Influences of food quality and quantity on the male reproductive organs of a seasonally breeding rodent, the pouched mouse (Saccostomus campestris), from a seasonal but unpredictable environment

Reproduction in the pouched mouse (Saccostomus campestris) is inhibited in winter in the field and this seasonality is not controlled by photoperiod alone. The present study examines the hypothesis that reproduction in the pouched mouse is opportunistic (sensu Bronson 1989) and that the winter inhibition of reproduction is controlled by a reduction in either food quantity or quality. Food restriction (70 % of normal daily food intake) for six weeks, under short day conditions, was associated with a significant decrease in body fat index and mass of the accessory glands, testes and epididymides, while a high-fibre diet resulted in a significant reduction in fat index and masses of both the accessory glands and epididymides. A lowfibre/ low-protein diet had no significant effect on either fat index or masses of the  reproductive organs. Although the three experimental diets resulted in assimilation of significantly less energy than the controls, they did not inhibit  spermatogenesis.We conclude that reproduction in the pouched mouse in the Eastern Cape Province is probably opportunistic and that the winter inhibition of reproduction may be controlled by a reduction in available energy which results from a combination of the lower ambient temperatures of winter and reduced food quantity and/or quality.Key words: reproduction, energetics, Africa, Mammalia

Use of a zona laser treatment system in assisted hatching: Optimal laser utilization parameters

Objective: This study aimed to establish the benefit of laser micromanipulation of the zona pellucida as a method of assisted hatching and to determine the optimal technical settings. Design: Prospective pilot study. Setting: University teaching hospital. Animal(s): Six- to 8-week-old F1 female mice. Intervention(s): Mouse embryos were treated with a laser (Hamilton Thorne Research) using both research and preset clinical settings. The research option allows the user to alter pulse duration, number of pulses, and beam intensity. In this study, laser intensity and duration, as well as the depth and number of disruptions, were altered. Main Outcome Measure(s): Embryos were scored after treatment as either arrested blastocysts, arrested during hatching, hatched, or degenerate. Result(s): The treatment where the laser intensity was halved but the number of laser pulses used was doubled was the most beneficial treatment. Zona thinning was not effective. Conclusion(s): The study showed that laser-assisted hatching can safely and significantly increase the percentage of embryos reaching the hatched blastocyst stage. A proportionately sized hole in a human embryo may have the same beneficial effect as has been shown in this study. ©2005 by American Society for Reproductive Medicine.Articl