中华鲟血清卵黄蛋白原水平的初步观察

通过碱不稳定性蛋白结合磷法测定不同年龄中华鲟(Acipenser sinensis)血清中磷含量,以磷的含量变化反映卵黄蛋白原(VTG)变化情况。实验鱼为人工养殖0.5、1、2、3、4、5、6、8、9、10龄中华鲟和野生成熟中华鲟,共81尾,其中8尾野生雌鱼在人工繁殖前后各取样2~4次,共测97个血液样本。结果显示:低龄中华鲟VTG含量较低,最低值在5龄,含磷量为(4.6±1.6)mg/L,5龄后增加,成熟后达到最大,含磷量为(52.0±4.5)mg/L。在性腺不同发育时期,雌性个体在Ⅱ~Ⅴ期VTG的含量增加,Ⅱ~Ⅲ期增加速度较快,随后变缓,Ⅴ期达到最高水平,Ⅵ期降低;而雄性个体在Ⅱ~Ⅳ期VTG的增加量很少,Ⅳ期达到最高水平,含磷量为(28.7±12.2)mg/L。繁殖雌鱼产前VTG含量最高,含磷量为(62.5±8.7)mg/L,产后低于产前。此外,发现产后鲟鱼卵巢液中含量低于其血清中含量,但高于其他年龄组血清中的水平。本实验表明淡水养殖的中华鲟有可能达到性成熟。

Variation in the Serum Vitellogenin Levels of Chinese Sturgeon(Acipenser sinensis)

The Chinese sturgeon(Acipenser sinensis)is an anadromous fish.Sexual maturity is reached between 8～18 years in males and between 14～26 years in females.The yolk proteins of Chinese sturgeon are chief supplemental nutrition and energy for embryo development,which come from vitellogenin(VTG).The levels of plasma VTG were performed in an indirect method,by measuring the alkali-labile phosphorus content of the lipid-free protein fraction.The levels of phosphorus can reflect the VTG levels indrectly.In the experiment,the phosphorus levels in serum of Chinese sturgeon were measured by the chemic response with the aqueous trichloroacetic acid(TCA).97 serum samples from 81 fishes were measured.The fish included the cultured ones,0.5,1,2,3,4,5,6,8,9 and 10 year-old,and the wild matured ones which were caught below Gezhouba Dam in Yangtze River.The results showed that the VTG was low at the early ages from 1 to 5 years,and then increased.The matured wild sturgeons had the highest levels,52.0±4.5mg/L.From the gonadal development stage Ⅱto stage Ⅵ,the VTG levels of females were increased quickly,especially during stage Ⅱto stage Ⅲ,the highest level was at stage Ⅴ,and then descended at stage Ⅵ.However,it increased slowly in males during stageⅡto stage Ⅳ.At stage Ⅳ,the phosphorus levels at stage Ⅳ were 28.7±12.2mg/L in males.In the artificial spawning fish,the VTG level was higher in prespawning 62.5±8.7mg/L than in postspawning period.In addition,the results also showed that it was higher in the overian succus of the spawning stock than in the other ages.It was suggested that the cultured Chinese sturgeon in fresh water were likely to be matured.