Effects Of ?-1,3-glucans Supplementation On Growth Performance,Immunity,Intestinal Health Of Weaning Piglets

As functional polysaccharide,?-1,3-glucans show multiple biological activities and function such as immunomodulation,intestinal health and growth performance promotion.Antibiotics have gradually been forbidden in feed industry,it is a problem that attracts people's attention.The source,structure,molecular weight and supplementation level of?-glucans have played important roles in animal performance and health status.Thus,this study chose ?-1,3-glucans to be material,aimed to determine effects of ?-1,3-glucans supplementation on growth performance,intestinal health and immunity of weaning piglets.This work included two experiments.Trial 1 Effects of ?-1,3-glucans(300KD)supplementation on growth performance,immunity,intestinal health of weaning piglets40 healthy DLY piglets were randomly assigned into five dietary groups with 8 replicated per group and 1 piglet per replicate for 28 d.The treatments contained basal diet(control group),basal diet with 25,50,100 mg/kg ?-1,3-glucans(300KD)and lg/kg yeast.The results were as follows:(1)On days 1-14,diets supplemented with 300KD ?-1,3-glucans increased ADG(P=0.047);Diets with 50mg/kg ?-1,3-glucans(300KD)supplementation dramatically increased ADG(P=0.047).On days 15-28,Diets supplemented with 100 mg/kg?-1,3-glucans(300KD)increased F/G(P=0.047).On days 1-56,growth performance including ADFI,ADG and F/G had no prominent responses to ?-1,3-glucans(300KD).(2)Diets added with ?-1,3-glucans(300KD)increased contents of ALB(P=0.041),GOD(P=0.003)GOT(P=0.023)and GPT(P=0.035)on day 14.Piglets given 50mg/kg?-1,3-glucans(300KD)showed high value of TP(P=0.047)and ALB(P=0.006)on day 28.(3)Diets with 50-100 mg/kg ?-1,3-glucans(300KD)increased Bifidobacterium contents(P=0.036)in cecum of piglets.(4)Piglets showed the highest concentration of neutrophil(P=0.026)with 25 mg/kg P-1,3-glucans(300KD).Diets added with 50-100mg/kg ?-1,3-glucans(300KD)increased CD3+CD4+ concentration(P=0.001)and CD4+/CD8+(P=0.001)on 14 d,and had no significant effects on T-lymphocyte subset on 28 d(P>0.05).(5)Diets supplemented with 100mg/kg ?-1,3-glucans(300KD)decreased IL-6(P=0.047).On day 28,diets supplemented with 100mg/kg ?-1,3-glucans(300KD)increased TNF-a(P=0.009)and IL-6(P=0.021).IgG showed the high value in piglets fed 50 mg/kg ?-1,3-glucans(300KD)on day 28(P=0.001).Trial 2 Effects of ?-1,3-glucans(2000KD)supplementation on growth performance,immunity,intestinal health of weaning piglets42 healthy DLY piglets were randomly assigned into six dietary groups with 7 replicated per group and 1 piglet per replicate for 56 d.The treatments contained basal diet(control group),basal diet with lg/kg yeast,appropriate dose of ?-1,3-glucans(300KD)and 25,50,100 mg/kg ?-1,3-glucans(2000KD).The results were as follows:(1)On days 1-56,growth performance had no prominent response to ?-1,3-glucans(2000KD)(P>0.05).(2)Diets added with 50 mg/kg ?-1,3-glucans(2000KD)increased GPT(P=0.027)of piglets on day 56.(3)Diets with 25mg/kg ?-1,3-glucans(2000KD)reduced the concentration of E.coil in cecum of piglets(P=0.002).(4)Diets supplemented with 25-50mg/kg ?-1,3-glucans(2000KD)increased neutrophil contents on 14 d(P=0.032).And 100mg/kg ?-1,3-glucans(2000KD)increased contents of lymphocyte(P=0.041)on 14 d.(5)?-1,3-glucans(2000KD)increased concentration of IL-2(?=0.036)on day 14 and TNF-a on day 42 and 56(P=0.019;P=0.016,respectively).IgM showed the high value in piglets fed 50-100 mg/kg ?-1,3-glucans(2000KD)on day 56(P=0.032).The conclusions of this study were as follows:Diets supplemented with 300KD ?-1,3-glucans significantly improved growth performance of weaning piglets on days 1-14,while diets supplemented with 2000 KD?-1,3-glucans had no dramatic effects on growth performance of weaning piglets.?-1,3-glucans with two molecular weight may regulate immunity ability of piglets,On day 14,2000KD ?-1,3-glucans showed stronger effects on immunity regulation than 300KD?-1,3-glucans;On day 56,300KD ?-1,3-glucans showed stronger effects on immunity regulation than 2000KD ?-1,3-glucans.Concentration of E.coil and Bifidobacterium showed the best when piglets fed 50 mg/kg ?-1,3-glucans(300KD)and 25 mg/kg?-1,3-glucans(2000KD),respectively.