Fokus på robusthed i økologisk slagtekyllingeproduktion

Naturlig modstandskraft er vigtig i fremtidens økologiske produktionssystemer for at opfylde markedets krav og forbedre den overordnede produktivitet. Men udviklingen af et robust immunsystem vil sandsynligvis være på bekostning af andre funktioner såsom vækst og reproduktion. I Organic RDD projektet SUMMER har man undersøgt tarmsundhed og immunsystem hos forskellige afstamninger af slagtekyllinger med forskellige vækstpotentialer Deimmunologiske undersøgelser viser, at der er forskel på de basale immunfunktioner mellem afstamningerne. Den afstamning med det laveste vækstpotentiale SU51 ser ud til at have et mere robust immunsystem end den afstamning med det største potentiale JA757

Social Rank Influences the Distribution of Blood Leukocyte Subsets in Female Growing Pigs

The effect of high (DOM) and low (SUB) social rank on blood immune variables was examined in female  growing pigs. Pigs were mixed with unfamiliar pigs at 9 weeks of age and kept in stable groups of 4 pigs for  5 weeks. Social rank was determined using a feeding competition test. SUB pigs showed reduced growth  as compared to DOM pigs confirming their lower social status. Blood was sampled for immunological assessments  immediately before grouping the pigs and again after the 5 weeks of social housing. White Blood  Cell (WBC) counts, percentage of CD4 positive cells (CD4+), percentage of CD8 positive cells (CD8+), percentage  of swine leukocyte antigen II (SLAII) carrying cells, LPS-stimulated Toll-like Receptor 4 (TLR4)  expression, and LPS-stimulated tumor necrosis factor-alpha (TNF-) responsiveness were determined at  both times. IgG and IgM concentrations were measured following the 5 weeks of social housing only.  From the WBC counts it was found that the percentage of neutrophils was higher in SUB pigs and the neutrophil  to lymphocyte ratio was higher in DOM pigs. The percentage of CD4+ cells decreased with time in  both DOM and SUB pigs, but only significantly in SUB pigs. The percentage of CD8+ cells was higher in  SUB pigs than in DOM pigs and decreased with time in both DOM and SUB pigs. In addition, SUB pigs  had a higher ex vivo TNF- responsiveness as compared to DOM pigs. Both the percentage of SLAII carrying  cells and LPS-stimulated TLR4 expression increased with time, but here no significant effect of social  rank was found. In addition, neither IgG nor IgM concentrations showed any relationship with social rank.  The findings indicate that social rank influences the distribution of blood leukocyte subsets in female growing  pigs, suggesting that the pig would be a good model for investigating the effects of long-term immunomodulation  on health.

Correlation in chicken between the marker LEI0258 alleles and Major Histocompatibility Complex sequences

<p>Abstract</p> <p>Background</p> <p>The LEI0258 marker is located within the B region of the chicken Major Histocompatibility Complex (MHC), and is surprisingly well associated with serology. Therefore, the correlation between the LEI0258 alleles and the MHC class I and the class II alleles at the level of sequences is worth investigating in chickens. Here we describe to which extent the LEI0258 alleles are associated with alleles of classical class I genes and non-classical class II genes, in reference animals as well as local breeds with unknown MHC haplotypes.</p> <p>Methods</p> <p>For the class I region, in an exploratory project, we studied 10 animals from 3 breeds: Rhode Island Red, White Leghorn and Fayoumi chickens, by cloning and sequencing <it>B-F1</it> and <it>B-F2</it> cDNA from exon 1 to 3’UTR. For the class II region, we reconstructed haplotypes of the 8.8 kb genomic region encompassing three non-classical class II genes: <it>B-DMA</it>, <it>B-DMB1</it> and <it>B-DMB2</it>, for 146 animals from more than 50 breeds including wild species of jungle fowls.</p> <p>Results</p> <p>Overall we found that the LEI0258 marker genotypes gave good indications of the MHC haplotypes, and a very good predictions (>0.95) of the heterozygosity of an animal at the MHC locus.</p> <p>Conclusions</p> <p>Our results show that the LEI0258 alleles are strongly associated with haplotypes of classical class I genes and non-classical class II genes, unravelling the reasons why this marker is becoming the reference marker for MHC genotyping in chickens.</p

Development of an oral tolerance model in rats for investigation of bioactive food components

In a recent study on rats, complete diets produced from three cultivation systems were compared on a range of health biomarkers, and notable differences appeared with regard to IgG levels(1). In order to chase this result, the objective of the present study was to develop an oral tolerance model in rats for comparison of diets composed of ingredients from different organic and conventional cultivation systems with regard to immunological responses