饲料挤压加工工艺

膨化挤压是在一定压力、水分和高温下的一种熟化工艺过程。在膨化挤压工艺中主要的设备是挤压机 (膨化机 ) ,挤压机能起到粉碎、混合、剪切、熟化、成形、膨化及灭菌等多种作用 ,可促使蛋白质变性。因为这个过程改变物质结构 ,所以膨化加工是一种复杂的物理和化学变化过程。挤压加工工艺适合水产饲料、宠物饲料以及其它特种养殖饲料的加工。用于水产饲料加工的优点有 :挤压加工工艺合并了加热和加压的作用 ,能够控制颗粒饲料密度、提高饲料转化率、增强饲料在水中的稳定性、提高养殖产量和效率。在水产饲料、宠物饲料加工方面 ,挤压加工工艺…     

Toward the Genetic Improvement of Feed Conversion Efficiency in Fish

Feed conversion efficiency (FCE) is the effectiveness with which feed is converted to saleable fish product. Feed costs are a major input to aquaculture production systems, and genetic improvement in FCE may therefore have an important influence on profitability. FCE is usually expressed by a composite measure that combines feed intake and growth rate. The two most common measures are feed conversion ratio (feed intake/weight gain over a specified time interval) and its inverse, feed efficiency. Feed conversion ratio and feed efficiency are measures of gross FCE, because they do not distinguish between the separate energy requirements of growth and maintenance. There is abundant evidence of substantial genetic variation in FCE and its component traits in terrestrial livestock species and, although data are few, the same is likely for cultured fish species. The major problems with selecting from this variation to genetically improve FCE in fish species are:
It appears impractical to measure feed intake on individual fish, so that family mean data must be used.
We do not know the optimal time period over which to test fish for FCE.
We do not know the genetic correlations between FCE under apparent satiation or restricted intake conditions, or between FCE at different times in the production cycle.
If these problems can be overcome, selection to improve FCE might be best achieved by measuring feed intake of growing animals, and by utilizing genetic correlations that are likely to exist between feed intake and other production traits to develop a weighted selection index.     

ＭＨＣ基因的遗传变异及其与鱼类抗病性研究进展

概述了主要组织相容性复合体(MHC)的结构与功能以及在脊椎动物特别是鱼类中的研究进展。对MHC基因的遗传变异与鱼类抗病性机制做了较为详细的阐述,介绍了MHC的遗传变异与多种鱼类抗病性关系的研究进展,重点介绍了草鱼MHC基因的研究。展望了MHC基因在鱼类及草鱼未来抗病育种中的研究前景。     

MHC基因的遗传变异及其与鱼类抗病性研究进展

概述了主要组织相容性复合体（MHC）的结构与功能以及在脊椎动物特别是鱼类中的研究进展。对MHC基因的遗传变异与鱼类抗病性机制做了较为详细的阐述,介绍了MHC的遗传变异与多种鱼类抗病性关系的研究进展,重点介绍了草鱼MHC基因的研究。展望了MHC基因在鱼类及草鱼未来抗病育种中的研究前景。     

几种常见调质器的工作机理

随着饲料工业的不断发展，市场对颗粒饲料品质的要求也越来越高。调质作为饲料加工的组成部分，其作用也越来越被重视，特别是近几年来国内外水产养殖业的迅猛发展，加之水产饲料对颗粒品质的特殊要求，使饲料调质工艺与设备得到了突飞猛进的发展，调质设备的种类也层出不穷。     

热塑挤压蒸煮技术在鱼蛋白综合开发方面的应用

低值鱼蛋白的开发利用问题一直受到各国关注,对鱼蛋白的综合利用手段也作过多种尝试,相继有多种形式或用途不同的鱼蛋白制品问世。迄今为止,饲料蛋白制品仍为主要利用形式,同时,由于食用鱼蛋白具有蛋白质利用率高的优点,其技术和产品的研发越来越重要。现代鱼品加工技术中,食用     

环保型水产饲料的研究进展

长期以来,水产养殖业中存在着饲料利用率低,环境资源有限和食品安全等问题,随着养殖规模的不断扩大,这些问题越来越严重.饲料的配制和使用不科学是导致上述问题的一个主要原因,水产饲料向环保型发展势在必行.文章从减少氮、磷排放,使用无公害绿色添加剂和改进饲料加工工艺等方面阐述了环保型水产饲料的研究现状和发展趋势.     

挤压蒸煮技术在水产饲料业的应用

我国饲料工业是一个新兴的产业,起步于20世纪70年代中后期,首先是畜禽饲料业的发展,直到80年代初水产饲料工业才开始启动。我国饲料工业生产的配合饲料产量呈直线上升,产值位居我国国民经济41个主要行业中的第20位,成为国民经济的基础产业之一[1~3]。20世纪80年代以来,我国的水产饲料工业发展很快,对我国水产养殖业的高产、稳产起了重要作用。但随着养殖规模的不断扩大以及养殖品种的多样化发展趋势,对水产饲料的要求也越来越高,传统加工方法生产的配合饲料已难以适应现代水产养殖业发展的需要,而应用挤压蒸煮技术生产的颗粒膨化饲料能较好…     

喹乙醇在鱼饲料和鲤鱼组织中的残留量

测定了喹乙醇在鱼饲料和鲤鱼组织中的残留量。用体积分数为 2 0σ/v的甲醇提取饲料中的喹乙醇。用乙腈 -乙酸乙酯 (体积比为 3∶2 )提取鱼组织中的喹乙醇。高效液相色谱条件 :Hypersil-C18为分离柱 ( 12 5mm× 4 0mm) ;流动相为 15σ/v甲醇 ;体积流量 1 0ml·min-1;紫外检测波长 2 60nm。喹乙醇在 2～ 2 0 μg·ml 1线性关系良好 ,相关系数 0 9996。测定下限为 2 0mg·kg 1。     

Molecular Screening and Biocontrol of Aflatoxigenic Fungi in Fish Feed

ABSTRACT

Contamination of fish feed (FF) with aflatoxigenic fungi is an ongoing hazardous risk and is the first route for transferring aflatoxins to consumers from fish products. Prevention is the gold standard to deal with microbial food contamination. Different FF samples (n = 38) were screened for the occurrence of fungal contamination, and identified Aspergillus flavus isolates were assessed for the presence of aflatoxigenic production genes (Nor-1, Ver-1, and Omt-A) and the ability to produce aflatoxins. Biocontrol of aflatoxigenic A. flavus was proposed via exposure to plant (Cinnamon bark, Athl, and Lilac leaves) smoldering fumes (PSF). Numerous fungal species were identified from FF; Aspergillus spp. was the prevalent genus, followed by Penicillium spp. and Fusarium spp. The complete set of aflatoxigenic genes was detected in 54.8% of A. flavus isolates and was correlated with their aflatoxin-producing ability. The PSF exposure was successful for inhibiting A. flavus growth in agar media and in contaminated fish feed. Cinnamon PSF was the most effective and could entirely inhibit fungal growth at a proportion of 20 g/m³ in both treatments. The PSF exposures could be suggested as effectual techniques for complete biocontrol of aflatoxigenic fungi in fish feed to protect fish and consumers from their threatening effects.     

人工雌核发育在鱼类遗传育种中的应用

阐述了鱼类人工雌核发育的基本原理,介绍了人工雌核发育在研究鱼类性别决定机制,养殖生产中的性别控制和鱼类性别遗传机制分析及选育新品种等方面的应用成果。     

鱼类遗传连锁图谱的研究进展

我国是渔业大国,十分重视鱼类品种的培育.现己培育出的新品种基本上均是通过形态特征来进行选育,由于形态及表型是遗传因素与环境因素相互作用的综合结果,仅根据表型得到的优良性状在选育中不稳定,且育种周期相当长.     

对虾饵料用酵母菌的选育研究

将Ｙ２、Ｙ３、Ｙ４、Ｙ５、Ｙ６、Ｙ７株饵料酵母菌，接种到培养基上培养，测定Ｂ族维生素、维生素Ｄ以及蛋氨酸，赖氨酸的含量，并进行紫外线和ＥＭＳ复合诱变处理，结果发现：Ｙ３、Ｙ４、Ｙ７是３株优良酵母菌，其始发株和诱变株不仅富含Ｂ族维生素和维生素Ｄ，而且蛋氨酸和赖氨酸含量丰富，是理想的对虾饵料用酵母菌。     

蚕粉替代鱼粉对加州鲈幼鱼生长、饲料利用及体成分的影响

本研究评价了蚕粉对加州鲈(Micropterus salmonides)幼鱼生长、饲料利用率和体成分的影响。选用初始均体重为(3.13±0.04) g的加州鲈540尾,随机分成6个实验组,每组3个重复,每个重复30尾实验鱼,分别以蚕粉替代0(对照组)、10%、20%、30%、40%和50%的鱼粉设计出6种等氮、等能的饲料配方,按照配方配制实验饲料。由于后期养殖气温下降,不适合继续进行实验,本养殖时间为45 d。结果显示,加州鲈的增重率(WGR)、特定生长率(SGR)及蛋白质效率(PER)均随蚕粉替代水平的升高呈先上升后下降的变化趋势,且其WGR、SGR和PER均在蚕粉替代水平为30%时达到最大(分别为227.87%、1.98%/d和164.55%)(P0.05);饲料系数(FCR)则随蚕粉替代水平的升高呈先降后升的变化趋势,且在蚕粉替代水平为30%时达到最低(为1.43)(P0.05);肥满度(CF)、肝体比(HSI)、脏体比(VSI)则随蚕粉替代水平的升高而呈先上升后下降并趋于稳定的趋势(P0.05);实验期间各组实验鱼的成活率(SR)差异不显著(P0.05)。通过二次回归分析可知,加州鲈幼鱼WGR、SGR、FCR及PER最优时饲料的蚕粉替代比例分别为19.90%、22.00%、18.11%和17.90%;加州鲈全鱼粗脂肪含量随蚕粉替代水平的升高呈先降低后升高的变化趋势(P0.05),粗蛋白含量随蚕粉替代水平的升高无明显变化(P0.05),水分除蚕粉替代水平为10%和40%组差异显著外(P0.05),其余各实验组差异不显著(P0.05),蚕粉替代水平大于20%时,全鱼灰分显著降低(P0.05)。在本实验条件下,综合考虑实验鱼的生长指标、饲料利用和体成分,饲料中蚕粉适宜的替代水平为17.90%～22.00%。     

稚鱼生物饵料的DHA营养强化

综述了国内外海水稚鱼生物饵的ＤＨＡ营养强化技术研究及其应用状况，轮虫、卤虫的营养强化方法和注意事项。     

流溪河保护区鱼类群落结构及其时空变动

为了解流溪河光倒刺鲃国家级水产种质资源保护区鱼类群落结构,分析不同河段、不同季节鱼类群落多样性的变化,于2017年12月-2018年10月对保护区上、中、下游的鱼类开展了每个季度一次的调查。调查结果显示,共采集鱼类57种,隶属于5目14科50属,其中鲤形目43种、鲈形目6种、鲇形目5种,合鳃鱼目2种,鳉形目1种;计算57种鱼类的相对重要性指数,结果显示,尼罗罗非鱼、越南■及鲤鱼为2017-2018年度优势种;Shannon-Wiener多样性指数、Margalef丰富度指数和Pielou均匀度指数计算结果显示,下游鱼类群落的多样性及均匀度最高,夏季鱼类群落的多样性、丰富度及均匀度最高;各监测点之间的种类相似性系数显示,保护区上中游、上下游之间鱼类种类组成为中等不相似,中下游种类组成为中等相似,春夏、春冬、夏冬及夏秋季节鱼类种类组成为中等不相似,春秋、秋冬季节为中等相似;ABC分析结果显示,春、夏及冬季鱼类群落处于稳定状态,秋季处于中度干扰状态。     

Toxicity of Peracetic Acid to Fish: Variation among Species and Impact of Water Chemistry

There has been strong interest in the use of peracetic acid (PAA) in aquaculture as it can be used to disinfect water and hard surfaces and thereby eliminate or lower the burden of fish pathogens. Unfortunately, there has been little research on the toxicity of PAA to fish. Twelve species of fingerling fish that are important to aquaculture were exposed to PAA for 24 h in static toxicity bioassays in well water. These fish were: fathead minnow, Pimephales promelas; black‐nose crappie, Pomoxis nigromaculatus; bluegill, Lepomis macrochirus; blue tilapia, Oreochromis aureus; channel catfish, Ictalurus punctatus; golden shiner, Notemigonus crysoleucas; goldfish, Carassius auratus; grass carp, Ctenopharyngodon idella; largemouth bass, Micropterus salmoides; rainbow trout, Oncorhynchus mykiss; sunshine bass, Morone chrysops × M. saxatilis; and walleye, Sander vitreus. Median lethal concentration (LC₅₀) values were estimated with the trimmed Spearman–Karber method using nominal PAA concentrations. The mean 24‐h LC₅₀ values ranged from 2.8 to 9.3 mg/L PAA. Fathead minnow were very sensitive and blue tilapia were very tolerant to PAA exposure; LC₅₀ values of other species tested were within the range of 4.1–6.2 mg/L PAA. More importantly, the 24‐h no‐observed‐effect concentration (NOEC) ranged from 1.9 to 5.8 mg/L PAA; the NOEC would be considered as the safe range for culturists to investigate the use of PAA. Decreased alkalinity/hardness increased the toxicity of PAA, while a small increase of dissolved organic content had no effect on PAA toxicity. Results of the present study are important information on the safe application of PAA for the aquaculture industry.     

MHC基因在鱼类遗传育种中的研究与应用

主要组织相容性复合体（MHC,Major histoeompatibility complex）是最具多态性的免疫分子。其多态性主要取决于群体内MHC基因的大量等位基因及等位基因间高度的序列变异。等位基因的序列变异主要发生在抗原肽结合区（peptide binding region,PBR）,这决定了不同基因型个体的免疫力差异。鱼类受多倍化影响,MHC基因的多态性还表现在同一基因存在多个基因座位（多拷贝）。MHC的高度多态性及与机体免疫力的相关性,使其在鱼类遗传进化、抗病育种等方面倍受关注。本文介绍了有关鱼类MHC基因的结构、功能及其在遗传育种中的应用。