Studies on the milt quality of Common carp (Cyprinus carpio var communis) and Koi carp (Cyprinus carpio var koi).

Abstract

The objective of this study was to determine the quality of milt of the two species of fishes, Common carp (Cyprinus carpio var communis) and Koi carp (Cyprinus carpio var koi) belonging to the family Cyprinidae. The fishes were reared from fingerling size (2 cm) in the perennial pond system and they attained broodstock sizes (average weight, 300 gm) in a period of four months. The milt was collected by applying mild abdominal pressure. The volume, pH, motility, quality and cryopreservation trials were carried out. The milt samples were diluted with Cortland Medium (pH 7.56) and protected with Glycerol and DMSO (Dimethyl Sulphoxide) were used as cryoprotectants at 5%, 10% and15% concentrations. Comparative studies were also made on the effectiveness of DMSO and Glycerol as cryoprotectants. It was observed that motility rates were higher (60%) for DMSO than Glycerol (40%) at 15% concentration levels. The samples were stored in LN2 upto 60 days. The post thaw motility rates were observed based on motility rate. The equilibration periods were also studied and it was observed that motility rate was 60% for samples stored using DMSO as cryoprotectant. Among the cryoprotectants used it was also observed that DMSO proved better than Glycerol as cryoprotectant for both the samples.