Osvaldo José da Silveira Neto

Assessment of primers designed for the subspecies-specific discrimination among Babesia canis canis, Babesia canis vogeli and Babesia canis rossi by PCR assay

Canine babesiosis is an infectious disease caused by either Babesia gibsoni or Babesia canis protozoans. The latter is also classified under three different phylogenetic groups, referred to as subspecies B. canis canis, B. canis vogeli and B. canis rossi. The objective of the present study was to validate and standardize a PCR assay to discriminate the organisms at the subspecies level. First, the reference sequences of the 18S rRNA, 5.8S rRNA and 28S rRNA genes, including the internal transcribed spacer 1 (ITS1) and 2 (ITS2) of the most common species and subspecies of the genus Babesia were retrieved from the GenBank database. Subspecies-specific primers (BAB3, BAB4 and BAB5) and one genus-specific primer were designed from the alignment of the sequences. The PCR assays were evaluated in three different combinations of primer pairs in order to assure complete specificity for each reaction. The results of the tests had demonstrated effectiveness of the novel primer pairs BAB1/BAB3, BAB1/BAB4 and BAB1/BAB5 for the amplification of the subspecies-specific target fragments of 746 bp (B. c. canis), 546 bp (B. c. vogeli) and 342 bp (B. c. rossi) by PCR. The original enzymatic amplification assays with novel primers reported in this paper were confirmed to be a reliable tool for the specific discrimination among B. canis subspecies by single-step PCR assays.

Differences in the susceptibility of two breeds of dogs, English cocker spaniel and beagle, to Rhipicephalus sanguineus (Acari: Ixodidae)

The objective of this study was to evaluate differences in susceptibility to Rhipicephalus sanguineus (Latreille) of two breeds of dogs: English cocker spaniel and beagle. Three artificial infestations of ticks using a capsule on the back of the dogs were carried out at 15 day intervals. Six dogs of each breed were infested with 100 larvae, 50 nymphs and 20 adults (10 males and 10 females). Every 2 days, the ticks on the dogs were evaluated and the engorged ones counted and collected. The ticks were stored in climatic chambers and inspected every two days for 14 days. The following parameters were recorded: number of engorged ticks, engorgement period, percentage of ecdysis, female weight, conversion of body weight to eggs and larval hatchability. In the ticks recovered from the cocker spaniel, higher percentages of ecdysis of larvae and nymphs, greater number of adults attached and engorged and higher reproductive performance of the females (conversion to eggs and hatchability) were observed. The period of engorgement, number of engorged nymphs and weight of the females did not differ much by breed, but more larvae were attached and engorged in the beagle. In the two breeds, an effect of the successive infestations on the number of engorged larvae and nymphs was observed, which demonstrates the development of a response to the infestation in these stages. However, the percentage of ecdysis and the conversion to eggs was affected only in the more resistant beagles. Based on what was presented, it can be concluded that the animals of the race English cocker spaniel are more susceptible to R. sanguineus than the beagles and that the infestations affect the development of the tick, especially in resistant individuals.

Design of primer pairs for species-specific diagnosis of Leishmania (Leishmania) infantum chagasi using PCR

The objective of this study was to design and evaluate new primers for species-specific detection of L. infantum chagasi using PCR. Two combinations of primer pairs were established with the aim of obtaining specific amplification products from the L. infantum chagasi 18S rRNA gene. The combinations of the primer pairs and the respective sizes of the PCR products, based on the U422465 GenBank reference sequence of L. infantum chagasi, were: LCS1/LCS3 (259 bp) and LCS2/LCS3 (820 bp). It was concluded that the new PCR assays optimized using the primer pairs LCS1/LCS3 and LCS2/LCS3 were effective for specific detection of L. infantum chagasi, with analytical sensitivity to detect 1 pg/µL of DNA.

Susceptibility of Rhipicephalus (Boophilus) microplus to acaricides in dairy cattle in the region of Goiano West, Brazil

The Rhipicephalus (Boophilus) microplus is the main cattle tick, responsible for large losses in Brazilian cattle. Control of R. (B.) microplus relies almost exclusively on the use of chemicals. But increasingly this species of tick has shown resistance to products used mainly by the poor use of acaricides. The goal of this work is to evaluate the situation of the resistance of the cattle tick Rhipicephalus (B.) microplus to acaricides used in the Western Goiano, as well as analyze the factors involved in this resistance. Tests will be performed immersion Riphicephalus ticks (Boophilus) microplus using ten commercial products with different active ingredients, in order to verify the effectiveness rate of products available acaricides. After the test results, it was found that the product was more effective Cypermethrin 6.0 g + 50 g Chlorpyrifos 98.20% and was less effective Deltrametrina 25 g with 19.87%, since the majority of active ingredients did not show good efficacy on the tick population in the region Goiano West.

Avaliação de parâmetros fisiológicos em búfalas da raça Murrah

The aim was to evaluate the rectal, body superficial temperature and respiratory frequency in Murrah breed buffalos. The study was conducted in farm located in Pires do Rio city, Goiás state. It was evaluated 07 buffalos of Murrah breed. The average superficial temperature measured at 13:00, 14:00 e 15:00 hours was 32.35±0.48, 33.20±0.47 e 32.45±0.44 o C, respectively. The average rectal temperature at 13:00, 14:00 e 15:00 hours was 38.25±0.19, 39.05±0.22 e 38.48±0.24 o C, respectively. The respiratory frequency at 13:00, 14:00 e 15:00 hours was 22.85±4.45, 27.42±4.86 e 22.28±3.14 rpm. The evaluation of physiological parameters does not show that the animals reached the thermic stress during the evaluation.

Avaliação de carcaça de bovinos da raça Tabapuã com ultrassonografia

Measures ultrasound enable the knowledge level of muscularity, the thickness of subcutaneous fat of the animal and the degree of marbling of the meat by measuring in vivo animal. The objective of this study was to evaluate carcass traits of 20 animals Tabapuã, quantifying the mean values and standard deviations of carcass traits and estimate simple correlations between body weight and ultrasound measurements. Carcass characteristics were measured by ultrasound ribeye area (AOL), fat thickness (EGS), obtained between the 12th and 13th rib, marbling score (MAR), ratio: height x width of the counterfilet (RATIO), AOL/100 and EGS/100. The estimates for body weight, AOL, AOL/100, RATIO, MAR, EGS and EGS/100 averages: 472.23 ± 140.80, 75.78 ± 21.17, 16.33 ± 2.63, 0 45 ± 0.04, 1.03 ± 0.19, 2.33 ± 0.77, 0.52 ± 0.11, respectively. The value of AOL found indicates animals with high yield of meat cuts.

Comparação de desempenho de bovinos Nelore e mestiços Nelore-Rubia Gallega em sistema de confinamento

Objetivou-se comparar o desempenho de ganho em peso medio diario, o rendimento de carcaca, a conversao alimentar e a eficiencia biologica de novilhos da raca Nelore e dos mesticos Nelore-Rubia Gallega mantidos em confinamento. Foram utilizados 273 bovinos inteiros, sendo 138 da raca Nelore e 135 mesticos, com media de 22 meses de idade. As analises estatisticas foram realizadas pelo programa estatistico SAS, e as medias do peso inicial, ganho medio diario e peso final foram comparadas pelo teste t (p<0,01). O rendimento de carcaca foi determinado em relacao ao peso de corpo vazio da carcaca quente e o peso vivo de saida. A conversao alimentar foi calculada atraves dos Kg de MS consumidos/Kg de ganho. A eficiencia biologica foi medida atraves dos Kg de MS consumidos/arroba de carcaca produzida. A media do peso inicial, peso final e ganho medio diario dos animais da raca Nelore foram superiores (p<0,01) em relacao aos animais mesticos Nelore-Rubia Gallega. Os mesticos Rubia Gallega apresentaram rendimento 1,22% superior aos animais de raca Nelore. Quanto a conversao alimentar os mesticos consumiram 1,39 Kg de MS a menos para cada Kg de ganho em peso. Em relacao a EB Para cada arroba produzida os animais Nelores tiveram que consumir 37,09 Kg de MS a mais do que os mesticos Nelore-Rubia Gallega. A utilizacao de animais com genetica Rubia Gallega em cruzamentos com zebuinos apresentam melhor rendimento de carcaca, conversao alimentar e eficiencia biologica.

Simulação de dados para avaliação econômica do sistema de cria de bovinos de corte em pastagem de Brachiaria brizantha cv. Marandu

Objetivou-se proceder a simulacoes de dados de producao de bovinos de corte, na fase de cria, por meio de um rebanho base composto por 500 femeas da raca Nelore, acima de 36 meses submetidas a IATF, e 20 touro de repasse. Foram simuladas 5 situacoes diferentes: S1: 60%; S2: 70%; S3: 80%; S4: 85% e S5: 90% de natalidade. Indices de natalidade de 60 ate 80% com descarte de 50% de femeas vazias, a margem liquida fica negativa, ficando positiva apenas com indices acima de 80%.