Hydrocarbon grown yeast in rations for chicks

Synopsis The results of three experiments in which a yeast grown on gas oil was incorporated in chick rations are reported. Mean digestibility coefficients of the yeast were 72 per cent for dry matter, 74 per cent for organic matter and 80 per cent for protein. The mean metabolisable energy value was 2550 kcal/kg. In one of the feeding experiments it was found that 7.5 per cent of the fish meal in the control ration could be replaced by the yeast with no adverse effect on performance. When all of the fish meal in the control ration, i.e. 10 per cent, was replaced by the yeast, the effect on live‐weight gain of the chicks was negligible. However, when all of the fish meal and part of the soyabean meal in the control ration was replaced by 15 per cent yeast, some depression in chick growth occurred. Similar rations containing a commercial sample of torula yeast gave significantly poorer performance than the corresponding controls at both the 10 and 15 per cent levels of inclusion of the torula yeast.