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Effect of L-carnosine on Frozen Ram Semen Quality Evaluated by CASA and Flow-cytometry

İbrahim GÜNGÖR , Seyfettin Gür, Edanur Güler Ekmen

Abstract

Context Successful freezing of ram semen has not yet reached the desired levels. The main reason for this situation could be due to the fact that the spermatozoa of this species have a different lipid composition compared to other species. Aims The objective of the study was to evaluate the effect of different concentrations of L-carnosine added to the extender on ram semen after being frozen and thawed. Methods Semen was collected from six Akkaraman rams twice a week for a period of three weeks. Pooling was performed at each time. The semen were reconstituted with a pre-prepared tris+egg yolk solution and different amounts of L-carnosine to form experimental groups (Group 1: 1 mM, Group 2: 5 mM, Group 3: 10 mM, Group 4: 20 mM, Group 5: control) and were drawn into 0.25 ml mini straws. Subsequently, the samples were subjected to freezing using an automated freezing device. Following the freezing process, the straws were placed in containers containing liquid nitrogen and thawed after 24 hours. Key results After thawing, it was found that the samples containing 5 mM L-carnosine had superior results in all analyses. This concentration exhibited significantly higher percentages of progressive, total, and rapid sperm motility, live spermatozoa, high mitochondrial membrane potential rate, and higher GSH-Px levels. In addition, it was determined that 5 mM L-carnosine group protected the membrane integrity and significantly decreased the rate of abnormal spermatozoa, acrosomal damage rate, low mitochondrial membrane potential and apoptotic cell rate. Conclusions As a result, It was determined that adding 5 mM L-carnosine to the semen extender during the freezing of ram samples would be beneficial for successful freezing. Implications The addition of 5 mM L-carnosine to ram semen extenders ensures the freezability of the semen of this species, thus this protocol could be used to perform artificial insemination with frozen ram semen.

AN24048  Accepted 03 July 2024

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