The effect of dietary copper sulfate on infectious proventriculitis

Oral inoculation of day-old broiler chicks with a crude homogenate of affected proventricular tissue, or the same homogenate filtered through a .2 micron filter caused proventricular lesions similar to those responsible for carcass contamination of broilers at processing. Dietary copper sulfate (CUS) has also been shown to produce similar lesions. In this study, we investigated the interaction between crude proventriculus homogenate or filtered proventriculus homogenate and 1 g/kg CUS added to a standard chicken diet. Cobb x Cobb female broiler chicks were distributed into six groups with four replicate battery pens per group. Birds were fed either a standard broiler starter diet or the same diet with 1 g/kg CUS. Each dietary treatment was inoculated per os with 1 mL of either sterile saline, unfiltered homogenate, or filtered homogenate. Both crude and filtered homogenates had a much stronger affect on proventriculus score than did Cu by itself, resulting in no interaction between either homogenate or filtrate and CUS. There was a significant and possibly antagonistic interaction on proventriculus relative weights in the CUS by filtrate group during Week 1 and a synergistic interaction in the CUS by homogenate group during Week 4. Body weights were decreased in birds fed homogenate or CUS, but not in birds fed filtrate. There was a protective effect shown by filtrate on body weight of birds fed both filtrate and CUS only during Week 1. There was a synergistic decrease in body weight of birds fed homogenate and CUS during Week 2. Overall feed conversion efficiency was significantly decreased in the homogenate treatment (P = .04) and decreased in the birds fed CUS (P = .1). There was a (4.2 vs 2.3) (P = .1) decrease in feed conversion efficiency in birds fed both homogenate and CUS. Natural exposure to low levels of the infectious agent present in the homogenates may interact with excess dietary CUS, resulting in increased proventriculus size and decrease in body weight and feed conversion efficiency.