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A new methodology is proposed for ractopamine residue analysis in pork. It consists of enzyme-mediated digestion and deconjugation steps; modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction; and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In brief, the samples were digested with protease and then deconjugated with β-glucuronidase enzyme; they were then subjected to extraction and cleanup by QuEChERS and underwent sequential analysis by LC-MS/MS. The method performance was evaluated in accordance to the validation guidelines regulated by the Brazilian Ministry of Agriculture and Food Supply. The limit of detection was 0.15 μg/kg and limit of quantification was 0.5 μg/kg. When the method was applied to real samples, ractopamine residue was found in concentrations (up to 7.86 μg/kg) below international recommendation limits up to 10 μg/kg. The method is sensitive, accurate, quick, simple, and suitable for routine analysis; therefore, it is a monitoring tool that may be adopted by laboratories to achieve compliance levels.

Locomotor problems have a great economic impact on world poultry production, because difficulty of locomotion leads to a decrease in animal performance and an increase in partial or total carcass condemnation. In addition, locomotor problems greatly affect the chicken welfare. Bacterial Chondronecrosis with Osteomyelitis (BCO) or Femoral Head Necrosis (FHN) is responsible for altering the bone tissue degenerating the cartilage and femoral epiphysis. Despite its not well known etiology, it is believed that this disorder causes a decrease in tissue vascularization, interfering with blood flow and affecting the angiogenesis processes, predisposing broilers to bone problems. Genetic factors associated to rapid growth rate of the modern broilers are pointed out as predisposing chickens to BCO. Therefore, the aim of this study was to evaluate the expression of 13 functional candidate genes in femur samples of normal and BCO-affected commercial broilers at 35 days of age to clarify the genetic mechanisms involved in the BCO in chickens. From the 13 genes studied, 10 were differentially expressed (DE) between groups: ADIPOQ, PRRX1, ANGPTL5, GFRA2, SFRP5, COL14A1, ABI3BP, ANGPTL7, COL8A1 and SLC30A10, which were downregulated in broilers affected by BCO, except for the SLC30A10, which was upregulated in the affected chickens. Although their functions are not well established in chickens, these genes participate in important biological processes in mammals, such as osteogenesis, formation of connective tissue and collagen production, and general bone development. The genes expression pattern, their functions and interactions, altogether, pointed out those DE genes as strong candidates to be involved with BCO in broiler chickens. The DE genes evaluated in this study might contribute to tissue necrosis, which could lead to the development of Bacterial Chondronecrosis with Osteomyelitis in chickens. Those should be further investigated aiming to reduce this bone anomaly in broilers.

A genome-wide association study for immune response to influenza vaccination in a crossbred swine population was conducted. Swine influenza is caused by influenza A virus (FLUAV) which is considered one of the most prevalent respiratory pathogens in swine worldwide. The main strategy used to control influenza in swine herds is through vaccination. However, the currently circulating FLUAV subtypes in swine are genetically and antigenically diverse and their interaction with the host genetics poses a challenge for the production of efficacious and cross-protective vaccines. In this study, 103 pigs vaccinated with an inactivated H1N1 pandemic virus were genotyped with the Illumina PorcineSNP60V2 BeadChip for the identification of genetic markers associated with immune response efficacy to influenza A virus vaccination. Immune response was measured based on the presence or absence of HA (hemagglutinin) and NP (nucleoprotein) antibodies induced by vaccination and detected in swine sera by the hemagglutination inhibition (HI) and ELISA assays, respectively. The ELISA test was also used as a measurement of antibody levels produced following the FLUAV vaccination. Associations were tested with x(2) test for a case and control data and using maximum likelihood method for the quantitative data, where a moderate association was considered if p5×10(-5). When testing the association using the HI results, three markers with unknown location and three located on chromosomes SSCX, SSC14 and SSC18 were identified as associated with the immune response. Using the response to vaccination measured by ELISA as a qualitative and quantitative phenotype, four genomic regions were associated with immune response: one on SSC12 and three on chromosomes SSC1, SSC7, and SSC15, respectively. Those regions harbor important functional candidate genes possibly involved with the degree of immune response to vaccination. These results show an important role of host genetics in the immune response to influenza vaccination. Genetic selection for pigs with better response to FLUAV vaccination might be an alternative to reduce the impact of influenza virus infection in the swine industry. However, these results should to be validated in additional populations before its use.