Relationship of intestinal histology with the resistance to Trichostrongylus colubriformis infection in three breeds of sheep1

Amarante A.F.T., Rocha R.A. & Bricarello P.A. 2006. Relationship of intestinal histology with the resistance to Trichostrongylus colubriformis infection in three breeds of sheep. Pesquisa Veterinária Brasileira 26(1):43-48. Departamento de Parasitologia, Instituto de Biociências, Universidade Estadual Paulista (Unesp), Cx. Postal 510, Botucatu, SP 18618-000, Brazil. E-mail: [email protected] The study was carried out to evaluate the relationship of inflammatory intestinal cells with the resistance to Trichostrongylus colubriformis infections in three breeds of sheep (Santa Ines, Suffolk and Ile de France), naturally infected. Mast cells, eosinophils, and globule leucocytes were enumerated in intestinal mucosa. Histamine concentration was estimated in intestinal tissue samples and the length of male and female specimens were determined. The three breeds of sheep showed similar cellular response in the small intestine mucosa (P>0.05). There was extensive variation among sheep in the parasitological and inflammatory cell variables, even in lambs of the same breed. In general, animals presenting less inflammatory cells had a larger worm burden, higher fecal egg counts, and larger T. colubriformis worms. The inflammatory cells possibly impaired the parasite’s establishment, development, and survival.