Selected sperm traits are simultaneously altered after scrotal heat stress and play specific roles in in vitro fertilization and embryonic development.

Improvements in the estimation of male fertility indicators require advances in laboratory tests for sperm assessment. The aims of the present work were (1) to apply a multivariate analysis to examine sperm set of alterations and interactions and (2) to evaluate the importance of sperm parameters on the outcome of standard IVF and embryonic development. Bulls (n = 3) were subjected to scrotal insulation, and ejaculates were collected before (preinsulation = Day 0) and through 56 days (Days 7, 14, 21, 28, 35, 42, 49, and 56) of the experimental period. Sperm head morphometry and chromatin variables were assessed by a computational image analysis, and IVF was performed. Scrotal heat stress induced alterations in all evaluated sperm head features, as well as cleavage and blastocyst rates. A principal component analysis revealed three main components (factors) that represented almost 89% of the cumulative variance. In addition, an association of factor scores with cleavage (factor 1) and blastocyst (factor 3) rates was observed. In conclusion, several sperm traits were simultaneously altered as a result of a thermal insult. These sperm traits likely play specific roles in IVF and embryonic development.

Cytogenetic analyses using C-banding and DAPI/CMA3 staining of four populations of the maize weevil Sitophiluszeamais Motschulsky, 1855 (Coleoptera, Curculionidae).

Cytogenetic data avalaible for the maize weevil Sitophiluszeamais Motschulsky, 1855 (Coleoptera: Curculionidae), one of the most destructive pests of stored cereal grains, are controversial. Earlier studies focused on single populations and emphasized chromosome number and sex determination system. In this paper, the karyotypes of four populations of Sitophiluszeamais were characterized by conventional staining, C-banding and sequential staining with the fluorochromes chromomycin-A3/4-6-diamidino-2-phenylindole (CMA3/DAPI). The analyses of metaphases obtained from the cerebral ganglia of last instar larvae and the testes of adults showed that the species had 2n = 22 chromosomes, with 10 autosomal pairs and a sex chromosome pair (XX in females and Xyp in males). Chromosome number, however, ranged from 2n = 22 to 26 due to the presence of 0-4 supernumerary chromosomes in individuals from the populations of Viçosa, Unai and Porto Alegre. With the exception of the Y chromosome, which was dot-like, all other chromosomes of this species were metacentric, including the supernumeraries. The heterochromatin was present in the centromeric regions of all autosomes and in the centromere of the X chromosome. The B chromosomes were partially or totally heterochromatic, and the Y chromosome was euchromatic. The heterochromatic regions were labeled with C-banding and DAPI, which showed that they were rich in AT base pairs.

Metabolic profile of serum and follicular fluid from postpartum dairy cows during summer and winter.

This study was designed to monitor the biochemical profiles of serum and follicular fluid (FF) of postpartum dairy cows during the summer (n=30) and winter (n=30). Blood and FF (follicles ≥ 9 mm) were obtained from Girolando cows at 30, 45, 60, 75 and 90 days postpartum. The samples were collected and analysed to determine glucose, total cholesterol (TC), triglyceride (TG), urea, sodium (Na), potassium (K) and calcium (Ca) levels. Throughout the study, the following clinical variables were measured: rectal temperature (RT), respiratory rate (RR) and body condition score (BCS). In addition, the temperature humidity index (THI) was calculated for each season. During the summer season, THI was higher, BCS decreased, there was an increase in RT, and glucose, urea, Na and K serum levels were decreased (P<0.05). The levels of TC, TG, urea, K and Ca in follicular fluid increased (P<0.05). Positive correlations (P<0.05) were observed between the serum and FF levels for glucose (r=0.29), TC (r=0.24) and Ca (r=0.30). Therefore, the biochemical profile of serum and FF of dairy cows under summer heat-stress conditions demonstrates marked changes that may impair fertility during lactation.

Distribution of the related weevil species Sitophilus oryzae and S. zeamais in Brazil.

The genus Sitophilus (Coleoptera: Curculionidae) encompasses species of great economic importance as stored grain pests worldwide. Among these species, the maize and the rice weevils (Sitophilus zeamais and Sitophilus oryzae, respectively) are particularly important in warmer climates. These two weevils exhibit closely morphological and ecological resemblance making difficult their proper identification and recognition of their distribution in grain-producing regions. Both species are recorded in South America and particularly in Brazil, but their respective distribution and prevalence were not yet assessed in the region. Therefore, several insect samples throughout Brazil were collected and subjected to morphological identification using male genitalia and also using molecular identification with species-specific primers designed for clear recognition of both the species. The primers were designed for the specific amplification of a gene fragment of the cytochrome oxidase subunit I, which exhibited high specificity during our preliminary experiments with insects from six populations of known species (either S. zeamais or S. oryzae). Both identification strategies provided the same results indicating prevalence of the maize weevil S. zeamais throughout the country. Two hypotheses may explain such prevalence: (i) the likely host preference of S. zeamais for maize because this is the most cultivated cereal in Brazil, and (ii) the prevalence of S. zeamais in tropical regions as compared with S. oryzae, which is more disseminated in subtropical and temperate regions.