Stress and Disease Resistance in Crayfish (Procambarus clarkii) Breed “Huachizhen-1”

Stress and disease are critical factors hindering the industrial development of red swamp crayfish (Procambarus clarkii). Breeding crayfish with stress- and disease-resistant characteristics can overcome these limitations and promote their industrial development. In this study, the crayfish breed F3, which exhibits rapid growth and a favoured haplotype combination of the immune genes R, ALF, and crustin2, encoding the Toll-like receptor, anti-lipopolysaccharide factor, and antimicrobial peptide, respectively, were selected as parents to breed offspring (the selected group (SG)). The genotype, stress resistance, and disease resistance of crayfish in the SG and unselected group (USG) were compared. The results showed that the ratio of the favoured haplotype was higher in the SG crayfish than in the USG crayfish, leading to stronger stress and disease resistance. Compared to that of the USG crayfish, the mortality of the SG crayfish subjected to stress during eight days of transport and challenged with bacteria (Aeromonas hydrophila or Vibrio parahaemolyticus) or white spot syndrome virus were significantly reduced by 60% and 20%, respectively (p < 0.05). Based on these results, the stress- and disease-resistant SG crayfish were named the “Huachizhen-1” breed. Additionally, the ratio of the unfavoured homozygous genotypes of R, ALF, and crustin2 sharply decreased, whereas those of the heterozygous genotypes increased together with stress and disease resistance during crayfish maturation under natural conditions, indicating that the heterozygotes of these genes also exhibit strong stress and disease resistance. All of this taken together, the crayfish breed “Huachizhen-1” may be applicable for improving stress and disease resistance and the production of crayfish.