蚯蚓与蝇蛆对中国对虾生长及抗白斑综合征病毒感染的研究

以中国对虾（Fenneropenaeus chinensis）为实验材料，分别投喂配合饲料、蚯蚓、蛤蜊、蝇蛆等四种饵料，利用生长和抗病性指标综合评价蚯蚓和蝇蛆作为中国对虾饵料的可行性。生长实验前测定每个实验组的初始体长和体重，养殖40d后再次测定生长指标，之后，分别投喂不同毒饵量进行人工感染实验。方差分析表明：投喂四种饵料后，蛤蜊组生长最快，其次是蚯蚓，再次是蝇蛆，最后是配合饲料，各组之间对虾体长增长差异显著（P<0.05），体重增长差异极显著(P<0.01) 。利用线性固定模型分析不同饵料及不同病毒量感染下对中国对虾存活率的影响，其中蚯蚓组存活率最高，配合饲料组存活率最低，并且蚯蚓组存活率显著高于蛤蜊组和配合饲料组(P<0.05)，蝇蛆组显著高于配合饲料组（P<0.05）。研究结果表明：蚯蚓和蝇蛆可显著提高中国对虾的生长速度，明显提高中国对虾的抗病性，是很好的对虾饵料。

Effects of earthworm and housefly larva on growth and white spot syndrome virus arti-infection of Fenneropenaeus chinensis

Chinese shrimp (Fenneropenaeus chinensis) is one of the leading cultured species in China. But shrimp farming is currently threatened by pathogen, such as virus, bacteria, etc, among which the white spot syndrome virus (WSSV) is the most serious. The efficient method to avoid or diminish the influence of the virus may lie on the diet, as evidences have revealed the main way that the WSSV was spread in Chinese shrimp was caused by food. This study was initiated to assess the effect of earthworm and housefly larva on growth and survival rate of F. chinensis after WSSV infection. Commercial feed and calm were control groups, and earthworm and housefly larva were assigned into four treatment groups. Three repetitions were made for each diet treatment with 130 individuals in each repetition. The body length and the body weight were measured before and after the experiment, respectively. The survival rate was also calculated when the shrimp were challenged with different gradient WSSV by oral infection, and the dead shrimp were removed every two hours. The descending order of the gain of body weight and body length in the four diet treatment was clam, earthworm, housefly larva and commercial feed. There was significant difference between the body length (P<0.05) and very significant difference between the body weight of each group (P<0.01). Fixed linear model was applied to test the survival rate of F. chinensis by diet variation and different WSSV dosage. The results showed that the survival rate of F. chinensis fed on earthworm and housefly larva was significantly higher than that of the clam and commercial diet fed groups, and the survival rate of group fed on housefly larvae was significantly higher than that of group fed on artificial feed. The results indicated that earthworm and housefly larvae can obviously enhance the growth and disease resistance of Chinese shrimps, and are good food for Chinese shrimps. Results detected by Nest-PCR showed none of shrimp was infected by WSSV prior to the experiment, and the positive rate of 96.94% of shrimp mortality was possibly caused by infection.