[Establishment of puberty in the doe rabbit (folliculogenesis and ovulation. Effect of rationing the diet].
We used 307 Californian doe-rabbits divided into 7 experimental groups. The first 4 groups, fed an ad libitum diet, were presented to the male at 11, 14, 17 or 20 weeks of age. The other 3 groups were fed a 75 p. 100 ad libitum diet and were presented to the male at 14, 17 and 20 weeks of age. Three to 5 does per group were killed at 8 postcoitum hours to check the ovarian follicles, and the remaining females, after effective mating, were killed 12 days later to check the ovulation rate. Acceptation of mating was homogeneous (75-80 p. 100) in all the groups, except in the one with the restricted diet presented to the male at 14 weeks of age (55 p. 100). In ad libitum-fed does, the percentage of females mated and ovulating reached one-third at 14 weeks and two-thirds at 17 and 20 weeks. Rationing retarded by 3 weeks live-weight gain and ability to ovulate. Whatever the diet given, the mean weight of does of this breed had to reach 3 kg before the first ovulation occurred and 3.3 kg before the percentage of females ovulating after mating became normal. The number of ova found in ovulating females did not differ statistically in any of the groups, but the rationed does tended to have fewer ova (- 8 p. 100) in direct relation to their live weight. In fact, whatever the diet, the number of ova increased more than 2-units for a weight increase of 1 kg of live weight. In ad-libitum-fed does, the follicle population doubled between 11 and 14 weeks, then decreased to attain at 20 weeks the value found at 11 weeks. Although this population was unimodal at 11 weeks, it became bimodal afterwards and was clearly so at 17-20 weeks. The second mode represented 5 then 8 p. 100 of the total follicles which were large-size (greater than 407000 mu2) and corresponded to preovulatory follicles. The number of atretic follicles followed a similar pattern. Rationing did not change the follicular population of the first mode; on the contrary, it altered the size and number of the large-sized follicle population of the second mode. Rationing also increased the percentage of atretic preovulatory follicles in the two oldest groups.
D000375:Aging; D000818:Animals; D004032:Diet; D005260:Female; D006197:Hair / Q000502:physiology; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation; D011817:Rabbits / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology; D012741:Sexual Maturation
L'établissement de la puberté chez la lapine (folliculogenèse et ovulation). Effet du rationnement alimentaire.