Evaluation of sorghum ergot toxicity in broilers

Three experiments evaluated the performance of broilers fed sorghum ergot consisting of sphacelia/sclerotia of Claviceps africana present in tailings removed by conditioning of seed from grain sorghum hybrid seed production fields near Uvalde (Experiments 1 and 2) and Dumas (Experiment 3), Texas. Percentage sphacelia/sclerotia and total alkaloid content, respectively, in sorghum ergot tailings were 8% and 11.3 ppm for Uvalde and 75% and 235 ppm for Dumas. Sorghum ergot and control sorghum diets were based on the NRC (1994) requirements for starting broilers. In Experiment 1, neither growth nor feed efficiency were significantly reduced in male broilers fed sorghum ergot from hatch to 3 wk of age, but liver weights were significantly greater than those in the control. In Experiment 2, straight-run broilers were raised to 6 wk of age in floor pens using a three-phase feeding program. Sorghum ergot significantly reduced gain in 4-wk-old broilers and cumulative body weight at 5 wk. Feed conversion was significantly reduced during all three phases of feeding. In Experiment 3, control sorghum and the 75% ergot tailings were added to corn-soy basal diets at rates of 2.5, 5, and 10% by weight and fed to male broilers from hatch to 3 wk of age. Sorghum ergot did not significantly reduce growth, but, during Weeks 2 and 3, feed-to-gain ratios were higher. Neither type nor concentration of sorghum ergot significantly affected relative liver weights. We did not observe significant mortality or obvious symptoms of ergot toxicity, such as necrotic lesions of the feet or vesicular dermatitis of the comb, in any of the three experiments.