| Apostichopus japonicus is a species of sea cucumber in the phylum of echinodermata,deuterostome division,which is the most similar group of invertebrates to chordate.It is also an important marine product in China,featuring high economic value.In recent years,the breeding industry of Apostichopus japonicus has gained rapid growth,but the breeding technology remains immature.Problems such as germplasm,disease,environment and product quality are becoming increasingly evident while scaling up the breeding of Apostichopus japonicus.The huge specification difference among Apostichopus japonicus coming from the same batch of breeding directly affects economic return.Existing studies had found that the external factors causing such difference are density,social scale,physical contact,etc.Other studies indicated that Apostichopus japonicus with different specifications showed varied immunity performance.But the relationship between immunity and the growth of Apostichopus japonicus remains unclear.In this experiment,the immunity of wild and cultural Apostichopus japonicus with varied specification were studied.Body mass and living environment are correlated with the immunity of Apostichopus japonicus was analyzed by comparing the differences in aspects such as density and quantity of coelomocytes,immunoenzyme activity and immunogene expression.The research results serve to provide a basis for fundamental experiment that aims to explore the immune mechanism of Apostichopus japonicus and establish the immune indexes of Apostichopus japonicus.The volume of coelomic fluid,density and quantity of coelomocytes of wild(70 g group,110 g group and 150 g group)and cultural(30 g group,70 g group and 110 g group)Apostichopus japonicus with varied specifications were compared and analyzed in the experiment.The results found that the volume of coelomic fluid in both cultural and wild Apostichopus japonicus increased with weight gain,demonstrating extremely significant difference concerning the volume of coelomic fluid in Apostichopus japonicus of varied specifications(P < 0.01);the difference between cultural and wild Apostichopus japonicus in the 70 g group was not significant(P > 0.05).The volume of coelomic fluid of the cultural Apostichopus japonicus in the 110 g group was significantly higher than that of the wild Apostichopus japonicus of the same specification(P < 0.05).There was no significant difference concerning the gross density of coelomocytes of Apostichopus japonicus with varied specifications(P > 0.05).The difference concerning gross density of coelomocytes between the cultural and wild Apostichopus japonicus in the 70 g and 110 g groups was not significant(P > 0.05).There was extremely significant difference in gross density of coelomocytes of Apostichopus japonicus with varied specifications(P < 0.01).The total number of coelomocytes of both wild and cultural Apostichopus japonicus increased with the rise of weight.The difference concerning total number of coelomocytes in both cultural and wild Apostichopus japonicus in the 70 g and 110 g groups was not significant(P > 0.05).By studying the density and quantity of different types of coelomocytes,it was found that there was no significant difference in density of different types of coelomocytes of cultural Apostichopus japonicus with varied specifications(P > 0.05),but the density of sphaerocyst in the 150 g group of wild Apostichopus japonicus was significantly higher than that in the 70 g and 110 g groups.By comparing the cultural and wild Apostichopus japonicus of the same specification,it was found that the density of both sphaerocysts and lymphocytes in the 110 g group of cultural Apostichopus japonicus was significantly higher than that of the wild Apostichopus japonicus(P < 0.05).In this experiment,the immunoenzyme activities of coelomic fluid supernatant of wild(70 g group,110 g group and 150 g group)and cultural(30 g group,70 g group and 110 g group)Apostichopus japonicus with varied specifications were compared and analyzed.The results indicated that the ACP activity of coelomic fluid supernatant of cultural and wild Apostichopus japonicus 110 g group was significantly higher than that of the other two groups(P < 0.05),and there was no significant difference between the cultural and wild Apostichopus japonicus of the same specification(P > 0.05).There showed no significant difference concerning AKP activity of coelomic fluid supernatant of cultural and wild Apostichopus japonicus in three specifications(P > 0.05),so was the case between the cultural and wild Apostichopus japonicus of the same specification(P > 0.05).The SOD activity of coelomic fluid supernatant of cultural Apostichopus japonicus 30 g group was significantly higher than that of the other two groups(P < 0.05),with no significant difference among wild Apostichopus japonicus in three specifications(P > 0.05)and between cultural and wild Apostichopus japonicus of the same specification(P > 0.05).The CAT activity of coelomic fluid supernatant of cultural Apostichopus japonicus 110 g group was significantly higher than that of the other two groups(P < 0.05),with no significant difference among wild Apostichopus japonicus in three specifications(P > 0.05)and between cultural and wild Apostichopus japonicus of the same specification(P > 0.05).Comparative analysis was performed on immune-related genes(AjNLRP3,AjC3,AjRac1,AjMKK3/6,AjTRAF3,Aj-iLys,AjAP-1,AjTLR3,AjToll)expression of coelomocytes from coelom and polian vesicle of cultural Apostichopus japonicus(30 g group,70 g group and 110 g group)with varied specifications by fluorogenic quantitative PCR technique.By comparing the expression levels of immune-related genes in coelomocytes from coelom,it was found that the expression levels of 9 genes in the 70 g group were significantly higher than those in the 110 g group;The expression levels of 6 genes of AjC3,AjRac1,AjMKK3/6,Aj-iLys,AjTLR3,and AjToll in the 30 g group were all significantly higher than those in the 110 g group;the expression levels of AjNLRP3,AjTRAF3,AjMKK3/6 and AjC3 in the 70 g group were significantly higher than those in the 30 g group,and there showed no significant difference in AjAP-1,AjTLR3,AjToll and AjRac1 between the two groups.Conclusions can be reached based on the above results that the expression level of immune-related genes was highest in coelomocytes from coelom of the cultural Apostichopus japonicus of the 70 g group,followed by the 30 g group,lowest in the 110 g group.By comparing the expression levels of 9 immune-related genes in the coelomocytes from polian vesicle,it was found that the differences between groups shared distinct rules with coelomocytes from coelom.There was no significant difference in the expression levels of the 9 genes between the 30 g group and the 110 g group.The expression levels of AjNLRP3,AjRac1,AjToll and Aj-iLys in the 70 g group were significantly higher than those in the 30 g group,while there was no significant difference in AjTRAF3,AjMKK3/6 and AjC3 between the two groups;The expression levels of AjC3,AjAP-1 and AjTLR3 in the 70 g group was significantly lower than that in the 110 g group,and that of AjNLRP3,AjToll and Aj-iLys was significantly higher than that in the 110 g group,with no significant difference concerning expression levels of AjMKK3/6,AjRac1 and AjTRAF3 between the two groups.Based on the above results,conclusions can be drawn as such: the expression levels of immune-related genes in the coelomocytes from polian vesicle of the 30 g and 110 g groups of cultural Apostichopus japonicus are basically the same,and the difference regarding varied gene expression levels in the 70 g group,30 g group and the 110 g group was inconsistent. |
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