|
|
Experiments with Low-Protein Diets Three experiments were conducted at Iowa State University comparing
the performance and whole-body composition of broilers chicks fed low-protein
diets supplemented with crystalline amino acids. Day-old chicks were
fed a common corn-soybean diet (23% crude protein) for seven days and
then allocated to dietary treatments. Ten chicks per floor pen and six
replications per treatment were fed low-protein diets (19-20% crude
protein, 3200 ME kcal/kg) supplemented with crystalline essential and
nonessential amino acids. In all experiments, chicks fed the low-protein
diets grew slower, had less efficient feed conversions and retained
less nitrogen and higher lipid carcasses compared to the chicks fed
the control diets, despite the additions of crystalline essential and
nonessential amino acids. Chicks fed the low-protein diets excreted
less nitrogen than did chicks fed the 23% protein diets and nitrogen
excretion increased linearly with nitrogen intake. The investigators
cautioned nutritionists to consider chick performance before lowering
diet protein levels in broiler diets. Lower protein diets may reduce
nitrogen excretion, but reduced performance and feed utilization may
negate environmental advantages. |
