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The effects of meat pH on muscle fiber characteristics, cortisol level, and Tenascin C (TNC) gene expression were examined. The muscle samples (n=100) were randomly collected from the Longissimus thoracis et lumborum (LTL) to determine meat pH at 24 hours (meat pH24h) postmortem. Muscle samples (five samples per group) with divergent meat pH levels (low versus high) were selected to study muscle fiber characteristics and mRNA expression based on quantitative real-time polymerase chain reaction (qRT-PCR). Blood samples (five samples per group) of the two meat pH levels were taken for serum cortisol analysis. The results showed that there was no significant differences between the groups for the muscle fiber characteristics of total number of fibers, muscle fiber diameter, cross-section area, perimysium thickness, and endomysium thickness. Different meat pH24h values did not affect the cortisol level. The mRNA expression of the TNC gene was significantly (p<0.05) downregulated in the low meat pH24h group compared to the high meat pH24h group. In conclusion, meat pH24h was unrelated to the cortisol level and muscle fiber characteristics. However, the TNC gene might play a role in meat pH24h in pigs. [ABSTRACT FROM AUTHOR]

Background and Aim: Toll-like receptors (TLRs) play crucial roles in the early phase of infection in the innate immune response against bacteria, viruses, fungi, and parasites. Lipopolysaccharide-induced tumor necrosis factor-α factor (LITAF) is an essential transcription factor that regulates the immune system, apoptosis, and inflammatory cytokines. This study aimed to determine the hematological profile reflecting the immune response related to TLR2 and TLR4 and LITAF gene expression in Thai indigenous chickens., Materials and Methods: Blood samples (2 mL) were randomly obtained from three chicken breeds (black-boned chicken, Fah Luang chicken, and Pradu Hang Dam chicken) at 16 weeks of age (n = 5 per breed). The hematological profile and mRNA expression within the peripheral blood mononuclear cells (PBMCs) were determined by hematological analysis and quantitative real-time polymerase chain reaction (qRT-PCR)., Results: The hematological profile differed significantly in terms of red blood cells (RBCs), hemoglobin, and white blood cells (WBCs) (p < 0.05). Black-boned chicken and Fah Luang chicken had lower RBC levels than Pradu Hang Dam chicken. Fah Luang chicken had lower hemoglobin than Pradu Hang Dam chicken. However, Fah Luang chicken had higher WBC levels than Pradu Hang Dam chicken. Hematocrit, heterophils, basophils, eosinophils, lymphocytes, and monocytes did not differ significantly among the groups (p > 0.05). According to qRT-PCR, the expression of the TLR2 gene did not differ significantly among the groups (p > 0.05), while TLR4 and LITAF gene expression did (p < 0.05). Toll-like recepto r 4 and LITAF genes were most highly expressed in Fah Luang chicken., Conclusion: The PBMCs of Thai indigenous chickens showed evidence of TLR4 and LITAF gene expression, with higher expression levels observed in Fah Luang chicken. From this preliminary study, it is concluded that TLR4 and LITAF genes might play roles in the main immune system response in Thai indigenous chickens., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Tantikositruj, et al.)

Background and Aim: Antimicrobial resistance (AMR) is a global problem that affects human and animal health, and eggs can act as a vehicle for pathogenic and non-pathogenic resistant bacteria in the food chain. Escherichia coli is an indicator of food contamination with fecal materials as well as the occurrence and levels of AMR. This study aimed to investigate the presence of AMR, integrons, and virulence genes in E. coli isolated from eggshell samples of three egg production systems, from supermarkets in Thailand., Materials and Methods: A total of 750 hen's egg samples were purchased from supermarkets in Phayao Province: Cage eggs (250), free-range eggs (250), and organic eggs (250). Each sample was soaked in buffered peptone water (BPW), and the BPW samples were incubated at 37°C for 18-24 h. All samples were tested for E. coli by the standard conventional culture method. Then, all identified E. coli were tested for antimicrobial susceptibility to 15 antimicrobial agents by the agar disk diffusion method. All E. coli strains were subsequently found to have virulence genes and Classes 1 and 2 integrons by polymerase chain reaction., Results: Among the eggshell samples, 91 samples were identified as having E. coli (cage eggs, 24 strains; free-range eggs, 27 strains; and organic eggs, 40 strains). Then, among the E. coli strains, 47 (51.6%) were positive for at least one virulence gene. The proportion of AMR in the eggshell samples was 91.2% (83/91), and streptomycin (STR), ampicillin (AMP), and tetracycline (TET) had a high degree of resistance. Among the E. coli strains, 27 (29.7%) strains were positive for class 1 or 2 integrons, and integron-positive strains were commonly found in STR-, AMP-, and TET-resistant strains. Multidrug resistance (MDR) was detected in 57.1% (52/91) of the E. coli strains, with STR-AMP-TET (5.5%) as the most frequent pattern. The proportion of MDR in cage eggs was 75.0% (18/24), which was higher than in both free-range and organic eggs. On the other hand, 53.2% (25/47) of E. coli carrying virulence genes had MDR, distributed across the production systems as follows: Cage eggs, 76.9% (10/13); free-range eggs, 63.6% (7/11); and organic eggs, 34.8% (8/23)., Conclusion: Escherichia coli was detected in eggshell samples from all three egg production systems. The high level of virulence genes, AMR, and integrons indicated the possibility of dissemination of AMR among pathogenic and commensal E. coli through eggshells. These findings could be a major concern to farmers, food handlers, and consumers, especially regarding raw egg consumption., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Siriphap, et al.)

Objective: An experiment was conducted to study the blood haematology, muscle pH, and serum cortisol changes in pigs with different levels of drip loss., Methods: Two groups (low and high) of 20 animals were selected from 100 pigs based on drip loss. All [Duroc× (Large White×Landrace)] pigs were slaughtered according to standard slaughtering procedures. At exsanguinations, blood samples were taken for the haematological parameters and serum cortisol analysis. The muscle samples were taken from longissimus dorsi muscle to evaluate the muscle pH and drip loss., Results: Haematological parameters of low drip loss group showed higher content of white blood cells and monocytes than high drip loss group (p<0.05). The low drip loss group had higher muscle pH at 45 min (p<0.05) and 24 h (p<0.001) post-mortem than the high drip loss group. However, there was no significant difference in serum cortisol levels (p>0.05)., Conclusion: Drip loss is mainly affected by the muscle pH decline after slaughter and also might be affected by white blood cells and monocytes.

The present study was aimed to determine the association between metalloproteinase 3 (MMP3), transforming growth factor beta 1 (TGFβ1) and collagen type X alpha I (COL10A1) gene polymorphisms with traits related to leg weakness in pigs. Three hundred Duroc × Pietrain cross breds (DuPi) and 299 pigs of a commercial population (CP) were used for the experiment. DuPi animals were examined for 10 different traits describing leg and feet structure, osteochondrosis (OC) scores and bone density status. Data of OC score at condylus medialis humeri, condylus medialis femoris and distal epiphysis ulna regions of CP were used for association analysis. Significant association (P < 0.05) was found for MMP3 SNP (g.158 C>T) with OC at head of femur and bone mineral density in the DuPi population. Association (P < 0.05) was found between SNP of TGFβ1 (g.180 G>A) with rear leg score and the principle component denoting both OC and feet and leg scores in the DuPi population. No association was found between COL10A1 (g.72 C>T) and leg weakness related traits. The associations of SNPs with OC traits could not be confirmed in the commercial population. Expression analysis of the three candidate genes was performed to compare between healthy and OC. TGFβ1 was found to be highly expressed (P < 0.05) in the OC compared to healthy cartilages, but no significant different expressions were observed for MMP3 and COL10A1 genes. The present finding suggested that TGFβ1 and MMP3 genes variants have an effect on some of the leg weakness related traits.

Background: Leg weakness issues are a great concern for the pig breeding industry, especially with regard to animal welfare. Traits associated with leg weakness are partly influenced by the genetic background of the animals but the genetic basis of these traits is not yet fully understood. The aim of this study was to identify quantitative trait loci (QTL) affecting leg weakness in pigs., Methods: Three hundred and ten F₂ pigs from a Duroc × Pietrain resource population were genotyped using 82 genetic markers. Front and rear legs and feet scores were based on the standard scoring system. Osteochondrosis lesions were examined histologically at the head and the condylus medialis of the left femur and humerus. Bone mineral density, bone mineral content and bone mineral area were measured in the whole ulna and radius bones using dual energy X-ray absorptiometry. A line-cross model was applied to determine QTL regions associated with leg weakness using the QTL Express software., Results: Eleven QTL affecting leg weakness were identified on eight autosomes. All QTL reached the 5% chromosome-wide significance level. Three QTL were associated with osteochondrosis on the humerus end, two with the fore feet score and two with the rear leg score. QTL on SSC2 and SSC3 influencing bone mineral content and bone mineral density, respectively, reached the 5% genome-wide significance level., Conclusions: Our results confirm previous studies and provide information on new QTL associated with leg weakness in pigs. These results contribute towards a better understanding of the genetic background of leg weakness in pigs.

Osteochondrosis (OC) or leg weakness is an economically important disease of young fast growing pigs and is a concern of animal welfare. The etiology and pathogenesis of osteochondrosis is not fully understood yet, but any abnormalities in the formation of hypertrophic chondrocytes and disrupted blood supply to the growth cartilage are very important predisposing factors. Matrix gla protein (MGP) as a potential calcification inhibitor of extracellular matrix might contribute to the development of OC. Molecular characterization, polymorphisms analysis, methylation at promoter region and expression of MGP gene and protein were performed in both healthy and OC cartilage collected from a DurocxPietrain resource population. The porcine MGP gene consists of 4 exons and 3 introns. The full-length MGP cDNA isolated from articular cartilage consists of 606 bp with a 69-bp 5' UTR, a 312-bp open reading frame with a start codon, a 225-bp 3' UTR. Three single-nucleotide polymorphisms (SNP) were detected in the intron 1 (A-115G, C-1073T and C-1135A) and one in the 3'UTR (C-3767T). The relative abundance of MGP mRNA was lower (P<0.05) in OC compared with healthy cartilage. Moreover, the intensity of MGP band was lower (P<0.05) in OC group when quantified by western blot. Furthermore, one CpG region was identified in MGP promoter and DNA methylation of three CG sites were higher in OC compared with normal cartilage. This suggested that the high DNA methylation at specific CG sites in the MGP promoter might be involved in the down regulation of MGP in OC. Immunofluorescence of normal cartilage collected from pigs of different ages revealed that MGP signals were higher in younger pigs and decreased in the older pigs. The MGP protein was expressed more near to the cartilage canals. These results suggest that the MGP gene might be a potential candidate gene for the development of OC in pigs., (Copyright 2010 Elsevier B.V. All rights reserved.)