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This Article Full Text (PDF) All Versions of this Article: jas.2008-1702v1 jas.2008-1702v2 87/7/2367    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bambou, J. C. Articles by González-García, E. Search for Related Content PubMed PubMed Citation Articles by Bambou, J. C. Articles by González-García, E.

Intake and digestibility of naïve kids differing in genetic resistance and experimentally parasitized (indoors) with Haemonchus contortus in two successive challenges

J. C. Bambou^*, R. Arquet, H. Archimède^*, G. Alexandre^*, N. Mandonnet^* and E. González-García^*

^* INRA UR143, Unité de Recherches Zootechniques, Centre INRA Antilles Guyane, Domaine Duclos, 97170 Petit Bourg, Guadeloupe (French West Indies) INRA, Domaine Gardel, 97129 Moule, Guadeloupe (French West Indies)

gonzaleg{at}supagro.inra.fr

Abstract

We evaluated the effects of infection with Haemonchus contortus on feed intake, digestibility, fecal egg count, circulating eosinophils, and packed cell volume in Creole kids differing in genetic resistance (susceptible, S; resistant, R) to gastrointestinal parasitism and maintained on a similar level of nutrition. The experiment was carried out during 2 periods of 6 wk each differing in immunity development stage. In the first period (‘acquisition of immunity’, Period I), 22 naïve male kids (23.4 ± 0.65 kg BW) were housed in individual boxes and fed a hay-based diet, and a primary infection was induced. In the second period (‘expression of immunity’, Period II), 15 of the initial 22 kids (28.4 ± 0.77 kg BW) were submitted to a secondary infection. Housing and management were uniform throughout the experiment. For each period, measurements of intake and digestibility were made at 0, 2, and 4 wk post-infection (WPI) with a single dose of 10,000 L₃. The DMI and total-tract DM, OM, CP, NDF, and ADF digestibilities were determined using the total feces collection and ad libitum forage supply method. Fecal and blood samples were collected weekly to measure fecal egg count, circulating eosinophils, and packed cell volume. Infection with Haemonchus contortus affected feed intake, basically during Period I. The absence of anorexia in Period II was probably due to the acquired immunity of kids. The DMI was affected (P = 0.05) by genetic predisposition to resistance (626 vs. 583 ± 26 g/d, for R vs. S) and WPI, being highest in the second WPI (693 vs. 614 and 657 g/d, for WPI-2 vs. WPI-0 and WPI-4, respectively). The latter was related to worm establishment phase and was linked to the lower total tract digestibilities at this point. Digestibilities were lowest at WPI-2. The fecal egg counts were higher (P < 0.001) in Period I than II, and differences between S and R were evident after the fifth WPI in Period II. Circulating eosinophils were greater (P < 0.001) in S vs. R. The results suggest that effects of these parasites on intake and digestibility are influenced by the individual genetic resistance and the immunological stage, and the strongest impact occurs between the second and the third WPI, a period during which the immune response is more pronounced, probably due to parasite maturation.

Key Words: digestibility • goat • Haemonchus • immunity • intake • resistance