| Silurus asotus,belonging to Siluridae and Silurus,is widely distributed in all tributaries of China except xinjiang and qinghai-tibet plateau.Like some other fish,Silurus asotus show marked sex differences in both natural and farmed conditions.In order to find out the difference between the two sexes of Silurus asotus,the paper carried out the research on "the morphology,blood physiology and biochemistry of individual Silurus asotus and their GH/IGF growth axis gene",in order to provide reference materials for the scientific breeding of Silurus asotus.In the experiment,the morphological and blood physiological and biochemical indexes of Silurus asotus were determined by distinguishing the male from the female in summer,autumn and winter,and the expression of growth-related genes in various tissues was detected by q-PCR technology.The results are as follows:(1)In summer,autumn and winter,the body length and weight of female were significantly greater than that of male.Compared with the three seasons of summer,autumn and winter,the differentiation trend of body length between male and female groups was more and more obvious.Except for the two variables of eye diameter and the distance between the anal and pelvic fins,there were no significant differences between the male and female groups in summer,and the other variables showed significant(P<0.05)or extremely significant(P<0.01)differences in the growth process.The analysis of the static allometric growth of the 14 morphological indexes relative to body weight found that the morphological growth patterns of female and male were different in different seasons,and the body length of female in different seasons was faster than that of body weight.(2)In summer,the body weight,visceral weight,empty shell weight and intestinal weight of female were significantly greater than those of male(P<0.05),and the other variables were not significantly different between female and male.In autumn and winter,there were significant differences in body weight,visceral weight,empty shell weight,gonad weight,intestinal weight,kidney weight and spleen weight between female and male,and the female was larger than the male.From summer to winter,the abundance of Silurus asotus decreased.The maturation coefficient of female Silurus asotus showed an upward trend,and was basically stable in winter.The maturation coefficient of male was basically unchanged.(3)In summer,there were significant differences in RBC volume,hemoglobin content and RBC number between female and male(P<0.05),and the number of male was greater than that of female.There was no difference in other blood parameters between female and male Silurus asotus in different seasons.Season and gender for each indicator to two-factor variance analysis(Tow-way ANOVA)showed that red blood cells deposited,hemoglobin content,white blood cell count,cereal third transaminase,aspertate aminotransferase,blood glucose,lactate dehydrogenase and triglyceride were significant(P < 0.05)or very significant(P < 0.01)gender differences,time,and gender interaction effects on the indexes were not significant.(4)GH,GHR2 and IGF1 genes were widely expressed in the tested tissues before and after feeding.GH gene was significantly expressed in the pituitary,followed by gonad,liver and hypothalamus.The expression level of GH gene in the gonad was significantly higher in male fish than in female fish(P<0.05),and the expression level in the pituitary was enhanced after feeding and the female was higher than the male.GHR2 gene expression in the gonad quantity highest,followed by liver,pituitary,after feeding expression level organizations are changed,the male enhanced expression of hypothalamus,female is abate,and significant differences between the sexes(P<0.05),male and female expression of pituitary were enhanced,the male expression of gonad is abate,the male express no significant changes in liver;IGF1 gene was mainly expressed in pituitary gland and gonad before feeding,but was relatively low in hypothalamus and liver.After feeding,the expression level in hypothalamus and gonad was basically unchanged,the expression level in liver was enhanced,and the expression level in gonad was decreased. |
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