Effects of
dietary fat,
protein, and
methionine levels and the type of dietary grain in
nicarbazin-containing diets on the growth response of broiler chicks were evaluated in five experiments in a factorial design.
Nicarbazin at levels ranging from 100 to 200 mg/kg significantly (P less than .05) depressed
weight gain and feed efficiency. Feed intake was significantly reduced only when
nicarbazin was used at levels of 150 and 200 mg/kg. The latter concentration also significantly decreased water intake and water:feed ratio.
Nicarbazin, at a level of 150 mg/kg, did not affect dietary metabolizable energy content or the retention of
nitrogen and dry matter. A higher level of
soybean oil (3.5 vs. .5 or 1.0%) did not counteract the growth-depressing effects of 100, 150, and 200 mg
nicarbazin/kg. The growth-depressing effect of the highest dose also was not affected by increasing the
protein level from 18.2 to 20.4%. Neither type of dietary grains (corn vs. sorghum) nor supplemental
methionine level affected the toxicity of 125 mg
nicarbazin/kg. Water intake and water:feed ratio were significantly increased due to elevation of
dietary protein and fat levels. It was concluded that the severity of the growth-depressing effect of
nicarbazin on chicks was not dependent on the levels of dietary
unsaturated fat,
protein, and
methionine.