Behavioural genetic differences between Chinese and European pigs.

Aggression is a heritable trait and genetically related to neurotransmitter-related genes. Behavioural characteristics of some pig breeds are different. To compare the genetic differences between breeds, backtest and aggressive behaviour assessments, and genotyped using Sequenom iPLEX platform were performed in 50 Chinese indigenous Mi pigs and 100 landrace-large white (LLW) cross pigs with 32 SNPs localized in 11 neurotransmitter-related genes. The genetic polymorphisms of 26 SNPs had notable differences (P < 0.05) between Mi and LLW. The most frequent haplotypes were different in DBH, HTR2A, GAD1, HTR2B,MAOA and MAOB genes between Mi and LLW. The mean of backtest scores was significantly lower (P < 0.001) for Mi than LLW pigs. Skin lesion scores were greater (P < 0.01) in LLW pigs than Mi pigs. In this study, we have confirmed that Chinese Mi pigs are less active and less aggressive than European LLW pigs, and the genetic polymorphisms of neurotransmitter-related genes, which have been proved previously associated with aggressive behaviour, have considerable differences between Mi and LLW pigs.