| Takifugu obscuurs and Takifugu rubripes belong to Takifugu, both of them are important econimic fishes in China. But the method of large-scale family construction of Takifugu obscurus hasn’t established yet. also as an important factor influencing the early stage of family construction, the quality of Takifugu obscurus and Takifugu rubripes eggs still havn’t have evaluation criteria. To establish the method of large-scale family construction, to investigate the relationship between the developmental capacity and biochemical parameters of egg in Takifugu obscuurs, also to investigate the variation of physiological and biochemical parameters in the over-ripening eggs of Takifugu rubripes and the effect on egg quality, Three parts of experiment were studied in this paper, the details are as follows:1. Family construction and early standardized cultivation of Takifugu obscurusWith the technologies of artificial fertilization and family construction, To carry out a family selective breeding for Takifugu rubripes, full-sib families were constracted and technology of standardized cultivation was used. Three Takifugu rubripes populations, including Guangzhou, Jiangsu and Shanghai populations were used for artificial fertilization in ratio of one female to one male. At the early breeding stage of Takifugu rubripes, the environment was standardized and the first, second, third and fourth quantity standardization were demanded. Results show that most of the parental fish had large amounts of eggs, the majority of egg laying amount per female were between 250-350g, only five families’fecundities were under 200g and were eliminated. The number of newly hatched larvae in families fluctuated and were varied from five thousand to one hundred and forty thousand. There were six families which number of newly hatched larvae were under fifty thousand were eliminated. It was found that from four times quantity standardization, after the first level of quantity standardization, there were sixty-six families which survival rates were above 80%. and only one families’ survival rate was under 50% and was eliminated. After the second level of quantity standardization, most of the families’ survival rates were above 70%, there were only three families were eliminated for which survival rates were under 70%. After the third level of quantity standardization, the survival rates of all the families were above 70%, and there only two families’ survival rates were not more than 80% and were eliminated. After the forth level of quantity standardization, all the families’ survival rates were above 80%, and there were forty-two families which survival rates were above 90%. It could be seen that the survival rate of the majority of families were high. After four times quantity standardization,82 full-sib families were constructed successfully. The results demonstrated that large fecundity was benefit to the construction of full-sib family, also enough number of brood stocks were necessary for artificial fertilization and family construction. Also at the early stage of family construction and breeding, keep synchronization of families can reduce the impact of environmental differences among families.Solutions were discussed on problems of family construction, with which reference was offered to large-scale family construction of Takifugu rubripes.2. Analysis of phosphatase and other biochemical parameters of egg and its quality determination in Takifugu obscurusThe basic components, phosphatase activity, malate dehydrogenase activity, sialic acid, amino acid content in unfertilized eggs of Takifugu obscurus were measured by means of biochemical analysis, also fatty acids composition were measured by means of GC-MS, and the correlation with components and hatching rates were analysed. Results of experiments showed that activity of acid phosphatase, sialic acid content and the hatching rate were significantly correlated (P<0.05, Ri2=0.501, R22=0.406), alkaline phosphatase and hatching rate were significantly negative correlation (P<0.05, R2=0.690). C14:0 and hatching rate were significantly negative correlation(P<0.05, R2=0.684), and showed a decline trend. ARA, DHA and hatching rates were significantly correlated (P<0.05, R12=0.447, R22=0.710), and both of them showed a tendency of first increasing and then decreasing with the hatching rate. The content of n-3 fatty and the ratio of DHA and EPA and the ratio of EPA and ARA all had significant correlation with the hatching rate(P<0.05, R12=0.509, R22=0.722, R32=0.550). The results demonstrated that phosphatase, sialic acid, fatty acid and egg hatching rate have correlation, also when the activity of ACP were in the range of [68.045,141.038], when the activity of AKP were in the range of [2.298, 7.241], when the content of SA were in the range of [9.081,19.973], when the content of C 14:0 were in the range of [0.485,0.658], when the content of ARA were in the range of [1.371,2.498], when the content of DHA were in the range of [13.838,18.469], all of them could be the references of which hatching rates were no less than 50%. Accordingly these references could reflect the developing value of Takifugu obscurus’egg in breeding production, which could also be used as reference index for embryo and objective evaluation of the quality of its egg.3. Physiological and biochemical parameters characterizing Takifugu rubripes egg and its quality evaluationThe spawning of mature broodstocks were put off one and two weeks, the variations of phosphatase, malate dehydrogenase, fatty acids and other biochemical parameters of egg were analysed, also the correlation were analysed and compared with normal group. Results of experiments show that put off one week, fertilization rate in group B dropped significantly(P<0.05).After two week, fertilization rate of C group dropped to 31.89%. With the delay of spawning, activity of acid phosphatase dropped significantly(P<0.05) and had a significant correlation. In normal group A, the activity of malate dehydrogenase was significantly higher than B and C(P<0.05). Amino acid content had the same variation tendency, in A and B group amino acid content were higher than C group(P<0.05). The ratio of C14.0, C15:0, C16:0, C16:1n-7, C18:3n-3, C20:5n-3 in total fat were highest in normal group, and had positive correlation with fertilization rate significantly(P<0.05). C22:5n-3, DHA:EPA had negative correlation with fertilization rate significantly. The results demonstrated that acid phosphatase, malate dehydrogenase, amino acid and fatty acids can reflect the over-ripening of Takifugu rubripes egg, which can also be used as a reference index for evaluation of its egg quality. |
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