Long-Term Effects of Early Low-Phosphorous Nutritional Conditioning on Broiler Chicken Performance, Bone Mineralization, and Gut Health Under Adequate or Phosphorous-Deficient Diets.

Phosphorous is essential for many metabolic functions and the constitution of bones. Poultry have limited ability to use phosphorous from diets, which is mainly excreted and causes environmental concern. For this reason, diets are commonly supplemented with inorganic phosphorus and phytases.

Heterogeneity of Moraxella isolates found in the nasal cavities of piglets.

Background: Previous studies have shown that the genus Moraxella is commonly present in the nasal microbiota of swine.

Results: In this study, 51 isolates of Moraxella were obtained from nasal swabs from 3 to 4 week old piglets, which represented 26 different fingerprintings by enterobacterial repetitive intergenic consensus (ERIC)-PCR. Whole 16S rRNA gene sequencing allowed the identification at species level of the Moraxella spp.

Changes in bacterial population of gastrointestinal tract of weaned pigs fed with different additives.

This study aimed to provide novel insights into the gastrointestinal microbial diversity from different gastrointestinal locations in weaning piglets using PCR-restriction fragment length polymorphism (PCR-RFLP). Additionally, the effect of different feed additives was analyzed. Thirty-two piglets were fed with four different diets: a control group and three enriched diets, with avilamycin, sodium butyrate, and a plant extract mixture.

Effect of marbofloxacin on Haemophilus parasuis nasal carriage.

Haemophilus parasuis is a colonizer of the upper respiratory tract and the causative agent of Glässer's disease in swine. This study focused on the nasal carriage of H. parasuis after treatment with marbofloxacin.

Development of a genetic manipulation system for Haemophilus parasuis.

Haemophilus parasuis is a member of the family Pasteurellaceae and an important respiratory-tract pathogen of swine, which is the etiological agent of Glasser's disease. Because no genetic manipulation system is available for H. parasuis so far, in vivo studies about the role of its genes involved in virulence are unfeasible.

Pasteurella multocida contains multiple immunogenic haemin- and haemoglobin-binding proteins.

Iron-dependent outer membrane proteins (IROMPs) play an important role in bacterial pathogenesis and present several attributes of potential vaccine candidates. TBLASTN analysis of the Pasteurella multocida Pm70 genome using the same molecules of other bacterial pathogens as a query identified eight putative haemin and haemoglobin receptors for this organism. Quantitative binding assays have demonstrated that the proteins PM0040, PM0236, PM0741, PM1081, PM1428, PM0592 and HgbA bind both haemin and haemoglobin, whereas PM0576 and PM1282 ORFs only bind either haemoglobin or haemin, respectively.

fur-independent regulation of the Pasteurella multocida hbpA gene encoding a haemin-binding protein.

Treatment of bacterial cultures with chelating agents such as 2,2'-dipyridyl (DPD) induces expression of iron-regulated genes. It is known that in the gamma-Proteobacteria, the Fur protein is the major regulator of genes encoding haem- or haemoglobin-binding proteins. Electrophoretic analysis of outer-membrane proteins of the gamma-proteobacterium Pasteurella multocida has revealed the induction of two proteins of 60 and 40 kDa in DPD-treated cultures in both wild-type and fur-defective strains.

The high-affinity zinc-uptake system znuACB is under control of the iron-uptake regulator (fur) gene in the animal pathogen Pasteurella multocida.

The Pasteurella multocida znuACB genes encoding a high-affinity zinc-uptake system have been identified and cloned. In contrast to what happens in Escherichia coli, znuA is not physically linked to znuCB. Through lacZ transcriptional fusions it has been demonstrated that zinc negatively regulates both znuA and znuCB operons.

Characterization of the Pasteurella multocida hgbA gene encoding a hemoglobin-binding protein.

Reverse transcriptase PCR analyses have demonstrated that open reading frames (ORFs) PM0298, PM0299, and PM0300 of the animal pathogen Pasteurella multocida constitute a single transcriptional unit. By cloning and overexpression studies in Escherichia coli cells, the product of ORF PM0300 was shown to bind hemoglobin in vitro; this ORF was therefore designated hgbA. In vitro and in vivo quantitative assays demonstrated that the P.

Role of the high-affinity zinc uptake znuABC system in Salmonella enterica serovar typhimurium virulence.

The Salmonella enterica serovar Typhimurium znuABC genes encoding a high-affinity zinc uptake system and its regulatory zur gene have been cloned. Salmonella serovar Typhimurium zur and znuC knockout mutants have been constructed by marker exchange. The 50% lethal dose of the znuC mutant increased when either orally or intraperitoneally inoculated in BALB/c mice, while virulence of the zur mutant decreased only when mice were intraperitoneally challenged.

Pasteurella multocida exbB, exbD and tonB genes are physically linked but independently transcribed.

The exbB, exbD and tonB genes of the Pasteurella multocida animal pathogen have been cloned by complementation of an Escherichia coli tonB mutant. Despite these three genes being physically linked, RT-PCR analysis, lacZ transcriptional fusions and construction of insertional mutants have demonstrated that they do not constitute an operon, but rather are transcribed independently from each other. Furthermore, expression of these three genes is under iron control as revealed by lacZ fusions and Fur titration assay analysis.

Intracellular cyclic AMP concentration is decreased in Salmonella typhimurium fur mutants.

It is known that the Fur protein negatively regulates iron-uptake systems in different bacterial species, including Salmonella typhimurium. In this study it has been shown that the intracellular concentration of cyclic AMP (cAMP) is lower in a knockout S. typhimurium fur mutant than in the wild-type strain.