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Synchronization of estrus and ovulation are of paramount importance in modern livestock improvement programs. These methods are critical for assisted reproduction technologies, including artificial insemination and embryo transfer, that can increase productivity. In the current study, subcutaneous implants containing norgestomet were placed for long (14 days), medium (9 days), and short (5 days) periods of time in 70 crossbred ewes undergoing fixed-time artificial insemination. The resulting effects on estrus synchronization and conception rates were subsequently evaluated. Among the synchronized ewes, 85.7% (60/70) underwent estrus over a period of 72 h after progestagen treatment ceased. The shortest mean interval between withdrawal of the device and onset of estrus (34.2 ± 8.9 h) was observed in the G14 days of P4 group (p < 0.05). The conception rate of the G14 days of P4 group was statistically higher than that of the other groups (83.3% vs. 60.9% vs. 47.8%; p < 0.05). In conclusion, 14 days of norgestomet treatment produced higher conception rates and a greater number of pregnancies at the beginning of the breeding season.

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These data suggest that RAGE is involved in the development of obesity and insulin resistance.

The effect of different concentrations of alpha lipoic acid (ALA) on the development and morphology of preantral follicles, as well as the proliferative activity of granulosa cells, was assessed after short-term culture. Ovaries (n = 5) of five seasonal anestrous mares were harvested in a local abattoir. At the laboratory, nine ovarian fragments (5 × 5 × 1 mm) from each animal were used. One fragment was immediately fixed in Bouin and subjected to histological and immunohistochemistry (proliferating cell nuclear antigen, PCNA) analyses (noncultured group; D0 = day 0). The other eight fragments were cultured in situ for two (D2) or six (D6) days in MEM or MEM plus ALA (50, 100, or 250 μM). After culture, fragments were subjected to histology and PCNA analyses. After two days of culture, ALA 50 and ALA 100 had the greatest (P < 0.05) percentage of normal primordial follicles (97.2 and 95.1%, respectively), when compared to other groups, and did not differ (P > 0.05) from the fresh noncultured control group. Furthermore, the total percentage of normal follicles was greater (P < 0.05) in the ALA 50 and ALA 100 than in the MEM-D2 group. After six days of culture, the highest (P < 0.05) proliferative activity of granulosa cells in developing follicles was observed for the groups MEM (92.9%), ALA 50 (100%), and ALA 100 (96.4%). In conclusion, the results of this study demonstrated that (1) ALA 50 and ALA 100 preserved the morphological integrity of equine primordial follicles for up two days of culture, and (2) granulosa cells of developing follicles enclosed in ovarian tissue and cultured for up to six days in MEM with or without ALA were highly stained by PCNA.

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ResumoO objetivo deste estudo foi comparar dois protocolos pré-aspiração folicular associados com PGF2α. Foram utilizadas 14 novilhas da raça Nelore, não gestantes, com escore corporal de 2,5 (escala de 1 a 5). Todos os animais foram submetidos aos dois tratamentos (cross over) para controle da onda de crescimento folicular, um através da ablação de todos os folículos 3 dias antes da aspiração folicular (PAF) e outro por controle hormonal (PCH) com benzoato de estradiol e progesterona injetável. Os dados foram analisados pelo ANOVA e as diferenças significativas pelo teste de Tukey, com nível de significância de 5 %. O protocolo controle hormonal (PCH) mostrou-se vantajoso por propiciar maior média de folículos e oócitos, além de redução no número de corpos lúteos evitando também o procedimento extra de aspiração prévia para ablação dos folículos. Conclui-se que o protocolo hormonal (PCH) apresentado mostra-se uma alternativa viável para tratamentos pré-aspiração, havendo benefícios adicionais pela ausência de corpo lúteo no momento da aspiração folicular. Palavras-chave: Aspiração folicular, bovinos, protocolo pré-aspiração folicular AbstractThe aim of this study was to evaluate two pre-aspiration protocols associated with PGF2α . Nelore heifers (n=14), not pregnant, body score of 2.5 (scale of 1 to 5) were used. All animals were submitted to two treatments (cross over) to control the follicular wave of growth, one by follicular ablation 3 days before the aspiration (PAF) and another by hormonal control with estrogen and injectable progesterone (PCH). Data were analyzed by ANOVA and significant differences were compared by Tukey test, with significance level of 5%. The hormonal control protocol (PCH) provided advantages as higher average of follicles and oocytes, reduction in the number of corpus luteum and one procedure less -the follicle ablation. We concluded that the hormone control protocol (PCH) is a viable alternative for preaspiration treatments, with additional benefits for the absence of corpus luteum at the time of follicular aspiration.

This study investigated the effects of different concentrations of FSH (10, 50, 100 and 200 ng/ml) in supplemented MEM+ on the development of equine pre-antral follicles that were cultured in vitro for 2 or 6 days. The ovaries (n = 5) from mares in seasonal anoestrus were collected from a local abattoir. Ten ovarian tissue fragments of approximately 3 × 3 × 1 mm were obtained from each animal. The fragments were cultured in situ for 2 days (D2) or 6 days (D6) in MEM+ or MEM+ supplemented with FSH at four different concentrations, establishing the following 11 groups: control (D0); MEM + (D2); MEM + (D6); MEM + 10 ng/ml of FSH (D2); MEM + 10 ng/ml of FSH (D6); MEM + 50 ng/ml of FSH (D2); MEM + 50 ng/ml of FSH (D6); MEM + 100 ng/ml of FSH (D2); MEM + 100 ng/ml of FSH (D6); MEM + 200 ng/ml of FSH (D2); and MEM + 200 ng/ml of FSH (D6). Follicles were observed in only 9.65% (388 of 4,018) of the histological sections. Of the 861 follicles evaluated, 488 were in the primordial stage, and 373 were in various developmental stages; 59.7% were morphologically normal. Regarding the integrity of the pre-antral follicles, the groups with 100 ng/ml FSH of 2-days culture as well as 50, 100 and 200 ng/ml FSH of 6-days culture provided the best results. In conclusion, the in vitro culture of abattoir-derived equine ovarian fragments presented better morphological integrity when supplemented with FSH for 6 days, in comparison with the MEM culture group. However, no clear effects were observed with FSH regarding the promotion of activation from a primordial to a developing follicle.