木醋液对桃蚜生长繁殖的急慢性效应

为了明确木醋液对桃蚜短、长期影响,以桃蚜为试虫,用100倍稀释木醋液处理小白菜饲养蚜虫,测得桃蚜繁殖发育数据。结果显示,木醋液处理显著缩短桃蚜繁殖期,而F₁代繁殖期比F₀代繁殖期延长37%;F₀代和F₁代产蚜总量与对照组相比分别降低62%和66%;处理组F₁代和F₂代的存活率比对照组降低23%和24%,但F₁代和F₂代之间差异不显著;F₁代寿命缩短25%,F₂代差异不显著。本研究证明木醋液能够缩短桃蚜的繁殖期,延长其若蚜历期,整体缩短桃蚜寿命,降低子代存活率。总之,木醋液对桃蚜的生长发育和繁殖具有一定的抑制作用,但是这种抑制作用会随着施用频次增加而逐渐减弱,即木醋液的短期效应和长期效应存在差异,所以木醋液具有开发为生物农药的价值。     

豫皖小麦田麦根腐平脐蠕孢交配型基因检测

麦根腐平脐蠕孢是一种可以引起多种植物病害的病原真菌，广泛分布于世界各地，对全世界的禾谷类作物生产带来了不可估量的损失。子囊菌交配型基因具有一定的广泛性，其编码的产物是调控子囊菌有性生殖的重要转录因子。为了对河南、安徽小麦田分离获得的麦根腐平脐蠕孢群体的MAT基因型进行探索，对在河南、安徽两省不同地区分离获得33株麦根腐平脐蠕孢菌株，利用麦根腐平脐蠕孢菌的MAT特异性引物进行基因型检测，并对不同交配型代表菌株进行生长形态、孢子形态观察和致病力测定，对麦根腐平脐蠕孢菌 MAT-2基因进行了系统发育分析。结果表明，河南、安徽两省存在两种MAT基因型的麦根腐平脐蠕孢群体，含有 MAT-2基因的菌株21株，含 MAT-1基因的菌株12株，比例为7∶4（ MAT-2∶ MAT-1）。两种交配型菌株的生长形态、孢子形态和致病力无显著差异，整体分析结果与物种的分子系统学分析表现出来的亲缘关系基本一致。     

Nile tilapia broodfish fed high‐protein diets: Digestive enzymes in eggs and larvae

The aim of this study was to assess the activity of gastric, pancreatic and intestinal digestive enzymes during the embryonic and larval development of Nile tilapia (Oreochromis niloticus) GIFT strain Aqua America^® 1 obtained from a broodstock fed two levels of crude protein (CP). A total of 72 females and 24 males, 10 hapas, two CP levels (32% and 38%) and six phases of embryonic (cleavage, blastula, gastrula) and larval (hatching, 7 and 10 days post hatch, dph) stages were used. The eggs were collected in cleavage, blastula and gastrula stages, 300 mg was collected, and kept in cryogenic tubes in liquid nitrogen. For the samples at larval stage, the remaining eggs were separated according to crude protein level and kept in hatcheries and samples were collected on 7 and 10 dph the same way as before. A total of 48 samples were collected: at each protein level (32% and 38% CP), four samples were collected in each phase of embryonic and larval development. Statistical differences were not observed during embryonic development for acid proteases, trypsin, amylase and lipase activity at both levels of crude protein (32 and 38% CP). Differences for acid proteases were noticed on 7 dph; trypsin and amylase on 7 dph and 10 dph. Significant differences on blastula and 7 dph for protease; as for aminopeptidase, there was significant difference on 7 dph. The data indicated early appearance of digestive enzymes in Nile tilapia broodfish receiving 32% CP taking into account the rapid growth and development of this species.     

不同温度下豇豆花粉对卵圆真绥螨发育及繁殖的影响

为探讨不同温度下豇豆花粉对卵圆真绥螨[Euseius ovalis(Evans)]发育及繁殖的影响，在温度条件为25、30、35 ℃下，用豇豆花粉饲喂卵圆真绥螨，观察雌成螨繁殖，记录卵至成螨的发育历期，分析各螨态存活率及各生命参数。结果表明，用豇豆花粉饲喂卵圆真绥螨在3种温度下均可正常发育和繁殖，单雌总产卵量分别为(32.33±2.17)、(19.29±2.85)、(10.40±1.92)粒。卵-成螨30 ℃时发育历期最短，为(3.71±0.12) d。卵-成螨在25、30 ℃下存在较高的存活率，分别为93.75%±4.35%、90.63%±5.24%，35 ℃时存活率最低，为68.75%±8.30%。说明豇豆花粉可作为卵圆真绥螨的交替食物。35 ℃时，卵圆真绥螨的净增殖率、内禀增长率和周限增长率均为最低，分别为1.45±0.13、0.04±0.03和1.04±0.02，与25、30 ℃时存在显著差异，说明高温对卵圆真绥螨存在抑制作用。30 ℃种群加倍时间最短，为(3.73±0.56)d。     

Assessment of short-term mortality of granary weevil,Sitophilus granarius (Coleoptera: Curculionidae) triggered by different microwave irradiation powers

Abstract

The insecticidal efficacy of microwave irradiation against the at 12, 24, 48 and 72?h following exposure to microwave irradiations (100, 300?W) and the progeny production was assessed 45?days later. Linearly increasing irradiation power range (100, 200 and 300?W) was set up for determining mortality tendency. An increase of insect mortality caused by higher irradiation period and times elapsed after treatment has become evident commencing from 12?h after the treatment, which has significantly decreased at later elapsed time after treatment. The irradiation periods inducing the highest mortality at the examined powers were at 10?min and at 100?W power (72?h: 64.93%) and at 4.5?min. and at 300?W power (12?h: 87.01). In addition, a complete suppression of progeny production was achieved by 4.5?min treatment at 300?W power. Lognormal-type mortality process was caused by the linearly increased irradiation range. The properly chosen microwave irradiation can be used for management of Sitophilus granarius larval and adult developmental stages. This treatment could provide an effective and friendly environmental treatment technique in Integrated Pest Management (IPM) program.     

Effects of the prebiotic mannan‐oligosaccharide on feed deprived zebrafish: Growth and reproduction

This study was designed to investigate whether the prebiotic mannan‐oligosaccharides (MOS) can reduce the deleterious impacts of feed deprivation on growth and reproduction in zebrafish. In the growth performance experiment, juvenile fish were distributed in the following four treatments: normal‐control (NC), starved‐control (SC), normal‐prebiotic (NP) and starved‐prebiotic (SP). After 8 weeks, NP and SC fish showed the highest and lowest growth patterns, respectively among treatments. Standard length, specific growth rate and feed conversion ratio did not differ significantly between NC and SP treatments. Autochthonous lactic acid bacteria (LAB) were significantly higher in NP and SP than the NC and SP treatments. Feed restriction resulted in significantly lower concentrations of thyroxine. In the reproductive performance experiment, additional juveniles were fed as in the growth experiment. Crossing in the final week of the experiment resulted in successful spawning in only NP fish, which showed mature sperm and oocytes in histological examinations. The number of spermatozoa was significantly lower in the fish that experienced feed restriction; however, the oocytes of SP females were at the same maturation level to that observed in NC females. Sex‐steroids changed after both starvation and MOS supplementation where NC and SP showed no differences in the levels of testosterone and female's 17β‐estradiol. These results indicate that MOS supplemented diet reduced some side effects of feed deprivation (final weight and length, SGR, FCR and levels of LAB and T3), and suggest that supplementation of the diet with MOS may ameliorate some of the negative effects of feed deprivation in zebrafish.     

Effect of ascorbic acid supplementation on zootechnical performance,haematological parameters and sperm quality of lebranche mullet Mugil liza

The feed provided to breeding fish is one of the main factors influencing the quality of fish gametes. This study was carried out to evaluate the influence of ascorbic acid on growth, haematological parameters and sperm quality of Lebranche mullet males (Mugil liza). Six diets with different levels of ascorbic acid (0; 53; 107; 216; 482 and 708 mg/kg) were tested in triplicate for 75 days. During spermiation (first gonadal maturation), 144 individuals (205.7 ± 11.5 g and 25.7 ± 0.4 cm) were randomly distributed in 18 experimental tanks. Growth parameters were evaluated at the beginning and end of the experiment. Fish blood was collected to analyse glucose, total protein and erythrocyte count (EC) (n = 9). Fish (n = 12) from each treatment were euthanized to determine hepatosomatic index (HSI) and gonadosomatic index (GSI). Semen was collected to evaluate spermatic density, cell membrane integrity and sperm motility. No difference (p > .05) was found on growth parameters, GSI, HSI and total protein. However, EC was lower in fish fed without ascorbic acid (the control group). Ascorbic acid supplementation provided positive effects on sperm characteristics. Fish from treatments with 53 and 107 mg/kg presented the best results for motility time (133.30 ± 4.25 and 135.00 ± 2.77 respectively). Treatments with 107, 216 and 708 mg/kg provided the best results for motility rate (92.0 ± 2.9%, 93.0 ± 5.8% and 93.0 ± 5.8% respectively). Supplementation with 107 and 216 mg/kg provided the best results for plasma membrane integrity (70.12 ± 9.10% and 76.3 ± 3.1% respectively). Lower spermatic density was observed in fish without ascorbic acid supplementation, although no difference was found in sperm density among the treatments with ascorbic acid (p < .05). Considering these results, supplementation of dietary ascorbic acid between 107 and 216 mg/kg optimizes the spermatic quality in males of lebranche mullet.     

Possible involvement of PKC/MAPK pathway in the regulation of GnRH by dietary arachidonic acid in the brain of male tongue sole Cynoglossus semilaevis

Our previous studies have indicated that dietary arachidonic acid (ARA) significantly affects the gonadal steroidogenesis in the marine teleost tongue sole Cynoglossus semilaevis, and this effect was more positive in male fish than in female fish (Aquaculture, 468, 378–385). As a following up study, the present study was further aimed at investigating the possible mechanisms in the brain mediating the effects of dietary ARA on gonadal steroidogenesis. A 70‐day feed trial was repeated with two‐year‐old tongue sole, using three experimental diets with graded levels of ARA, 0.34%, 2.53%, and 9.63% of total fatty acids. Each diet was fed to triplicate groups of 23 fish (15 males and 8 females). The results confirmed the positive effect of dietary ARA on testosterone production in male fish. The concentration of gonadotrophin‐releasing hormone (GnRH) in serum responded to dietary ARA in a similar pattern with the testosterone concentration, but the concentration of gonadotrophin in serum was not affected by dietary ARA. The response of gene expression of PKCβ, ARRB1, ARRB2, ERK2 and ATF3 in the brain to dietary ARA was in good agreement with those of GnRH and testosterone, indicating the possible involvement of PKC‐ARRB‐ERK‐ATF3 pathway in signalling transduction of GnRH. However, the PI3K/Akt and TLR/NF‐κB pathways may not be directly involved in the regulation of GnRH metabolism by ARA. This is the first study reporting the possible involvement of PKC/MAPK pathways in regulation of reproductive endocrine processes by long‐chain polyunsaturated fatty acid in brain of marine fish.     

土壤施用生物质炭对取食水稻的灰飞虱生活史特征的影响

【目的】为评价土壤施用生物质炭在防治农作物害虫中的潜力,观察了土壤施用生物质炭对取食水稻的灰飞虱(Laodelphaxstriatellus)发育和生殖的影响。【方法】开展室内盆栽试验,采用生物质炭种类(玉米、水稻和小麦秸秆)与添加量（0、30和50g/kg）的2因素×3水平组合处理土壤,种植水稻苗、接种灰飞虱,观察灰飞虱的发育和生殖表现。【结果】1)生物质炭种类与添加量互作影响灰飞虱若虫历期,当施用玉米或水稻生物质炭时,不同添加量之间的若虫历期无显著差异;当施用小麦生物质炭时,添加30g/kg生物质炭处理下的若虫历期比对照(18.70±0.30 d)延长1.54 d。2)生物质炭种类与添加量没有显著互作影响雌成虫寿命。添加量不影响,但生物质炭种类具有显著影响,施用玉米或小麦生物质炭处理雌成虫寿命比水稻生物质炭处理雌成虫寿命(23.70±0.48d)分别延长2.13 d或3.10 d。3)生物质炭种类与添加量互作影响灰飞虱雌虫终身产卵量,施用生物质炭使生殖力下降,但下降幅度随生物质炭处理不同而异,当添加30g/kg生物质炭时,施用玉米生物质炭处理下的雌虫终身产卵量(176.40±6.84粒)比施用水稻或小麦生物质炭处理分别多22.80粒或18.95粒;当添加50g/kg生物质炭时,施用玉米生物质炭处理的雌虫终身产卵量(140.30±3.26粒)比施用水稻或小麦生物质炭处理分别少16.90粒或21.60粒。【结论】施用生物质炭可减弱灰飞虱的生殖力,减幅随生物质炭种类与添加量的不同而异。     

Effects of selective cutting and herbicide use in spring barley on seed production of Cirsium arvense

A field experiment was performed in Sweden to evaluate the effect of herbicide treatment and selective cutting on the seed production of Cirsium arvense. Four treatments (control (C), selective cutting (S), early (H1) and late (H2) herbicide application) were laid out in a randomized block experiment. The field was sown with spring barley and contained a natural population of the weed. Treatments were first applied 2015 and repeated 2016. Changes in the number of seeds per flower receptacle and average seed weight were measured over time in 2016 from the onset of seed production until crop harvest. At harvest, number of shoots per area and cumulative numbers of flower receptacles, which had shed mature seeds over the season, were counted. These data were used to assess total seed production over the season. Treatment H2 led to a significantly decreased number of seeds per receptacle (49) compared to S (59), H1 (64) and C (67). Over time and treatment, number of seeds per flower receptacle was lowest in the second week (47) and increased over the third week to 69 in week four. Average weight per seed was about constant over time (0.91?mg) while H1 and S (0.63 and 0.78?mg, respectively) had lower seed weights compared to H2 and C (1.04 and 1.19?mg, respectively). Total seed production over the season in terms of number of seeds per square meter was greatly reduced by all treatments (5–20 seeds m^?2, or 3–14?mg?m^?2) compared to the control (6600 seeds m^?2, or 7800?mg?m^?2). We conclude that seed production of C. arvense is inhibited a thousand-fold and equally well by selective cutting as by early or late herbicide treatments.