEM inclusion. Ultimately, when all variables are considered, EDE and NEM inclusion to diets appears to reduce feed cost per unit growth of rabbitfish.
