滇池金线鲃、西畴金线鲃及其杂交F1代抵抗小瓜虫与车轮虫能力的探究

用小瓜虫(Ichthyophthirius multifiliis)和车轮虫(Trichodina spp.)对滇池金线鲃(Sinocyclocheilus grahami)和西畴金线鲃(S.xichouensis)及其杂交F1代分别进行了两次人工感染实验。18月龄的杂交F1代、滇池金线鲃(Sinocyclocheilus grahami)和西畴金线鲃(S.xichouensis)感染小瓜虫后平均死亡率分别为(50.00±11)%、(56.70±23)%、(80.0±18)%。经方差检验杂交F1代死亡率显著低于父本西畴金线鲃。6月龄杂交F1代、滇池金线鲃、西畴金线鲃感染车轮虫后的平均死亡率分别为(40.56±13)%、(56.11±5)%、(42.78±13)%。经方差检验杂交F1代死亡率显著低于母本滇池金线鲃。在感染小瓜虫和车轮虫后,三种鱼的死亡量均呈现激增后又显著回落的趋势,死亡高峰在第4天至第7天。本次感染实验的小瓜虫和车轮虫主要分布于病鱼体表:躯干分布最多57%~79%,其次为鳍12%~28%,头部分布较少4%~15%。与本研究中车轮虫几乎于鳃丝无分布(0%~3%)不同,有大约10%~20%的小瓜虫分布于鳃丝上。

Resistibility of Sinocyclocheilus grahami,S.xichouensis and their hybrid F1 to Ichthyophthirius multifiliis and Trichodina spp

Sinocyclocheilus grahami, S.xichouensis and their hybrid F1 (S.grahami ♀ ×S.xichouensis ♂) were infected twice by Ichthyophthirius multifiliis and Trichodina spp.artificially to conduct a investigation of their resistibility .The mean mortality rate of one and half a year ′s hybrid F1, S.grahami and S.xichouensis which infected by I.multifiliis was (50.00 ±11)%, (56.70 ±23)%, (80.0 ±18)% respectively.The mortality rate of hybrid F1 was significantly lower than that of S.xichouensis by analysis of variance (P <0.05), it showed that the resistibility of hybrid F1 was obviously higher than its male parent.The mean mortality rate of half of a year ′s hybrid F1, S.grahami and S.xichouensis which in-fected by Trichodina spp.was (40.56 ±13)%, (56.11 ±05)%, (42.78 ±13)% respectively.As a result of analysis of variance, mortality rate of hybrid F1 was significantly lower than that of S.grahami , it showed that resistibility of hybrid F1 was higher than its female parent apparently .Hybrid F1, S.grahami and S.xichouensis showed the similar tendency in mortality, it rose significantly in the first 3 days and reached the top during the 4th to 7th day, and then had a gradual fall, finally it dropped to 0.Trichodina spp.which was used to infect fish in this experiment appear mainly on skin of body sur -face: there are about 57% ~79% on trunk, 12% ~28% on fins and fewer on head 4% ~15%.There are 10% ~20%I.multifiliis which was found on gills, different with I.multifiliis there are rarely Trichodina spp.be found on gills in this research 0% ~3%.