Sperm cryopreservation is one of the sublime biotechnologies for assisted reproduction. In recent decades, there has been an increasing trend in the use of preserved semen. Post-thaw semen quality and values vary among animals of the same species. Similarly, there are species-specific variations in sperm morphology, i.e., sperm head, kinetic properties, plasma membrane integrity, and freezability. Similarly, the viability of sperm varies in the female reproductive tract, i.e., from a few hours (in cattle) to several days (in chicken). Various steps of sperm cryopreservation, i.e., male health examination, semen collection, dilution, semen centrifugation, pre- and post-thaw semen quality evaluation, lack standardized methodology, that result in differences in opinions. Assisted reproductive technologies (ART), including sperm preservation, are not applied to the same extent in commercial poultry species as in mammalian species for management and economic reasons. Sperm preservation requires a reduction in physiological metabolism by extending the viable duration of the gametes. Physiologically and morphologically, spermatozoa are unique in structure and function to deliver paternal DNA and activate oocytes after fertilization. Variations in semen and sperm composition account for better handling of semen, which can aid in improved fertility. This review aims to provide an update on sperm cryopreservation in farm animals.

Introduction: The Dezhou donkey, a prominent Chinese breed, is known for its remarkable size, rapid growth, and resilience to tough feeding conditions, and disease resistance. These traits are crucial in meeting the growing demand for Ejiao and donkey meat. Yeast polysaccharide (YPS), a functional polysaccharide complex known for its immune-enhancing and growth-promoting properties in livestock and poultry, remains relatively understudied in donkeys.Objectives: This study aimed to investigate the impact of YPS supplementation on lactating and growing Dezhou donkey jennies and foals.Materials and methods: Twelve 45-day-old Dezhou donkey foals and their jennies, matched for body weight and age, were randomly allocated to two dietary groups: a control group receiving a basal diet and an experimental group receiving the basal diet supplemented with 10 g/pen of YPS. The experiment was conducted over a 23-day period, during which donkey foals and lactating jennies were co-housed.Results and discussion: The findings revealed that YPS supplementation had no adverse effects on milk production or composition in Dezhou donkey jennies but significantly increased feed intake. Additionally, YPS was associated with increased plasma glucose and creatinine concentrations in foals, while tending to decrease alkaline phosphatase, white blood cell count, red blood cell count, and hemoglobin levels (p < 0.10). Immune indices demonstrated that YPS supplementation elevated the levels of immunoglobulin A (IgA) and immunoglobulin G (IgG) in jennies (p < 0.05) and increased complement component C4 concentrations in foals (p < 0.05). Moreover, YPS positively influenced the fecal microbiome, promoting the abundance of beneficial microorganisms such as Lactobacillus and Prevotella in donkey foals and Terriporobacter and Cellulosilyticum in jennies, all of which contribute to enhanced feed digestion. Additionally, YPS induced alterations in the plasma metabolome for both jennies and foals, with a predominant presence of lipids and lipid-like molecules. Notably, YPS increased the concentrations of specific lipid metabolites, including 13,14-Dihydro PGF2a, 2-Isopropylmalic acid, 2,3-Dinor-TXB2, Triterpenoids, Taurocholic acid, and 3b-Allotetrahydrocortisol, all of which are associated with improved animal growth.Conclusion: In conclusion, this study suggests that dietary supplementation of YPS enhances feed intake, boosts immunity by increasing immunoglobulin levels, stimulates the growth-promoting gut microbiota (Lactobacillus and Prevotella), and exerts no adverse effects on the metabolism of both Dezhou donkey jennies and foals.

Donkey milk has received increasing attention in recent years due to its unique nutritional composition and potential biological activities. This comprehensive review analyzed the main nutritional components of donkey milk, including proteins, lipids, carbohydrates, vitamins, and minerals, while also examining its significant biological activities such as antioxidant, antimicrobial, immunomodulatory, and anti-inflammatory properties. The protein profile of donkey milk is notable for its high proportion of whey proteins (55–65%), resembling human milk more closely than cow milk. Its relatively low-fat content (approximately 1.29%) with higher proportions of unsaturated fatty acids provides nutritional advantages for specific dietary needs. The carbohydrate content, primarily lactose, contributes to energy provision and calcium absorption. Donkey milk is also distinguished by its rich vitamin profile, particularly vitamin C (about 4.75 times higher than cow milk), and essential minerals including calcium, phosphorus, and zinc. The biological activities of donkey milk extend to various applications in infant nutrition, particularly for children with cow milk protein allergies, potential medical treatments for infections and inflammatory conditions, and cosmetic formulations. Despite these promising attributes, the donkey milk industry faces challenges including low milk yield, lack of standardized production methods, and quality control measures. The sustainable development of the donkey milk industry requires comprehensive approaches to resource protection, technological innovation, brand building, and supportive policies to realize its full potential in contributing to human health and economic development.

Herbivorous animals rely on complex gastrointestinal systems and microbial communities to efficiently digest plant-based diets, extract nutrients, and maintain health. Recent advances in metagenomic technologies have enabled high-resolution, culture-independent analysis of gut microbiota composition, functional potential, and host–microbe interactions, providing insights into microbial diversity across the herbivore digestive tract. This review summarizes key findings on the gastrointestinal microbiota of herbivores, focusing on ruminant foregut and non-ruminant hindgut fermentation. Ruminants like cattle, sheep, and goats host microbiota enriched with fibrolytic and methanogenic microbes that facilitate fiber degradation and volatile fatty acid production, contributing significantly to energy balance. In contrast, non-ruminants such as horses and rabbits rely on hindgut fermentation, with distinct microbial taxa contributing to carbohydrate and protein breakdown. The review further explores how specific microbial taxa, including Prevotella, Fibrobacter, and Ruminococcus, correlate with improved feed efficiency and growth performance, particularly in ruminants. Additionally, the roles of probiotics, prebiotics, and symbiotics in modulating gut microbial composition and enhancing productivity are discussed. Despite significant advances, challenges remain in microbial sampling, functional annotation, and understanding the integration of microbiota with host physiology. The review emphasizes the potential of metagenomic insights in optimizing herbivore gut microbiota to improve feed efficiency, health, and sustainable livestock production.