The chicken insulin-like growth factor (IGF)1 and IGF2 genes have been partially sequenced in six individuals of each of two chicken strains of the Black Penedesenca breed (PN and MN). These two strains are genetically diverse for growth traits. Sequence alignment revealed the existence of three single nucleotide polymorphisms (SNP) (IGF1-SNP1, IGF2-SNP2, and IGF2-SNP3). These three SNP and a fourth IGF1 polymorphism (IGF1-SNP4) were typed in 60 individuals from each strain by using PCR-RFLP or primer extension analysis. No significant associations among these four SNP, growth traits, and plasma IGF1 concentration were identified. In contrast, suggestive associations (P < or = 0.05) were found between IGF1-SNP1 and average daily gain at 107 d and feed efficiency at 44, 73, and 107 d. However, these associations were not simultaneously found in both strains suggesting that they might have been produced by linkage disequilibrium with another mutation located in the IGF1 locus or another linked gene. Since the PN and MN strains differ very markedly on their feed intake, the chicken leptin gene was included in the sequence analysis. Unfortunately, attempts to amplify several regions of this gene were unsuccessful. Even when primers complementary to highly conserved regions were used, the PCR consistently failed. Other authors have reported similar problems when trying to amplify avian leptin sequences.

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bMycobacterium tuberculosis complex, Mycobacterium avium, and many other nontuberculous mycobacteria are worldwide distributed microorganisms of major medical and veterinary importance. Considering the growing epidemiologic significance of wildlife-livestock-human interrelation, developing rapid detection tools of high specificity and sensitivity is vital to assess their presence and accelerate the process of diagnosing mycobacteriosis. Here we describe the development and evaluation of a novel tetraplex real-time PCR for simultaneous detection of Mycobacterium genus, M. avium subspecies, and M. tuberculosis complex in an internally monitored single assay. The method was evaluated using DNA from mycobacterial (n ‫؍‬ 38) and nonmycobacterial (n ‫؍‬ 28) strains, tissues spiked with different CFU amounts of three mycobacterial species (n ‫؍‬ 57), archival clinical samples (n ‫؍‬ 233), and strains isolated from various hosts (n ‫؍‬ 147). The minimum detectable DNA amount per reaction was 50 fg for M. bovis BCG and M. kansasii and 5 fg for M. avium subsp. hominissuis. When spiked samples were analyzed, the method consistently detected as few as 100 to 1,000 mycobacterial CFU per gram. The sensitivity and specificity values for the panel of clinical samples were 97.5 and 100% using a verified culture-based method as the reference method. The assays performed on clinical isolates confirmed these results. This PCR was able to identify M. avium and M. tuberculosis complex in the same sample in one reaction. In conclusion, the tetraplex real-time PCR we designed represents a highly specific and sensitive tool for the detection and identification of mycobacteria in routine laboratory diagnosis with potential additional uses. T he genusMycobacterium encompasses a large number of worldwide distributed pathogenic and opportunistic bacteria responsible for a broad range of infectious diseases. Mycobacterium tuberculosis complex, Mycobacterium avium, and many other nontuberculous mycobacteria (NTM) are of major medical and veterinary significance. Human tuberculosis (TB) due to infection with members of M. tuberculosis complex, especially with M. tuberculosis, remains an important health problem according to annual reports of the World Health Organization (WHO). Animal or bovine TB (bTB), caused primarily by Mycobacterium bovis but also by Mycobacterium caprae, poses serious socioeconomic and health threats (1) and is a notifiable disease listed under the World Organization for Animal Health (OIE) Terrestrial Animal Health Code (TAHC). Although bTB is controlled in most developed countries, its eradication has not been fully accomplished due to a lack of sensitivity of diagnostic tools and to the persistence of infection in extensive farming and wild populations (2). The disease remains a significant problem in many countries with less developed laboratory capacity (1). Accordingly, human TB caused by M. bovis or M. caprae is supposed to be infrequent in developed regions but is relatively common and possibly underestimated in ...

BackgroundParatuberculosis vaccination has been in use in some regions for many decades, but results have not been widely spread. A new Mycobacterium avium subsp. paratuberculosis (MAP) killed vaccine was studied in relationship with its effects on fecal shedding and milk production in four farms while other two were kept as controls submitted to a test and cull scheme.FindingsFecal detection (n = 1829) and milking records (n = 2413) have been analyzed after two (5 herds) and four (1 herd) years of the beginning of the intervention. Shedder prevalence was reduced by 100% in three of the four vaccinated farms, 68% in the total of vaccinated animals and 46% in the two control farms. Total amount of MAP shed was reduced 77% in the vaccinated farms and 94% in the control farms. Overall milk production increased up to 3.9% after vaccination, while there was no significant difference in production after intervention in the non-vaccinated farms.ConclusionMAP shedding reduction can be quickly accomplished both by vaccination and by testing and culling. However, vaccination appears to be a less expensive and more sustainable strategy since it required one single intervention and was also associated with an increase in milk production.