The Mechanism Of Nutritional Regulation Of Dietary Conjugated Linoleic Acid Supplementation During Late Gestation On Colostral IgG In Sows

Four experiments including both feeding trails and in vitro studies were conducted in this study to investigate the effects of conjugated linoleic acid(CLA)supplementation in late gestation on reproductive performance,colostrum yield,and immunoglobulin G(IgG)production of primiparous and multiparous sows and its possible mechanism.In Exp.1,forty-eight pregnant Landrace × Large White multiparous sows were allotted to 1 of 4 weight-and parity-matched groups(n = 12 for each treatment)supplemented with 0%(CON),0.75%,1.50%or 2.25%CLA from d 85 of gestation to farrowing.The results showed that dietary CLA did not affect the reproductive performance and the calculated colostrum production of sows as well as the growth of suckling piglets.Supplementation with CLA increased the IgG concentrations in the colostrum and the serum of sows at d 112 of gestation and in the serum of neonatal piglets(P<0.05),whereas there were no differences within the CLA treatments.In Exp.2,twenty-four primiparous Landrace × Large White pregnant sows were randomly selected and assigned to four dietary treatments(n = 6 for each treatment),0%(CON),0.75%,1.50%and 2.25%CLA supplementation from d 85 of gestation to parturition.Results showed that the reproductive performance and colostrum yield were not influenced by CLA supplementation during late gestation in primiparous sows.Compared with CON group,1.5%and 2.25%CLA group increased colostral IgG concentration(P<0.05),and 2.25%CLA group also increased the IgG concentration in the serum of neonatal piglets(P<0.05)and decreased the preweaning mortality of suckling piglets(P<0.05).In Exp.3,porcine peripheral blood mononuclear cells(PBMCs)were used to evaluate the effects of different levels of cis-9,trans-11(c9,t11)CLA,trans-10,cis-12(t10,c12)CLA and their 1:1 mixture on the in vitro proliferation and IgG production under the stimulation of pokeweed mitogen(PWM).Results showed that,the PWM-stimulated proliferation increased significantly at 12.5?M and 25 ?M for t10,c12-CLA,and decreased significantly starting at 50?M for c9,t11-CLA,100 ?M for t10,c12-CLA and 1:1 c9,t11-CLA and t10,c12-CLA mixture(P<0.05).In addition,the IgG production in PWM-stimulated porcine PBMCs was significantly increased at the concentration of 12.5 ?M for c9,t11-CLA,12.5 and 25?M for t10,c12-CLA,and 25?M for CLA mixture(P<0.05).The Exp.4 was conducted based on Exp.,3 to further evaluate the effects of t10,c12-CLA on the cytokine and protein kinase C(PKC)production as well as the IgG production.The effects of G-protein coupled receptor 120(GPR120)agonist(GW9508)on the IgG production and the protein expression of GPR120 were also studied.Results showed that,t10,c12-CLA increaded the producton of IL-2 and PKC,and decreased the producton of IFN-?(P<0.05).Both the t10,c12-CLA and its combination with G W9508 increased the production of IgG(P<0.05).The GPR120 protein expression was increased by t10,c12-CLA,GW9508 and their combination(P<0.05).In summary,dietary CLA supplementation during late gestation could increased the colostral IgG concentrations of primiparous and multiparous sows,and t10,c12-CLA may play a more important role in promoting the IgG production.