Within-litter covariance of allele-specific MHC heterozygosity, coccidian endoparasite load and growth is modulated by sibling differences in starting mass

摘要: Although littermates in altricial mammals usually experience highly similar environmental conditions during early life, considerable differences growth and health can emerge among them. In a study on subadults of European rabbit (Oryctolagus cuniculus) population with low MHC polymorphism, we tested whether litter-sibling endoparasitic coccidia load body mass at the end vegetation period were associated within-litter starting (measured around 2 weeks prior to weaning) immune-genetic (MHC class II DRB) constitution. We hypothesized that siblings lighter might be more susceptible endoparasite infections thus, negative effects unfavourable constitution particularly pronounced such individuals. Within-litter comparisons revealed animals reached relatively lower autumn. Furthermore, there indications for an allele-specific heterozygote advantage, as heterozygous combinations allele Orcu-DRB*4 had hepatic loads than their certain homozygous combinations. Consistent our hypothesis, significantly higher tendentially autumn masses compared individuals evident initially but not heavier siblings, suggesting synergistic between light mass. Taken together, these lead notable fitness litter high burden are key factors limiting young rabbits’ survival winter.