Growing interest has been emerging on the need to monitor the genetic integrity of the European Apis mellifera subspecies that could be threatened by the human-mediated dispersion of non-native populations and lines. Mitochondrial DNA (mtDNA) lineages can provide useful information for this purpose. In this study, we took advantage of the environmental DNA (eDNA) contained in the honey, which can be analyzed to detect the main groups of mitotypes of the honey bees that produced it. In this study, we applied this eDNA to produce a distribution map all over the Italian peninsula and the two major islands (Sicily and Sardinia) of the following three honey bee mtDNA lineages: A, C and M. A total of 607 georeferenced honey samples, produced in all Italian regions, was analyzed to detect these lineages. The A lineage was widespread in Sicily, as expected, considering that A. m. siciliana carries the African lineage. Surprisingly, this lineage was also reported in about 14% of all other samples produced in almost all continental regions, and in Sardinia. The applied method obtained an updated distribution map of honey bee mtDNA lineages that could be useful to design policies for the conservation of Italian honey bee genetic resources.

Breeding animals to produce more robust and disease-resistant pig populations becomes a complementary strategy to the more conventional methods of biosecurity and vaccination. The objective of this study was to explore the ability of a panel of genetic markers and immunity parameters to predict the survival rates during a natural PRRSV outbreak. Ten-week-old female Duroc pigs (n = 129), obtained from 61 sows and 20 boars, were naturally infected with a highly pathogenic PRRSV genotype 1 strain. Prior to infection, piglets were screened for immunity parameters (IgG levels in plasma and SOX13 mRNA expression in blood) and genetic markers previously associated to PRRSV immune response and immunity traits. Additionally, the 20 boars were genotyped with a panel of 132 single nucleotide polymorphisms (SNPs). Survival analysis showed that mortality was significantly higher for animals with low basal IgG levels in plasma and/or high SOX13 mRNA expression in blood. The genotypes of sires for SNPs associated with IgG plasma levels, CRP in serum, percentage of γδ T cells, lymphocyte phagocytic capacity, total number of lymphocytes and leukocytes, and MCV and MCH were significantly associated with the number of surviving offspring. Furthermore, CD163 and GBP5 markers were also associated to piglet survival. The effects of these SNPs were polygenic and cumulative, survival decreased from 94 to 21% as more susceptible alleles were accumulated for the different markers. Our results confirmed the existence of genetic variability in survival after PRRSV infection and provided a set of genetic markers and immunity traits associated with PRRS resistance.

Fatty acids are a diverse group of lipid molecules that play essential roles in energy metabolism, cellular differentiation and signalling mechanisms. The objective of this study was to explore the genetic determinism of fatty acid composition across backfat, liver, muscle and plasma and its association with immunocompetence and performance traits in pigs. Fatty acid profiles were analysed in 432 commercial Duroc pigs. High heritability was found for most fatty acids in backfat and for long-chain polyunsaturated fatty acids in liver, while muscle and plasma showed medium to low heritabilities. Strong genetic correlations were observed between the relative abundance of γδ T cells and cytotoxic T cells with the lipid profiles of backfat and muscle, with opposite patterns between these cell types. Muscle unsaturated fatty acids were positively correlated with phagocytosis capacity and red blood cell traits, and negatively with plasma cortisol. Acute phase proteins showed similar correlations with liver lipids but opposite with some plasma fatty acids. Lean meat and fatness traits were particularly associated to the backfat fatty acid composition, showing opposite correlation patterns, while pH was strongly correlated with the liver fatty acid profile. These results demonstrated the specific lipid profiles of backfat, liver, muscle and plasma, their genetic determinism, and their relationships with immunity and production traits.

Background: The modulation, activation, and differentiation of several immune cells is highly dependent on lipid metabolism. The objective of this study was to analyse the genetic determinism of the porcine plasma lipidome and its association to the animal immune capacity and production performance. The analysis of the blood lipidome of 300 60-day-old Duroc pigs allowed semi-quantification of 982 circulating lipid molecules. We evaluated the genetic determinism of the lipidome abundances, as well as their phenotypic and genetic correlations with health, stress, and carcass phenotypes. Results: Triacylglycerols were the most abundant lipid class among the plasma lipid features, followed by glycerophosphocholines, glycerophosphoethanolamines, diacylglycerols, and fatty acids/esters. Lipidome abundances showed low to moderate phenotypic correlations with the health and production traits, which clustered in two groups with opposite phenotypic correlation patterns with the lipidome. Mean heritability estimates for the circulating lipids abundance was generally low, but 184 lipid molecules showed significant heritability ranging between 0.25 and 0.85. At the genetic level, the percentage and phagocytic capacity of lymphocytes, the proportion of γδ T lymphocytes, and the cortisol concentration in hair were especially correlated with the lipidome, showing more than 200 significant genetic correlations with different lipidic compounds. Putative identification of associated metabolites by mass similarity revealed a large presence of phospholipids and glycerolipids among lipid molecules genetically correlated with immunity traits. Regarding production traits, fatness and lean meat measures showed an opposite pattern of genetic correlations with the porcine lipidome. Lipids positively correlated with fatness were mainly composed of diacyl- and triacyl-glycerides, while potential ceramides and phospholipids were more abundant among the lipids positively correlated with lean meat content at the genetic level. Conclusions: Our results demonstrate a genetic determinism of the porcine blood lipidomic profile and suggest genetic correlations of the lipidome abundances with health and production performance phenotypes. We identify potential lipid biomarkers for assessing animal health and productivity.