菜籽粕营养价值及菜籽浓缩蛋白在水产饲料中的应用

全球鱼粉资源的短缺迫使水产养殖业相关从业者寻找可替代水产饲料中鱼粉的优质蛋白源,菜籽粕是一种来源广泛、蛋白含量高、氨基酸组成相对平衡、富含矿物元素和维生素的具有较高利用价值的植物蛋白源。本文总结了近年来关于菜籽粕在水产饲料中应用的研究进展,综述了菜籽粕的营养价值和限制因素,同时介绍了菜籽粕的加工产物—菜籽浓缩蛋白的营养价值及其在水产养殖中的应用,论述了菜籽浓缩蛋白在水产饲料中应用的可行性。     

豆渣作为蛋白源在水产饲料中的研究进展

豆渣作为大豆制品的主要副产物,含有丰富的蛋白质且必需氨基酸含量丰富,具有较高的营养价值.我国是世界第一水产养殖大国,但鱼粉等饲料蛋白源的匮乏及市场价格的节节攀升严重制约了我国水产饲料工业的发展.因此,开发新型饲料蛋白源将成为我国水产饲料工业发展的助推器.本文综述了豆渣的营养成分、豆渣中的抗营养因子以及在水产动物饲料中的研究,为豆渣在水产饲料生产中的运用提供指导.     

水产饲料廉价蛋白源的开发利用研究概述

随着集约化水产养殖业的发展,配合饲料的需求量越来越大,饲料蛋白源供应不足的问题显得尤为突出。鱼粉是目前最常见的水产饲料蛋白源,然而随着渔业资源衰退,鱼粉价格不断上涨,开发利用新的水产饲料蛋白源显得迫在眉捷。本文详述了常见替代饲料蛋白源的种类、特性、利用现状,同时阐述各种替代蛋白源在水产养殖生产中的利弊,以期为今后的研究和利用提供参考。一、植物性蛋白源的开发利用我国是一个农业大国,植物资源极其丰富,可作为植物性蛋白源的主要有豆科籽实、油饼、菜饼、棉籽饼等,食品和医药工业     

卤虫蛋白源在水产养殖中的应用及开发新途径

鱼粉具有必需氨基酸和脂肪酸含量高,糖类含量低,适口性好,抗营养因子少及能够被水产养殖动物很好的消化吸收等优点,一直以来是水产饲料中不可或缺的优质蛋白源.但是随着我国水产养殖业的快速发展及产量的增加,水产养殖动物对优质蛋白源的需求正在急剧增加.因此找到和开发能够部分或完全替代鱼粉的动物性蛋白源成为水产养殖工作者当前非常紧迫的任务.     

水产饲料中鱼粉替代物的研究进展

鱼粉是水产饲料中不可缺少的优质蛋白源。随着集约化养殖的迅猛发展,鱼粉的需求量急剧上升。然而,由于过度捕捞及厄尔尼诺现象等的影响。世界鱼粉的总产量正逐年下降,价格却不断上涨,这些因素严重制约了水产养殖业的进一步发展。大量的研究表明,用大豆酶解蛋白、发酵植物蛋白、虾蛄蛋白浆、酶解血球蛋白粉、大豆浓缩蛋白等部分或完全替代鱼粉是可行的。本文就近年来鱼粉替代物在水产养殖业的最新研究作一概述。     

大豆浓缩蛋白作为水产饲料蛋白源的评价

通过分析大豆浓缩蛋白各种营养成分及抗营养素组成和含量,并与进口鱼粉进行比较,对大豆浓缩蛋白作为水产饲料蛋白源的利弊进行全面的评价。结果表明：大豆浓缩蛋白粗蛋白质含量较高,一般都可以超过进口鱼粉;氨基酸较平衡,怛组氨酸、蛋氨酸和赖氨酸较进口鱼粉低;抗营养因子和磷含量较低,也是大豆浓缩蛋白相对鱼粉的一个重要优点。可作为水产动物饲料蛋白源部分替代饲料中的鱼粉。     

日粮中酶解蛋白肽替代鱼粉对异育银鲫产生的影响

水产饲料蛋白源主要是鱼粉和豆粕等，国产鱼粉年产量仅20万吨，世界鱼粉年产量约为600万吨，而且有逐年下降之势。在目前我国水产配合饲料使用率仅10％的情况下已感到鱼粉来源紧张；豆粕产量自1990年以来虽有逐年增长之势，但随着畜禽的规模化养殖和饲料工业的发展，对蛋白源的需求量也逐年增加，水产饲料业蛋白源的供应压力日趋严重。因此，如何解决经济实用的水产饲料蛋白源的问题是一个既紧迫又艰巨的任务。     

水解鱼蛋白的营养特征及其在水产动物营养饲料中的研究进展

鱼粉短缺是当今水产饲料行业中亟待解决的难题,而水产品加工副产品占水产品的总重量超过60%,因此,充分利用水产品加工副产品,提高其营养价值,是解决鱼粉短缺的重要途径。水解鱼蛋白是水解水产品加工副产品而得到的富含游离氨基酸和不同肽链长度的蛋白寡肽,目前,越来越多的研究证明,其对水产养殖动物的生长性能具有重要的促进作用。本文从水解鱼蛋白的制备、营养特性及水产饲料中的研究和应用方面展开综述,系统论述近年来水解鱼蛋白在水产动物营养相关领域的研究成果,并提出在水产饲料中的进一步研究方向,以期为水解鱼蛋白在水产动物营养学研究及其在水产饲料中的应用提供参考。     

几种昆虫的人工培育及其在水产饲料中的应用进展

简述了黑水虻幼虫、蝇蛆、黄粉虫以及其他昆虫的人工培育及其在水产饲料中的应用。指出了目前昆虫蛋白应用于水产饲料存在的问题。提出，昆虫蛋白应用于水产饲料中极具开发前景，一方面营养丰富，高蛋白且可持续，是鱼粉的优质替代品，另一方面含有抗菌肽和甲壳素等天然活性物质，对水产动物的生长免疫力和抗病力有较好的正面作用。     

美国以昆虫作鱼饲料的试验已进入生产应用

由于养殖饲料的需求量不断增加,作为饲料中蛋白源的鱼粉和作为制造鱼粉的小杂鱼越来越少,为了减少对小杂鱼的捕捞,国际和各区域渔业组织曾作出过许多限制措施,以确保海洋渔业的可持续发展,在这样的大背景下,美国密西水产研究所开展的以昆虫作水产饲料蛋白源的课题已可以进入生产应用。该项目是以玉米和棉花的两种虫蛾作为昆虫源,     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

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.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

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.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

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).     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.     

Influence of the antibacterial herbs, Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia on the survival, growth and bacterial load of Penaeus monodon post larvae

The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 10³ to 3.76 × 10⁵ cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 10⁵ cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.