Effects of E. coli bivalent vaccine and of host genetic susceptibility to E. coli on the growth performance and faecal microbial profile of weaned pigs

Effects of stimbiotic supplementation on gut health, immune response, and intestinal microbiota in weaned piglets challenged with E. coli

In order to make piglet diets more effective, it is necessary to investigate effective methods for breaking down xylan in cereal. The objective of this study was to determine the effects of dietary stimbiotic (STB) supplementation on growth performance, intestinal morphology, immune response and intestinal microbiota in weaned piglets. A total of 24 (Duroc × Yorkshire × Landrace) weaned pigs (initial body weight of 8.01 ± 0.38 kg and 28 ± 3 d old), were assigned to 4 treatments with 6 replicates per treatment. Pigs were housed in individual pens for 17 days, including 5 days adaption period and 12 days after the first Escherichia coli (E. coli) challenge. The experiment was conducted in a 2 × 2 factorial arrangement of treatments consisting of two levels of challenge (challenge and non-challenge) and two levels of STB (0 and 0.5 g/kg diet). Supplementations of STB 0.5 g/kg improved the gain to feed ratio (G:F) (P < 0.05) in piglets challenged with shiga toxigenic E. coli (STEC). STB supplementation decreased (P < 0.05) white blood cells, neutrophils, lymphocytes, and expression levels of tumor necrosis factor-alpha and interleukin-6. Supplementation of STB improved (P < 0.05) the lymphocytes and neutrophils in piglets challenged with STEC on 12 dpi. Supplementation of STB also improved (P < 0.05) the villus height to-crypt depth ratio of ileum in piglets challenged with STEC. Supplementation of STB increased (P < 0.05) the expression levels of claudin-1 of ileum. In genus level, supplementation of STB increased (P < 0.001) the abundance of Prevotella compared to non-supplementation of STB groups in pre-inoculation period. Also, supplementation of STB decreased (P < 0.05) the abundance of Faecalibacterium and Eubacterium_coprostanoligenes_group compared to non-supplementation of STB groups in post-inoculation period. In phylum level, supplementation of STB increased (P < 0.05) the abundance of Desulfobacterota and Fibrobacterota in pre-inoculation period. E. coli challenge increased the abundance of Fibrobacterota compared to non-challenged group in post-inoculation period. In conclusion, these findings indicated that STB supplementation could alleviate a decrease of the performance, immune response, and inflammatory response in piglets induced by the STEC challenge.

Is Oral Vaccination against Escherichia coli Influenced by Zinc Oxide?

BACKGROUND

Although zinc oxide has been banned at therapeutic doses in the EU, its use is still legal in most countries with industrial pig farming. This compound has been shown to be very effective in preventing E. coli-related diseases. However, another strategy used to control this pathogen is vaccination, administered parenterally or orally. Oral vaccines contain live strains, with F4 and F18 binding factors. Since zinc oxide prevents E. coli adhesion, it is hypothesised that its presence at therapeutic doses (2500 ppm) may alter the immune response and the protection of intestinal integrity derived from the vaccination of animals.

METHODS

A group of piglets were orally vaccinated at weaning and divided into two subgroups; one group was fed a feed containing 2500 ppm zinc oxide (V + ZnO) for the first 15 days post-vaccination (dpv) and the other was not (V). Faeces were sampled from the animals at 6, 8, 11, 13, and 15 dpv. Unvaccinated animals without ZnO in their feed (Neg) were sampled simultaneously and, on day 15 post-vaccination, were also compared with a group of unvaccinated animals with ZnO in their feed (ZnO).

RESULTS

Differences were found in E. coli excretion, with less quantification in the V + ZnO group, and a significant increase in secretory IgA in the V group at 8 dpv, which later equalised with that of the V + ZnO group. There was also some difference in IFNα, IFNγ, IL1α, ILβ, and TNFα gene expression when comparing both vaccinated groups (p < 0.05). However, there was no difference in gene expression for the tight junction (TJ) proteins responsible for intestinal integrity.

CONCLUSIONS

Although some differences in the excretion of the vaccine strain were found when comparing both vaccinated groups, there are no remarkable differences in immune stimulation or soluble IgA production when comparing animals orally vaccinated against E. coli in combination with the presence or absence of ZnO in their feed. We can conclude that the immune response produced is very similar in both groups.

Productive and physiological implications of top-dress addition of branched-chain amino acids and arginine on lactating sows and offspring

BACKGROUND

Branched-chain amino acids (BCAAs), including L-leucine (L-Leu), L-isoleucine (L-Ile), L-valine (L-Val), and L-arginine (L-Arg), play a crucial role in mammary gland development, secretion of milk and regulation of the catabolic state and immune response of lactating sows. Furthermore, it has recently been suggested that free amino acids (AAs) can also act as microbial modulators. This study aimed at evaluating whether the supplementation of lactating sows with BCAAs (9, 4.5 and 9 g/d/sow of L-Val, L-Ile and L-Leu, respectively) and/or L-Arg (22.5 g/d/sow), above the estimated nutritional requirement, could influence the physiological and immunological parameters, microbial profile, colostrum and milk composition and performance of sows and their offspring.

RESULTS

At d 41, piglets born from the sows supplemented with the AAs were heavier (P = 0.03). The BCAAs increased glucose and prolactin (P < 0.05) in the sows' serum at d 27, tended to increase immunoglobulin A (IgA) and IgM in the colostrum (P = 0.06), increased the IgA (P = 0.004) in the milk at d 20 and tended to increase lymphocyte% in the sows' blood at d 27 (P = 0.07). Furthermore, the BCAAs tended to reduce the Chao1 and Shannon microbial indices (P < 0.10) in the sows' faeces. The BCAA group was discriminated by Prevotellaceae_UCG-004, Erysipelatoclostridiaceae UCG-004, the Rikenellaceae_RC9_gut_group and Treponema berlinense. Arginine reduced piglet mortality pre- (d 7, d 14) and post-weaning (d 41) (P < 0.05). Furthermore, Arg increased the IgM in the sow serum at d 10 (P = 0.05), glucose and prolactin (P < 0.05) in the sow serum at d 27 and the monocyte percentage in the piglet blood at d 27 (P = 0.025) and their jejunal expression of NFKB2 (P = 0.035) while it reduced the expression of GPX-2 (P = 0.024). The faecal microbiota of the sows in Arg group was discriminated by Bacteroidales. The combination of BCAAs and Arg tended to increase spermine at d 27 (P = 0.099), tended to increase the Igs (IgA and IgG, P < 0.10) at d 20 in the milk, favoured the faecal colonisation of Oscillospiraceae UCG-005 and improved piglet growth.

CONCLUSION

Feeding Arg and BCAAs above the estimated requirements for milk production may be a strategy to improve sow productive performance in terms of piglet average daily gain (ADG), immune competence and survivability via modulation of the metabolism, colostrum and milk compositions and intestinal microbiota of the sows. The synergistic effect between these AAs, noticeable by the increase of Igs and spermine in the milk and in the improvement of the performance of the piglets, deserves additional investigation.

Translational Approach to Induce and Evaluate Verocytotoxic E. coli O138 Based Disease in Piglets

Simple Summary

The aim of the study was to set up experimental conditions to simulate the simultaneous outbreak of post-weaning diarrhea and enterotoxaemia in weaned piglets, through verocytotoxic O138 Escherichia coli challenge. Zootechnical, clinical, microbiological, histological and immunological parameters were evaluated along the follow-up of control and infected groups. Results showed that experimental infection significantly affected the clinical status. Infected animals showed significant higher total median scores of epiphora, vitality, hair irregularity, oedema and depression; in addition, they displayed evident inflammatory infiltrate of lymphocytes, and follicular hyperplasia, increase of IgG in the intestinal crypts and CD3-positive T cells in intestinal epithelium. The infection model, carried out on receptor-mediated susceptible piglets, allowed to identify a discriminative panel of clinical symptoms related to Escherichia coli O138 infection and could be used to assess the protective effect of antibiotic alternatives.

Abstract

Pig livestock was influenced by several global concerns that imposed a re-thinking of the farming system, which included the reduction in chemical dependency and the development of antimicrobial alternatives. Post-weaning diarrhea and enterotoxaemia caused by Escherichia coli, are serious threats that are responsible for the economic losses related to mortality, morbidity and stunted growth in weaning piglets. The aim of the study was to set up experimental conditions to simulate the simultaneous outbreak of post-weaning diarrhea and enterotoxaemia in weaned piglets, through verocytotoxic O138 Escherichia coli challenge, with a multidisciplinary approach. Eighteen piglets susceptible to F18 VTEC infection were selected by polymerase chain reaction for polymorphism on the fucosyltransferase 1 gene and randomly divided in two experimental groups, non-infected controls (C; n = 6) and infected ones (I; n = 12) and housed into individual pens at the same environmental conditions for 29 days. At day 20, I pigs were orally inoculated with Escherichia coli O138 and fed a high protein ration for 3 days. Zootechnical, clinical, microbiological, histological and immunological parameters were evaluated along the follow up (3 and 9 days). Experimental infection, confirmed by bacteria faecal shedding of the I group, significantly affected the clinical status. The I group showed significantly higher total scores, corresponding to medians of the sum of daily scores from days 1 to 3 (Σ3) and 1 to 9 (Σ9) post infection, epiphora, vitality, hair irregularity, oedema and depression. Histological examination showed evident inflammatory infiltrate of lymphocytes, and follicular hyperplasia in I pigs; in the same group, the immunohistochemical and immunological assays revealed an increase in IgG in the intestinal crypts and CD3-positive T cells in intestinal epithelium. The experimental Escherichia coli infection in controlled conditions is crucial for both the evaluation of innovative compounds and the elucidation of the mechanisms associated with the persistence of antibacterial resistant strains. In conclusion, the adopted infection model, carried out on receptor-mediated susceptible piglets, allowed us to identify a discriminative panel of clinical symptoms related to Escherichia coli O138 infection, and could be used to assess the protective effect of antibiotic alternatives.

Timely Control of Gastrointestinal Eubiosis: A Strategic Pillar of Pig Health

The pig gastrointestinal tract (GIT) is an open ecosystem in which microorganisms and their host are mutually involved and continually adapt to different factors and problems which may or may not be host dependent or due to the production system. The aim of the present review is to highlight the factors affecting the GIT microbial balance in young pigs, focusing on the pre- and post-weaning phases, to define a road map for improving pig health and the production efficiency of the food chain. Birth and weaning body weight, physiological maturation, colostrum and milk (composition and intake), genetic background, environmental stressors and management practices, antibiotic use and diet composition are considered. Overall, there is a lack of knowledge regarding the effect that some factors, including weaning age, the use of creep feed, the composition of the colostrum and milk and the use of antibiotics, may have on the gut microbiome of piglets. Furthermore, the information on the gut microbiome of piglets is mainly based on the taxonomy description, while there is a lack of knowledge regarding the functional modification of the microbiota, essential for the exploitation of microbiota potential for modulating pig physiology.