Role of nano-dietary supplements in improving semen quality and fertility in aged roosters: physiological and molecular mechanisms, nutritional applications, and future perspectives: A review

Abstract:

Aging reduces semen quality, fertilizing capacity, and subsequent reproductive function, primarily due to oxidative stress and related mitochondrial dysfunction, lipid peroxidation, and endocrine imbalance. Testicular degeneration, chronic inflammation, and impaired spermatogenesis ultimately lead to reduced sperm concentration, motility, viability, and membrane integrity. In the past few years, nano-enabled dietary supplements have gained much attention as a potentially effective nutritional approach to ameliorate these problems in breeder roosters since their special physicochemical properties significantly improve intestinal absorption, cellular uptake, tissue distribution, bioavailability, and biological activity compared to their conventional counterparts. This review paper presents, in a critical manner, the scientific knowledge available at this time on the use of nano-dietary supplements to enhance reproductive performance in senescent roosters. Special attention is paid to selenium nanoparticles (SeNPs), nano-curcumin, and niosomal curcumin, as these are currently considered the most researched nano-formulations in poultry reproduction. Available information suggests that these nano supplements efficiently improve antioxidant defense systems, maintain mitochondrial function, decrease lipid peroxidation, enhance testicular morphology, stimulate steroidogenesis, and protect sperm plasma membranes and DNA integrity. In most cases, therefore, they have led to significantly improved sperm concentration, motility, viability, semen quality, fertility, and reproductive performance compared with conventional dietary supplements. Selenium nanoparticles generally show superior biological efficacy over inorganic selenium and, in some reproductive traits, organic selenium as well, while nano-curcumin formulations consistently outperform conventional curcumins because of their much-improved bioavailability. Although these findings are encouraging, evidence is still limited due to the relatively small number of experimental studies, variations in characteristics of nanoparticles and supplementation protocols, and inadequate information on long-term safety, optimal dosage, tissue accumulation, and commercial field application. Future research that will be able to establish and develop standardized, safe, and economically viable nano-nutritional strategies to extend reproductive lifespan and fertility of breeder roosters will be that which integrates molecular biology, reproductive physiology, nanotechnology, and precision nutrition for poultry.