Cryopreservation of flatfish sperm, 2: Artificial hybridization among flatfishes using cryopreserved sperm
2005
Saitoh, S.(Hokkaido. Inst. of Mariculture, Shikabe (Japan))
Scanning electron microscope observations on eggs of Japanese flounder (Paralichthys olivaceus), and cryopreserved spermatozoa in seven species of flatfishes, Japanese flounder, Pacific halibut (Hippoglossus stenolepis), barfin flounder (Verasper moseri), brown sole (Pleuronectes herzensteini), crest head flounder (Pleuronectes schrenki), marbled flounder (Pleuronectes yokohamae) and slime flounder (Microstomus achne). One micropyle whose average diameter was 5 to 7 microm on the surface of an egg was opened and spiral structure was observed in micropyle tunnel and many pits were present on the egg surface. The external shape of spermatozoa of seven species of flounder was closely resembled one another. The spermatozoa of those species had almost round-shaped head, a middle piece, and a long tail. Measurements of head length, head width, and tail width of each spermatozoon were done, but there was no significant difference (p0.01). The present result indicated at least these six species of flounder sperm could run through the micropyle of Japanese flounder egg. Hybridizations among flatfish were attempted by artificial insemination and chromosome manipulation technique using Japanese flounder eggs and cryopreserved flatfish sperm, but embryo forming and hatching rates were extremely low and no hybrid fish was produced.
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