This study investigated the effects of dietary mannan oligosaccharide (MOS) supplementation on growth performance, serum biochemistry, metabolomic profiles, and fecal microbiota in lactating Dezhou donkeys. Sixteen healthy jennies and their foals were randomly allocated to a control group (MCON), a group receiving no MOS, or an MOS-supplemented group (MMO; 0.5 g/kg diet) for 60 days. Compared with the MCON group, the MMO group showed a mitigation of lactational weight reduction, improved serum protein profiles, and favorable modulation of lipid metabolism. Furthermore, serum metabolomic analysis revealed 102 differentially abundant metabolites, which were enriched in 17 KEGG pathways involved in energy metabolism, bile secretion, and anti-inflammatory signaling. Key metabolites such as L-4-Chlorotryptophan, Gly-Trp, and cholylthreonine indicated enhanced nutrient metabolism and gut barrier function. Moreover, MOS supplementation significantly increased alpha diversity of the gut microbiota, altered community composition, and promoted the abundance of beneficial genera, including Clostridium and Bacteroides. Collectively, these results demonstrate that MOS supplementation improves metabolic health, modulates immune and antioxidant responses, and fosters a beneficial gut microbial ecosystem in lactating donkeys, suggesting its potential as an effective prebiotic in equine nutrition.

Acidifiers are functional feed additives that may improve egg quality by modulating intestinal microbiota and host metabolism. This study investigated the effects of dietary acidifier supplementation on laying performance, yolk fatty acid composition, eggshell ultrastructure, intestinal function, cecal microbiota, serum metabolome, and antioxidant status in laying hens. Sixty 52-week-old Jingfen No. 6 laying hens were randomly assigned to either a control group or an acidifier-supplemented group for 6 weeks. Acidifier supplementation increased laying rate and egg mass while reducing the feed-to-egg ratio. It also increased the concentrations of seven yolk fatty acids, including tetradecanoic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, cis-vaccenic acid, and arachidic acid. In addition, acidifier supplementation resulted in a denser eggshell microstructure, improved cecal mucosal morphology, and enhanced the activities of lipase, chymotrypsin, amylase, and trypsin. Although cecal microbial alpha diversity remained unchanged, acidifier supplementation altered the overall microbial community structure and enriched several genera, including Slackia_A, Megasphaera_A, Veillonella_A, Merdimonas, and Caccocola. Serum metabolomic analysis identified 395 differential metabolites, primarily associated with lipid, amino acid, energy, and bile acid metabolism. Representative altered metabolites included taurodeoxycholic acid 3-glucuronide, LysoPE (0:0/20:0), 15-HETE, cholic acid, malic acid, and succinic acid. Acidifier supplementation also favorably affected serum HDL-C, LDL-C, and calcium concentrations and enhanced antioxidant capacity. Collectively, these findings indicate that dietary acidifier supplementation improves laying performance, yolk fatty acid deposition, eggshell structure, intestinal function, and antioxidant status, accompanied by alterations in cecal microbiota and serum metabolism. These coordinated changes may contribute to the observed improvements in egg quality.

Yeast hydrolysate (YH) has attracted increasing interest as a functional feed additive because of its potential benefits for maternal nutrition and offspring development. However, its effects on milk composition and the physiological responses of donkey foals remain poorly understood. This study evaluated the effects of dietary YH supplementation in lactating Dezhou jennies on milk composition, as well as growth performance, serum biochemical parameters, and fecal microbiota in their foals. Sixteen healthy jennies and their foals were randomly assigned to a control group (OCON) or a YH-supplemented group (OYE; 0.5 g/kg diet) for 60 days. Maternal dietary YH supplementation significantly increased milk fat and milk protein contents. Foals in the OYE group showed a tendency toward greater back skin thickness, although the difference was not statistically significant, while body weight and neck skin thickness were unaffected. Serum biochemical analysis showed increased HDL-C and total cholesterol concentrations together with decreased triglyceride and LDL-C concentrations in the OYE group. In addition, serum ALT activity was significantly decreased, whereas AST levels were significantly increased. Fecal microbiota analysis indicated that YH supplementation did not significantly affect overall microbial diversity but altered the relative abundance of several bacterial taxa, including Prevotella, Alistipes, and Olsenella. Overall, maternal dietary YH supplementation was associated with changes in milk composition, selected serum biochemical parameters, and the relative abundance of specific fecal bacterial taxa in donkey foals. However, no significant improvement in offspring growth performance was observed, and the underlying mechanisms require further investigation.

This study evaluated the effects of dietary selenium-enriched Bacillus subtilis (HBS) supplementation on laying performance, egg quality, and responses to lipopolysaccharide (LPS) challenge. A total of 120 Jinghong-1 laying hens received a basal or HBS-supplemented diet for 12 weeks. Subsequently, hens within each dietary replicate were allocated to phosphate-buffered saline (PBS)- or LPS-injected subgroups, and one hen per subgroup was sampled 12 h after injection, yielding six sampled hens per treatment combination. HBS supplementation reduced the feed-to-egg ratio (1.96 vs. 2.15, p = 0.023) and increased albumen height (7.17 vs. 6.60 mm, p = 0.003) and Haugh unit (83.01 vs. 78.65, p = 0.001). Compared with LPS, HBS+LPS showed lower serum IL-1β concentrations, higher CAT and T-SOD activities, greater jejunal villus height and villus height-to-crypt depth ratio, and higher expression of selected antioxidant- and tight-junction-related genes. Jejunal cytokine responses varied among genes. No significant differences in the measured cecal alpha-diversity indices were detected, whereas exploratory LEfSe analysis identified several treatment-associated taxa. Cecal butyrate concentration was higher in HBS than in CON, with no significant difference between HBS+LPS and LPS. Collectively, these findings indicate that HBS supplementation improved feed utilization and albumen quality and was associated with changes in selected antioxidant, inflammatory, and intestinal responses following LPS challenge. The contributions of selenium and B. subtilis could not be distinguished.