Dietary fish oil replacement by soybean oil: Effect on plasma vitellogenin, sex steroids and ovarian steroidogenesis in Chinese strip-necked turtles (Mauremys sinensis)
In order to investigate the effects of dietary fish oil replacement, the turtles (Mauremys sinensis) were fed four experimental diets for 10months: FO (100% fish oil), FSO (70% fish oil and 30% soybean oil), SFO (30% fish oil and 70% soybean oil) and SO (100% soybean oil), sampled at pre-vitellogene...
Published in: | Aquaculture Research |
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Main Authors: | , , , , , , |
Format: | Report |
Language: | English |
Published: |
WILEY
2018
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Subjects: | |
Online Access: | http://ir.imde.ac.cn/handle/131551/23598 https://doi.org/10.1111/are.13775 |
Summary: | In order to investigate the effects of dietary fish oil replacement, the turtles (Mauremys sinensis) were fed four experimental diets for 10months: FO (100% fish oil), FSO (70% fish oil and 30% soybean oil), SFO (30% fish oil and 70% soybean oil) and SO (100% soybean oil), sampled at pre-vitellogenesis, vitellogenesis and post-vitellogenesis. The results showed that plasma gonadotropin-releasing hormone (GnRH) levels were the highest at pre-vitellogenesis, which promoted the secretion of gonadotropin and sex steroids. Therefore, plasma luteinizing hormone (LH) and estrogen (E-2) levels were significantly increased at post-vitellogenesis (p<0.05), while follicle-stimulating hormone (FSH) levels increased at vitellogenesis (p<0.05). The FO and FSO groups had significantly higher GnRH and E-2 levels than the other two groups (p<0.05). In addition, plasma vitellogenin (Vtg) levels significantly increased at vitellogenesis and post-vitellogenesis (p<0.05), which were significantly higher in the groups of FO and FSO than SO (p<0.05). Moreover, the expression levels of hepatic estrogen receptor (Er) mRNA were significantly increased at vitellogenesis and post-vitellogenesis while ovarian Cyp191 mRNA were significantly increased at post-vitellogenesis (p<0.05), and both were the lowest in SO. Taken together, the replacement of fish oil with 66.7% soybean oil is feasible. |
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