The outcome of sperm competition in species with alternative male reproductive strategies may be determined by fair or loaded raffle mechanisms. The sperm production and quality of male Atlantic salmon using alternative reproductive tactics were investigated in order to determine the relative importance of sperm quality for male reproductive success. Sexually mature resident parr males produced greater numbers of spermatozoa per millilitre of ejaculate and invested more in their gonads as a percentage of body mass than their anadromous counterparts. Parr males had greater proportions of motile spermatozoa and a greater sperm ATP content as compared with anadromous males. Parr males invested relatively more in sperm quality and sperm numbers after the effect of body size was accounted for. In fertilization experiments, parr males fertilized greater proportions of eggs than anadromous males. A polynomial model exhibited a trade-off between testes mass and ejaculate expenditure and explained 60% of the variation. These results establish that, in sperm competition with dominant males, parr males may compensate for behavioural subordinance by producing physiologically superior spermatozoa.

Male salmon exhibit alternative mating strategies, as both older anadromous adults and precocious juveniles (parr) participate in the spawning of a single female. This study tested the following hypotheses: 1) different intensities of sperm competition may reflect different sperm tail optima; 2) long spermatozoa are superior to short ones, with an associated cost on sperm longevity; and 3) a disfavored role in sperm competition selects for parr investing more in sperm quality. Comparisons included sperm morphological traits, whereas sperm quality was investigated by motility duration observations, measurement of the sperm adenylate system, and fertilization experiments. No evidence of different adaptive sperm dimensions between the male types was found. Positive association between spermatocrit and energy charge was, however, detected. Sperm length parameters correlated positively with ATP, energy charge, and fertilization success, whereas no evidence for an effect of sperm morphology on longevity was found. Male parr had greater spermatocrit than adults and fertilized equal proportions of eggs as adults despite a pronounced numerical subordinance in the fertilization experiments. It is concluded that a long sperm tail and midpiece may be selected to optimize energetic demands under conditions of increased sperm competition intensity.

No abstract

The effect of water temperature on the duration of sperm motility, the time lapse after activation by fresh water and the fertility of eggs was studied in Atlantic salmon and brown trout. Eggs of both species were fully fertile in fresh water after 512 s. No interspecific differences were noted in egg fertility at the lower water temperatures, but the brown trout eggs showed a higher resistance to high temperatures, indicating a better physiological thermotolerance. A highly significant effect of temperature on the overall duration of sperm motility was found, with a marked peak at 3-4 C for salmon and a weaker one for trout. After freshwater activation the eggs of both species remained fertile for a longer time than the sperm were mobile.1997 The Fisheries Society of the British Isles

Background: Obstetric labor and childbirth are mostly regarded as a physiological process, whereas social, cultural, psychological and transcendental aspects have received less attention. Labor support has been suggested to promote labor progress. The aim of this study was to investigate whether continuous labor support by a midwife promotes labor progress and vaginal delivery.Material and Methods: A randomized controlled study at a university hospital in Sweden in 2015–17. Primiparous women with singleton pregnancy and spontaneous labor onset were randomized to continuous support (n = 30) or standard care (n = 29) during delivery. The primary outcome was the duration of active labor. Secondary outcomes were delivery mode, women's need of labor analgesia and satisfaction with delivery, maternal cortisol levels, and neonatal morbidity.Results: Continuous support was followed by shorter active labor 11.0 ± 5.7 h compared to 13.7 ± 3.9 h with standard care (p = 0.001). Women in the continuous support group tended to have lower cortisol levels and low cortisol during the first (p = 0.02) and second (p = 0.04) stages of labor were correlated with shorter active labor. Continuous support was followed by spontaneous delivery in 73%, instrumental delivery in 24% and emergency cesarean section in 3% in contrast to standard care which was followed by spontaneous delivery in 62%, instrumental delivery in 24% and cesarean in 14% (p = 0.19). The continuous support group received combined analgesic methods more often (p = 0.04). Women's satisfaction with delivery and neonatal morbidity were comparable.Conclusion: Continuous labor support was followed by shorter active labor compared to standard care. Women with continuous support had a high rate of vaginal delivery and tended to have lower cortisol levels during all stages of active labor reflecting a lower stress level. Low cortisol was correlated to shorter active labor. Based on these results, we recommend continuous labor support for all primiparous women during active labor.

No abstract

Treatment with prostaglandin(PG)-E 2 is clinically efficient for cervical priming. The aim of this study was to evaluate the impact of PG-E 2 on the expression of the progesterone (PR), androgen (AR) and glucocorticoid (GR) receptors in human uterine cervix in prolonged pregnancy.The study groups were postterm nulliparous women with unripe cervices undergoing cervical priming with PG-E 2 before labor induction. Responders (n = 12) who delivered vaginally were compared with non-responders (n = 10), who underwent cesarean section due to failure to progress to the active phase of labor. Controls (n = 18) with vaginal partus at a normal gestational age served as a reference group. Cervical levels of PR-A and PR-B isoforms, AR and GR, serum levels of their ligands and sex hormone-binding globulin (SHBG) were quantified.The responder group displayed lower total PR-AB and AR protein levels as compared to nonresponders, and lower PR-B and AR protein levels as compared to controls. In addition, the PR mRNA level was lower in responders as compared to non-responders. The GR protein level did not differ between the groups.We conclude that successful PG-E 2 priming was followed by a progesterone and androgen withdrawal at the receptor level in the uterine cervix.

Oral PG in solution was less effective than vaginal PG gel in achieving VB <24 h. However, oral PG was safer, since it resulted in fewer CSs without increasing maternal morbidity or neonatal asphyxia.