Investigating Acute-Phase Proteins in Feces of Broiler Chickens Undergoing Necrotic Enteritis: A Potential Tool for Assessment and Monitoring.

Necrotic enteritis (NE) is a prevalent bacterial disease in the broiler industry caused by Clostridium perfringens. Current monitoring and diagnostics for NE rely on invasive necropsy and subjective lesion scoring. This study introduces fecal acute-phase proteins (APPs) as novel, noninvasive biomarkers for NE, an understudied approach offering objective, scalable monitoring in poultry health. APPs, secreted by the liver and innate immune cells during inflammation and injury, can offer potential insights into disease development. A total of 276 Ross 308 male broilers were divided into four treatments: negative control (NC; uninfected birds fed a grower corn-soybean-based diet); positive control (PC; uninfected birds fed a diet containing wheat, fish meal, and lard referred to here as the proinflammatory diet); coccidiosis (cocci; birds infected with Eimeria maxima fed a proinflammatory diet); and NE (birds coinfected with E. maxima and C. perfringens fed a proinflammatory diet). On Day 21, birds from all treatments were randomly selected and euthanized to collect colon content and evaluate lesion scores, and 64 samples were selected for APP fecal evaluation. Proteins were extracted by using NP-40 lysis buffer, and commercial sandwich ELISAs were conducted to measure the concentrations of the APPs. Data were analyzed using one-way ANOVA, the Tukey test was used to compare means among treatments and groups, and significance was declared when P ≤ 0.05. Calprotectin (MRP-126) concentrations increased about fivefold from NC to PC (P < 0.0001), ∼120-fold from NC to cocci (P < 0.0001), and ∼320-fold from NC to NE (P < 0.0001). The C-reactive protein (CRP) increased about twofold from NC to PC (P = 0.0366), ∼10-fold from NC to NE scores 2-3 (P < 0.0001), and ∼100-fold from NC to NE scores 4-5 (P < 0.0001). These findings underscore the potential of MRP-126 and CRP as fecal biomarkers for screening and detecting inflammation associated with NE in broiler chickens.