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

Abstract

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.

The effects of arginine and branched-chain amino acid supplementation to reduced-protein diet on intestinal health, cecal short-chain fatty acid profiles, and immune response in broiler chickens challenged with Eimeria spp.

“…It has been reported that the mTOR pathway is more sensitive to BCAA in the skeletal muscle ( Yoshizawa et al, 2013 ) where the majority of its uptake occurs ( Holeček, 2018 ). Consequently, BCAA supplementation could primarily benefit the skeletal muscle for protein synthesis rather than intestinal epithelial cells and immune cells, especially during Eimeria infection, where nutrient availability is reduced due to anorexia ( Taylor et al, 2022 ). This could potentially explain the absence of effects of BCAA supplementation on mTOR pathway in the intestine and CT, which might in turn account for the limited impact of BCAA supplementation on intestinal health and immune response.…”

“…A 2-way ANOVA was conducted for all data except for the histology data to examine the main effects (diet and Eimeria challenge) and their interaction. For the histology data, a 2-way ANCOVA was performed with the body weight ( BW ) at sampling as a covariate to account for a priori differences in performance ( Sakkas et al, 2018 ; Taylor et al, 2022 ). When significant differences were observed, Tukey's multiple comparison test was applied to separate and compare the treatment means.…”

Dietary Fiber Level Improve Growth Performance, Nutrient Digestibility, Immune and Intestinal Morphology of Broilers from Day 22 to 42

“…Oikeh et al reported that the ADG/BW (body weight) were decreased in broilers fed a basal grower diet diluted with 0%, 5%, 10% or 15% lignocellulose [ 35 ]. Another study reported that the ADFI was increased with the diets dilution in broilers infected with Eimeria maxima, and the diets were a basal grower diet diluted with 0%, 5%, 10% or 15% lignocellulose [ 36 ]. The inclusion of fiber, such as oat hulls, wood shavings and soybean hulls, has been shown to increase feed efficiency by 3–5% and increase body weight by 2–5% when included at 3–5% in the broiler diets [ 23 , 24 , 25 ].…”

Phase-specific outcmes of arginine or branched-chain amino acids supplementation in low crude protein diets on performance, nutrient digestibility, and expression of tissue protein synthesis and degradation in broiler chickens infected with mixed Eimeria spp.

“…The growth performance response was partitioned into phases relative to the day of inoculation (prepatent, acute, recovery, and compensatory growth): prepatent (d0–3pi), acute (d4–7pi), recovery (d8–14pi), and compensatory phase (29–35d); the periods were defined as per Taylor et al (2022) . The end of prepatent, acute, recovery, and compensatory phases, when birds were weighed, corresponded to 4, 7, 14, and 21 d postinnoculation ( dpi ).…”

“…Coccidiosis is a widespread enteric disease caused by protozoan parasites belonging to the Eimeria genus. Eimeria infections lead to reduced availability of dietary amino acids ( AA ) for broiler growth, primarily due to pathogen-induced anorexia and disruptions in amino acid digestion and absorption ( Taylor et al, 2022 ). This, in turn, results in poor growth and elevated mortality rates ( Teng et al, 2020 ; Sharma et al, 2022 ).…”