Chickens exhibit varied responses to infection with Eimeria parasites. We hypothesise that broilers selected for increased growth rate will show lower resistance and tolerance to a coccidian challenge. 288 chickens of fast (F) or slow (S) growing lines were inoculated with 0 (control), 2500 (low-dose), or 7000 (high-dose) sporulated E. maxima oocysts at 13 days of age in two consecutive rounds. Gain and Intake were measured daily and their values relative to BW at the point of infection were calculated over the pre-patent (days 1-4 post-infection), acute (d5-8 pi), and recovery (d9-12 pi) phases of infection to assess the impact of infection. Levels of plasma carotenoids, vitamins E and A, long bone mineralisation, caecal microbiota diversity indices, and histological measurements were assessed at the acute (d6 pi) and recovery stage (d13 pi). In addition, we measured the levels of nitric oxide metabolites and the number of parasite genome copies in the jejunumat d6pi. In absolute terms F birds grew 1.42 times faster than S birds when not infected. Infection significantly reduced relative daily gain and intake (P < 0.001), with the effects being most pronounced during the acute phase (P < 0.001). Levels of all metabolites were significantly decreased, apart from NO which increased (P < 0.001) in response to infection on d6pi, and were accompanied by changes in histomorphometric features and the presence of E. maxima genome copies in infected birds, which persisted to d13pi. Furthermore, infection reduced tibia and femur mineralisation, which also persisted to d13pi. Reductions in measured variables were mostly independent of dose size, as was the level of parasite replication. The impact of infection was similar for S and F-line birds for all measured parameters, and there were no significant interactions between line x dose size on any of these parameters. In conclusion, our results suggest that line differences in productive performance do not influence host responses to coccidiosis when offered nutrient adequate diets.

• Klíčová slova
• Bone mineralisation, Broiler, Coccidiosis, Eimeria maxima, Genetic selection, Growth rate, Resistance, Tolerance,
• MeSH
• Eimeria genetika   izolace a purifikace   fyziologie   MeSH
• fyziologická kalcifikace MeSH
• fyziologie výživy zvířat MeSH
• jejunum parazitologie   MeSH
• karotenoidy krev   MeSH
• kokcidióza parazitologie   veterinární   MeSH
• krmivo pro zvířata analýza   MeSH
• kur domácí růst a vývoj   parazitologie   fyziologie   MeSH
• nemoci drůbeže parazitologie   patofyziologie   MeSH
• oxid dusnatý krev   MeSH
• potravní doplňky MeSH
• vitamin A krev   MeSH
• vitamin E krev   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• karotenoidy MeSH
• oxid dusnatý MeSH
• vitamin A MeSH
• vitamin E MeSH