Heat stress can lead to decreased feed intake, apoptosis of mammary epithelial cells, and decreased milk yield and quality. Selenium is an important element in the composition of at least 25 selenoproteins. Hydroxy-selenomethionine (HMSeBA) is a novel organic selenium that has been shown to have a better deposition effect. However, whether HMSeBA alleviates damage to the mammary gland blood-milk barrier caused by heat stress and how this affects the performance of dairy cows remain largely unexplored. Therefore, 32 healthy Holstein cows with similar gestation days (150.41 ± 20.07 d), milk yield (36.15 ± 3.02 kg) and parity (3.25 ± 0.51) were selected and randomly divided into two total mixed rations with different selenium (Se) sources: sodium selenite (SSe) and HMSeBA. This study evaluated the outcomes of HMSeBA on antioxidant capacity, immunity, and blood-milk barrier damage in dairy cows during heat stress by collecting the samples of blood, rumen fluid and mammary gland biopsy. The experiment was conducted over 35 d, including a 5-day pre-feeding period and a 30-day experimental period. The temperature and humidity index (THI) were all above 80 throughout the experiment period. The results showed that HMSeBA decreased the respiratory rate (P < 0.001) and the content of inflammatory cytokines in the serum and increased the content of immune factors and antioxidant capacity (P < 0.05). In addition, HMSeBA reduced the expression of inflammatory cytokines and heat shock proteins in mammary gland (P < 0.05). Hematoxylin-eosin-stained pathological sections showed massive thickening of acinar walls and severe destruction of glandular structures in the SSe group, but the structure of the acinar mammary gland in the HMSeBA group was intact. Furthermore, HMSeBA promoted the expression of the phosphatidylinositol 3-kinase (PI3K, P < 0.001)/protein kinase B (AKT, P = 0.011)/mammalian target of rapamycin (mTOR, P = 0.008) pathway and improved the expression of zonula occludens-1 (ZO-1, P = 0.014) and occluding (OCLN, P = 0.012) in the mammary gland, suggesting less damage caused by heat stress to the blood-milk barrier. Our results demonstrated that HMSeBA can improve the antioxidant capacity and immunity of dairy cows and the expression of tight junction proteins in mammary gland to help alleviate the blood-milk barrier damage by heat stress, which could reduce the damage of heat stress on milk yield.

The use of next-generation probiotics (NGP) in pigs for combating diseases has been subject to limited research. Here we explored the potential of a well-known NGP candidate Akkermansia muciniphila targeting pig gut health. In the first screening experiment, we found that the abundance of A. muciniphila peaked at 14 d old but decreased at weaning (21 d old; P < 0.05), suggesting the weaning period may be an effective window for A. muciniphila intervention. Following that, 48 crossbred weaned pigs at 28 d old were randomly assigned to five groups: control (CON), high/low live A. muciniphila (HA/LA), and high/low heat-killed A. muciniphila (HIA/LIA). From 1 to 28 d old, the CON group received gastric infusion of anaerobic sterile saline every other day; the HA and LA groups were gavaged every other day with 1 × 10¹⁰ CFU/5 mL and 5 × 10⁸ CFU/5 mL live A. muciniphila, respectively; and the HIA and LIA groups were gavaged every other day with 1 × 10¹⁰ CFU/5 mL and 5 × 10⁸ CFU/5 mL heat-killed A. muciniphila, respectively. At d 29, pigs in the CON group were randomly and equally divided into two groups, one of which was named the enterotoxigenic Escherichia coli (ETEC) group, and all groups except CON received a 5-d ETEC challenge. The supplementation of A. muciniphila numerically reduced the diarrhea rate of weaned pigs compared to the pigs that only received the ETEC challenge (P = 0.57), but the LIA group had a higher diarrhea rate than the CON group (P < 0.05). Consistent with this, the supplementation of A. muciniphila improved the small intestinal morphology and structure, proportion of CD4⁺ T lymphocytes in the blood, as well as the expression of genes related to intestinal barrier and antioxidant indices of pigs with ETEC challenge, especially for the LA group (P < 0.05). Meanwhile, A. muciniphila supplementation reduced the expression of ETEC virulence factor genes in the ileum and colon of pigs challenged by ETEC (P < 0.05). Therefore, A. muciniphila may protect the intestinal health of weaned piglets from damage caused by ETEC infection, but the effect may vary depending on the concentration and activity of A. muciniphila.

Feedstuffs derived from canola, predominantly canola meals plus whole, "full-fat" canola seed, and even canola protein isolates and/or concentrates, have the potential to decrease soybean meal inclusions in diets for broiler chickens. The protein content of soybean meal exceeds that of canola meal; however, canola meal contains more methionine and cysteine in absolute and relative terms. The purpose of this review is to explore this potential as Australian chicken-meat production is uniquely positioned to take advantage of this opportunity to the extent that it can be realised. Australia harvests ample quantities of canola, the bulk of which is exported as seed; alternatively, soybean production is very limited; therefore, large quantities of soybean meal are imported as the principal source of dietary protein for broiler chickens. This importation of soybean meal is not sustainable; however, canola meal inclusions in broiler diets do not usually exceed 100 g/kg. Regression equations derived from 15 recent studies indicate that dietary inclusions of 150 g/kg solvent-extracted canola meal would compromise weight gain by 4.04% and feed conversion ratio (FCR) by 4.72%. The foremost factors driving these depressions in canola meal are probably (1) high fibre contents coupled with low energy densities and (2) the presence of glucosinolates, which may be converted into toxic metabolites including thiocyanates. Moreover, regression equations from nine studies suggest that calculated dietary glucosinolate concentrations of 2.00 μmol/g would compromise weight gain by 5.72% and FCR by 6.56%. The nutritive value of canola meal could be enhanced by improvements in canola breeding programs, processing methods in canola meal production, and dietary formulations including judicious application of exogenous enzymes. Consideration is given to these aspects in this review as any improvements would increase the extent to which canola meal can feasibly replace soybean meal in broiler diets. An additional pathway to decrease the reliance on soybean meal could be the adoption of reduced-crude protein (CP) diets containing canola meal. The combined strategy of canola meal replacing soybean meal in reduced-CP diets, if successful, would tangibly decrease soybean meal requirements in global chicken-meat production.

This study sought to determine the effects of rosemary leaf powder (RP) on laying performance, egg quality, serum indices, gut barrier function, and cecal microbiota and metabolites of late-phase laying hens. A total of 84 "Jing Tint 6" laying hens at 65-week old were randomly divided into 2 groups and fed either a basal diet (CON) or a basal diet supplemented with 0.3% RP. Our study revealed that RP improved the Haugh unit and decreased yolk n-6/n-3 polyunsaturated fatty acid (PUFA) ratio of laying hens, increased serum superoxide dismutase (SOD), jejunal activities of SOD and catalase (CAT), and jejunal zonula occludens-1 (ZO-1) expression, as well as decreased serum tumor necrosis factor-α (TNF-α) level and jejunal TNF-α mRNA expression. Rosemary leaf powder markedly enhanced (P < 0.05) cecal abundances of Rikenellaceae, Rikenellaceae_RC9_gut_group, and Turicibacter, tended to promote (P = 0.076) butyrate concentration, and reduced (P < 0.05) cecal abundances of Erysipelatoclostridiaceae, Sutterellaceae, Fusobacteriaceae, Campylobacteraceae, Sutterella, Campylobacter, and Fusobacterium, which were closely linked with Haugh unit, yolk n-6/n-3 PUFA ratio, serum SOD and TNF-α. In addition, RP altered the metabolic functions of cecal microbiota and enhanced the abundances of butyrate-synthesizing enzymes, including lysine 2,3-aminomutase, β-lysine 5,6-aminomutase, and 3-oxoacid CoA-transferase. Together, 0.3% RP has the potential to enhance egg quality by partially modulating serum antioxidant status, jejunal barrier function, and cecal microbiota structure and metabolites, indicating that RP could be considered a promising feed additive to promote the production performance of late-phase laying hens.

It has been found that thymol (Thy) and rosmarinic acid (Ros-A) improve the growth performance of piglets and relieve intestinal inflammation in animals. The effects of Thy and Ros-A separately or in combination (Thy × Ros-A) on the intestinal function and health of piglets challenged with Escherichia coli K88 (E. coli K88) were investigated. A total of 30 piglets aged 21 d were assigned to 5 groups (n = 6). The control (Con) and K88 groups piglets received a basal diet, while the Thy, Ros-A, and Thy × Ros-A groups were fed a basal diet supplemented with 500 mg/kg Thy, 500 mg/kg Ros-A, and 250 mg/kg Thy + 250 mg/kg Ros-A, respectively. On the 19th and 20th day, piglets in the K88, Thy, Ros-A, and Thy × Ros-A groups were orally administered 10 mL of phosphate-buffered saline (PBS) containing approximately 1 × 10⁹ CFU/mL of E. coli K88, while the Con group received an equal volume of PBS. The results showed that the Thy × Ros-A treatment reduced the damage to ileal villi induced by the E. coli K88 challenge, leading to longer villi in the ileum (P < 0.05). Thy and Ros-A modulated the composition of the ileal microbiota. Compared to the K88 group, the Thy × Ros-A group had a higher abundance of Lactobacillus and Romboutsia, while Escherichia-Shigella and Desulforvibrio were lower (P < 0.05). Additionally, the Thy × Ros-A group showed elevated levels of gene and protein expressions for zonula occludens-1, occludin, and claudin-1 compared to the K88 group (P < 0.05). In conclusion, combining Thy and Ros-A reduced ileal damage and relieved the inflammation in weaned piglets challenged with E. coli K88 by regulating intestinal microflora and improving barrier function.

This study investigated the effect of peroxidized lipids on piglets' growth performance, intestinal morphology, inflammatory reactions, oxidative stress in the liver, duodenum, jejunum, ileum, and colon, and ileal microbiota. Twenty piglets (Duroc × [Landrace × Yorkshire]; age = 21 d old, BW = 6.5 ± 1 kg) were randomly assigned to two groups with 10 replicates per group and one piglet per replicate. The control group was fed 6% fresh soybean oil and the peroxidized soybean oil (PSO) group fed 6% PSO. The experimental feeding period lasted 24 d. The study found no impact on ADFI, ADG and gain to feed ratio (P > 0.05). However, the PSO group increased the diarrhea index and the serum levels of lactate dehydrogenase triglycerides, cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (P < 0.05), along with decreased concentrations of alanine aminotransferase and blood urea nitrogen (P < 0.05). For oxidative enzymes, PSO increased the concentration of F2-isoprostane in urine (P = 0.032), malondialdehyde (MDA) in the duodenum (P = 0.001) and jejunum (P = 0.004), decreased thiobarbituric acid reactive substances (TBARS) in the liver (P = 0.001) but increased TBARS in duodenum (P = 0.001), and carbonylated proteins in the duodenum (P = 0.003). For antioxidant enzymes, PSO decreased superoxide dismutase (SOD) in the liver (P = 0.001), colon (P = 0.002), and jejunum (P = 0.015), along with glutathione peroxidase (GSH-Px) in the liver (P = 0.008) and NAD(P)H:quinone oxidoreductase 1 (NQO1) in ileum (P = 0.001). For inflammatory reactions, PSO increased interleukin (IL)-1β concentrations in the duodenum and colon, and IL-10 in the jejunum, while decreasing IL-4 concentration in the duodenum (P < 0.05). For intestinal morphology and ileal microbiota, PSO increased ileal crypt depth, while decreasing the crypt-to-villus ratio (P < 0.05). Peroxidized soybean oil increased the relative abundance of Prevotella, Clostridium_sensu_stricto_1, Clostridium_sensu_stricto_6, Pasteurella and Klebsiella (P < 0.05). In conclusion, this study revealed that PSO worsened diarrhea, increasing the ileal crypt depth and the relative abundance of harmful microbiota, and induced oxidative stress and inflammation in the intestines and liver, primarily in the jejunum and ileum.

This study investigated the effects of β-alanine (β-Ala) on rumen fermentation, nutrient digestibility, nitrogen (N) metabolism, plasma biochemical parameters, and rumen bacterial communities in beef steers. Six steers with initial liveweight of 252.8 ± 5.2 kg and 3 treatments of supplementing with 0, 30, or 60 g β-Ala per day to basal diet were allocated in a replicated 3 × 3 Latin square design. Each experimental period was 20 d, of which the first 15 d were for adaptation and the subsequent 5 d were for sampling. The results showed that β-Ala linearly increased the ruminal concentration of microbial crude protein (MCP) (P = 0.005), but it did not affect the ruminal concentrations of ammonia N and total volatile fatty acids (P > 0.10). β-Ala also linearly increased the dry matter (DM) (P = 0.009), organic matter (OM) (P = 0.017) and crude protein (CP) (P = 0.043) digestibility, tended to decrease the acid detergent fiber digestibility (P = 0.077), but it did not affect the neutral detergent fiber digestibility (P = 0.641). β-Ala quadratically increased the relative abundance of ruminal Bacteroidota (P = 0.021) at the phylum level, and increased Prevotella (P = 0.028) and Prevotellaceae_UCG-003 (P = 0.014), and decreased the relative abundance of NK4A214_group (P = 0.009) at the genus level. Feeding steers with β-Ala linearly increased the urinary N (P = 0.006), urea excretions (P = 0.002) and the N retention (P = 0.004), but it did not affect the N utilization efficiency (P = 0.120). β-Ala quadratically increased the plasma concentration of the total antioxidant capacity (P = 0.011) and linearly increased the plasma concentration of insulin-like growth factor-1 (P < 0.001). In summary, dietary supplementation with β-Ala improved the rumen MCP supply and increased the digestibility of DM, OM, CP and the N retention. Further research is necessary to verify the ruminal degradability of β-Ala and to investigate the mechanism of the impact of absorbed β-Ala on the anti-oxidative ability in steers.

The reduced nutrient digestibility of low-protein (LP) diets has been shown to be caused by the weakened fermentative capacity of the post-gut flora. The dynamic regulation of dietary protein contents on post-gut microbial population and fermentative metabolism is unclear. Twelve growing barrows (19.9 ± 0.8 kg) fitted with a T-cannula at the blind end of the cecum were randomly administered a high-protein (HP, 21.5% crude protein [CP]) diet or an LP (15.5% CP) diet for 28 d. The cecal content and feces were collected at d 1, 14, and 28 of the experiment for microflora structures and metabolite concentrations analysis. The nutrient digestibility coefficient and plasma biochemical parameters were also determined. Compared with the HP treatment, the LP treatment showed decreased plasma urea nitrogen concentration and apparent total tract digestibility of dry matter, gross energy, and CP (P < 0.01). In addition, urinary nitrogen losses, total nitrogen losses, and daily nitrogen retention in the LP treatment were lower than those in the HP treatment (P < 0.01), and the nitrogen retention-to-nitrogen intake ratio in the LP treatment was increased (P < 0.01). The HP group showed increased cecal total short-chain fatty acids (SCFA) concentration and fecal propionate, butyrate, and total SCFA concentrations (P < 0.05) on d 14 and 28, which may be mainly related to the elevated abundance of SCFA-producing bacteria, such as Ruminococcus, Lactobacillus, and Prevotella (P < 0.05). Probiotics, such as Bifidobacterium, Bacteroidales S24-7, and Rikenella, enriched in the LP treatment possibly contributed to reduced plasma endotoxin content. The differences in the abundances of almost all the above-mentioned flora appeared on d 28 but not d 14. Likewise, differences in the Simpson and Shannon indices and clustering patterns of the microbiota between treatments were also only observed on d 28. To sum up, in a time-dependent manner, the LP diet increased probiotics with gut-improving functions and decreased SCFA-producing bacteria, which may cause enhanced intestine health and reduced nutrient digestibility.