The effect of dietary tryptophan levels on oxidative stress of liver induced by diquat in weaned piglets

Oxidative stress can induce abnormal tryptophan metabolism. The present study was mainly conducted to determine the effect of dietary tryptophan levels on oxidative stress in the liver of weaned pigs challenged by diquat. A total of 36 PIC piglets weaned at 21 days of age were randomly allotted to 1 of 3 diets containing dietary tryptophan levels of 0.18, 0.30, and 0A5% for 14 d. On day 8, the piglets were injected intraperitoneally with sterile 0.9% NaCI solution or diquat （10 mg/kg body weight）. During the first 7 d of trial, increasing dietary tryptophan levels enhanced average daily gain （P = 0.09） and average daily feed intake （P = 0.08）, and decreased the feed efficiency （P 〈 0.05） of piglets. The growth performance was decreased by diquat injection （P 〈 0.05）. Diquat injection also decreased the activities of the superoxide dismutase （SOD） and glutathione peroxidase （GPx） in the plasma and liver （P 〈 0.05）, increased plasma malondialdehyde （MDA） （P 〈 0.05） and urea nitrogen （P 〈 0.05） concentrations, and enhanced MDA concentration （P = 0.09） and tryptophan 2,3-dioxygenase （TDO） activity （P = 0.07） in liver of piglets. Increasing dietary tryptophan levels could attenuate the effects of diquat injection on the MDA （P = 0.06） concentration and the activities of SOD （P = 0.09） and GPx （P = 0.05） of the liver, and plasma urea nitrogen （P = 0.06） concentration in the piglet. There was a synergistic role for increasing TDO activity in the liver between dietary tryptophan levels and diquat injection （P 〈 0.05）. These results suggest that increasing dietary tryptophan levels could attenuate the oxidative stress of the liver in weaned piglets intraperitoneally injected with diquat via enhancing the antioxidant capacity.

Tannic acid prevents post-weaning diarrhea by improving intestinal barrier integrity and function in weaned piglets

Background:Tannic acid(TA)is potential to reduce diarrhea in weaning pigs,but knowledge about the influence of TA on intestinal barrier integrity and function is still scarce.This experiment was conducted to investigate the effects of dietary TA supplementation on growth performance,diarrhea rate,intestinal barrier integrity and function of weaned pigs.Methods:A total of 108 crossbred(Duroc×Landrace×Yorkshire)piglets,with an initial average body weight of 6.60±0.27 kg,were allotted to 3 groups(6 pigs/pen and 6 replicates/group)in a randomized complete block design according to their gender and body weight.Piglets were fed the basal diet with 0(control,CON),0.2%and 1.0%TA,respectively.The trial lasted for 28 d.Results:Compared with the CON group,dietary 0.2%and 1.0%TA supplementation didn’t affect ADFI,ADG and F:G(P>0.05),but reduced diarrhea rate,diarrhea index and diarrhea score of piglets(P<0.05),reduced diamine oxidase(DAO)activity and D-lactic acid concentration in serum(P<0.01).The higher occludin expression and localization were observed in the duodenum,jejunum and ileum after supplementation with 0.2%or 1.0%TA(P<0.05).Adding 0.2%TA to diet significantly decreased crypt depth,increased villus height/crypt depth ratio in the duodenum(P<0.05),and dietary 1.0%TA tended to decrease crypt depth(P<0.10)and significantly decreased villus height(P<0.05)of the ileum.Moreover,lower malondialdehyde content in the ileum was detected in the pigs fed 1.0%TA(P<0.05).In the duodenum,both 0.2%and 1.0%TA groups had higher occludin(OCLN)mRNA and 0.2%TA group had higher zonula occludens-2(ZO-2)level(P<0.05).Meanwhile,dietary 1.0%TA supplementation tended to up-regulate OCLN mRNA levels in the jejunum(P<0.10)and 0.2%TA supplementation tended to up-regulate zonula occludens-1(ZO-1)mRNA levels in the ileum(P<0.10).Conclusion:In conclusion,dietary supplementation of 0.2%or 1.0%TA could effectively alleviate postweaning diarrhea without altering growth performance in weaned piglets,which might be achieved by improving intestinal barrier integrity and function.

Infusion of short chain fatty acids in the ileum improves the carcass traits,meat quality and lipid metabolism of growing pigs

Short chain fatty acids(SCFA)are the main products of indigestible carbohydrates undergoing bacterial fermentation in the hindgut,which are related to some physiological functions.This study was designed to investigate the effects of SCFA infusion by ileum on the carcass traits,meat quality and lipid meta-bolism of growing pigs.In a 28-day study,24 growing barrows fitted with a T-cannula in distal ileum were divided into 4 treatments:1)Control,2)antibiotics(AB),3)AB+300 mL of SCFA1 solution(ABS1),4)AB+300 mL of SCFA2 solution(ABS2).The concentrations of acetate,propionate and butyrate in SCFA1 solution were respectively 61.84,18.62 and 12.55 mmol/L,and in SCFA2 were respectively 40.08,15.41 and 9.78 mmol/L The results showed that the SCFA infusion increased the average daily feed intake and average daily gain of pigs(P<0.05).Meanwhile,the SCFA treatments increased longissimus dorsi area(P<0.05)and carcass weight(P=0.058),decreased the drip loss of longissimus dorsi(P=0.059),and reduced serum concentrations of triglyceride,total cholesterol and urea nitrogen(P<0.05).Besides,the SCFA administration inhibited the mRNA expressions of fatty acid synthase(FAS)and acetyl-CoA carboxylase in longissimus dorsi(P<0.05),the mRNA expression of FAS in the liver(P<0.05),and the mRNA expression of hormone-sensitive lipase in abdominal fat(P<0.05).Short chain fatty acid infusion also enhanced the mRNA expression of carnitine palmitoyltransferase-1αin the liver(P<0.05),the mRNA expressions of peroxisome proliferator activated receptor gamma and lipoprotein lipase in abdominal fat(P<0.05),and the mRNA expressions of free fatty acid receptor 2,glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon(P<0.05).These results suggested that SCFA administration in the ileum could improve the carcass traits and meat quality of growing pigs,which was possibly due to the fact that SCFA modulated lipid metabolism.

Tannic acid extracted from gallnut prevents post-weaning diarrhea and improves intestinal health of weaned piglets

This experiment was conducted to evaluate the effects of different levels of tannic acid(TA)on growth performance,diarrhea rate,nutrient digestibility and intestinal health in weaned piglets.A total of 180 weaned piglets(Duroc×Landrace×Yorkshire,24 d of age,initial average BW=7.77±0.17 kg)were allotted to 5 groups(6 pigs/pen and 6 replicates/group)in a randomized complete block design according to their gender and body weight.Piglets were fed a basal diet,or the basal diet supplemented with 0.05%,0.1%,0.2%or 0.4%TA for 28 d.The supplementary levels of TA in the diets were obtained by adding tannalbin containing 51%TA and 40.17%protein.The results showed that,compared with the CON group,dietary TA did not affect ADFI,ADG or F:G,and linearly reduced(P<0.01)the diarrhea rate and diarrhea index of piglets.There were no significant effects on apparent total tract digestibility(ATTD)in the 0.05%,0.1%and 0.2%TA groups,while negative effects(P<0.05)on apparent digestibility of crude protein and gross energy were observed in the 0.4%TA group.In addition,the nutrient digestibility of dry matter,crude protein and gross energy linearly decreased(P<0.01)with the increase of TA dosage.Supplementation of TA increased(P<0.05)the villus height of the duodenum and jejunum,as well as increased(P<0.05)catalase(CAT)activity in serum.Dietary TA improved(P<0.05)the Bacillus counts in cecal digesta.Further,TA significantly improved(P<0.05)Bacillus counts and reduced(P<0.05)the Escherichia coli counts in colonic digesta.The concentration of acetic acid,pro pionic acid,butyric acid and isovaleric acid in cecal digesta were significantly increased(P<0.05).The mRNA expression level of zonula occludens-1(Z0-1),zonula occludens-2(ZI-2),and claudin-2(CLDN-2)in the jejunum were greater(P<0.05)in TA supplemented groups.The study showed that,compared to the control,TA prevented post-weaning diarrhea and improved intestinal health of weaned piglets,and the appropriate level of TA supplementation would be from 0.1%to 0.2%.

Dietary pectic oligosaccharide supplementation improves rat reproductive performance via regulating intestinal volatile fatty acids during middle gestation

As a kind of green additive,pectic oligosaccharide(POS) may regulate some physiological functions of animals,such as gut health,antioxidant capacity,immunity and lipid metabolism.This study aimed to identify whether POS administration can improve maternal reproduction,and to determine the possible metabolism.A total of 48 pregnant Wistar rats randomly allotted into 2 groups,and each group was fed a diet supplemented with 0 or 800 mg/kg of POS.Pectic oligosaccharide administration increased rat born number(P <0.05),did not affect rat embryo number on d 7 of gestation,but increased rat fetus number on d 14 of gestation(P <0.05).On d 14 of gestation,POS treatment improved Lactobacillus and Bifidobacterium populations and volatile fatty acid concentrations of cecal digesta(P <0.05),hormone(progesterone and nitric oxide) and cytokine(interleukin 2) concentrations of serum(P <0.05),and antioxidant capacity of serum(increased total antioxidant capacity and decreased malondialdehyde) and placenta(increased total superoxide dismutase,decreased malondialdehyde)(P <0.05) in pregnant rats.These results suggest that POS administration improved rat reproduction via decreasing fetus loss in middle gestation.This was due to the increased volatile fatty acid concentrations in rat gut improving hormone and inflammatory-cytokine productions,and antioxidant capacity.