Effects Of Feed Intake Level On The Immunity States Of Gilts And Embryos During Early Pregnancy

Sixty three crossbred gilts(Landrace×Yorkshire) were used to investigate the effects of nutrition levels(DE:3.20Mcal/kg;CP:13.10%) on maternal immunoglobulins(IgG, IgA,IgM) concentration in serum and interferon-α(IFN-α),interferon-β(IFN-β), interferon-γ(IFN-γ),myxo-virus resistance(Mxl),Toll-like receptor4(TLR4), interleukin-10(IL-10),tumor necrosis factor-α(TNF-α) mRNA expression in uterus and embryos and embryonic survival during early pregnancy.The gilts were randomly allocated to three feed intake levels(High:2.73kg/d;Medium:1.64kg/d;Low:0.82kg/d) after mating. There were three replicates each replicate including seven gilts in every feed intake level.Gilts were slaughtered on d12,25 and 35 of pregnancy,serum,uterus and embryos were collected.Nephelometry was applied to determine the maternal immunoglobulins concentration in serum,and real time-quantitative RT-PCR was applied to determine the genes expression difference in uterus and embryos.The results were as follows:1.Feed intake level significantly influenced maternal immunoglobulins concentration in serum during early pregnancy.IgG concentration in serum on d12 of pregnancy were very significantly greater in M than in L(P＜0.01) and greater in H than in L(P＜0.05),and IgG concentration in serum on d25,35 were very significantly greater in H and M than in L(P＜0.01);IgA concentration in serum on d12 of pregnancy were greater in H and M than in L(P＜0.05),and IgA concentration in serum on d25,35 were very significantly greater in H and M than in L(P＜0.01);IgM concentration in serum on d12,25 of pregnancy were greater in H and M than in L(P＜0.05),and IgM concentration in serum on d35 were very significantly greater in H and M than in L(P＜0.01) but no difference between H and M(P＞0.05).2.Feed intake level significantly influenced the immune-related gene expressions in uterus and embryos during early pregnancy.IFN-α,IFN-β,IFN-γ,Mxl,TLR4 and IL-10 genes' expression were greater in M than in L(P＜0.05),but TNF-αgenes' expression were greater in L than in M(P＜0.05) and no difference between H and M(P＞0.05).3.Feed intake level significantly influenced embryonic survival during early pregnancy in gilts.Embryonic survivals on d12 of pregnancy were greater in M than in H(P＜0.05) and no difference between M and L(P＞0.05),and embryonic survival on d25,35 were greater in M than in H and L(P＜0.05) and no difference between H and L(P＞0.05).Conclusions:1.Feed intake level significantly influenced embryonic survival during early pregnancy in gilts.Gilts were fed with allowance of 1.2 times requirement of maintenance in d0-35 of pregnancy,but high feed intake and serious restricted feeding would decrease embryonic survival during early pregnancy.2.High and medium feed intake level improved the maternal and embryonic immunoprotection.Medium feed intake level had the trend to up regulate the expression of immune-related genes Mxl,IFN-α,IFN-β,IFN-γ,TLR4,IL-10 but to down regulate the expression of TNF-αin uterus and embryos.3.Low nutrition level significantly decreased the maternal immunoglobulins concentration and down regulated the expression of immune-related genes Mxl,IFN-α, IFN-β,IFN-γ,TLR4,IL- 10 in uterus and embryos and may had detrimental effects on the survival of early embryo.