Effects of melatonin administration on testicular hemodynamics, echotexture, steroids production, and semen parameters during the non-breeding season in Ossimi rams

This study was conducted to determine the influence of a single subcutaneous (SC) injection of melatonin (18 and 36 mg) on testicular hemodynamics, echotexture, plasma testosterone concentration, and sperm quality characteristics during the non-breeding season in Ossimi rams. Eighteen sexually mature, Ossimi rams were randomly allocated into two treated groups that received either 18 mg (Mel 18 group; n = 6) or 36 mg (Mel 36 group; n = 6) of melatonin powder dissolved in 1 ml corn oil (SC) and a control group (n = 6) that received 1 ml corn oil only. Blood collection and ultrasonographic assessment of the testes and supratesticular arteries were conducted immediately before treatment (W0) and once weekly for 8 successive weeks after melatonin injection (W1-W8). Resistive index (RI) and pulsatility index (PI) values were markedly decreased (P < 0.05) within Mel 36 (at W4-W8) and e Mel 18 (at W8) groups, which was not observed within the control group (P > 0.05). Testicular echogenicity was severely reduced (P < 0.05) in Mel 36 (at W4-W5) and Mel 18 (at W8) groups, which was not occurred in the control one (P > 0.05). The concentration of plasma testosterone was increased (P < 0.05) in Mel 36 (at W3-W8) and Mel 18 (at W8) groups, which was not clear for the control rams (P > 0.05). The percentage of progressively motile sperm cells was higher (P < 0.05) in Mel 36 group (at W5-W8), which was not recorded within the Mel 18 or control groups (P > 0.05).The percentages of sperm cells viability and normal morphology were higher (P < 0.05) within Mel 36 (at W6-W8) and Mel 18 (at W7-W8) groups, which was not detected within the control group (P > 0.05),In conclusion, the administration of melatonin ameliorates the testicular function via enhancing the testicular vascular irrigation, testosterone production, and sperm cells' quality parameters in Ossimi rams. So, we recommend administration of a single SC dose of melatonin (36 mg) at least one month before using rams for breeding especially out of the reproductive season. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study investigated the influence of melatonin injection on testicular hemodynamics, echotexture, plasma testosterone concentration, and sperm quality characteristics in Ossimi rams during the non-breeding season. The results showed that melatonin significantly improved testicular vascular irrigation, testosterone production, and sperm quality parameters, including motility, viability, and normal morphology. These findings suggest that melatonin administration can enhance testicular function in Ossimi rams.