Immunomodulation Effect of Aqueous Extract of the Artist's Conk Medicinal Mushroom, Ganoderma applanatum (Agaricomycetes), on the Rainbow Trout (Oncorhynchus mykiss).

Abstract

It is well known that innate immunity in fish can be activated by many synthetic and natural immunos-timulants; several natural substances induced immunity in fish in previous surveys. This study discussed data regarding the effect of Ganoderma applanatum aqueous extract on the defense mechanisms of rainbow trout in feeding trials. Fish were fed 250, 500, and 1000 mg extract/kg diet 4 times daily. Growth, humoral parameters, lysozyme activity, and serum protein concentrations were assessed after a period of 45 days. The results indicated that dietary supplementation with the mushroom extract did not positively affect the growth of fish compared with the control group. The numbers/amounts of red blood cells, hemoglobin, hematocrit, white blood cells, monocytes, and neutrophils increased significantly in the treated fish. Other red cell indices, including mean corpuscular volume, mean corpuscular hemoglobin concentration, and mean corpuscular hemoglobin values, indicated no significant differences among all groups. The values of immunologic parameters in the all treatment groups were elevated, especially with a concentration of 1000 mg mushroom extract/kg diet: lysozyme activity, 50.00 ± 1.15 U/mL; total protein, 4.40 ± 0.12 g/dL; albumin, 2.40 ± 0.23 mg/dL; total immunoglobulin, 23.50 ± 0.76 mg/dL. These findings suggested the potential ability of G. applanatum aqueous extract to activate immunologic parameters in rainbow trout.