| In the neonatal period,piglets are susceptible to environmental factors due to their immaturity in intestinal function,with the eventual outcome of intestinal stress and associated damage,which seriously affects the survival rate of piglets during the lactation and weaning stages.Bamboo leaf extracts contain several bioactive substances such as flavonoids and polyphenols,which can promote growth and development of livestock and poultry,regulate their redox status and immune regulation.However,the effects of bamboo leaf extracts on intestinal function in piglets have not been reported so far.The aim of this experiment was to investigate the protective effects of different doses of bamboo leaf extracts on the small intestine of suckling piglets by monitoring digestibility,barrier,anti-inflammatory,and antioxidant function.The first trail evaluated the effects of bamboo leaf extracts on the growth performance and small intestinal morphology and digestive enzyme activities in suckling piglets.At 3days of age,a total of sixty-four piglets with similar body weight and parity were randomly selected and then divided into four groups.Each group consists of eight replicate with two piglets per replicate.In the control group,piglets were treated orally 0.5% sodium carboxymethyl cellulose(CMC-Na)solution daily.The treatment groups were received bamboo leaf extracts by oral route daily at a dosage of 100,200,and 300 mg bamboo leaf extracts(dispersed in the 0.5% CMC-Na solution)per kg body weight,respectively.The experiment lasted for 21 days.The results showed that:(1)Compared with the control group,the average daily gain of piglets in the three different bamboo leaf extracts-treated groups increased by 11.76%,8.76%,and 8.67%,respectively,but there was no significant change in relative growth rate among the four groups(P > 0.10).(2)Supplementation with200 mg/kg bamboo leaf extracts significantly increased villus height(VH)and the ratio of villus height to crypt depth(VH/CD)in jejunum when compared with the control group(P< 0.05);Besides,the increased VH/CD in suckling piglets was observed in the 200 mg/kg group when compared with the control group(P < 0.05),and supplementation with 300mg/kg bamboo leaf extracts significantly increased the ileal VH of suckling piglets(P <0.05),but there was no significant difference in CD and VH/CD(P > 0.10);(3)Supplementation with 100 mg/kg bamboo leaf extracts significantly increased the activities of lactase,sucrase,and maltase in the jejunum of suckling piglets;supplementation with200 mg/kg bamboo leaf extracts significantly increased the activities of lactase,sucrase,and trypsin in the jejunum of suckling piglets(P < 0.05).However,there was no significant change in jejunal disaccharidase activity when bamboo leaf extracts were supplemented at a dose of 300 mg/kg(P > 0.10).Compared with the control group,the activity of ileal maltase in the three different bamboo leaf extracts-treated groups tended to increase(0.05 <P < 0.10);Compared with the control group,supplementation with 200 mg/kg bamboo leaf extracts significantly increased the activities of ileal lactase,sucrose and trypsin in suckling piglets(P < 0.05).Taken together,supplementation with bamboo leaf extracts has the potential to improve the growth performance of suckling piglets and it promotes small intestinal morphology and digestive capacity of piglets.The optimal effect was observed when bamboo leaf extracts were supplemented at a dose of 200 mg/kg.The second experiment evaluated the effects of different doses of bamboo leaf extracts on the intestinal barrier and anti-inflammatory ability of suckling piglets.The experimental design was the same as the first trial.The results showed that:(1)Compared with the control group,serum diamine oxidase activity in bamboo leaf extracts-treated groups were significantly decreased(P < 0.05).(2)Compared with the control group,supplementation with 200 mg/kg bamboo leaf extracts tended to increase the m RNA expression of jejunal mucosal claudine 2(CLDN2)(0.05 < P < 0.10),but had no significant effects on the m RNA expression of zonula occludens 1(ZO-1)and occludin(OCLN)(P > 0.10).Supplementation with 300 mg/kg bamboo leaf extracts significantly increased the m RNA expressions of OCLN and CLDN2 in ileum mucosa of suckling piglets(P < 0.05);(3)Compared with the control group,the contents of tumor necrosis factor α(TNF-α)in the jejunal and ileal mucosa of suckling piglets were significantly decreased when bamboo leaf extracts were supplemented at a dose of either 200 or 300 mg/kg;the content of interleukin-10(IL-10)in jejunal mucosa in 300 mg/kg group was lower than that in the control group(P < 0.05);(4)Compared with the control group,the m RNA expression of TNF-α in the jejunal mucosa of piglets was significantly decreased in the 200 and 300mg/kg groups,whereas the m RNA expression of interleukin-4 was significantly increased;the m RNA expression of IL-10 in jejunal mucosa of piglets in the 300 mg/kg group was significantly increased compared with the control group(P < 0.05);the m RNA expression levels of interleukin-1β and interferon-γ in the ileal mucosa of piglets in bamboo leaf extracts-treated groups were significantly decreased relative to the control group,and the m RNA expression levels of TNF-α in ileal mucosa of piglets in the 300 mg/kg group were significantly decreased(P < 0.05).Altogether,supplementation with 200 and 300 mg/kg bamboo leaf extracts improves the intestinal anti-inflammatory ability and barrier function of suckling piglets.The third experiment evaluated the effects of bamboo leaf extracts on antioxidant capacity of serum and small intestine of suckling piglets.The experimental design was the same as the first trial.The results showed that:(1)Compared with the control group,supplementation with 200 and 300 mg/kg bamboo leaf extracts significantly decreased the content of malondialdehyde(MDA)in serum,jejunal mucosa,and ileal mucosa(P < 0.05),and significantly increased the activities of glutathione peroxidase(GSH-Px)and serum total antioxidant capacity(T-AOC)(P < 0.05).(2)Compared with the control group,100 and 200 mg/kg bamboo leaf extracts significantly increased the activities of superoxide dismutase(SOD)and catalase(CAT)in the jejunal mucosa of suckling piglets(P < 0.05),and supplementation with 300 mg/kg bamboo leaf extracts significantly increased the activity of SOD in the ileal mucosa of suckling piglets(P < 0.05).(3)Compared with the control group,supplementation with 200 and 300 mg/kg bamboo leaf extracts significantly up-regulated the m RNA expression levels of nuclear transcription factor E2-related factor 2(NRF2),GSH-Px,and CAT in the jejunal mucosa and the m RNA expression levels of NRF2 and GSH-Px in the ileal mucosa.The higher m RNA expression levels of heme oxygenase-1and SOD2 in ileal mucosa were observed in the 300 mg/kg bamboo leaf extracts-treated group relative to the control group(P < 0.05).(4)The protein expression levels of NRF2,SOD1,and SOD2 in jejunal mucosa were higher than that in the control group,with a significant increase in the protein level of NRF2(P < 0.05).Supplementation with 200mg/kg bamboo leaf extracts significantly increased the protein expressions of SOD1 and SOD2 in jejunal mucosa(P < 0.05).Compared with the control group,supplementation with 200 and 300 mg/kg bamboo leaf extracts significantly increased the protein expression levels of NRF2 and SOD2 in ileal mucosa(P < 0.05).Collectively,bamboo leaf extracts may regulate intestinal antioxidant level and improve antioxidant capacity of small intestine of suckling piglets by activating NRF2 signaling pathway.In conclusion,supplementation with bamboo leaf extracts has the potential to improve the growth performance of suckling piglets,and the effect is most significant when the dosage of bamboo leaf extracts is 100 mg/kg.In addition,supplementation with bamboo leaf extracts improves intestinal digestibility,barrier,anti-inflammatory,and antioxidant function of suckling piglets,and promotes the maturation of intestinal structure and physiological function of suckling piglets.The effects are most significant when the dose is300 mg/kg. |
