Effect Of Dietary Supplementation Of Homoarginine On Oxidative Stress,Immunity And Reproductive Performance On Pregnant Sows

Oxidative stress in the placenta during gestation is associated with the occurrence of adverse pregnancy outcomes in sows,and functional amino acids have important regulatory functions in the development of the placenta in pregnant pigs.Homoarginine(h Arg)is a nonessential amino acid that is consumed in food and is synthesized from lysine and arginine in both animals and human.It plays biological function in many biological processes through the nitric oxide pathway in different organs.The concentration of h Arg in peripheral blood of sows during gestation has been found to be higher than that during non-gestation,and the concentration of h Arg increased firstly and then decreased in late gestation with the start of gestation especially in early gestation.This experiment was conducted to investigate the effects of h Arg supplementation on oxidative stress,immune indices and reproductive performance of pregnant sows.The objective of the current study were to investigate:(1)the effect of dietary supplementation of homoarginine on oxidative stress and inflammation of pregnant sows.(2)The effect of dietary supplement of homoarginine on the immunity of pregnant sows and(3)the effect of dietary supplementation of homoarginine on the reproduction performance of pregnant sows.In this study,40 gestating sows were randomly divided into 4 groups with 10 sows(n = 10)in each group.They were fed different concentrations of homoarginine(0.005%,0.01% and 0.1%)on the basis of the regular diet until 21 days after parturition.The experimental treatments were as follows: control group without homoarginine supplementation,treatment group 1(T1)was supplemented with 0.005%h Arg diet,treatment group 2(T2)was supplemented with 0.01%h Arg,treatment group 3(T3)was supplemented with 0.1%h Arg.The routine diet was formulated according to the nutritional requirements of NRC(2012)for pregnant pigs,and the crude protein,digestible energy and amino acids in the diet were consistent.Blood samples were collected from jugular vein on the 60 th and 90 th days of pregnancy to measure blood physiological and biochemical indexes,and analyze oxidative stress and immune capacity indices,that is,the activities of superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)and total antioxidant capacity(T-AOC)in plasma of pregnant sows were measured.The concentrations of cytokines which includes interleukin-6(IL-6),interleukin-8(IL-8),tumor necrosis factor alpha(TNF-α)and interferon gamma(INF-γ)were also measured in pregnant sows plasma.Litter size,piglet birth weight and litter birth weight of all sows in each group were recorded during sow’s parturition,and piglet weight was recorded at day 21 after parturition.Effects of dietary Homoarginine supplementation on antioxidant stress and placental inflammation in pregnant sows.The concentration of 0.005% homoarginine at day 60 of gestation significantly increased the content of plasma GSH(P < 0.01).The 0.01% homoarginine concentration increased the GSH activity,SOD activity and T-AOC level in the plasma significantly(P < 0.01).The plasma GSH activity and plasma T-AOC level of sows fed in 0.1% homoarginine significantly increased at P < 0.05.On day 90,SOD and GSH activities in the plasma were significantly high regulated by 0.005% homoarginine(P < 0.01).The SOD activity and T-AOC level in the plasma were significantly high on sows fed in 0.01% homoarginine concentration(P < 0.01),and the activity of plasma GSH was significantly increased in sows fed by 0.1% homoarginine concentration(P < 0.01),but the plasma SOD activity was not affected(P > 0.05).The results of inflammatory cytokines in placenta showed that 0.001% and 0.1% homoarginine concentrations had no significant effect on the plasma TNF-α expression(P > 0.05),but 0.005% and 0.01% homoarginine concentrations significantly decreased the plasma INF-γ and IL-6(P > 0.05).Effects of dietary Homoarginine supplementation on immune function of pregnant Sows.The contents of total protein(TP),albumin(ALB),total cholesterol(TC),triglyceride(TG)and immunoglobulin A(Ig A)in blood were determined by Elisa kits.The results of serum immune indexes on day 60 and 90 of gestation showed that 0.005% and 0.01% homoarginine concentration significantly increased the total protein level(P > 0.05).The contents of total cholesterol and triglyceride in the blood were not significantly affected by different supplemental concentrations of homoarginine(P > 0.05).However,the three concentrations of homoarginine supplementation significantly affected the level of serum immunoglobulin A(P < 0.05).Effects of dietary Homoarginine supplementation on reproductive performance of pregnant Sows.Litter size,piglet birth weight and litter birth weight of all sows in each group were recorded at sow’s parturition,and piglet weight was recorded at 21 days after parturition.The results showed that 0.005% homoarginine concentration increased the average litter size(P < 0.05),while 0.1% homoarginine concentration had the lowest litter size.There were no significant effects of homoarginine supplementation on birth weight of piglets(P < 0.05).At 21 days of age,the 0.005% homoarginine concentration group showed higher piglet body weight.In conclusion,dietary supplementation with 0.005% concentration of homoarginine can alleviate oxidative stress response in sows during pregnancy and may serve as a potential antioxidant in pregnant sows in the future.Homoarginine enhances immune response by decreasing the expression of inflammatory factors during pregnancy.In addition,0.005% and 0.01% concentration of homoarginine in the diet can improve litter size and daily gain,which is of great significance to improve the efficiency of pig production industry.