Junhong Zhu

Oxidative stress constitutes a key restrictive factor that undermines growth performance, reproductive efficiency and meat quality throughout the entire production cycle of commercial pig herds. Vitamin A (VA), an essential fat-soluble nutrient for pigs, fulfills dual antioxidant regulatory functions: it directly scavenges free radicals, and indirectly mediates transcriptional regulation of antioxidant processes via retinoic acid receptor-associated signaling pathways. By integrating recent in vivo feeding trial data and in vitro molecular experimental evidence, this review demonstrates that the antioxidant effect of VA in pigs is characterized by significant stress dependence, dose responsiveness and physiological stage specificity. Under stress challenge conditions, VA can significantly upregulate the body’s antioxidant response, while its regulatory effect is relatively weak under non-stress basal physiological conditions. From the mechanistic perspective, all-trans retinoic acid (ATRA) bound to RAR/RXR receptors can exert synergistic effects with the Nrf2 antioxidant pathway when VA is supplied at physiological nutritional doses, whereas high pharmacological doses of ATRA may induce competitive inhibitory crosstalk. It should be noted that most existing direct promoter-binding evidence is derived from cell line models rather than in vivo porcine tissue samples. For weaned piglets, an optimal dietary VA level can alleviate oxidative damage and intestinal barrier impairment induced by weaning stress, but excessive VA supplementation will trigger lipotoxic oxidative disturbance. In growing-finishing pigs, appropriate VA supplementation can increase glutathione (GSH) content in skeletal muscle and improve the lipid oxidation stability and color stability of pork during post-mortem storage; however, supra-nutritional VA will compete with vitamin E for tissue deposition, which may in turn impair the storage quality of pork. For sows, most existing studies on the reproductive antioxidant effect of VA are derived from intramuscular injection trials, and data from practical dietary VA intervention studies are still insufficient. Existing evidence indicates that maternal VA can regulate the transfer of retinol to offspring via the placenta and colostrum-milk, but no consistent dose-response relationship has been confirmed to date. Meanwhile, relevant research in breeding boars remains extremely insufficient. In terms of nutrient interaction, VA shows antioxidant synergistic effects with vitamin E, vitamin C and selenium, while excessive intake of dietary vitamin D, copper or zinc will reduce the bioavailability of VA and weaken its antioxidant protective effect. Current research in this field is constrained by prominent inter-study heterogeneity, insufficient verification of in vivo molecular mechanisms in pigs, and the absence of antioxidant-targeted VA feeding standards adapted to diverse stress scenarios. The systematic summary of the above findings provides an important reference for the formulation of precision antioxidant nutritional strategies for commercial pig herds. To address the current knowledge gaps, future research should focus on constructing standardized porcine experimental stress models, applying multi-omics technical means to dissect tissue-specific VA antioxidant regulatory networks, clarifying the mechanism of maternal-offspring VA transfer under graded dietary VA intake, and optimizing compatible dosage forms and nutrient combinations adapted to on-farm application scenarios. The advancement of related research will help alleviate production losses caused by oxidative stress and promote the construction of healthy pig production systems.

With the continuous improvement of genetic selection in modern swine production, litter size has steadily increased. However, due to the limited capacity of sows to enhance milk production, some piglets experience insufficient milk intake and restricted growth during the lactation period. As an important supplement to sow milk, artificial milk has been widely used in both production practice and scientific research. This review summarizes the effects of artificial milk on the growth performance and intestinal health of suckling piglets. It analyzes how insufficient milk yield and the nutritional composition of sow milk affect piglet growth, and then discusses the positive roles of artificial milk in alleviating the lactational burden on sows, mitigating environmental stress, and improving weaning weight and survival rate of piglets. Furthermore, the potential mechanisms by which artificial milk promotes intestinal development and enhances growth performance are examined from the perspectives of intestinal morphology, digestive function, and the mechanical, mucus, microbial, and immune barriers of the gut. This review aims to provide a theoretical basis for the management of piglets born to sows with extremely large litters.

Yucca schidigera extract (YSE) is a plant-derived feed additive rich in steroidal saponins, polyphenols, and polysaccharides, with demonstrated anti-inflammatory, antioxidant, antibacterial, and ammonia-binding properties. This review systematically synthesizes the major bioactive components, core mechanisms of action, including modulation of the Nrf2/ARE and NF-κB pathways, regulation of ruminal fermentation and ammonia-nitrogen metabolism, and maintenance of intestinal barrier integrity, and the species-specific application effects of YSE in pigs, poultry, ruminants, and aquatic animals. Most studies have shown that YSE can improve growth performance, reproductive efficiency, and product quality while concurrently reducing ammonia and methane emissions. However, the magnitude and consistency of these benefits vary considerably across species, dosage, and experimental conditions, with most evidence derived from controlled trials rather than commercial-scale validation. By integrating cross-species dose–response data and identifying critical knowledge gaps, including product standardization, long-term safety, and economic feasibility under commercial conditions, this review provides a theoretical and practical foundation for the evidence-based application of YSE as a sustainable feed additive. In the context of global efforts to reduce antibiotic use and mitigate environmental pollution from livestock production, YSE represents a promising, multifunctional tool for advancing ecological and low-carbon animal husbandry.

This research systematically compared the jejunum morphology, antioxidant capacity, barrier-related gene expression, and mucosal immune status between two Yunnan local pig breeds, namely Dahe pigs (DH) and Dahe black pigs (DHB), using histopathological staining, antioxidant assays, quantitative polymerase chain reaction (qPCR), immunofluorescence, and enzyme—linked immunosorbent assay (ELISA). The outcomes indicated that DHB presented a shallower crypt depth and a higher ratio of villus height to crypt depth, suggesting an enhanced capacity for nutrient absorption. In their jejunum, the activities of glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) were significantly elevated, whereas the levels of malondialdehyde (MDA) were notably reduced. Conversely, DH displayed superior barrier function, with significantly higher expression levels of tight-junction proteins (Occludin, OCLN; Claudin-1, CLDN1 and Claudin-2, CLDN2) , mucin genes ( MUC1 ), defense-related proteins ( DEFB1, DEFB2 ), and immune-related genes (Interleukin-10, IL-10; Toll-like receptor 4, TLR4; Myeloid differentiation factor 88, MyD88; Immunoglobulin heavy chain A, IGHA; Joining chain, JCHAIN and Polymeric immunoglobulin receptor, PIGR ), along with a significant increase in IgG levels ( p < 0.05). These findings uncover the distinct physiological and immunological characteristics between the two breeds, offering theoretical underpinnings for precision nutrition and healthy breeding strategies in local pig populations.

To mitigate antimicrobial resistance and drug residues, the use of growth-promoting antibiotics in livestock has been prohibited, prompting interest in safe natural alternatives. Lanping black-boned sheep, an indigenous high-altitude breed in Yunnan, exhibit unique physiological traits but relatively low feed efficiency. This study evaluated the effects of three natural additives—guanidinoacetic acid (GAA, 1 g/sheep/day), Ampelopsis grossedentata flavonoids (AGF, 1 g/sheep/day), and 5,6-dimethylbenzimidazole plus cobalt (5,6-DMB + Co; 100 mg 5,6-DMB + 0.5 mg Co/sheep/day)—on serum biochemistry and rumen microbiota in twenty-four Lanping black-boned sheep fed under grazing conditions for 90 days following a 10-day adaptation period. GAA and 5,6-DMB + Co increased serum globulin (p < 0.05), whereas AGF reduced urea concentrations (p < 0.05). Only GAA decreased ruminal pH (p < 0.05). All additives enhanced microbial richness (p < 0.05), with 5,6-DMB + Co inducing the most pronounced community restructuring. Taxonomically, AGF and 5,6-DMB + Co decreased Firmicutes and enriched Verrucomicrobiota, while AGF uniquely increased Cyanobacteria. GAA selectively reduced Quinella, AGF decreased Christensenellaceae_R-7_group and NK4A214_group, and 5,6-DMB + Co markedly enriched Rikenellaceae_RC9_gut_group (p < 0.05). Microbial shifts were closely associated with biochemical indices, including positive associations of Prevotella with AST and Rikenellaceae_RC9_gut_group with total protein (p < 0.05). Overall, GAA mainly affected protein-related indices, AGF lowered serum urea, and 5,6-DMB + Co increased within-sample diversity with accompanying community reweighting, providing a theoretical basis for developing sustainable feeding strategies to enhance both productivity and health in Lanping black-boned sheep.

Growth stage is a key factor influencing the composition and richness of the porcine gut microbiota. The stage-specific alterations in gut microbiota of indigenous Chinese pig breeds and cultivated breeds remain to be elucidated. This study conducted 16S rRNA sequencing analysis on fecal microbiota from Dahe black pigs across distinct growth stages. Samples included lactating sows, suckling piglets, weaned piglets, pigs weighing 50–100 kg, pigs weighing 120–150 kg, and pigs weighing > 200 kg. The results indicated that Escherichia shigella (12.4% vs. 16.2%), Lactobacillus (5.9% vs. 6.3%), and Rikenellaceae RC9 gut group (3.9% vs. 4.2%) were dominant genera shared between lactating sows and suckling piglets. The relative abundance of Eubacterium brachy group was significantly higher in lactating sows, whereas Flavonifractor was significantly lower compared to suckling piglets (p < 0.05). Compared to pigs weighing > 120 kg, lactating sows exhibited 22 differentially abundant genera, including Escherichia shigella, Cloacibacillus, Fusobacterium, Faecalibacterium, and Prevotella (p < 0.05). In suckling piglets, Firmicutes and Bacteroidota constituted 47.4% and 27.3% of the microbiota, respectively. Their relative abundance increased with body weight, reaching 52.6% and 33.3% in pigs weighing > 200 kg. Proteobacteria decreased from 17.3% in suckling piglets to 2.0% in >200 kg pigs. Spirochaetota declined from 2.5% in suckling piglets to 0.9% in weaned piglets and then increased to 6.9% in >200 kg pigs. Lactobacillus peaked at 15.7% in weaned piglets, while Escherichia shigella reached its maximum (16.2%) in suckling piglets, both gradually declining thereafter. Streptococcus abundance remained relatively stable (1.1% in suckling piglets; 4.5% in weaned piglets). Prevotellaceae NK3B31 group registered 2.9% in suckling piglets, increased to 7.1% in weaned piglets, and then declined to 2.6% in >200 kg pigs. Mitsuokella, Bilophila, Succinivibrio, Romboutsia, and Desulfovibrio were identified as the top five genera discriminating suckling and weaned piglets. Similarly, Lachnospiraceae XPB1014 group, Clostridium sensu stricto 1, Turicibacter, Quinella, and p 1088 a5 gut group were key discriminators between weaned piglets and 50–100 kg pigs. These identified microbial taxa represent potential candidate targets for modulating the developmental timing of growth phases in pigs, offering possibilities for either advancing or delaying specific physiological timepoints.

Bile acids play a dual role by aiding lipid absorption and acting as signaling molecules by interacting with various receptors. Bile acids are perpetually recycled via enterohepatic circulation and are biotransformation by gut microbiota, making bile acid metabolism a critical regulator of intestinal homeostasis. The intestinal epithelium prominently expresses two key bile acid receptors - the farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 1 (TGR5) - which play indispensable roles in maintaining bile acid homeostasis and intestinal barrier function. Due to the abundant expression of bile acid receptors and the importance of the intestine in preventing pathogen invasion, researchers are increasingly focused on the function of bile acids in this system. This article focuses on the effect of bile acids and their receptors, FXR and the TGR5, in modulating intestinal barrier function.

Background/Objectives: Panax notoginseng stems and leaves (PNSLs) have shown limited adoption as a forage component in commercial livestock operations due to low utilization rates. Methods: This study was designed to add 10% and 20% PNSLs in the diet of Duzang pigs. Hepatic tissues were collected to investigate the expression levels of Toll-like receptor (TLR), MyD88, TRIF genes, and downstream cytokines within the TLR signaling pathway. Results: 10% and 20% PNSLs in the diet significantly up-regulated mRNA expression levels of TLR3, TLR6, TLR7, TLR8, TRIF, IL-10, IFN-α and IFN-β, while they down-regulated TLR5, TLR9, TNF-α and IL-1β in Duzang pigs. No significant effects were observed on the expression of TLR2 and IL-6. Conclusions: Different amounts of PNSLs modulated the TLR signaling pathway mRNA expression levels in the hepatic tissues of Duzang pigs.