The Effect of Thyme and Rosemary Powder Supplementation in Aflatoxin B1 Contaminated Diet on Liver Histopathology of Rainbow Trout (Oncorhynchus mykiss)

Inroduction & Objective: Dietary aflatoxin contamination cause liver tissue damage and
immunosuppression in aquatic animals. Active metabolites of some medicinal herbs have promising effects
on controlling fungi growth and aflatoxin contamination of feedstuffs. This study was to investigate liver
pathogenesis of aflatoxin B1 and protective potency of rosemary and thyme powder in rainbow trout. Therefor, 225 fish with an average weight of 90±3 g were allocated amongst
three treatments including control group (diet devoid of aflatoxin B1), treatment two (diet included with 50
ppb aflatoxin B1) and treatment three ( 50 ppb aflatoxin B1 contaminated diet containing 2% rosemary and
2% thyme powder). After 6 weeks of feeding on the diets, hepatic tissue pathologies were studied using H&E
and Masson-Trichrom staining methods. Serum inflammatory enzymes activity were also assayed. H&E staining results were indicative of immune cell infiltration, congestion, edema and necrosis
of hepatic tissue in groups two and three, with severe tissue alterations in third experimental group. Mason-
Trichrom showed advanced tissue fibrosis in treatment three (p<0.05). Inflammatory enzymes activity also
showed higher activity in fish fed on third experimental diet (p<0.05). Aflatoxin B1 resulted in hepatic tissue pathologies and rosemary and thyme powder
inclusion to such a diet exacerbated the pathological alterations.