Innovative phenotyping strategies exploiting immune response to heat stress conditions

peer reviewedEvaluating the heat stress status of an animal is a challenge. Indeed, currently, the heat stress status is determined on the basis of a significative change of a response variable known to be correlated with a temperature-humidity related variable. These response variables are, most often, milk yield or similar traits. However, it is known that heat stress has a negative effect on the immune system, but this information is still very little used in the context of heat stress phenotyping. Indeed, only a few studies highlight immune genes involved in heat stress. In addition, these studies provide very little information on the molecular mechanisms that link these genes to the observed phenotype. Immune response based deep-phenotyping strategy would provide a more comprehensive understanding of heat stress and could also serve as a basis for identifying heat stress indicators through genomics

Invited review: From heat stress to disease-Immune response and candidate genes involved in cattle thermotolerance.

peer reviewedHeat stress implies unfavorable effects on primary and functional traits in dairy cattle and, in consequence, on the profitability of the whole production system. The increasing number of days with extreme hot temperatures suggests that it is imperative to detect the heat stress status of animals based on adequate measures. However, confirming the heat stress status of an individual is still challenging, and, in consequence, the identification of novel heat stress biomarkers, including molecular biomarkers, remains a very relevant issue. Currently, it is known that heat stress seems to have unfavorable effects on immune system mechanisms, but this information is of limited use in the context of heat stress phenotyping. In addition, there is a lack of knowledge addressing the molecular mechanisms linking the relevant genes to the observed phenotype. In this review, we explored the potential molecular mechanisms explaining how heat stress affects the immune system and, therefore, increases the occurrence of immune-related diseases in cattle. In this regard, 2 relatively opposite hypotheses are under focus: the immunosuppressive action of cortisol, and the proinflammatory effect of heat stress. In both hypotheses, the modulation of the immune response during heat stress is highlighted. Moreover, it is possible to link candidate genes to these potential mechanisms. In this context, immune markers are very valuable indicators for the detection of heat stress in dairy cattle, broadening the portfolio of potential biomarkers for heat stress

Recent genetic advances on boar taint reduction as an alternative to castration: a review.

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Phosphofructokinase mainly affects glycolysis and influences meat quality in postmortem meat

peer reviewedThe aim of this study was to evaluate the comparative effects of hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK) on glycolysis in postmortem meat. Three specific inhibitors were respectively added to postmortem lamb to produce a HK inhibition (HKI) group, a PFK inhibition (PFKI) group and a PK inhibition (PKI) group. Meat samples that assigned to these three groups and a control (CON) group were stored at 4 °C for 5 d. The results indicated that the activity of HK, PFK and PK were effectively restrained during storage. PFK activity was significantly correlated with lactate content (P 0.05). The myofibrillar fragmentation index of the PFKI and PKI groups were significantly lower than that of the CON and HKI groups (P < 0.05). The degradation levels of troponin T and desmin were the smallest in the PFKI group. The result of the myoglobin spectrum at 540 nm and 580 nm showed a decreasing level of oxymyoglobin after HK, PFK and PK inhibition. In conclusion, PFK showed a more dominant effect on glycolysis than HK and PK in postmortem muscle, which may provide a targeted strategy for meat quality regulation through glycolysis

Effect of Cephalosporin Treatment on the Microbiota and Antibiotic Resistance Genes in Feces of Dairy Cows with Clinical Mastitis.

peer reviewedAntibiotics are frequently used to treat dairy cows with mastitis. However, the potential effects of β-lactam antibiotics, such as cephalosporins, on the fecal microbiome is unknown. The objective was to investigate the effects of ceftiofur and cefquinome on the fecal microbiota and antibiotic resistance genes of dairy cows with mastitis. The fecal samples were collected from 8 dairy cows at the following periods: the start day (Day 0), medication (Days 1, 2, and 3), withdrawal (Days 4, 6, 7, and 8), and recovery (Days 9, 11, 13, and 15). 16S rRNA gene sequencing was applied to explore the changes in microbiota, and qPCR was used to investigate the antibiotic resistance genes. The cephalosporin treatment significantly decreased the microbial diversity and richness, indicated by the decreased Shannon and Chao 1 indexes, respectively (p < 0.05). The relative abundance of Bacteroides, Bacteroidaceae, Bacteroidales, and Bacteroidia increased, and the relative abundance of Clostridia, Clostridiales, Ethanoligenens, and Clostridium IV decreased at the withdrawal period. The cephalosporin treatment increased the relative abundance of β-lactam resistance genes (blaTEM and cfxA) at the withdrawal period (p < 0.05). In conclusion, the cephalosporin treatment decreased the microbial diversity and richness at the medication period, and increased the relative abundance of two β-lactam resistance genes at the withdrawal period

The Influence of Dietary Gallic Acid on Growth Performance and Plasma Antioxidant Status of High and Low Weaning Weight Piglets.

peer reviewedThis study evaluated the effects of dietary gallic acid (GA) on growth performance, diarrhea incidence and plasma antioxidant status of weaned piglets regardless of whether weaning weight was high or low. A total of 120 weaned piglets were randomly allocated to four treatments in a 42-day experiment with a 2 × 2 factorial treatment arrangement comparing different weaning weights (high weight (HW) or low weight (LW), 8.49 ± 0.18 kg vs. 5.45 ± 0.13 kg) and dietary treatment (without supplementation (CT) or with supplementation of 400 mg/kg of GA). The results showed that HW piglets exhibited better growth performance and plasma antioxidant capacity. Piglets supplemented with GA had higher body weight (BW) on day 42 and average daily gain (ADG) from day 0 to 42 compared to the control piglets, which is mainly attributed to the specific improvement on BW and ADG of LW piglets by the supplementation of GA. The decreased values of diarrhea incidence were seen in piglets fed GA, more particularly in LW piglets. In addition, dietary GA numerically reduced malondialdehyde (MDA) content in plasma of LW piglets. In conclusion, our study suggests that dietary GA may especially improve the growth and health in LW weaned piglets

Identifying Molecular Differences in Pigs with Extreme Phenotypes for Weight Gain and Viral Load in Response to PRRS

Blood transcriptome analyses in the early phase after infection with the Porcine Reproductive and Respiratory Syndrome virus (PRRSv) revealed differential gene expression patterns and regulatory networks between pigs with extreme phenotypes for weight gain and viral load. Understanding these differences could lead to identifying biomarkers that would predict which pigs would be more resistant to PRRS

Dietary 25-hydroxy-cholecalciferol and additional vitamin E improve bone development and antioxidant capacity in high-density stocking broilers.

peer reviewedThis study aimed to investigate the effects of diets supplemented with 25-hydroxycholecalciferol [25-(OH)D3] and additional vitamin E on growth performance, antioxidant capacity, bone development, and carcass characteristics at different stocking densities on commercial broiler farms. A total of 118,800 one-day-old Arbor Acres broilers were assigned to a 2 × 2 factorial treatment consisting of two dietary vitamin levels (5,500 IU vitamin D3 and 60 IU vitamin E: normal diet, using half 25-(OH)D3 as a source of vitamin D3 and an additional 60 IU of vitamin E: 25-(OH)D3+VE diet) and two stocking densities (high density of 20 chickens/m2: HD and 16 chickens/m2: LD). The experiment lasted for 42 d. The results showed that high-density stocking negatively affected the growth performance of broilers during the first four weeks, whereas the vitamin diet treatment significantly improved the feed conversion ratios (FCR) during the last 2 wk. Vitamin diets increased catalase at 14 and 42 d, and the glutathione peroxidase (GSH-px) levels at 42 d in high-density-stocked broilers. The interaction showed that serum vitamin E levels were significantly improved at 28 d of age in high-density-stocked broilers as a result of the vitamin diets. Stocking density and dietary treatments were found to significantly affect bone development, with the vitamin diet significantly increasing metatarsal length and femoral bone strength in broilers from high-density stocking density at 28 d of age. High stocking density increased the proportion of leg muscles and meat yield per square meter. In general, 25-(OH)D3 and additional vitamin E suppressed oxidative stress and ameliorated the negative effects of high-density stocking on bone development in a commercial chicken farm setting. Vitamin diets improved the FCR of broilers, while high-density stocking resulted in better economic outcomes.High-density stocking is often associated with animal welfare risks in broilers, mainly in terms of oxidative stress and bone development. Nevertheless, farming at too low a density remains for the most part economically unviable. Modulation of antioxidant capacity and bone development by nutritional strategies in high-density-farmed broilers has proven an effective tool in developing countries. Therefore, the present study investigated the effects of applying diets with a higher biological potency of vitamin D3 25-hydroxycholecalciferol [25-(OH)D3] and a higher concentration of vitamin E on broiler production performance, antioxidant capacity and meat production performance at different densities of stocking under commercial farming conditions. The results indicated that the vitamin dietary treatments suppressed oxidative stress and ameliorated the negative effects of high-density farming on bone development

Whole blood microarray analysis of pigs showing extreme phenotypes after a porcine reproductive and respiratory syndrome virus infection

Citation: Schroyen, M., Steibel, J. P., Koltes, J. E., Choi, I., Raney, N. E., Eisley, C., . . . Tuggle, C. K. (2015). Whole blood microarray analysis of pigs showing extreme phenotypes after a porcine reproductive and respiratory syndrome virus infection. Bmc Genomics, 16(1). doi:10.1186/s12864-015-1741-8Background: The presence of variability in the response of pigs to Porcine Reproductive and Respiratory Syndrome virus (PRRSv) infection, and recent demonstration of significant genetic control of such responses, leads us to believe that selection towards more disease resistant pigs could be a valid strategy to reduce its economic impact on the swine industry. To find underlying molecular differences in PRRS susceptible versus more resistant pigs, 100 animals with extremely different growth rates and viremia levels after PRRSv infection were selected from a total of 600 infected pigs. A microarray experiment was conducted on whole blood RNA samples taken at 0, 4 and 7 days post infection (dpi) from these pigs. From these data, we examined associations of gene expression with weight gain and viral load phenotypes. The single nucleotide polymorphism (SNP) marker WUR10000125 (WUR) on the porcine 60 K SNP chip was shown to be associated with viral load and weight gain after PRRSv infection, and so the effect of the WUR10000125 (WUR) genotype on expression in whole blood was also examined. Results: Limited information was obtained through linear modeling of blood gene differential expression (DE) that contrasted pigs with extreme phenotypes, for growth or viral load or between animals with different WUR genotype. However, using network-based approaches, molecular pathway differences between extreme phenotypic classes could be identified. Several gene clusters of interest were found when Weighted Gene Co-expression Network Analysis (WGCNA) was applied to 4dpi contrasted with 0dpi data. The expression pattern of one such cluster of genes correlated with weight gain and WUR genotype, contained numerous immune response genes such as cytokines, chemokines, interferon type I stimulated genes, apoptotic genes and genes regulating complement activation. In addition, Partial Correlation and Information Theory (PCIT) identified differentially hubbed (DH) genes between the phenotypically divergent groups. GO enrichment revealed that the target genes of these DH genes are enriched in adaptive immune pathways. Conclusion: There are molecular differences in blood RNA patterns between pigs with extreme phenotypes or with a different WUR genotype in early responses to PRRSv infection, though they can be quite subtle and more difficult to discover with conventional DE expression analyses. Co-expression analyses such as WGCNA and PCIT can be used to reveal network differences between such extreme response groups. © 2015 Schroyen et al