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J. L. Brown, D. E. Wildt, J. R. Raath, V. de Vos, D. L. Janssen, S. B. Citino, J. G. Howard and M. Bush

Summary. Blood, testicular biopsies and electroejaculates were collected from adult male impala, free-ranging in the Kruger National Park (Republic of South Africa), during the breeding (rut; April–May) and nonbreeding (September–October) seasons. Blood samples were collected at 5-min intervals for 120 min from anaesthetized males (n = 7 impala/group) treated intravenously with saline, gonadotrophin-releasing hormone (GnRH: 1 μg/kg body weight) or human chorionic gonadotrophin (hCG: 10 or 30 iu/kg). Semen was collected from six more animals during the breeding season and 12 animals during the nonbreeding season using a standardized electroejaculation protocol. Ejaculates obtained during the nonbreeding season were of inferior quality to those collected during the breeding season, and were characterized by lower sperm concentrations, poorer sperm motility and more morphologically abnormal sperm forms. Within season, there were no differences in testosterone secretion between the two hCG doses, and these responses were similar to those observed after GnRH, but during the rut, testosterone secretion stimulated by both GnRH and hCG was approximately nine times greater than during the nonbreeding season. This seasonal increase in testosterone production was associated with a doubling in testicular volume and concentrations of luteinizing hormone (LH) receptors. Although concentrations of testicular follicle-stimulating hormone (FSH) receptors were similar between seasons, receptor content increased during rut as a result of increased testicular volume. In contrast to testosterone secretion, basal LH and FSH secretions were unaffected by season and GnRH-induced gonadotrophin secretion was reduced during rut. These data indicate that: (i) seminal quality in free-ranging impala undergoes seasonal changes coincident with alterations in testicular steroidogenic activity, and (ii) the increased testosterone secretion observed during rut is associated with increased testicular sensitivity to LH (via increased gonadotrophin receptors) rather than to increased circulating gonadotrophin concentrations or pituitary responsiveness to GnRH.

Keywords: impala; LH; FSH; testosterone; testis; receptors

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W. F. Swanson, J. G. Howard, T. L. Roth, J. L. Brown, T. Alvarado, M. Burton, D. Starnes and D. E. Wildt

Adult female ocelots (Felis pardalis) were treated with one of four dosages of equine chorionic gonadotrophin (eCG) and human chorionic gonadotrophin (hCG) (100 iu eCG/75 iu hCG, n = 3; 200 iu eCG/150 iu hCG, n = 4; 400 iu eCG/150 iu hCG, n = 5; 500 iu eCG/225 iu hCG, n = 5); hCG was administered 80 h after eCG. Ovaries of each animal were evaluated by laparoscopy 39–43 h after hCG, and blood was collected for progesterone and oestradiol analysis. With progressive increases in gonadotrophin dosage, female ocelots produced more (P < 0.05) unovulated follicles (≥2 mm in diameter), ranging from 1.3 ± 0.7 (mean ± sem) follicles per female at the lowest dosage to 8.8 ± 2.8 follicles per female at the highest dosage. Similarly, ocelots produced more (P < 0.05) corpora lutea with increasing gonadotrophin dosages, with mean values ranging from 0–5.0 ± 1.2 corpora lutea. However, across treatment groups, a similar proportion (P > 0.05) of females ovulated in response to each dosage. At laparoscopy, serum concentrations of oestradiol (overall mean, 330.2 ± 62.2 pg ml−1) and serum concentrations of progesterone (overall mean, 18.5 ± 6.4 ng ml−1) in ovulating females did not differ (P > 0.05) across treatment groups. Ten ovulating ocelots were laparoscopically inseminated with fresh (4.7 ± 0.2 × 106; n = 2 females) or frozen–thawed (10.7 ± 1.8 × 106; n = 8 females), motile spermatozoa. One female treated with 500 iu eCG/225 iu hCG and inseminated with 7.5 × 106 motile, frozen–thawed spermatozoa conceived and gave birth to a healthy male kitten after a gestation of 78 days. We conclude that ocelots are relatively insensitive to exogenous gonadotrophins, requiring much higher dosages (on a per body mass basis) to elicit an appropriate ovarian response than do any other felid species studied to date. Nonetheless, the gonadotrophin-treated female can become pregnant and carry offspring to term after laparoscopic intrauterine insemination with frozen–thawed spermatozoa.

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D. L. Cook, C. A. Smith, J. R. Parfet, R. S. Youngquist, E. M. Brown and H. A. Garverick

Summary. Non-lactating, multiparous dairy cows diagnosed as having cysts by palpation per rectum were used. Cysts were induced with oestradiol-17β (15 mg) and progesterone (37·5 mg) dissolved in ethanol and injected s.c. twice daily for 7 days. Following initial diagnosis of cysts, ovaries were exposed by midventral laparotomy, and the perimeter of the base of each cyst was marked with subepithelial injections of charcoal. Ovaries were removed from cows by transvaginal incision at 10 days (Group 1; N = 8), 20 days (Group 2; N = 8), or 40 days (Group 3; N = 7) after marking of cysts. Ovaries were examined for structures present and their relationship to the marked site. Corpora lutea with ovulation papilla were present in 7/23 cows (1/8, 4/8 and 2/7, for Groups 1, 2 and 3, respectively). In these 7 cows, corpora lutea were at a site different from the original structure that was marked. Marked structures persisted for the duration of the experimental period in 1 and 2 cows, in Groups 1 and 3, respectively. In the remaining 13 cows, new large follicular structures (cysts) were present at a site other than that marked with charcoal. These structures developed on the ovary contralateral to the one originally marked in 9 of 13 cows. Cysts are therefore dynamic in nature and may persist or may be replaced by others.

Keywords: ovary; follicular cysts; turnover rate; dairy cattle

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P J Williams, N Marten, V Wilson, J C Litten-Brown, A M Corson, L Clarke, M E Symonds and A Mostyn

Epidemiological studies suggest that low-birth weight infants show poor neonatal growth and increased susceptibility to metabolic syndrome, in particular, obesity and diabetes. Adipose tissue development is regulated by many genes, including members of the peroxisome proliferator-activated receptor (PPAR) and the fatty acid-binding protein (FABP) families. The aim of this study was to determine the influence of birth weight on key adipose and skeletal muscle tissue regulating genes. Piglets from 11 litters were ranked according to birth weight and 3 from each litter assigned to small, normal, or large-birth weight groups. Tissue samples were collected on day 7 or 14. Plasma metabolite concentrations and the expression of PPARG2, PPARA, FABP3, and FABP4 genes were determined in subcutaneous adipose tissue and skeletal muscle. Adipocyte number and area were determined histologically. Expression of FABP3 and 4 was significantly reduced in small and large, compared with normal, piglets in adipose tissue on day 7 and in skeletal muscle on day 14. On day 7, PPARA and PPARG2 were significantly reduced in adipose tissue from small and large piglets. Adipose tissue from small piglets contained more adipocytes than normal or large piglets. Birth weight had no effect on adipose tissue and skeletal muscle lipid content. Low-birth weight is associated with tissue-specific and time-dependent effects on lipid-regulating genes as well as morphological changes in adipose tissue. It remains to be seen whether these developmental changes alter an individual's susceptibility to metabolic syndrome.

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Linda Lefièvre, Kweku Bedu-Addo, Sarah J Conner, Gisela S M Machado-Oliveira, Yongjian Chen, Jackson C Kirkman-Brown, Masoud A Afnan, Stephen J Publicover, W Christopher L Ford and Christopher L R Barratt

Although sperm dysfunction is the single most common cause of infertility, we have poor methods of diagnosis and surprisingly no effective treatment (excluding assisted reproductive technology). In this review, we challenge the usefulness of a basic semen analysis and argue that a new paradigm is required immediately. We discuss the use of at-home screening to potentially improve the diagnosis of the male and to streamline the management of the sub-fertile couple. Additionally, we outline the recent progress in the field, for example, in proteomics, which will allow the development of new biomarkers of sperm function. This new knowledge will transform our understanding of the spermatozoon as a machine and is likely to lead to non-ART treatments for men with sperm dysfunction.