title: The effects of diet and corticosteroid-induced immune suppression during infection by Haemonchus contortus in lambs.
abstract: To evaluate the effects of Diet and corticosteroid-induced immune suppression during infection by Haemonchus contortus, 28 lambs were allocated to one of four groups treated as follows: Group Basal Diet - Normal; Group Basal Diet - Immune-Suppressed; Group Supplemented Diet - Normal; and Group Supplemented Diet - Immune-Suppressed. The Basal Diet contained Cynodon dactylon (cv. coast cross) hay with 82 g crude protein (CP)/kg dry matter (DM), which was provided to the lambs in all groups ad libitum. In addition, animals on the Supplemented Diet received daily a commercial concentrate containing 171 g CP/kg DM, which was offered in an amount corresponding to 3% of the animal's live weight. The Immune-Suppressed groups received treatments with the glucocorticoid methylprednisolone sodium succinate (1.33 mg/kg of body weight), administered weekly. All lambs received a single infection with 4000 H. contortus infective larvae (L3) and were euthanised 28 days post-infection. Differences in pH and in the short-chain fatty acid (SCFA) concentrations occurred in rumen as a result of the distinct Diets offered to lambs. Such changes, however, did not have any apparent effect on larvae exsheathment and/or larvae survival inside the rumen, with all groups presenting similar worm burdens. However, animals on the Supplemented Diet presented reductions in worm growth and faecal egg counts. There was a significant effect of the Diet on the IgG levels against total antigens of H. contortus L3 from 7 to 27 days post-infection, with supplemented animals showing higher overall mean values (P<0.05). The immunosuppressive treatments had no effect on worm burden despite the reduction in the numbers of inflammatory cells in the abomasal mucosa of the Immune-Suppressed groups. These groups showed longer worms and females with more eggs in comparison with their counterparts fed each Diet; however, only the length of males was significantly affected (P<0.05). In conclusion, the changes caused in the rumen contents by supplementation with concentrate did not impair H. contortus establishment.
authors.affiliation: UNESP - Universidade Estadual Paulista, Departamento de Parasitologia, Instituto de Biociências, Caixa Postal 510, CEP 18618-000 Botucatu, SP, Brazil.
authors.forename: Nadino
authors.initials: N
authors.lastname: Carvalho
authors.affiliation: UNESP - Universidade Estadual Paulista, Departamento de Parasitologia, Instituto de Biociências, Caixa Postal 510, CEP 18618-000 Botucatu, SP, Brazil.
authors.forename: José Henrique
authors.initials: JH
authors.lastname: das Neves
authors.affiliation: USP - Universidade de São Paulo, Centro de Energia Nuclear na Agricultura, Caixa Postal 96, CEP 13400-970 Piracicaba, SP, Brazil.
authors.forename: Carina
authors.initials: C
authors.lastname: Nazato
authors.affiliation: USP - Universidade de São Paulo, Centro de Energia Nuclear na Agricultura, Caixa Postal 96, CEP 13400-970 Piracicaba, SP, Brazil.
authors.forename: Helder
authors.initials: H
authors.lastname: Louvandini
authors.affiliation: UNESP - Universidade Estadual Paulista, Departamento de Parasitologia, Instituto de Biociências, Caixa Postal 510, CEP 18618-000 Botucatu, SP, Brazil. Electronic address: amarante@ibb.unesp.br.
authors.forename: Alessandro F T
authors.initials: AF
authors.lastname: Amarante
mesh_terms: D000818:Animals; D004032:Diet / Q000662:veterinary*; D005260:Female; D006188:Haemonchiasis / Q000276:immunology / Q000662:veterinary*; D006189:Haemonchus / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D007165:Immunosuppression Therapy / Q000662:veterinary*; D008297:Male; D008776:Methylprednisolone Hemisuccinate / Q000494:pharmacology*; D010270:Parasite Egg Count; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology*
chemical_list: D007074:Immunoglobulin G; D008776:Methylprednisolone Hemisuccinate
keywords: Immunity; Nutrition; Sheep; Worm control