This study investigates the effect of early gestational diet on the vulnerability of the male fetus to perturbation of the developing immune system.
A sex specific response to infectious disease in neonates has been reported with females displaying a more robust cell mediated and humoral response[1]. In a unique series of experiments we are the first to show that the male foetal calf has enhanced susceptibility to early gestational diet as it shows significantly greater vulnerability; affecting male fetal growth (p=0.01) placenta (p=0.04) and importantly immune system development; including thymus growth (p=0.04), antimicrobial use in neonate (p=0.05) and protective immunity for clostridial diseases assessed via IFNg and IL-13.
These findings support our previous studies [2] that show male and female foetuses institute different mechanisms via the placenta in response to altered environment in the development of the immune system.
Bos indicus cross heifers (n=350) were individually fed high (14%) or low (7%) crude protein (CP) from 60 days prior to conception. At 23 days post-conception the two groups were further split into high or low % CP creating four treatment groups: High/High (HH), Low/High (LH), High/Low (HL) and Low/Low (LL).
Fetal size was reduced by the low protein diet with this effect being greater in the male at 36dpc(p=0.001). At 98dpc fetal measures and organ development were measured (n=48). Low protein decreased male thymus and placental size (p=0.04). Low first trimester protein increased neonatal antimicrobial use. At 10mth of age (post clostridial vaccination) protective immunity assessed via IFNg and IL-13 assessment showed periconception low protein reduced (p=0.05) IFNg in male calves.
Conclusion:Protein supplementation during the pre breeding and periconception period in range heifers may increase immune function in the neonate and juvenile and decrease susceptibility to contagious disease.