Characterization of Flagellotropic, Chi-Like Salmonella Phages Isolated from Thai Poultry Farms.

Despite a wealth of knowledge on Salmonella phages worldwide, little is known about poultry-associated Salmonella phages from Thailand. Here, we isolated 108 phages from Thai poultry farms that infect Salmonellaenterica serovar Typhimurium. Phages STm101 and STm118 were identified as temperate Siphoviridae phages. Genome sequencing and analyses revealed these phages share approximately 96% nucleotide sequence similarity to phage SPN19, a member of the Chi-like virus genus. PCR amplification of the gene encoding capsid protein E of the Chi-like phage was positive for 50% of phage isolates, suggesting a predominance of this phage type among the sampled poultry farms. In addition to the flagella, two phages required the lipopolysaccharide to infect and lyse Salmonella. Furthermore, phylogenomic analysis demonstrated that phages STm101 and STm118 formed a monophyletic clade with phages isolated from Western countries, but not from closer isolated phages from Korea. However, further investigation and more phage isolates are required to investigate possible causes for this geographic distribution.

Encapsulating Viability of Multi-strain Lactobacilli as Potential Probiotic in Pigs.

Important aspects of the selection of probiotics to be used for mixing in animal feed include host species specificity and probiotic cell survival during production and storage of their products. The research was to screen and investigate some probiotic properties of lactic acid bacteria (LAB) isolated from pig fecal samples. One hundred and thirty-eight representative LAB isolates, which were isolated from 51 pig fecal samples, were tested for acid and bile tolerance, antimicrobial susceptibility, antibacterial activity, potential adhesion to the cell surface, and survival rates when stored in varied microencapsulation forms: freeze-dried, spray-dried, and micro-beads. The antibacterial activity results of the ten LAB isolates, which were acid- (pH 2, 3 h) and bile- (50% (v/v) fresh pig bile, 8 h) tolerant and suitable for resisting the five antibiotics commonly used for treating pig infections with pathogenic indicator strains, showed that three isolates (L21, L80, L103) had strong inhibition to Escherichia coli, Salmonella group B, and Salmonella group D using co-culturing and agar spot assays. The three isolates had high hydrophobicity (65-73%) and did not show antagonistic growth against each other. All three selected isolates had greater than 80% survival in freeze-dried and micro-bead forms at 25-30 °C after 2 days of storage (80.4-86.75%, 7.31-7.89 log CFU/ml). Sequence analysis of the 16S rRNA genes demonstrated that the three isolates belong to Lactobacillus plantarum (strain L21 and strain L80) and L. paraplantarum (strain L103). The single and multiple strains of these bacteria may have potential use as probiotics in pig diets.

The identification of novel regions for reproduction trait in Landrace and Large White pigs using a single step genome-wide association study.

OBJECTIVE: The purpose of this study was to investigate a single step genome-wide association study (ssGWAS) for identifying genomic regions affecting reproductive traits in Landrace and Large White pigs. METHODS: The traits included the number of pigs weaned per sow per year (PWSY), the number of litters per sow per year (LSY), pigs weaned per litters (PWL), born alive per litters (BAL), non-productive day (NPD) and wean to conception interval per litters (W2CL). A total of 321 animals (140 Landrace and 181 Large White pigs) were genotyped with the Illumina Porcine SNP 60k BeadChip, containing 61,177 single nucleotide polymorphisms (SNPs), while multiple traits single-step genomic BLUP method was used to calculate variances of 5 SNP windows for 11,048 Landrace and 13,985 Large White data records. RESULTS: The outcome of ssGWAS on the reproductive traits identified twenty-five and twenty-two SNPs associated with reproductive traits in Landrace and Large White, respectively. Three known genes were identified to be candidate genes in Landrace pigs including retinol binding protein 7, and ubiquitination factor E4B genes for PWL, BAL, W2CL, and PWSY and one gene, solute carrier organic anion transporter family member 6A1, for LSY and NPD. Meanwhile, five genes were identified to be candidate genes in Large White, two of which, aldehyde dehydrogenase 1 family member A3 and leucine rich repeat kinase 1, associated with all of six reproduction traits and three genes; retrotransposon Gag like 4, transient receptor potential cation channel subfamily C member 5, and LHFPL tetraspan subfamily member 1 for five traits except W2CL. CONCLUSION: The genomic regions identified in this study provided a start-up point for marker assisted selection and estimating genomic breeding values for improving reproductive traits in commercial pig populations.

In vitro and in vivo evaluation of protein quality of enzymatic treated feather meals.

Feeding trials were designed to evaluate the nutritive value of feather meal treated by K6 and K82 keratinase. There were five treatments in feather meal preparation: CFM (non-enzymatically treated feather meal), K6FM (K6 keratinase treated feather meal), K82FM (K82 keratinase treated feather meal), K6:K82FM [K6 and K82 keratinase (5:1) treated feather meal] and CMFM (commercial enzyme treated feather meal). The pepsin digestibility of CFM (70 %) and CMFM (68 %) was significantly higher than K6FM (60 %), K82FM (61 %) and K6:K82FM (63 %). Total amino acid content of K82FM (89.65/100 g) was the highest compared with the other treatments. The nutrient digestibility of the feather meals was determined for broiler chicks between 21 and 27 days old. The apparent nitrogen retention of K82FM (85.82 %) and K6FM (77.31 %) was significantly higher than K6:K82FM (55.42 %), CMFM (45.70 %) and CFM (48.16 %). The apparent metabolisable energy (AMEn) was not significantly different between the feather meal treatments, although K82FM, K6FM and K6:K82FM showed AMEn higher than CMFM and CFM. The results indicated that both K6 and K82 keratinase had a positive effect on the protein quality of the feather meal produced by the enzymatic-hydrothermal method.