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Reduction of post-weaning diarrhoea caused by ETEC is a principal objective in pig farming in terms of welfare benefits. This study determined the effects of genetic susceptibility and dietary strategies targeting inflammation and fimbriae adherence on F4-ETEC shedding and diarrhoea in weaned piglets in an experimental challenge model. A DNA marker test targeting single nucleotide polymorphism 2 (SNP2) identified piglets as heterozygous (SNP2+, susceptible) or homozygous (SNP2-, resistant) to developing F4ac-ETEC diarrhoea. A total of 50 piglets, 25 SNP2+ and 25 SNP2-, were weaned at 30 days of age and equally distributed to different treatments (n = 10): Positive control (PC): piglets fed with a negative control diet and provided with colistin via drinking water; Negative control (NC): piglets fed with a negative control diet; Tall oil fatty acids (TOFA): piglets fed with a negative control diet + 1.0 g TOFA/kg feed; Yeast hydrolysate (YH): piglets fed with a negative control diet + 1.5 g YH/kg feed derived from Saccharomyces cerevisiae; and Combination (COM): piglets fed with a negative control diet + 1.0 g TOFA and 1.5 g YH/kg feed. On day 10 post-weaning, all piglets were infected with F4-ETEC by oral administration. Piglets fed with PC, TOFA, YH or COM had a lower faecal shedding of F4-ETEC than NC piglets (P < 0.001), which was also shorter in duration for PC and TOFA piglets than for NC piglets (P < 0.001). Piglets in PC, TOFA, YH and COM had a shorter diarrhoea duration versus NC when classified as SNP2+ (P = 0.02). Furthermore, PC, TOFA and YH piglets grew more than NC and COM piglets in the initial post-inoculation period (P < 0.001). In addition, the level of faecal F4-ETEC shedding and the percentage of pigs that developed F4-ETEC diarrhoea (72 vs. 32%, P < 0.01) following infection were higher, and the duration of F4-ETEC diarrhoea longer (2.6 vs. 0.6 days, P < 0.001), in SNP2+ piglets than in SNP2- piglets, and led to reduced growth performance (P = 0.03). In conclusion, piglets fed with TOFA, YH or their combination, irrespective of their SNP2 status, are more resilient to F4-ETEC infection. Moreover, SNP2+ piglets show a higher level of F4-ETEC shedding and diarrhoea prevalence than SNP2- piglets, confirming an association between SNP2 and F4ac-ETEC susceptibility., (© 2024. The Author(s).)

Enterotoxigenic E. coli (ETEC) susceptibility in pigs is highly influenced by their genotype. The aim of this study was to determine the association between CHCF1 genotype and ETEC F4ab susceptibility in experimentally infected pigs. We investigated ETEC diarrhea development in CHCF1 heterozygous susceptible (RS) (n = 12 pigs) compared to CHCF1 homozygous resistant (RR) (n = 12 pigs) for six days after ETEC F4ab challenge. Afterwards, we genotyped with MUC4 and MUC13 markers to relate performance in identifying ETEC F4ab diarrhea susceptible pigs. In the CHCF1 RS group, 12/12 pigs developed ETEC diarrhea compared with 0/12 pigs in the CHCF1 RR group. Weight gain was lower in CHCF1 RS pigs compared with RR pigs (mean ± SD: 208 ± 323 g and 987 ± 615 g, p = 0.0007). Further, the shedding of hemolytic E. coli was significantly higher in CHCF1 RS pigs from 2 to 6 days post inoculation and they shed the challenge strain for more days (mean ± SD: 3.5 ± 1.6 days versus 0.5 ± 0.5 days, p < 0.0001). Twelve pigs with ETEC diarrhea were misclassified as resistant with the MUC4 marker and four pigs without ETEC diarrhea were misclassified as susceptible with the MUC13 marker. We found complete association between CHCF1 genotype and ETEC diarrhea development in pigs from a herd with Danbred genetics. The CHCF1 marker was more likely to determine the true host susceptibility to ETEC F4ab than the other markers. The marker shows potential for improving reliability of PWD challenge models and potentially for use in breeding for ETEC F4ab/ac resistance., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: The association between the porcine pre-weaning gut microbiota composition and diversity, and subsequent post-weaning diarrhea (PWD) susceptibility is currently being studied. In this longitudinal study, we examined the association between pre-weaning fecal microbiome composition and diversity, and PWD development in a Danish sow herd., Methods: Forty-five pigs were followed from birth until 7 days after weaning (post-natal day (PND) 33). At PND 33, the pigs were categorized as PWD cases or healthy controls based on fecal consistency. We compared their fecal microbiomes at PND 8, late lactation (PND 27) and 7 days post weaning (PND 33) using 16S rRNA V3 region high-throughput sequencing. At PND 27 and 33, we also weighed the pigs, assessed fecal shedding of hemolytic Escherichia coli by culture and characterized hemolytic isolates by ETEC virulence factors with PCR and by whole genome sequencing., Results: A total of 25 out of 45 pigs developed PWD and one Enterotoxigenic E. coli strain with F18:LT:EAST1 virotype was isolated from most pigs. At PND 33, we found differences in beta diversity between PWD and healthy pigs ( R 2 = 0.027, p = 0.009) and that body weight was associated with both alpha and beta diversity. Pre-weaning fecal microbiome diversity did not differ between PWD and healthy pigs and we found no significant, differentially abundant bacteria between them., Conclusion: In the production herd under study, pre-weaning fecal microbiome diversity and composition were not useful indicators of PWD susceptibility., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Rydal, Gambino, Castro-Mejia, Poulsen, Jørgensen and Nielsen.)

Host genotype is important for enterotoxigenic E. coli (ETEC) susceptibility. We conducted two trials to evaluate the effect of CHCF1 genotype on incidence of ETEC diarrhea. In trial 1 (n = 15 pigs), pigs were inoculated with 10 8  CFU or 10 10  CFU doses of an ETEC F4ac strain. In trial 2 (n = 33 pigs), pigs were inoculated with ETEC F4ab or F4ac. Across trials, all inoculated pigs that developed ETEC diarrhea were CHCF1 heterozygous susceptible (6/6). No inoculated CHCF1 homozygous resistant pigs developed ETEC diarrhea (0/26). Susceptibility towards ETEC F4ac/ab infection might correspond with CHCF1 genotype., (© 2022. The Author(s).)

Anemia is a common condition in sow herds. We aimed to study the effects of severe iron deficiency during gestation on sow and piglet health outcomes with an experimental model for blood-removal-induced iron deficiency anemia. In total, 18 multiparous sows (8 in trial I and 10 in trial II) were allocated to either a blood removal group or a control group. Hematologic parameters were monitored at regular intervals and the tissue iron concentrations were measured for the sows and newborn piglets after farrowing. In trial I, the mean liver iron content was reduced to 46.7 µg/g in the blood removal sows compared to 252.6 µg/g in the controls ( p < 0.001). In trial II, sows in the blood removal group had lower iron content in the liver (147.8 µg/g), kidney (46.3 µg/g) and spleen (326.5 µg/g) compared to the control sows (323.2 µg/g, 81.3 µg/g and 728.9 µg/g, respectively; p = 0.009, 0.016, 0.01, respectively). In trial I, piglets from sows in the blood removal group had significantly decreased hematocrit (Hct), red blood cells (RBC) and a tendency for reduced hemoglobin (Hb) compared to the control piglets. We established a blood removal model that resulted in mild- to severe degrees of sow anemia and reduced tissue iron stores at farrowing.

Optimal nutrition is important after preterm birth to facilitate normal brain development. Human milk is rich in sialic acid and preterm infants may benefit from supplementing formula with sialyllactose to support neurodevelopment. Using pigs as models, we hypothesized that sialyllactose supplementation improves brain development after preterm birth. Pigs (of either sex) were delivered by cesarean section at 90% gestation and fed a milk diet supplemented with either an oligosaccharide-enriched whey with sialyllactose ( n = 20) or lactose ( n = 20) for 19 days. Cognitive performance was tested in a spatial T-maze. Brains were collected for ex vivo magnetic resonance imaging (MRI), gene expression, and sialic acid measurements. For reference, term piglets ( n = 14) were artificially reared under identical conditions and compared with vaginally born piglets naturally reared by the sow ( n = 12). A higher proportion of sialyllactose supplemented preterm pigs reached the T-maze learning criteria relative to control preterm pigs ( p < 0.05), and approximated the cognition level of term reference pigs ( p < 0.01). Furthermore, supplemented pigs had upregulated genes related to sialic acid metabolism, myelination, and ganglioside biosynthesis in hippocampus. Sialyllactose supplementation did not lead to higher levels of sialic acid in the hippocampus or change MRI endpoints. Contrary, these parameters were strongly influenced by postconceptional age and postnatal rearing conditions. In conclusion, oligosaccharide-enriched whey with sialyllactose improved spatial cognition, with effects on hippocampal genes related to sialic acid metabolism, myelination, and ganglioside biosynthesis in preterm pigs. Dietary sialic acid enrichment may improve brain development in infants.