Effects of gingko, Ginkgo biloba extract on metabolic hormones, liver histology, and growth parameters of rainbow trout, Oncorhynchus mykiss exposed to diazinon

Abstract

The medicinal plant, Ginkgo biloba (GB) has been used for centuries in traditional medicine to improve health in human. In this study, we investigated for the first time the protective effects of GB against the toxic effects of the organophosphate pesticide (PC), diazinon on metabolic hormones, plasma glucose, liver histology and growth parameters of rainbow trout, Oncorhynchus mykiss. In non-diazinon-exposed fish, groups supplemented with 1 and 2 g GB/kg diet showed higher levels of plasma thyroid hormones [(Triiodothyronine (T₃) and thyroxine (T₄)], body weight index (BWI %) and specific growth rate (SGR %) compared to control (non-GB-supplemented fish) (p < .05). The supplementation of fish with 4 g GB/kg diet decreased the BWI %, SGR %, and plasma thyroid hormones (p < .05). FCR values significantly decreased in fish supplemented with 1 and 2 g GB/kg diet (p < .05). Also, no alternations were found in plasma levels of cortisol and glucose and liver histology during 60 d experiment (p > .05). In diazinon-exposed fish, thyroid hormones, BWI %, and SGR % significantly decreased during exposure period in all experimental groups (p < .05). FCR values significantly increased in control and fish supplemented with 0.5 and 4 g GB/kg diet (p < .05). No significant changes were observed in FCR values of fish fed 1 and 2 g GB/kg diet (p > .05). The cortisol levels significantly elevated during exposure period in control and groups fed 0.5, 1, and 4 g GB/kg diet, while this hormone remained unchanged in fish supplemented with 2 g GB/kg diet (p > .05). The plasma levels of glucose significantly elevated in fish supplemented with 2 g GB/kg diet (p < .5). Based on histological observations, the severity of liver damages was lower in GB-supplemented fish compared to non-supplemented ones (p < .5). The lowest liver lesions were observed in fish supplemented with 1 and 2 g GB/kg diet (p < .5). In conclusion, the findings of this study showed that GB at optimum dietary levels (1–2 g GB/kg diet) could stimulate the growth and also moderate the growth suppressing effects, stress, and liver tissue damages induced by diazinon.

KEYWORDS:

• Ginkgo biloba
• fish
• growth
• hormone
• rainbow trout

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by University of Jiroft under the grant No. 4813–97-7.