Effects Of Stocking Density On Growth And Blood Physiology And Biochemistry In Large-sized Juvenile Russian Sturgeon

To evaluate the influence of stocking density on the growth performance, muscle composition and blood biochemical parameters of juvenile Russian sturgeon, Russian sturgeons (Acipenser gueldenstaedtii) were fed under 3 different stocking densities with 6.7kg/m3 (low),9.8kg/m3 (medium) and 13.1kg/m (high).The initial average weight of Russian sturgeonfishfor256.52±2.86g/tail.After 90 days’culture, the results are shown as follows.1. The results showed that the Russian sturgeon growth index is obviously influenced by density stress. Final body weight was significantly decreased with the increase of the density (P<0.05).There were decreased in daily weight gain, special growth rate and condition factor of the juveniles with increasing stocking density.The highest daily weight gain was seen in the low density group, whereas the lowest one was seen in the high density group.with significant difference(P<0.05).Feeding rate, weight gain and feed conversion rate increases along with the density increases.Feeding rate and net weight change obviously (P<0.05).The water temperature and pH is not significant difference. The results showed that different stocking density didn’t cause significant effect on the survival rate of the juveniles.2. This experiment also explored the effect of breeding density on the blood index of the juveniles.The content of hemoglobin and white blood cells increases along with the density increases.there were decreased in red blood cell of the juveniles with increasing stocking density.The Russian sturgeon serum inorganic ions have no obvious changes in the density of stress.Compared with the start of the experiment, during the test of cortisol remained at a low level.3.Total cholesterol and triglyceride levels were also affected by the density.Total cholesterol varied significantly among them (P<0.05).Serum total protein decreased significantly with the increase of density (P<0.05). The content of Blood glucose increases along with the density increases. The Russian sturgeon under high density stress when the first use of glucose, followed by serum protein, and finally the blood lipid.There were decreased in crude protein and crude lipid of the juveniles with increasing stocking density.The crude protein content decreases with the growth of fish body during the test, while the fat content is on the contrary. The ash content increased with the increase of stocking density,and also increased with culture time growth.The test results show that the most suitable for the actual production is the medium density group(9.8kg/m).The Low density group(6.7kg/m3) was the highest growth efficiency, but the Production of fish is too low, not suitable for the actual production operation.And high stocking density (13.1 kg/m) is not conducive to the health of fish body and cause feed waste, increase the cost of breeding.