The performance of a genome scan for serum lipid traits at 45 and 190 d in 5 half-sib families of Duroc pigs allowed us to detect several pig chromosomal regions with significant effects on these phenotypes. In the current work, we aimed to refine the position of 1 chromosome 4 (SSC4) genome-wide significant QTL for serum triglyceride concentration at 190 d. Genotyping of 4 additional microsatellites allowed reduction of the 90% confidence interval of this QTL to the genomic interval between markers SW2409 and SW839. Sequencing experiments were performed to characterize the variability of 2 lipid-related genes, the lipoprotein receptor-related protein 12 (LRP12) and tribbles homolog 1 (TRIB1) loci, that map to this region. In this way, 2 (c.771A > G and c.1101A > G) and 1 (c.*156_157del) polymorphisms were identified at the LRP12 coding region and TRIB1 3′ untranslated region, respectively. Association analyses between LRP12 and TRIB1 genotypes did not reveal any significant effect on serum lipid concentrations, suggesting that variation of these two loci does not explain the segregation of the SSC4 QTL. However, highly significant associations were observed for gluteus medius saturated fatty acid content (LRP12 c.1101A > G, P = 0.0006; TRIB1 c.*156_157del, P = 0.0003). In the light of these and other findings, the potential involvement of LRP12 and TRIB1 in muscle lipid metabolism deserves to be further explored. Copyright © 2013. American Society of Animal Science .

Objective: The goal of this study was to characterize and investigate the effect of single nucleotide polymorphisms (SNPs) or InDels in tyrosinase related protein 1 (TYRP1), dopachrome tautomerase (DCT), and Ras-related protein 38 (RAB38) genes on coat color in South American camelids. TYRP1 is among one of the major regulators of pigmentation in mammals. DCT is a pigment cell-specific gene that plays an important role in the melanin synthesis pathway and the expression of skin color. RAB38 is involved in the transport of tyrosinase (TYR) and TYRP1, which are key enzymes in melanin production.Methods: Five fleece color tones from 327 alpacas (white, black, brown, gray and light fawn) were investigated to characterize and identify polymorphisms that play a role in coat color. Among the SNPs and Indels identified in the coding region, statistical analysis was performed to determine the association between the polymorphisms and fleece color in camelids, as well as the determination of allelic frequencies.Results: Twenty two polymorphisms in the coding region, seven of them were nonsynonymous, eleven were synonymous, three located in the 5’UTR region and one deletion in the 3’UTR region were identified in the TYRP1 gene; in the DCT gene were identified twenty two polymorphisms, where five of them were non-synonymous, twelve were synonymous, one polymorphism in the 5’UTR region and four in the 3’UTR region; in adition, in the RAB38 gene six polymorphisms were identified, one was nonsynonymous, two were synonymous, in addition to three polymorphisms in the 3’UTR region were found in the RAB38 gene. There were low to moderate polymorphisms in the populations. Significant differences (P<0.001) were found with color fiber in the alpaca populations studied for TYRP1 and DCT genes.

Alpaca (Lama pacos) is a domesticated South American camelid mainly distributed in Peru, although also present in Bolivia, Chile and Ecuador. This species, highly appreciated because of its lustrous and silky natural fibre, has been poorly studied at the genetic level. Characterisation of the genetic diversity of alpaca would be fundamental for gaining new insights into past domestication events as well as for understanding the demographic history of this species. In the present work, we report the mitochondrial genetic variability of alpacas (n = 29) distributed in eight farming areas of the south region of Peru. Sequencing of the D-loop region revealed the existence of 16 haplotypes. Haplotype (Hd) and nucleotide (π) diversities reached values of 0.96 and 0.0456, respectively. Moreover, analysis of the cytochrome b region evidenced the segregation of 15 haplotypes (Hd = 0.946, π = 0.0279). We can conclude that, despite the drastic reduction in the census of alpacas, there is still a considerable level of genetic variation. Median-joining network and neighbour joining phylogenetic analyses showed the existence of two guanaco-like and vicuña-like mitochondrial haplogroups. These results might be explained by the occurrence of ancient hybridisation events between llamas and alpacas with the goal of recovering the alpaca population that was decimated by the Spanish colonisers two centuries ago.

El libro Problemas de Epidemiología Veterinaria constituye una herramienta académica integral, especialmente diseñada para estudiantes de pregrado en Medicina Veterinaria y disciplinas afines. Su propósito es facilitar el aprendizaje activo y significativo de los principios fundamentales de la epidemiología veterinaria, mediante un enfoque práctico, estructurado y altamente didáctico. La obra se organiza en torno a la resolución de más de 50 problemas distribuidos en bloques temáticos esenciales: medidas de frecuencia, medidas de asociación, validación y evaluación de pruebas diagnósticas, investigación de brotes epidémicos y análisis de tasas de mortalidad. Cada sección combina la teoría con ejercicios aplicados, promoviendo una comprensión progresiva de los conceptos y su aplicabilidad en contextos reales de la sanidad animal. Cada capítulo introduce conceptos teóricos esenciales y los aplica inmediatamente a casos reales o simulados, permitiendo al lector ejercitar habilidades de análisis epidemiológico con base en cálculos precisos, interpretación de datos y uso de herramientas estadísticas. Asimismo, se incorporan elementos metodológicos útiles para la enseñanza, la extensión universitaria y la capacitación profesional en salud animal y salud pública veterinaria.

The adiponectin (ADIPOQ) locus is a positional and functional candidate gene for 2 porcine chromosome 13 (SSC13) QTL influencing cholesterol (CHOL) and low-density lipoprotein (LDL) concentrations in 190-d-old pigs. By sequencing 2.37 kb of the pig ADIPOQ cDNA, we have identified 1 c.*1512G > T 3′ untranslated region polymorphism that has been genotyped in a Duroc pig commercial population with records for serum lipid levels at 45 and 190 d of age. Statistical analysis of the data have revealed significant associations between the ADIPOQ genotype and CHOL (P = 0.0040) and LDL (P = 0.0011) concentrations at 190 d but not at 45 d. In family 3, most of the SSC13 QTL effects on LDL levels at 190 d were explained by the ADIPOQ genotype. We also found an association with triglyceride levels at 45 d (P = 0.0060) but not at 190 d. Measurement of allelic mRNA imbalance demonstrated that the G and T alleles are expressed at very similar levels in muscle and fat tissues, indicating that the c.*1512G > T polymorphism does not affect transcript abundance. As a whole, results obtained in the current work as well as previous data gathered in humans and pigs provide evidence that the magnitude of associations between blood lipid phenotypes and candidate loci genotypes may vary depending on the age of the individual, therefore suggesting the existence of dynamic genotype × environment interactions changing on a temporal scale. Copyright © 2014. American Society of Animal Science.