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As only 10% of the broiler breeder flock is roosters, their fertility is very important. The rooster sperm plasma membrane has high concentrations of polyunsaturated fatty acids that are sensitive to oxidative stress. Lipid peroxidation can change membrane structure, permeability, and fluidity, adversely affecting the acrosome reaction and fertility. Aging roosters have decreases in sexual behavior, serum androgen concentrations, sperm quantity and quality, and fertility. Low fertility in aging roosters is attributed to an imbalanced testicular oxidant-antioxidant system, with increased reactive oxygen species (ROS) damaging spermatogenic epithelium. However, antioxidant components can enhance antioxidant defenses in aging broiler breeder roosters. Protection against oxidative damage, particularly in the testes, improves reproductive hormone concentrations, testicular histology, sperm membrane function, and mitochondrial activity and thereby improves semen volume, sperm concentration, viability, motility, and sperm polyunsaturated fatty acid content, sperm-egg penetration, fertility, and reproductive performance. This review summarizes antioxidants that could improve fertility and reproductive performance and delay or prevent age-related declines in broiler breeder roosters, with benefits for poultry production., (© 2024. The Author(s), under exclusive licence to American Aging Association.)

Laccases are appealing biocatalysts for various industrial utilizations. The fungus Trametes versicolor (L.: Fr.) Pilát causes white rot in wood and has been identified as an important fungal laccase producer. To investigate laccase production and activity in T. versicolor, the native isolate was collected from the host (Quercus castaneifolia) in the forests of Guilan province, northern Iran, and then purified and identified using the molecular marker. Its ability to produce laccase enzyme in the presence of different plant substrates including sawdust and wood chips of oak, poplar, and pine was evaluated. Also, the effect of copper as an enzyme inducer was investigated in vitro. The results showed that adding the wood to the culture medium increased laccase production, and among these, oak sawdust had the greatest effect, a 1.7-fold increase from that in the control (4.8 u/l vs. 2.8 u/l). Also, the enzyme extraction time effect on the optimal recovery yield showed that the 5-h enzyme extraction cycle resulted in the highest yield of the enzyme (18.97 u/l). Moreover, adding different concentrations of copper to the fungal culture medium increased the production of laccase, and the highest amount of enzyme (92.04 u/l) was obtained with 3.5 mM of CuSO 4 along with oak sawdust. Based on the results, the addition of host wood sawdust ("oak" in this work) and copper particles together stimulates the fungal growth and the laccase production during submerged cultivation of T. versicolor. Therefore, it would be a safe and cheap strategy for the commercial production of laccase by filamentous fungi., (© 2023. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)