Caracterização de proteínas do plasma seminal e sua relação com parâmetros de qualidade do sêmen criopreservado em ovinos / Characterization of seminal plasma proteins and its relationship with quality parameters of frozen semen in ram

Os objetivos deste trabalho foram analisar o perfil proteico do plasma seminal ovino e identificar proteínas relacionadas com a congelabilidade do sêmen que possam ser utilizadas como marcadores para essa característica. Foram utilizados os ejaculados de cinco reprodutores, nos quais foram realizadas avaliações espermáticas e dos quais os plasmas seminais obtidos por centrifugação foram submetidos à eletroforese bidimensional em gel de poliacrilamida. Foram identificados 92 spots, considerando todos os animais analisados. A avaliação dos dados obtidos evidenciou variações significativas nos resultados das análises do sêmen dos animais e uma variabilidade no perfil proteico no plasma seminal dos carneiros. As proteínas 03 (7,9kDa; pI 6,35), 23 (13,6kDa; pI 5,01) e 31 (21,4kDa; pI 4,75) se destacaram, por apresentarem maior expressão e relações com as características espermáticas. Sugere-se que mais estudos sejam realizados para verificar se as proteínas 03, 23 e 31 podem ser utilizadas como marcadores da capacidade criopreservadora do sêmen.

The objective of this study was to analyze the protein profile of ram seminal plasma and to identify proteins associated with semen freezability, which could be used as marker for predicting this feature. Semen from five rams was used. The sperm analysis was held and the seminal plasma obtained by centrifugation was submitted to two-dimensional electrophoresis using acrylamide gel. Ninety two spots were identified considering the analyzed animals. The results showed a significant variation among sperm analysis of the animals and variability in the protein profile of the seminal plasma of the rams. The proteins 03 (7.9kDa; pI 6.35), 23 (13.6kDa; pI 5.01) e 31 (21.4kDa; pI 4.75) stood out because they showed higher expression and because of its relationship with the sperm characteristics. It is suggested more studies to verify if proteins 03, 23 and 31 could be used as markers of semen freezability.

Association of the estrogen receptor gene Pvu II restriction polymorphism with expected progeny differences for reproductive and performance traits in swine herds in Brazil

Estrogen has an important function in swine reproduction and growth. A Pvu II restriction enzyme polymorphism has been proven to be an important genetic variation in the estrogen receptor gene (ESR) and may be considered as a candidate gene for use in pig production but there is no data regarding the prevalence of this polymorphism in the Brazilian pig population. We used DNA samples from the following three purebred pig breeds: Large White (336 females and 26 males), Landrace (304 females and 27 males) and Pietrain (125 females and 11 males). The ESR genotyping was performed using PCR-RFLP. For each breed, genotypes for the ESR gene were compared independently for expected progeny differences (EPD) in litter size (LS), average daily weight gain (DWG) (g/day) and back fat thickness (BT) as measured in mm by ultrasound. In the Large White breed, but not the other breeds, the ESR genotype was significantly (p < 0.05) associated to LS, DWG and BT. Large Whites genotyped as AA or AB had higher EPD values for the LS and BT traits compared to BB Large Whites, while AA Large Whites had higher DWG EPD values than BB Large Whites. Our results for the Large White population showed that the A allele has a beneficial effect on LS, DWG and BT expected progeny differences.

Association of a PIT1 gene polymorphism with growth hormone mRNA levels in pig pituitary glands

Fourty-six non-castrated, halothane-free, male Landrace pigs were genotyped by PCR-RFLP for the Rsa I polymorphism in the PIT1 gene and classified into AA and AB genotypes. Total RNA was extracted from the pituitaries and the relative quantities of growth hormone (GH) mRNA were determined by semi-quantitative RT-PCR. Pigs with the AB genotype had higher levels of GH mRNA than those with the AA genotype (p = 0.034; Kruskal-Wallis test). This result suggests that the Rsa I polymorphism may be involved in Pit-1 protein expression or function, which in turn may influence GH transcription and expression. Thus, the Rsa I PIT1 gene polymorphism in this pig line may be used as a molecular marker to identify higher GH expression and possibly select for carcass and performance traits affected by GH.

Protocol for extraction of genomic DNA from swine solid tissues

Molecular diagnostics are performed by using DNA from different body tissues. However, it is necessary to obtain genomic DNA of good quality. Due to the impossibility of collecting blood from slaughtered animals, DNA extraction from solid tissues is necessary. The objective of this study was to describe a protocol of DNA extraction from swine skin, adipose, brain, liver, kidney and muscle tissues. We obtained high molecular weight DNA of good quality, shown by agarose gel and amplification of two DNA fragments, 605bp and 891pb, by PCR. Spectrophotometric analysis of DNA concentration showed variation among the DNA from different tissues, with the liver and adipose tissues presenting the greatest and the smallest concentration, respectively. The described protocol has proven to be advantageous due to its simplicity, quickness, affordable reagents and absence of phenol, resulting in a high molecular weight DNA of good quality from several tissues