Proportion Of Normal Spermatozoa Research Articles

Analysis of sperm quality in recombinant inbred mouse strains: correlation of sperm head shape with sperm abnormalities and with the incidence of supplementary spermatozoa in the perivitelline space.

Recombinant inbred strains were developed from reciprocal crosses between two inbred strains of mice (CBA and KE) differing in sperm head shape, proportion of normal sperm heads (CBA, 95%; KE, 78%) and fertilization efficiency (CBA, 100% of fertilized ova; KE, 72%), to determine whether the indices of sperm morphology and function were correlated. The following parameters were analysed in recombinant inbred and progenitor strains: index of sperm head shape (head width in the middle of its length/head length), percentage of abnormal sperm heads, percentage of spermatozoa with progressive movements, efficiency of penetration of hyaluronic acid polymer (Sperm Select) and percentage of fertilized ova after mating males from the tested strains with females from an outbred stock. For each investigated character, recombinant inbred strains, recombinant inbred EXCB and CBXE, could be divided into at least three categories: KE-like, CBA-like and intermediate, suggesting that in each case a minimum of two genes was involved. Recombinant strains derived from the reciprocal crosses of progenitor strains differed only with respect to the proportion of abnormal sperm heads, showing the involvement of the Y chromosome in determining this character. Penetration into Sperm Select was significantly correlated both with fertilization efficiency and sperm motility, while correlation with the proportion of normal spermatozoa did not reach the level of significance. However, there was a significant negative correlation of both sperm abnormalities and the incidence of supplementary spermatozoa in the perivitelline space with the index of sperm head shape.(ABSTRACT TRUNCATED AT 250 WORDS)

Concordance of mammalian ejaculate features

Different measures of ejaculate characteristics, such as ejaculate volume, proportion of normal sperm, proportion of motile sperm, and total number of sperm per ejaculate, are directly related to the probability of fertilization both when females copulate with a single male and particularly with multiple males. Selection will therefore favour the evolution of ejaculate characteristics which enhance the probability of fertilization, and I predict positive relations between ejaculate parameters. I used a literature survey of mammalian ejaculate parameters to test this prediction. The data set was corrected for similarity between taxa which resulted from common ancestry, and was reduced to statistically independent standardized linear contrasts. The number of sperm per ejaculate and ejaculate volume were positively related to body mass, but when the confounding effect of body mass was controlled for, all four ejaculate characteristics showed positive relations, and five out of six were statistically significant. This suggests that the different measures of ejaculate quality in mammals have been improved simultaneously, apparently by a common selective force.

Sperm count and sperm abnormality in male mice after exposure to 2.45 GHz microwave radiation

Adult male mice had the posterior halves of their bodies exposed at 44 W/kg a waveguide system to 2.45 GHz microwave radiation for 30 min. They were killed sequentially over 10 weeks and assessed for decreased sperm count and abnormal sperm morphology. The response in each assay was maximal 2–4 weeks after the exposure. This corresponds to microwaves having their greatest effect on spermatids and spermatocytes. Male fertility, assessed as the proportion of normal sperm per epididymis, was compared with results of an earlier study on dominant lethality. It is concluded that reduced male fertility correlates well with reduced pregnancy rate but less well with pre-implantation survival. Whilst microwaves clearly induced abnormally shaped sperm, those which achieved fertilization cannot have possessed a dominant mutation which would result in the post-implantation death of the embryo.

Use of low-dosage oral cyproterone acetate as a male contraceptive

To ascertain the effects of low-dosage cyproterone acetate (CPA) on the reproductive and endocrine functions of normal men, 25 volunteers were given CPA 0, 5 or 10 mg daily over 16 weeks, preceded by 12 weeks pretreatment observation and followed by 24 weeks posttreatment follow-up. CPA caused a decrease in sperm concentration, percentage motility, proportion of normal sperm and ability of the sperm to penetrate a column of cervical mucus in most patients. In addition, circulating testosterone, estradiol, LH and FSH levels were significantly reduced during treatment. All these changes reverted to the pretreatment level upon drug withdrawal. These findings suggest that firstly, although low dosage CPA was able to induce changes in seminal analyses, azoospermia was present in only one out of 15 subjects exposed to the drug. Secondly, the marked decrease in androgen levels associated with CPA treatment renders CPA unsuitable as a single entity agent for long-term male contraception.

Semen quality of Merino rams. 2. The effects of seasonal changes in day length on semen quality

Two groups of five medium Wool Peppin Merino rams were individually penned in an animal house for 18 months. During this time the normal seasonal pattern of changes in day length was reversed for one group of rams (treatment). The control group of rams received normal daylight at Trangie (32�S). From late September 1960, semen was collected once every 14 days from all rams by electro-ejaculation and semen quality was assessed. Significant treatment X months of year interactions found for most semen characteristics. The semen of treated rams had a lower pH during October 1960, and a higher proportion of normal sperm and number of sperm per ejaculate during November 1960, than the semen of control rams. During the period February to June 1961 the semen of treated rams was of a lower quality than the semen of control rams. During November- December 1961 and January to March 1963, the semen of treated rams had a significantly lower proportion of live sperm (P<0.005) than the semen of control rams. From these results it was not possible to determine if the daily photoperiod exerted a direct or indirect effect on the semen quality of Merino rams.