Poultry semen preservation is crucial for sustaining genetic diversity, improving production efficiency, and facilitating various breeding initiatives. This review underscores the importance and challenges associated with different preservation techniques. We investigate effective techniques for semen collection and evaluation, focusing on vital parameters such as volume, concentration, motility, and morphology. Preservation strategies are categorized into short-term approaches, such as dilution with extenders, and mid-to-long-term strategies, like freezing and the use of cryoprotectants. Additionally, we explore several factors affecting semen quality, including male age and genetics, seasonal impacts, and stress during handling. Assessing the quality of preserved semen is critical, particularly regarding post-thaw motility. The applications of these preservation techniques in artificial insemination, genetic enhancement, the conservation of endangered breeds, and biobanking are highlighted. This review identifies critical research opportunities, including the development of improved cryoprotectants, refining freezing protocols, comprehending the mechanisms of semen damage, and innovating novel preservation technologies. Addressing these challenges will enhance poultry semen preservation and contribute to sustainable poultry farming.

To investigate the effect of Eimeria tenella (E. tenella) infection on the cecal microbiota, resistant and susceptible families were screened out based on the coccidiosis resistance evaluation indexes after E. tenella infection. Subsequently, a comparative analysis of cecal microorganisms among control, resistant, and susceptible groups as well as between different periods following the E. tenella challenge was conducted using metagenomic sequencing technology. The results showed that the abundance of opportunistic pathogens, such as Pantoea, Sporomusa, and Pasteurella in the susceptible group and Helicobacter and Sutterella in the resistant group, was significantly higher on day 27 post-inoculation (PI) (the recovery period) than on day 5 PI (the infection period). Additionally, the abundance of Alistipes, Butyricicoccus, and Eubacterium in the susceptible group and Coprococcus, Roseburia, Butyricicoccus, and Lactobacillus in the resistant group showed a significant upward trend during the infection period compared with that in the recovery period. On day 5 PI, the abundance of Faecalibacterium and Lactobacillus was decreased in both the resistant and susceptible groups when compared with that in the control group and was greater in the resistant group than in the susceptible group, while Alistipes in the susceptible group had a relatively higher abundance than that in other groups. A total of 49 biomarker taxa were identified using the linear discriminant analysis (LDA) effect size (LEfSe) method. Of these, the relative abundance of Lactobacillus aviarius, Lactobacillus salivarius, Roseburia, and Ruminococcus gauvreauii was increased in the resistant group, while Bacteroides_sp__AGMB03916, Fusobacterium_mortiferum, Alistipes_sp__An31A, and Alistipes_sp__Marseille_P5061 were enriched in the susceptible group. On day 27 PI, LDA scores identified 43 biomarkers, among which the relative abundance of Elusimicrobium_sp__An273 and Desulfovibrio_sp__An276 was increased in the resistant group, while that of Bacteroides_sp__43_108, Chlamydiia, Chlamydiales, and Sutterella_sp__AM11 39 was augmented in the susceptible group. Our results indicated that E. tenella infection affects the structure of the cecal microbiota during both the challenge and recovery periods. These findings will enhance the understanding of the effects of changes in the cecal microbiota on chickens after coccidia infection and provide a reference for further research on the mechanisms underlying how the intestinal microbiota influence the growth and health of chickens.

Coccidiosis, caused by Eimeria protozoa, is a severe intestinal parasitic disease that results in substantial economic losses to the global poultry industry annually. The gut microbiota plays a crucial role in host health, metabolism, immune function, and nutrient absorption in chickens. Recent studies have focused on the effects of Eimeria tenella’s (E. tenella) acute infection period on host health. However, recovery conditions, cecal microbiota composition, and functional differences in the ceca of chickens with varying resistance to E. tenella remain poorly understood during the recovery period after infection. This study aimed to compare growth performance, cecal histopathology, and the cecal microbiota characteristics in control (R_JC), resistant (R_JR), and susceptible (R_JS) chickens during recovery, using metagenomic sequencing. The results revealed significant differences in both cecal tissue structure and growth performance between the different groups during recovery. Although no significant differences were observed in microbial alpha diversity among the groups, sequencing analysis highlighted notable changes in microbial composition and abundance. Bacteroidetes, Firmicutes, and Proteobacteria were the predominant phyla in chicken cecal contents; however, Firmicutes abundance was lower in the R_JS group than in the R_JC and R_JR groups. Further analysis, combining linear discriminant analysis effect size (LEfSe) and differential heatmap analysis, identified Bacteroides_fluxus, Ruminococcus_flavefaciens, and Bacteroides_sp_CACC_737 as dominant microorganisms in the R_JR group (p < 0.05) compared to both the R_JC and R_JS groups. In contrast, Sutterella_sp_AM11-39, Bacteroides_sp_43_108, Mycobacterium, Mycoplasma_arginini, and Chlamydia dominated in the R_JS group, while Butyricimonas, Butyricimonas_sp_Marseille-P3923, and Flavonifractor_plautii were significantly reduced in the R_JS group (p < 0.05). Additionally, beneficial cecal microorganisms such as Flavonifractor_sp__An10, Pseudoflavonifractor, and Faecalicoccus were significantly decreased in both the R_JR and R_JS groups (p < 0.05) compared to the R_JC group. Predictive functional analysis using the KEGG and CAZy databases further indicated that the cecal microbiota in the R_JR group exhibited enhanced metabolism-related pathways, whereas these pathways were significantly diminished in the R_JS group, potentially influencing the recovery process from coccidial infection. These findings provide valuable insights into the cecal microbiota’s role during recovery from E. tenella infection and deepen our understanding of the impact of coccidial infections on host health.

The preservation of rooster semen quality during short-term liquid storage remains a challenge in poultry reproductive biotechnology because sperm cells rapidly lose functional competence under ambient conditions. This deterioration is largely associated with oxidative stress and lipid peroxidation of sperm membranes, which are particularly vulnerable in avian species due to their high polyunsaturated fatty acid content and limited cytoplasmic antioxidant defenses. Selenium is an essential trace element involved in cellular antioxidant protection through its incorporation into several selenoproteins that regulate redox balance and protect cellular structures from oxidative injury. The present study evaluated the effects of selenium methionine supplementation on rooster semen quality during liquid storage at 25 °C. Semen was diluted using a standard poultry semen extender composed of sodium glutamate, glucose, potassium acetate, magnesium acetate, and potassium citrate. Selenium methionine was incorporated into the semen extender at concentrations of 0.5%, 1%, and 2% (w/v) at the time of semen dilution prior to storage. Semen quality was assessed at 0, 4, 8, 12, and 24 h of storage. Functional parameters, including total sperm motility, sperm viability, and dead sperm percentage, together with kinematic variables (VSL, VCL, VAP, ALH, LIN, and STR), were analyzed using computer-assisted sperm analysis (CASA). Structural integrity was evaluated through acrosome and plasma membrane integrity tests, while sperm physiological status and apoptotic progression were assessed using Annexin V-FITC/propidium iodide flow cytometry. Significant effects of storage time, selenium methionine concentration, and their interaction were observed for multiple semen quality parameters (p < 0.05). Among the tested concentrations, supplementation with 0.5% selenium methionine consistently produced the most favorable results, maintaining higher sperm motility, viability, and membrane integrity while reducing dead sperm percentage and apoptotic progression during storage, with protective effects particularly evident at 8, 12, and 24 h compared with the control and higher concentrations. Polynomial contrast analysis indicated predominantly non-linear dose–response relationships, with quadratic and cubic components providing the best model fit (R² = 0.90–0.99; p < 0.0001), suggesting a hormetic antioxidant effect. Overall, these findings indicate that selenium methionine supplementation in semen extender improves the stability of rooster semen during short-term liquid storage at ambient temperature, with 0.5% showing the most consistent protective effects among the concentrations evaluated.