Changes of vitellogenin and Lipase in captive Sterlet sturgeon Acipenser ruthenus females during previtellogenesis to early atresia

Abstract

Plasma chemistry, lipid metabolism and vitellogenin gene expression of captive Sterlet sturgeon Acipenser ruthenus were studied in different maturity stages. A total of 32 fish were sampled, and maturity stages were identified on the basis of histological criteria and direct observation. Females were classified to four groups: previtellogenic, vitellogenic, post-vitellogenic, and atresia. Blood, gonad and liver tissue samples were taken through non-lethal biopsy. Our results showed that plasma levels of glucose, cholesterol, triacylglycerol, high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, calcium, phosphorus, alkaline phosphatase activity, albumin and total protein increased during ovarian development and were highest at post-vitellogenic stage. The lowest amounts in atresia stage demonstrate that lipid and energy imbalance was related to reabsorption and digestion of the yolk. These results suggested that the VLDL was the main plasma lipoprotein component of Sterlet. We determined that lipoprotein lipase and hepatic lipase activity increased during vitellogenesis process which suggested the role of lipase enzymes in regulating blood lipid metabolism. RT-PCR analysis indicates that Vitellogenin (VTG) mRNA could be detected both in livers and ovaries of female Sterlet. Throughout the study, the expression level of VTG gene showed an increase both in ovaries and in livers reaching its peak at late vitellogenesis stage. This strongly indicated a relation between VTG mRNA and ovarian development.

Growth performance and physiological changes of holding juvenile Siberian sturgeon at different sizes in rearing units

“…The biuret method was used to measure the total protein at 37ºC. All measurements were carried out by a spectrophotometer (Unico, New Jersey, USA) using Pars Azmoon kits (Karaj, Iran) (Akhavan, Salati, Falahatkar, & Jalali, ). The cortisol concentration of plasma was assessed based on the enzyme‐linked immunosorbent assay (ELISA) kits (Monobind, Lake Forest, USA) at 96‐well microplates in ELISA reader (Epoc, BioTek, USA) at room temperature (Barry, Lapp, Kayes, & Malison, ).…”

Expression profile of star and cyp19 and plasma sex steroid during gonad development from previtellogenesis to early atresia in captive Sterlet sturgeon,Acipenser ruthenus

“…The male fish were returned to their tank, whereas the females removed for next samplings. Gonadal stage determination was performed based on appearance and the histology reported in (Akhavan, Salati, Falahatkar, & Jalali, ). Thirty two fishes; (eight fishes from each developmental stage including previtellogenic [PV], VTG, POV and atresia) were selected and used for sampling.…”

“…The relative star and cyp19a gene expression were quantified using equation 2 −(ΔCt sample − ΔCt control) method (Livak & Schmittgen, ). For whole process description see Akhavan et al ().…”

Oogenesis is accompanied by cyclic morphological changes in hepatocytes of Neotropical freshwater fish Piabina argentea

“…In the liver, E2 stimulates hepatocytes to produce vitellogenin and choriogenin, where they participate in the formation of the yolk and zona pellucida during oocyte maturation (Senthilkumaran, Yoshikuni, & Nagahama, ). The yolk accumulates in the cytoplasm of oocyte I that increase in diameter (Akhavan, Salati, Falahatkar, & Jalali, ). Thus, FSH regulates E2 secretion and incorporation of vitellogenin into oocyte I (Yaron & Levavi‐Sivan, ).…”

“…The main source of energy for embryonic development in fish is the yolk, which is derived primarily from vitellogenin (Akhavan et al., ). For most fish, the liver is the main source of vitellogenin that is produced and transported to the ovary through the bloodstream during vitellogenesis.…”