Is the Function of the Porcine Sperm Reservoir Restricted to the Ovulatory Period?

The uterotubal junction (UTJ) and caudal isthmus are recognized as a functional pre-ovulatory sperm reservoir (SR). Spermatozoa are released from the SR in a complex and concerted action. However, whether this functionality is restricted only to the ovulatory period is still open to debate. Our study was aimed to analyze the presence of spermatozoa within the UTJ (SR), isthmus (ISTH) and ampulla (AMP) after laparoscopic intrauterine insemination (LIUI) either in the peri- (PERI) or post-ovulatory (POST) period or at mid cycle (MID). Each uterine horn of estrus synchronized gilts (n=12) was inseminated with 20 ml sperm (29.5×10⁶ cells/ml). Oviducts were recovered 7 h after LIUI and separated into the UTJ, ISTH and AMP, and sections were flushed with 10 ml PBS+EDTA solution. After centrifugation, the sperm pellet was evaluated by Čeřovský staining. The median sperm numbers in the PERI, POST and MID groups were 578, 171 and 789 in the UTJ; 545, 233 and 713 in the ISTH; and 496, 280 and 926 in the AMP, respectively, and there were differences between the POST and MID groups (P<0.05) but not between the oviductal sections of each group (P>0.05). Compared with the MID group, the percent of intact sperm cells was higher (P<0.01) in the PERI and POST groups (32.8 vs. 66.4 and 76.8%). Also, the percentages of aberrations in the acrosome and tail were higher (P<0.05) in the MID group. Based on this, it can be assumed that the sperm reservoir is active during different phases of the estrus cycle. However, the mid-cycle oviduct environment considerably impairs sperm cell quality.     

Preliminary Report on the “Humane Coyote-Getter” for the Control of the Black-Backed Jackal thos Mesomelas in the Transvaal

The diet of Canis mesomelas was studied in the central Namib Desert, South West Africa. A sample of 772 scats was collected from three main sites (coastal, dry riverine and open plains) and two minor sites (Diamond Area 2). Scats from the coastal site contained predominantly bird material whereas scats from the riverine and plains sites contained predominantly plant material. The present study is compared with other feeding studies of this species, particularly in South Africa.     

Does the Microbial Flora in the Ejaculate Affect the Freezeability of Stallion Sperm?

In an attempt to evaluate the possible relationship between the microbial flora in the stallion ejaculate and its ability to freeze, three ejaculates from five stallions were frozen using a standard protocol. Before freezing, an aliquot was removed for bacteriological analysis. Bacterial growth was observed in all the ejaculates studied. The isolated microorganisms were: Staphylococcus spp. and Micrococcus spp. (in all the stallions), β-haemolytic Streptococcus (in stallions 3 and 4), Corynebacterium spp. (in stallions 1, 3–5), Rhodococcus spp. (in stallion number 2), Pseudomonas spp. (in stallion number 1) and Klebsiella spp. (in stallions 1, 3 and 5). The presence and richness of Klebsiella and β-haemolytic Streptococcus in the ejaculate were related to two sperm variables post-thaw, namely the proportion of dead spermatozoa (ethidium+ cells; r = 0.55, p < 0.05) and the amplitude of lateral displacement of the sperm head (ALH, μm; r = −0.56, p < 0.05), respectively. The degree of growth of Corynebacterium spp. in the ejaculate was positively correlated with the percentage of spermatozoa showing high caspase activity post-thaw (r = 0.62, p < 0.05). The presence and number of colonies of β-haemolytic Streptococcus were negatively correlated (r = −0.55, p < 0.05) with low sperm caspase activity. It is concluded that the microbial flora of the equine ejaculate may be responsible for some of the sublethal damage experimented by the spermatozoa during cryopreservation.     

The microstructure of the cuticle‐less shell of the eggs of the domestic hen

1. Open pores were a notable feature of the shell of hens' eggs which were naturally devoid of cuticle.

2. In contrast with normal eggs, the surface of the cuticle‐less shell was irregularly contoured and, in many instances, deeply fissured.     

Is Semen Analysis Useful to Predict the Odds that the Sperm will Meet the Egg?

Any mammalian spermatozoon that achieves successful in vivo fertilization has to perform almost perfectly in many disparate functions and overcome a series of obstacles imposed by the female reproductive tract. This implies that during formation in the testis and epididymis, the spermatozoa did not incur any morphological, metabolic, immunological or genetic abnormalities. Given that the spermatozoa are such highly differentiated cells, this means that every cellular compartment must not only be intact but must also respond appropriately to intracellular and extracellular signals. Assuming that a spermatozoon possesses this level of perfection, and is able to reach and penetrate an oocyte, it can only be regarded as 'fertile' if the DNA it carries is intact and able to sustain embryonic development. Although the proportion of inseminated spermatozoa that meet these criteria is vanishingly small, the female reproductive tract applies stringent selection criteria during sperm transport and, as a result, the probability of conception around the time of ovulation is very high. If laboratory tests of semen quality could approach the efficacy of the female reproductive tract, it would be possible to predict the odds of spermatozoa meeting the egg; however, this is not possible at present. In this article, I suggest a simple model to illustrate how a battery of laboratory tests could eventually be used to make these predictions.