甲基盐霉素对鲤白细胞吞噬活性和溶菌酶活力的影响

选用60 g左右健康正常的鲤540尾,随机平均分为6组,每组设3个重复。试验设6种处理,即基础饲料中分别添加甲基盐霉素0(对照组)、10、20、40、80、160 mg/kg。研究了甲基盐霉素对鲤白细胞吞噬活性和溶菌酶活性的影响。试验结果表明,饲料中添加10 mg/kg甲基盐霉素对鲤白细胞吞噬活性和溶菌酶活性影响不显著,而添加20~160 mg/kg甲基盐霉素对鲤白细胞吞噬活性和溶菌酶活性有一个从促进到抑制的转变,剂量越高,这个转变越快,并且随饲喂时间的延长,其抑制作用越来越强。     

Assessing the Antioxidant Activity of the Ultrafiltration Fractions From Silver Carp Protein Hydrolysate by Different Antioxidant Methods

Silver carp protein hydrolysate (SH) was fractionated by 5- and 1-kDa cutoff ultrafiltration (UF) membrane, and three ultrafiltrates were obtained: SHI (>5 kDa), SHII (1–5 kDa), and SHIII (<1 kDa) which were screened for antioxidant activity by five in vitro assays. The SHIII showed higher 2, 2-azobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and oxygen radical absorbance capacity (ORAC) values, inhibiting effects for liposome oxidation induced by Fe³⁺/V_C. The SHII showed higher ferric reducing power (FRAP) and inhibiting effects for liposome oxidation induced by 2, 2′-azobis (2-methylpropionamidine) dihydrochloride (AAPH). However, the SHI showed the highest 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging activity. Therefore, the antioxidant activity of silver carp protein hydrolysates was mainly associated with their molecular weight distribution, and the antioxidant assays used to test different samples gave comparable results.     

Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activities of Protein Hydrolysates Prepared from Threadfin Bream (Nemipterus spp.) Surimi By-products

Solid wastes from threadfin bream (Nemipterus spp.) surimi production composed of head and frame were hydrolyzed by various commercial proteases (Alcalase, Flavourzyme, Neutrase, Protamex, papain, and pepsin) to produce protein hydrolysates with bioactive properties. An Alcalase-hydrolyzed sample at 24.4% degree of hydrolysis (DH) displayed the highest antioxidant activity based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP) assay, and potassium ferricyanide method. In addition, it showed an inhibitory activity toward angiotensin-converting enzyme (ACE) of 25.5%. Antioxidant activity of threadfin bream by-product hydrolysates increased with hydrolysis time and reached the highest DPPH activity after 6 h, while that hydrolyzed for 3 h showed the highest reducing power based on FRAP and potassium ferricyanide assays. In addition, ACE inhibitory activity was found to be at an optimum after 3 h of hydrolysis. The hydrolysates (1 mg/mL) also retarded oxidation of a linoleic acid emulsion system to a similar extent as 0.1 mg/mL 3-tert-butyl-4-hydroxy anisole (BHA), indicating a potential use in the food system. Protein hydrolysates from threadfin bream surimi by-products could be tailor-made to possess both antioxidant and ACE inhibitory activity through controlling DH of Alcalase-catalyzed reactions.     

Effect of Different Thawing Methods and Multiple Freeze-Thaw Cycles on the Quality of Common Carp (Cyprinus carpio)

The effect of different thawing methods—running water, microwave, slack water (25°C), air (25°C), and refrigerator (4°C)—and multiple freeze-thaw cycles (0, 1, 3, and 5) on the quality of common carp were investigated. Microwave thawing showed the lowest score for sensory assessment and the highest cooking loss (p < 0.05), while 4°C refrigerator thawing showed less thawing loss and cooking loss but required the longest thawing time. Ca²⁺-ATPase activity and sulfhydryl content of air thawing were lower (p < 0.05), while no significant differences were observed among other thawing methods. Water loss and the thiobarbituric acid reactive substances (TBARS) value increased (p < 0.05) when freeze-thaw cycles increased. The sensory scores and hardness decreased significantly when the freeze-thaw cycles increased (p < 0.05). A significant decrease (p < 0.05) was observed in salt-extractable protein content after five freeze-thaw cycles. Different thawing methods affected the quality of common carp. Frozen common carp subjected to freeze-thaw cycles resulted in accelerated lipid and protein oxidation and caused mechanical damage to muscle tissues.     

Evaluation of Plasticizing and Antioxidant Properties of Silver Carp Protein Hydrolysates in Fish Gelatin Film

Physico-mechanical and antioxidant properties of glycerol plasticized fish gelatin films were investigated at different levels of fish protein hydrolysates (FPH) from silver carp muscle (5, 10, 15, and 20 g FPH/100 g gelatin). The films supplemented with FPH, especially at higher concentration showed significant increase in 2, 2-diphenyl-1-picrylhydrazyl (DPPH), 2, 20-azinobis-(3-ethylbenzothiazoline-6-sulfnic acid) (ABTS) radical scavenging, and ferric reducing antioxidant power (FRAP), elongation at break, difference of color, water vapor permeability and opacity, while tensile strength, elastic modulus, L*, b*, and contact angle decreased markedly (p < 0.05). However, no significant differences were observed for a* and solubility of all samples (p > 0.05). Films prepared using 20% FPH had lower glass transition temperature and more homogeneous structure, compared with control film. Also, Fourier transform infrared (FTIR) spectroscopy confirmed the increase of free groups of hydrolysates and lower interaction between chains of film incorporated with the highest content of FPH. Thus, these results indicate that FPH enhanced the antioxidant activities and affected some characteristics due to less interaction between gelatin and FPH.     

黄河鲤肾脏的显微和亚显微结构观察

应用常规解剖学和组织学方法在光镜和电镜下观察成体黄河鲤肾脏的显微和亚显微结构.试验结果显示,黄河鲤的肾脏包括头肾和中肾两部分.头肾实质中没有肾单位,主要由造血组织和淋巴组织构成,可观察到黑色素巨噬细胞中心和甲状腺滤泡;中肾实质中包含有肾小体、肾小管和拟淋巴组织,肾小体由鲍曼氏囊和与其相接触的血管球组成.肾小管由颈段、第...     

Characterization and Cryoprotection of Invasive Silver Carp (Hypophthalmicthys molitrix) Protein Hydrolysates

ABSTRACT

Silver carp (Hypophthalmicthys molitrix) is regarded as an invasive, underutilized freshwater fish causing environmental and economic complications along the U.S. Mississippi River System. In this study, silver carp protein hydrolysates (FPH) were obtained from 30, 60, 90, 120, and 240 min hydrolysis with Protamex®. Amino acid composition showed polar amino acids, including Asp and Glu, and freed hydrophobic residues in FPH-90 and FPH-240. Protein surface hydrophobicity of FPH increased with increasing degree of hydrolysis. Cryoprotection was evaluated using a muscle (mince) food system with 6% FPH (w/w) from each hydrolysis time condition, an untreated mince (CTRL), and 8% (w/w) 1:1 sucrose-sorbitol (SUSO), respectively. After six freeze-thaw cycles (D7), all FPH treatments had lower (p < 0.05) expressible moisture, indicating strong water-holding capacity by the FPH. FPH formulations also imparted antifreeze activity equal to or better than SUSO, with the FPH-90 exhibiting higher (p < 0.05) proportion (43.9%) of unfrozen water at D7. Results from this study provide preliminary evidence for development of effective cryoprotectants using an underutilized, invasive fish species that can be exploited for environmental and economic gain in the form of value-added ingredients and further provide opportunities to understand the fundamental physicochemical properties governing cryoprotection of FPH in a frozen mince system.     

鲤低氧适应性状的全基因组关联分析

低氧适应是水产养殖物种的重要性状,筛选用于改良低氧适应性状的分子标记及候选基因有助于鱼类耐低氧品种选育.在数量性状和质量性状的遗传研究中,全基因组关联分析(GWAS)广泛应用于性状相关标记和基因的发掘.本研究对鲤(Cyprinus carpio)养殖群体开展了低氧胁迫实验,选取了低氧敏感和低氧耐受的极端性状个体作为研究...     

鲤耐低温候选基因CcSCD全长cDNA的克隆及功能预测

硬酯酰辅酶A脱氢酶(Stearoyl-CoA Desaturase,SCD)是参与脂肪酸脱氢反应的限速酶和关键酶,此酶编码基因SCD对增加膜磷脂的不饱和脂肪酸成分,提高细胞膜在低温下的流动性发挥重要作用,可能是抗寒过程中的关键基因成员。本研究采用cDNA末端快速扩增技术(Rapid Amplifications of cDNAEnds,RACE)克隆了鲤(Cyprinus carpio)脑组织CcSCD基因的全长cDNA序列,采用实时荧光定量PCR技术检测该基因在低温(6℃)和常温(23℃)条件下的转录表达差异,对其蛋白编码序列的结构和功能进行了预测分析。结果显示,CcSCD基因cDNA全长2618bp,包含一个由324个氨基酸残基组成的长度为975bp的阅读框(ORF);蛋白分子进化树显示鲤的SCD和草鱼(Ctenopharyngodon idella)的SCD蛋白同源性最高,相似性达88%;实时荧光定量结果表明,低温刺激下(6℃),CcSCD基因表达水平是常温条件下(23℃)的13.9倍,差异非常显著(P0.01)。本研究旨在为今后构建表达载体,通过遗传操作等研究手段鉴定其抗寒功能奠定基础。     

Investigation on protective effect of recombinant protein (OmpTS) of Aeromonas hydrophila in Common carp (Cyprinus carpio)

The outer membrane protein of Aeromonas hydrophila is a potential candidate for vaccine development. In this study, after cloning and expression of ompTS, 270 common carp, weighing 44 ± 5.7 g divided into five groups, were injected intraperitoneally twice with 3‐week intervals. Groups included the following: PBS, PBS plus Freund's adjuvant, recombinant protein, recombinant protein plus Freund's adjuvant and 20 fish as negative control. Two weeks after the second injection, 30 fish of each group were challenged with a dose of 2 × LD₅₀ of Aeromonas hydrophila and RPS was measured. The antibody level was measured using ELISA test. The protection of recombinant protein in the immunized fish with and without adjuvant, respectively, was about 82.61% and 78.26% (the protection of recombinant protein electroeluted from an SDS–PAGE with and without adjuvant, respectively, was about 78.62% and 69.57%). The average of antibody level in recombinant protein with and without adjuvant was significantly higher than the PBS group (p < .05). The ability of recombinant ompTS to increase the antibody level and to protect the fish from challenge by A. hydrophila demonstrated that recombinant ompTS protein injection can be used to immunize common carp against A. hydrophila infection.     

滇池鲤4种年龄鉴定材料的比较

为确定鉴定滇池鲤（Cyprinus carpio）年龄的适宜材料,对4种年龄鉴定材料（耳石、鳞片、胸鳍条和鳃盖骨）的形态和年轮标志进行了描述,并对这4种钙化组织鉴定鲤年龄的一致性进行了探讨。2013年5、6、8-11月以及2014年3-7月,使用拖网采集云南滇池鲤584尾,体长范围7.5~50.5 cm,体重范围17.2~3 211.3 g。其中耳石采集于584尾样本,鳃盖骨和鳞片分别采集于276尾样本,胸鳍条采集于274尾样本。微耳石磨片轮纹清晰,在反射光下呈明暗相间的条纹,年龄标志明显。同一鉴定者2次年龄读数的吻合率,微耳石磨片轮最高（88.0%),鳞片次之(84.1%),胸鳍条和鳃盖骨则分别为73.7%和72.1%。2次读龄的平均误差百分比,微耳石磨片和鳞片较小,分别为2.6%和2.9%;胸鳍条和鳃盖骨较高,分别为4.7%和5.9%。以微耳石磨片年龄读数为基准,鳞片年龄读数与其吻合率最高(77.5%),平均变异系数最低(6.14%);鳃盖骨和胸鳍条与其吻合率分别为61.9%和56.2%,平均变异系数均超过12%。综合分析认为,耳石是滇池鲤年龄鉴定的最佳材料,鉴定4龄以下个体年龄时可使用鳞片,鳃盖骨和胸鳍条则不适于滇池鲤的年龄鉴定。     

Properties of Fish Sausages Containing Common Carp (Cyprinus carpio) Roe Oil and Defatted Roe Protein Hydrolysate during Refrigerated Storage

Influence of emulsified or non-emulsified common carp roe oil (CRO) and carp defatted roe hydrolysate (CDRH) on properties of crucian carp (Carassius auratus) sausages was determined during 30-day storage at 4°C. Sausages containing CRO and CDRH were lighter and had better textural properties including hardness, gumminess, and chewiness. These textural attributes were significantly higher in the sample prepared with pre-emulsified CRO and 7 g/100 g CDRH (p < 0.05). The sausages fortified with CDRH also presented better microstructure, as evidenced by fewer voids and smaller oil droplets. When incorporated at 7 g/100 g, CDRH could significantly reduce microbial spoilage in sausages in terms of the total viable count and the psychrophilic bacterial count (p < 0.05); however, pre-emulsification had no significant effect on antibacterial activity of hydrolysate in the samples (p > 0.05). Sausages with pre-emulsified roe oil and 7 g/100 g hydrolysate were more resistant against lipid oxidation and had a higher level of polyunsaturated fatty acids, especially docosahexaenoic acid and eicosapentaenoic acid after 30 days of storage at 4°C. Furthermore, the sausages with pre-emulsified CRO and 7 g/100 g CDRH exhibited better organoleptic properties at day 30.     

丰产鲫及其双亲肌蛋白和同工酶的比较研究

采用7 5%聚丙烯酰胺垂直板电泳研究了丰产鲫及其母本彭泽鲫和父本海鲤的肌肉蛋白以及心、肝、肾、脑、眼等五种组织的乳酸脱氢酶(LDH)、苹果酸脱氢酶(MDH)。结果发现:丰产鲫的肌肉蛋白和同工酶的电泳图谱与母本彭泽鲫相同而与父本海鲤显著不同,因而认为丰产鲫是彭泽鲫雌核发育的产物,父本基因对子代成体同工酶表型基本无影响。     

Common Kilka Hydrolysis: Investigation of Functional and In Vitro Antioxidant Properties of Hydrolysates Obtained by Kiwifruit and Ginger Proteases

The functional and in vitro antioxidant properties of common kilka fish protein hydrolysates with different degree of hydrolysis (DH) obtained by kiwifruit protease (KP) and ginger protease (GP) were evaluated. The electrophoretic patterns of hydrolysates showed the presence of one major band in different DHs with a molecular weight of less than 25 kDa. Protein solubility was positively correlated with DH, and the solubility of KP and GP hydrolysates (HKP and HGP, respectively) at 15% DH was higher than other DHs (p ≤ 0.05). Higher emulsifying and foaming properties were observed in HKP over a pH range of 2–10 (p ≤ 0.05), and in vitro antioxidant activity was higher in HKP at 15% DH as seen from 2,2-diphenyl-1-picrylhydrazyl radical scavenging and ferric-reducing power. Thus, the results reveal that DH and enzyme type affects functional properties and antioxidant activity of the hydrolysates.     

Improvement of Antioxidant Activity of Grass Carp (Ctenopharyngodon idella) Protein Hydrolysate by Washing and Membrane Removal Pretreatments and Ultrasonic Treatment

To improve the antioxidant activity of grass carp hydrolysate, washing and membrane removal pretreatments and ultrasonic treatment were applied in this study. Various pretreatment methods (washing methods and membrane removal methods) for removing the prooxidants and phospholipid in minced fish were evaluated. The effects of ultrasonic treatment prior to enzyme hydrolysis on the antioxidant activities of minced carp hydrolysate were investigated. The minced carp subjected to washing with 0.4% NaCl solution and subsequent membrane removal with CaCl₂ and citric acid solution had the lowest content of prooxidants and phospholipid remaining in the minced fish. The hydrolysate produced from washing/membrane removal pretreated carp with ultrasonic treatment for 20 min had the highest ferric reducing antioxidant power and scavenging activities against 1,1-diphenyl-2-picrylhydrazyl and 2,2?-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radicals. This suggested that the combination approach of washing/membrane removal pretreatment and ultrasonic treatment could improve the antioxidant activity of carp hydrolysate, and this hydrolysate could be a potential antioxidant ingredient for functional foods.     

饲料蛋白水平对鲤幼鱼肝功能和抗氧化能力的影响

研究了不同蛋白水平饲料对鲤(Cyprinus carpio)幼鱼肝功能和抗氧化能力的影响。选用体质量为(10±1.2)g的健康鲤幼鱼,随机分为5组,每组设3个重复,每个重复35尾鱼。放养在15个规格相同的白色水箱中,分别投喂蛋白水平为30%、30.5%、31%、31.5%和32%的饲料(分别记作Diet 1、Diet 2、Diet 3、Diet 4和Diet5),饲养实验时间为8周,每隔4周对相关生理生化指标进行测定。结果表明,养殖第4和第8周时,31%蛋白水平组血清和肝胰脏的谷丙转氨酶(ALT)和谷草转氨酶(AST)活性均显著降低(P0.05);血清、肝胰脏和肾脏中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和溶菌酶(LZM)活性升高(P0.05),丙二醛(MDA)浓度显著降低(P0.05)。根据实验结果,从饲料配制的成本考虑,31%蛋白水平饲料能够达到维持鲤幼鱼机体正常的抗氧化能力以及保护肝功能的营养需求。     

The Use of Natural Carotenoids and Growth Performance,Skin Pigmentation,and Immune Response in Fancy Carp (Cyprinus carpio)

Fancy carp were fed seven dietary treatments with natural pigment sources (tea, mulberry, cassava) at a specific rate to achieve a total carotenoid (TC) concentration in the diet of 25 mg/kg. Growth performance among treatments was not significantly different (p ≥ 0.05). TC and skin redness (a*) of fish fed tea leaves was higher than the other treatments (p ≤ 0.05). Fish fed with tea extract and cassava leaves had higher serum astaxanthin concentrations than the other groups (p ≤ 0.05). This group also retained serum astaxanthin and red color better than other groups two weeks post treatment (p ≤ 0.05). Phagocytic activity was significantly greater in fish fed carotenoid supplements compared with the control group (P ≤ 0.05). Therefore, dietary supplementation with 25 mg/kg tea leaves is sufficient to obtain good coloration in fancy carp as well as enhance immunity.     

Study on the adaptability of common carp (Cyprinus carpio) to diets from the perspective of digestion and absorption

As an ecologically sustainable aquaculture mode, the rice‐fish approach has been paid more attention in recent years. In rice paddies, there are plant and animal diet items available to fish, but it is not clear how common carp adapt to different diets. In view of this, common carp (initial weight 492.6 ± 30 g, n = 270) were randomly divided into three groups and fed with earthworms (group A), earthworms + duckweed (group M) and duckweed (group P) respectively. After 8 weeks under these feeding regimes, the intestinal digestive enzymes activities were assayed, and intestinal tissue sections stained with HE and AB‐PAS were used to observe the morphology. The results showed that the activities of trypsin and lipase were highest in group A, followed by group M and group P. Group A had greater intestinal fold height, fold width and fold absorption area than the other groups (p < .05), especially in the foregut. Meanwhile, the total number of mucous cells was largest in group P, followed by the groups M and A. Totally, activities and distributions of digestive enzymes, fold height, fold width, fold absorption area and number and distribution of mucous cells of common carp were affected by the type of diet. Based on these results, it was found that common carp has strong adaptability to diets, and it was speculated that the majority of digestion and absorption of protein was concentrated in the foregut, while for starch and cellulose, it was spread out along the whole intestine.     

饲料中添加低聚木糖对鲤鱼免疫力和生长性能的影响

为探究不同质量浓度的低聚木糖调控鲤鱼免疫力及生长性能的机理,以450尾平均体质量（4．93±0．03）g的健康鲤鱼为对象,研究饲料中添加低聚木糖对鲤鱼生长性能和免疫指标的影响。以不加低聚木糖的基础饲料为对照组,试验组为分别在基础饲料中添加0．1％低聚木糖组、0．2％低聚木糖组、0．4％低聚木糖组和0．6％低聚木糖组。试验结果表明,低聚木糖可提高鲤鱼血清溶菌酶活性,但对补体旁路途径溶血活性无影响,0．6％低聚木糖组的血清溶菌酶活性显著高于对照组（P＜0．05）。对于头肾的5种免疫相关基因,低聚木糖可上调白细胞介素-1β和白细胞介素-10的基因表达,下调诱导型一氧化氮合酶和肿瘤坏死因子-α的基因表达,而对转化生长因子-β的基因表达无影响。与对照组相比,0．2％低聚木糖组、0．6％低聚木糖组的白细胞介素-1β与0．2％低聚木糖组的白细胞介素-10表达量均显著升高,所有试验组的诱导型一氧化氮合酶和肿瘤坏死因子-α的表达量均显著下降（P＜0．05）。生长性能试验结果显示,试验组鲤鱼的生长性能指标均高于对照组,其中0．6％低聚木糖组与对照组差异显著（P＜0．05）。     

Investigation of fat content in market common carp (Cyprinus carpio) flesh during the growing season

Effects of supplemental feeding with cereals (rye, triticale, maize and the unsupplemental control group) on fat content in flesh of 3‐year‐old common carp (Cyprinus carpio) were the subject of study carried out at four ponds (Czech Republic, Central Europe) during the growing season. The main result was that supplemental feeding with cereals to the same energetic level was associated with varying growth and fat content in the flesh of common carp. At the end of the experiment, the stock of fish supplementally fed with maize was found to have the highest fat content (112.7 ± 15.6 g kg^?1), while the lowest value of fat content was found in the control group (56.8 ± 9.4 g kg^?1). The carps supplementally fed with rye were found to have a higher fat content (90.1 ± 19.0) than those supplementally fed with triticale (84.3 ± 15.7 g kg^?1). Established average fat content values (except for maize) were at the level that indicate a high sensory quality of carp flesh during the whole growing season.