The brain plays a critical role in controlling reproduction through the hypothalamus-pituitary-gonadal (HPG) axis in vertebrates. Turbot (Scophthalmus maximus) has become an economically important marine fish in Europe and North China. Previous research investigating turbot reproduction has focused on the role of the HPG axis in regulating egg and sperm production. However, the morphology and histology of the organs in the HPG axis have not been studied. In this study, we investigated the morphology and histology of brains in female and male turbot at different stages of gonadal development. The results showed that the brains of both female and male turbot were composed of seven parts that are typical of advanced teleosts: the telencephalon, diencephalon, cerebellum,hypothalamus, pituitary gland, myelencephalon, and olfactory bulbs. The telencephalon was well-developed and contained five distinct lobes, with the contiguous diencephalon at the caudal portion. The torus longitudinales and rostral torus semicircularis of the mesencephalon flattened along the dorsal surface, and the rostral corpus cerebellum was located in the dorsal portion. The actual total brain volume in mature males was significantly greater (p<0.05) than that of females with gonadal development. Notably, the pituitary volume in male turbot significantly increased (p<0.05) from immature to mature stage, but this difference did not occur in females. The data together illustrate a distinct sex difference in the turbot brain during gonadal development, providing insight into their HPG axes.

Chunyan Zhao;Liang Chi;Yongshuang Xiao;Bing Li;Yunliang Lu;Yanting Cui;Wenqi Wang;Jun Li

School of Marine Science and Engineering,Qingdao Agricultural University,Qingdao 266109,China;College of Veterinary Medicine,Qingdao Agricultural University,Qingdao 266109,China;CAS Key Laboratory of Experimental Marine Biology,Center for Ocean Mega-Science,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Marine Biology and Biotechnology Laboratory,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China

海洋学报（英文版）

[1]Chunyan Zhao;Liang Chi;Yongshuang Xiao;Bing Li;Yunliang Lu;Yanting Cui;Wenqi Wang;Jun Li-.Morphological and histological changes in the brains of turbot (Scophthalmus maximus) with gonadal development)[J].海洋学报（英文版）,2022(12):115-122

turbot,Turbot,diencephalon,myelencephalon,longitudinales,semicircularis,mesencephalon

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