Effects of Stocking Density on Growth, Body Composition, Digestive Enzyme Levels and Blood Biochemical Parameters of Anguilla marmorata in a Recirculating Aquaculture System

Özet

We conducted a 71-day experiment to investigate the effects of stocking density in a recirculating aquaculture system(RAS) on the growth performance, body composition, digestive activity, and blood biochemical parameters of the marbled eelAnguilla marmorata. We stocked marbled eel in 1.0 m3 tanks at stocking densities of 12, 20, and 28 kg/m3, which weredesignated the low-density (LD), medium-density (MD) and high-density (HD) groups. The fish weighed 169.72 ± 2.75 g atthe baseline level. Results revealed that the fish in the LD and MD groups had a higher ash content than fish in the HD group.The crude lipid content was significantly lower in the MD and HD groups than in the LD group. The protease activities in thestomach and intestine did not differ among the three groups. The total protein and aspartate aminotransferase levels werehigher in the LD group than in the MD group. The alanine aminotransferase level was significantly lower in the LD group.These results indicate that a greater increase resulted in stress and significantly affected the growth of the fish. The optimumstocking density of A. marmorata can be achieved at 20.0 kg/m3 in a RAS.