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 throug h a .2 mu m filter caused proventricular lesions similar to those resp onsible for carcass contamination of broilers at processing. Dietary c opper sulfate (CUS) has also been shown to produce similar lesions. In this study, we investigated the interaction between crude proventricu lus homogenate or filtered proventriculus homogenate and 1 g/kg CUS ad ded to a standard chicken diet. Cobb x Cobb female broiler chicks were distributed into six groups with four replicate battery pens per grou p. Birds were fed either a standard broiler starter diet or the same d iet with 1 g/kg CUS. Each dietary treatment was inoculated per os with 1 mt of either sterile saline, unfiltered homogenate, or filtered hom ogenate. Both crude and filtered homogenates had a much stronger affec t on proventriculus score than did Cu by itself, resulting in no inter action between either homogenate or filtrate and CUS. There was a sign ificant and possibly antagonistic interaction on proventriculus relati ve weights in the CUS by filtrate group during Week 1 and a synergisti c interaction in the CUS by homogenate group during Week 4. Body weigh ts were decreased in birds fed homogenate or CUS, but not in birds fed filtrate. There was a protective effect shown by filtrate on body wei ght 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 d uring Week 2. Overall feed conversion efficiency was significantly dec reased in the homogenate treatment (P = .04) and decreased in the bird s 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 e xposure to low levels of the infectious agent present in the homogenat es may interact with excess dietary CUS, resulting in increased proven triculus size and decrease in body weight and feed conversion efficien cy.