The pathophysiology and development of immunity during long-term subclinical infection with Trichostrongylus colubriformis of sheep receiving different nutritional treatments

• Published in: Veterinary parasitology Vol. 65; no. 1; pp. 41 - 54
• Main Authors: Kyriazakis, I., Anderson, D.H., Coop, R.L., Jackson, F.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.10.1996
• Subjects: ABSORCION DE SUSTANCIAS NUTRITIVAS; ABSORPTION DE SUBSTANCES NUTRITIVES; Albumin; Animal Nutritional Physiological Phenomena; Animals; Anthelmintics - therapeutic use; Benzimidazoles - therapeutic use; CONTENIDO PROTEICO; Diet; Diet, Protein-Restricted; Dietary Proteins; DIETAS RESTRICTAS EN PROTEINAS; EXPERIMENTAL INFECTION; Feces - parasitology; Female; Food Preferences; Fructosamine; Fructosamine - blood; FUNCTIONAL DISORDERS; HOST PARASITE RELATIONS; IMMUNE RESPONSE; Immunity; INFECCION EXPERIMENTAL; INFECTION EXPERIMENTALE; Leukocyte Count; Levamisole - therapeutic use; Nematoda; NUTRIENT UPTAKE; OVIN; OVINOS; Parasite Egg Count; Phosphorus; Phosphorus - blood; PROTEIN CONTENT; Protein nutrition; PROTEIN RESTRICTED DIETS; Reference Values; REGIME ALLEGE EN PROTEINE; RELACIONES HUESPED PARASITO; RELATION HOTE PARASITE; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; Serum Albumin - metabolism; SHEEP; Sheep Diseases; TENEUR EN PROTEINES; TRASTORNOS FUNCIONALES; Trichostrongylosis - immunology; Trichostrongylosis - physiopathology; Trichostrongylosis - veterinary; TRICHOSTRONGYLUS COLUBRIFORMIS; TROUBLE FONCTIONNEL; Fructosamine; Protein nutrition; Diet; Albumin; Phosphorus; Sheep; Immunity; Nematoda; Trichostrongylus colubriformis
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/0304-4017(96)00947-8

The objective of this study was to investigate the relationship between protein nutrition, the pathophysiology, and acquisition and expression of immunity in long-term subclinical intestinal parasitism in sheep. Growing sheep were either uninfected controls or parasitised for 27 weeks with a daily dose of 2500 larvae of Trichostrongylus colubriformis, whilst they were given access to: (1) a low protein food, (2) a high protein food, or (3) a choice between the two foods, where they were allowed to select their diet. Blood samples were taken weekly for determination of serum albumin, total protein, Ca, P, urea and fructosamine concentrations. At the end of the study all sheep received a single (secondary) challenge infection (30 000 T. colubriformis L 3) after treatment with anthelmintic to assess their immune status. The concentrations of sheep-mast cell proteinases (SMCP) in intestinal tissue, the number of circulating eosinophils and the total worm numbers recovered from the intestinal tract were used to investigate the effects of previous nutrition on the acquisition and expression of immunity. From the biochemical variables measured over 27 weeks, only serum fructosamine was affected by the interaction between feeding treatment and parasitism: fructosamine concentrations declined only in the parasitised animals on the low protein food during Weeks 6–15 of infection. This casts doubt on the usefulness of plasma fructosamine levels as an indicator of gastrointestinal parasitism, due to its being influenced by the nutritional environment. Total protein, albumin, calcium and phosphorus concentrations in the serum were affected by parasitism, but independently of feeding treatment. During the period of secondary challenge eosinophil numbers and SMCP concentrations were higher in the parasitised animals, reflecting the animals immune responsiveness. The numbers of worms recovered from the intestine of previously parasitised sheep were low; all three indicators of the development of acquired immunity were unaffected by pathophysiology of long term subclinical intestinal parasitism and the expression of acquired immunity induced by a trickle infection could be affected by the feeding treatment of the sheep (protein nutrition).