Pleurotus ostreatus is able to bioaccumulate several metals in its cell structures; however, there are no reports on its capacity to bioaccumulate iron. The objective of this study was to evaluate cultivation variables to increase iron bioaccumulation in P. ostreatus mycelium. A full factorial design and a central composite design were utilized to evaluate the effect of the following variables: nitrogen and carbon sources, pH and iron concentration in the solid culture medium to produce iron bioaccumulated in mycelial biomass. The maximum production of P. ostreatus mycelial biomass was obtained with yeast extract at 2.96 g of nitrogen L −1 and glucose at 28.45 g L −1 . The most important variable to bioaccumulation was the iron concentration in the cultivation medium. Iron concentration at 175 mg L −1 or higher in the culture medium strongly inhibits the mycelial growth. The highest iron concentration in the mycelium was 3500 mg kg −1 produced with iron addition of 300 mg L −1 . The highest iron bioaccumulation in the mycelium was obtained in culture medium with 150 mg L −1 of iron. Iron bioaccumulation in P. ostreatus mycelium is a potential alternative to produce non-animal food sources of iron.

ABSTRACT. Translocation of minerals from substrate to mushrooms can change the medicinal characteristics, commercial value, and biological efficiency of mushroom. In the present study, we demonstrated that addition of iron to the substrate reduces the yield of Pleurotus ostreatus mushroom. The biological efficiency of the mushroom varied from 36.53% on the unsupplemented substrate to 2.08% for the substrate with 500 mg/kg iron added. The maximum iron concentration obtained for mushroom was 478.66 mg/kg (dry basis) and the maximum solubility in vitro was 293.70 mg/kg (dry basis). Iron translocation increased the ash and protein content, reduced antioxidant activity, and enhanced the aroma and flavor characteristics of the mushroom. However mushroom has higher amounts of iron than vegetables like collard greens, it is not feasible to use mushrooms as the only dietary source of iron. The study also indicated that because of more bioaccumulation of iron in mycelium than in the mushroom, mycelium and not mushroom, could be a better alternative as a non-animal iron source.

Many alternative compounds have been tested to improve poultry performance but few of them have previously used mycelial-colonized substrate to partially replace standard diet in broiler chickens. The objective of this study was to evaluate broiler chicken production, health, and meat sensory characteristics, with partial replacement of the standard diet by Pleurotus ostreatus-colonized substrate. One hundred fifty 1-day-old male Cobb chicks were given standard diet partially replaced by 0, 5, 10, 100, or 200 g·kg⁻¹ of P. ostreatus-colonized substrate and randomly distributed into five treatments. Each treatment had three replicates, with 10 birds per replicate, totaling 30 birds. The replacement of the standard diet by 10 g·kg⁻¹ of colonized substrate increased (P≤0.05) chicken body mass up to 57% at 21 days, and up to 28% at 42 days. In general, partial replacement of standard diet by colonized substrate increased hematocrits and typical lymphocytes, and reduced low density lipoproteins. Also, it reduced chicken production period up to 21% and there is no meat taste alteration. The use of P. ostreatus-colonized substrate in chicken feeding is an alternative method to improve broiler chicken production.