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
