Effect of PRRSV stability on productive parameters in breeding herds of a swine large integrated group in Spain

BACKGROUND

In breeding herds, porcine reproductive and respiratory syndrome (PRRS) clinically manifests as increased abortions, number of stillbirths, and pre-weaning mortality, and as a direct consequence, results in a decrease of the number of piglets weaned per sow per year. Breeding farm classification according the PRRS virus (PRRSV) status (unstable or stable) is a key control strategy for this disease. The aim of this study was to evaluate the production improvement related to achieving a PRRSV stable status in breeding herds in Spain. For this purpose, epidemiological and productivity data were collected from a systematic PRRSV monitoring program in 35 breeding herds from a large integrated swine group in Spain. A comparative statistical analysis was conducted using four key production indicators (KPI) between different PRRSV status and a generalized linear mixed model: weekly abortions/1000 sows (ABTHS), born-alive rate (BAR), pre-weaning mortality rate (PWMR), and number of weaned piglets per 1000 sows (WPTHS).

RESULTS

From the 35 monitored farms during a total period of 58 weeks, we collected 49 to 58 weeks of production data and PRRSV classification status for each study farm. This represented a total of 1997 (741 unstable and 1256 stable) weekly data collected that was eligible for the KPI comparative study. PRRSV stability was associated with significant improvement in BAR (+ 1.10 %, p < 0.001), PWMR (-0.88 %, p < 0.002) and WPTHS (+ 24.52, p < 0.0001).

CONCLUSIONS

These results demonstrate for the first time the improved production due to achieving PRRSV stability in breeding herds under field conditions in a European country. Increased number of born-alive piglets and a reduction of piglet pre-weaning mortality represents an increase of 1.28 weaned piglets per sow per year if PRRSV stability was achieved and maintained for one-year period in a breeding farm.

Supplementation of a β-mannanase enzyme reduces post-weaning diarrhea and antibiotic use in piglets on an alternative diet with additional soybean meal

Enzyme supplementation with a β-mannanase to degrade β-mannan fibers present in the diet has been shown to restore and improve performance in swine. The current study was conducted on a farm which had historical episodes of post-weaning diarrhea. In total, 896 newly weaned piglets were enrolled in two consecutive trials. Each trial consisted of 32 pens of 14 piglets housed in one large post-weaning compartment. Piglets at the same feeder were randomly assigned to the two treatment groups. The study compared the performance of post-weaned piglets fed either a commercial 3-phase nursery diet (Control) or an adapted diet supplemented with a β-mannanase (Hemicell HT; Elanco) (Enzyme), with some of the more expensive proteins replaced by soy bean meal in phase 1 and 2, and net energy (NE) content reduced by 65 kcal/kg in phase 3. All data analyses were performed using R version 3.6.3 (R Core Team, 2020). All tests were performed at the 5% level of significance. When multiple testing was involved, the nominal 5% Familywise Error Rate (FWER) was used. The study showed similar performance on the alternative diet with β-mannanase and the common commercial diets (P >  0.05). However, the Enzyme treated group had a significantly better general clinical score. Moreover, the number of individual treatments was a factor exp(0.69441) or 2 (CI 95% [1.46; 2.74]) higher (P < 0.001) in the Control group as compared to the Enzyme treated group. The number of treated animals was a factor exp(0.62861) or 1.87 (CI 95% [1.43; 2.53]) higher (P < 0.001) and the number of pigs with a repeated treatment was a factor exp(0.9293) or 2.53 (CI 95% [1.26; 5.09]) higher (P = 0.009) in the Control group as compared to the Enzyme treated group. In total, 7 (1.56%) piglets died in the Control group, whereas only 2 (0.45%) piglets died in the Enzyme treated group. The hazard ratio for mortality in the Control group relative to the Enzyme treated group was and estimated as 1.74 (CI 95% [0.51; 5.96]). Thus, the Control group had a non-significantly (P = 0.375) increased mortality. In conclusion, the results suggest that the use of an exogenous heat-tolerant β-mannanase allowed reduced levels of expensive protein sources to be used in the first two diets fed post-weaning, and 65 kcal/kg lower net energy content to be used in the third diet without adverse effects on intestinal health or overall performance. In fact, the occurrence of PWD and number of individual treatments during the post-weaning period were significantly reduced on the β-mannanase supplemented diets.

The role of liver metabolism in compensatory-growth piglets induced by protein restriction and subsequent protein realimentation

The aim of this work was to study the role of hepatic metabolism of compensatory growth in piglets induced by protein restriction and subsequent protein realimentation. Thirty-six weaned piglets were randomly distributed in a control group and a treatment group. The control group piglets were fed with a normal protein level diet (18.83% CP) for the entire experimental period (day 1-28). The treatment group piglets were fed with a protein-restriction diet (13.05% CP) for day 1 to day 14, and the diet was restored to normal protein level diet for day 15 to day 28. RNA-seq is used to analyze samples of liver metabolism on day 14 and day 28, respectively. Hepatic RNA-sequencing analysis revealed that some KEGG signaling pathways involved in glycolipid metabolism (eg, "AMPK signaling pathway," "insulin signaling pathway," and "glycolysis or gluconeogenesis") were significantly enriched on day 14 and day 28. On day 14, protein restriction promoted hepatic lipogenesis by increasing the genes expression level of ACACA, FASN, GAPM, and SREBP1C, decreasing protein phosphorylation levels of AMPKɑ and ACC in AMPK signaling pathway. In contrast, on day 28, protein realimentation promoted hepatic gluconeogenesis by increasing the concentration of G6Pase and PEPCK, decreasing protein phosphorylation levels of IRS1, Akt, and FoXO1 in insulin signaling pathway. In addition, protein realimentation activated the GH-IGF1 axis between the liver and skeletal muscle. Overall, these findings revealed the importance of liver metabolism in achieving compensatory growth.

Alterations in the diversity and composition of gut microbiota in weaned piglets infected with Balantioides coli

Balantioides coli is a ciliated parasite that can cause diarrhea when inhabiting the colon and cecum of pigs and humans. However, information regarding the changes in structure and composition of the gut microbiome in piglets infected with B. coli remains scarce. In this study, 16S rDNA amplicon sequencing was conducted on fecal samples from both B. coli-positive piglets with diarrhea and B. coli-negative piglets without diarrhea. The results showed that Firmicutes and Bacteroidetes were the major phyla in the two groups, and the relative abundance of the phylum Firmicutes, including Ruminococcaceae and Clostridiaceae, was significantly lower in the B. coli-positive samples than in the B. coli-negative ones (p < 0.05). Compared with B. coli-negative samples, Alloprevotella and Faecalibacterium showed distinctly higher relative abundances (p < 0.05) in the B. coli-positive samples, and the abundances of some potential pathogenic bacteria, including Escherichia-Shigella and Campylobacter, were positively correlated with B. coli infection and diarrhea of weaned piglets. In addition, there were statistically significant differences in fecal microbiota diversity and abundances of predicted functional genes between B. coli-colonized and B. coli-negative samples (p <  0.05). Taken together, these findings suggest that there were significant differences in the bacterial community composition, diversity, and functions between the B. coli-positive and B. coli-negative piglets, and the colonization by B. coli may be associated with the dysbiosis of gut microbiota structure in weaned piglets.

Multi-omics profiling highlights lipid metabolism alterations in pigs fed low-dose antibiotics

Background

In order to study the relations of hepatocellular functions, weight gain and metabolic imbalance caused by low-dose antibiotics (LDA) via epigenetic regulation of gene transcription, 32 weaned piglets were employed as animal models and randomly allocated into two groups with diets supplemented with 0 or LDA (chlorotetracycline and virginiamycin).

Results

During the 4 weeks of the experiment, LDA showed a clear growth-promoting effect, which was exemplified by the significantly elevated body weight and average daily gain. Promoter methylome profiling using liquid hybridization capture-based bisulfite sequencing (LHC-BS) indicated that most of the 745 differential methylation regions (DMRs) were hypermethylated in the LDA group. Several DMRs were significantly enriched in genes related with fatty acids metabolic pathways, such as FABP1 and PCK1. In addition, 71 differentially expressed genes (DEGs) were obtained by strand-specific transcriptome analysis of liver tissues, including ALOX15, CXCL10 and NNMT, which are three key DEGs that function in lipid metabolism and immunity and which had highly elevated expression in the LDA group. In accordance with these molecular changes, the lipidome analyses of serum by LC-MS identified 38 significantly differential lipids, most of which were downregulated in the LDA group.

Conclusions

Our results indicate that LDA could induce epigenetic and transcriptional changes of key genes and lead to enhanced efficiency of lipid metabolism in the liver.

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 post-weaning diarrhea without altering growth performance in weaned piglets, which might be achieved by improving intestinal barrier integrity and function.

Dietary fermented soybean meal replacement alleviates diarrhea in weaned piglets challenged with enterotoxigenic Escherichia coli K88 by modulating inflammatory cytokine levels and cecal microbiota composition

BACKGROUND

Impaired gut microbiota leads to pathogenic bacteria infection, pro-inflammatory response and post-weaning diarrhea. Enterotoxigenic Escherichia coli (ETEC) K88 is a major cause of post-weaning diarrhea in weaned piglets. Fermented soybean meal (FSBM) could relieve diarrhea, alleviate inflammatory response, and modulate gut microbiota of weaned piglets. We used ETEC K88-challenged weaned piglet model to investigate the effects of FSBM on the growth performance, inflammatory response and cecal microbiota. Twenty-four crossbred piglets (6.8 ± 0.5 kg; 21 ± 2 days of age) were allotted into 2 treatment fed the diets with or without FSBM (6% at the expense of soybean meal). Six weaned piglets in each diet treatment were challenged by ETEC K88 (1 × 109 CFU/piglets) on day 15. The experimental period lasted for 20 days.

RESULTS

The ETEC K88 challenge decreased (p < 0.05) fecal consistency and plasma interleukin-10 (IL-10) concentration, while increased (p < 0.05) average daily feed intake (ADFI) and plasma tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin 6 (IL-6) concentrations. After ETEC K88 challenge, dietary FSBM replacement increased (p < 0.05) final body weight (BW), average daily gain (ADG), ADFI, and fecal consistency, but decreased feed conversion ratio (FCR). The plasma IL-10 concentration of weaned piglets fed FSBM was higher (p < 0.05), while IL-1β, IL-6 and TNF-α concentrations were lower (p < 0.05). Dietary FSBM replacement attenuated the increase of plasma TNF-α concentration and the decrease of ADG induced by ETEC K88 challenge (p < 0.05). High-throughput sequencing of 16S rRNA gene V4 region of cecal microbiota revealed that ETEC K88 challenge increased (p < 0.05) Campylobacter relative abundance on genus level. Dietary FSBM replacement resulted in higher (p < 0.05) relative abundances of Bacteroidetes and Prevotellaceae_NK3B31_group, and lower (p < 0.05) relative abundances of Proteobacteria and Actinobacillus. Furthermore, dietary FSBM replacement relieved the increase of Escherichia-Shigella relative abundance in weaned piglets challenged by ETEC K88 (p < 0.05).

CONCLUSIONS

Dietary FSBM replacement improved growth performance and alleviated the diarrhea of weaned piglets challenged with ETEC K88, which could be due to modulation of cecal microbiota composition and down-regulation of inflammatory cytokines production.

Effects of dose and duration of dietary copper administration on hepatic lipid peroxidation and ultrastructure alteration in piglets' model

BACKGROUND

Copper is an essential microelement for animals and has been used at pharmacological doses in weaned piglets to improve growth performance. However, it also induces systemic oxidative stress after short-term feeding. The aim of this study was to investigate the effects of dose and duration of dietary copper on lipid peroxidation and oxidative stress status in model of weaned piglets.

METHODS

A total of 48 crossbred piglets (weaned at 21d, weight ∼8.2 kg) were randomly assigned into 4 groups of 12 in each. The control group and 3 treatment groups fed with basal diet supplemented with 20, 100 and 200 mg/kg copper as copper sulfate for 3 and 6 weeks, respectively.

RESULTS

Dietary copper supplementation significantly affected the activities of ALP, LDH, LIPC and the levels of Ca and TG in serum as well as the copper and zinc deposition in liver. Increased MDA concentrations, and decreased GPX, CP and CAT concentrations in serum were found in 0, 100 and 200 mg Cu/kg diet groups at 3 weeks post weaning. Hepatic lipid peroxidation was also induced in these groups indicated from hepatic SOD1, GPX1, CAT, CP, MT1A and MT2A transcriptional levels. Those adverse symptoms were alleviative at 6 weeks post weaning. The hepatic Cu and Zn concentrations, serum MDA concentrations, and serum CAT and GPX activities were significantly correlated with Actinobacillus, Lactobacillus, Sarcina, Helicobacter, Campylobacterales, which could affect the intestinal health further.

CONCLUSION

These results indicated that copper deficiency or over supplementation would affect the systemic lipid peroxidation. These adverse changes were not observed when the dietary copper concentration at 20 mg Cu/kg diet. The results suggested the appropriate dietary copper concentration is around 20 mg Cu/kg diet, and its range might be much stricter than we thought.

Toxicity of glyphosate in feed for weanling piglets and the mechanism of glyphosate detoxification by the liver nuclear receptor CAR/PXR pathway

Glyphosate (GLP), the most widely used and productive pesticide worldwide, which safety and reliability gradually become a social concern. It is important to explore the toxic of GLP on the limitation level by governments on piglets and the potential role of hepatic CAR/PXR and Keap1-Nrf2 pathways in low levels of glyphosate detoxification. Compared with the control group, the production performance and organ index of GLP group showed no significant change. However, the liver GLP residue of 40 mg/kg group was significantly higher than the control group. We also found that the activity of ALP increased linearly and DBIL content increased quadratically. Furthermore, GLP could significantly increase SOD and GSH-Px and decrease T-AOC and CAT activities and significantly increase MDA and H2O2 contents (P < 0.05); however, the genes expression of Keap1/Nrf2 pathway was not affected. Gene expression of CAR/PXR pathway showed that GLP could significantly stimulate the expression of CAR, but it could not affect the expression of phase Ⅰ (CYP1A1, CYP1A2, CYP2E1, CYP2A19, CYP3A29), phase Ⅱ (UGT1A6, GSTA1, GSTA2) detoxification enzymes and transporters (MDR1, MRP2, P-gp). Our study showed that although 10-40 mg/kg GLP would inevitably cause some liver damage and dysfunction, it can self-alleviating the toxic effect of GLP.

Effect of glucose, soya oil and glutamine on protein expression and mammalian target of rapamycin complex 1 pathway of jejunal crypt enterocytes in weaned piglets

The present study was conducted to evaluate the effects of glucose, soya oil or glutamine on jejunal morphology, protein metabolism and protein expression of the mammalian target of rapamycin complex 1 (mTORC1) signalling pathway in jejunal villus or crypt compartment of piglets. Forty-two 21 d-weaned piglets were randomly allotted to one of the three isoenergetic diets formulated with glucose, soya oil or glutamine for 28 d. On day 14 or 28, the proteins in crypt enterocytes were analysed with isobaric tags for relative and absolute quantification and proteins involved in mTORC1 signalling pathway in villus or crypt compartment cells were determined by Western blotting. Our results showed no significant differences (P > 0·05) in jejunal morphology among the three treatments on day 14 or 28. The differentially expressed proteins mainly took part in a few network pathways, including antimicrobial or inflammatory response, cell death and survival, digestive system development and function and carbohydrate metabolism. On day 14 or 28, there were higher protein expression of eukaryotic initiation factor-4E binding protein-1 in jejunal crypt compartment of piglets supplemented with glucose or glutamine compared with soya oil. On day 28, higher protein expression of phosphor-mTOR in crypt compartment was observed in piglets supplemented with glucose compared with the soya oil. In conclusion, the isoenergetic glucose, soya oil or glutamine did not affect the jejunal morphology of piglets; however, they had different effects on the protein metabolism in crypt compartment. Compared with soya oil, glucose or glutamine may be better energy supplies for enterocytes in jejunal crypt compartment.

Dietary garcinol supplementation improves diarrhea and intestinal barrier function associated with its modulation of gut microbiota in weaned piglets

Background

The effects of dietary garcinol on diarrhea and intestinal barrier function associated with its modulation of gut microbiota in weaned piglets were investigated.

Method

One hundred forty four weaned piglets (Duroc × Yorkshire × Landrace) from 16 pens (9 piglets per pen) were randomly divided into four treatment groups: controls (CON) or those supplemented with 200 mg/kg (LOW), 400 mg/kg (MID), or 600 mg/kg (HIGH) diet garcinol. After 14-day trial, three piglets per pen were chosen to collect plasma, intestinal tissue and colonic digesta samples.

Results

We demonstrated for the first time that garcinol promoted growth performance, as increased average daily feed intake (ADFI) and decreased feed/gain ratio (F/G); and reduced diarrhea incidence (P < 0.05); and strengthened antioxidant capacity, as an increased antioxidative index (P < 0.05). Additionally, garcinol ameliorated intestinal barrier dysfunction, as an increased villus height to crypt depth ratio, increased zonula occludens protein 1 (ZO-1), occludin and claudin-1 expression in the jejunum and ileum (P < 0.05), and decreased intestinal permeability (P < 0.05); and reduced inflammation, as decreased cytokine interleukin (IL)-6, IL-10, IL-1β and tumor necrosis factor-α (TNF-α) levels in the mucosa of the jejunum and ileum, and NF-κB p65 translocation (P < 0.05). Moreover, garcinol inhibited the growth of most harmful bacteria in the gut, especially Escherichia coli, and increased the growth of the beneficial bacteria Lactobacillus.

Conclusion

This work provides a fundamental basis for the future development of garcinol-functional food use for improving diarrhea and intestinal barrier function in weaned piglets and for understanding the biological effects of garcinol and its potential as a functional feed additive.

Effect of fosfomycin, Cynara scolymus extract, deoxynivalenol and their combinations on intestinal health of weaned piglets

Weaning is a challenging stage of pig farming. Animals undergo environmental, social and dietary changes leading to weaning stress syndrome. In order to compensate for the detrimental effects of weaning stress, antibiotics and natural extracts are used as feed additives, sometimes without fully understanding the interactions between them or even with low concentrations of mycotoxins that are frequently present in feed. The aim of this study was to evaluate the effect of fosfomycin (FOS), Cynara scolymus extract (CSE), deoxynivalenol (DON) and their combined administration on intestinal health of weaned piglets. The experiment was designed as a 2 × 2 × 2 factorial arrangement with 3 factors (FOS, CSE and DON treatments), 2 levels each (presence and absence) and 3 repeats. Weaned piglets (n = 24) were randomly divided in groups to receive the different treatments, namely DON administered in diet (50 μg/kg BW), FOS administered into the drinking water (30 mg/kg BW), CSE administered in diet (15 mg/kg BW) and all their combinations. After 15 d, the animals were euthanized and gastrointestinal tract samples were immediately taken to evaluate gastrointestinal pH, Enterobacteriaceae to lactic acid bacteria (E:L) ratio, volatile fatty acid (VFA) concentrations, disaccharidase (lactase, sucrase and maltase) activity, histology (intestinal absorptive area [IAA] and goblet cells count) and mucus ability to adhere pathogenic Escherichia coli. From our results, FOS and CSE treatments, individually or combined, produced a lower E:L ratio, an enhanced production of butyrate, increased disaccharidase activity (particularly maltase), and a greater IAA and goblet cells count along with an increase in pathogenic bacteria adherence to intestinal mucus. Deoxynivalenol did not show interactions with the other factors and its administration produced decreases on VFA, disaccharidase activity and goblet cells count. In conclusion, weaning piglets receiving diets containing FOS, CSE or both exhibited evident beneficial intestinal effects compared to animals receiving diets free from these compounds. On the contrary, the presence of DON at sub-toxic concentrations produced detrimental effects on intestinal health. The knowledge of the physiological and pathological gut changes produced by these compounds contributes to understand their potential productive consequences.

Effects of dietary supplementation of probiotic Enterococcus faecium on growth performance and gut microbiota in weaned piglets

The adverse effects of antibiotics have attracted widespread attention, thus reducing the use of antibiotics in animal feed has become a very important issue in improving of the health of livestock. The effects of Enterococcus faecium (E. faecium) on growth performance and gut microbiota in weaned piglets were investigated in the present study. Piglets were randomly assigned to four treatments: a control group fed with a diet containing 75 mg/kg aureomycin (Diet 1 group) and three experimental groups fed with diets of 50 mg/kg aureomycin (Diet 2 group), 50 mg/kg aureomycin + 9 × 10⁵ CFU/g E. faecium (Diet 3 group), or 50 mg/kg aureomycin + 1.2 × 10⁶ CFU/g E. faecium (Diet 4 group). Their gut microbial communities were analyzed by sequencing the V3–V4 region of the 16SrRNA gene. The results showed that the final body weights and the average daily gain of the weaned piglets in the Diet 2 group were higher (P = 0.05) than those in the Diet 1 or Diet 3 group. Decreasing trends (P = 0.08) was observed in mortality rate in the Diet 3 and 4 group when compared with that in the Diet 1 group. Increases in the Sobs, Chao1, ACE, and Shannon indexes and a decrease in the Simpson index were observed at intervals from day 1 to 14 (P < 0.05). The Sobs, Chao1, and ACE indexes in the Diet 3 group were the lowest on day 14 (P < 0.05). The abundance of Bacteroidetes was increased and that of Proteobacteria was decreased from day 1 to 7, but both of them kept stable from day 7 to 14. Besides, the lowest abundance of Fusobacteria, Lentisphaerae, and Planctomycetes was observed on day 1 and the lowest abundance of Actinobacteria was observed on day 14 in the Diet 3 group (P < 0.05). Overall, these results suggest that the antibiotics and E. faecium interventions result in different changes in the gut microbiota, and a reduced antibiotics diet supplemented with 1.2 × 10⁶ CFU/g E. faecium does not affect the growth performance in weaned piglets.

Prevalence of O-serogroups, virulence genes, and F18 antigenic variants in Escherichia coli isolated from weaned piglets with diarrhea in Korea during 2008-2016

To diagnose colibacillosis, detection of O-serogroups and virulence genes has been recommended worldwide. The prevalence of virulence factors can fluctuate over time. The objectives of this study were to determine the prevalence of O-serogroups, virulence genes, and F18 subtypes among pathogenic Escherichia coli isolated from weaned piglets with diarrhea in Korea. Between 2008 and 2016, 362 E. coli were isolated from weaned piglets with diarrhea. Hemolysis was determined in blood agar, and O-serogroups were identified using the slide agglutination technique. The genes for the toxins and fimbriae were amplified by polymerase chain reaction (PCR). Real-time PCR was conducted to discriminate between F18 subtypes. Although the most prevalent serogroup was O149 (11.3%) in the last 9 years, O139 (19.1%) became the most prevalent in recent years (2015–2016). The most predominant pathotype was enterotoxigenic E. coli (61.3%). The frequencies of Shiga-like toxin-producing E. coli (STEC) (23.4%), O139 (19.1%), Stx2e (35.1%), and F18ab (48.7%) increased over the most recent years. Although enterotoxigenic E. coli was the most predominant pathotype, the frequencies of O139, Stx2e, STEC, and F18ab have increased in recent years. These results demonstrate that there have been temporal changes in the predominant O-serogroups and virulence genes over the last decade in Korea. These findings can be practicable for use in epidemiology and control measures for enteric colibacillosis in Korean piggeries.

Deoxynivalenol Impairs Porcine Intestinal Host Defense Peptide Expression in Weaned Piglets and IPEC-J2 Cells

Host defense peptides (HDPs) are efficient defense components of the innate immune system, playing critical roles in intestinal homeostasis and protection against pathogens. This study aims to investigate the interference effects of DON on the intestinal porcine HDPs expression in piglets and intestinal porcine epithelial cell line (IPEC-J2) cells, and elucidate the underlying mechanisms through which it functions. In an animal experiment, intestinal HDPs were determined in weaned piglets fed control and 1.28 mg/kg or 2.89 mg/kg DON-contaminated diets. Dietary exposure to DON significantly decreased piglet average daily gain, increased intestinal permeability and depressed the expression of porcine β-defensin1 (pBD1), pBD2, pBD3, epididymis protein 2 splicing variant C (pEP2C), PMAP23, and proline/arginine-rich peptide of 39 amino acids (PR39) in the intestine (p < 0.05). In IPEC-J2 cells, DON decreased cell viability and inhibited the expression of pBD1, pBD3, pEP2C, PG1-5, and PR39 (p < 0.05). NOD2, key regulator that is responsible for HDPs production, was markedly downregulated, whereas caspase-12 was activated in the presence of DON. In conclusion, DON induced caspase-12 activation and inhibited the NOD2-mediated HDPs production, which led to an impaired intestinal barrier integrity of weaned piglets. Our study provides a promising target for future therapeutic strategies to prevent the adverse effects of DON.

Porcine deltacoronavirus induces TLR3, IL-12, IFN-α, IFN-β and PKR mRNA expression in infected Peyer's patches in vivo

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PDCoV infection caused severe diarrhea, virus shedding and intestinal lesion in weaned piglets.

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PDCoV could induce TLR3 mRNA expression in infected Peyer's patches from weaned piglets.

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PDCoV obviously induced IL-12, IFN-α, IFN-β, and PKR mRNA expression in infected Peyer's patches from weaned piglets.

Porcine deltacoronavirus (PDCoV) is a newly identified swine enteropathogenic coronavirus that causes watery diarrhea in piglets and results in significant economic losses to the pig industry. Currently there are no effective treatments or vaccines for PDCoV. In particular, the pathogenesis of PDCoV infection is still largely unknown. In this study, we reported that inoculating conventional weaned piglets with 1 × 10⁹ TCID₅₀ of the PDCoV CHN-GD-2016 strain by oral feeding could cause severe diarrhea. Virus RNA was detected in rectal swabs from 1 to 7 days post inoculation. In addition, microscopic lesions in small intestine were observed, and viral antigen also detected in the small intestines with PDCoV immunohistochemical staining. Importantly, PDCoV significantly induced mRNA expression of TLR3, IL-12, IFN-α, IFN-β, and PKR, the genes involved in modulation of the host immune responses, in infected Peyer's patches at 3 d.p.i., indicating that Peyer's patches play an important role in PDCoV immune responses in vivo. Collectively, our findings suggest that the observed gene expression profile might help explain immunological and pathological changes associated with PDCoV infection.

Influences of Copper/Zinc-Loaded Montmorillonite on Growth Performance, Mineral Retention, Intestinal Morphology, Mucosa Antioxidant Capacity, and Cytokine Contents in Weaned Piglets

The effects of copper/zinc-loaded montmorillonite (Cu/Zn-Mt) on growth performance, mineral retention, intestinal morphology, mucosa antioxidant capacity, and cytokine contents in weaned piglets were investigated in the present study. One hundred eight piglets weaned at 21 ± 1 days of age (Duroc × Landrace× Yorkshire; average initial weight of 6.36 kg) were allotted to three treatments for 2 weeks. The three treatments were as follows: (1) control group: basal diet; (2) Cu/Zn-Mt group: basal diet + 39 mg/kg Cu and 75 mg/kg Zn as Cu/Zn-Mt; (3) Cu + Zn + Mt group: basal diet + mixture of CuSO₄, ZnSO₄, and Mt (equal amount of Cu, Zn, and Mt to the Cu/Zn-Mt group). Each treatment had six pens of six piglets. The results showed that as compared with the control group and the Cu + Zn + Mt group, Cu/Zn-Mt supplementation increased (P < 0.05) the average daily gain and the gain/feed ratio; Cu/Zn-Mt supplementation increased (P < 0.05) the Cu and Zn concentrations in serum, jejunum, and ileum mucosa, villus height, the ratio of villus height to crypt depth, and the activities of SOD, GSH-Px, and IL-10 levels, and decreased the malondialdehyde concentrations in the jejunum and ileum, and intestinal IL-1β, IL-6, and TNF-α levels. Moreover, supplementation with the mixture of CuSO₄, ZnSO₄, and Mt had no effect on the growth performance, but increased the mucosa Cu and Zn concentrations, intestinal morphology, antioxidant capacity, and immune function in the duodenum, while it had no effect on the above indexes in the jejunum and ileum. The results indicated that Mt could be used as a controlled carrier for Cu and Zn, which made Cu/Zn-Mt have better biological activities in the intestine than the mixture of Cu, Zn, and Mt.

Effects of dietary Clostridium butyricum supplementation on growth performance, intestinal development, and immune response of weaned piglets challenged with lipopolysaccharide

Background

Weanling pigs, with immature immune system and physiological function, usually experience post-weaning diarrhea. This study determined the effects of dietary Clostridium butyricum supplementation on growth performance, diarrhea, and immunity of weaned pigs challenged with lipopolysaccharide (LPS).

Methods

In Experiment (Exp.) 1, 144 weaned piglets were weaned at 21 d and randomly assigned to six groups, with six replicates per group and four pigs per replicate, receiving a control diet (CON) or diet supplemented with antibiotics (AB) or C. butyricum (CB) (0.1%, 0.2%, 0.4%, or 0.8%), respectively. All diets in Exp. 1 were a highly digestible basal diet, with 3,000 mg/kg zinc oxide supplied in the first 2 wk only. In Exp. 2, 180 piglets were weaned at 21 d and randomly assigned to five groups, with six replicates per group and six pigs per replicate, receiving CON, AB, or CB (0.2%, 0.4%, or 0.6%) diets. The digestibility of diets was lower than those in Exp. 1, and did not include zinc oxide. At 36 d of Exp. 2, 12 piglets were selected from each of the CON and 0.4% CB groups, six piglets were intraperitoneally injected with LPS (50 μg/kg body weight) and the other six piglets with normal saline; animals were killed at 4 h after injection to collect blood, intestine, and digesta samples for biochemical analysis.

Results

In Exp. 1, CB and AB diets had no effect on growth performance of piglets. In Exp. 2, 0.4% CB decreased feed-gain ratio (P < 0.1), diarrhea score (P < 0.05), and increased duodenal, jejunal, and ileal villus height and jejunal villus height/crypt depth (P < 0.05). The 0.4% CB decreased the plasma tumor necrosis factor (TNF) α (P < 0.05) but increased ileal mucosa IL-10 and TLR2 mRNA expression (P < 0.05). Furthermore, 0.4% CB altered the microbial profile, with Bacillus and Ruminococcaceae UGG-003 at genus level and Lactobacillus casei and Parasutterella secunda at species level were higher than CON in colonic content (P < 0.05).

Conclusions

Dietary C. butyricum supplementation had positive effects on growth of weaned piglets with less digestible diets. There was a tendency to reduce the feed-gain ratio, which could reduce feed costs in pig production. Moreover, C. butyricum decreased post-weaning diarrhea by improving the intestinal morphology, intestinal microflora profile, and immune function.

Chitosan-Zn Chelate Downregulates TLR4-NF-κB Signal Pathway of Inflammatory Response and Cell Death-Associated Proteins Compared to Inorganic Zinc

The study was conducted to investigate the effect of chitosan-zinc chelate (CS-Zn) on TLR4-NF-κB signaling pathway and cell death-associated proteins in a weanling pig model. A total of 90 weaned piglets were allotted to three dietary treatments (the dietary treatments were as follows: (1) experimental diet with supplemental ZnSO₄ (150 mg Zn/kg diet), (2) experimental diet with supplemental CS-Zn (150 mg Zn/kg diet), and (3) experimental diet with a supplemental mixture of chitosan and ZnSO₄ (150 mg/kg Zn; the content of chitosan was equal to CS-Zn, which is according to molar basis)). The feeding trial lasted 30 days. The results showed that compared with ZnSO₄ or CS+ZnSO₄, CS-Zn decreased the expressions of the cell death-associated proteins Beclin-1, and Cleaved-Caspase3 and the ratio of LC3II/LC3I. The intestinal expressions of TLR4 and its downstream signals NF-κB, IKKβ, and IκBα were down-regulated simultaneously. Moreover, the contents of pro-inflammatory cytokines IL-2, TNF-α, and IFN-γ were decreased. The results indicated that as organic zinc source, CS-Zn was more effective than ZnSO₄ and the mixture of chitosan and ZnSO₄ for inhibiting inflammatory response and decreasing the expressions of proteins associated with cell death. The great anti-inflammatory effect of CS-Zn was modulated by inhibiting the TLR4-NF-κB signaling pathway, and the effect of CS-Zn on down-regulating the expression of cell death-associated proteins might also closely be associated with the TLR4-NF-κB signaling pathway.

Clinical impact of deoxynivalenol, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol on the severity of an experimental Mycoplasma hyopneumoniae infection in pigs

Background

The mycotoxin deoxynivalenol (DON) is highly prevalent in cereals in moderate climates and therefore pigs are often exposed to a DON-contaminated diet. Pigs are highly susceptible to DON and intake of DON-contaminated feed may lead to an altered immune response and may influence the pathogenesis of specific bacterial diseases. Therefore, the maximum guidance level in feed is lowest in this species and has been set at 900 μg/kg feed by the European Commission. This study aimed to determine the effect of in-feed administration of a moderately high DON concentration (1514 μg/kg) on the severity of an experimental Mycoplasma hyopneumoniae (M. hyopneumoniae) infection in weaned piglets. Fifty M. hyopneumoniae-free piglets were assigned at 30 days of age [study day (D)0] to four different groups: 1) negative control group (NCG; n = 5), 2) DON-contaminated group (DON; n = 15), 3) DON-contaminated and M. hyopneumoniae-inoculated group (DONMHYO; n = 15), 4) M. hyopneumoniae-inoculated group (MHYO; n = 15). The piglets were fed the experimental diets ad libitum for five weeks and were monitored during this period and euthanized at day 35 [27 days post infection (DPI)] or 36 (28 DPI). The main parameters under investigation were macroscopic lung lesions (MLL) at euthanasia, respiratory disease score (RDS) from day 8 until day 35, histopathologic lesions and log copies of M. hyopneumoniae DNA detected by qPCR, determined at the day of euthanasia.

Results

No significant difference was obtained for MLL at euthanasia, RDS (8–35), histopathologic lung lesions and log copies of M. hyopneumoniae DNA in the DONMHYO and MHYO group and consequently, no enhancement of the severity of the M. hyopneumoniae infection could be detected in the DONMHYO compared to the MHYO group.

Conclusions

Under present conditions, the findings imply that feed contaminated with DON (1514 μg/kg) provided to weaned pigs for five weeks did not increase the severity of an experimental M. hyopneumoniae infection. Further research is needed to investigate the impact of DON on M. hyopneumoniae infections in a multi-mycotoxin and multi-pathogen environment.

PID temperature controller in pig nursery: spatial characterization of thermal environment

The use of enhanced technologies of temperature control can improve the thermal conditions in environments of livestock facilities. The objective of this study was to evaluate the spatial distribution of the thermal environment variables in a pig nursery with a heating system with two temperature control technologies based on the geostatistical analysis. The following systems were evaluated: overhead electrical resistance with Proportional, Integral, and Derivative (PID) controller and overhead electrical resistance with a thermostat. We evaluated the climatic variables: dry bulb temperature (Tbs), air relative humidity (RH), temperature and humidity index (THI), and enthalpy in the winter, at 7:00, 12:00, and 18:00 h. The spatial distribution of these variables was mapped by kriging. The results showed that the resistance heating system with PID controllers improved the thermal comfort conditions in the pig nursery in the coldest hours, maintaining the spatial distribution of the air temperature more homogeneous in the pen. During the hottest weather, neither system provided comfort.

Arginine metabolism and its protective effects on intestinal health and functions in weaned piglets under oxidative stress induced by diquat

The intestine plays key roles in maintaining body arginine (Arg) homoeostasis. Meanwhile, the intestine is very susceptible to reactive oxygen species. In light of this, the study aimed to explore the effects of Arg supplementation on intestinal morphology, Arg transporters and metabolism, and the potential protective mechanism of Arg supplementation in piglets under oxidative stress. A total of thirty-six weaned piglets were randomly allocated to six groups with six replicates and fed a base diet (0·95 % Arg,) or base diet supplemented with 0·8 % and 1·6 % l-Arg for 1 week, respectively. Subsequently, a challenge test was conducted by intraperitoneal injection of diquat, an initiator of radical production, or sterile saline. The whole trial lasted 11 d. The diquat challenge significantly decreased plasma Arg concentration at 6 h after injection (P<0·05), lowered villus height in the jejunum and ileum (P<0·05) as well as villus width and crypt depth in the duodenum, jejunum and ileum (P<0·05). Oxidative stress significantly increased cationic amino acid transporter (CAT)-1, CAT-2 and CAT-3, mRNA levels (P<0·05), decreased arginase II (ARGII) and inducible nitric oxide synthase mRNA levels, and increased TNF- α mRNA level in the jejunum (P<0·05). Supplementation with Arg significantly decreased crypt depth (P<0·05), suppressed CAT-1 mRNA expression induced by diquat (P<0·05), increased ARGII and endothelial nitric oxide synthase mRNA levels (P<0·05), and effectively relieved the TNF- α mRNA expression induced by diquat in the jejunum (P<0·05). It is concluded that oxidative stress decreased Arg bioavailability and increased expression of inflammatory cytokines in the jejunum, and that Arg supplementation has beneficial effects in the jejunum through regulation of the metabolism of Arg and suppression of inflammatory cytokine expression in piglets.

Husbandry practices and gut health outcomes in weaned piglets: A review

The immediate post-weaning period is one of the most stressful phases in a pig's life, and during this period, piglets are usually exposed to environmental, social and psychological stressors which have direct or indirect effects on gut health and overall growth performance. In this review, the impact of husbandry practices on gut health outcomes and performance of piglets is discussed. Husbandry practices in the swine barn generally include nutrition and management practices, maintenance of hygienic standards and disease prevention protocols, and animal welfare considerations. Poor husbandry practices could result in reduced feed intake, stress and disease conditions, and consequently affect gut health and performance in weaned piglets. Reduced feed intake is a major risk factor for impaired gut structure and function and therefore a key goal is to maximize feed intake in newly weaned piglets. In weaned piglets, crowding stress could reduce pig performance, favor the proliferation of pathogenic bacteria resulting in diarrhea, stimulate immune responses and interfere with beneficial microbial activities in the gut. Sanitation conditions in the swine barn plays an important role for optimal piglet performance, because unclean conditions reduced growth performance, shifted nutrient requirements to support the immune system and negatively affected the gut morphology in weaned piglets. Appropriate biosecurity measures need to be designed to prevent disease entry and spread within a swine operation, which in turn helps to keep all pigs and piglets healthy. Collectively, husbandry practices relating to feeding and nutrition, animal welfare, biosecurity and disease prevention are important determinants of gut health and piglet performance. Thus, it is suggested that adopting high husbandry practices is a critical piece in strategies aimed at raising pigs without the use of in-feed antibiotics.

Dietary supplementation of encapsulated organic acids enhances performance and modulates immune regulation and morphology of jejunal mucosa in piglets

The aim of the study was to test two encapsulated regimens containing organic acids and/or zinc oxide (ZnO) on weaned piglet performance and jejunal mucosa morphology and immunity. For that, weaned piglets were allocated to treatments including control, supplemented with encapsulated organic acids (ACID group), and supplemented with organic acids and ZnO, both encapsulated (ACIDplus group). Antibiotics were used at similar concentrations in all groups during the first two weeks, but withdrawn from the ACIDplus group during the last three weeks of the experiment. ZnO was given with feed in the Control and ACID groups only during the first two weeks. The experimental period lasted 5 weeks. Piglets from the ACID group exhibited higher average daily gain compared to other groups during the last 3 weeks of the experiment (P<0.05). The ACIDplus group performed similarly with controls. The mucosal height of jejunum was higher in both ACID (P<0.01) and ACIDplus groups compared to controls (P<0.05). Immunohistochemical analysis of jejunal mucosa, showed higher numbers of neutrophils in ACID and ACIDplus groups compared to controls (P<0.01 and P<0.001, respectively). Treatments had the opposite effect on mucosal regulatory T-cells (Foxp3-positive cells) in jejunum, being higher (P<0.001) in control group compared to ACID and ACIDplus groups. The number of CD3-positive cells was higher (P<0.05) in the ACIDplus and control groups compared to the ACID group. In conclusion, the encapsulated products used had beneficial effects on growth performance coexisting with improvements on jejunal histomorphology and modulation of mucosal immunity.

Dietary Zinc Oxide Modulates Antioxidant Capacity, Small Intestine Development, and Jejunal Gene Expression in Weaned Piglets

The current study was conducted to investigate the effects of dietary zinc oxide (ZnO) on the antioxidant capacity, small intestine development, and jejunal gene expression in weaned piglets. Ninety-six 21-day-old piglets were randomly assigned to three dietary treatments. Each treatment had eight replicates with four piglets per replicate. The piglets were fed either control diet (control) or control diet supplemented with in-feed antibiotics (300 mg/kg chlortetracycline and 60 mg/kg colistin sulfate) or pharmacological doses of ZnO (3000 mg/kg). The experiment lasted 4 weeks. Blood samples were collected at days 14 and 28, while intestinal samples were harvested at day 28 of the experiment. Dietary high doses of ZnO supplementation significantly increased the body weight (BW) at day 14 and average daily gain (ADG) of days 1 to 14 in weaned piglets, when compared to control group (P < 0.05). The incidence of diarrhea of piglets fed ZnO-supplemented diets, at either days 1 to 14, days 14 to 28, or the overall experimental period, was significantly decreased in comparison with those in other groups (P < 0.05). Supplementation with ZnO increased the villus height of the duodenum and ileum in weaned piglets and decreased the crypt depth of the duodenum, when compared to the other groups (P < 0.05). Dietary ZnO supplementation decreased the malondialdehyde (MDA) concentration at either day 14 or day 28, but increased total superoxide dismutase (T-SOD) at day 14, when compared to that in the control (P < 0.05). ZnO supplementation upregulated the messenger RNA (mRNA) expression of zonula occludens-1 (ZO-1) and occludin in the jejunum mucosa of weaned piglets, compared to those in the control (P < 0.05). The pro-inflammatory cytokine interleukin-lβ (IL-1β) mRNA expression in the jejunum mucosa was downregulated in the ZnO-supplemented group, compared with the control (P < 0.05). Both in-feed antibiotics and ZnO supplementation decreased the mRNA expression of interferon-γ (IFN-γ), but increased the mRNA expression of transforming growth factor-β (TGF-β), in the jejunum mucosa of piglets, when compared to those in the control (P < 0.05). In summary, supplemental ZnO was effective on the prevention of post-weaning diarrhea (PWD) in weaned piglets and showed comparative growth-promoting effect on in-feed antibiotics, probably by the mechanism of improvement of the antioxidant capacity, restoration of intestinal barrier function and development, and modulation of immune functions.