10 research outputs found

    Genomic Population Structure of the Main Historical Genetic Lines of Spanish Merino Sheep

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    According to historiographical documentation, the Romans first began to select Merino sheep in the Iberian Peninsula during the first century, with the aim of obtaining a breed appreciated for the quality of its wool. This process continued locally during the Middle Ages, when Spanish sheep were protected, and their export to foreign countries was banned. It was during the 16th century when individual Merino sheep were allowed to spread around the world to be used to improve the wool quality of local breeds. However, the wool crisis of the 1960s shifted the selection criteria of the Merino breed towards meat production at the expenses of wool. Consequently, individuals that display the genetic and phenotypic characteristics of those sheep originally bred in the kingdom of Spain in the Middle Ages are extremely difficult to find in commercial herds. In this study, we characterized the genetic basis of 403 individuals from the main historical Spanish Merino genetic lines (Granda, Hidalgo, Lopez-Montenegro, Maeso, Donoso and Egea), which were bred in isolation over the last 200 years, using a genomic approach based on genotyping data from the Axiom™ Ovine 50 K SNP Genotyping Array. Our analysis included measuring population structure, genomic differentiation indexes, runs of homozygosity (ROH) patterns, and an analysis of molecular variance (AMOVA). The results showed large genetic differences between the historical lines, even though they belong to the same breed. In addition, ROH analysis showed differences due to increased inbreeding among the ancient generations compared with the modern Merino lines, confirming the breed’s ancestral and closed origin. However, our results also showed a high variability and richness within the Spanish historical Merino lines from a genetic viewpoint. This fact, together with their great ability to produce high-quality wool, suggests that ancestral Merino lines from Spain should be considered a valuable genetic population to be maintained as a resource for the improvement of wool-producing sheep breeds all around the world

    Efecto del destete sobre el perfil de ácidos grasos de corderos de raza merina

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    Con la finalidad de estudiar el efecto de la prolongación del aporte de leche materna a los corderos de la raza Merina Española sobre las características de la grasa intramuscular y subcutánea, se han empleado 16 corderos machos de raza Merina Española distribuidos en dos lotes: corderos no destetados y que han permanecido con la madre hasta el día de su sacrificio y corderos destetados con 12 kg de peso vivo y que desde ese momento han ingerido únicamente alimento concentrado. El perfil lipídico de la grasa intramuscular y subcutánea se determinó por cromatografía gaseosa. Los corderos que fueron destetados con 12 kg de peso vivo y que fueron alimentados con alimento concentrado hasta el día de su sacrificio presentaron mejor conformación que los corderos que fueron alimentados con leche materna y alimento concentrado hasta el día de su sacrificio. Los corderos que recibieron leche materna hasta el día de su sacrificio presentaron mayor contenido de ácidos grasos deseables para la salud humana (9cis-11trans CLA y serie n-3)

    Carcass and meat quality in light lambs in the segureña breed

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    Meat and carcass quality were studied in 124 Segureña breed lambs, 62 males and 62 females, slaughtered at the market weight, of 19-25 kg. Carcasses, with a yield between 48 percent (CCW/SW) and 55 percent (HCW/EW), were qualified for the most part in the 2 class of conformation as a fairly fatty, of 2/3 covered kidney and pink color muscle. There were differences among sexes for the fatness scores. The pelvic limb represents the 33.6 percent of the carcass, the shoulder 19.5 percent, the ribs+loin 17.7 percent, the breast 11.1 percent, the neck 7.3 percent, and the anterior ribs 6.7 percent; for commercial categories 58.1 percent pertained to the first category, 19.5 percent to the second and 19.8 percent to the third. Carcass were formed by 19.9 percent of fat, 52.7 percent muscle and 19.2 percent bone; these values show an ideal degree of fatness, in the local market. The sex had a significant effect on the percentage of fat and bone of the carcass. The average pH values, 6.6 and 6.5, following the preparation of the carcass for m. longissimus dorsi and m. triceps, decreased to 5.8 and 5.9, respectively, at 24 hours post mortem. These muscles presented a water holding capacity of 16.4 and 9.9 percent, and a tenderness of 3866 and 3945 g/cm2. The haem pigments and the color of m. longissimus dorsi and m. rectus abdominis confirm the results of its subjective evaluation.Se estudiaron características de calidad de la canal y de la carne en 124 corderos, 62 machos y 62 hembras, de raza Segureña sacrificados a peso de mercado, 19-25 kg. Las canales, con rendimientos entre el 48 p.100 (PCF/PVS) y el 55 p.100 (PCC/PVV), son de conformación normal (nota 2), medianamente grasas, de riñón cubierto 2/3 y músculo de color rosa; registrándose diferencias entre sexos para las calificaciones de engrasamiento. Al despiece, la pierna representó el 33,6 p.100 de la canal, la espalda el 19,5 p.100, el costillar el 17,7 p.100, los bajos el 11,1 p.100, el cuello el 7,3 p.100 y el badal el 6,7 p.100; lo que por categorías comerciales supone el 58,1 p.100 para las de 1ª, el 19,5 p.100 y 19,8 p.100 para las de 2ª y 3ª, respectivamente. La canal contenía 19,9 p.100 de grasa, 52,7 p.100 de músculo y 19,2 p.100 de hueso lo que muestra su buen grado de acabado. El sexo afectó significativamente al porcentaje de grasa y hueso de la canal. Los valores iniciales de pH, 6,6 y 6,3 para m. longissimus dorsi y m. triceps brachii, descienden a 5,8 y 5,9 a las 24 horas post mortem, respectivamente. La capacidad de retención de agua de estos músculos fue de 16,4 y 9,9 p.100 y su dureza media 3866 y 3945 g/cm2. El pigmento hemínico y el color de m. longissimus dorsi y m. rectus abdominis confirman la valoración subjetiva del color de la carne

    Características de carcaça de cordeiros Texel x Bergamácia, Texel x Santa Inês e Santa Inês puros, terminados em confinamento, com casca de café como parte da dieta Carcass characteristics of Texel x Bergamacia, Texel x Santa Inês and pure Santa Inês lambs, finished in confinement with coffee hull as a part of the diet

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    RESUMO - Trinta e seis cordeiros (18 machos inteiros e 18 fêmeas) de três diferentes grupos genéticos: 12 cordeiros cruzas Texel x Bergamácia (T x B), 12 cordeiros cruzas Texel x Santa Inês (T x S) e 12 cordeiros puros Santa Inês (SI) foram alimentados com três diferentes dietas experimentais: A- sem casca de café; B. com casca de café in natura; e C- com casca de café, tratada com uréia e grão de soja moído. Os pesos das carcaças quente e fria, o rendimento de carcaça quente (RC), a quebra de peso da carcaça devido ao resfriamento, as medidas de comprimento interno e total da carcaça, o comprimento de perna, o comprimento total de perna (CTP), o perímetro da garupa (PG), a largura da garupa (LG), a profundidade do tórax (PT) e a gordura subcutânea (GS), de acordo com a dieta, o grupo genético e sexo foram avaliados. Não houve efeito das dietas sobre as variáveis avaliadas. Os cordeiros cruzas T x B e T x S apresentaram menor CTP e maiores PG, LG e GS. Os cordeiros T x B apresentaram valores superiores para PT. Houve superioridade dos animais cruzados nos pesos das carcaças quente e fria, não ocorrendo diferenças para o rendimento da carcaça quente entre os grupos genéticos. Não houve diferença entre machos e fêmeas para GS. As fêmeas apresentaram melhor RC que os machos. Para as outras características, os machos mostraram valores superiores em relação às fêmeas.<br>ABSTRACT - Thirty six lambs (18 male and 18 female) from three different genetic groups: 12 lambs Texel x Bergamacia, (T B), 12 lambs Texel x Santa Inês (T S) and 12 lambs pure Santa Inês (SI) were fed with three different experimental diets: A - without coffee hulls; B - with in natura coffee hull and; C - with coffee hull, treated with urea and whole ground soybean seed. The hot carcass weight (CQ), cold carcass weight (CF), hot carcass dressing (RC), cooling weight loss (QR) and the measures of internal length (CI), and total (CE), leg length (CP), total leg length (CTP), croup circumference (PG), croup width (LG), thoracic depth (PT) and subcutaneous fat width (GS), according to the diet, the genetic group and sex were evaluated. Diets did not affect any of the analyzed variables. The crossbred T x B and T x S lambs showed lower CTP and higher PG, LG, and GS. The Tx B lambs showed higher values for PT. There were higher hot and cold carcass weights for the crossbred lambs, and there was no difference for hot carcass dressing among the genetic groups. There was no difference between male and female lambs for GS. The female lambs showed better RC than male lambs. The male lambs showed higher values for all the other characteristics in relation to the female lambs

    The value of the continuous genotyping of multi-drug resistant tuberculosis over 20 years in Spain

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    Molecular epidemiology of circulating clinical isolates is crucial to improve prevention strategies. The Spanish Working Group on multidrug resistant tuberculosis (MDR-TB) is a network that monitors the MDR-TB isolates in Spain since 1998. The aim of this study was to present the study of the MDR-TB and extensively drug-resistant tuberculosis (XDR-TB) patterns in Spain using the different recommended genotyping methods over time by a national coordinated system. Based on the proposed genotyping methods in the European Union until 2018, the preservation of one method, MIRU-VNTR, applied to selected clustered strains permitted to maintain our study open for 20 years. The distribution of demographic, clinical and epidemiological characteristics of clustered and non-clustered cases of MDR/XDR tuberculosis with proportion differences as assessed by Pearson’s chi-squared or Fisher’s exact test was compared. The differences in the quantitative variables using the Student's-t test and the Mann–Whitney U test were evaluated. The results obtained showed a total of 48.4% of the cases grouped in 77 clusters. Younger age groups, having a known TB case contact (10.2% vs 4.7%) and XDR-TB (16.5% vs 1.8%) were significantly associated with clustering. The largest cluster corresponded to a Mycobacterium bovis strain mainly spread during the nineties. A total of 68.4% of the clusters detected were distributed among the different Spanish regions and six clusters involving 104 cases were grouped in 17 and 18 years. Comparison of the genotypes obtained with those European genotypes included in The European Surveillance System (TESSy) showed that 87 cases had become part of 20 European clusters. The continuity of MDR strain genotyping in time has offered a widespread picture of the situation that allows better management of this public health problem. It also shows the advantage of maintaining one genotyping method over time, which allowed the comparison between ancient, present and future samples
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