Dried distillery yeast can be used as a source of energy and protein in broiler diets, but producers should pay attention to inclusion rates to avoid affecting feed conversion and potentially disrupting the birds’ gut microbiome, a Polish study suggests.
Scientists tested the inclusion of the deactivated yeast at three different levels — 3, 6 and 9% — in the starter, grower and finisher diets of 112 birds.
They found no adverse effects of the test diets on bird survivability, but that those receiving the 3% yeast had significantly better feed conversion than those fed the diet with 9%. This led them to conclude that yeast inclusion in growing birds’ feed should not exceed 3%.
“Based on the average values, a trend can be observed that birds receiving 3% distillery yeast in their feed had higher body weight (27 and 35 days), body weight gain (1–35 days), better feed conversion (1–35 days), and higher European Production Efficiency Factor compared to birds receiving 6% and 9% yeast additives and the control group,” they wrote in the journal Agriculture.
Yeast brings gut changes
During the initial 10 days covered by the starter diet, birds consumed significantly more feed on the control than on the experimental diets, but this was not seen during the other fattening periods.
The different diets also had an impact on the microbial content of birds’ guts. As the proportion of dried yeast in the diets increased, the scientists saw a decrease in the number of microorganisms isolated from faeces samples, regardless of growing period. However, significant effects on the diversity and quality of microorganisms were only seen when 9% yeast was used.
Diets featuring dried yeast did not have a significant impact on microorganisms associated with probiotic qualities, the researchers stressed, while the additive fulfils the function of a prebiotic by reducing the colonisation of the gut by pathogens.
“A properly balanced diet containing distillers yeast can be used as a good source of energy and protein in broiler diets and can serve as a cost-effective alternative to soybean meal,” they concluded.
