Human spermatids from ejaculate and testicular tissue have been utilized for evaluating human fertilization by intracytoplasmic sperm injection (ICSI) and, where possible, compared with spermatozoa utilizing sibling oocytes. Round and elongated spermatids obtained from ejaculates were either prepared through Percoll gradients or isolated and washed individually using subzonal insemination needl...

KONDRACKI, S., M. IWANINA and A. WYSOKINSKA, 2015. Assessment of the relationship between physical ejaculate parameters and the sexual activity of Landrace boars. Bulg. J. Agric. Sci., 21: 882–888 The study involved 11 Landrace boars, aged 8-9 months and used for insemination purposes. Each boar was assessed four times for its sexual activity: at the beginning of breeding service and after 3, 6...

Several reports demonstrating the presence of messenger RNAs for sperm-specific nucleoproteins, the protamines PRM-1, PRM-2, and the transition protein TP-1 as well as beta-actin, c-MYC, HLA1, and beta 1 integrin have challenged the accepted view of the transcriptional dormance of terminally differentiated spermatozoa. Whatever nuclear activity the ejaculate spermatozoon may possess, these data...

Aim: Present investigation was carried out to study the physical characteristics of Kankrej bulls semen by evaluation of various semen parameters from neat semen and at various stages of semen preservation. Materials and Methods: A total of 60 ejaculates, 10 each from 6 mature Kankrej bulls, once in a week for 10 weeks, were collected and analyzed for various semen attributes. Result: The mean ...

The coyote is a seasonally breeding mammal, with most copulations occurring between December and April (depending on location). The objective of this study was to characterize seasonal changes in serum testosterone concentrations, testicular volume, and ejaculate quantity and quality in captive male coyotes. There were seasonal differences in testicular volume, with the greatest volume (20.2+/-...

Semen production data from an Austrian AI centre collected between 2000 and 2004 were analysed. In total, 12,746 ejaculates from 301 AI bulls were examined considering different effects on ejaculate volume, sperm concentration, percentage of viable spermatozoa in the ejaculate, total spermatozoa per ejaculate and motility. The model included the fixed effects of age of bull, collection interval...

Conventional belief holds that an immune response to ejaculate antigens should interfere with fertilisation and establishment of pregnancy. However, emerging evidence now supports the opposing view-that insemination acts to activate maternal immune mechanisms exerting a positive effect on reproductive events. In a response well documented in rodents, semen triggers an influx of antigen-presenti...

Theory predicts that mate choice can lead to an increase in female fecundity if the secondary sexual traits used by females to assess male quality covary with the number of sperm transferred during copulation. Where females mate multiply, such a relationship between male attractiveness and ejaculate size may, additionally (or alternatively), serve to augment the effect of indirect selection by ...

While sperm competition has been extensively studied, the mechanisms involved are typically not well understood. Nevertheless, awareness of sperm competition mechanisms is currently recognised as being of fundamental importance for an understanding of many behavioural strategies. In the yellow dung fly, a model system for studies of sperm competition, second male sperm precedence appears to res...

In order to study the effects of dietary zinc supplementation on spermatic characteristics, 27 New Zealand White rabbits were used, following a completely randomized design with five treatments (Zn levels). Two treatments had had six replicates, while the rest had five. The rabbits were selected immediately after weaning (4 weeks of age) and used in the experiment that extended till 34 weeks of...