• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.153-158
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• 1998

Effects of cyclic (c) AMP and G-protein related reagents (3-isobutyl-l-methyxanthine (IBMX), Forskolin (FSK), cholera toxin (CTX), and pertussis toxin (PTX≫ on estradiol-17$\beta$ induced vitellogenin (VTG) induction were examined in primary hepatocyte cultures in rainbow trout Oncorhynchus mykiss. The addition of IBMX, FSK, or CTX to the incubation medium markedly increased VTG production, while PTX was not effective in stimulating the production. It is well known that cAMP regulates phosphorylation and dephosphorylation through mediation of protein kinase A. These results suggest that VTG production is highly dependent on cAMP state in hepatocytes because of its highly phosphorylated nature.

• Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.183-190
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• 2012

The purpose of this study was the purification and characterization of an angiotensin I converting enzyme (ACE) inhibitory peptide purified from enzymatic hydrolysates of rainbow trout Oncorhynchus mykiss muscle. After removal of lipid, the approximate composition analysis of the rainbow trout revealed 24.4%, 1.7%, and 68.3% for protein, lipid, and moisture, respectively. Among six hydrolysates, the peptic hydrolysate exhibited the highest ACE inhibitory activity. We attempted to purify ACE inhibitory peptides from peptic hydrolysate using high performance liquid chromatography on an ODS column. The $IC_{50}$ value of purified ACE inhibitory peptide was $63.9{\mu}M$. The amino acid sequence of the peptide was identified as Lys-Val-Asn-Gly-Pro-Ala-Met-Ser-Pro-Asn-Ala-Asn, with a molecular weight of 1,220 Da, and the Lineweaver-Burk plots suggested that they act as a competitive inhibitor against ACE. Our study suggested that novel ACE inhibitory peptides purified from rainbow trout muscle protein may be beneficial as anti-hypertension compounds in functional foods.

• Development and Reproduction
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• v.4 no.1
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• pp.1-6
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• 2000

Ultrastructure of the zona radiata the micropyle and fertilization process in the rainbow trout (Oncorhynchus mykiss) were examined by light, scanning and transmission microscopes . The egg micropyle of rainbow trout consists of a funnel-shaped vestibule and a tapered canal transversing the zona radiata. The micropyle showed the type with a flat pit leading into a long canal and the micropylar wall showed the clockwise spiral structure. There were a great number of microvilli secreting adhesive materials having trapping function attracting the spermatozoa in the vicinity of micropyle. It was apparent that ridges extended between the projections. In the initial stages of penetration, the spermatozoon still within the micropylar canal attached perpendicularly at its apical tip to the egg surface, then the sperm head was rapidly engulfed by the folded egg surface with its many microvilli. The spermatozoon disappeared from the outer surface of the egg before the fertilization cone completely retracted 250 seconds after insemination. No interconnecting ridges was present in the egg surface. In short, the block to polyspermy to permit entry of a single sperm is considered to be mechanical by the morphological design of the micropyle and fertilization cone.

• Fisheries and Aquatic Sciences
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• v.4 no.4
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• pp.180-185
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• 2001

Al and Cd-induced inhibition of vitellogenin (VTG) production was examined at the estrogen receptor (ER) level in rainbow trout Oncorhynchus mykiss hepatocytes. The binding of $[^3H]$ $estradiol-17\beta\;(E_2)$ to hepatocytes reached a plateau 3 days after addition of $E_2\;(2\times\;10^{-6} M)$to the medium. The binding activity was linearly reduced with the increased concentrations $(-10^{-5}\;M)$ of 4-hydroxy-tamoxifen (4-OHT) and specific binding linearly increased with the increased doses of $[^3H]\;E_2$, indicating that the radioligand bound to ER. Al $(-10^{-4}\;M)$and Cd $(10^{-6}\;M)$ as well as 4-OHT $(10^{-6}\;M)$ significantly reduced the $[^3H]\;E_2$-binding activity by $30­40\%$, while they completely inhibited VTG production. Al and Cd had no effect on $E_2-human$ $ER\alpha$ binding activity at any concentrations used $(-10^5\;nM\;each)$. These results suggested that Al and Cd inhibited VTG production in part by interfereing with the ER level. Inhibitory effects of these metals on the $E_z-dependent$ upregulation of ER activity are also discussed.

• Journal of Aquaculture
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• v.3 no.2
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• pp.145-153
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• 1990

Genetic analysis of rainbow trout populations in hatchery stocks is important in order to develop a strategy for their management. In this study, chromosome number and polymorphisms of diploid and artificially induced triploid rainbow trout are discribed. The relation-ship between chromosomal polymorphism and their economic values for the aquaculture industry are also discussed.

• Fisheries and Aquatic Sciences
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• v.5 no.4
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• pp.251-257
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• 2002

Effects of bisphenol-A (BPA) on vitellogenin (VTG) synthesis and estrogen-estrogen receptor $(E_2- ER)$ binding activity were examined in primary hepatocyte cultures of rainbow trout, Oncorhynchus mykiss. Hepatocytes were precultured for 2 days and then $estradiol-17\beta\;(E_2,\;2\times10^{-6}M)\;BPA\;(10^{-5}-10^{-8}M)$ and/or 4-hydroxy-tamoxifen $(4-OHT,\;10^{-6} M)$ were simultaneously added to the incubation medium. Hepatocytes were cultured for 5 more days and then spent medium was analyzed by SDS-PAGE for VTG production. The addition of BPA to the incubation medium had no effect on the viability of hepatocytes in the culture. On the other hand, BPA increased VTG production in a concentration-dependent way and a significant increment occurred at BPA concentrations greater than $10^{-6}$M. Although VTG was increased by the addition of $E_2\;(2\times10^{-6}\;M)\;or\;BPA\;(10^{-5}M)$, its were reduced by a simultaneous 4-OHT $(10^{-6}\;M)$ addition. BPA inhibited $E_2-human$ ER binding activity by $72\%$ at $10^{-5}$ M of BPA. These results suggested that BPA induced VTG synthesis by BPA-ER binding activity in the hepatocyte of rainbow trout.

• Korean Journal of Animal Reproduction
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• v.15 no.3
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• pp.207-220
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• 1991

This study was carried out to investigate the ultrastructural changes of ooplasm and follicular membrane of oocytes, obtained from 150 of 3-year-old female rainbow trout(Oncorhynchus mykiss). All data were collected from March in 1989 to February in 1990, and from August to October in 1991. The size of the nucleoli and number of the yolk granules increased as the oocyte growed. Yolk granules were deposited in the oocyte as crystalline granules. Due to the presence of large early and late maturing oocytes, their ovaires were enlarged, transparent and granular. The lattice was broken down at hydration, leaving the egg transparent. As thepercentages of fish in LPO and EMO stage increased from September to October, Mean GSI values increased. Follicle cells such as granulosa cell and thecal cell change a squamous into cuboid shape in LPO and EMO stage. Seasonal changes in the microscopic appearance of the ovaries were well correlated with those in bothgonadosomatic index and macroscopic apearance. Under the natural conditions,t he ovarian follicle influences the histological development and periodical secretion of the hormones, sufficient for a oogenesis and gonadal steroid production. The electrophoretic pattern of major band in mature stage was much thicker(70∼110k dalton) than that in previtellogenic phase.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.6
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• pp.909-911
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• 1996

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.126-133
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• 1999

Ultrastructure of the zona radiata and the micropyle of ripe eggs in the rainbow trout (Oncorhynchus mykiss), catfish (Silurus asotus) and loach (Misgurnus anguillicaudatus) were examined by light, scanning and transmission microscopes. The egg micropyle of rainbow trout and catfish consists of a funnel-shaped vestibule and a tapered canal transversing the zona radiata. The micropyle of rainbow trout and catfish showed the similar structure with flat pit and long canal. The micropylar wall showed the clockwise spiral structure in rainbow trout. The micropyle of the loach showed the type with a hollow pit leading into a short canal and the micropylar wall showed the counterclockwise spiral structure. There are numerous and various size pores at the surface area around the opening in every experimented fish. Interconnecting ridges were observed in the unfertilized eggs of every fish.

• Journal of Aquaculture
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• v.12 no.4
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• pp.293-301
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• 1999

This study was conducted to evaluate the possible utilization of 5 different animal protein sources in juvenile rainbow trout, Oncorhynchus mykiss. Meat and bone meal (MBM), feather meal (FM), squid liver powder (SLP), poultry by-product(PBP) and blood meal (BM) were chosen to be the candidate for the possible ingredients for the dietary fish meal replacer in rainbow trout feed. Six different diets were formulated of isonitrogenous and isocaloric basis of $48\textperthousand$ crude protein and 16.7 kJ/g diet: diet 1, $100\textperthousand$ white fish meal (WFM); diet w, $80\textperthousand$ WFM +20% MBM; diet 3, 80% WFM +20% FM; diet 4, 80% WFM+20% SLP; diet 5, 80% SFM+20% PBP; diet 6, 80% WFM +20% BM. As the dietary protein sources, each diet containing 34.7% of animal protein were supplied by WFM with and without MBM, FM, SLP, PBP or BM and approximately 64.2% of plant protein. After one week of conditioning period, fish averaging 2g were divided into six groups and fed one of the experimental diets for 8 weeks. After eight weeks of feeding trials, there were no significant differences in weight gain and feed conversion ratio among groups of fish fed diet 1, 3, 4, 5 and 6(P>0.05). However, weight gain of fish fed diet 2 were significantly lower than those of fish fed diet 1, 3, 4, 5 and 6(P<0.05). These results indicated that FM, SLP, PBP and BM can be used as a dietary fish meal replacer up to 20% in juvenile rainbow trout.