Effects Of Low Birth Weight On The Intestinal Development Of Piglets And The Nutritional Regulation By L-Arginine

Low birth weight(LBW)is a common phenomenon with birth weight less than 1.0 kg that is mainly caused by impaired growth and development of the mammalian embryo or its organs during pregnancy and widely exists in pig industry.In order to explore the influences of LBW on intestinal development and the nutritional regulation of LBW piglets by Arg,two experiments were conducted to investigate the effects of LBW on the intestinal development and redox status of newborn piglets and the effects of Arg supplemention on the intestinal development and functions of LBW suckling piglets.Experiment 1:Intestinal development and redox status of newborn LBW pigletsThis study was conducted to explore the effects of LBW and NBW on the intestinal development and redox status of newborn piglets.Ten couples of NBW and LBW newborn piglets from ten sows with same parturition day were selected and sampled immediately without eating colostrum.The blood sample and small intestine tissue were sampled and measured.The results showed that:compared with NBW piglets,(1)LBW significantly decreased the small intestine length.weight and the small intestine weight per length(P<0.05);(2)LBW markedly decreased the levels of leptin and insulin in serum(P<0.05),LBW have the trend to decrease the concentration of IGF1 in serum(P=0.06);(3)LBW remarkably decreased the concentrations of T-AOC?SOD and CAT and increased the content of MDA in serum(P<0.05);(4)LBW significantly decreased the villus height/crypt depth index in jejunum(P<0.05).and tend to decrease the villus height in jejunum and ileum(P=0.09).LBW also have the trend to decrease the expression of claudin1 in jejunum(P=0.O5);(5)LBW had a lower activity of CAT in jejunum(P<0.05)and tend to decrease the ability of ASA in jejunum(P=0.09).LBW also lead to a lower expression of CAT?GPx and HO1 in jejunum(P<0.05);(6)LBW induced mitochondrial vacuolation and significantly decreased the mRNA expression of PGC1?(P<0.05)and tend to decrease the expression of Ccox?(P=0.07)and Cytc(P=0.08);(7)LBW also decreased the eNOS and CAT1 mRNA expression in jejunum(P<0.05).These results indicated that,compared with NBW newborn piglets,LBW newborn piglets showed a lower levels of insulin and leptin in serum,disturbed the redox status in serum and jejunum,damaged the morphology and structure of jejunal mitochondria and decreased the genes abundance of mitochondria biogenesis and function,up-regulated the mRNA levels of Arg transport and catabolism related genes in jejunum,impaired the intestinal barrier function,decreased the development of intestine.Experiment 2:Dietary Arginine supplementation on the growth performance and intestinal development and antioxidant capacity of LBW pigletsIn the Experiment 1,we have proved that LBW exhibited an impairment development of small intestine and suffered oxidative stress in jejunum.Arg not only can improve the growth performance of young piglets,but also can against oxidative stress,so we conducted the experiment 2 to determine the effects of Arg supplementation on the growth performance and intestinal development and functions of LBW piglets.Sixteen NBW piglets and seventy-two LBW piglets were chosen at birth from seventy-two sows with the same parturition day.Newborn piglets were reared by the sows and ensure adequate colostrum intake.At 3 d,piglets were weaned and 10 couples of NBW piglets and LBW piglets and another 30 LBW piglets were chosen according to the body weight and gender.At 4 d,these piglets were allocated to five treatments,including NBW control(NBW).LBW control(LBW).LBW+0.5%Arg(0.5%Arg).LBW+1.0%Arg(1.0%Arg)and LBW+1.5%Arg(1.5%Arg).each treatment had ten piglets.The experiment lasted 21 days.At the end of the experiment,the piglets in NBW and LBW control and the best growth performance of Arg supplementation group were sampled.The results showed that:compared with NBW piglets.(1)LBW significantly impaired the growth performance of piglets(P<0.05);(2)LBW significantly decreased the contents of Orn and Ala in serum(P<0.05).and tend to decrease the level of Pro(P=0.06)in serum;(3)LBW remarkably decreased the concentrations of insulin?IGF1?IL6 and ThNF? in serum(P<0.05);(4)LBW increased the PC level and decreased the AHR ability in serum(P<0.05):(5)LBW significantly decreased the villus height/crypt depth index in duodenum and ileum as well as the expression of claudinl in jejunum(P<0.05);(6)LBW also decreased the activities of CAT and GPx but increased the ability of ASA in jejunum(P<0.05);(7)Notably,LBW increased the concentration of MDA and decreased the CAT activity in jejunum mitochondrion(P<0.05).(8)LBW increased the mRNA expression of IL1??TNF?(P=0.07)?TLR4?MyD88?p65NF-?B and p38MAPK in jejunum(P<0.05)(9)LBW significantly increased the mRNA expression of CAT1 and CAT2(P<0.05)and tend to decrease the expression of arginase2(P=0.07)in jejunum.Supplementation with proper dose of Arg can improve the growth performance of LBW piglets.Compared with LBW control group,supplementation with 0.5%Arg increased the body weight and ADG at the first week and the whole experimental period(P<0.05),1.0%Arg supplementation enhanced the body weight and ADG at the first and second week and the whole experimental period(P<0.05),supplemented with 1.5%Arg can significantly improve the growth performance at the third week and the,whole experimental period(P<0.05).Supplementation with 1.0%Arg.(1)increased the concentrations of Arg and Orn(P<0.05),and have a trend to increase the levels of Pro(P=0.06)and Glu(P=0.09)in serum;(2)increased the concentrations of insulin,IL6 and IL10 and decreased the TNFa level in serum(P<0.05):(3)enhanced the SOD activity and ASA ability and decreased the MDA level in serum(P<0.05);(4)lead to a higher level of villus height and villus height/crypt depth index in jejunum and ileum as well as the expression of claudin1 in jejunum(P<0.05),significantly increased the activities of maltase and sucrase in jejunum mucosa(P<0.05):(5)decreased the MDA level in jejunum(P<0.05).and have a trend to increase the activities of CAT(P=0.06)and GPx(P=0.09)in jejunum,markedly enhanced the mRNA expression of CAT and GPx in jejunum(P<0.05);(6)increased the activities of CAT and SOD in jejunum mitochondrion(P<0.05);(7)decreased the concentrations of IL1?IL6 and TNF? as well as the mRNA expression of IL1??TLR4?MyD88?p65NF-?B and p38MAPK in jejunum(P<0.05);(8)decreased the mRNA ambudance of CAT1 and CAT2 and increased the expression of arginase2 in jejunum(P<0.05).The results indicated that,compared with NBW piglets.LBW piglets showed a poor growth performance and decreased the concentrations of insulin and IGF1,damaged the morphology and structure of jejunum,disturbed the redox status in serum and jejunum,decreased the antioxidant capacity in jejunal mitochondria,increased the cytokines levels and the mRNA expression related to immune molecules,up-regulated the transport levels and inhibited the catabolism of Arg in jejunum.1.0%Arg supplementation increased the growth performance and promoted the hormone secretion,enhanced the digestive and barrier function in jejunum,improved the redox status in serum,jejunum and jejunal mitochondria,decreased the levels of inflammatory cytokines and the expression of immune signal molecules in jejunum,decreased the mRNA expression of CAT1 and CAT2 but increased the expression of arginase2 in jejunum.The above findings revealed that,LBW newborn piglets exhibited a lower antioxidant capacity in serum and jejunum,damaged the morphology and structure of jejunal mitochondria and decreased the genes abundance of mitochondria biogenesis and function,decreased the intestinal barrier function and inhibited the development of intestine.After 21 d rearing with formula milk,LBW piglets showed a poor growth performance,decreased the hormone levels and decreased the antioxidant ability in serum,jejunum and jejunal mitochondria,enhanced the transport metabolism and inhibited the catabolism of Arg in jejunum.1.0%Arg supplementation improved the growth performance,promoted the hormone secretion,improved the morphology structure and digestive function in jejunum,improved the redox status in serum,jejunum and jejunal mitochondria,enhanced the immune function,increased the transport metabolism and inhibited the catabolism of Arg in jejunum.