ABSTRACT

This investigation was conducted to study the productivity and bio-safety of Pleurotus ostreatus fruit bodies cultivated on Hydrochloric acid (HCl)-induced oil palm bunch (OPB) substrate. Percentage solutions (0.1-0.5%) HCl were used to induce changes on the initial pH (10.1) of 1400g of OPB replicated 7 times; to 8.2, 7.8, 7.4, 7.1, 6.1 and control (9.0) respectively. One way analysis of variance (ANOVA) was adopted for data analysis using SPSS version 20.1. Means were separated by Duncan Multiple Range Test (DMRT) at p≤0.05%. Fruiting was delayed (19days) in 0.5%HCl substrate while control fruited after12 days. 24 Wistar albino rats made into six groups of four (4) replications, were administered 500ml/kg aqueous extract of mushroom at 24hr interval, for 21days. 0.5% substrate induced the highest (1799.10g/kg) fruit body yield, number (705) and biological efficiency (137.97%) while control produced the lowest (865g/kg, 424 and 61.79.3%). Fruit bodies from 0.2% HCl OPB substrate had the highest mean cap diameter (7.75±0.29cm), stipe length (3.00±0.12cm) and Weight (9.02±0.79g) while those of 0.1% (5.96±0.23cm), 0.4% (2.44±0.07cm) and 0.1% (5.23±0.52g) had the lowest. Fruit bodies from 0.4% had the highest (16.72±0.57mg/100g) vitamin B₁ content among other levels while the lowest concentrations of vitamins A and E were observed at all levels. Phenolics were highest at 0.1% (188.96±6.01%) but lowest at (0.2% (106.56±1.76%). Tannins increased from 101.06% in fruit bodies from 0.2% - 134.68 in those of 0.5% substrate groups, unlike other levels. Alkaloids were highest at 0.2% (46.87±0.43%) and terpenoids at control. Moisture (9.07±0.15%) and Protein (24.98±0.03%) contents were highest at 0.5%HCl while control (80.09±0.09%) had the highest carbohydrate. Ash, ether extract (E.E) and crude fiber (CF) were low across all treatment levels and control. Sodium (149.85±6.32) and potassium (5.07±0.46mg/100g) were highest in mushrooms of 0.5%HCl while Chlorine and Calcium tend to increase with increase in percentage HCl. Concentrations of Zinc (181.07±1.22mg/100g) and Iron (197.70±20.01mg/100g) were highest in 0.1% HCl while those of Selenium, Lead and Copper were among the lowest. No mortality was recorded among the animals used. Rats of 0.2 (690.00±13.54 ×10⁹/L) and 0.3% (13800.00±115.47×10⁹/L) groups had the highest white and red blood cells. Highest platelets count of 237.50±23.94 ×10⁹/L was recorded in the control, 0.1 and 0.5%HCl groups. 0.1, 0.4 and 0.5% groups had the highest level of haemoglobin while 0.4(42.25±1.32%) and 0.5% (42.00±0.82%) groups had the highest packed cell volume. Liver function test showed that 0.3HCl group had the highest aspartate aminotransferase AST (37.08±1.36IU/L) and alkaline phosphatase (ALT) (29.71±3.68IU/L) levels while control had the highest alanine aminotransferase (ALP) (23.90±1.15 IU/L). Albumin and Bilurubin levels were not affected by the mushroom extract while Urea and serum protein levels of 0.1 (35.83±1.31 mmol/L) and 0.3%HCl (6.00±0.16 mmol/L) groups had the highest. GSH, GPx, MDA, SOD and catalase were not significantly affected at all levels (0.1-0.5%) groups. Both In vitro and In vivo bio-safety studies were not significant (p ≥ 0.5), suggesting that the mushrooms could be safe for human consumption. Oil palm bunch should therefore be adopted in the commercial production of the Oyster mushroom.