Amphibians Guidelines for the Breeding, Care and Management of Laboratory Animals (1974) / Chapter Skim
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VII Breeding
VII Breeding
Pages 95-107
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From page 95... ...
Laboratory-reared or laboratory~bred specimens may be in a physiological state allowing ovulation at any time. Artificial insemination using species that normally mate some weeks after hibernation has been accomplished only in the days immediately before the time of natural breeding.
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From page 96... ...
Kits including pituitary preparations plus directions for fertilizing eggs are available from commercial dealers. However, pituitaries are readily collected following the technique described by Rugh (1965~.
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From page 97... ...
After sperm activity has been confirmed, eggs are stripped from the female (Figure 23) by holding her in such a manner that pressure is applied to her abdomen with the force directed toward her cloaca, thus squeezing the eggs from the ovisacs into a dry Petri dish.
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From page 98... ...
A singleedge razor blade, tissue section lifter, scalpel, or glass slide should be used for this: Do not attempt to pull the eggs from the Petri dishes with fingers or forceps as they may be distorted and thus damaged. About 1 h after fertilization those eggs successfully fertilized will rotate so the black animal hemisphere is uppermost.
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From page 99... ...
. The procedure for artificial insemination described here is applicable to any type of mating involving biparental reproduction (e.g., random mating lines, heterozygous marked lines, mutant lines)
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From page 100... ...
Homozygous diploids can be produced by the nuclear transplantation method (see Chapter III, Section C.1.g and Chapter VII, Section A.9~. These homozygous diploids, as other homozygous individuals, show reduced viability (Subtelny, 1958~.
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From page 101... ...
8. Mosaic Animals Application of the pressure technique to inhibit cytokinesis at the second or third or combination of cleavage stages can produce mosaic animals.
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From page 102... ...
. The administration of human chorionic gonadotropin to mature males resulted in the appearance of black nuptial pads on the inner aspects of the forelimbs but did not noticeably affect the viability or fertilizability of the resulting sperm suspensions and, therefore, was not routinely employed.
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From page 103... ...
Estimates of sperm concentration were made from hemacytometer counts and the average value of 25 X 106 cells/ml was obtained for sperm suspensions resulting from the maceration of one pair of testes in 10 ml of buffer. Artif cial Insemination Artificial insemination was conducted in watchglasses (3 - inch diameter)
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From page 104... ...
The spermatophores consist of an almost transparent base, are roughly pyramidal in shape, and are constructed of a gel-like material secreted by certain of the cloacal glands. This base is capped by an opaque white mass of spermatozoa that may freely project in cylindrical form.
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From page 105... ...
Sometimes many normal spermatophores may be found after a mating yet all the eggs laid may be infertile; ovulation in such cases must have been induced by the stimulus of the courtship or possibly by a mechanical stimulation of the cloaca. While spawning, the female may be gently transferred to a fresh enclosure with a clean glass, slate, or enameled bottom.
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From page 106... ...
Using two pairs of small forceps, tear open the oviduct, starting at its cloacal end. With the forceps, transfer groups of eggs to clean dry Syracuse watch glasses or small Petri dishes.
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From page 107... ...
4. Initial Care of Embryos Eggs obtained either by artificial insemination or from natural spawning require chlorine-free water.
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