Bacillus subtilis-597 induces changes in lung pathology and inflammation during influenza A virus infection in pigs.

In recent years, it has become apparent that imbalances in the gastrointestinal system can impact organs beyond the intestine such as the lungs. Given the established ability of probiotics to modulate the immune system by interacting with gastrointestinal cells, our research aimed to investigate whether administering the probiotic strain Bacillus subtilis-597 could mitigate the outcome of influenza virus infection in pigs. Pigs were fed a diet either with or without the probiotic strain B. subtilis-597 for 14 days before being intranasally inoculated with a swine influenza A H1N2 strain (1 C.2 lineage). Throughout the study, we collected fecal samples, blood samples, and nasal swabs to examine viral shedding and immune gene expression. After seven days of infection, the pigs were euthanized, and lung and ileum tissues were collected for gene expression analysis and pathological examination. Our findings indicate that the administration of B. subtilis-597 exhibit potential in reducing lung lesions, possibly attributable to a general suppression of the immune system as indicated by reduced C-reactive protein (CRP) levels in serum, decreased expression of interferon-stimulated genes (ISGs), and localized reduction of the inflammatory marker serum amyloid A (SAA) in ileum tissue. Notably, the immune-modulatory effects of B. subtilis-597 appeared to be unrelated to the gastrointestinal microbiota, as the composition remained unaltered by both the influenza infection and the administration of B. subtilis-597.

Effect of Supplementing a Bacillus Multi-Strain Probiotic to a Post-Weaning Diet on Nutrient Utilisation and Nitrogen Retention of Piglets.

Probiotics are suggested to improve pig health, nutrient utilisation, performance, and they may reduce nitrogen (N) pollution. However, the effectivity of a single strain might be different from that of a multi-strain. The study was conducted to investigate the effect of a novel Bacillus multi-strain on nutrient digestibility, energy utilisation, and N retention in weaned piglets using an European diet. The experiment consisted of a control diet (CD) and a supplemented diet (SD). The probiotic used for SD consisted of B. amyloliquefaciens-516 and B. subtilis-541. A total of eight boars/treatment were weaned (day 0; 8.5 kg body weight). Only boars were used to ease the collection of urine. Until day 10, piglets were fed ad libitum and were housed in pairs; from day 11, piglets were fed semi ad libitum (feeding level 3.2× metabolic body weight) and were housed individually. From day 14, faecal and urine were collected twice daily. Piglets were humanely euthanised at day 19 (15.0 kg bodyweight) after which the jejunum, ileum, and colon content were collected. In faeces, the apparent total tract digestibility (ATTD) of, amongst others, DM, organic matter (OM), crude protein (CP), non-starch polysaccharides (NSP), and subsequently net energy (NE) were calculated using titanium dioxide as an indigestible marker. In the jejunum and ileum, the apparent digestibility of CP was estimated, and in the ileum, the apparent AA digestibility was measured. In urine, the N content was measured to determine N retention. The volatile fatty acid (VFA), branched-chain fatty acid (BCFA), and lactic acid content were analysed in the colon and faeces. The apparent CP digestibility in the jejunum and ileum was not affected by treatment (p > 0.05), and no effect was observed on the apparent ileal digestibility of AA (p > 0.05). Supplementation with the multi-strain probiotic improved the ATTD of DM (p = 0.01; +1.3%) and OM (p = 0.02; +1.2%) and tended to improve the ATTD of CP (p = 0.10; +2.2%) and NSP (p = 0.07; +1.9%). The multi-strain probiotic also improved the NE value (p = 0.02; +0.2 MJ/kg DM) and improved N retention (p = 0.05; +1.6%). Supplementation did not influence the VFA, BCFA, and lactic acid content in the faeces (p > 0.05). However, in the colon, supplementation did influence the lactic acid content (lower; p = 0.01) and tended to influence the valeric acid content (higher; p = 0.09). In conclusion, results from the current study suggest that the multi-strain probiotic has the potential to contribute to improve nutrient efficiency in weaned piglets. More research needs to be conducted to identify the impact of the improved nutrient utilisation on gut health in post-weaned pigs as well as environmental pollution.

The Effect of a Bacillus-Based Probiotic on Sow and Piglet Performance in Two Production Cycles.

The aim of this study was to assess the impact of Bacillus-based probiotic diets on reproduction performance, fecal scores, microflora, and economic factors in lactating sows and suckling piglets across two productive cycles. A total of 96 sows, reared in a continuous farrowing system for two full cycles, were divided into two groups: a control group and an experimental group. Sows were fed a basal diet without the probiotic or a diet supplemented with viable bacterial spores. At seven days of age, control group piglets were offered standard creep feed, whereas piglets in the experimental (probiotic) group received a diet containing the probiotic fed to their dams. Sows receiving probiotic-supplemented diets were characterized by significantly higher (p ≤ 0.05) average daily feed intake in lactation, lower (p ≤ 0.01) body weight (BW) loss during lactation, and reduced loss of backfat thickness as well as higher body condition score after lactation. Dietary probiotic supplementation increased (p ≤ 0.01) birth weight, total creep feed consumption, litter weight gain, and piglet weaning weight. The probiotic also improved (p ≤ 0.01) overall fecal scores, decreased total E. coli count on day seven and Clostridium perfringens count (trend) in sucking piglets. The total feed cost per weaned piglet was lower in the experimental (probiotic) group. Supplementing the diet with a probiotic containing Bacillus strains improved the reproductive performance of sows and the performance and health of piglets.