Large-scale SNP discovery and construction of a high-density genetic map of Colossoma macropomum through genotyping-by-sequencing.

Colossoma macropomum, or tambaqui, is the largest native Characiform species found in the Amazon and Orinoco river basins, yet few resources for genetic studies and the genetic improvement of tambaqui exist. In this study, we identified a large number of single-nucleotide polymorphisms (SNPs) for tambaqui and constructed a high-resolution genetic linkage map from a full-sib family of 124 individuals and their parents using the genotyping by sequencing method. In all, 68,584 SNPs were initially identified using minimum minor allele frequency (MAF) of 5%. Filtering parameters were used to select high-quality markers for linkage analysis. We selected 7,734 SNPs for linkage mapping, resulting in 27 linkage groups with a minimum logarithm of odds (LOD) of 8 and maximum recombination fraction of 0.35. The final genetic map contains 7,192 successfully mapped markers that span a total of 2,811 cM, with an average marker interval of 0.39 cM. Comparative genomic analysis between tambaqui and zebrafish revealed variable levels of genomic conservation across the 27 linkage groups which allowed for functional SNP annotations. The large-scale SNP discovery obtained here, allowed us to build a high-density linkage map in tambaqui, which will be useful to enhance genetic studies that can be applied in breeding programs.

Frequency of species of Eimeria in females of the Holstein-Friesian breed at the post-weaning stage during autumn and winter.

The frequency of species of the genus Eimeria in a dairy herd in the municipality of Boa Esperança, Southern region of the State of Minas Gerais was assessed. From 37 females of the Friesian breed aged three to seven months, 259 feces samples were analyzed between May and September 2008. The examinations to quantify oocysts per gram of feces (OPG) and identify Eimeria species were conducted at the Veterinary Parasitology Laboratory of the Federal University of Lavras. Eleven species of Eimeria were identified, namely: E. bovis (23.2%), E. zuernii (22.6%), E. ellipsoidalis (20.3%), E. cylindrica (14.1%), E. subspherica (5.4%), E. canadensis (3.5%), E. alabamensis (2.4%), E. auburnensis (2.4%), E. pellita (2.1%), E. brasiliensis (2%) and E. bukidnonensis (1.9%). E. bovis, E. zuernii and E. ellipsoidalis were the most frequent and the ones with the highest oocyst shedding over time (p < 0.05). Differences in OPG counts were found between most months studied (p < 0.05). The large number of Eimeria species found, in particular E. bovis and E. zuernii, indicates that Eimeria sp. has significant pathogenic potential in dairy cattle in the South of Minas Gerais.

Frequency of species of Eimeria in females of the holstein-friesian breed at the post-weaning stage during autumn and winter / Frequência das espécies de Eimeria em fêmeas da raça holandesa na fase de recria durante o outono-inverno

The frequency of species of the genus Eimeria in a dairy herd in the municipality of Boa Esperança, Southern region of the State of Minas Gerais was assessed. From 37 females of the Friesian breed aged three to seven months, 259 feces samples were analyzed between May and September 2008. The examinations to quantify oocysts per gram of feces (OPG) and identify Eimeria species were conducted at the Veterinary Parasitology Laboratory of the Federal University of Lavras. Eleven species of Eimeria were identified, namely: E. bovis (23.2 percent), E. zuernii (22.6 percent), E. ellipsoidalis (20.3 percent), E. cylindrica (14.1 percent), E. subspherica (5.4 percent), E. canadensis (3.5 percent), E. alabamensis (2.4 percent), E. auburnensis (2.4 percent), E. pellita (2.1 percent), E. brasiliensis (2 percent) and E. bukidnonensis (1.9 percent). E. bovis, E. zuernii and E. ellipsoidalis were the most frequent and the ones with the highest oocyst shedding over time (p < 0.05). Differences in OPG counts were found between most months studied (p < 0.05). The large number of Eimeria species found, in particular E. bovis and E. zuernii, indicates that Eimeria sp. has significant pathogenic potential in dairy cattle in the South of Minas Gerais.

Avaliou-se a frequência das espécies do gênero Eimeria em um rebanho leiteiro, criado no município de Boa Esperança, região Sul do Estado de Minas Gerais. Foram analisadas 259 amostras de fezes de 37 fêmeas bovinas, da raça holandesa, com faixa etária compreendida entre três e sete meses, no período de maio a setembro de 2008. O exame para quantificar oocisto por grama de fezes (OPG) e identificação das espécies de Eimeria foi realizado no Laboratório de Parasitologia Veterinária da UFLA. Foram identificadas onze espécies de Eimeria, sendo elas: E. bovis (23,2 por cento), E. zuernii (22,6 por cento), E. ellipsoidalis (20,3 por cento), E. cylindrica (14,1 por cento), E. subspherica (5,4 por cento), E. canadensis (3,5 por cento), E. alabamensis (2,4 por cento), E. auburnensis (2,4 por cento), E. pellita (2,1 por cento), E. brasiliensis (2 por cento) e E. bukidnonensis, sendo E. bovis, E. zuernii e E. ellipsoidalis as mais frequentes e aquelas com maior número de oocistos eliminados ao longo do tempo (p < 0,05). Diferenças na contagem de OPG foram encontradas na maioria dos meses avaliados (p < 0,05). A grande quantidade de espécies de Eimeria encontradas, em especial E. bovis e E. zuernii, indicam um importante potencial patogênico da Eimeria sp. em gado leiteiro no Sul de Minas Gerais.