大蟾蜍卵孵化的温度效应研究

为了解大蟾蜍卵的孵化率、发育起点温度、发育有效积温和蝌蚪成活率,将产出当天的大蟾蜍卵采集回实验室,分别置于5个不同温度(10℃、15℃、20℃、25℃和30℃)下孵化,观察和测量记录卵的孵化率、孵化后3 d蝌蚪的成活率、体长及每个温度下卵的发育历期。光照周期设为14L∶10D。结果表明:温度对大蟾蜍卵的孵化率影响显著;孵化后3 d蝌蚪的成活率随着温度的升高而降低,30℃下孵化的蝌蚪在2 d之内全部死亡;温度对大蟾蜍卵孵化后3 d蝌蚪全长的影响极显著(F=55.592,df=4,N=50,p<0.000 1),大蟾蜍的卵孵化后3 d蝌蚪的全长随着温度的升高而增加;应用直线回归法和直接最优化法算得的大蟾蜍卵的发育起点温度和有效积温分别为0.35℃、68.64℃/d和0.15℃、69.29℃/d。     

6种石斑鱼成鱼的性腺发育、脑垂体结构以及垂体中FSHβ和LHβ细胞的免疫识别

以日本海域捕获的宝石石斑鱼(Epinephelus areolatus)、黑边石斑鱼(E.fasciatus)、赤点石斑鱼(E.akaara)、尾纹九棘鲈(Cephalopholis urodeta)、蜂巢石斑鱼(E.merra)和纹波石斑鱼(E.ongus)成鱼为对象,比较其性腺发育和脑垂体结构以及垂体中FSHβ和LHβ免疫信号的分布。结果表明:宝石石斑鱼、黑边石斑鱼、赤点石斑鱼和尾纹九棘鲈性腺发育为未成熟阶段,蜂巢石斑鱼和纹波石斑鱼性腺发育为成熟阶段。6种石斑鱼的脑垂体位于间脑腹面,由神经垂体(NH)和腺垂体(AH)组成。腺垂体从左至右进一步细分为前外侧部(RPD)、中外侧部(PPD)和中间部(PI)。在宝石石斑鱼、赤点石斑鱼和纹波石斑鱼中NH结构被PPD隔开分为上下两部分,而在黑边石斑鱼、尾纹九棘鲈和蜂巢石斑鱼中NH为一个整体。6种石斑鱼脑垂体中FSHβ和LHβ细胞的免疫信号主要分布在PPD和PI区域,且FSHβ信号强度均较LHβ强,推断在石斑鱼性腺发育成熟前后,FSHβ较LHβ重要。为石斑鱼的资源保护及人工繁殖方面提供基础生物学资料和理论依据。     

基于增效剂与除草剂协同作用的豚草与三裂叶豚草的防控技术

【目的】增效剂与除草剂协同使用,研究筛选化学防治豚草与三裂叶豚草的减施增效技术过程中施用的最佳药剂用量。【方法】采用田间小区试验,以2种除草剂的田间适宜用药量作为减药基线,对比分析2种增效剂在减药15%、30%和50%水平下协同使用处理下豚草与三裂叶豚草的田间防治效果。【结果】在防治三裂叶豚草与普通豚草时,添加增效剂在减药15%、30%和50%水平下药后45或78 d株防效和鲜重防效整体较好的是激健,防效分别为64.23%~98.84%和65.37%~98.09%。2种除草剂在田间适宜用药量处理下药后45 d或78 d的株防效分别为99.24%、97.59%和100.00%、97.69%,在减药15%、30%水平下与增效剂激健协同施用处理的株防效分别为87.70%~98.65%和88.77%~97.96%,与田间适宜用药量的株防效相当,分别相差0.59%~11.54%和0.27%~11.23%;在减药50%水平下与增效剂激健协同施用处理的株防效分别为54.30%~67.00%和55.63%~67.14%,低于田间适宜用药量的株防效,分别相差30.59%~44.94%和30.55%~44.37%。【结论】21%氯氨吡啶酸AS 17.50 mL/667m²、75%苯嘧·草甘膦WG 42.00 mL/667m²,合理添加增效剂可有效控制5月约6叶期株高为23 cm左右的三裂叶豚草和6月约8叶期株高为12 cm左右的豚草的发生与为害,减施30%可行,不同增效剂之间的增效作用存在一定差异。增效剂推荐使用激健15.00 mL/667m²,其次青皮桔油15.00 mL/667m²。     

基于MaxEnt模型和GIS空间技术对大熊猫在岷山地区的时空变化分析及预测

大熊猫是国家Ⅰ级保护野生动物,是全世界珍稀动物的旗舰保护物种。经过历史环境的不断演变,野生大熊猫不仅仅在食性上由食肉转变为食竹,而且其个体形态、行为和生理等方面也有一定改变。由于大熊猫种群数量的稀少和习性的改变,相关保护工作和科学研究更具意义。近年来,在全球气候变化的大背景下,人类制定科学的保护计划来减轻大熊猫生境破碎化。基于大熊猫繁殖生境分布较为破碎和大熊猫种群数量较少,本研究从生态学角度研究大熊猫与环境之间的关系。通过MaxEnt模型和GIS空间技术对岷山地区大熊猫栖息地的时空变化分析及21世纪50、70年代栖息地范围预测,揭示大熊猫分布区与气候环境因素、坡度、植被和海拔等因素的相关性。结果表明,受试者操作特征曲线面积均超过0.9,显示模型建立准确性“极好”,且都具有统计学意义。野生大熊猫在岷山地区的适宜栖息地集中在中低海拔（2 500~3 000 m）、年平均温度（6~7℃）适宜、降水量（800 mm）丰富的温性针叶林和常绿阔叶林。野生大熊猫分布的主要影响因素为BIO15,并且大熊猫生境最适宜生存的区域在岷山片区明显向南偏移。从时间和空间的角度,对岷山片区大熊猫适宜生境进行动态分析,预测出不同情景下未来最适宜生存区域,为岷山片区内的自然保护地分布及管理提供科学信息。     

Influence of feeding regime on fatty acid composition in young red-spotted grouper Epinephelus akaara

ABSTRACT:   Young red-spotted grouper Epinephelus akaara with an average total length of 3.4 cm were divided into five groups in floating net-cages, and reared under satiated conditions with different feeding frequencies (0.5, 1, 2, 4 and 8 times per day) for 40 days. Total food intake increased with feeding frequency. Feeding four times per day resulted in the highest growth and food conversion efficiency. Total lipid accumulation in the muscle, liver and intraperitoneal fat body (IPF) increased with feeding frequency. Red-spotted grouper were found to contain a high proportion of docosahexaenoic acid (DHA) in the muscle. Fish fed 0.5 times per day were characterized as having a high proportion of DHA in triglycerides (TG) in muscle (80%), liver (69%) and IPF (18%). Increasing saturated fatty acids and a relative reduction of DHA were observed in the muscle TG as the feeding frequency increased. Frequent feeding accelerated the accumulation of eicosapentaenoic acid and saturated acids in the liver and IPF. Low saturated acids and a subsidiary proportional increase in DHA were the result of the low lipid reserves. A possible role for DHA and saturated acids are discussed with regard to lipid reserves.     

Biological and ecological traits of Bathynomus giganteus and Bathynomus miyarei (Crustacea: Isopoda): Contribution to the conservation of deep-sea in southern Brazil

1. This study aimed to determine biological and distributional aspects of deep-sea giant isopods Bathynomus giganteus and Bathynomus miyarei to assess their extinction risk.
2. Bathynomus giganteus (663 specimens) and B. miyarei (649 specimens) were collected during five research cruises involving 265 h of sampling effort during 32 fishing operations of circular pots, baited traps, ranging from 400 and 1,000 m deep, between 26 and 29°S adjacent to the Brazilian coast.
3. A trend towards larger, sexually mature animals in shallower regions was observed for both species, and depth was the most important environmental variable influencing the animals’ distribution.
4. Bathynomus giganteus were collected between 600 m and 1,000 m depth, while the highest densities of B. miyarei were at shallower depths, between 400 and 600 m.
5. The sex ratio was equal for both B. giganteus and B. miyarei for different seasons, latitudes and bathymetries.
6. The sexual maturity of B. giganteus was estimated at 340–345 mm total length for males and between 280–290 mm for females. Bathynomus miyarei males’ sexual maturity was estimated in the 225–230 mm size class.
7. Bathynomus giganteus showed reproductive activity throughout the year.
8. The longevity of B. giganteus was estimated at 6 years for males and 7.7 years for females. The longevity of B. miyarei was estimated at 9 years for males and 6 years for females.
9. Extinction risk assessment for B. giganteus, which has a greater latitudinal and bathymetric distribution, was evaluated as Least Concern. However, B. miyarei was evaluated in the Data Deficient category.

     

壳寡糖对虎龙斑的生长、免疫及肠道菌群的影响

壳寡糖（Oligochitosan,OCS）,作为绿色饲料添加剂,具有许多重要的生物活性功能,如促进生长、抗氧化等,但对石斑鱼免疫调控机制的研究还未解读。本试验通过在基础试验饲料中添加0（对照组）、100、200、400、800、1600 mg/kg的壳寡糖,配制出5种试验饲料并投喂虎龙斑（Epinephelus fuscoguttatus ♀× Epinephelus lanceolatu ♂）4周后,分析饲料中添加壳寡糖对虎龙斑的生长、非特异性免疫、肠道菌群多样性以及抗病力的影响。结果显示：（1）壳寡糖能显著提高石斑鱼的增重率、降低饲料系数,但对肥满度和存活率无显著影响。（2）采用实时荧光定量PCR（qRT-PCR）技术对虎龙斑中肠的免疫基因表达进行检测,结果显示壳寡糖可显著提高免疫相关基因表达水平（p < 0.05）,激活炎症因子TNF-α、IL-1β、TGF-β1、TOR、TLR3的表达,提高GPx、CAT、MnSOD的表达来改善抗氧化能力,并增加紧密连接蛋白ZO-1、ZO-2、ZO-3、Claudin-3α的表达。（3）通过微生物组高通量测序来揭示壳寡糖投喂石斑鱼的肠道微生物群落结构,结果表明,实验组和对照组肠道细菌优势类群丰度和α多样性无显著差异（p > 0.05）;但是800 mg/kg组的益生菌所占丰度增加,细菌群落β多样性差异明显,可改变其群落组成结构。（4）以哈维氏弧菌（Vibrio harveyi）攻毒7 d后,800 mg/kg组的累积死亡率显著低于对照组和其他实验组（p < 0.05）,并显著改善肠道形态。综上所述：饲料中添加适量的壳寡糖能促进虎龙斑的生长、提高免疫力、改善肠道菌群及增强抗病力。     

大鲵肌肉及其天然饵料营养成分的比较研究

大鲵Megalobatrachus davidianus(Blanchard),俗名娃娃鱼,是我国现存的唯一一种大型两栖动物,并被列为我国的第二类保护动物。其肉质细嫩、鲜美,并有较高的药用价值,是特种水产品养殖的良好品种。但长期以来,国内外对大鲵的研究,多集中在外部形态观察、系统解剖分析、生态及资源调查,未进行过营养方面的研究,而要保护并利用大鲵资源,进行人工养殖,对大鲵及其天然饵料营养方面的了解是不可缺少的,因此开展大鲵肌肉及其天然饵料营养成分比较研究,对保护和利用大鲵资源具有一定的意义。     

Effects of dissolved oxygen on hemolymph parameters of freshwater giant prawn, Macrobrachium rosenbergii (de Man)

Profiles of changes in physiological parameters of freshwater giant prawns, Macrobrachium rosenbergii, exposed to various dissolved oxygen (DO) levels of 7.75, 4.75, 2.75, and 1.75 mg l⁻¹ are reported. The parameters involved in osmoregulation and oxygen transport were monitored for a 6-day period. Notable depressions in hemolymph osmolality, Na⁺, K⁺, and Cl⁻ contents were observed within 24 h after exposure to hypoxia at 2.75 and 1.75 mg O₂ l⁻¹, and thereafter remained at rather steady levels, which were significantly lower than those under normoxic conditions (4.75–7.75 mg O₂ l⁻¹). The extent of depression of osmotic-related constituents, hemolymph osmolality and Cl⁻ in particular, increased with decreased DO.

Oxyhemocyanin constituted 65.46–65.84% of total hemolymph proteins under the various DO levels examined; both hemolymph oxyhemocyanin and proteins showed notable elevations 24 h after exposure to hypoxic conditions, and reached the highest and constant level by 48 h after exposure. The compensatory responses of prawns to reduced O₂ were manifested by increased O₂ uptake through augmentation of hemocyanin, which results in enhancement of oxygen binding capacity of the hemolymph. In the same period, a significant surge of the respiratory products, PCO₂ and HCO₃⁻, was also demonstrated 6 h after exposure to hypoxic conditions which resulted in hemolymph alkalosis. These processes likely resulted in an increase in water influx and consequent declines in hemolymph osmolality and ion composition. Furthermore, hyperventilation and respiratory alkalosis, indicated by increased oxyhemocyanin and pH, respectively, were found to be predominant responses of M. rosenbergii to hypoxic stress.     

Ontogeny of digestive and immune system organs of larval and juvenile kelp grouper Epinephelus bruneus reared in the laboratory

ABSTRACT:   A histological examination was made of the ontogenetic development of the digestive and immune systems of the larval and juvenile kelp grouper Epinephelus bruneus reared in the laboratory. The liver, gall bladder, pancreas and the demarcating region between the intestines and rectum were formed within 3 days post-hatch (dph). During the preflexion phase (within 16 dph), revolution of the intestine concluded, and pharyngeal teeth and the mucous cells of the esophagus were differentiated. In the transitional period to the juvenile stage (25 dph), the blind sac of the stomach, gastric glands and pyloric caeca began to form. From the viewpoint of the differentiation phase of the adult-type digestive system, the kelp grouper is similar to Heterosomata, hitherto reported. The primordial thymus, kidney and spleen were present at 12, 1 and 6 dph, and the small lymphocytes in these lymphoid organs appeared at 21, 30 and 33 dph, respectively. The developmental sequence of the lymphoid organs and the appearance ages of the lymphoid organs and small lymphocytes in the lymphoid organs in the kelp grouper are similar to those of other marine fish previously reported, except for the Pacific bluefin tuna Thunnus orientalis .