Evaluation of the use of L-carnosine in short and long term storage of ram semen with spermatological and flow-cytometric analysis

This study was carried out to investigate the effect of in vitro addition of L-carnosine to semen at different doses on short and long term storability of semen. In the study, semen taken from 6 Akkaraman rams were used. In the first stage of the study, semen from each animal were mixed and diluted with tris+egg yolk extender containing 1, 5, 10, 20, 50, 100 and 200 mM L-carnosine and stored at +4°C for 96 hours. During short-term storage, doses of 1, 5, 10, 20 mM L-carnosine increased total, progressive and rapid motility, VCL, VSL, VAP values from kinematic parameters, and high mitochondrial membrane potential level. It was determined that these doses preserved membrane integrity, decreased abnormal spermatozoon rate, acrosomal damage and low mitochondrial membrane potential level. It was determined that 200 mM L-carnosine dose had a toxic effect and affected the parameters negatively. In the second stage of the study, the best doses (1, 5, 10 and 20 mM) in the first stage were used and semen collected 6 times were subjected to freezing. It was determined that 5 mM L-carnosine dose stood out in all analyzes in long-term storage of semen, and this dose significantly increased the rate of total, progressive and rapid motility, viable spermatozoa rate and high mitochondrial membrane potential. In addition, it has been determined that the spermatozoon maintains the integrity of the membrane, significantly reduces the abnormal spermatozoon rate, the rate of dead sperm, the rate of acrosomal damage, the low mitochondrial membrane potential and the apoptotic cell rate. As a result, it was determined that adding 5 mM L-carnosine to the semen extender during the freezing of ram semen would be beneficial and contribute to the successful freezing of the semen.