Effects of antibiotics on shedding of salmonella typhimurium in experimentally inoculated pigs

The objective of this experiment was to determine if antibiotics used as feed additives and disease treatment for livestock affect duration of shedding and colonization of tissues with Salmonella typhimurium in pigs. No statistically significant difference was detected in duration or amount of shedding of S. typhimurium between pigs receiving antibiotics and control pigs. Antibiotics prevented colonization of tissues by S. typhimurium. The odds (OR= .02) of isolating S. typhimurium in at least one of four tissues examined were significantly less from pigs treated with antibiotics than from control pigs (two-tailed Fisher exact test, P= .009)

Effects of tetracycline on shedding of susceptible and resistant salmonella spp. experimentally inoculated into pigs

The objective of this experiment was to study the influence of tetracycline on the transfer of antibiotic resistance in an in vivo swine model experimentally infected with antibiotic-resistant and antibiotic susceptible Salmonella spp. Tetracycline reduced the amount and duration of shedding of tetracycline- susceptible Salmonella. However, tetracycline had no effect on shedding of resistant Salmonella. We also have evidence that resistance was transferred from the resistant to the susceptible strain of Salmonella

Effects of adding cracked corn to a pelleted supplement for nursery and finishing pigs

Three experiments were conducted to determine the effects of supplementing cracked corn into diets of nursery and finishing pigs. In Exp. 1, 144 pigs were used in a 28-d trial. Pigs (PIC TR4 × 1050; initially 16.5 lb) were weaned and allotted with 6 pigs per pen (3 barrows and 3 gilts) and 6 pens per treatment. All pigs were fed a common diet for 7 d postweaning and the experimental diets for the next 28 d. Treatments were corn-soybean meal-based in the form of mash, pellets, and pellets with 100% of the corn either ground (618 μm) or cracked (3,444 μm) and blended into the diet after the rest of the formulation (the supplement) had been pelleted. Overall (d 0 to 28), ADG and F/G improved when pigs were fed the mash control compared to the pelleted diets (P < 0.001); however, this response was caused by the poor performance of pigs fed the supplement treatments, with the pigs fed the complete pellets having improved (P < 0.01) ADG and F/G compared with pigs fed the pelleted supplement blended with ground and cracked corn. Finally, pigs fed the supplement blended with cracked corn had numerically lower (P < 0.11) ADG and poorer (P < 0.001) F/G compared to those fed the supplement blended with ground corn. In Exp. 2, 224 nursery pigs (initially 16.3 lb) were used with 7 barrows or 7 gilts per pen and 8 pens per treatment. Treatments were corn-soybean meal-based and fed as mash, pellets, and pellets with 50% of the corn either ground (445 μm) or cracked (2,142 μm) and blended with the pelleted supplement. Pigs fed mash had improved (P < 0.03) ADG and F/G compared with pigs fed the other treatments; however, this resulted from adding ground or cracked corn outside the pellets (complete pellets vs. pelleted supplement with corn, P < 0.01). In Exp. 3, 252 finishing pigs (initially 88.2 lb) were used with 7 pigs per pen and 9 pens per treatment. The treatments were the same as Exp. 2. Pigs fed mash had lower (P < 0.004) ADG compared with pigs fed diets with pellets. Pigs fed complete pellets had improved (P < 0.03) ADG and F/G compared with pigs fed corn and the pelleted supplement. Also, pigs fed the supplement blended with cracked corn had greater (P < 0.02) ADG than pigs fed the supplement blended with ground corn. Pelleting the diet led to an increase (P < 0.05) in ulceration scores; however, these negative effects on ulcer scores were reduced (P < 0.001) by cracking 50% of the corn and adding it postpellet

A map of human genome variation from population-scale sequencing

The 1000 Genomes Project aims to provide a deep characterization of human genome sequence variation as a foundation for investigating the relationship between genotype and phenotype. Here we present results of the pilot phase of the project, designed to develop and compare different strategies for genome-wide sequencing with high-throughput platforms. We undertook three projects: low-coverage whole-genome sequencing of 179 individuals from four populations; high-coverage sequencing of two mother-father-child trios; and exon-targeted sequencing of 697 individuals from seven populations. We describe the location, allele frequency and local haplotype structure of approximately 15 million single nucleotide polymorphisms, 1 million short insertions and deletions, and 20,000 structural variants, most of which were previously undescribed. We show that, because we have catalogued the vast majority of common variation, over 95% of the currently accessible variants found in any individual are present in this data set. On average, each person is found to carry approximately 250 to 300 loss-of-function variants in annotated genes and 50 to 100 variants previously implicated in inherited disorders. We demonstrate how these results can be used to inform association and functional studies. From the two trios, we directly estimate the rate of de novo germline base substitution mutations to be approximately 10(-8) per base pair per generation. We explore the data with regard to signatures of natural selection, and identify a marked reduction of genetic variation in the neighbourhood of genes, due to selection at linked sites. These methods and public data will support the next phase of human genetic research.Molecular Epidemiolog