Jesús Ricardo Aké-López

Perfiles sanguíneos de progesterona y estradiol del Pecari tajacu en cautiverio

The objective was to characterize the levels of progesterone (P4) and 17b estradiol (E-17b) in blood of 11 Pecari tajacu adult females in captivity. The females were in the presence of males but separated by a wire mesh. Blood samples were taken every 6 days during 3 months. The estimation of the levels of the steroid hormones was carried out by radioimmunoassay in solid phase. Hormonal profiles were plotted against time, to determine the duration of each ovarian cycle and the number of cycles. Nine animals showed estrous cycle and 2 did not. The average duration of the ovarian cycle was 26.8±4.8 days. The average concentration of P4 in the luteal phase was 22.95±4.94 ng/mL, and during the follicular phase was 1.2±0.73 ng/mL (p<0.05). The levels of E-17b in the luteal phase were 6.89±2.79 pg/mL, and 32.17±7.29 pg/mL in the follicular phase (p<0.05). The presence of the ovarian cycles was variable, although the duration was within the range of values established for this species under captivity. The synchrony of the hormonal profiles of P4 and E-17b during the ovarian cycle was inverted.

Effect of season on follicular population, quality and nuclear maturation of bovine oocytes under tropical conditions

The aim was to determine the effect of season of the year and the presence of a corpus luteum (CL) on follicular population (FP) and the quality of the oocytes, and of season on nuclear maturation of the bovine oocytes under tropical conditions. Three seasons were evaluated: hot-dry (March-June), hot-humid (July-October) and fresh-humid (November-February). In a first study, 1112 bovine ovaries were obtained from a local slaughterhouse. Follicles were classified as small (≤4mm), middle (4.1-8mm) and large (≥8.1mm); and the maximum diameter of the follicle (MDF) and CL (MDCL) were also recorded. The oocytes were collected by aspiration and classified as viable (grade I and II) and damaged (grade III and IV). In the second study, 2261 viable oocytes were matured in vitro, and then fixed and stained with Lacmoid to classify the stage of development as mature (metaphase II), immature or degenerate. Data were analyzed using analysis of variance and chi-square procedures. The largest FP of large follicles (0.67), MDF (1.18mm), MDCL (1.87mm), and the highest proportion of viable oocytes (34.19%) were obtained during the hot-humid season (P<0.05). The ovaries without CL had the greatest FP (10.34) with more viable oocytes (24.44%). The highest proportion of mature oocytes (76.92%) was also obtained in the hot-humid season. In conclusion, season influenced FP, MDF, MDCL, and the quality and nuclear maturation of oocytes. The presence of a CL in the ovary resulted in a decrease of FP and viability of oocytes.