松材线虫扩散型四龄幼虫向成虫转型发育阶段研究

通过光学显微镜观察松材线虫Bursaphelenchus xylophilus扩散型四龄幼虫(DL4)转型的形态结构变化过程以及油红染色后脂肪的特征变化,分析了不同植物对于转型过程的影响。结果表明:松材线虫由扩散型四龄幼虫向成虫转型分为5个阶段,定义为DL4,转型前期(TP),转型中期(TM),转型后期(TA)和转型末期(TT)。DL4阶段,头部钝圆,无溢缩,尾部较尖,无性别特征;TP阶段,线虫呈现竖直状态,可见头部蜕皮,出现口溢缩,尾部膨大;TM阶段,蜕皮明显,线虫开始弯曲,出现不显著的性别特征;TA阶段,进一步完成蜕皮,成虫状态表现明显,雌虫出现阴门盖,雄虫出现交合刺;TT阶段完成蜕皮。DL4时期脂肪含量最高,占据线虫全部身体;而转型前期则脂肪含量迅速下降,仅有头、尾和体表内侧较高;转型中期、后期和末期脂肪含量较少,脂肪颗粒化明显。松科植物红豆杉Taxus chinensis、圆柏Sabina chinensis、侧柏Platycladus orientalis、雪松Cedrus atlantica、油松Pinus tabuliformis、黑松Pinus thunbergii和马尾松Pinus massoniana促进转型效果明显,以黑松和马尾松木块刺激下松材线虫转型效率最高,而非松科植物银杏Ginkgo biloba无转型促进效果。     

Ontogeny of the digestive tract of Arapaima gigas (Schinz, 1822) (Osteoglossiformes: Arapaimidae) larvae

Early‐life survival of Arapaima gigas is one of the main challenges of its farming. In this study, we described the morphological and histochemical development of the gastrointestinal tract of arapaima larvae. Larvae were collected from a pond when they started to swim to the water surface (initial day) and were housed in indoor tanks. Daily samplings (n = 10) were performed from 0 to the 11th day after the collection (DAC) and then on the 14th, 17th, and 20th DAC. On the initial day, arapaima larvae (0.05 ± 0.01 g; 2.21 ± 0.06 cm) had opened mouth and anus and no yolk sac. In addition, larvae presented well‐developed digestive organs. Gastric glands were fully formed, with positive reactions to alcian blue (AB) pH 1.0 as well as to periodic acid‐Schiff (PAS) in the simple columnar epithelium. There were folds throughout the intestine and brush border, with an AB pH of 2.5 + PAS positive mucins. From 1 to 11 DAC, larvae presented increasing concentrations of gastric glands and thickness of the stomach muscular layer. From 14 to 20 DAC, the intestine presented high‐fold complexity. We suggest that arapaima larvae may be fed exogenous inert diets at a size of around 2 cm.     

Effects of dietary arachidonic and eicosapentaenoic acids on common dentex (Dentex dentex Linnaeus 1758) larval performance

Oily emulsions containing constant levels of total fatty acids (FAs) and varying eicosapentaenoic acid (EPA) and arachidonic acid (ARA) levels were used to enrich rotifers. Common dentex larval survival and growth were compared between groups fed different enriched live prey. Growth, survival rate, and lipid composition of larvae suggest that feeding common dentex in the first 15 days posthatching with 2.5–3% EPA, 6–8% docosahexaenoic acid (DHA), and DHA/EPA ratio of 2.0–2.5 is sufficient to fulfill their EPA requirements. Higher amounts of dietary EPA did not result in any significant improvement in growth or survival. EPA requirement during this period of larval development does not seem to be as critical as other FAs during the first 15 days of common dentex larval development, but it does not exclude its essentiality later in development. In the case of ARA, nutritional requirements are low compared to other marine finfish species, with the upper limit of this essential FA being around 2% of total FAs provided in the live prey composition.     

Effect of methoprene on the progeny production of Tribolium castaneum (Coleoptera: Tenebrionidae)

BACKGROUND: Tribolium castaneum (red flour beetle) is a serious insect pest of stored products around the world. Current control measures for this species have several limitations: loss of registration of insecticides, insecticide resistance and consumer concerns about chemical residues in food. The objective of this study was to determine whether methoprene affects progeny production of T. castaneum. Late‐instar larvae or young adults were exposed to methoprene‐treated wheat, and progeny production was determined. The pairing of male and female adults was performed as untreated × untreated, treated × untreated or treated × treated, to study sex‐based effects. RESULTS: There were three outcomes to late‐instar larvae held on methoprene‐treated wheat kernels (0.001 and 0.0165 ppm): (1) failure to emerge as an adult; (2) emergence as an adult, and almost no offspring produced; (3) emergence as an adult and normal production of offspring. Male larvae were more susceptible to methoprene than female larvae. In contrast, young adults exposed to methoprene (1.67–66.6 ppm) showed no reduction in offspring production. CONCLUSION: Methoprene concentrations will decline with time following its application. However, this research indicates that methoprene can still reduce populations of T. castaneum by reducing their progeny production, even if adults emerge. Copyright © 2011 Society of Chemical Industry     

羊狂蝇幼虫药物防治试验及最佳防治时间的选择

本文依据对我省黄河谷地的贵德县和高原腹地的玉树县两个不同海拔、气候地区羊狂蝇成蝇出现及消失时间等活动规律的观察结果,选用阿维菌素和伊维菌素药物的不同剂型,分别在9月上旬和10月中旬选择自然感染羊狂蝇幼虫的绵羊200只;采用注射液口服、泼背和片剂口服的方法,对羊狂蝇幼虫进行药物驱除的效果比较试验。结果表明:9月上旬驱虫组效果达100%,而10月份驱虫组效果不理想。     

柞蚕幼虫急性毒性试验研究

通过柞蚕幼虫的小鼠急性经口毒性试验,对柞蚕幼虫的食用安全性作出初步评价。结果表明:各组参试小鼠死亡数为零,未见中毒症状;雌、雄性小鼠MTD20.0g/kgBW,表明供试柞蚕样品属无毒级。     

Symblepharon secondary to ophthalmomyiasis externa in a dog

A 4-month-old crossbred female dog presented with complaints of poor vision and odd appearance of the eyes. At the age of a month, the animal was found lying in a railway road in a very bad condition and was rescued from death. At that time, the patient was presented with severe bilateral ocular discharge, and from both eyes, dipterous fly larvae were extracted. The dog was given symptomatic treatment (deworming, topical and systemic antibiotics, nutritional support) but never regained a normal eye appearance. At the time of the initial presentation, it had severe vision impairment because of bilateral cicatricial symblepharon, total in the left eye and occupying 3/4 of the cornea in the right eye. Surgery was proposed to attempt a resolution. Superficial keratectomy was performed in both eyes. After a midline incision in the cornea, the conjunctiva was dissected away. The conjunctiva was apposed to and sutured to the limbus and secured in the upper and lower conjunctival fornix. Additionally, in the left eye, a lateral canthotomy and canthoplasty were performed to enlarge the size of the eyelid opening. The corneal epithelium healed without complications, the patient regained vision, and after 36 months of follow-up, no recurrences were observed. To the authors' knowledge, this is the first report of symblepharon secondary to ophthalmomyiasis externa in a dog.     

Effects of probiotic bacteria on growth parameters and immune defence in Eurasian perch Perca fluviatilis L. larvae under intensive culture conditions

Two experiments were conducted to examine whether a mixture of bacteria composed of Bacillus licheniformis, Bacillus subtilis and Bacillus pumilus has a beneficial impact on survival, growth, lysozyme activity and total immunoglobulins (Ig) in perch larvae. In experiment 1, control fish were compared with fish receiving bacteria (4.93 × 10⁷ CFU L⁻¹ day⁻¹) through tank water or both through tank water and Artemia metanauplii enriched with two bacteria doses (2 × 10¹⁰ or 4 × 10¹⁰ CFU L⁻¹). Treatments were performed in 40 L triplicate tanks of 200 fish [initial body weight (IBW)=2.3 mg] each, placed in separated recirculating water systems. Experiment 2 evaluated the combining effects of bacteria feeding and densities (10 vs. 20 fish L⁻¹, IBW=9.5 mg). In both experiments, the bacteria added to live food or both live food and water induced higher growth rate at the highest dietary dose and this was associated with higher Ig levels on days 14 and 28. In experiment 2, higher survival was associated to lower type‐2 cannibalism (ingestion of whole prey) at the two dietary bacteria doses, and such positive effect was observed for fish fed bacteria at high density. Bacteria administration through water had no effect on growth and survival. In conclusion, the results show that high dietary concentrations of the mixture of bacteria used have potential stimulating impact on growth, survival, lysozyme activity and total Ig. But, further investigations are needed to demonstrate the optimal doses for emphasizing immune defence status.     

山杏林中杏仁蜂幼虫空间分布格局研究

通过5种聚集度指标和2种回归式,对山杏林中杏仁蜂幼虫空间分布格局进行研究分析,结果表明：在山杏林中,杏仁蜂幼虫空间分布格局为极具相互吸引的个体群形式的均匀分布。     

寄生沙棘木蠹蛾白僵菌及其微胶囊剂对不同昆虫的毒力

室内采用虫体喷菌法,测定了球孢白僵菌Beauveria bassiana SJ-05菌悬液及其微胶囊剂对不同昆虫幼虫的致病力。SJ-05菌悬液对枸杞负泥虫Lema decempunctata幼虫的LC50为3.45×107个/mL孢子;SJ-05菌悬液及其微胶囊剂对落叶松毛虫Dendrolimus superans幼虫的LC50分别为2.92×107个/mL和1.03×107个/mL孢子;对沙棘木蠹蛾Holcocerus hippophaecolus幼虫的LC50分别为9.79×106个/mL孢子和2.95×106个/mL孢子。菌株SJ-05对不同昆虫的致死中浓度不同,对沙棘木蠹蛾幼虫的致死中浓度低,致病力强。微胶囊比同浓度分生孢子悬液的致病力更强。