Christelle Knudsen1, Sylvie Combes1, Christophe Briens2, Joël Duperray3, Gwenaël Rebours4, Jean-Marc Salaun5, Angélique Travel6, Delphine Weissman7, Thierry Gidenne8, Isabelle P Oswald9. 1. INRA (Institut National de la Recherche Agronomique), GenPhySE (Génétique, Physiologie et Systèmes d'Elevage), Castanet-Tolosan, France; Université de Toulouse, INP (Institut National Polytechnique), ENSAT (Ecole Nationale Supérieure Agronomique de Toulouse), GenPhySE (Génétique, Physiologie et Systèmes d'Elevage), Castanet-Tolosan, France; Université de Toulouse, INP, ENVT, GenPhySE (Génétique, Physiologie et Systèmes d'Elevage), Toulouse, France; 2. CCPA, Janzé, France; 3. Evialis, Vannes, France; 4. TECHNA, Coueron, France; 5. Sanders, Bruz, France; 6. ITAVI, UMT BIRD (Unité Mixte Technologique Biologie et Innovation pour la Recherche et le Développement en aviculture), Centre INRA de Tours, Nouzilly, France; 7. INZO, Chierry, France; 8. INRA (Institut National de la Recherche Agronomique), GenPhySE (Génétique, Physiologie et Systèmes d'Elevage), Castanet-Tolosan, France; Université de Toulouse, INP (Institut National Polytechnique), ENSAT (Ecole Nationale Supérieure Agronomique de Toulouse), GenPhySE (Génétique, Physiologie et Systèmes d'Elevage), Castanet-Tolosan, France; Université de Toulouse, INP, ENVT, GenPhySE (Génétique, Physiologie et Systèmes d'Elevage), Toulouse, France; thierry.gidenne@toulouse.inra.fr. 9. INRA, UMR 1331, Toxalim, Toulouse, France; and Université de Toulouse, INP, UMR 1331, Toxalim, Toulouse, France.
Abstract
BACKGROUND: Short-term feed restriction strategies are used in rabbits to reduce postweaning digestive disorders, but little is known about the involvement of the immune system in these beneficial effects. OBJECTIVE: In the present study, the consequences of feed and energy restriction on immune response were investigated. METHODS: At weaning, 320 male and female rabbits were assigned to 4 groups differing in dietary digestible energy (DE) concentrations and intake levels: a low-energy ad libitum-feed (LE100) group, a low-energy restricted-feed (LE75) group, a high-energy ad libitum-feed (HE100) group, and a high-energy restricted-feed (HE75) group. The high-energy groups consumed 10.13 MJ DE/kg of feed, whereas the low-energy groups consumed 9.08 MJ DE/kg (formulated values). Intake amounts for the restricted groups were 75% those of the ad libitum groups. Rabbits consumed these diets until age 63 d, after which they consumed feed ad libitum for 9 d. Ten rabbits per group and per age were killed at ages 42, 50, 63, and 72 d. Spleens and appendixes were weighed; Peyer's patch surface area was determined by image analysis; plasma total immunoglobulin (Ig) G and anti-ovalbumin IgG; and fecal and plasma IgA concentrations were determined by ELISA; and ileal expressions of cytokines were measured by quantitative reverse transcriptase-polymerase chain reaction at ages 50 and 63 d. RESULTS: The relative weight and size of the lymphoid organs were not affected by treatments. Concentrations of plasma total IgA (-41% at 63 d and -29% at 72 d), IgG (-22% at 72 d), and anti-ovalbumin IgG (-41% at 63 d) were lower with feed restriction. Fecal IgA concentrations were lower with quantitative restriction (-40%, -52%, and -65% at age 42, 50, and 63 d, respectively) and energy restriction (-56%, -46%, and -73% at ages 50, 63, and 72 d, respectively). Feed-restricted rabbits tended to have greater expressions of interleukin (IL) 1β and IL-2 and lower expressions of tumor necrosis factor α (P < 0.1). CONCLUSION: These results demonstrated that, in rabbits, restriction and, to a lesser extent, dietary energy concentration modulate gut immunity.
BACKGROUND: Short-term feed restriction strategies are used in rabbits to reduce postweaning digestive disorders, but little is known about the involvement of the immune system in these beneficial effects. OBJECTIVE: In the present study, the consequences of feed and energy restriction on immune response were investigated. METHODS: At weaning, 320 male and female rabbits were assigned to 4 groups differing in dietary digestible energy (DE) concentrations and intake levels: a low-energy ad libitum-feed (LE100) group, a low-energy restricted-feed (LE75) group, a high-energy ad libitum-feed (HE100) group, and a high-energy restricted-feed (HE75) group. The high-energy groups consumed 10.13 MJ DE/kg of feed, whereas the low-energy groups consumed 9.08 MJ DE/kg (formulated values). Intake amounts for the restricted groups were 75% those of the ad libitum groups. Rabbits consumed these diets until age 63 d, after which they consumed feed ad libitum for 9 d. Ten rabbits per group and per age were killed at ages 42, 50, 63, and 72 d. Spleens and appendixes were weighed; Peyer's patch surface area was determined by image analysis; plasma total immunoglobulin (Ig) G and anti-ovalbumin IgG; and fecal and plasma IgA concentrations were determined by ELISA; and ileal expressions of cytokines were measured by quantitative reverse transcriptase-polymerase chain reaction at ages 50 and 63 d. RESULTS: The relative weight and size of the lymphoid organs were not affected by treatments. Concentrations of plasma total IgA (-41% at 63 d and -29% at 72 d), IgG (-22% at 72 d), and anti-ovalbumin IgG (-41% at 63 d) were lower with feed restriction. Fecal IgA concentrations were lower with quantitative restriction (-40%, -52%, and -65% at age 42, 50, and 63 d, respectively) and energy restriction (-56%, -46%, and -73% at ages 50, 63, and 72 d, respectively). Feed-restricted rabbits tended to have greater expressions of interleukin (IL) 1β and IL-2 and lower expressions of tumor necrosis factor α (P < 0.1). CONCLUSION: These results demonstrated that, in rabbits, restriction and, to a lesser extent, dietary energy concentration modulate gut immunity.