Effects of Dietary Zinc Supplementation on Spermatic Characteristics of Rabbit Breeders

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 age. The treatments were respectively, 0, 50, 100, 150 and 200 ppm supplemental zinc in the diet. The animal began receiving ZnO in their diets as soon as they were weaned. First semen collection was performed at 28 wks of age, being collected six times weekly per animal. The volume of each ejaculate was registered and an aliquot was separated for further analyses. Due to a possible error in saline formol concentration, it couldn't be possible to estimate spermatozoa concentration through microscopic counting. The alternative used to bypass this problem was to determine the volume of cell mass (volume of spermatozoa) of every ejaculate. The technique consisted in using Wintrobe tubes (graded tubes with subdivisions of 0.01 ml) to centrifuge semen samples, at 4,000 rpm for 20 minutes, and measure the cellular volume each sample. Mean values of total ejaculate didn't differ (p > 0.05) among treatments. Animal fed 50, 100 and 150 ppm ZnO presented higher spermatozoa volume as compared to the other groups.