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Trudeau V.L.,University of Ottawa | Martyniuk C.J.,University of New Brunswick | Zhao E.,University of Ottawa | Hu H.,Beijing Fisheries Research Institute | And 3 more authors.
General and Comparative Endocrinology | Year: 2012

Numerous small potentially bioactive peptides are derived from the selective processing of the ~600 amino acid secretogranin II (SgII) precursor, but only the 31-42 amino acid segment termed secretoneurin (SN) is well-conserved from sharks to mammals. Both SNa and SNb paralogs have been identified in some teleosts, likely arising as a result of the specific genome duplication event in this lineage. Only one copy of the putative lamprey SgII (188 amino acids) could be identified which gives rise to a divergent agnathan SN that contains the signature YTPQ-X-LA-X 7-EL sequence typical of the central core of all known SN peptides. In rodent models, SN has regulatory effects on neuroinflammation and neurotransmitter release, and possesses therapeutic potential for the induction of angiogenesis. The wide distribution of SN in neuroendocrine neurons and pituitary cells suggests important endocrine roles. The clearest example of the endocrine action of SN is the stimulatory effects on pituitary luteinizing hormone release from goldfish pituitary and mouse LβT2 gonadotroph cells, indicative of an important role in reproduction. Several lines of evidence suggest that the SN receptor is most likely a G-protein coupled protein. Microarray analysis of SN effects on dispersed goldfish pituitary cells in vitro reveals novel SN actions that include effects on genes involved in notch signaling and the guanylate cyclase pathway. Intracerebroventricular injection of SN increases feeding and locomotory behaviors in goldfish. Given that SgII appeared early in vertebrate evolution, SN is an old peptide with emerging implications as a new multifunctional hormone. © 2011 Elsevier Inc.

Zhang Q.-J.,China Agricultural University | Zhang Q.-J.,Beijing Fisheries Research Institute | Zhou G.-B.,Sichuan Agricultural University | Wang Y.-P.,China Agricultural University | And 2 more authors.
Cryo-Letters | Year: 2012

This study was conducted to investigate the effect of six cryoprotectants (dimethyl sulfoxide (DMSO), glycerol (Gly), methanol (MeOH), ethylene glycol (EG), 1, 2-propylene glycol (PG) and N, N-dimethylformamide (DMF) on the survival of medaka (Oryzias lapites) embryos at low temperatures (O and -5°C). Firstly, the embryos at 8 to 16-cell stages were exposed to different concentrations (1 to 4 mol/L) of DMSO, Gly, MeOH, EG, PG and DMF for 40min at 26°C. After removal of the cryoprotectants (CPAs), the embryo survivals were assessed by their development into live fries following 9 day of culture. The results showed that the higher concentration of the CPA, the lower survival of the embryos; and that the toxicity of the six CPAs to medaka embryos is in the order of PG < MeOH = DMSO < Gly < EG < DMF (P<0.05). Secondly, based on the results obtained above, embryos at 8 to 16-cell stages or other stages were exposed to 2 mol/L of PG, MeOH or DMSO for up to 180 min at 0°C and up to 80 min at -5°C respectively. The 8 to 16-cell embryos treated with MeOH at low temperatures showed highest survival. Thirdly, when embryos at different stages were treated with 2 mol/L of MeOH at -5°C for 60 min, 16-somite stage embryos showed highest survival, followed by 4-somite, neurula, 50% epiboly, blastula, 32-cell and 8 to 16-cell embryos. These results demonstrated that PG had the lowest toxicity to medaka embryos among the six permeable CPAs at 26°C, whereas MeOH showed highest cryoprotective efficiency under chilling conditions and chilling injury decreased gradually with the development of medaka embryos. © CryoLetters.

Luo L.,Beijing Fisheries Research Institute | Wang J.,Chinese Academy of Agricultural Sciences | Pan Q.,University of South China | Xue M.,Chinese Academy of Agricultural Sciences | And 3 more authors.
Aquaculture Research | Year: 2012

Nutrient apparent digestibility coefficients (ADCs) of pet food grade poultry by-product meal (PBM) were determined for black tiger prawn, Penaeus monodon and Pacific white shrimp, Litopenaeus vannamei by the indirect method (reference diet and test diet at 7:3 ratio). Subsequently, an 8-week growth trial was conducted to evaluate the effects of substitution of fishmeal (FM) with PBM in diets of P. monodon (initial weight = 0.21 ± 0.01 g). In the growth trial, six isonitrogenous and isoenergetic diets PBM0, PBM25, PBM50, PBM75, PBM100 and PBMA100, containing a gradient of PBM 0, 88.7, 177.4, 266, 354.7 and 354 g kg-1 to replace 0, 92.5, 185, 277.5, 370 and 370 g kg-1 FM were fed to four replicate groups respectively. The diet PBMA100 was supplemented with DL-Met to be similar to PBM0. The results showed that both P. monodon and L. vannamei had relatively high ADC of crude protein (77.6% and 84.2% respectively) and gross energy (72.8% and 84.0% respectively) for PBM. Litopenaeus vannamei showed significantly higher digestion ability for PBM than P. monodon (P < 0.05). In growth trial, no significant difference in growth performance was observed among shrimp fed the experimental diets. DL-Met supplementation did not improve the growth of P. monodon. PBM is a suitable protein ingredient for P. monodon feeds and can be used up to 354.7 g kg-1 to totally replaced FM. © 2011 Blackwell Publishing Ltd.

Luo L.,Beijing Fisheries Research Institute | Xue M.,Chinese Academy of Agricultural Sciences | Vachot C.,French National Institute for Agricultural Research | Geurden I.,French National Institute for Agricultural Research | Kaushik S.,French National Institute for Agricultural Research
Aquaculture | Year: 2014

This study examined the effect of dietary medium-chain triglycerides supplied by coconut oil on postprandial plasma metabolite profiles in rainbow trout. The fish (initial body weight 71.3 ± 0.3. g, 17. °C) were fed one of four practical diets containing either 5% fish oil (FO low-fat, FL), 15% fish oil (FO high-fat, FH), 5% coconut oil (CO low-fat, CL) or 15% coconut oil (CO high-fat, CH) for 3. weeks. At the end of the trial, the fish were weighed and plasma sampled to determine glucose, non-esterified fatty acids (NEFA), triglyceride (TG), cholesterol, high density lipoprotein-cholesterol (HDL-cholesterol), and myeloperoxidase (MPO) at 3, 6, 9, 12, 15 and 24. h after the last meal. Plasma total ketone bodies (KB) were determined at 6, 12 and 24. h after meal. Blood nitroblue tetrazolium (NBT) tests were also performed in samples withdrawn at 24. h after meal.Plasma glucose was higher in fish fed the low fat level diet than those fed high fat level, and peaked at postprandial 9-12. h. Fish fed CH showed higher plasma TG than CL at 3. h after meal, and there was no significant difference in plasma TG at the other time points. The peak of TG appeared 12. h after the meal. No clear pattern was found for cholesterol and HDL-cholesterol (HDL-C) in any of the groups. However, fish fed diet FH had the highest postprandial plasma HDL-cholesterol level and HDL-C/cholesterol ratio. The peak of NEFA was observed at 12-15. h after meal and plasma NEFA of fish fed CH was the highest. Plasma total KB decreased with postprandial time, and fish of FH groups had higher KB than that of CL group at 6. h. Besides, NBT in fish fed FH was significantly higher than that of CH, but there were no differences in MPO between groups. In summary, time-course changes in plasma profiles related to dietary fat level were as expected whereas those related to dietary fat source were relatively small. © 2013 Elsevier B.V.

Lin X.,Southwest University | Chen W.,Southwest University | Lin S.,Southwest University | Luo L.,Beijing Fisheries Research Institute
Aquaculture Research | Year: 2015

An 8-week feeding trial was conducted to evaluate the effect of dietary cecropin on growth performance, non-specific immunity and disease resistance of hybrid tilapia (Oreochromis niloticus × O. aureus). A basal diet was supplemented with 0 (control), 75, 150 and 225 mg kg-1 cecropin to formulate four experimental diets. The results showed that final body weight and specific growth rate obtained with diet 150 mg kg-1 cecropin were significantly higher (P < 0.05) than that obtained with diets 0 and 75 mg kg-1, whereas there was no difference between 150 and 225 mg kg-1. Feed conversion efficiency was improved by increasing the dietary cecropin content (P < 0.05). However, feeding intake was reduced as dietary cecropin increased. Serum lysozyme, alkaline phosphatase, catalase and superoxide dismutase activity were significantly increased with the increased levels of dietary cecropin (P < 0.05), and reached a maximum at level of 150 mg kg-1 cecropin, then those values no longer increased. Moreover, the dietary cecropin supplementation level also exhibited a decrease in the cumulative mortality rates compared with the controls when challenged with Aeromonas veronii. The results suggested that the dietary supplementation of cecropin could improve the growth, non-specific immunity indicators and resistance of hybrid tilapia against A. veronii. © 2015 John Wiley & Sons Ltd.

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