ABSTRACT
The study investigated the probiotic effects of Saccharomyces cerevisiae on pullets
development and hen-day egg performance of the layers. A total of 120 chicks were
brooded for 4 weeks, after which 100 pullets were randomly selected and placed in
4 groups (A-D) of 25 birds each. Groups A, B and C had their feed supplemented
with S. cerevisiae at graded levels of 0.6, 0.8 and 1.0 g/kg of feed respectively.
Group D diet did not contain S. cerevisiae (control). The diets for all the groups
contained 25% PKC and they were isocaloric and isonitrogenous. The pullets were
weighed weekly.

At 9th, 15th and 40th week of age, 5 birds were randomly selected
from each pen and 2 ml. of blood collected into an EDTA bottle for haematology.
The blood sample was used to determine packed cell volume (PCV), haemoglobin
concentration (HbC), total leukocyte count (TLC) and differential leukocyte count
following standard procedures. At 10th and 40th week of age, 3 pullets were
randomly selected from each group and placed in four different cages. The quantity
of feed consumed and faeces voided were determined, proximately analyzed and
used to determine the apparent digestibility of the diets. Eggs were collected three
times daily, weighed and their external qualities were assessed. At the 20th week in
lay, another set of 5 layers were randomly selected from each group and 5 ml of
blood were collected from each bird and allowed to clot. The serum harvested was
used to evaluate the serum biochemistry of the layers. At the 22nd week in lay, ten
eggs were randomly selected from each group and were used to determine the egg