中国对虾对16种饲料的蛋白质和氨基酸的消化率

本文利用三氧化二铬为指示物，测定了平均体长在８．０－９．０厘米的对虾对卤虫等１６种不同饲料源的蛋白质和氨基酸的消化率。按消化率的高低顺序排列则为：卤虫，蓝蛤，熟豆饼、秘鲁鱼粉、生豆饼、ＦＳ酵母、花生饼、ＥＳＢ酵母、棉籽饼、肉粉、菜籽饼、羽毛粉、ＴＰＬ－３２酵母，血粉、麦麸和玉米粉，该研究结果为评价某一饲料源的营养价值和开发适于中国对虾的人工配合饲料提供了依据。     

草鱼对17种饲料原料粗蛋白和粗脂肪的表观消化率

试验以Cr2O3为指示物，测定草鱼对进口鱼粉、国产鱼粉、蟹粉、肉粉、肠衣粉、酵母、菜饼、黄菜饼、黑菜饼、双低菜仔粕、豆粕、膨化大豆、芝麻饼、棉粕、玉米胚芽饼、玉米蛋白粉和酒糟粉17种试验原料中粗蛋白和粗脂肪的表观消化率。试验饲料由基础饲料和试验原料以70：30的比例（质量比）混合挤压成硬颗粒饲料。结果表明，草鱼对鱼粉、菜籽饼籽、豆粕和膨化大豆等质量好的蛋白饲料的表观消化率较高、其干物质、脂肪和蛋白质的表观消化率均在80％以上；草鱼对酵母、菜籽饼粕、豆粕和膨化大豆等饲料的干物质、脂肪和蛋白质的表观消化率均与鱼粉一致。     

南方大口鲶人工配合饲料网箱养殖技术操作规程(二)

５饲料及其投喂５．１根据大口鲶不同生长阶段的营养需要，制作４个饲料配方，即转食饲料、鱼种饲料、成鱼饲料和秋后饲料。它们的主要营养指标见表２。５．２动物性蛋白源以红鱼粉、白鱼粉、蚕蛹、肉骨粉、啤酒酵母、菌体蛋白饲料为主；植物性蛋白源有豆饼、菜饼、花生饼...     

花鱼骨 鱼种对11种蛋白质饲料原料的消化率

为获得花(鱼骨)对常用蛋白源的可消化性数据,按照"70%基础饲料+30%被测原料"的饲料配制方法,用三氧化二铬指标物,测定了花(鱼骨)鱼种对白鱼粉、褐鱼粉、四海豆粕、加佳豆粕、血粉、蚕蛹粉、啤酒酵母、菜籽粕、棉籽粕、花生粕、玉米蛋白粉等11种蛋白原料干物质和粗蛋白的表观消化率.结果表明:花(鱼骨)对11种原料的干物质和蛋白质表观消化率分别为54.84%～86.96%和69.17%～96.77%.其中自鱼粉、褐鱼粉、血粉以及豆粕、啤酒酵母等的干物质消化率较高,白鱼粉、褐鱼粉及豆粕、花生粕等的蛋白质消化率较高.     

翘嘴红鲌鱼种对八种蛋白质饲料原料的消化率

本试验按照“70 %基础饲料 +30 %被测原料”的饲料配制方法 ,用三氧化二铬指标物 ,测定了翘嘴红鱼种 (体重 12 5± 1 5 g )对鱼粉、血粉、蚕蛹粉、酵母、豆粕、花生粕、菜籽粕、棉籽粕等 8种常用的饲料原料的干物质、蛋白质、粗脂肪的表观消化率。结果表明 :翘嘴红对 8种原料的干物质表观消化率和蛋白质表观消化率分别为 4 3 4 3%～ 86 90 %和 6 6 34%～ 95 18% ,对 5种原料的脂肪表观消化率为 6 6 6 9%～ 94 16 %。     

介绍几种鱼饲料新配方

北京水产所养殖罗非鱼配合饲料配方。豆饼35％、鱼粉15％、大麦粉8．5％、麸皮30％、玉米粉5％、槐叶粉5％。饲料系数为2．03。     

河蟹养殖技术之三:稻田培育蟹种技术

2003年,我们在稻田中进行了蟹种培育试验,并获得了良好的效果,实现投入产出比为1∶2.48。现将主要技术与方法总结如下:1.稻田 蟹种培育的稻田面积为0.28ha,水源充足且无污染,排灌方便,适合蟹种培育的要求。2.蟹苗 蟹苗选购于山东沿海地区的育苗场,为纯正中华绒螯蟹蟹苗,规格为15万只/kg,大小整齐,体质健壮,爬行迅速。3.饲料 投喂饲料的种类有水蚤、小鱼、小虾、鸡蛋、蚯蚓、鱼粉等动物性饲料,浮萍、瓜类、饼类、豆渣、麸皮、米糠等植物性饲料,以及蟹种专用配合颗粒饲料。配合颗粒饲料的配方为鱼粉25%,豆饼粉25%,菜饼粉23%,麦粉20%,…     

团头鲂对8种非常规饲料原料中营养物质的表观消化率

以0.5%的三氧化二铬(Cr2O3)为指示剂,由70%基础日粮和30%试验原料组成试验日粮研究了团头鲂对膨化羽毛粉、酶解羽毛粉、血粉、蚕蛹粉、玉米蛋白粉、玉米、碎米和大麦8种饲料原料的干物质、粗蛋白、粗脂肪、氨基酸、总磷及总能的表观消化率。试验鱼［平均体质量(250.83±2.12) g ］养殖于室内水族箱中(3.0 m×0.8 m×0.8 m),分别投喂相应的试验饲料1周后采用自排法收粪。结果表明:8种饲料原料的干物质、粗蛋白、粗脂肪、总氨基酸、总磷及总能的表观消化率的范围分别是68.07%～92.69%、81.54%～92.75%、84.82%～103.44%、63.07%～95.56%、41.48%～97.55%、68.91%～97.81%。其中各项营养物质的表观消化率均以玉米蛋白粉最高;4种动物蛋白原料中以蚕蛹粉中营养物质表观消化率最高,血粉次之;除粗脂肪外,酶解羽毛粉的消化率均高于膨化羽毛粉;3种能量饲料中,以大麦的蛋白及氨基酸表观消化率最高,但干物质、粗脂肪及能量的表观消化率均显著低于玉米和碎米。由此可见,玉米蛋白粉和蚕蛹粉分别可作为团头鲂优质的植物蛋白源和动物蛋白源,血粉、羽毛粉可搭配其他饲料少量使用。玉米和碎米能值较高,可作为团头鲂的主要能量饲料,大麦由于氨基酸组成较好,也可适量使用。     

草鱼对27种饲料原料中氨基酸的表观消化率

本试验以0.5％Cr2O3为指示物,按照“70％基础饲料 30％试验原料“的饲料配制方法,在可控条件的室内循环养殖系统中用2龄草鱼种（体重150-200g）对常用的饲料原料的氨基酸表观消化率进行测定。试验选用了进口鱼粉、国产鱼粉、蟹粉、肉粉、肠衣粉、酵母、菜饼、黄菜粕、菜粕、双低菜籽粕、豆粕、膨化大豆、芝麻饼、棉粕、玉米胚芽粕、玉米蛋白粉和酒糟粉共17种商品蛋白质饲料原料,玉米、麦麸、次粉、米糠、标粉、小麦、大麦、玉米糟、稻谷、药渣共10种能量饲料原料,得到了每种原料的16种氨基酸的表观消化率。表观消化率主要规律表现为：草鱼对原料蛋白质消化率高时对氨基酸的总消化率也高,如对鱼粉、豆粕的消化率高;对玉米类原料如玉米蛋白粉、玉米渣、玉米的氨基酸消化率较低,而对小麦类原料如小麦粉、麦麸、次粉等的消化率相对较高;在植物饼粕类中,草鱼对豆粕和菜粕的消化率较高,而对棉粕的消化率则相对较低;对同种原料的16种不同的氨基酸的表观消化率也有很大的差异,这种差异的规律性较差。     

饲料中蛋白质和醣的含量对青鱼鱼种生长的影响

本文讨论了饲料中蛋白质和醣含量对青鱼鱼种生长的影响。试验饲料由酪蛋白、糊精、鱼肝油、羧甲基纤维素粉(CMC)、无机盐混合剂和适量的维生素组成。用于试验的青鱼鱼种的平均体重为37．12—48．32克，试验期间的水温为24—34℃，试验得到的数据，经统计分析表明，青鱼鱼种饲料的最适蛋白质含量为29．54—40．85％。饲料中蛋白质和醣含量之间存在着明显的交互作用，当蛋白质含量为37—43．3％，醣含量为9．5—18．6％时，青鱼鱼种生长最快。饲料的蛋白质含量对鱼体的蛋白质、脂肪和醣含量有一定影响，肝脏中蛋白质含量也受到饲料蛋白质含量的影响，肝醣含量则随饲料醣含量的增加而增加。饲料中蛋白质和醣的含量会影响青鱼鱼种的消化率，当饲料中蛋白质处于最适量而醣含量在30％以下时，鱼的蛋白质消化率大致为92％左右，醣含量过高将对蛋白质的消化率产生影响。饲料的组成对青鱼鱼种的血红蛋白含量影响不大。     

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).     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

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.