放养密度对大杂交鲟大规格鱼种血液生理生化指标的影响

Effect of Stocking Density on Bloodphysilogy and Serum Biochemistry Indicators in Hybrid Sturgeon

以大杂交鲟大规格鱼种(达氏鳇♀×史氏鲟含,初始体重约243g/尾)为实验材料,研究在6、9、12和15kg/m^34个放养密度条件下,饲养70d后,其血液生理生化指标的变化情况。结果表明,高密度产生的拥挤胁迫能引起大杂交鲟鱼种血液生理指标和主要生化指标发生明显的改变。随着放养密度的升高,血红蛋白浓度升高,白细胞数目、淋巴细胞数目、中性粒细胞数目、血栓细胞数量增加,说明鱼体自身处于免疫应激状态;红细胞数目在最高密度条件下降低,说明呼吸能力在高密度养殖备件下受到抑制;鱼体内血清中总蛋白、尿酸和尿素浓度随着放养密度增大显著升高(P<0.05),葡萄糖、甘油三酯、总胆固醇浓度随密度增大而降低(P<0.05),表明高密度养殖对大杂交鲟血液和体内消化酶活力具有一定负面影响;鱼体内血清中的谷丙转移酶、碱性磷酸酶、天门冬氨酸氨基转移酶三种酶活性也随着放养密度增大而显著增大(P<0.05),而总胆红素浓度随着放养密度的增大而显著降低(P<0.05),这均表明过高放养密度下鱼体肝脏组织受到一定损伤。本文研究结果显示该规格下大杂交鲟的适宜放养密度不超过12kg/m^3,否则对鱼类血液生理和血清生化组份均产生不良影响。

The experiment was performed on the large-size hybrid sturgeon（Huso dauricus♀ × Acipenser schrenckii ♂ , with an initial weight of 243g per fish）under the stocking density of 6 kg/ma , 9 kg/ma ,12 kg/ma and 15 kg/ma over a 70d period. The variation of blood biochemical composition, hemocyteand other physiological indexes indicated that crowding stress resulted in significant change of bloodphysiological indexes and biochemical composition. Concentration enrichment of HGB was caused by in-creasing stocking density. What＇ s more, increasing number of WBC, Lymph, Gran and PET showedthat the fish were in a state of immune stress. Decreasing of RBC due to the highest stocking density in-dicated that breathing capacity was inhibited by high density condition. Plasma content of TP, TG, UAand UREA rose significantly （P 〈 0. 05） following the increase of stocking density. High densityshowed negative effect on blood and digestive enzymes vitality in hybrid sturgeon body, which was con-cluded from the decreased concentrations of Glu, TG, TC（P〈0.05）. In addition, significant vitalityenhancement （P〈0.05） of blood serum ALT, ALP as well as AST, and significantly declined concen-tration（P〈0.05） of T-Bil indicated that liver tissue of fish was damaged by a rather high density. Theresults proved that the proper stocking density of this specification of fish should be less than 12kg/m^3 ,otherwise there was a negative effect on blood physiology and serum biochemical composition.