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The effects of Diet and corticosteroid-induced immune suppression during infection by Haemonchus contortus in lambs
  • Universidade Estadual Paulista (UNESP)
  • Universidade de São Paulo (USP)
  • Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
  • Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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 82g 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 171g 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 (1.33mg/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.
Issue Date: 
Veterinary Parasitology, p. 1-6, 2015.
Time Duration: 
Elsevier B. V.
  • Immunity
  • Nutrition
  • Sheep
  • Worm control
Access Rights: 
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Appears in Collections:Artigos, TCCs, Teses e Dissertações da Unesp

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