The Role Of 5-HT1A Receptors In Phenotypic Differentiation Of Aggressive Behavior In Sebastes Schlegelii

In this study,juvenile Sebastods schlegelii was selected as experimental object.Based on the accurate classification of individuals with high and low aggression differences in the binary attack modes,the behavioral characteristics and physiological responses of individuals with high and low aggression were analyzed.The expression pattern of 5-HT1A receptor gene in the phenotypic differentiation of S.schlegelii was clarified by verifying the 5-HT1A receptor gene and promoter sequences of S.schlegelii,and determining the gene expression levels at different stages of aggressive behavior.Finally,the SNPs associated with phenotypic differentiation of aggressive behavior were screened.To reduce the attack behavior and improve the welfare of fish,aggressive behavior of high and low aggressive S.schlegelii under dual aggression mode was quantified in this study.The activity levels of cortisol and brain monoamines were measured and the correlations between their behavioral characteristics and physiological responses were also analyzed.In addition,effects of5-HT1A receptor agonist 8-OH-DPAT on aggressive behavior of S.schlegelii were analyzed.Results showed that the differences in aggression between individuals within a short period of time could be quantified by behavioral indicators such as individual motion status,body state and individual position distribution,especially the stationary time associated with cortisol levels and the distance to the center related to cerebral monoamines.The results demonstrated that 5-HT1A receptors can significantly influence the aggressive behavior of S.schlegelii.This study provides a reference for the study of aggression behavior,stress level and monoaminergic system,and provides a simple and feasible method for accurately quantifying fish aggression,which lays a theoretical foundation for controlling fish aggression and improving fish welfare.Severe aggression and cannibalistic behavior of S.schlegelii is the main reason that prevent the reproduction of S.schlegelii.The effects of genetic factors,especially 5-HT-related genes,on aggression behavior of S.schlegelii are not yet clear.In this study,the sequences and promoters of5-HT1Aα and 5-HT1Aβ genes were verified and proofread by PCR direct sequencing method.RTq PCR was used to detect the S.schlegelii 5-HT1Aα and 5-HT1Aβ genes at 10 min,30 min,1 h,2h,4 h and 8 h of attack,and the expression levels of the 5-HT1Aα and 5-HT1Aβ receptor subtypes in brain,liver and intestine of MRNA.The full-length sequences of 5-HT1Aα and 5-HT1Aβ were obtained.The expression of 5-HT1Aα and 5-HT1Aβ genes differed significantly in S.schlegelii aggressive individuals.Two paralogous genes of 5-HT1A receptor showed similar expression in S.schlegelii aggressive behavior.Moreover,the regulation of aggressive behavior by 5-HT1A receptor genes is related to the HPI axis and the energy metabolism level.These results will provide a reference for clarifying the mechanism of aggressive behavior and reducing aggressive behavior in S.schlegelii.Considering the important role of the 5-HT1A receptor gene in regulating fish aggression,we screened the CDS coding region and the SNPs of 5-HT1A receptor gene promoter region with different aggression phenotypes using PCR direct sequencing.The results showed that the CDS coding region had no SNPs significantly associated with differences in aggression phenotypes,while the 5-HT1Aα promoter region had 2 SNPs significantly associated with differences in aggression phenotypes,and the 5-HT1Aβ promoter region had 7 SNPs significantly associated with differences in aggression phenotypes.The results provide a reference for the selection breeding assistance markers and genetic mechanism of aggressive behavior in S.schlegelii.