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841.
烟青虫生物学特性观察 总被引:4,自引:0,他引:4
1996~1997年在云南省红河烟区弥勒县的烤烟大田设置尼龙纱网养虫室,自然条件下连续饲养烟青虫Heliothis assulta(Guene),系统观察各虫态历期、幼虫龄期、取食量及体色变化,幼虫化蛹龄期及成虫羽化、产卵等.结果表明,烟青虫1年发生4~5代,各代均有5龄和6龄幼虫化蛹,5龄幼虫化蛹占60%以上;1龄幼虫历期比2龄历期长,3龄以后龄期增长,末龄(5龄或6龄)幼虫龄期最长;5龄化蛹的幼虫平均历期比6龄化蛹的短;无论5龄或6龄化蛹,3龄以后食量剧增,5~6龄的取食量为1~4龄取食量的1倍以上;幼虫体色多变,1龄幼虫均为红褐色,2~6龄体色变化无规律可循,第2代以后体色有随世代增加而加深的趋向;成虫产卵量与补充营养关系密切,补充营养充足时,每雌可产卵600~900粒,一般情况产400~500粒,未交配雌虫也会产卵,但卵不能孵化.根据观察结果提出了防治中应注意的问题. 相似文献
842.
Dora Zouiten Ines Ben Khemis Raouf Besbes Chantal Cahu 《Aquaculture (Amsterdam, Netherlands)》2008,279(1-4):166-172
This work describes the ontogeny of the digestive tract in thick lipped grey mullet (Chelon labrosus) larvae reared until day 36 post-hatching with the semi-extensive technology in mesocosms. Diet was constituted by live preys, rotifers, Artemia and wild zooplankton, then compound diet was added from day 20 (p. h.). Linear growth, weight growth and digestive enzymes specific activities were studied during larval ontogeny. Pancreatic enzymes (trypsin and amylase) and intestinal enzymes (leucine-alanine peptidase “Leu-ala”, aminopeptidase N “AN” and alkaline phosphatase “AP”) were assayed in larvae sampled throughout the rearing trial to evaluate gastrointestinal maturation along the development.The trypsin specific activities were very high during the first two weeks and then declined as observed in marine fish species. A following increase in trypsin specific activity from day 20 was attributed notably to ingestion of particle compound diet. In contrast to the pattern generally described in fish larvae, amylase specific activity showed a continuous increase. This could be attributed to the fact that C. labrosus is an omnivorous species and suggests that the fish might be able to use efficiently diets containing higher levels of starch or other carbohydrates since the end of larval development.Relative expression of intestinal brush border membrane enzymes (AP and AN) and cytosolic enzyme (Leu-ala), showed an abrupt increase of both AP/leu-ala and AN/leu-ala ratios at day 8 (p. h.), indicating that maturation of intestinal tract in C. labrosus larvae is particularly precocious. It is assumed that larvae of C. labrosus might support early co-feeding and weaning strategies, which could reasonably be initiated since mouth opening. 相似文献
843.
Takuma Sugaya Michihiro Sato Emi Yokoyama Yuta Nemoto Tomonari Fujita Hiroyuki Okouchi Katsuyuki Hamasaki Shuichi Kitada 《Fisheries Science》2008,74(3):579-588
ABSTRACT: The genetic diversity of wild and hatchery-released Pacific herring Clupea pallasii collected from three brackish lakes and two bays in Honshu and Hokkaido, Japan was examined with five microsatellite loci. All loci showed high genetic variability with expected heterozygosities ranging from 0.815 to 0.945. Significant differences in genotypic and allelic distributions were detected among all locations except for between the two bays in Honshu Island. Pairwise population analysis based on the F ST values showed close genetic relationships among the locations in Hokkaido Island, and the hierarchical analyses of molecular variance showed significant genetic difference between the two islands. Those results suggest the existence of subpopulations due to natal homing. In addition, stocked fish showed as much genetic diversity as the wild fish. The pairwise population analyses also showed close relationships between the hatchery fish and the wild fish in respective stocking areas, showing that no effects of stocking programs on genetic diversity of wild populations were detected. 相似文献
844.
Abstract Temporal patterns in length frequency distributions and hatch dates were described for larval yellow perch, Perca flavescens (Mitchill), captured in surface ichthyoplankton trawls from late April to mid-June 2000 to 2002 in six South Dakota, USA lakes. Fewer than 15 larval yellow perch were collected in four of six lakes during 2002, suggesting that in some cases factors prior to, during or immediately after hatching likely play a critical role in the perch recruitment process. When larval yellow perch were encountered in larger numbers, temporal trends in total length (TL) frequencies indicated that only a single cohort was produced annually in each lake. Most yellow perch in these lakes hatched between 29 April and 17 May, and most hatching occurred during 5–11 days each year. Larval TL was not related to hatch date. The apparent prevalence of relatively short hatch periods in these yellow perch populations probably increases the risk of catastrophic losses resulting from periods of poor environmental conditions. 相似文献
845.
846.
近年来海洋仔鱼消化系统,包括胃、肠道以及胰脏发育的研究进展进行了综述,描述了其消化系统在发育过程中形态和功能的变化,对仔鱼发育过程中包括胃蛋白酶、胰酶、肠酶及其他消化酶的变化以及饵料组分的影响进行了总结。 相似文献
847.
848.
Laura Ribeiro Ana Couto Mercedes Olmedo Blanca Álvarez-Blázquez Fátima Linares & Luísa M P Valente 《Aquaculture Research》2008,39(4):339-346
Blackspot seabream, Pagellus bogaraveo (Brunnich), has been identified as a potential species to diversify European aquaculture production. Although rearing aspects have been widely investigated, little information exists on the nutritional requirements for this species. The aim of this study was to build up information on the activity of digestive enzymes at certain developmental stages of blackspot seabream in order to understand the nutritional needs of larvae and post larvae. Fish larvae were reared from hatching to 55 days after hatching (dah), and the feeding plan consisted in rotifers (5–35 dah), Artemia naupli (30–35 dah) metanaupli (35–45) and Gemma microdiet (45–55 dah). At 7, 11, 21, 45 and 55 days after hatching (dah), pooled samples of fish larvae were collected for analysis of trypsin, amylase, lipase, alkaline phosphatase and leucine–alanine peptidase activity. Up to 21 dah, the whole larvae body was used for enzymatic analysis, whereas in older larvae only the dissected abdominal cavity was used. Blackspot seabream body dry weight growth was exponential, increasing from 60 μg at 5 dah to 30±9.7 mg at 55 dah. Amylase specific activity decreased significantly during development, exhibiting at 11 dah (0.6 U mg?1 protein) an average value 2.7 times lower than at 7 dah, and remaining stable between 45 and 55 dah (0.7 U mg protein?1). Trypsin specific activity remained constant until 21 dah (between 38 and 44 mU mg protein?1), which could be related to the larvae feeding regime. At later stages of development, lipase‐specific activity exhibited a significant increase (P<0.05), being three times higher at 55 dah (8 U mg protein?1) than at 45 dah. The total activity of the studied digestive enzymes increased significantly during larval development (until 21 dah), whereas afterwards only lipase and leucine–alanine peptidase increased significantly between 45 and 55 dah. The pattern of digestive enzymes activity was related to organogenesis and the type of food used at different developmental stages. 相似文献
849.
Elisabeth Criscuolo Urbinati Lúcia Helena Vasques José Augusto Senhorini Valéria Leão Souza Flávio Daolio Gonçalves 《Aquaculture Research》2008,39(13):1355-1359
This study compared the larval performance of matrinxã, Brycon amazonicus, after maternal triiodothyronine (T3) injection or egg immersion of T3. In the first experiment, three groups of females (n=4) induced to spawning received pituitary extract (CPE) and a corn oil injection (control), or CPE plus 10 mg or 20 mg kg?1 bw T3 dissolved in corn oil (experimental). Larvae were sampled for body weight and length measurement at hatching (0 h) and 12, 24, 36, 48 and 60 h thereafter. Hatching time, hatching success and abnormal development were monitored. In the second experiment, fertilized eggs from four females were immersed in T3 solutions (0, 0.01, 0.05 and 0.10 mg L?1) and larvae were sampled at hatching (0 h) and 6, 18, 30, 42, 54, 126 and 198 h thereafter. Hatching time was not affected by either means of hormone treatment. Abnormalities decreased as the T3 concentration increased in larvae from T3‐treated broodfish but the number of dead larvae increased proportionally. Larvae from T3‐injected females had higher weight from 24 h after hatching and greater length from hatching, while the weight of larvae produced from T3‐immersed eggs changed at 198 h and length from 126 h of rearing. Both routes of T3 administration affected the early growth of matrinxã but the effect was observed earlier when broodstock females were injected. 相似文献
850.