Computer vision systems (CVS) for moisture content estimation in dehydrated shrimp     

Mohebbat Mohebbi  Mohammad-R Akbarzadeh-T  Fakhri Shahidi  Mahmoud Moussavi  Hamid-B Ghoddusi 《Computers and Electronics in Agriculture》2009,69(2):128-134

This paper presents a method based on computer vision systems (CVS) to estimate shrimp dehydration level by analyzing color during drying process. Since the most commonly used color space in food industry is L*a*b, transformation of RGB digital images to L*a*b units was carried out using direct two steps model with γ factor. Experimental data obtained from images captured at different drying temperatures (100–130 °C) and several time intervals (15–180 min) were analyzed with a complete randomized block design (CRBD), and the means were compared with Duncan's multi-range test. Multiple linear regression (MLR) and artificial neural networks (ANN) were applied for correlating the color features to moisture content of dried shrimp determined chemically. Results obtained with these two models lead to 0.80 and 0.86 correlation coefficients in MLR and ANN models, respectively. While there is no statistical difference at p < 0.05 between the two modeling approaches, both approaches indicate successful prediction of shrimp dehydration with high correlation to those found by the more expensive and intrusive chemical method. The automated vision based system, therefore, has the advantage over conventional subjective methods and instrumental ones for being objective, fast, non-invasive, inexpensive and precise.  相似文献   

Experimental horizontal transmission of Enterocytozoon hepatopenaei in post‐larvae of whiteleg shrimp,Litopenaeus vannamei     

Kesavan Karthikeyan  Raja Sudhakaran 《Journal of fish diseases》2019,42(3):397-404

Enterocytozoon hepatopenaei (EHP) is a microsporidian parasite that causes hepatopancreatic microsporidiosis (HPM) in penaeid shrimp. HPM was observed in several countries, including Thailand and India; it has become a prominent pathogen in shrimp culture. Based on observations on EHP infection in the wild, the route of transmission has been hypothesized. Identification of artificial EHP infection procedures can facilitate our understanding of EHP transmission. Experimental transmission of EHP was attempted using the immersion and oral infections of infection. In the immersion mode, post‐larvae (PL) were exposed to an EHP tissue homogenate (0.2%) by immersion for 48 hr. Experimental samples were collected at various time points, and infection was confirmed using polymerase chain reaction, haematoxylin and eosin staining, transmission electron microscopy and modified trichrome staining. All test results revealed successful EHP transmission. Similar results were obtained through oral infection (oral infection). Innate immune gene expression patterns during infection were analysed; prophenoloxidase, crustin and superoxide dismutase were upregulated at 6, 6 and 48 hr post‐challenge, respectively. Experimental infection procedures facilitate the development of diagnostic and prevention strategies. This is the first study demonstrating the experimental transmission of EHP in shrimp PL.  相似文献   

中国水产动物病毒学研究概述   总被引：5，自引：4，他引：1  

桂朗  张奇亚 《水产学报》2019,43(1):168-187

本研究简要概述了过去几十年来中国水产养殖动物病毒学的代表性研究成果,主要涉及鱼类病毒、虾类病毒、两栖和爬行动物病毒等。此外,本研究还展望了水产动物病毒学研究的发展趋势,以有助于加深对中国水产养殖动物病毒学研究现状和未来发展的认识。  相似文献   

对虾微量元素研究进展     

焦乐飞  代恬梦  金敏  孙蓬  周歧存 《水产学报》2019,43(10):2093-2101

微量元素作为多种酶的辅助因子或结构成分,参与机体多种新陈代谢过程,在维持动物健康和正常生理功能中发挥着极其重要的作用。动物对微量元素营养需求极少,但缺乏、过量或摄入不平衡都会对动物机体生长代谢、免疫、繁殖等带来严重不良影响。本文较详细、系统地总结了国内外关于微量元素在对虾生长代谢、免疫、疾病预防、性腺发育等方面的作用,以及对虾对无机和有机微量元素的吸收、转运和代谢机理,为今后开展对虾优质配合饲料研发提供理论依据。  相似文献   

亚硝酸盐氮对日本囊对虾幼虾的急性毒性研究     

陈亭君  刘建勇  申玉春  栗志民 《渔业现代化》2019,(3):35-40

在水温(28±0.2)℃、盐度29.8±0.2、pH8.0±0.2和溶氧6.0mg/L的条件下,将体长(49.28±4.79)mm日本囊对虾(Marsupenaeus japonicus)幼虾放在盛水20L的100L白桶中,用NaNO2(分析纯)溶于新鲜海水配制成2000mg/L的母液,使试验组水中亚硝酸盐氮(NO2^--N)质量浓度为151.36、239.88、380.19、602.56、954.99mg/L,采用静水毒性试验法研究了亚硝酸盐氮对日本囊对虾幼虾的急性毒性。结果显示,NO2^--N毒性效应与质量浓度和胁迫时间呈正相关。在同一时间下日本囊对虾的死亡率随着NO2^--N质量浓度的升高而增加;在同一质量浓度下对虾的死亡率随着时间的延长而升高。NO2^--N对日本囊对虾24、48、72、96h的半致死质量浓度(LC50)分别为1806.100、970.939、780.050、427.391mg/L,安全质量浓度为42.739mg/L。NO2^--N质量浓度为151.36、239.88、380.19、602.56、954.99mg/L的半致死时间(LT50)分别是120.008、111.954、94.207、78.810、60.102h。试验表明,日本囊对虾养殖水体中NO-2-N质量浓度应控制42.739mg/L以下。  相似文献   

Genetic parameters of survival in four generations of Indian white shrimp (Fenneropeneaus indicus)     

Mohamed E. Megahed  Gamal Elmesiry  Khaled Mohamed  Arun K. Dhar 《Journal Of Applied Aquaculture》2019,31(2):121-139

This study evaluated the genetic variance for survival at harvest of Indian white shrimp (Fenneropenaeus indicus) using a pedigreed synthetic population generated upon collecting broodstock from different fishery grounds in Egypt. The estimated heritabilities (h² ± SE) of survival from generations G₀ to G₃ ranged from 0.144 ± 0.026 to 0.008 ± 0.030 using a model that included the common environmental effect (c²). Low heritability (0.014 ± 0.015) was estimated across generations with the inclusion of common environmental effect (c²). However, the h² of survival from G₀ to G₁ ranged from 0.569 ± 0.071 to 0.410 ± 0.011 when c² was not included. The genetic correlation for survival between different ponds from G₀ to G₃ was moderate to high (0.79 ± 0.042 to 0.83 ± 0.012) but significantly different (P < 0.05). There were low correlation coefficients (?0.237 ± 0.089 to 0.316 ± 0.073) between body weight estimated breeding value (EBV) and survival EBV of families in four generations.  相似文献   

A new map of the tiger shark (Galeocerdo cuvier) genetic population structure in the western Atlantic Ocean: Hypothesis of an equatorial convergence centre     

Camila B. Carmo  Bruno L.S. Ferrette  Smia M. Camargo  Fbio F. Roxo  Rui Coelho  Ricardo C. Garla  Claudio Oliveira  Andrew N. Piercy  Hugo Bornatowski  Fausto Foresti  George H. Burgess  Fernando F. Mendona 《水产资源保护:海洋与淡水生态系统》2019,29(5):760-772

Effect of feeding frequency on growth and digestive enzyme activity in Litopenaeus vannameiduring the grow‐out phase in biofloc system     

Roberta Cavalcanti Nery  Camila Barros Costa  Flvio Rodrigues  Roberta Soares  Ranilson de Souza Bezerra  Silvio Peixoto 《Aquaculture Nutrition》2019,25(3):577-584

The present study evaluated the effects of feeding frequency during the grow‐out phase of Litopenaeus vannameiin biofloc system. The experiment comprised of four treatments with three replicates each, corresponding to the following feeding frequencies: one (8:00 a.m.), two (8:00 a.m. and 4:00 p.m.), three (8:00 a.m., 12:00 p.m. and 4:00 p.m.) and four times a day (8:00 a.m., 10:00 a.m., 12:00 p.m. and 4:00 p.m.). Zootechnical performance and digestive enzyme activity were monitored for 63 days. At the end of the experiment, the highest survival rates were found for the individuals fed three and four times a day. Wet weight gain (6.63 g) and specific growth rate (3.46% per day) of the individuals fed three times a day were significantly higher compared to animals fed one and four times a day, but did not differ significantly to the group fed twice a day (6.15 g and 3.46% per day, respectively). The digestive enzyme activities were not affected by the feeding frequency, but negative correlations were found between these activities and shrimp weight. It is recommended that L. vannamei should be fed three times a day during the grow‐out phase in a biofloc system under the conditions used in this study.  相似文献   

Dietary 5‐aminolevulinic acid enhances adenosine triphosphate production,ecdysis and immune response in Pacific white shrimp,Litopenaeus vannamei (Boone)     

Ivane R. Pedrosa‐Gerasmio  Hidehiro Kondo  Ikuo Hirono 《Aquaculture Research》2019,50(4):1131-1141

Previous studies have shown that 5‐aminolevulinic acid (5‐ALA), a precursor of haem, can enhance haem synthesis and the activity of haemoproteins. Here, we investigated the effects of dietary 5‐ALA on Pacific white shrimp, Litopenaeus vannamei (Boone). Dietary groups included basal diet (BD, control) and BD plus 15, 30 and 60 ppm 5‐ALA (ALA15, ALA30 and ALA60 respectively). Hepatopancreas adenosine triphosphate (ATP) levels increased with increasing 5‐ALA concentration (ALA60 p < 0.05) after 2 weeks of feeding. 5‐aminolevulinic acid diets significantly increased the expression of ecdysis‐related genes: nuclear receptor E75 and chitinase 4 (ALA15, ALA30, ALA60), cytochrome P450 Shade (ALA60), chitinase 1 (ALA60) and chitinase 3 (ALA15, ALA60). Catalase (CAT) and prophenoloxidase gene expression levels were also significantly higher in ALA60 after 12 weeks of feeding. Six hours after L. vannamei were exposed to Vibrio parahaemolyticus, total haemocyte count (ALA60) and gene expression levels of CAT (ALA30, ALA60) were significantly higher in 5‐ALA groups compared to the control. 5‐aminolevulinic acid diets also increased survival of L. vannamei following V. parahaemolyticus immersion challenge. These results suggest that supplementing L. vannamei diets with 5‐ALA can enhance ATP production, immune response against V. parahaemolyticus, total haemocyte count and expression of some immune‐related genes. 5‐aminolevulinic acid can also induce ecdysis‐related gene expressions, without adversely affecting growth.  相似文献   

Evaluation of antimicrobial products used in tilapia (Oreochromis spp.) and whiteleg shrimp (Litopenaeus vannamei) aquaculture     

Kang Li  Liping Liu  Jia Zhan  Marie‐Louise Scippo  Anders Dalsgaard 《Aquaculture Research》2019,50(3):925-933

Despite the importance of aquaculture increases for feeding the growing world population, professional farm management and proper use of aquaculture products or drugs are needed. It is important to know the quality of commercial antimicrobial products on the market while there is wide use of antimicrobials to treat fish diseases. The most commonly used antimicrobial products were identified from a previous survey, included amoxicillin, enrofloxacin, florfenicol, sulphadiazine, sulphamonomethoxine and sulphadimidine. Eight local chemical supply shops were randomly sampled in representative aquaculture areas in Maoming and Zhanjiang districts of south China in 2013. In this study, only eight products contained active substances within ±10% of the concentration declared on the product label among the 30 different most used commercial products; while six products did not contain any of the declared antimicrobials. Three products without labels were sold as ‘pure antimicrobial’ and had high concentrations of active antimicrobials. Furthermore, most products only provided ambiguous information on the packages on both antimicrobial usage and dosage; and only one product stated how to prepare medicated feed which is important for efficient usage. The results of this study showed that the aquaculture antimicrobial products sold on the market were of low quality and thus compromised effective fish disease treatment. Moreover, insufficient information on products’ labels would provide limited instruction on correct antimicrobial usage. Inspection and supervision by both private companies and the government's sector require strengthening.  相似文献