title: Sperm cryopreservation of the Indian major carp, Labeo calbasu: effects of cryoprotectants, cooling rates and thawing rates on egg fertilization.
abstract: A sperm cryopreservation protocol for the Indian major carp, Labeo calbasu, was developed for long-term preservation and artificial fertilization. Milt collected from mature male fish were placed in Alsever's solution (296mOsmolkg(-1)) to immobilize the sperm. Cryoprotectant toxicity was evaluated by motility assessment with dimethyl sulfoxide (DMSO) and methanol at 5, 10 and 15% concentrations. DMSO was more toxic at higher concentrations than methanol, and consequently 15% DMSO was excluded from further study. A one-step cooling protocol (from 5 to 80°C) with two cooling rates (5 and 10°C/min) was carried out in a computer-controlled freezer (FREEZE CONTROL(®) CL-3300; Australia). Based on post-thaw motility, the 10°C/min cooling rate with either 10% DMSO or 10% methanol yielded significantly higher (P=0.011) post-thaw motility than the other rate and cryoprotectant concentrations. Sperm thawed at 40°C for 15s and fresh sperm were used to fertilize freshly collected L. calbasu eggs and significant differences were observed (P=0.001) in percent fertilization between cryopreserved and fresh sperm as well as among different sperm-to-egg ratios (P=0.001). The highest fertilization and hatching rates were observed for thawed sperm at a sperm-to-egg ratio of 4.1×10(5):1. The cryopreservation protocol developed can facilitate hatchery operations and long-term conservation of genetic resources of L. calbasu.
authors.affiliation: Department of Fisheries Biology and Genetics, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh. zaman_nahid@yahoo.com
authors.forename: Md
authors.initials: M
authors.lastname: Nahiduzzaman
authors.forename: Md Mahbubul
authors.initials: MM
authors.lastname: Hassan
authors.forename: Pankoz Kumar
authors.initials: PK
authors.lastname: Roy
authors.forename: Md Akhtar
authors.initials: MA
authors.lastname: Hossain
authors.forename: Mostafa Ali Reza
authors.initials: MA
authors.lastname: Hossain
authors.forename: Terrence R
authors.initials: TR
authors.lastname: Tiersch
mesh_terms: D000818:Animals; D002347:Carps / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D008297:Male; D010063:Ovum / Q000502:physiology*; D012662:Semen Preservation / Q000662:veterinary*; D013084:Sperm-Ovum Interactions / Q000502:physiology
chemical_list: D003451:Cryoprotective Agents