安普霉素对仔猪养分代谢率及氮沉积的影响

20头28日龄大长北三元杂交断奶仔公猪随机分为4组,分别饲养于不同环境温度(28℃、15℃)下的代谢笼内,饲喂含有不同剂量安普霉素(0、90、150mg/kg)的日粮,试验期为2周,后7d进行全收粪代谢试验,观测安普霉素对仔猪物质表观代谢率及氮沉积的影响。研究结果表明,在低温环境下日粮中添加安普霉素可抵御寒冷应激,改善仔猪日粮干物质和蛋白质的表观代谢率,增加机体氮的沉积,其中150mg/kg安普霉素可显著提高仔猪日增重70.5%(P<0.05)、改善饲料转化率32.7%(P<0.05),并能提高采食量、降低发病死亡率。在低温环境下,应适当加大抗生素的添加剂量。     

“葛根芩连口服液”对仔猪白痢的临床药效试验

通过口服给予葛根芩连口服液，评价其对哺乳期仔猪白痢的临床治疗效果。试验结果表明，按高0．20mL／（kg体重）、中0．10mL／（kg体重）、低0．05mL／（h体重）3个剂量口服，2次／（1，连用5d，对临床仔猪白痢具有较好的治疗效果．治愈率分别为90．91％、89．28％和56．25％；有效率分别为95．45％、92．85％和68．75％。其中，高、中剂量组与恩诺沙星组的治疗效果最好，三者之间差异不显著（P〉0．05）；明显高于低剂量组与痢茵净组（P〈0．05）或P〈0．01）。     

饲料中添加碘提高断奶仔猪生长性能

长江大学动物科学学院程泽信等，选用长大二元杂交断奶仔猪36头，随机分为3组，每组12头，试验1、2组的仔猪分别饲喂在基础日粮中添加2．8mg/kg、1．4mg/kg碘的饲料，对照组仔猪饲喂基础日粮，试验期为30d．结果表明：试验1组和试验2组的试验末重均比对照组高，且差异显著（P〈0．05），试验1组和试验2组的平均日增重比对照组高，饲料利用率也优于对照组；在经济效益方面．试验1组及2组分别比对照组提高了14．9％和13．1％。     

纳米蒙脱石替代氧化锌提高断奶仔猪生产性能

华南农业大学动物科学学院王修启等，选取84头体重相近的二元杂交断奶仔猪，随机分为3个处理组，每个处理组4个重复，每个重复7头（公母比例为4：3），各个重复统计检验差异不显著。处理1（对照组）饲喂基础日粮，处理2（氧化锌组）和处理3（纳米蒙脱石组）分别在基础日粮中添加3000mg／kg氧化锌和3000mg／kg纳米蒙脱石，试验期为28d，结果表明，     

三种铬源对育肥绵羊生产性能及免疫功能的影响

本试验选择5月龄道寒杂交绵羊28只，随机分成7组，每组4个重复，每个重复1只羊，试验期为60d。研究在日粮中分别添加0．2mg／kg、0．4mg／kg的无机铬（三氯化铬），烟酸铬，酵母铬对育肥绵羊生产性能、免疫功能的影响。研究结果表明：（1）日粮中添加铬后，在一定程度上提高了育肥绵羊的生产性能，增强了免疫功能；（2）三种铬源对热应激状态下绵羊免疫功能有显著影响。补充0．4mg／kg三种铬源组绵羊脾脏指数，血清IgA、IgM、JgG含量显著高于对照组和0．2mg／kg组。本试验表明：三种铬源对增强绵羊免疫功能，提高抗应激能力均是有效的。建议添加量为0．4mg／kg。     

甘氨酸铁络合物髓提高母猪和乳猪的生产性能

北京养猪育种中心马艳凤等，选用36头28日龄断奶、长大二元杂交健康仔猪，按窝别和体重随机分为3组，分别饲喂基础日粮、糙米替代50％玉米日粮、糙米替代70％玉米日粮．试验结果表明，饲粮50％、70％被糙米替代，断奶仔猪日增重分别提高了163％、19．7％（P〈0．01），饲料转化率降低4．7％、8．2％（P〈0．01）；回肠、盲肠大肠杆菌数随日粮糙米含量的增加而下降，     

灰树花多糖对鲫鱼免疫功能的影响

以灰树花多糖（Polysaccharide of Grifola frondosa，PGF）药饵连续投喂鲫鱼35d，通过测定血清凝集抗体效价、超氧化物歧化酶（Superoxide dismutase，SOD）活性、离体白细胞吞噬活性（phagocytic activity）、吞噬细胞杀菌活性（bactericidal activity），研究灰树花多糖对水产动物特别是鲫鱼免疫功能的影响。试验设计以不同剂量（分别为250mg／kg鱼体重、400mg／kg鱼体重、500mg／kg鱼体重、600mg／kg鱼体重、1000mg／kg鱼体重）的灰树花多糖药饵饲喂试验鲫鱼，分别于第0、7、14、2l、28、35d用血凝板法、MTT染色法进行免疫学指标测定。结果表明，各添加水平均可增强鲫鱼的免疫功能，其中剂量为400mg／kg、500mg／kg和600mg／kg的吞噬活性及杀菌活性与对照组相比存在极显著性差异（P〈0．01），而剂量为250mg／kg、1000mg／kg时，杀菌活性均与对照组相比存在显著性差异（P〈0．05）；400mg／kg组、500mg／kg和600mg／kg组的SOD活性与对照组相比存在极显著性差异（P〈0．01）；400mg／kg组、500mg／kg和600mg／kg组的血清凝集抗体效价最高为1：256，250mg／kg和1000mg／kg组的血清凝集抗体效价最高为1：32。各项指标的峰值出现在第2～3周。     

酪酸菌能明显提高猪生长的特性

周口职业技术学院王保正等，在哺乳仔猪教槽料中提前添加酪酸菌，仔猪断奶时试验组与对照组的头均增重无明显差异（P〉0．05），料重比试验组明显低于对照组（P〈0．05），育成率试验组极显著（P〈0．01）高于对照组；断奶后至转群时试验组的头均日增重和头均增重明显（P〈0．05）高于对照组，而试验组的料重比又明显（P〈0．05）低于对照组；达90kg的出栏日龄试验组比对照组提前8．1d，     

司粮中铬添加水平时海兰褐种公鸡繁殖性能的影响

试验选用10周龄时个体发育良好．冠髯大而鲜红的海兰褐种公鸡907,,随机分为6组,每组15只。CK组为对照组,饲喂基础日粮,在Ⅰ、Ⅱ、Ⅲ、Ⅳ和Ⅴ组日粮中分别添加0．2、0．4、0．6、0．8和1．0mg／kg的铬,以此来研究铬对种公鸡繁殖性能的影响。研究结果表明,种公鸡饲粮中铬的添加量在0．2-0．8mg／kg时,随着添加量的增加．体重、第二性征及性腺的发育均趋于增加趋势,对提高体重、性腺发育及繁殖性能有极显著影响（P〈0．01）,铬添加水平达1．0mg／kg时平均射精量、受精率、精子密度及精予活力均逐渐呈减弱趋势,而畸形率则呈增长趋势,该组与CK组比较差异极显著（P〈0．01）。综合分析,日粮中理想的铬添加量是0．8mg／kg,可有效地提高海蓝褐种公鸡的繁殖性能。     

乙腈对自然水域的污染及氰化物毒性的消解试验

乙腈为含氰的有机化合物（甲基腈），对水域中鱼类有极强的毒杀作用。2006年对受其污染的安达市富来湖5处水样进行了检测和鱼类存活试验。检测方法是：异烟酸一吡唑啉酮比色法。氰化物浓度分别是：安01#0．018mg／L；安02#0．019mg／L；安03#0．067rag／L；安04#0．042mg／L；安05#0．009mg／L。均超出GB／T7486．1987标准≤0．005mg／L标准量。其中污水放口最高，超标134倍。鱼类在三组水样中情形不同：原水样的A组安05#内，鱼类存活18h。加入渔业用漂白粉的B组鱼反应剧烈，存活时间明显缩短，除B组安05#外均不超过1h。加入渔业用硫酸铜的C组（0．7mg／L），鱼类存活时间均超过12h，最长的C组安05#96h成活100％。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

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 performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

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).     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.     

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.     

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.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.