lactoferrin and Poultry-Diseases

Antibiotics are commonly used in poultry feed as growth promoters. This practice is questioned given the arising importance of antibiotic resistance. Antimicrobial peptides can be used as food additives for a potent alternative to synthetic or semi-synthetic antibiotics. The objective of this study was to develop a peptide production method based on membrane adsorption chromatography in order to produce extracts with antimicrobial activity against avian pathogens (Salmonella enterica var. Enteritidis, Salmonella enterica var. Typhimurium, and two Escherichia coli strains, O78:H80 and TK3 O1:K1) as well as Staphylococcus aureus. To achieve this, buttermilk powder and purified lactoferrin were digested with pepsin. The peptide extracts (<10 kDa) were fractionated depending on their charges through high-capacity cation-exchange and anion-exchange adsorptive membranes. The yields of cationic peptide extracts were 6·3 and 15·4% from buttermilk and lactoferrin total peptide extracts, respectively. Antimicrobial activity was assessed using the microdilution technique on microplates. Our results indicate that the buttermilk cationic peptide extracts were bactericidal at less than 5 mg/ml against the selected avian strains, with losses of 1·7 log CFU/ml (Salm. Typhimurium) to 3 log CFU/ml (E. coli O78:H80); viability decreased by 1·5 log CFU/ml for Staph. aureus, a Gram-positive bacterium. Anionic and non-adsorbed peptide extracts were inactive at 5 mg/ml. These results demonstrate that membrane adsorption chromatography is an effective way to prepare a cationic peptide extract from buttermilk that is active against avian pathogens.

Topics: Animals; Anti-Infective Agents; Buttermilk; Escherichia coli; Lactoferrin; Pepsin A; Peptides; Poultry; Poultry Diseases; Salmonella enterica; Staphylococcus aureus

Avian pathogenic Escherichia coli (APEC) causes respiratory and systemic disease in poultry. Sequencing of a multilocus sequence type 95 (ST95) serogroup O1 strain previously indicated that APEC resembles E. coli causing extraintestinal human diseases. We sequenced the genomes of two strains of another dominant APEC lineage (ST23 serogroup O78 strains χ7122 and IMT2125) and compared them to each other and to the reannotated APEC O1 sequence. For comparison, we also sequenced a human enterotoxigenic E. coli (ETEC) strain of the same ST23 serogroup O78 lineage. Phylogenetic analysis indicated that the APEC O78 strains were more closely related to human ST23 ETEC than to APEC O1, indicating that separation of pathotypes on the basis of their extraintestinal or diarrheagenic nature is not supported by their phylogeny. The accessory genome of APEC ST23 strains exhibited limited conservation of APEC O1 genomic islands and a distinct repertoire of virulence-associated loci. In light of this diversity, we surveyed the phenotype of 2,185 signature-tagged transposon mutants of χ7122 following intra-air sac inoculation of turkeys. This procedure identified novel APEC ST23 genes that play strain- and tissue-specific roles during infection. For example, genes mediating group 4 capsule synthesis were required for the virulence of χ7122 and were conserved in IMT2125 but absent from APEC O1. Our data reveal the genetic diversity of E. coli strains adapted to cause the same avian disease and indicate that the core genome of the ST23 lineage serves as a chassis for the evolution of E. coli strains adapted to cause avian or human disease via acquisition of distinct virulence genes.

Topics: Animals; Biological Evolution; DNA, Bacterial; Escherichia coli; Fimbriae Proteins; Gene Expression Regulation, Bacterial; Genome, Bacterial; Lactoferrin; Leukocyte Disorders; Molecular Sequence Annotation; Molecular Sequence Data; Mutation; Phylogeny; Poultry Diseases; Turkeys; Virulence

The purpose of this study was to investigate the effects of dietary supplementation with recombinant porcine lactoferrin (rPLF) produced by yeast culture on peripheral lymphocyte proliferation and serum antibody titers in chickens vaccinated against the infectious bursal disease (IBD) virus. Treatment groups were fed with rPLF powder in their diet (2.0%, w/w), and the IBD vaccine was administrated at 1 and 3 weeks of age. At 8, 12, and 16 weeks after vaccination, serum IBD antibody titers were measured via the micro-method and T cell proliferation rates were evaluated. In gene expression analyses, rPLF-treated chicken peripheral T lymphocytes were stimulated with concanavalin A (ConA) for 24h. The mRNA expression levels of interleukin-2 (IL-2), interferon-gamma (IFN-gamma), interleukin-4 (IL-4), and interleukin-12 (IL-12) were determined using a semi-quantitative RT-PCR assay. The results revealed that the rPLF additive led to significant increases in serum IgG and IBD-specific antibody titers (P<0.05). The rPLF administration significantly increased chicken intestinal villous lengths and also enhanced the expression of IFN-gamma and IL-12 in chicken T lymphocytes. These data suggest that rPLF enhances cell-mediated immunity and augment the ability of IBD vaccination to benefit chicken industry in disease resistance.

Topics: Adjuvants, Immunologic; Administration, Oral; Animals; Birnaviridae Infections; Cell Proliferation; Cells, Cultured; Chickens; Cytokines; Gene Expression Profiling; Infectious bursal disease virus; Lactoferrin; Lymphocytes; Poultry Diseases; Recombinant Proteins; Vaccination; Viral Vaccines