Effects Of Dietary Lactic Acid,Glutamine And Liquid Feeding On Growth Performance And Gut Health Of Weaning Piglets

Adopting nutritional techniques to improve gut health and feed intakes of piglets is an effective way to solve the problem of diarrhea and growth check after weaning.Feed additives and feeding patterns are important factors affecting gut health and growth performance of piglets after weaning.Therefore,two experiments were conducted to study the effects of dietary lactic acid,glutamine,and liquid feeding on growth performance and gut health of weaning piglets and their related mechanisms.The results of this study will provide theoretical support for lactic acid,glutamine and liquid feeding to improve growth performance and gut health of weaning piglets,and provide scientific data for protecting weaning piglets from losing weight after weaning.Experiment 1.Effects of dietary lactic acid,glutamine and their combined supplementation on growth performance and gut health in weaning pigletsThis experiment was conducted to investigate the effects of dietary lactic acid,glutamine and their combined supplementation on growth performance and gut health in weaning piglets.According to initial body weight(BW)and sex,a total of 96 DLY piglets(Duroc×Landrace×Yorkshire,7.24 ± 0.03 kg)with 24±1 days of old were randomly assigned to four treatments.Treatments included: Basal diets(CON);2% lactic acid group(LS);1% glutamine group(GS);2% lactic acid +1% glutamine group(LGS)with 6 replicates per treatment and 4 piglets per replicate.The trial lasted for 27 days.The results showed that:(1)When compared with CON group,LS group increased(P=0.086)ADG on day 1 to 7 of piglets.In addition,when compared with CON group,the index of diarrhea of LS group decreased(P<0.05).When compared with CON group,LS group increased(P<0.05)the digestibility of CP,the content of IGF-1 and GH in serum,the activities of amylase and lipase in jejunal mucosa,and villus height as well as villus height to crypt depth of jejunum.Moreover,LS group increased(P=0.061)the digestibility of DM.When compared with CON group,LS group up-regulated(P<0.05)the mRNA expression levels of GLUT2,IGF-1,TGF-?2,Occludin and ZO-1 in jejunal mucosa,moreover,LS group increased(P=0.054,P=0.066,P=0.093,P=0.088)the mRNA expression levels of SGLT1,IGF-1R,Claudin-2,and ZO-2.When compared with CON group,LS group significantly increased(P<0.05)populations of total bacteria,Lactobacillus and content of butyric acid in colonic digesta as well as Bifidobacterium in cecal digesta,moreover,LS group increased(P=0.060)total bacteria population in cecal digesta.(2)When compared with CON group,GS group increased(P<0.05)the digestibility of ash,the content of IGF-1 and GH in serum,and villus height to crypt depth of jejunum,in addition,GS group increased(P=0.064)villus height of jejunum.When compared with CON group,GS group up-regulated(P<0.05)the mRNA expression levels of SGLT1,GLUT2,PepT1,GLP-2,IGF-1,TGF-?2,IGF-1R and Occludin in jejunal mucosa,moreover,GS group increased(P=0.083,P=0.077)the mRNA expression levels of Claudin-2 and ZO-1.(3)The final body weight on day 27 and ADG on day 1 to 27 of LGS group improved(P<0.05)compared with CON group.Meanwhile,compared to CON group,LGS group increased(P=0.054,P=0.078,P=0.087,P=0.078)ADG on day 1 to 7,ADFI and ADG on day 8 to 27 as well as ADG on day 1 to 27,in addition,the index of diarrhea of LSG group decreased(P<0.05).When compared with CON group,the digestibility of CP and ash of LGS group increased(P<0.05),moreover,LGS group increased(P=0.053,P=0.063)the digestibility of DM and EE.When compared with CON group,LGS group had higher(P<0.05)content of IGF-1 in serum and lower(P=0.089)content of low density lipoprotein,in addition,LGS group had higher(P=0.067)content of GH in serum compared with CON group.When compared with CON group,the activities of amylase and lipase in jejunal mucosa of LGS group significantly increased(P<0.05).LGS group significantly increased(P<0.05)the villus height and villus height to crypt depth of jejunum compared with CON group.When compared with CON group,LGS group up-regulated(P<0.05)the mRNA expression levels of SGLT1,GLUT2,PepT1,GLP-2,IGF-1,TGF-?2,IGF-1R,Occludin and ZO-1 in jejunal mucosa,in addition,LGS group increased(P=0.071)the mRNA expression level of ZO-2.When compared with CON group,LGS group significantly increased(P<0.05)populations of total bacteria,Lactobacillus and Bifidobacterium in cecal and colonic digesta as well as the content of acetic acid,butyric acid and total VFA in cecal digesta,moreover,LGS group increased(P=0.059)content of propanoic acid in cecal digesta.In conclusion,dietary supplementation with 2% lactic acid and 1% glutamine could significantly promote nutritional metabolism via improved intestinal barrier function and digestive function of piglets,thereby improving growth performance of piglets.Their combined supplementation had synergistic effects on improving intestinal barrier function and digestive function of piglets.Experiment 2.Effects of liquid feeding on growth performance and gut health in weaning pigletsThis experiment was carried out to deterimine the effects of liquid feeding on growth performance and gut health in weaning piglets.According to initial body weight,a total of 360 healthy DLY piglets(Duroc×Landrace×Yorkshire,6.99 ± 0.15 kg)with 24±1 days of old were randomly assigned to two treatments.Treatments included: Basal diet with dry feeding(DF);Basal diet with liquid feeding(LF)with 6 replicates per treatment and 30 piglets per replicate.The trial lasted for 7 days.The results showed that:When compared with DF group,(1)Piglets in LF group had greater(P<0.05)final BW,ADG and ADFI,and decreased(P=0.056)the index of diarrhea;(2)The digestibilities of EE and ash of LF group were greater(P<0.05);LF group significantly increased(P<0.05)the content of triglyceride in serum.In addition,the content of cortisol in serum of LF group was greater(P<0.05).D-lactate concentration and the activity of diamine oxidase in serum of LF decreased(P<0.05);(3)The activities of lipase,amylase and lactase in jejunal mucosa of LF group were higher(P<0.05);(4)LF group increased(P<0.05)the villus height and the ratio of villus height to crypt height in the jejunum.In addition,crypt depth in jejunum of piglets in LF group was lower(P=0.083)than that of piglets in DF group;(5)LF group up-regulated(P<0.05)the mRNA expression levels of IGF-1R,Claudin-2,ZO-1 and ZO-2 in jejunal mucosa of piglets;In addition,LF group increased(P=0.070)Occludin mRNA expression level in jejunal mucosa;(6)LF group decreased(P<0.05)the numbers of total bacteria and Escherichia coli in cecal digesta;the concentration of butyric acid in cecal digesta of LF group was greater(P<0.05).In addition,acetic acid concentration in the cecal digesta of LF group increased(P=0.058)compared with DF group.In conclusion,liquid feeding could significantly improve intestinal barrier function and digestive function of piglets during the first week after weaning,thereby improving growth performance.In summary,our experiments indicated that: Dietary supplemention with 2 % lactic acid or/and 1% glutamine as well as liquid feeding(meal mixed with water in the ratio 1:4)after weaning could significantly improve intestinal barrier and digestive function of piglets,increase digestibity of nutrients,reduce diarrhea,thereby improving growth performance and alleviating “weaning stress syndrome”.