Development of One vs Multiple Ovulatory Follicles and Associated Systemic Hormone Concentrations in Mares     

OJ Ginther  JC Jacob  MO Gastal  EL Gastal  MA Beg 《Reproduction in domestic animals》2009,44(3):441-449

Ablation of follicles ≥  6 mm in diameter and treatment with PGF2α 10 days after ovulation were used to induce the development of ovulatory waves. Comparisons were made between induced waves with one (33 waves, 72%) and multiple (13 waves, 28%) ovulatory follicles. Diameter deviation was defined as the separation of follicles into dominant and subordinate categories. Multiple ovulatory follicles were preceded by more (p < 0.001) follicles ≥ 20 mm at the beginning of deviation, higher LH preceding deviation (approached significance, p < 0.08), lower (p < 0.05) concentrations of FSH on the day of deviation and thereafter, and higher (p < 0.0003) oestradiol by 2 days after deviation. During the peri-ovulatory period, systemic hormone concentrations for waves with multiple ovulations involved higher oestradiol before ovulation (approached significance, p < 0.07), lower FSH (p < 0.04) before and after ovulation, and both higher progesterone (p < 0.05) and lower LH (p < 0.05) beginning the day after ovulation. Results indicated that by the beginning of deviation there were more follicles ≥  20 mm and subsequently greater oestradiol production in waves that led to the development of multiple ovulatory follicles, and during the peri-ovulatory period differences between one and multiple ovulations were consistent with the negative effects of the ovarian hormones on the gonadotropins.  相似文献   

Protected areas and native freshwater bivalves are not in the same place in south-east Brazil     

Igor Christo Miyahira  Maria Cristina Dreher Mansur  Luiz Eduardo Macedo de Lacerda  Isabela Cristina Brito Gonçalves  Glauco Gil Sant'Anna  Sonia Barbosa dos Santos 《水产资源保护:海洋与淡水生态系统》2023,33(1):102-114

1. Bivalves are important components of freshwater ecosystems; however, they are also one of the most threatened animal groups, especially members of the order Unionida. The main threats to freshwater bivalves are habitat modification and invasive species. Protected areas are a common way to minimize impacts and preserve native species, but they are rarely designated with a focus on freshwater invertebrates.
2. The main goal of this article was to describe the distribution of freshwater bivalves in the state of Rio de Janeiro, and the relationship between these species and bioclimatic areas, land use and protected areas.
3. Five native and two invasive bivalve species have been reported in Rio de Janeiro. They occur mainly in bioclimatic areas related to the Paraíba do Sul River and Campista Lowlands. The few records of bivalves inside protected areas are in areas of sustainable use that offer a lower level of protection, and frequently in sympatry with invasive bivalves.
4. Thus, the established protected areas in Rio de Janeiro are not adequately effective for freshwater bivalve conservation, and some species remain under threat even within them. Freshwater bivalves thus remain largely unprotected in the state.
5. The development of new protected areas and management plans should consider other faunal groups that are usually ignored, such as freshwater bivalves, to achieve more inclusive and effective protection.

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