Characterisation of the porcine cytokines which activate the CD131ßc common sub-unit, for potential immune-augmentation.

Early acting cytokines and growth factors such as those of the CD131 ßc subunit, may offer an alternative method to the current use of antibiotics and chemicals such as anthelmintics in maintaining Porcine (Po) health. Thus far, the recombinant Po (rPo) Granulocyte-macrophage colony-stimulating factor (GM-CSF), rPo interleukin-3 (IL-3) and rPo interleukin-5 (IL-5) proteins have been identified and cloned and the biological activity of each cytokine has been confirmed in vitro, however, in vivo immune system regulation and hematopoietic stem cell (HSC) augmentation are regulated by numerous cytokines and cellular signals within the bone marrow (BM) niche. In order to quantify the use of recombinant cytokines in augmenting the immune response, it is necessary to determine the stages of hematopoiesis induced by each cytokine and possible areas of synergy requiring further investigation. Here we used the chemotherapeutic agent 5-fluorouracil (5-FU), to chemically induce a state of myelosuppression in young pigs. This allowed for the monitoring of both the autologous BM reconstitution and recombinant cytokine induced BM repopulation, precursor cell proliferation and cellular differentiation. The recombinant cytokines PoGM-CSF, PoIL-3 and PoIL-5 were administered by intramuscular injections (i.m.) following confirmation of 5-FU induced leukocytopenia. Blood and BM samples were collected and then analysed for cell composition. Statistically significant results were observed in several blood cell populations including eosinophils for animals treated with rPoIL-5, rPoGM-CSF and basophils for animals treated with rPoIL-3. BM analysis of CD90+ and CD172a+ cells confirmed myelosuppression in week one with significant results observed between rPoIL-3 and the 5-FU control group in week two and for the rPoGM-CSF group in week three. These results have demonstrated the effects of each of these rPo cytokines within the hematopoietic processes of the pig and may demonstrate similar outcomes in other mammalian models including human.

The effects of lactoferrin on the intestinal environment of broiler chickens.

The influence of in-feed lactoferrin (Lf) on bird production, intestinal microbiota, mucosal immune system and gut microarchitecture was assessed in male Cobb 500 broiler chickens. Birds were given one of four diets from day of hatch: Control (basal diet with no additives), ZnB (basal diet + 50 mg/kg zinc bacitracin), Lf 250 mg/kg (basal diet + 250 mg/kg Lf) and Lf 500 mg/kg (basal diet + 500 mg/kg Lf); n = 24 birds/treatment. An apparent metabolisable energy study was performed between d 25-32. Lf did not affect growth rate or feed conversion in the period 0-21 d of age, nor performance or energy metabolism during the 7 d metabolism experiment which commenced at 25 d of age.The profiles of caecal microbial communities were significantly different in birds given ZnB compared with birds given a diet with no additives, or supplemented with 250 mg/kg Lf. Birds given 250 mg/kg Lf also had a different microbial profile compared with birds given 500 mg/kg Lf. In comparison to control birds, Lf treated birds showed some differences in the T cell proportions in caecal tonsil and spleen. No differences in ileal villus height, crypt depth or goblet cell proportions were observed amongst dietary treatments. Whilst Lf had little effect on the measured parameters, the use of an integrated approach to study the influence of novel feed additives may facilitate a greater understanding of the relationships between nutrition, gut health and bird performance.