In vivo male african catfish sperm obtaining and evaluation for artificial reproduction

Abstract

African catfish is a valuable unpretentious object of breeding. It is successfully grown in re-circulating aquaculture systems in mild climate areas. However, artificial reproduction of the African catfish has problems with the collecting of high-quality sperm for fertilization of eggs. Abdominal massage does not give results even after appropriate hormonal stimulation: sperm is released in a small volume, often with an admixture of urine and blood. At the same time, most spermatozoa are motionless. This is due to the morphological features of the gonad structure: the seminal tubules are of the percoid type, in which there are seminal vesicles that prevent sperm release. When breeding catfish, the method of slaughtering males is mainly used, followed by the extraction of gonads, their grinding and straining through gauze or a sieve. Therefore, an urgent task is to develop methods for in vivo male African catfish high-quality sperm collecting. This report shows the technique of gonadectomy and surgery techniques for extracting one or both gonads. General anesthesia was performed by immersing the fish in a solution of clove oil. The optimal dose of clove oil for anesthesia was determined as 0.10–0.20 ml/l. The surgical area was treated with an antiseptic solution. The skin was dissected and separated from abdominal muscles. After acutorsion of testicular vessels, the gonad was excised entirely, since with partial resection, the remaining part of the parenchyma oozes, causing inflammation of the abdominal cavity and impaired healing of the surgical wound. Intermittent octal sutures were applied separately to the peritoneum with abdominal muscles and skin to create additional anastomoses and prevent complications.