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为提高海捕低值鱼加工利用率,合理利用鱼糜及鱼糜制品加工中的副产物,充分利用鱼类自身内源酶,寻求低值鱼精深加工的低碳高效利用,以梅童鱼(Collichthys lucidus)为研究对象,利用鱼类自身的内源蛋白酶将鱼体内的蛋白质酶解,在自然p H条件下,观察了液料比、自溶温度、时间对梅童鱼蛋白水解的影响,以可溶性蛋白/总蛋白的值为响应值,采用响应面分析优化自溶条件。通过求解回归方程得到的最优自溶条件为:液料比3.4,温度53℃,时间267 min。经过验证,可溶性蛋白/总蛋白的值为18.35%,与回归方程的预测值18.55%相比,相对误差1.1%,说明模型能较好地预测自溶过程中可溶性蛋白/总蛋白的值。在此条件下,测得水解度为15.84%,过0.45μm微滤膜蛋白质量比为9.83%。研究表明,该水解工艺可为生产鱼露、活性肽、氨基酸等提供技术依据。 相似文献
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光照强度和氮营养盐浓度对龙须菜生理代谢的影响 总被引：1，自引：1，他引：0
以龙须菜(Gracilaria lemaneiformis)为材料,以无机氮(NO_3~-︰NH_4~+=2︰1)为氮源配制人工海水,将在低光低氮(L-N-)条件下培养的龙须菜部分给予高光照处理(L+N-),同时另一部分在给予高光照的同时给予更充足的氮源(L+N+),通过测定3种不同处理条件下物质积累、光合色素以及碳氮代谢中的关键酶等多种生理指标,探讨光照强弱与氮源多寡对龙须菜生理代谢的影响。结果表明,在低氮培养时,高光可使藻体可溶性蛋白、含水率、藻红蛋白和叶绿素a的含量下降,而可溶性糖含量上升13.67%;高光培养时,高氮使可溶性蛋白、含水率、藻红蛋白和叶绿素a的含量上升,而可溶性糖含量下降16.3%;相对于低光低氮(L-N-),高光高氮(L+N+)条件培养使藻体中可溶性蛋白和藻红蛋白含量增加,其含水率、叶绿素a和可溶性糖含量并无显著性差异(P0.05)。从上述结果可以看出,补充氮源能够在一定程度上消除高光照对藻体产生的影响,保证藻体基本生理状态不发生变化的情况下积累蛋白(氮源)。同时补充氮源使得谷氨酰胺合成酶(GS)和天庚酮糖-1,7-二磷酸酶(SBPase)的表达均下调,也反映了光合作用所产生的三碳化合物在氮源充足的条件下主要流向了氮循环。而高光照并未对碳氮代谢关键酶的表达产生影响,可能通过直接破坏叶绿素a而影响藻体的光合作用。 相似文献
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食品添加剂对南极大磷虾蛋白自溶的影响 总被引：2，自引：1，他引：1
以氨基态氮、可溶性蛋白质含量和可溶性固形物含量为指标,研究了食品添加剂对南极大磷虾(Euphausia superba)蛋白自溶的影响。结果显示,氯化镁和柠檬酸对南极大磷虾蛋白的自溶有一定的促进作用,两者作用显著的添加量分别为2%和0.2%,结合可溶性蛋白质和可溶性固形物指标,促进作用最显著的为添加0.2%柠檬酸;葡萄糖和氯化钙对南极大磷虾蛋白的自溶影响不大;氯化钾、氯化钠、EDTA-2Na对南极大磷虾蛋白的自溶有一定的抑制作用,氯化钠和EDTA-2Na的抑制作用相近,但优于氯化钾,三者作用显著的添加量分别为2%、4%、0.05%,考虑到可溶性蛋白质含量,抑制作用最显著为添加0.05%EDTA-2Na。 相似文献
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鱼降压肽的酶法制备工艺及其理化性质 总被引：2，自引：0，他引：2
采用高效液相色谱测定降压肽的血管紧张素转化酶抑制活性,对碱性蛋白酶水解草鱼蛋白制备鱼降压肽进行研究。结果表明,碱性蛋白酶水解草鱼蛋白制备鱼降压肽的较佳工艺条件为:pH9.0、温度50℃、酶与底物比48AU.kg-1、水解度34.52%。鱼降压肽成分分析结果显示,鱼降压肽中可溶性氮含量为81.26%,肽含量为72.81%,脂肪含量为0.12%,水分含量为3.54%,灰分含量为9.47%。体积排阻色谱测定鱼降压肽的相对分子质量在124~10581之间,主要集中在124~1062之间;溶解度高效液相测定结果表明,在pH3.0~11.0时鱼降压肽溶解度为96.0%左右,可广泛应用于食品中。 相似文献
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《渔业科学进展》2017,(3)
坚强芽孢杆菌(Bacillus firmus)PC024是一株分离自中国明对虾(Fenneropenaeus chinensis)养殖环境,且能够提高对虾免疫力和抗病力的益生菌。本研究优化其发酵豆粕的工艺条件,单因素优化结果:最佳接种量为2×10~6 CFU/g,最佳料水比为1∶0.8,最佳发酵时间为90 h,最佳发酵温度为37℃。在单因素实验结果的基础上,采用响应面法对4个因素进行了优化,最终确定最佳发酵条件:发酵温度为39.0℃,发酵时间为100 h 18 min,料水比为1∶0.96,接种量为3.84×10~6 CFU/g。经此条件发酵后,发酵产物中的菌浓度可达1.23×10~(10) CFU/g,验证值与预测值相差5.13%,优化模型可靠。豆粕经发酵后发生感官变化,豆粕发酵的得率为(93.89±0.01)%,可溶性蛋白含量由发酵前的(39.16±0.01)%增加到(58.80±4.54)%,豆粕粗蛋白质由发酵前的50.71%增加到55.03%,15种氨基酸的总含量增加到原来的132.30%,增加比例最大的5种为精氨酸(168.60%)、赖氨酸(157.20%)、丝氨酸(152.50%)、苏氨酸(139.04%)和甘氨酸(138.40%)。经SDS-PAGE显示,蛋白大分子得到有效降解。本研究可为益生菌的利用和对虾疾病防控提供新思路。 相似文献
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研究了钙离子浓度对日本沼虾(Macrobrachium nipponense)感光细胞中可溶性Gq蛋白α亚基含量的影响.以暗适应状态日本沼虾的复眼视网膜为材料,分别用高钙溶液、生理溶液、低钙溶液进行孵育,应用SDS-PAGE及免疫印迹技术对其可溶性蛋白粗提取液进行分离和鉴定,并利用Tanon GIS凝胶图像处理系统对蛋白条带的含量进行分析,结果显示:不同钙离子浓度中孵育的日本沼虾感光细胞蛋白的条带数量和分子量大小基本相同.兔抗Gqα多克隆抗体在高钙溶液、生理溶液及低钙溶液处理的日本沼虾感光细胞中均识别了可溶性Gq蛋白α亚基,分子量为42 ku,可溶性Gq蛋白α亚基的含量分别是8.6%、8.4%和7.2%.在暗适应条件下,细胞中可溶性Gq蛋白α亚基的含量与钙离子浓度成正比,这表明钙离子浓度的升高可促进膜结合的Gq蛋白α亚基转化为可溶性的Gq蛋白α亚基. 相似文献
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《畜禽业》2017,(10):1-3
目的:近5年以来,我国雾霾污染十分严重,猪场也同受其害,雾霾中包括菲等有害物质危害猪和养殖人员的健康;而香菇菌分泌的漆酶等可以降解多种有害物质,因此实验研究香菇菌粗酶液对雾霾中菲的作用,为消除雾霾中菲对人和动物的危害提供借鉴。方法:本实验首先采用L_93~4正交实验,研究流速(0.6 mL/min、0.8 mL/min、1.0 mL/min),波长(210 nm、220 nm、254 nm),柱温(25℃、30℃、40℃),有机相甲醇和水相之比(75:25、70:30、85:15)来确定高效液相色谱仪器检测雾霾中的菲的条件参数。然后采用L_93~4正交实验,研究温度(35℃、40℃、30℃),酶处理时间(10h、20h、30h),pH(4.0、4.4、4.8),加入酶的量(5mL、10mL、15mL)对香菇粗酶液降解雾霾中菲的影响。结果:发现最适条件:温度40℃,pH值4.0,处理时间30 h,加入酶的量10 mL;在此条件下菲含量为0.351846±0.047246 ng/m~3,降解前雾霾样品中的菲含量为108.3298 ng/m~3,降解率达到99.68%。结论:可以用香菇菌粗酶液来降解雾霾中的菲,香菇菌粗酶液可以被开发成为有潜力的解毒剂。 相似文献
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Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean 
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下载免费PDF全文 The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna. 相似文献
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Liping Li Rui Wang Wanwen Liang Xi Gan Ting Huang Yan Huang Jian Li Yunliang Shi Honglin Luo Ming Chen 《广西水产科技》2014,(1)
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China. 相似文献
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In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg. 相似文献
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Iciar Martinez Amaya Velasco Ricardo Pérez-Martín Eskil Forås Michiaki Yamashita Carmen G. Sotelo 《Journal Of Aquatic Food Product Technology》2013,22(4):289-297
The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus. 相似文献
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Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation. 相似文献
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Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection 下载免费PDF全文
下载免费PDF全文 G Sharon M Pimenta‐Leibowitz M C L Vilchis N Isakov D Zilberg 《Journal of fish diseases》2015,38(1):67-74
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality). 相似文献
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Qin-Cheng Huang Di‐Gen Qin Bei‐Ping Tan Tao Du Yuan-Zhi Yang Qi-hui Yang Shu‐Yan Chi Xiao-hui Dong 《Aquaculture Research》2020,51(2):816-827
A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg. 相似文献
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William King V David L. Berlinsky Craig V. Sullivan 《Fish physiology and biochemistry》1995,14(6):489-500
Plasma estradiol-17 (E2), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E2 and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E2 and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass. 相似文献