Effects of wheat-based fermented liquid feed on growth performance, nutrient digestibility, gut microbiota, intestinal morphology, and barrier function in grower-finisher pigs.

Fermented liquid feed (FLF) can improve dietary nutrient absorption levels, degrade anti-nutrient factors in diets, and increase beneficial bacteria abundance in animal guts. However, few systematic studies have been conducted on WFLF in pigs. The present study evaluates the effects of WFLF on the growth performance, nutrient digestibility, gastric volume, intestinal morphology, intestinal health, intestinal barrier function, serum biochemical immunity, gut microbiota, and intestinal microbial diversity of grower-finisher pigs. In total, 80 weaned pigs were randomly allocated to two treatment groups based on their initial body weight: a basal diet with pellet dry feeding (CON) and a basal diet with wheat-based fermented liquid feed (WFLF), with four replicate pens per group. The experiment lasted 82 d. Compared with CON pigs, those fed WFLF were heavier significantly at 60-82 d and had significantly higher average daily feed intake, average daily gain, and gain: feed ratio at 60-82 d and 1-82 d. WFLF pigs had significantly greater jejunum, total tract, and ileal digestibility for all nutrients and amino acids, excluding arginine, than CON pigs. WFLF intake influenced villus height, villus height: crypt depth ratio of the anterior segment of the jejunum(A-jejunum), crypt depth, and redox potential of the posterior segment of the jejunum (P-jejunum) while significantly affecting body weight. Additionally, FLF improved gastric capacity significantly. Furthermore, mRNA expression of occludin and claudin-1 in the mucosa of the ileum and jejunum was significantly higher in WFLF pigs than in CON pigs. WFLF increased serum concentrations of alanine transaminase and reduced low-density lipoprotein cholesterol, total cholesterol, and total bile acid content. The alpha diversity (Shannon and Simpson indices) in the stomachs of WFLF pigs was significantly higher than in CON pigs. Microbial diversity in the stomach, ileum, and cecum, as well as the abundance of lactic acid bacteria, were increased in WFLF pigs compared to CON pigs. In conclusion, WFLF intake may positively influence intestinal ecology by improving digestive tract structure, upregulating intestinal barrier-related genes, and improving intestinal morphology to enhance intestinal digestive function and health. Collectively, the present study shows that WFLF intake can increase growth performance while maintaining beneficial nutrient digestibility in grower-finisher pigs.

Amniotes co-opt intrinsic genetic instability to protect germ-line genome integrity.

Unlike PIWI-interacting RNA (piRNA) in other species that mostly target transposable elements (TEs), >80% of piRNAs in adult mammalian testes lack obvious targets. However, mammalian piRNA sequences and piRNA-producing loci evolve more rapidly than the rest of the genome for unknown reasons. Here, through comparative studies of chickens, ducks, mice, and humans, as well as long-read nanopore sequencing on diverse chicken breeds, we find that piRNA loci across amniotes experience: (1) a high local mutation rate of structural variations (SVs, mutations ≥ 50 bp in size); (2) positive selection to suppress young and actively mobilizing TEs commencing at the pachytene stage of meiosis during germ cell development; and (3) negative selection to purge deleterious SV hotspots. Our results indicate that genetic instability at pachytene piRNA loci, while producing certain pathogenic SVs, also protects genome integrity against TE mobilization by driving the formation of rapid-evolving piRNA sequences.

The Outer Membrane Vesicles of Salmonella enterica Serovar Typhimurium Activate Chicken Immune Cells through Lipopolysaccharides and Membrane Proteins.

Salmonella is a common pathogen which can secrete outer membrane vesicles (OMVs). However, the effect of OMVs from Salmonella enterica Serovar Typhimurium (S. Typhimurium) of poultry origin on cells of the chicken innate immune system is not well known. In this study, S. Typhimurium OMVs were first isolated from three different poultry strains of Salmonella, Salmonella CVCC542, SALA, and SALB. In order to investigate the effect of OMVs on the maturation of monocytes into macrophages, both bone marrow-derived (BMD) monocytes and macrophage cell line HD11 cells were used. OMVs promoted the formation of monocyte dendrites in both types of cells, enabled BMD cells to become larger, and stimulated expression of LPS-induced TNF-αfactor (LITAF), IL-6, and inducible nitric oxide synthase (iNOS) genes in HD11 cells. These results demonstrated the capability of OMVs to promote the development of chicken monocytes into macrophages and the maturation of macrophages. In order to study the effect of OMVs on the phagocytosis of macrophages, chicken spleen-derived monocytes and HD11 cells were used. Phagocytosis of FITC-Salmonella and FITC-dextran by these two types of cells was enhanced after stimulation with OMVs. To determine which components in OMVs were responsible for the above observed results, OMVs were treated with proteinase K(PK) or polymyxin B (PMB). Both treatments reduced the phagocytosis of FITC-Salmonella by HD11 cells and chicken spleen mononuclear cells and reduced the secretion of IL-1ß, LITAF, and IL-6 cytokines. These results demonstrated that Salmonella OMVs activated chicken macrophages and spleen mononuclear cells and the activation was achieved mainly through lipopolysaccharides and membrane proteins.

Nitrate decreases methane production also by increasing methane oxidation through stimulating NC10 population in ruminal culture.

Studies proved that addition of nitrate in rumen could lead to reduction of methane emission. The mechanism of this function was involved in the competition effect of nitrate on hydrogen consumption and the inhibitory effect of generated nitrite on methanogen proliferation. The present study investigated an alternative mechanism that denitrifying anaerobic methane oxidizing (DAMO) bacteria, DAMO archaea and anammox bacteria may co-exist in rumen, therefore, more methane can be oxidized when addition of nitrate. Ruminal batch culture model was used to test the effects of addition of 5 mM NaNO3, 4 mM NH4Cl, or both into the culture substrate on methane production, fermentation patterns, and population of methanogens, NC10 and anaerobic methanotrophic-2d (ANME-2d). Our results showed that NC10 in the ruminal culture was detected by polymerase chain reaction (PCR) when using NC10 special primer sets, and addition of nitrate reduced methane production and the relative proportions of methanogen, whereas increased the relative proportion of NC10. A combined addition of ammonia salt and nitrate did not show further inhibitory effect on methane production but accelerated nitrate removal. We did not detect DAMO archaea in ruminal culture by real-time PCR when using ANME-2d special primer sets. The present study may encourage researchers to pay more attention to methane oxidation performed by anaerobic methanotroph when studying the strategies of inhibiting ruminal methane emission.