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）...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.展开更多
Ponyfishes of the family Leiognathidae frequently show overlapping distribution pattems in the Indo-Pacific and South China Sea. The mouth morphology of three species of ponyfishes which feed at different lerels in th...Ponyfishes of the family Leiognathidae frequently show overlapping distribution pattems in the Indo-Pacific and South China Sea. The mouth morphology of three species of ponyfishes which feed at different lerels in the water column were compared. The species could be distinguished primarily by the mouth meropology. Gazza minuta (Bloch)feeds mainly on bethos, has the least protruding jaws; Secutor ruconius (Hamilton-Buchanan) feeds mainly on plankton, has the most protruding jaws, Leiognathus rivuatus (Temmink et Schlegel) has an intermediate deggree of jaw protrusion. This study showed that closely related species with overlapping distributions frequently exhibit morphologlcal, phpsiological or ecological differences related to the search for food, the intake of food or locomotion mode.展开更多
文摘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.
文摘Ponyfishes of the family Leiognathidae frequently show overlapping distribution pattems in the Indo-Pacific and South China Sea. The mouth morphology of three species of ponyfishes which feed at different lerels in the water column were compared. The species could be distinguished primarily by the mouth meropology. Gazza minuta (Bloch)feeds mainly on bethos, has the least protruding jaws; Secutor ruconius (Hamilton-Buchanan) feeds mainly on plankton, has the most protruding jaws, Leiognathus rivuatus (Temmink et Schlegel) has an intermediate deggree of jaw protrusion. This study showed that closely related species with overlapping distributions frequently exhibit morphologlcal, phpsiological or ecological differences related to the search for food, the intake of food or locomotion mode.
