INTERACTION OF CALCIUM AND SULPHUR IN CANOLA AND SOYBEAN MEAL DIETS FED TO BROILER CHICKS

Abstract

Several studies were undertaken to investigate the interaction of calcium and sulphur when added to semi-purified diets containing either canola or soybean meal, as the only protein source. High levels of sulphur supplementation reduced the performance of birds fed diets containing both sources of protein; however, it was more severe with canola than with soybean meal diets. Sulphur coming from methionine resulted in poorer bird performance than that coming from cystine. Increasing dietary calcium levels from low to close to the requirement level partially alleviated the detrimental effects of the higher sulphur supplementation. Liver weight was not altered, as a percent of body weight, at the high sulphur levels, suggesting little or no liver involvement in the reduced performance noted. Reduced performance often reported for birds fed canola versus soybean meal diets may well be due, in part, to the higher level of sulphur in canola meal than soybean meal, in particular the inorganic sulphur fraction. However, the present study utilized diets containing 40% canola meal, which is much higher than would be found in practical type diets. Thus care must be taken in extrapolating the present findings to practical conditions. Key words: Chickens, canola, calcium, sulphur, methionine