Rabbit Semen Research Articles

Proteolytic activity of human, rabbit and bull semen with special reference to peptidases in the genital tract of male rabbit.

The semen of bull, rabbit and man hydrolyses various synthetic peptides but only human semen is active on casein. An investigation of the peptidase activity of extracts from the testes, epididymis, epididymal sperm and the accessory glands of the rabbit has revealed a strong peptidase activity. Seminal plasma of vasectomized rabbits shows diminished peptidase activity as compared to normal seminal plasma. Grinding of the human or rabbit semen has no effect on the peptidase activity but grinding of bull semen increases this activity. Human semen has the highest activity with respect to all but one of the seven peptides tested. Human semen at first forms a gel which later dissolves but the gel formed from semen of rabbit does not. Bull semen does not form a gel. The stronger peptidase activity of the human semen may indicate that these enzymes play an important role in the complete breakdown of the gel forming proteins, whereas the occurrence of these enzymes in close connection to the spermatozoa in the other species suggests some role of peptidases for the metabolism of the spermatozoa or for fertilization.

I—Nigrosin-Eosin Staining of Rabbit Spermatozoa and the Fertility of Semen

SynopsisA standard nigrosin-eosin staining method in current use has been said to differentiate between live (unstained) and dead (stained) spermatozoa. In the present work, the method is applied to rabbit semen. The general results are comparable with those already obtained in the larger domestic animals. The effects of several technical and biological factors on staining capacity are evaluated, and the validity of the method is examined experimentally. Some statistical aspects are presented. The percentage of stained spermatozoa varies widely between rabbit males. To a large extent, any particular male preserves a characteristic percentage from one ejaculate to another. The percentage of stained spermatozoa is inversely related to the fertility of males as measured by the birth rate after natural mating.Concurrently, an investigation was made of the incidence of a class of morphologically abnormal spermatozoa seen in the preparations. The classifications of spermatozoa by morphology and by staining capacity are highly correlated. For assessing semen quality, the morphological classification is considered to be as useful as the classification by staining capacity, and perhaps more useful.Nigrosin-eosin staining of rabbit spermatozoa is discussed; firstly, in comparison with other animals and in relation to sources of variation; secondly, as a means of differentiating between live and dead spermatozoa; thirdly, as a means of assessing the fertility of semen; and fourthly, in relation to the alternative classification of spermatozoa by abnormal morphology.

Effects of radiocobalt irradiation of rabbit spermatozoa in vitro on fertilization and early development.

ABS>Rabbit semen irradiated with gamma radiatlon from a Co-60 source in vitro at 90 r to 65,000 r was inseminated artificially to females. The ova were examined at pronuclear, segmentation, blastocyst, and into fetal stages. The motility of spermatozoa was damaged only at very high doses of irradiation, 32,200 to 65,000 r. Though incapacity of sperm to reach the site of fertilization may occur at these dose levels, the fertilizing capaeity per se appears to be undamaged. The segmentation of fertilized ova was very much disturbed. The disturbance is in proportion to the dose level and the higher the dose level the earlier the failure of segmentation. With irradiation of sperm at 90 r, the proportion of morphologically normal fetuses is not significantly lower than after normal mating; following irradiation of sperm at 600 r the formation of normal blastocysts was impaired but once a normal blastocyst is formed implantation and development are assured; following irradiation of sperm at 6,500 r, no normal blastocyst is formed. Delayed penetration of sperm, a high proportion of polyspermic ova, haploidy and triploidy of ova, and delayed syngamy were not observed following the irradiation of sperm at 32,200 to 65,000 r. Fragmentation of femalemore » and male pronuclei, an irregularity of nucleus formation at segmentation, and one possible gynogenetic ovum out of 32 ova were observed. (auth)« less

The Effect of the Addition of l-Thyroxine to Fowl Semen

SCHULTZE and Davis (1948, 1949) and Maqsood (1950, 1954) have shown that the addition of d, l-thyroxine to bull semen increased the O2 consumption of the spermatozoa. Schultze and Davis (1949) also found an improvement in the conception rate of cows as measured by the “percentage of non-returns” when treated semen was used for artificial insemination. It had been shown earlier by Carter (1932a) that thyroxine simulates in action a secretion from ripe ova of two species of Echinus in that the spermatozoa are activated or have their life prolonged when placed in a one to 50,000 solution of thyroxine and seawater. Carter (1932b) also thought thyroxine might play an important role in higher animals and carried his experiments to the point of demonstrating that the addition of thyroxine to rabbit semen improved the O2 consumption rate of the spermatozoa of this species.Two experiments were conducted to determine the…

A study of fertilization in the rabbit: the effect of post-coital ligation of the fallopian tube or uterine horn.

SUMMARY A study was made of the effect of ligating the Fallopian tube or uterine horn near the tubouterine junction at specific time intervals after mating (½–6 hr) on fertilization in superovulated rabbits. A total of 140 does were used and altogether 2630 eggs were studied. Observations were made on the does' response to gonadotrophin treatment; the rate of egg development; the occurrence of abnormal eggs; the number of spermatozoa in fertilized eggs; the transfer of fertilized eggs to recipient does and the length of the female genital tract. Rabbit semen was collected by means of an improved type of artificial vagina. The main results following ligation were as follows: when one Fallopian tube was ligated at the time intervals stated in parentheses, the mean proportion of eggs fertilized was 1·6% (1¼ hr), 8·8% (1¾ hr), 12·9% (2 hr), 16·1% (2¼ hr), 29·8% (2½ hr), 59·5% (2¾ hr), 85·9% (3 hr), 38·4% (3¼ hr), 73·7% (3½ hr), 50% (4 hr), 96·4% (5 hr) and 100% (6 hr). Out of a total of 1006 eggs from non-ligated (control) Fallopian tubes, 95·5% were fertilized. Following ligation of one uterine horn 30 min, 1 hr or 2 hr after mating, 9·1, 38·7 and 55·2%, respectively, of the eggs were fertilized. It is concluded that although some spermatozoa may reach the tubo-uterine junction soon after mating, 2–5 hr are required before the number of spermatozoa entering the Fallopian tube is sufficiently high to produce maximum fertilization.

The gelatinous mass in rabbit semen.

RABBIT semen consists of two main parts, gelatinous and fluid. After ejaculation, the gelatinous part fills the lumen of the vagina as a copulation plug {bouchon vaginal). The existence of a copulation plug, which prevents the semen running out of the vagina after ejaculation, has been observed1 in a number of mammals besides rodents. Its importance in rats for fertile mating has been shown by Blandu2. That the production and maintenance of the gelatinous mass which mainly constitutes the copulation plug in the rabbit depends on testosterone has been shown by Parsons3. She found that castration in rabbits leads to complete absence of the gelatinous mass in ejaculates. When testosterone propionate was injected into such castrated rabbits, the gelatinous mass reappeared. She further found that implantation of stilbœstrol tablets into a buck previously castrated and implanted with testosterone brought about an inhibition of sex drive as well as a sharp decrease in seminal fructose, but an increase in the gelatinous part. This increase in the gelatinous part, however, remained unexplained.

家畜人工授精に於ける抗菌性諸物質の應用

The effect of several antibiotics on the spermlongivity of the rabbit semen which was preserved in room temperature was observed. Acetosulfamin, penicillin G, Streptomycin and Streptothricin group substances (No.36 substance, Seki-2, Seki-3, and Seki-7 substances) were used as the antibiotics.The semen-diluter was compenoated with the phosphate buffer solution to three groups of pH 7.6, 7.0 and 6.5 respectively. The antibiotics were contained in each these groups of preserved semen as follows. The density of Acetsulfamin was mede up 0.5mg×10-1, 0.5mg×10-2, 0.5mg ×10-3, 0.5mg×10-4, and 0.5mg×10-5 per ml of diluted semen, and those of the others were made up 1mg 10-1, 1mg×10-2, 1mg×10-3, 1mg ×10-1, and 1mg×10-5 per ml. As the control spermlongivity of the preserved semen was observed without carried on in sterilized condition, so there were no effect of bacteria.The average spermlongivities cf diluted semen without respect to the density of antibiotics were shown in the table.1) In the case of pH 7.6, the sperm lived longer in Penicillin G, streptomycin, Seki-3 substance and No. 36 substance in control. In Seki-2 substance, the lengivity was equal to control, 86 and in Acetsulfamin or SEKI-7 substance, it was shorter than in control. Particularly, SEKI-7 substance had a toxity for spermatozoa.2) In the case of pH 7.0, the longest spermlongivity was observed in SEKI-2 substance. In Acetsulfarmin, No. 36 substance and Streptomycin it was longer than in control, , In Penicillin G and Seki-7 substance, it was SRELATIVELY-3 shorter hanin control, and the shortest was in SEKI-3 tsubs- tance.3) In the case of pH 6.5, all the spermlongivity of the preserved semen containing these antibiotics were shorter than the control, and it was remarkably shorter in SEKI-3 and SEKI-7 substance.4) Feing compared one another those three kinds of pH the spermlongivity was considerably longer in pH 7.0 than in the cases of pH 7.6 and 6.5. The shortest was in pH 7.6.5) The antibiotics used, except SEKI-7 substance had no toxity for spermatozoa in the case of pH 7.0 and 7.6, and SEKI-3 substance showed, however, a little toxic effect on spermatozoa in the case of pH 7.0.Those results above mentioned suggest that six kinds of those antibiotics, namely Acetsulfamin, Penicillin G, Streptomycin, No. 36 substance, Seki -2 substance and Siki-3 substance may be able to applied to artificial insemination of domestic animals, if the condition of the medium is considered.Particularly, the application of Streptomycin, No. 36 substance and Seki-2 substance, of which actions in keeping the motility of spermatozoa suitably appear in the neutral or the basic, may give a satisfactory result

OBSERVATIONS ON THE MOTILITY OF RABBIT SPERMATOZOA IN DILUTE SUSPENSION

1. Rabbit spermatozoa suspended in Baker's solution rapidly lose motility at relatively high dilutions. At a concentration of 0.4 million per ml., the spermatozoa from most ejaculates are completely immotile within 2 or 3 hours. The same phenomenon occurs with chloride-free diluents and is therefore not due to the toxic action of chlorides. 2. This rapid immobilisation may be prevented by suspension in cell-free supernatants from other more concentrated suspensions of rabbit semen and by the accessory secretions from a vasectomised buck. The most effective supernatants are those prepared from suspensions of spermatozoa which have been left overnight before centrifuging. Immobilisation may also be prevented by many other agents, the most effective of which are gum arabic, starch, glycogen, and serum proteins (carbohydrate-containing or carbohydrate-free). Yet, in no case is the action of these substances as effective as more concentrated suspension in Baker's solution. 3. The immobilisation is not prevented by catalase, gelatin, agar, or sodium silicate. It is almost certainly not due to the toxic action of traces of heavy metals and is not affected by the use of water doubly distilled over glass in the preparation of the diluent, or by treating the diluent with activated charcoal. 4. Washing with Baker's solution does not cause immobilisation of spermatozoa suspended at 20 million per ml. at a stage at which the concentration of seminal plasma has been reduced to that equivalent to dilution to 0.4 million per ml. Further washing (six repeated centrifugings of 0.2 ml. semen in 4 ml. of Baker's solution) immobilises them. This confirms the opinion that loss of intracellular, or perhaps rather paracellular, material is a responsible agent in the dilution phenomenon.