Dietary supplementation of zinc oxide modulates intestinal functionality during the post-weaning period in clinically healthy piglets

Background To improve our understanding of host and intestinal microbiome interaction,this research investigated the effects of a high-level zinc oxide in the diet as model intervention on the intestinal microbiome and small intestinal functionality in clinically healthy post-weaning piglets.In study 1,piglets received either a high concentration of zinc(Zn)as zinc oxide(Zn O,Zn,2,690 mg/kg)or a low Zn concentration(100 mg/kg)in the diet during the post weaning period(d 14–23).The effects on the piglet's small intestinal microbiome and functionality of intestinal tissue were investigated.In study 2,the impact of timing of the dietary zinc intervention was investigated,i.e.,between d 0–14 and/or d 14–23 post weaning,and the consecutive effects on the piglet's intestinal functionality,here referring to microbiota composition and diversity and gene expression profiles.Results Differences in the small intestinal functionality were observed during the post weaning period between piglets receiving a diet with a low or high concentration Zn O content.A shift in the microbiota composition in the small intestine was observed that could be characterized as a non-pathological change,where mainly the commensals inter-changed.In the immediate post weaning period,i.e.,d 0–14,the highest number of differentially expressed genes(DEGs)in intestinal tissue were observed between animals receiving a diet with a low or high concentration Zn O content,i.e.,23 DEGs in jejunal tissue and 11 DEGs in ileal tissue.These genes are involved in biological processes related to immunity and inflammatory responses.For example,genes CD59 and REG3G were downregulated in the animals receiving a diet with a high concentration Zn O content compared to low Zn O content in both jejunum and ileum tissue.In the second study,a similar result was obtained regarding the expression of genes in intestinal tissue related to immune pathways when comparing piglets receiving a diet with a high concentration Zn O content compared to low Zn O content.Conclusions Supplementing a diet with a pharmaceutical level of Zn as Zn O for clinically healthy post weaning piglets influences various aspects intestinal functionality,in particular in the first two weeks post-weaning.The model intervention increased both the alpha diversity of the intestinal microbiome and the expression of a limited number of genes linked to the local immune system in intestinal tissue.The effects do not seem related to a direct antimicrobial effect of Zn O.

Dietary glutamine,glutamate,and aspartate supplementation improves hepatic lipid metabolism in post-weaning piglets

A previous study has demonstrated that early weaning significantly suppressed hepatic glucose metabolism in piglets.Glutamate(Glu),aspartate(Asp)and glutamine(Gln)are major metabolic fuels for the small intestine and can alleviate weaning stress,and therefore might improve hepatic energy metabolism.The objective of this study was to investigate the effects of administration of Glu,Asp and Gln on the expression of hepatic genes and proteins involved in lipid metabolism in post-weaning piglets.Thirty-six weaned piglets were assigned to the following treatments:control diet(Control;basal diet+15.90 g/kg alanine);Asp,Gln and Glu-supplemented diet(Control+AA;basal diet+1.00 g/kg Asp+5.00 g/kg Glu+10.00 g/kg Gln);and the energy-restricted diet supplemented with Asp,Gln and Glu(Energy^-+AA;energy deficient diet+1.00 g/kg Asp+5.00 g/kg Glu+10.00 g/kg Gln),Liver samples were obtained on d 5 and 21 post-weaning.Piglets fed Energy^-+AA diet had higher liver mRNA abundances of acyl-CoA oxidase 1(ACOX1),succinate dehydrogenase(SDH),mitochondrial transcription factor A(TFAM)and sirtuin 1(SIRT1),as well as higher protein expression of serine/threonine protein kinase 11(LKB1),phosphor-acetyl-CoA carboxylase(P-ACC)and SIRT1 compared with piglets fed control diet(P<0.05)on d 5 post-weaning.Control+AA diet increased liver malic enzyme 1(ME1)and SIRT1 mRNA levels,as well as protein expression of LKBl and P-ACC on d 5 post-weaning(P<0.05).On d 21 post-weaning,compared to control group,Glu,Gln and Asp supplementation up-regulated the mRNA levels of ACOX1,ME1 and SIRT1(P<0.05).These findings indicated that dietary Glu,Gln and Asp supplementation could improve hepatic lipid metabolism to some extent,which may provide nutritional intervention for the insufficient energy intake after weaning in piglets.

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.

Developmental changes in intercellular junctions and Kv channels in the intestine of piglets during the suckling and post-weaning periods

Background： The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate the postnatal and developmental changes in morphology, intercellular junctions and voltage-gated potassium（Kv） channels in the intestine of piglets during the suckling and post-weaning periods.Results： Samples of the small intestine were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age. The results showed that the percentage of proliferating cell nuclear antigen（PCNA）-positive cells and alkaline phosphatase（AKP） activity, as well as the abundances of E-cadherin,occludin, and Kv1.5 m RNA and claudin-1, claudin-3, and occludin protein in the jejunum were increased from d 1to d 21 during the suckling period（P 〈 0.05）. Weaning induced decreases in the percentage of PCNA-positive cells,AKP activity and the abundances of E-cadherin, occludin and zonula occludens（ZO）-1 m RNA or protein in the jejunum on d 1, 3 and 5 post-weaning（P 〈 0.05）. There were lower abundances of E-cadherin, occludin and ZO-1m RNA as well as claudin-1, claudin-3 and ZO-1 protein in the jejunum of weanling piglets than in 21-d-old suckling piglets（P 〈 0.05）. The abundances of E-cadherin, occludin, ZO-1 and integrin m RNA were positively related to the percentage of PCNA-positive cells.Conclusion： Weaning at 14 d of age induced damage to the intestinal morphology and barrier. While there was an adaptive restoration on d 7 post-weaning, the measured values did not return to the pre-weaning levels, which reflected the impairment of intercellular junctions and Kv channels.

Fecal Microbiota Succession of Piglets from Birth to Post-weaning by 454 Pyrosequencing Analysis

The objective of this study was to describe the fecal microbiota succession of piglets from birth to post-weaning by pyrosequencing. The dominant bacterial phyla were Bacteroidetes, Firmicutes, Proteobacteria, and Fusobacteria, although the composition of the fecal microbiota changed as the piglets grew. Bacteroides, Parabacteroides, Prevotella, Lactobacillus, unclassified Lachnospiraceae, Ruminococcus, Oscillospira, Phascolarctobacterium, and Desulfovibrio were the core genera in the feces of piglets and existed from birth to post-weaning. Bacteroides was the most abundant at birth; however, the proportion of Bacteroides decreased as the piglets aged, while the proportion of Prevotella increased until it became the most abundant genus at the post-weaning stage. Principal coordinate analysis indicated that the microbial communities of piglet fecal samples from birth to post-weaning could be separated into four groups according to the similarity of community composition. These corresponded to time points on day 0 (birth); day 7; days 14, 21, and 28 (pre-weaning); and day 35 (post-weaning). This study suggests that the development of the intestinal microbiota in the piglet is a gradual and sequential process. This methodology establishes a basis for broader studies to investigate the microbiota of the piglet intestinal tract. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

Intermittent suckling with or without comingling of non-littermate piglets before weaning improves piglet performance in the immediate post-weaning period when compared with conventional weaning

Background： In this experiment, intermittent suckling（IS） with or without the co-mingling（Co M） of piglets was studied as a method to stimulate solid feed intake and reduce post-weaning stress.Methods： Three weaning regimes using 30 multiparous sows were compared：（1） conventional weaning（CW）（n = 10 litters）, where piglets had continuous access to the sow until weaning（d 0, farrowing = d-25 relative to weaning）;（2） intermittent suckling（IS）（n = 10 litters）, where piglets were separated from the sow for 8 h/d starting at d-7（relative to weaning）; and（3） intermittent suckling with co-mingling（ISCo）（n = 10 litters） where IS started at d-7 and two litters were housed together during separation and then returned to their original sow. Ad libitum creep feed was available from d-17. At weaning pigs were housed in pens of 11 pigs, 27 pens in total. The ISCo treatment was divided in half to examine effects of different mixing strategies after weaning. Half of the ISCo litters were kept in familiar groups（ISCo F, familiar, n = 4） and the other half were mixed within treatment resulting in groups of unfamiliar pigs（ISCo NF, not familiar, n = 5）, the same as IS（n = 9） and CW（n = 9） treatments.Results： The ISCo piglets ate more creep feed in the week before weaning（P 〈 0.01）, but also showed more aggressive and manipulative behaviour on first day of Co M compared with CW piglets（P 〈 0.05）. IS with or without Co M increased exploratory and play behaviour on the first day of treatment intervention（P 〈 0.001） and increased sleeping behaviour on the last day of treatment intervention compared with CW（P 〈 0.001）. Mixing strategy at weaning had an effect on performance data with the highest growth and feed intake seen in ISCo F pigs 2 to 8 d after weaning（P 〈0.001）. IS and ISCo NF pigs also grew faster and ate more than CW pigs 2 to 8 d after weaning（P 〈 0.001）. Post-weaning injury scores suggested reduced aggression in ISCo as evidenced by reduced redness（skin irritation）（P 〈 0.05）, and a tendency for ISCo to have less scratches than CW（P 〈 0.1）. The IS pigs slept the most and displayed less manipulative behaviours on the day of weaning and plasma haptoglobin levels remained low in IS pigs after weaning（P ≤ 0.01）.Conclusions： Both intermittent suckling techniques improved production indices in the immediate post-weaning period. However, the addition of co-mingling before weaning in combination with grouping familiar pigs together after weaning improved performance in an additive manner.

Methodology and application of Escherichia coli F4 and F18 encoding infection models in post-weaning pigs

The enterotoxigenic Escherichia coli (ETEC) expressing F4 and F18 fimbriae are the two main pathogens associated with post-weaning diarrhea (PWD) in piglets.The growing global concern regarding antimicrobial resistance (AMR) has encouraged research into the development of nutritional and feeding strategies as well as vaccination protocols in order to counteract the PWD due to ETEC.A valid approach to researching effective strategies is to implement piglet in vivo challenge models with ETEC infection.Thus,the proper application and standardization of ETEC F4 and F18 challenge models represent an urgent priority.The current review provides an overview regarding the current piglet ETEC F4 and F18 challenge models;it highlights the key points for setting the challenge protocols and the most important indicators which should be included in research studies to verify the effectiveness of the ETEC challenge.Based on the current review,it is recommended that the setting of the model correctly assesses the choice and preconditioning of pigs,and the timing and dosage of the ETEC inoculation.Furthermore,the evaluation of the ETEC challenge response should include both clinical parameters (such as the occurrence of diarrhea,rectal temperature and bacterial fecal shedding) and biomarkers for the specific expression of ETEC F4/F18 (such as antibody production,specific F4/F18 immunoglobulins (lgs),ETEC F4/F18 fecal enumeration and analysis of the F4/F18 receptors expression in the intestinal brush borders).On the basis of the review,the piglets' response upon F4 or F18 inoculation differed in terms of the timing and intensity of the diarrhea development,on ETEC fecal shedding and in the piglets' immunological antibody response.This information was considered to be relevant to correctly define the experimental protocol,the data recording and the sample collections.Appropriate challenge settings and evaluation of the response parameters will allow future research studies to comply with the replacement,reduction and refinement (3R) approach,and to be able to evaluate the efficiency of a given feeding,nutritional or vaccination intervention in order to combat ETEC infection.

Sow performance in response to natural betaine fed during lactation and post-weaning during summer and non-summer months

Background: Two studies were conducted to evaluate the effects of dietary natural betaine on sow reproductive performance during summer(Exp. 1) and non-summer months(Exp. 2). Treatments were designed as a 2 × 2 factorial arrangement with factors including dietary betaine(0 or 0.2%) and period of supplementation(lactation or post-weaning until 35 days post-insemination). In Exp. 1, 322 and 327 sows and in Exp. 2, 300 and 327 sows representing young(parity 1 and 2) and mature(parity 3 to 6) sows, respectively, were used.Results: In Exp. 1, supplementation of betaine during lactation increased sow body weight losses(-11.95 vs.-14.63 kg;P = 0.024), reduced feed intake(4.12 vs. 4.28 kg/d;P = 0.052), and tended to reduce percentage of no-value pigs(P = 0.071). Betaine fed post-weaning reduced weaning-to-estrus interval(5.75 vs. 6.68 days;P = 0.054) and farrowing rate(86.74% vs. 91.36%;P = 0.060), regardless of parity group. Post-hoc analysis with sows clustered into 3 parity groups(1, 2 and 3, and 4+) indicated that betaine fed in lactation to parity 4+ sows(P = 0.026) and betaine fed post-weaning to parity 1 sows increased the number of pigs born in the subsequent cycle(P ≤ 0.05). In Exp. 2, betaine fed during lactation tended to reduce the weaning-to-estrus interval(6.64 vs. 7.50 days;P = 0.077) and farrowing rate(88.23% vs.83.54%;P = 0.089), regardless of parity group. Feeding betaine post-weaning reduced number of pigs born(13.00 vs.13.64;P = 0.04) and pigs born alive(12.30 vs. 12.82;P = 0.075), regardless of parity group.Conclusions: Using 0.2% betaine during the non-summer months did not benefit sow performance. During the summer, betaine supplementation in lactation increased subsequent litter size in parity 4+ sows. Betaine fed during the post-weaning period reduced the wean-to-estrus interval and farrowing rate, increased total number of pigs born for parity 1 sows and reduced total number of pigs born to parity 4+ sows. Further research is needed to determine if the detrimental effects on feed intake and farrowing rate may be correlated and depend on dietary betaine level.

Dietary supplementation of benzoic acid and essential oils combination enhances intestinal resilience against LPS stimulation in weaned piglets

Background The benefits of combining benzoic acid and essential oils(BAO)to mitigate intestinal impairment during the weaning process have been well established,while the detailed underlying mechanism has not been fully elucidated.Previous research has primarily focused on the reparative effects of BAO on intestinal injury,while neglecting its potential in enhancing intestinal stress resistance.Methods In this study,we investigated the pre-protective effect of BAO against LPS-induced stress using a modified experimental procedure.Piglets were pre-supplemented with BAO for 14 d,followed by a challenge with LPS or saline to collect blood and intestinal samples.Results Our findings demonstrated that BAO supplementation led to significant improvements in piglets’final weight,average daily gain,and feed intake/body gain ratio.Additionally,BAO supplementation positively influenced the composition of intestinal microbiota,increasing beneficial Actinobacteriota and Alloprevotella while reducing harmful Desulfobacterota,Prevotella and Oscillospira.Furthermore,BAO supplementation effectively mitigated oxidative disturbances and inflammatory responses induced by acute LPS challenge.This was evidenced by elevated levels of T-AOC,SOD,and GSH,as well as decreased levels of MDA,TNF-α,and IL-6 in the plasma.Moreover,piglets subjected to LPS challenge and pre-supplemented with BAO exhibited significant improvements in intestinal morphological structure and enhanced integrity,as indicated by restored expression levels of Occludin and Claudin-1 compared to the non-supplemented counterparts.Further analysis revealed that BAO supplementation enhanced the jejunal antioxidative capacity by increasing GSH-Px levels and decreasing MDA levels under the LPS challenge and stimulated the activation of the Nrf2 signaling pathway.Additionally,the reduction of TLR4/NF-κB/MAPK signaling pathways activation and proinflammatory factor were also observed in the jejunal of those piglets fed with BAO.Conclusions In summary,our study demonstrates that pre-supplementation of BAO enhances the anti-stress capacity of weaned piglets by improving intestinal microbiota composition,reinforcing the intestinal barrier,and enhancing antioxidative and anti-inflammatory capabilities.These effects are closely associated with the activation of Nrf2 and TLR4/NF-κB/MAPK signaling pathways.

The protective role of prebiotics and probiotics on diarrhea and gut damage in the rotavirus-infected piglets

Rotavirus is one of the pathogenic causes that induce diarrhea in young animals, especially piglets, worldwide. However, nowadays, there is no specific drug available to treat the disease, and the related vaccines have no obvious efficiency in some countries. Via analyzing the pathogenesis of rotavirus, it inducing diarrhea is mainly due to disturb enteric nervous system, destroy gut mucosal integrity, induce intracellular electrolyte imbalance, and impair gut microbiota and immunity. Many studies have already proved that prebiotics and probiotics can mitigate the damage and diarrhea induced by rotavirus infection in hosts. Based on these, the current review summarizes and discusses the effects and mechanisms of prebiotics and probiotics on rotavirus-induced diarrhea in piglets. This information will highlight the basis for the swine production utilization of prebiotics and probiotics in the prevention or treatment of rotavirus infection in the future.

Dietary supplementation of laminarin improves the reproductive performance of sows and the growth of suckling piglets

Background Maternal nutrition is essential in keeping a highly efficient production system in the pig industry.Laminarin has been shown to improve antioxidant capacity,reduce the inflammatory response,and favor the homeostasis of intestinal microbiota.However,the effect of dietary supplementation of laminarin on the reproductive performance of sows and the growth of suckling offspring remains unknown.Methods A total of 40 Landrace×Yorkshire multiparous sows on d 85 of gestation,similar in age,body weight(BW),parity and reproductive performance,were randomly divided into four dietary treatments with 10 sows per treatment,receiving a control diet(basal pregnancy or lactating diets)and a basal diet supplemented with 0.025%,0.05%and 0.10%laminarin,respectively.The experiment lasted from d 85 of gestation to d 21 of lactation.Results Laminarin supplementation linearly increased number born alive per litter(P=0.03),average daily feed intake(ADFI,P<0.01),and total milk yield of sows during the lactation of 1–21 d(P=0.02).Furthermore,maternal laminarin supplementation increased the average daily gain(ADG)of piglets while tending to reduce the culling and death rate before weaning.In addition,alterations to the composition of colostrum and milk,as well as to serum inflammatory cytokines and immunoglobulins of sows were observed.The fecal microbiota profile of sows supported the improvement of reproductive performance in sows and the growth performance in suckling offspring.Conclusions Dietary supplementation of laminarin during late pregnancy and lactation could significantly improve reproductive performance of sows and growth performance of piglets.

Effects of Immunological Stress on Immune Response in Different Breeds of Piglets

[ Objective] The research aimed to explore effects of an immunological stress on immune response in different breeds of piglets （ Lulai pig, Laiwu pig and Yorkshire pig）. [Method] All the 12 weaning pigs （Lulai pig, Laiwu pig and Yorkshire pig） weighing （12.6 ±0.5） kg were used in a 2 x3 factorial design. The main factors consisted of immunological challenge （ LPS or saline） and breeds （ Lulai pig, Laiwu pig and Yorkshire pig）. On Day 1, six piglets of each breed were injected with LPS at the usage of 200 μg/kg BW or an equivalent amount of sterile saline, and in jected classical swine fever vaccine at the same time. Blood sample were collected on Day 2, 7 and 14 post injection to analyze the blood lympho cyte proliferation. The levels of antibodies against classical swine fever were tested on Day 1 prior to injection and on Day 7 and 14 post injection. [ Result] On Day 2 after injection, the lymphocyte transformation rate of piglets injected with LPS were significantly （P〈O. 01 ） increased compared with piglets injected with saline. The lymphocyte transformation rate of Laiwu piglets was significant higher than that of Yorkshire piglets （ P 〈 0.05）. Effects of immunological stress on the level of antibodies against classical swine fever were not significantly different among different breeds of pig lets. [ Conclusion] LPS can effectively stimulate cellular immunity response in different breeds of piglets, and the immune response ability is different among various breeds of piglets.

Effects of the kinetic pattern of dietary glucose release on nitrogen utilization, the portal amino acid profile, and nutrient transporter expression in intestinal enterocytes in piglets

Background Promoting the synchronization of glucose and amino acid release in the digestive tract of pigs could effectively improve dietary nitrogen utilization.The rational allocation of dietary starch sources and the exploration of appropriate dietary glucose release kinetics may promote the dynamic balance of dietary glucose and amino acid supplies.However,research on the effects of diets with different glucose release kinetic profiles on amino acid absorption and portal amino acid appearance in piglets is limited.This study aimed to investigate the effects of the kinetic pattern of dietary glucose release on nitrogen utilization,the portal amino acid profile,and nutrient transporter expression in intestinal enterocytes in piglets.Methods Sixty-four barrows(15.00±1.12 kg)were randomly allotted to 4 groups and fed diets formulated with starch from corn,corn/barley,corn/sorghum,or corn/cassava combinations(diets were coded A,B,C,or D respectively).Protein retention,the concentrations of portal amino acid and glucose,and the relative expression of amino acid and glucose transporter m RNAs were investigated.In vitro digestion was used to compare the dietary glucose release profiles.Results Four piglet diets with different glucose release kinetics were constructed by adjusting starch sources.The in vivo appearance dynamics of portal glucose were consistent with those of in vitro dietary glucose release kinetics.Total nitrogen excretion was reduced in the piglets in group B,while apparent nitrogen digestibility and nitrogen retention increased(P<0.05).Regardless of the time(2 h or 4 h after morning feeding),the portal total free amino acids content and contents of some individual amino acids(Thr,Glu,Gly,Ala,and Ile)of the piglets in group B were significantly higher than those in groups A,C,and D(P<0.05).Cluster analysis showed that different glucose release kinetic patterns resulted in different portal amino acid patterns in piglets,which decreased gradually with the extension of feeding time.The portal His/Phe,Pro/Glu,Leu/Val,Lys/Met,Tyr/Ile and Ala/Gly appeared higher similarity among the diet treatments.In the anterior jejunum,the glucose transporter SGLT1 was significantly positively correlated with the amino acid transporters B0AT1,EAAC1,and CAT1.Conclusions Rational allocation of starch resources could regulate dietary glucose release kinetics.In the present study,group B(corn/barley)diet exhibited a better glucose release kinetic pattern than the other groups,which could affect the portal amino acid contents and patterns by regulating the expression of amino acid transporters in the small intestine,thereby promoting nitrogen deposition in the body,and improving the utilization efficiency of dietary nitrogen.

All-trans retinoic acid alleviates transmissible gastroenteritis virus-induced intestinal inflammation and barrier dysfunction in weaned piglets

Background Transmissible gastroenteritis virus(TGEV)is one of the main pathogens causing severe diarrhea of pig-lets.The pathogenesis of TGEV is closely related to intestinal inflammation.All-trans retinoic acid(ATRA)is the main active metabolite of vitamin A,which has immunomodulatory and anti-inflammatory properties.However,it is unclear whether ATRA can alleviate TGEV-induced intestinal inflammation and barrier dysfunction in piglets.This study aimed to investigate the effects of ATRA on growth performance,diarrhea,intestinal inflammation and intesti-nal barrier integrity of TGEV-challenged piglets.Methods In a 19-d study,32 weaned piglets were randomly divided into 4 treatments:Control group(basal diet),TGEV group(basal diet+TGEV challenge),TGEV+ATRA5 group(basal diet+5 mg/d ATRA+TGEV challenge)and TGEV+ATRA15 group(basal diet+15 mg/d ATRA+TGEV challenge).On d 14,piglets were orally administered TGEV or the sterile medium.Results Feeding piglets with 5 and 15 mg/d ATRA alleviated the growth inhibition and diarrhea induced by TGEV(P<0.05).Feeding piglets with 5 and 15 mg/d ATRA also inhibited the increase of serum diamine oxidase(DAO)activ-ity and the decrease of occludin and claudin-1 protein levels in jejunal mucosa induced by TGEV,and maintained intestinal barrier integrity(P<0.05).Meanwhile,5 mg/d ATRA feeding increased the sucrase activity and the expres-sions of nutrient transporter related genes(GLUT2 and SLC7A1)in jejunal mucosa of TGEV-challenged piglets(P<0.05).Furthermore,5 mg/d ATRA feeding attenuated TGEV-induced intestinal inflammatory response by inhibit-ing the release of interleukin(IL)-1β,IL-8 and tumor necrosis factor-α(TNF-α),and promoting the secretion of IL-10 and secretory immunoglobulin A(sIgA)(P<0.05).Feeding 5 mg/d ATRA also down-regulated the expressions of Toll-like receptors and RIG-I like receptors signaling pathway related genes(TLR3,TLR4,RIG-I,MyD88,TRIF and MAVS)and the phosphorylation level of nuclear factor-κB-p65(NF-κB p65),and up-regulated the inhibitor kappa B alpha(IκBα)protein level in jejunal mucosa of TGEV-challenged piglets(P<0.05).Conclusions ATRA alleviated TGEV-induced intestinal barrier damage by inhibiting inflammatory response,thus improving the growth performance and inhibiting diarrhea of piglets.The mechanism was associated with the inhibi-tion of NF-κB signaling pathway mediated by TLR3,TLR4 and RIG-I.

Composition,function,and timing:exploring the early‑life gut microbiota in piglets for probiotic interventions

Background The establishment of a robust gut microbiota in piglets during their early developmental stage holds the potential for long-term advantageous effects.However,the optimal timeframe for introducing probiotics to achieve this outcome remains uncertain.Results In the context of this investigation,we conducted a longitudinal assessment of the fecal microbiota of 63 piglets at three distinct pre-weaning time points.Simultaneously,we gathered vaginal and fecal samples from 23 sows.Employing 16S rRNA gene and metagenomic sequencing methodologies,we conducted a comprehensive analysis of the fluctuation patterns in microbial composition,functional capacity,interaction networks,and colonization resistance within the gut microbiota of piglets.As the piglets progressed in age,discernible modifications in intestinal microbial diversity,composition,and function were observed.A source-tracking analysis unveiled the pivotal role of fecal and vaginal microbiota derived from sows in populating the gut microbiota of neonatal piglets.By D21,the microbial interaction network displayed a more concise and efficient configuration,accompanied by enhanced colonization resistance relative to the other two time points.Moreover,we identified three strains of Ruminococcus sp.at D10 as potential candidates for improving piglets’weight gain during the weaning phase.Conclusions The findings of this study propose that D10 represents the most opportune juncture for the introduction of external probiotic interventions during the early stages of piglet development.This investigation augments our comprehension of the microbiota dynamics in early-life of piglets and offers valuable insights for guiding forthcoming probiotic interventions.

Effects of early postnatal gastric and colonic microbiota transplantation on piglet gut health

Background Diarrhea is a major cause of reduced growth and mortality in piglets during the suckling and weaning periods and poses a major threat to the global pig industry.Diarrhea and gut dysbiosis may in part be prevented via improved early postnatal microbial colonization of the gut.To secure better postnatal gut colonization,we hypothesized that transplantation of colonic or gastric content from healthy donors to newborn recipients would prevent diarrhea in the recipients in the post-weaning period.Our objective was to examine the impact of transplanting colonic or gastric content on health and growth parameters and paraclinical parameters in recipient single-housed piglets exposed to a weaning transition and challenged with enterotoxigenic Escherichia coli(ETEC).Methods Seventy-two 1-day-old piglets were randomized to four groups:colonic microbiota transplantation(CMT,n=18),colonic content filtrate transplantation(CcFT,n=18),gastric microbiota transplantation(GMT,n=18),or saline(CON,n=18).Inoculations were given on d 2 and 3 of life,and all piglets were milk-fed until weaning(d 20)and shortly after challenged with ETEC(d 24).We assessed growth,diarrhea prevalence,ETEC concentration,organ weight,blood parameters,small intestinal morphology and histology,gut mucosal function,and microbiota composition and diversity.Results Episodes of diarrhea were seen in all groups during both the milk-and the solid-feeding phase,possibly due to stress associated with single housing.However,CcFT showed lower diarrhea prevalence on d 27,28,and 29 compared to CON(all P<0.05).CcFT also showed a lower ETEC prevalence on d 27(P<0.05).CMT showed a higher alpha diversity and a difference in beta diversity compared to CON(P<0.05).Growth and other paraclinical endpoints were similar across groups.Conclusion In conclusion,only CcFT reduced ETEC-related post-weaning diarrhea.However,the protective effect was marginal,suggesting that higher doses,more effective modalities of administration,longer treatment periods,and better donor quality should be explored by future research to optimize the protective effects of transplantation.

Effects of Mycotoxin from Maize on Immune Response of Vaccine for Piglets

[Objective] The aim of this study was to investigate the effects of mycotoxin from moldy maize on immune response of piglets.[Method] ELISA method was used to determine the content of Aflatoxin B1 and ochratoxin A in maize; after the piglets were fed with the moldy maize,the corresponding antibody titers in the serums of piglets were measured.[Result] Antibody levels of tested group were obvious lower than that of the control,while the histological section of immune organs also suggested that mycotoxin could significantly inhibit the immune response of piglets.[Conclusion] Mycotoxin in maize had important effects on the internal organs and immune response of piglets.

Proteomic-Level Responses of Early-Weaned Piglets to Dietary Arginine Supplementation

Dietary arginine supplementation enhances the immune status and protein synthesis in early-weaned pigs. However, the underlying mechanisms remain largely unknown. To investigate how arginine affects the expression of key proteins that regulate growth and nutrient transport of jejunum, a total of 12 healthy piglets （21 day-old, similar body weight, Landrace x Yorkshire） delivered by four sows were randomly divided into two groups. Piglets in the test group were reared with feed supplemented L-arginine at a concentration of 6.0 g/kg, while piglets in the control group were fed with feed supplemented L-alanine at a concentration of 12.3 g/kg （isonitrogenous control）. After 7 d, jejunum mucosae was collected and analyzed with the 2-D PAGE MS technology. Compared with the control pigs, arginine decreased the levels of proteins that regulate the protein syn- thesis, intermediary metabolism and tissue growth （ similar to anterior gradient 2 homolog, cyclophilin_ABHJike, hypothetical protein FLJ39502 and tetratrioopeptide repeat domain 16, similar to KIAA0156, mitechondrial ATP synthase, hydrion transporting F1 complex, beta subunit and alpha-tu- bulin ubiquitous isoform 19, prolyl 4-hydroxylase, beta subunit precursor）. In addition, arginine increased the levels of proteins that are involved in proteolysis and immune response （ PGAM1, T cell receptor beta variable 20, membrane steroid binding protein, similar to myomesin-1, and chain A, structure of pig muscle Pgk complexed with MgATP）. Therefore, arginine influences the immune response and protein synthesis mechanisms as well as improves eady weaned stress syndrome of piglets.

Effects of Feed-grade Proteinase on the Production Performance of Piglets

In this study, feed-grade proteinase was added into conventional diets of three-line crossbred （Duroc x Landrace x Large White） piglets, to investigate the effects of feed-grade proteinase on anti-diarrhea capacity, daily weight gain, feed intake and feed conversion ratio of piglets. The results showed that adding feed-grade proteinase in diets enhanced anti-diarrhea capacity of piglets and improved signifi- cantly production performance and breeding efficiency of piglets. This study provided the reference for rational utilization of feed-grade proteinase in actual production.

16S rRNA Gene-Based Analysis of Ileal Bacterial Community and Phylogeny in Nursing and Weaned Piglets

Weaning of piglets is generally considered as a stressor which changes intestinal ecosystem and leads to clinical implications. Microbiota inhabiting in small intestine （especially ileum） are assumed to promote health, but their functional properties are yet poody dascdbed. As indicated by the 16S rRNA gene sequences of ileal micrebiota in nursing piglets （at the age of 21 and 28 d） and 28-day-old weaned piglets （weaned at 21 d of age）, the microbiota were mainly comprised of gram-positive bacteria. There were 40 operational taxonomic units （OTUs） （from 171 clones） in the ileum of nursing piglets aged 21 d, 61 OTUs （from 194 clones） in the ileum of nursing piglets aged 28 d, and 56 OTUs （from 171 clones） in the ileum of weaned piglets aged 28 d. The flea of nursing piglets aged 21 d were dominantly occupied by Lactobacilli （87.7%） as well as Streptococ cus （ 3.5 % ）. Lactobacillus amy/ovorus （41.5 % ）, Lactobaci/lus sp. （ 19.3 % ）, Lactobaci/lus reuteri （ 12.3 % ）, Lactobacillus salivarius （ 9.4 % ） and L. mucosae （4.7%） were the predominant species among Lactobacil/L Similar results were obtained in the nursing piglets at 28 d of age ex- cept that Lactobaci/li decreased to 71.1% and Streptococcus increased to 21.1% significantly. Lactobacillus （52.0%） and Streptococcus （26.3%） were the two major groups in the ileum of weaned piglets aged 28 d. Lactobacillus amylovorus （31.6%） and Lactobaci/lus reuteri （ 16.4% ） was the two most important species in Lactobacillus. Therefore, Lactobacilli were predominant in the ileum of nursing and weaned piglets, and they had the highest diversity, followed by Streptococcus. The diversity of ileal microbiota was not different remarkably between the nursing piglets and the weaned piglets, but the composition changed significantly. These findings are helpful to understand ileal bacterial ecophysiology and further develop nutritional regimes to prevent or counteract complications during the weaning transition.