The pig, Sus scrofa, is a foreign species to the American continent. Although pigs originally introduced in the Americas should be related to those from the Iberian Peninsula and Canary islands, the phylogeny of current creole pigs that now populate the continent is likely to be very complex. Because of the extreme climates that America harbors, these populations also provide a unique example of a fast evolutionary phenomenon of adaptation. Here, we provide a genome wide study of these issues by genotyping, with a 60k SNP chip, 206 village pigs sampled across 14 countries and 183 pigs from outgroup breeds that are potential founders of the American populations, including wild boar, Iberian, international and Chinese breeds. Results show that American village pigs are primarily of European ancestry, although the observed genetic landscape is that of a complex conglomerate. There was no correlation between genetic and geographical distances, neither continent wide nor when analyzing specific areas. Most populations showed a clear admixed structure where the Iberian pig was not necessarily the main component, illustrating how international breeds, but also Chinese pigs, have contributed to extant genetic composition of American village pigs. We also observe that many genes related to the cardiovascular system show an increased differentiation between altiplano and genetically related pigs living near sea level.

Yaneselli KM, et al. J Vet Sci. 2018 Jan;19(1):13-20. https://doi.org/10.4142/jvs.2018.19.1.13

Bovine Leukemia Virus (BLV) produces disorders on the immune system in naturally infected animals, which may counteract the development of immunity after vaccination. The aim of this study was to investigate whether healthy and BLV infected cattle elicited similar humoral responses after foot and mouth disease (FMD) immunization. In a field study, 35 Holstein heifers were selected based on their BLV serological status and immunized with a single dose of a commercial bivalent oil-based FMD vaccine. Serum samples were collected at 0, 15, 60, 165 and 300 days post vaccination (dpv). Total anti-A24/Cruzeiro antibodies, IgM, IgG1, IgG2 titers and avidity index of specific antibodies were determined by ELISA. Although only marginally significant differences were found between groups in terms of total antibodies, anti-FMD IgM and IgG1 titers were significantly lower in heifers infected with BLV at the 15 dpv (p < 0.01). Animals that became infected during the study did not show differences to the BLV negative group. Cattle infected with BLV at the time of immunization may elicit a low-magnitude serological response to a commercial Foot-and-mouth disease vaccine.

In this study, we genetically characterized the Uruguayan pig breed Pampa Rocha. Genetic variability was assessed by analyzing a panel of 25 microsatellite markers from a sample of 39 individuals. Pampa Rocha pigs showed high genetic variability with observed and expected heterozygosities of 0.583 and 0.603, respectively. The mean number of alleles was 5.72. Twenty-four markers were polymorphic, with 95.8% of them in Hardy Weinberg equilibrium. The level of endogamy was low (F_IS = 0.0475). A factorial analysis of correspondence was used to assess the genetic differences between Pampa Rocha and other pig breeds; genetic distances were calculated, and a tree was designed to reflect the distance matrix. Individuals were also allocated into clusters. This analysis showed that the Pampa Rocha breed was separated from the other breeds along the first and second axes. The neighbour-joining tree generated by the genetic distances D_A showed clustering of Pampa Rocha with the Meishan breed. The allocation of individuals to clusters showed a clear separation of Pampa Rocha pigs. These results provide insights into the genetic variability of Pampa Rocha pigs and indicate that this breed is a well-defined genetic entity.