An 8-week study was piloted to establish the effect of Pleurotus ostreatus (PO) extract (Oyster mushroom) on health status and quality attributes of meat. One hundred and eighty (180) day old Cobb chicks were allotted into three treatments and orally administered extract of Pleurotus ostreatus at 0 (control), 2000 and 4000 mg/L. Haematological indices, serum metabolites, quality attributes of meat and oxidative stability of meat were determined. Oral administration of PO had no effect on haematological indices and some serum metabolites except serum albumin and calcium. Thiobarbituric acid (TBARs) in blood was lowered in 4000 mg/L group at week 4 and 8 of growth. Crude protein and water holding capacity (WHC) increased as level of oral administration of PO increased with the highest values in 2000 mg/l and 4000 mg/L groups. Glutathione Peroxidase (GSH-Px) activity in meat tissue was highest in the 4000 mg/L treatment while Thiobarbituric Acid Reactive Substances was statistically lowest and similar in the control and 4000 mg/L groups. It is concluded that Pleurotus ostreatus extract can be orally administered up to 4000 mg/L as an antioxidant in birds in order to decrease lipid peroxidation in birds and improve meat quality and oxidative stability.