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1.
电子鼻在对虾新鲜度评价中的应用   总被引:3,自引:0,他引:3       下载免费PDF全文
以凡纳滨对虾Litopenaeus vanmamei为实验对象,研究电子鼻对不同保藏时间的凡纳滨对虾虾头和虾肉的气味响应,并与感官指标、挥发性盐基氮(TVB-N)和菌落总数进行对比分析,建立一种基于电子鼻技术的对虾新鲜度评价方法.结果表明,随着保藏时间的延长,对虾的鲜度和气味发生变化;电子鼻能将不同保藏时间的对虾区分开来,而且与感官评定、TVB-N和菌落总数检测结果一致.负荷加载分析(Loadings)显示,不同传感器对主成分的贡献率不同;采用线性判别分析(LDA)所得的总贡献率高于主成分分析(PCA)所得的总贡献率.电子鼻对虾头和虾肉的气味均有较好的响应,因此虾头和虾肉都可以用于电子鼻评价对虾的新鲜度.  相似文献   

2.
研究了饲料铜离子含量对亚硝酸盐胁迫下斑节对虾(Penaeus monodon)血细胞参数的影响。向斑节对虾投喂不同铜离子添加量(0,10,25,40,55和110 mg/kg)的饲料8周后,进行24 h 的20 mg/L亚硝酸氮胁迫,取样测定对虾的血细胞总数(THC)、血细胞活性氧(ROS)含量和血细胞凋亡率。结果显示,经亚硝酸盐胁迫后,25-55 mg/kg饲料组对虾能保持较高的THC,以及较低血细胞ROS含量和凋亡率;110 mg/kg饲料组对虾的THC最低,血细胞ROS含量和凋亡率均最高。这些结果表明饲料中添加25-55 mg/kg的铜离子能有效降低亚硝酸盐胁迫对血细胞造成的氧化损害,但过量添加(110 mg/kg)反而对血细胞造成更为严重的损害。  相似文献   

3.
对虾免疫机能研究概况   总被引:16,自引:0,他引:16  
陈国福 《水产学报》2004,28(2):209-215
Shrimp farming is an important source of revenue and employment in many developing countries.However, infectious diseases have adversely affected the profitability of shrimp industry. For this reason, disease prevention is a priority and shrimp immunology has become a crucial research area of this field. In this paper, the current importance and problems of shrimp-culture were described and the research advances in shrimp immunological defence mechanisms were summarized. The immunological tools are powerful and useful to evaluate the health state of the shrimp. The immunologies of shrimp mainly consist of cellular immunity and humoral immunity. In regard to cellular parameters, they are composed of haemocyte count (THC), differential haemocyte count (DHC) and reactive oxygen intermediates (ROIs). The immunity ceils exert their defence functions through phagocytizing, enveloping, etc, and the changes of THC and DHC are related to health state of shrimp. The ROIs generated during post phagocytic event which maybe an important marker to evaluate the immunological capability and phenoloxidase activity have been considered as a potential marker which is relevant to the health of the shrimp too. Concerning humoral parameters, prophenoloxidase (ProPO) and phenoloxidase,antimicrobial peptides and proteins, hemagglutinin and plasma proteins were described. The determining methods of immunity parameters were discussed. The response of shrimp to pathogens such as bacteria, virus, etc. and environmental factors such as DO, pH, etc, were also reviewed. It is well-known that the immune responses induced by immunizing crustacean or shrimp are mainly the non-specific immune responses. The potential of immunological parameters, including the changes of THC and DHC, the production of ROIs, phenoloxidase (PO) activity, antibacterial activity of plasma, and so on, to appraise the healthy state of shrimp were partly discussed. The future directions for the evaluation of the immunological capability of shrimp were proposed.  相似文献   

4.
张成松 《水产学报》2004,28(5):535-540
以热休克诱导获得中国对虾三倍体,通过口服或注射的方式对二倍体和三倍体中国对虾进行了白斑综合征病毒(WSSV)和鳗弧菌感染实验,研究了病原感染前后二倍体和三倍体中国对虾血液学的变化并首次报道了三倍体中国对虾血细胞的组成。实验结果表明:三倍体和二倍体中国对虾均对WSSV敏感,三倍体未显示出明显的抗性。WSSV感染4d后,对虾外周循环系统的血细胞数量明显减少,三倍体和二倍体对虾血细胞数量均降为对照组的10%左右。对虾血细胞组成发生变化,大颗粒细胞明显减少,小颗粒细胞相应增加,而透明细胞所占比例基本不变;大颗粒细胞和小颗粒细胞内颗粒物质均有所减少,出现空泡或细胞外突起等异常结构。注射鳗弧菌感染后两种对虾的血细胞数量均有所减少,血细胞数量的减少与弧菌的注射量呈正相关关系:三倍体中国对虾血细胞组成与二倍体相似,但其密度仅为二倍体的40%左右:本研究结果为三倍体对虾抗逆特性的研究提供了一定依据和参考。  相似文献   

5.
Several male Penucus stylirostris were selected from a 3 ha commercial earthen pond and were individually evaluated for reproductive performance. Indicators measured were compound spermatophore weight, sperm count, and sperm abnormalities.
It was found that spermatophore quality was significantly better for 30–40 g shrimp than for 20–30 g shrimp ( P < 0.05). The higher frequency of abnormalities measured in younger males and the inverse relationship between abnormalities and sperm count indicate that the vas deferens could be the tissue responsible for producing highly abnormal immature semen. It is proposed that male maturation has at least three independently controlled levels of organization: testes maturation, vas deferens maturation, and spermatophore synthesis.
The individual evaluation showed that each male followed a particular response in reproductive quality. Changes in spermatophore weight were not an indicator of sperm density within spermatophores.
Male reproductive tract degenerative syndrome (MRTDS) and male reproductive system melanization (MRSM) did not develop in any shrimp during these experiments.  相似文献   

6.
采用微波—红外联合加热技术对凡纳滨对虾进行处理,探讨联合加热条件对对虾品质的影响,为对虾制品的研发奠定理论基础。研究分析对虾在微波—红外加热过程中中心温度的变化,及不同加热条件下虾仁的重量损失率、颜色、质构等品质变化规律。结果显示,在相同微波功率下,红外温度越低,重量损失率越大。在127、179°C红外温度条件下,硬度在200 W时最大,然后随微波功率的增大而下降,1000 W时达到最低值;在75°C下,硬度在400 W时最大。3种红外温度对弹性的影响不显著,当微波功率为400 W时,虾仁的弹性最大,微波功率提高至800 W时,虾仁的弹性明显下降,而弹性在800和1000 W间没有显著差异。在相同微波功率条件下,红外温度75°C时的黏附性与127和179°C时的显著不同。咀嚼性、内聚性在200 W时呈最大,随微波功率增大,并无显著变化。在色差方面,L*、a*、b*和ΔE与红外温度呈负相关。以上结果为联合加热技术在对虾加工中的应用奠定了一定基础。  相似文献   

7.
通过对流式细胞术(FCM)检测虾类血细胞总数(THC)的条件和方法进行优化,为虾类血细胞学研究提供快捷、准确的测定方法。2012年7-9月,应用SYBR Green I作为荧光染料标记完整血细胞,设置3个不同染料浓度(1×、10×和100×),测定不同孵育时间下染色细胞比例的变化。结果显示,染料终浓度为10×时染色效果最佳,其最佳孵育时间为60 min;应用建立的FCM方法和显微计数方法测定10尾凡纳滨对虾(Litopenaeus vannamei)的THC,平均值分别为(16.68±1.57)×106个/m L和(15.09±1.76)×106个/m L,2种方法测定结果的相关性极显著(R2=0.8064,P<0.01)。凡纳滨对虾经不同浓度(0.5 mg/L和5.0 mg/L)的Cd2+胁迫,利用建立的FCM方法测定Cd2+胁迫下对虾THC的变化。结果显示,0.5 mg/L和5.0 mg/L Cd2+胁迫下,对虾THC随着胁迫时间的延长不断下降,胁迫48 h时分别下降至对照组的78.7%和64.7%,可见Cd2+胁迫对虾类血细胞产生毒性,抑制了血细胞活性,表明该方法适用于虾类的血细胞学研究。  相似文献   

8.
研究采用南美白对虾塑料大棚保温三级淡化暂养技术等措施,实现南美白对虾池塘双茬淡化养殖。养成期间水质情况良好,水温平均(26±3)℃,pH值约8.5左右,溶氧量5.6m叽以上,氧氮约0.20mg/L,亚硝酸氮0.02m班左右,每667m^2养殖产量达426.7kg,养殖效益高达4186.7元。结果表明,采用南美白对虾双茬淡化养殖技术,延长了对虾生长期,提高了池塘利用率和经济效益,具有较好的推广价值.  相似文献   

9.
硫化物是水产养殖过程中常见的水体污染物之一。为探讨水体硫化物胁迫对虾类血细胞的毒性影响,以不同浓度(0.5 mg/L,2.0 mg/L)的硫化物对凡纳滨对虾(Litopenaeus vannamei)进行胁迫,于胁迫后6、12、24和48 h取血淋巴,应用流式细胞术测定血细胞的总数(THC)、活性氧(ROS)含量、一氧化氮(NO)含量以及凋亡率。结果显示,经0.5 mg/L硫化物胁迫48 h后,对虾THC显著下降至11.78×10~6个/mL,为对照组的72.7%(P0.05),ROS含量为对照组的225.2%(P0.05),血细胞凋亡率显著上升至7.42%(P0.05);经2.0 mg/L硫化物胁迫6 h开始,对虾THC呈现显著的下降(P0.05),血细胞ROS含量和凋亡率显著提高(P0.05);表明硫化物胁迫刺激对虾血细胞产生大量ROS,诱导血细胞凋亡,从而导致THC下降,这一过程可能是硫化物导致虾类细胞免疫下降的重要机制;随着硫化物浓度的升高,其细胞毒性作用明显提高。血细胞NO含量在2.0 mg/L硫化物胁迫12和48 h时显著升高(P0.05),推测NO可能在硫化物胁迫防御调控中起着信号因子的作用。  相似文献   

10.
以鲜活饵料双齿围沙蚕(Perinereis aibuhitensis)、赤子爱胜蚓(Eisenia foetida)和人工配合饵料投喂凡纳滨对虾(Litopenaeus vannamei),并测定各种饵料对其生长和免疫指标的影响。结果表明,沙蚕和蚯蚓单独投喂或与人工配合饵料配合投喂都可显著提高凡纳滨对虾的生长速率,但用沙蚕单独投喂的对虾成活率较低。蚯蚓与人工配合饵料配合投喂可显著提高对虾血清中抗菌活力、溶菌活力、酚氧化酶活力和血细胞数量;蚯蚓单独投喂可显著提高血清中抗菌活力、酚氧化酶活力和血细胞数量,对血清中溶菌活力作用不明显。沙蚕与人工配合饵料配合投喂可显著提高对虾血清中抗菌和溶菌活力.但对血清中酚氧化酶活力和血细胞数量变化作用不明显;单独投喂沙蚕对所测各项免疫指标影响均不显著。研究结果证实:利用蚯蚓和沙蚕可显著提高对虾的生长速率,但蚯蚓的饵料效果优于沙蚕。[中国水产科学,2006,13(4):561—565]  相似文献   

11.
优化对虾腌制工艺条件,为即食对虾生产提供理论依据。将腌制后对虾挥发性盐基氮、菌落总数和感官评定为指标,通过单因素及响应面分析法,研究不同腌制条件(浓度、时间、料液比)对虾肉的影响。结果表明:腌制时间、料液比、加盐量对感官评定结果的影响显著;通过响应面交互作用分析与优化,最佳工艺条件为:加盐量13%、腌制时间2h、料液比1︰2,此时,感官评价结果为91.35。  相似文献   

12.
ABSTRACT

To understand biochemical characteristics, storage stability, and freshness indicators of white shrimp (Litopenaeus vannamei), changes in extractable nitrogenous compounds, microbial count, and sensory rating of white shrimp during storage at 25 and 4°C were investigated. Free amino acids showed a slow increase during storage at 25°C, but no obvious change was found at 4°C. Adenosine triphosphate (ATP) and adenosine diphosphate (ADP) were found at initial stage and decreased rapidly after storage. Both inosine 5′-monophosphate (IMP) and adenosine monophosphate (AMP) increased and then decreased during storage. Inosine, hypoxanthine, and the K-value gradually increased with time. The levels of total volatile basic nitrogen (TVB-N), NH3, and trimethylamine (TMA) of white shrimp increased with storage time at 25 and 4°C. The TVB-N, NH3, TMA, inosine, hypoxanthine, and K-value could be considered as freshness indicators of white shrimp during storage. However, the total plate count did not corroborate the acceptability recommended limits for white shrimp during storage. The sensory evaluation, associated with TVB-N, TMA, and K-value, showed the quality was unacceptable after 6 h storage at 25°C and 7 days at 4°C.  相似文献   

13.
以贵州草海自然水域捕获的新鲜小龙虾(Procambarus clarkii)为材料,采用单因素实验研究了提取溶液、料液比、提取温度、提取时间、提取次数对虾青素提取效果的影响,用分光光度法测定了草海小龙虾不同部位虾青素的含量。结果表明,以乙酸乙酯为提取溶液,料液比为1∶2(g∶mL),在60℃下提取2 h,重复提取两次,再此提取条件下虾壳中虾青素含量最高。在虾壳、虾肉和内脏三个部位中,虾壳中虾青素含量最高,虾肉和内脏中也含有少量虾青素,但是含量远低于虾壳中的含量,说明了小龙虾虾青素主要富集在虾壳中。  相似文献   

14.
Presence of multiple viruses in non-diseased, cultivated shrimp at harvest   总被引:2,自引:0,他引:2  
Histological examinations were carried out with 400 cultivated black tiger shrimp (Penaeus monodon) from 12 commercial rearing ponds from three different areas in Thailand over a period of 3 years. The shrimp were collected at or near harvest time as two arbitrary size groups of 10–20 each from each pond. Aside from size difference, they showed no gross signs of disease and were normally active. Pathognomonic histopathological lesions were found only for hepatopancreatic parvovirus (HPV) or monodon baculovirus (MBV). Although these were relatively frequent, no unusual shrimp mortality had occurred in any of the ponds examined. Severity of these infections was negatively correlated with shrimp size. When grouped together, HPV-infected shrimp gave mean lengths of approximately 6.5 cm that were significantly different from uninfected shrimp at 9 cm length, early in the cultivation cycle while MBV-infected groups of approximately 9 cm length were not readily distinguishable until uninfected shrimp were 10 cm or more, later in cultivation. Thus, HPV infection was correlated with more severe stunting than MBV. In addition to histopathological examination, polymerase chain reaction (PCR) assays for HPV, white spot syndrome virus (WSSV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) were carried out on one large sample of 240 shrimp from 6 ponds where visible lesions were apparent for MBV only. Surprisingly, 94% of the specimens gave a positive test for at least one of the four viruses. HPV and IHHNV alone or in combination were detected at high prevalence (approximately 60%) despite the absence of visible histological lesions and were confirmed by southern blot hybridization. Although the prevalence of the four viral pathogens was very high, it would normally have gone unnoticed, since normal shrimp are rarely examined for viruses.  相似文献   

15.
Growth, immunological and physiological parameters of white shrimp Litopenaeus vannamei reared at different salinity levels (1, 10, 15, 25 and 35 g/L) at stocking density of 214 shrimp/m3 were examined at 1, 30 and 63 days. Results showed that the total haemocyte count (THC) of shrimp decreased with time at all salinity levels, indicating a potential reduction in the resistance of shrimp against pathogens, since a low value of THC indicates a perturbation of the immune system. Glucose and protein values observed in the haemolymph throughout the study indicate that shrimp adapted well to low salinities (1, 10 and 15 g/L). Although of those shrimp reared at 10 g/L only 83.3% survived, at this salinity, shrimp depicted a higher glucose concentration in haemolymph at the beginning and end of the study.  相似文献   

16.
不同养殖模式的凡纳滨对虾品质的比较   总被引:1,自引:0,他引:1  
仪器分析法(营养成份分析和质构分析)与感官评价法有机结合,以对虾口感为主要考核指标,建立对虾品质鉴定体系,并以此法对无公害海水养殖、传统海水养殖及传统淡水养殖对虾3种不同养殖模式下生产的对虾品质进行比较.结果表明:3种对虾的机体营养成分组成差异不大,只有无公害虾肌苷酸含量明显高于其余两组,达2.76 mg·g-1.氨基酸分析中表明:无公害海水养殖对虾的必需氨基酸、非必需氨基酸、鲜味氨基酸及氨基酸总量等指标优于其余样品;无公害虾的感官指标基本上与海水虾相似,3种虾的色泽和气味指标差异不明显(P>0.05),无公害虾的滋味及口感均比其它两组对照好;多汁性指标则以淡水虾最佳.在质构分析方面,3种虾硬度指标差异显著(P<0.05),无公害虾与海水虾在肌肉的弹性及咀嚼性无显著性差异(P>0.05),与淡水虾差异显著(P<0.05),其结果与感官评价基本一致.本文全面比较3种对虾品质上差异,揭示对虾口感差异内在因素,为对虾品质评价提供了方法和手段.  相似文献   

17.
熟制与贮藏对凡纳滨对虾挥发性成分的影响   总被引:1,自引:0,他引:1  
为研究熟制与贮藏对凡纳滨对虾挥发性成分的影响,采用电子鼻及固相微萃取—气相色谱—质谱联用技术分析虾肉的挥发性成分,并采用相对气味活度值和感官评定法评价虾肉风味的变化。结果显示,熟制与贮藏对虾肉中的挥发性成分影响显著。凡纳滨对虾生虾、熟虾、熟虾冷却、熟虾冷却过夜及二次熟制虾分别被检出50、68、63、49和41种挥发性成分。二次熟制后,虾肉中的挥发性成分有所减少,感官上虾的特征鲜香气也略微减弱;一次熟制对虾肉的风味影响不大。生虾肉中检测出的挥发性成分如壬醛和癸醛等对风味有显著性影响;熟虾肉中检测出壬醛、癸醛和十四醛等;二次熟制的虾肉中检测出对风味影响较大的挥发性成分主要是十八醛、二丁基羟基甲苯等。熟虾经过夜(4°C)放置后,其中检测出的挥发性成分种类和总量均减少,但总量差异不显著。研究表明,熟制可显著增加挥发性风味成分种类和总量,二次熟制与一次熟制相比,凡纳滨对虾的关键风味物质种类和含量显著降低;熟虾冷却后4°C贮藏12 h风味差异不显著。  相似文献   

18.
Integrated shrimp-mangrove farming systems in the Mekong delta of Vietnam   总被引:2,自引:0,他引:2  
In recent years, mangroves have been seriously threatened by shrimp culture development in the Mekong delta of Vietnam. As one way of protecting the mangroves, efforts have been made to develop shrimp-mangrove integrated farming systems through State Forestry Fisheries Enterprises (SFFEs), involving a participatory approach. The present study investigated the shrimp-mangrove farming systems in Ngoc Hien district at the southern tip of the Mekong delta through a detailed farm-level survey, including technical, environmental, social and economic factors. A total of 161 shrimp-mangrove farms on the east and west coasts of Ngoc Hien district were surveyed. The results showed that on the East coast of the delta, the pH of the bottom soil, the water alkalinity, gate width ratio (ratio of gate width to pond area), pond age and mangrove density, and flooding level of ‘flat’ (flat is where the mangroves are planted) in the dry and rainy seasons were significantly correlated with shrimp pond yields. On the west coast, the pH of the bottom soil, dissolved inorganic phosphorus, ditch area, and flooding level of ‘flat’ were found to be significantly correlated with shrimp pond yields. An economic analysis, based solely on the economic returns from shrimp culture showed that the farming systems with a mangrove coverage of 30-50% of the pond area gave the highest annual economic returns. The results demonstrate a better economic return to farmers who maintain mangroves in their farming systems.  相似文献   

19.
This research work evaluates the impact of 1.2% pomegranate peel extract (Pp) (Punica granatum), 0.1% grapefruit seed (Gfs) (Citrus paradisi) extract, and synthetic preservative 1.25% sodium bisulfite on shelf life extension of Litopenaeus vannamei stored at 4 and 15°C. The application of isothermal titration calorimetry (ITC) for comparison of the extracts and chemical preservative on shrimp quality retention based on the overall heat production by microbial and enzymatic degradation was addressed. The occurrence of probable bioactive responsible for antimicrobial and antioxidant activity components in the extracts was examined through gas chromatography-mass spectrometry (GCMS). At 4°C, Pp-treated shrimps resulted in 6.73 logCFU/g, 6.93 logCFU/g, 5.31 mgN/100 g, and 0.58 mgMDA/kg for aerobic plate count, psychrotrophic bacterial count, trimethylamine, and thiobarbituric-acid reactive substance, respectively, on the 15th day. At 15°C, Pp-coated shrimps retained quality until day 4. Isothermal calorimetric analysis resulted in a rapid and sharp peak for fresh samples, whereas there was broad and delayed peak for shrimp treated with Pp and sodium bisulfite. These observations prove that Pp counterpart the chemical preservative and outperform Gfs on shrimp quality retention. Results also indicate that isothermal calorimetry can be a useful technique for shelf life predictions and comparative evaluation of extract impact on shrimp quality retention.  相似文献   

20.
Pelletized diets containing different amounts of sun-dried shrimp meal and brewer's yeast were tested. A relationship was observed between the content of shrimp meal and brewer's yeast in the diets and increased growth of juvenile shrimp, Penaeus stylirostris. Data suggested that in feeds containing 5% squid meal, up to half the shrimp meal can be replaced by brewer's yeast. These feeds should thus contain at least 15% shrimp meal and less than 15% brewer's yeast. A quadratic correlation was found between the rate of growth of juvenile shrimp and the percentage of linoleic acid in the diets. The best nutritional response should be obtained in rations containing 14.5% linoleic acid. The same type of relation was observed for the ratio of the linolenic series (ω3)/linoleic acid (106) with the ratio of 1.18 giving the best nutritional response for the diets tested in this study.  相似文献   

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