J.B. Barreto Filho

Características andrológicas e do sêmen de touros do composto Red Norte (Nelore x Tabapuã x Red Angus x Sinepol)

Reproductive traits of cross-breed Red Norte (Nelore x Tabapua x Red Angus x Sinepol) young bulls averaging of 13.9±0.8 month-old were evaluated, in order to determine the puberty onset and semen quality in these animals. Scrotal circumference (SC), body weight (BW), and semen parameters of 70 bulls were measured. Animals were allotted in three groups (G) according to their SC: GI=27-33cm (n=24), GII=33-35cm (n=24), and GIII=35-43cm (n=22). BW and age of each group were, respectively: GI=411.2±37.4kg and 13.8±1.0 month-old, GII=426.9±31.5kg and 14.0±0.7 month-old, and GIII=438.4±38.3kg and 14.0±0.6 month-old. Seminal physical characteristics for same order of groups were: volume 4.2±3.1mL, 5.3±2.6mL, and 4.5±2.1mL; motility 31.3±24.1%, 44.2±23.9%, and 43.9±21.5%; and vigor 2.8±1.6, 3.5±1.3, and 3.5±1.3. The spermiogram presented concentration values of 130.5±266.2x106/mL, 289.5±390.2x106/mL, and 333.9±523.7x106/mL; total defects of 81.4±15.9%, 73.8±15.4%, and 67.9±19.0%; major defects of 87.3±26.2%, 66.8±24.9% and 56.7±17.1%; and minor defects of 16.6±14.9%, 33.2±24.9%, and 43.3±17.1%, for same order of groups. Seven out of 70 bulls were considered satisfactory potential breeders. Results showed that semen pathology progressively decreased when SC increased.

Evolução do peso testicular de cordeiros da raça Santa Inês alimentados com diferentes níveis de energia

The development of the testicule weight of Santa Ines lambs, fed different energy levels, was evaluated. Sixty-four lambs were distributed in four treatments: A - 8.7%; B - 17.3%; C - 26.0% and D - 34.7% of neutral detergent fiber (NDF) supplied by the diet forage, determining the variation of the metabolizable energy intake. Four animals from each treatment were slaughtered at pre-defined ages of 43 days, 83 days, 123 days and 173 days. After slaughtering, the testicles were separated from the epididimous and individually weighted. The animals fed diets A and B presented higher metabolizable energy intake (14.11Mcal/LW0.75), higher live weight (18.89kg and 17.09kg, respectively) and higher testicules weight (62.54g and 27.16g, respectively), indicating that the testicular development is highly dependent on the body development and the quantity of metabolizable energy intake. The prediction of the testicules weight by the scrotal circumference showed to be more efficient than the age or the live weight of the animals.

Secreção de interferon-tau em embriões bovinos produzidos in vitro frescos e congelados

The effect of cryopreservation in IFN-tau, from bovine embryos produced in vitro was evaluated. Two treated groups (G1= fresh bovine embryos, n=59 and G2= freezed embryos, n=84) were used to study the effect of cryopreservation on IFN-tau secretion. After reaching the blastocyst phase, the embryos were kept on individual culture for additional period of 7 days. On days 3 and 7 after the beginning of embryos cultivation, samples of the media culture were taken for IFN-tau secretion titration. Oocysts taken from follicles ranging from 3 to 5mm in diameter were obtained from ovaries of females at slaughterhouse. The embryos were frozen, after being dehydrated with ethylene glycol (1.8m), conditioned on 0.5ml palletes and frozen. Frozen embryos secreted lower IFN-tau than fresh embryos (P<0.05). At day 7 it was registered higher IFN-tau secretion from trophoblast than at day 3 (P<0.05). The increasing of IFN-tau secretion was observed when the blastocyst began to longed and it was directly related to the embryos development. The synthesis of IFN-tau is related to the capability of development of the blastocyst. Cryopreservation is a method that affects the maternal recognition of pregnancy and the post-freezing embryo development.

Antiviral activity of bovine uterus and placenta induced by Newcastle disease virus

Investigou-se a atividade antiviral do utero e da placenta bovina, ao longo da gestacao, induzidos pelo virus da doenca de Newcastle (NDV). Explantes do endometrio e carunculas foram colhidos do utero. Os tecidos corioamniotico, corioalantoide e cotiledones foram dissecados da placenta fetal. Os cultivos celulares foram induzidos com aproximadamente 6,0 unidades hemaglutinantes do NDV. Os sobrenadantes foram concentrados 20 vezes, filtrados em dispositivos com superficie de separacao de 100kDa e a atividade antiviral foi titulada em celulas MDBK e virus da estomatite vesicular (VSV). Endometrio, carunculas e cotiledones nao apresentaram atividade antiviral. Corioamniotico e corioalantoide produziram fatores antivirais ao longo da gestacao. Estes fatores nao foram relacionados aos IFN - a, g ou t e nem ao TNF - a. O padrao de producao de fatores antivirais acompanhou o desenvolvimento dos tecidos fetais e titulos mais altos foram observados no final da gestacao. Estes dados sugerem que os genes de IFNs induzidos por virus localizam-se nas membranas fetais da placenta e a expressao desses genes e dependente do estadio da gestacao.

N-terminal amino acids of bovine alpha interferons are relevant for the neutralization of their antiviral activity

The structure-function relationship of interferons (IFNs) has been studied by epitope mapping. Epitopes of bovine IFNs, however, are practically unknown, despite their importance in virus infections and in the maternal recognition of pregnancy. It has been shown that recombinant bovine (rBo)IFN-alphaC and rBoIFN-alpha1 differ only in 12 amino acids and that the F12 monoclonal antibody (mAb) binds to a linear sequence of residues 10 to 34. We show here that the antiviral activities of these two IFNs were neutralized by the F12 mAb to different extents using two tests. In residual activity tests the antiviral activity dropped by more than 99% with rBoIFN-alphaC and by 84% with rBoIFN-alpha1. In checkerboard antibody titrations, the F12 mAb titer was 12,000 with rBoIFN-alphaC and only 600 with rBoIFN-alpha1. Since these IFNs differ in their amino acid sequence at positions 11, 16 and 19 of the amino terminus, only these amino acids could account for the different neutralization titers, and they should participate in antibody binding. According to the three-dimensional structure described for human and murine IFNs, these amino acids are located in the alpha helix A; amino acids 16 and 19 of the bovine IFNs would be expected to be exposed and could bind to the antibody directly. The amino acid at position 11 forms a hydrogen bond in human IFNs-alpha and it is possible that, in bovine IFNs-alpha, the F12 mAb, binding near position 11, would disturb this hydrogen bond, resulting in the difference in the extent of neutralization observed.