The study aims at investigating the effect of preparations of two bacilli strains on laying hens and roosters. Preparations were based on the strains Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895. Several groups of roosters and hens received a preparation based on either strain, or a mixture of both, from the first day to the last day of poultry in production. These preparations improved egg production, quality of sperm production, quality/hatchery of eggs, and slowed down the reproductive aging of hens. These observations were confirmed by the mathematical model proposed herein. At the molecular level, the slowing down of aging was confirmed by a decrease in the amount of mitochondrial DNA damage. Monitoring the physiological parameters of the experimental and control groups of birds showed that live weight gain in all experimental groups was higher than in the control group, and the reproductive organs of hens were more developed. There was also an improvement in the biochemical parameters of blood, the quality of the sperm of roosters, the laying of laying hens, and the morphological and biochemical parameters of the eggs. One of the most significant results is an increase in egg fertilization and a decrease in embryo death during the first 7 days of incubation.
Keywords: egg production; poultry; reproductive aging; sperm quality.