Deutscher Tropentag, October 9 - 11, 2002 in Kassel-Witzenhausen "Challenges to Organic Farming and Sustainable Land Use in the Tropics and Subtropics"

Artificial Reproduction of Asian Green Catfish (Mystus nemurus): Trials to Obtain High Quality Sperm from Alive Males

Georg-August University Göttingen, Institute of Animal Husbandry and Genetics, Germany

Abstract

The Asian Green Catfish (Mystus nemurus) is a native species in South East Asia. Due to its excellent taste and dietary merits the species represents a new aquaculture candidate with a production of about 700 t/a. Although other steps of cultivation seem to be practicable getting sperm for artificial reproduction needs to be optimised. For artificial reproduction of the Asian Green Catfish ripe eggs can easily be stripped from alive females whereas sperm has to be collected from dissected testis of killed males. Getting adequate sperm from living males would be a benefit especially for selective breeding programmes, as also paternal influences could be estimated and utilised to increase the breeding progress. Therefore the aim of this study was to evaluate practicable methods to obtain sperm from alive Asian Green Catfish males. The male reproductive system of Asian Green Catfish was anatomically and morphologically examined. The testis and seminal vesicles were composed from numerous lobes connected to the posterior part of the vas deferens. Furthermore the testis lie deep in the body and are covered with other organs. This physically seems to inhibit the stripping of large quantities of milt. The GSI (mean: 0.44), from milt out of different dissected testes, the percentage of motile sperms (mean: 98%), the duration of motility (mean: 4 min) and sperm density (mean: 1.465*10¹⁰ sperms/ml) were examined. To provide best possible preconditions of testis for artificial stripping the influence of injections with different dosages of LHRHa (15-60 µg/kg BW) in combination with domperidone (5-20 µg/kg BW) on GSI and sperm density was monitored. An upward tendency of GSI in the case of increasing hormone dosages could be shown, nevertheless this trend was not significant. No significant influence of hormone dosages on sperm density could been found. Treated males (20 µg LHRHa/kg BW and 5 µg domperidone/kg BW) where artificially stripped. In half of the males a mean of 0.5 ml milt with a mean sperm density of 3,97*10⁷ sperms/ml could be stripped whereas in the other half stripping remained unsuccessful.

Keywords: Aquaculture, artificial reproduction, catfish

Contact Address: Andreas Müller-Belecke, Georg-August University Göttingen, Institute of Animal Husbandry and Genetics, Albrecht-Thaer-Weg 3, 37075 Göttingen, Germany, e-mail: amuelle5gwdg.de