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911.
The effects of dietary inulin on growth performances,survival and digestive enzyme activities of common carp (Cyprinus carpio) fry
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This study was conducted to investigate the effects of dietary inulin on growth performance, diet utilization, survival rate, carcass composition and digestive enzymes activities (amylase, lipase and protease) of carp (Cyprinus carpio) fry (0.55 ± 0.02 g). After acclimation, fish were allocated into 9 tanks (40 fish per tank) and triplicate fish groups were fed, control diet (0 g) or diets containing 5 g and 10 g inulin kg?1 for 7 weeks. No significant effect on growth performance and diet utilization of fish fed inulin compared with the control group was observed. However, supplementation of inulin significantly increased survival rate and carcass lipid content, while carcass protein content significantly decreased. Dietary inulin had no significant effects on digestive lipase, protease and amylase activities. 相似文献
912.
Measurement of cortisol response is an important tool to asses stress in fisheries research. Radioimmunoassay (RIA) is a common
method for the measure of cortisol in fish. Use of enzyme-linked immunosorbent assays (ELISA) to detect cortisol would eliminate
health hazards, costs of handling radioisotopes, and the short stability time associated with RIA. Enzyme-linked immunosorbent
assays have been used for the determination of cortisol in several fish species. However, the ELISA method of cortisol determination
in fish lacks proper validation testing. We conducted validation procedures for multiple commercial cortisol ELISA kits and
compared the results to RIA. The assays were tested for four species: (1) channel catfish Ictalurus punctatus, (2) largemouth bass Micropterus salmoides, (3) red pacu Piaractus brachypomus, and (4) golden shiners Notemigonus crysoleucas. We evaluated the ELISA methods against RIA, and determined that at least one kit is suitable (accuracy: mean recovery of
spiked samples, 102.8%; reproducibility: interassay coefficient of variation < 10.5% for all species; precision: intra-assay
coefficient of variation < 16.8% for all species; linearity: R
2 > 0.96 for all species) for the measurement of cortisol response in fish and comparative determination of stress. All of
the ELISA assay results varied by more than 10% from the cortisol concentrations detected by the RIA. The high variability
of the kit results indicates that commercial ELISA kits could be utilized for qualitative determination of cortisol in fish,
but should be fully validated in each laboratory for each species before being used for research. 相似文献
913.
Castillo D Higuera G Villa M Middelboe M Dalsgaard I Madsen L Espejo RT 《Journal of fish diseases》2012,35(3):193-201
Flavobacterium psychrophilum causes rainbow trout fry syndrome (RTFS) and cold water disease (CWD) in salmonid aquaculture. We report characterization of F. psychrophilum strains and their bacteriophages isolated in Chilean salmonid aquaculture. Results suggest that under laboratory conditions phages can decrease mortality of salmonids from infection by their F. psychrophilum host strain. Twelve F. psychrophilum isolates were characterized, with DNA restriction patterns showing low diversity between strains despite their being obtained from different salmonid production sites and from different tissues. We isolated 15 bacteriophages able to infect some of the F. psychrophilum isolates and characterized six of them in detail. DNA genome sizes were close to 50 Kbp and corresponded to the Siphoviridae and Podoviridae families. One isolate, 6H, probably contains lipids as an essential virion component, based on its chloroform sensitivity and low buoyant density in CsCl. Each phage isolate rarely infected F. psychrophilum strains other than the strain used for its enrichment and isolation. Some bacteriophages could decrease mortality from intraperitoneal injection of its host strain when added together with the bacteria in a ratio of 10 plaque-forming units per colony-forming unit. While we recognize the artificial laboratory conditions used for these protection assays, this work is the first to demonstrate that phages might be able protect salmonids from RTFS or CWD. 相似文献
914.
Interannual variations in abundance, timing of outmigration from rivers, growth rate and condition of juvenile chum salmon
(Oncorhynchus keta) were studied in the Nemuro Strait (eastern Hokkaido, Japan) during 1999–2002 to establish a possible relationship to zooplankton
abundance. The otolith microstructure of juveniles was examined each year in late June to determine their time and size at
sea entry (i.e., outmigration), and to estimate the early marine growth rates. Salmon outmigration peaked in mid- or late
May, which coincided, in three of the four study years, with the peak release of juveniles into rivers within the study area.
Abundance, growth rate and condition of fish were higher in 2001, when—compared to other years—smaller fish experienced higher
growth rates, coinciding with greater zooplankton abundance for that year. Our results suggest that high zooplankton abundance
positively influenced juvenile chum salmon growth and the condition of the fish during their early marine life despite their
small size at sea entry. 相似文献
915.
To standardize conditions during the final maturation and ovulation of ovarian follicles from Japanese eel, we have developed
a culture system for the production of fertilizable eggs from post-vitellogenic ovarian follicles in vitro. Post-vitellogenic
ovarian follicles were incubated in culture medium supplemented with 17α,20β-dihydroxy-4-pregnen-3-one (DHP) with or without
bovine serum albumin (BSA) to assess the effects of protein concentration. Eggs that ovulated during incubation were fertilized,
and the remaining follicles were incubated in prostaglandin F2α (PGF2α) for a further 3 or 6 h before fertilization. Male eels were injected repeatedly with human chorionic gonadotropin. The quality
of eggs obtained under the different culture conditions was evaluated after artificial fertilization in terms of hatching
success. Hatching rates tended to decrease with increasing concentrations of BSA in the incubation medium in a dose-dependent
manner. The addition of PGF2α drastically increased the number of eggs that ovulated, but the rate of hatching was greatly decreased compared with eggs
obtained earlier by DHP incubation alone. The larvae obtained from artificially fertilized eggs produced in vitro survived
for 14 days without feeding. We conclude that in vitro culture systems thus have a great potential for the acquisition of
good quality eggs under tightly controlled artificial conditions, culminating in the production of eel larvae. 相似文献
916.
Shiwei Xie Lixia Tian Jin Niu Guiying Liang Yongjian Liu 《Fish physiology and biochemistry》2017,43(4):1011-1020
An 8-week feeding trial was conducted to evaluate the effect of N-acetyl cysteine (NAC) and glycine supplementation on growth performance, glutathione (GSH) synthesis, and antioxidative ability of grass carp, Ctenopharyngodon idella. Four practical diets were formulated: control, control + 0.2% NAC, control + 0.5% glycine, and control + 0.2% NAC + 0.5% glycine. Each diet was randomly assigned to quadruplicate groups of 30 fish (approximately 8.8 g). Weight gain and specific growth rate were significantly increased with the supplementation of NAC. Supplementation of NAC plus glycine significantly increased the feed efficiency. Glutathione peroxidase (GPx) and γ-glutamine cysteine synthase (γ-GCS) in plasma were significantly increased with the supplementation of NAC plus glycine. GSH in plasma increased and malondialdehyde (MDA) decreased in fish fed diets supplemented with NAC. Respiratory burst, superoxide dismutase (SOD), and catalase (CAT) activity were not affected by NAC or glycine. These results clearly indicated that NAC improved the growth performance and restored GSH of grass carp, supplemented NAC together with glycine enhanced GSH synthesis, and improved the antioxidative ability of grass carp. 相似文献
917.
An aquabirnavirus (ABV) and a formalin-inactivated betanodavirus [redspotted grouper nervous necrosis virus (RGNNV)] were investigated for their potential to prevent RGNNV-induced viral nervous necrosis (VNN) in the sevenband grouper, Epinephelus septemfasciatus (Thunberg). Three groups of fish were injected intramuscularly with ABV, intraperitoneally with inactivated RGNNV (iRGNNV) or with both ABV and iRGNNV. At 3, 7, 14, 21 and 28 days post-injection (p.i.), fish were challenged by intramuscular injection of RGNNV. Control fish, which received neither ABV nor iRGNNV, showed high mortalities in all RGNNV challenges. Fish that received only ABV exhibited relative percent survival (RPS) of >60 against RGNNV challenges at 3, 7, 14 and 21 days p.i., but not at 28 days p.i., while fish that received only iRGNNV showed significantly higher protection against RGNNV challenges only at 21 and 28 days p.i. In contrast, fish that received both ABV and iRGNNV showed 60 or higher RPS against all RGNNV challenges. Fish inoculated with iRGNNV with or without ABV exhibited similar high titres of neutralizing antibodies to RGNNV at 14, 21 and 28 days p.i. These results indicate that combined inoculation with iRGNNV and ABV conferred both rapid non-specific and delayed specific protection against VNN. 相似文献
918.
Salmon testes meal as a functional feed additive in fish meal and plant protein‐based diets for rainbow trout (Oncorhynchus mykiss Walbaum) and Nile tilapia (Oreochromis niloticus L.) fry
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Kyeong‐Jun Lee Samad Rahimnejad Madison S Powell Frederick T Barrows Scott Smiley Peter J Bechtel Ronald W Hardy 《Aquaculture Research》2015,46(7):1590-1596
Fishery processing by‐products are a large resource from which to produce fishmeal and other products for a variety of uses. In this study, testes meal (TM) produced from pink salmon processing by‐product was evaluated as a functional ingredient in aquafeeds. Nile tilapia and rainbow trout fry were fed five isonitrogenous and isoenergetic experimental diets for 4 and 9 weeks respectively. Two diets were fishmeal‐based (FM) and three were plant protein‐based (PP). Salmon TM was added to the FM and PP diets at 7% to replace 20% of fishmeal protein (FMTM and PPTM respectively). An additional control diet was prepared in which fishmeal was added to the PP diet to supply an equivalent amount of protein as supplied by TM (PPFM). Inclusion of TM in both the FM‐ and PP‐based diets resulted in higher final body weights, although differences were only significant between rainbow trout fed FM or FMTM diets. Similar differences were calculated for other indices of fish performance, e.g. specific growth rate, feed conversion ratio, protein efficiency ratio and protein retention efficiency. Feed intake was significantly higher for fish fed FMTM compared with FM in rainbow trout. For tilapia, final weights were numerically higher, but not significantly different for fish fed diets containing TM compared with non‐TM diets (FM vs. FMTM; PP vs. PPTM). Performance of trout or tilapia fed the PPFM diet did not increase compared with the PP diet. The results indicate that TM addition to both FM and PP diets increased feed intake and also increased metabolic efficiency, demonstrating that TM can be a functional ingredient in aquafeeds. 相似文献
919.
D.S. Wang B. Senthilkumaran T. Kobayashi H. Kajiura-Kobayashi M. Matsuda M. Yoshikuni Y. Nagahama 《Fish physiology and biochemistry》2003,28(1-4):225-226
Tilapia riboflavin-binding protein (RfBP) cDNA was isolated by library screening. Even though it shows only 31~35% similarity to the reported RfBPs, tilapia RfBP is conserved in amino acid residues that are known to be essential for its protein function. The exclusive expression of RfBP in the brain-pituitary-gonadal axis, as revealed by both RT-PCR and Northern blot, suggested a possible role for RfBP in fish reproduction. 相似文献
920.
Effects of mangrove deforestation on fish assemblage at Pak Phanang Bay,southern Thailand 总被引:2,自引:0,他引:2
Tatsuya Shinnaka Mitsuhiko Sano Kou Ikejima Prasert Tongnunui Masahiro Horinouchi Hisashi Kurokura 《Fisheries Science》2007,73(4):862-870
Daytime sampling using a seine net was conducted at Pak Phanang Bay (Nakhon Si Thammarat Province, Thailand) in February and
July 2006, to determine differences in fish assemblage structures between a mangrove site and an adjacent site completely
cleared of mangroves. The overall numbers of fish species and individuals were significantly higher at the mangrove site than
the cleared site in both months. Although benthic crustacean feeders showed more species and individual numbers at the mangrove
site in both months, the opposite was found for zooplankton feeders. A cluster analysis, based on the abundance of each species,
demonstrated that the fish assemblage structures were distinctly different between the two sites. In addition, significant
differences in length frequency distributions for each of the four most abundant species were found between the sites in February
and/or July. Small individuals of Scatophagus argus, Ambassis nalua, and Tetraodon nigroviridis were more common at the mangrove site, and of Chelon subviridis at the cleared site. These results suggest that mangrove deforestation exerts marked effects on fish assemblages. 相似文献