Toggle Main Menu Toggle Search

Open Access padlockePrints

Starving for nutrients: anorexia during infection with parasites in broilers is affected by diet composition

Lookup NU author(s): Dr James Taylor, Dr Panagiotis Sakkas, Professor Ilias Kyriazakis



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2021 The Authors. In 2 experiments, we investigated whether diet composition plays a role in pathogen-induced anorexia, the voluntary reduction in ADFI during infection in broilers. We hypothesized that either energy or CP dietary content could influence the extent of anorexia in Ross 308 broilers and infection outcomes with Eimeria maxima. From d 13 of age, half of the birds were infected, and half were uninfected. ADFI was measured daily, and BW every 3 d until d 29. Oocyst excretion was measured daily from d 17 to 23. The impact of parasitism on the small intestine was assessed on d 19 and 25. In Experiment 1, 336 birds were offered diets progressively diluted with lignocellulose, starting from a diet with 3,105 (kcal ME/kg) and 20% CP. There was a significant interaction between infection and diet on ADFI during the acute stage of infection (d 17 to 21): for control birds diet dilution decreased ADFI and consequently reduced energy and CP intake. For infected birds, diet dilution increased ADFI, leading to the same energy and CP intake across diets. Oocyst excretion and villi length to crypt depth ratio (VCR) were constant across infected treatments. In Experiment 2, 432 birds were offered diets with constant ME (3,105 kcal/kg), but different CP contents (24, 20, 26, and 12%). Infection significantly reduced ADFI. Although there was no interaction between infection and diet on ADFI, there was an interaction on CP intake during the acute stage of infection. Infected birds on the 20% CP diet achieved the same CP intake as uninfected birds. There were no differences in the VCR and ADG of the infected birds on 24, 20 and 16% CP treatments, but birds on 12% had the lowest ADG and excreted more oocysts. We suggest that during infection, birds target a nutrient resource intake, which appears to be beneficial for infection outcomes, while at the same time they avoid excess protein intake. We conclude that different mechanisms regulate ADFI in infected and uninfected birds.

Publication metadata

Author(s): Taylor J, Sakkas P, Kyriazakis I

Publication type: Article

Publication status: Published

Journal: Poultry Science

Year: 2022

Volume: 101

Issue: 1

Print publication date: 01/01/2022

Online publication date: 13/10/2021

Acceptance date: 08/10/2021

Date deposited: 23/06/2022

ISSN (print): 0032-5791

ISSN (electronic): 1525-3171

Publisher: Elsevier Inc.


DOI: 10.1016/j.psj.2021.101535

PubMed id: 34794080


Altmetrics provided by Altmetric


Funder referenceFunder name
613574European Commission