The small intestinal villus is covered with a thick layer of mucus that is secreted by goblet cells and functions primarily to first barrier from damage by toxic substance. Recent studies showed that goblet cells and mucins involved in complex immune function. Lipopolysaccharide (LPS) is widespread in the housing of livestock, which can induce bacterial infection symptoms and immunological stress within a short of time. Therefore, we aimed to study the effects of long-term exposure to different doses of LPS on intestinal mucus layer and immune barrier. The result showed that mucus layer thickness and goblet cell functions were significantly increased after low doses of LPS. The intestinal mucosal barrier can block the bacteria of the lumen, but LPS can penetrate this barrier into the blood, putting the body in a state of chronic low-grade inflammation and reducing the body’s immune function. However, after long-term exposure to high doses of LPS, a large number of lysosomes in goblet cells caused loss of function, and mucus layer thickness was significantly decreased. A large amount of LPS stuck to the mucus, leading to normal LPS and inflammatory cytokines level of plasma. The intestinal tissue morphology was damaged, and a number of immune cells were necrosis in the intestine. Collectively, long-term exposure to low doses of LPS lead to chronic low-grade inflammation in the body. Long-term exposure to high doses of LPS can be directly linked to the severity of the immunosuppression in the body.

Probiotics are suggested to improve pig health, nutrient utilisation, performance, and may reduce nitrogen (N) pollution. However, the effectivity of a single-strain might be different from 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. 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 8 boars/ treatment were weaned (day 0; 8.5 kg bodyweight). Until day 10, piglets were fed ad libitum and were housed in pairs; from day 11, piglets were fed semi ad libitum 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 jejunum and ileum, the apparent digestibility of CP was estimated and in ileum the apparent AA digestibility. In urine, 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 colon and faeces. Apparent CP digestibility in jejunum and ileum were not affected by treatment (P>0.05) and no effect was observed on apparent ileal digestibility of AA (P>0.05). Supplementation with the multi-strain probiotic improved ATTD of DM (P=0.01; +1.3%) and OM (P=0.02; +1.2%) and tended to improved 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 VFA, BCFA, and lactic acid content in the faeces (P>0.05). However, in colon, supplementation did influence lactic acid content (lower; P=0.01) and tended to influence valeric acid content (higher; P=0.09). In conclusion, results from the current study suggests that the multi-strain probiotic has the potential to contribute to improve nutrient efficiency in weaned piglets. More research needs to be done to identify the impact of the improved nutrient utilization on gut health in post-weaned pigs as well as environmental pollution.

Mutations in the Neuroligin-3 (Nlgn3) gene are implicated in autism spectrum disorder (ASD) and gastrointestinal (GI) dysfunction but cellular Nlgn3 expression in the enteric nervous system remains to be characterised. We combined RNAScope in situ hybridization for Nlgn3 mRNA and immunofluorescence for cholinergic and VIP-expressing submucosal neurons, nitrergic and calretinin-containing myenteric neurons and glial cells. We measured Nlgn3 mRNA neuronal and glial expression via quantitative 3-dimensional image analysis. To validate dual RNAScope/immunofluorescence data, we interrogated available single cell RNA sequencing (scRNASeq) data to assess for Nlgn3, Nlgn1, Nlgn2 and their binding partners, Nrxn1-3, MGDA1 and MGDA2, in enteric neural subsets. Most submucosal and myenteric neurons expressed Nlgn3 mRNA. In contrast to other Nlgns and binding partners, Nlgn3 was strongly expressed in enteric glia, suggesting a role for Neuroligin-3 in mediating enteric neuron-glia interactions. The autism-associated R451C mutation reduces Nlgn3 mRNA expression in cholinergic but not VIPergic submucosal neurons. In the myenteric plexus, Nlgn3 mRNA levels are reduced in calretinin and NOS labelled neurons and S100ß labelled glia. We provide a comprehensive cellular profile for neuroligin-3 expression in ileal neuronal subpopulations of mice expressing the R451C autism-associated mutation in Nlgn3, which may contribute to the understanding of the pathophysiology of GI dysfunction in ASD.