病原感染条件下中国对虾二倍体和三倍体血液学变化

以热休克诱导获得中国对虾三倍体，通过口服或注射的方式对二倍体和三倍体中国对虾进行了白斑综合征病毒(WSSV)和鳗弧菌感染实验，研究了病原感染前后二倍体和三倍体中国对虾血液学的变化并首次报道了三倍体中国对虾血细胞的组成。实验结果表明：三倍体和二倍体中国对虾均对WSSV敏感，三倍体未显示出明显的抗性。WSSV感染4d后，对虾外周循环系统的血细胞数量明显减少，三倍体和二倍体对虾血细胞数量均降为对照组的10％左右。对虾血细胞组成发生变化，大颗粒细胞明显减少，小颗粒细胞相应增加，而透明细胞所占比例基本不变；大颗粒细胞和小颗粒细胞内颗粒物质均有所减少，出现空泡或细胞外突起等异常结构。注射鳗弧菌感染后两种对虾的血细胞数量均有所减少，血细胞数量的减少与弧菌的注射量呈正相关关系：三倍体中国对虾血细胞组成与二倍体相似，但其密度仅为二倍体的40％左右：本研究结果为三倍体对虾抗逆特性的研究提供了一定依据和参考。

Haematological changes of sibling diploid and triploid Fenneropenaeus chinensis after being challenged with pathogens

Based on polyploid induction method in shrimp established in our laboratory , triploid Chinese shrimp, Fenneropenaeus chinensis was induced by heat shock to inhibit meiosis ? . Triploid shrimps and their diploid siblings were challenged w ith white spot syndrome virus (WSSV) through oral administration or with Vibrio anguillarum by injection. Shrimps without pathogens challenge were used as controls. Hemocyte count and composition in hemolymph of diploid and triploid shrimp were compared. This is the first time to report the cell count and composition of hemolymph in triploid shrimp. It showed that pathogens challenge resulted in obvious haematological changes. A signif icant decline for hemocyte count in both diploid and triploid shrimp af ter 4 days challenge was observed. Hemocyte count of both diploid and triploid shrimp was reduced to about 10% of that of control. The composition of hemocytes either in diploid or triploid shrimp changed after WSSV challenge. The  amount of large granule cells ( LGC) decreased, while that of small granule cells ( SGC) increased. However, the amount of hyaline cells (HC) remained unchanged. Some abnormal structures such as vacant vacuoles were found in SGC and LGC of the infected shrimp. Hemocyte count of diploid and triploid shrimp decreased too after being infected with Vibrio anguillarum, and the range of decline was positively related with the injection dosage of Vibrio anguillarum. Triploid shrimp has larger hemocyte volume and lesser total hemocyte counts, which accounts for about 40% of that of diploid, but the hemocyte composition in triploid was the same as that in diploid. Results above provide basis and reference for stress resistance research on triploid shrimp.