Suspect Biogenic Amine Toxicity in an Experimental Broiler Flock

Unexpected illness and deaths occurred in an experiment to determine the efficacy of four antibiotic feed additives in a necrotic enteritis challenge model. The experimental basal diet was based on a commercial wheatsoy formulation and contained xylanase and phytase at the recommended rates of inclusion. The starter diet in week 1 (days 0-7) was fed as a mash. Adhering to the challenge model, all birds were fed a high protein diet (50 % commercial starter, 50 % fishmeal) in the second week post-hatch (days 7-14). The fishmeal diet was fed as a short cut 5 mm pellet. All diets were mixed at the University of New England, and pelleted using a small scale 'cold' pelleter, with pellet temperatures ranging from 54°C to 81°C. The experimental antibiotics were incorporated into the diets. Challenged and unchallenged negative controls (no antibiotic) were included in the experimental design. Twelve hundred and ninety-six broiler chicks were split into 54 pens of 24 birds (1:1 sex ratio per pen). All birds were fed ad libitum and had free access to water via drinker nipples. On day 9, all birds from challenged treatments were given an oral suspension containing sporulated oocysts of 'Eimeria spp'. whilst unchallenged birds received sterile PBS. As part of the model, challenged treatments were to be inoculated with 'Clostridium perfringens' (scheduled to begin on day 14).