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31.
Claudia A. Bustos Mauricio F. Landaeta Enrique Bay-Schmith Rodrigo Lewis Ximena Moraga 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):535-540
Effects of exogenous (water temperature) and endogenous (lipid droplet adherence) factors were experimentally tested on early survival of southern hake Merluccius australis reared under controlled conditions. Experiments to determine the effect of temperature (10, 12 and 14 °C) on larval growth rates and yolk-sac absorption rates of unfed southern hake were carried out under laboratory conditions. There was no significant differences in growth rates at the temperature range tested (ANCOVA, F = 0.164, p > 0.25), but yolk-sac absorption rates and mortality increased with temperature (ANCOVA, F = 53.84, p < 0.001). A high percentage (between 31 and 81%) of hake eggs showed a lipid droplet not adhered (i.e., freely moving in the yolk, and not located in the posteriormost portion of the yolk-sac). In a second experiment, fed southern hake larvae with the lipid droplet not adhered during embryonic development did not survive after yolk-sac absorption. This study provides the first data on the influence of the lipid droplet absorption on larval survival of cultured hake, and can be used as an early indication of the quality of the batch. 相似文献
32.
栉孔扇贝秋季苗种培育、生长特性的初步研究 总被引:1,自引:0,他引:1
2004年9月20日~2005年5月9日,在红岛蛤原良种开发有限公司贝类育苗场进行了栉孔扇贝Chlamys farreri秋季苗种培育及其生长特性的研究。2004年11月中旬得到的壳高约0.1cm的秋季苗种2.2×106粒,在育苗池中暂养,12月份当水温降到8℃左右时移秋季苗种到保温效果比较好的藻类培育池中培养,苗种可安全过冬。次年5月当海区水温回升到10℃左右时将该苗种移到海上养殖区。2005年5~12月,通过对秋季苗种进行定点采样调查和生物学特性测定,结果表明,扇贝壳高的特定生长率SGR(%/d)在0.22±0.30~3.18±0.41之间,壳高与壳长的关系式为L=0.8101H-0.076,壳高、壳长与体重的关系式分别为W=0.1521H2.6268,W=03625L2.2191,成活率(%)在85±2.45~97.2±2.0之间。5~12月栉孔扇贝没有出现大量死亡现象,顺利地度过了夏季高温期。 相似文献
33.
为减少高密度养殖下菲牛蛭(Hirudinaria manillensis)疾病发生和养殖废水排放,研究比较了3种商品化有益微生物制剂(硝化细菌T1、光合细菌T2和EM复合菌T3)对养殖水体的净化效果。结果表明,3种有益微生物制剂在15d内均能使养殖水体的pH稳定在6.8以上,溶氧量(DO)分别比对照组提高30.12%、26.95%和46.12%;化学耗氧量(COD)分别比对照组低1.02mg/L、1.13mg/L和1.53mg/L;3个处理组对氨氮(NH4+-N)的平均降解率分别为48.48%、45.23%和63.10%,亚硝态氮(NO2-N)平均值分别比对照组低0.16mg/L、0.19mg/L和0.27mg/L;菲牛蛭存活率均高达90%以上,明显高于对照组的53%。3种有益微生物制剂均有显著增加溶氧量、降低氨氮、亚硝态氮和化学耗氧量的效应,对菲牛蛭养殖水体均具有很好的净化作用,其中以EM复合菌效果最佳。 相似文献
34.
35.
Danielle Johnston Roy Melville-Smith Blair Hendriks Bruce Phillips 《Aquaculture (Amsterdam, Netherlands)》2008,279(1-4):77-84
Wild caught post-pueruli, year one and year two post settlement juvenile western rock lobster, Panulirus cygnus, were held at ambient temperatures (15.6 °C to 23.1 °C; mean 19.0 ± 0.07 °C) or at 23 °C, and fed the same ration of a formulated pellet diet either once per night, or 3 times per night, over 12 months, to determine whether elevated temperatures and multiple feeds per night would stimulate growth through increased metabolism and feed utilisation without significant negative impacts on survival. Survival of post-pueruli (mean 63%) did not differ between ambient and 23 °C. Survival of year 1 and 2 juveniles was higher at ambient temperatures (p < 0.01 ambient: year 1 juveniles, 68%; year 2 juveniles, 88%; 23 °C: 57% and 74%, respectively). Feeding frequency did not affect survival of post-pueruli and year 2 juveniles (mean 63%, 81% respectively), but survival was 9% higher for year 1 juveniles fed three times per night (58% versus 67%; p < 0.01). All lobsters grew faster at 23 °C than at ambient temperatures (p < 0.05), with the growth of post-pueruli almost doubled at 23 °C (weight gain at 23 °C versus ambient: post-pueruli, 18 438 % versus 9 915 %; year 1 juveniles 259% versus 165%; year 2 juveniles 23% versus 21%). Feed frequency did not influence the growth of year 1 and 2 juveniles. However, there was an interaction effect of temperature and feed frequency on post-pueruli where weight and carapace length were significantly higher at ambient temperatures when post-pueruli were fed three times a day, whereas at 23 °C weight and carapace length were significantly greater when fed once per day (p < 0.05). Feed intake (g pellet dry matter lobster− 1 day− 1) of pellet was higher at 23 °C for all lobsters (p < 0.05), but was the same between lobsters fed 3 times per night versus once per night. This study has shown that increasing temperatures to 23 °C significantly improved the growth of P. cygnus post-pueruli without any adverse effects on survival. The faster growth rates exhibited by year 1 and 2 juveniles at 23 °C may potentially offset their lower survival by significantly reducing culture period. There is no benefit of feeding P. cygnus multiple times at night in terms of growth and survival. The implications for P. cygnus culture are that temperatures should be maintained close to 23 °C during the entire growout period, with due care taken to minimise mortalities through adequate provision of food and shelter. Feeding P. cygnus once daily to excess just prior to dusk to co-incide with nocturnal feeding behaviour is recommended. 相似文献
36.
Kenzo Yoseda Kazuhisa Yamamoto Kimio Asami Masayuki Chimura Koji Hashimoto Shinichi Kosaka 《Aquaculture (Amsterdam, Netherlands)》2008,279(1-4):55-62
This study investigated the effect of different light intensities on feeding, growth and survival of early stage leopard coral grouper Plectropomus leopardus larvae. Four different light intensities (0, 500, 1000 and 3000 lx) were used and larvae were kept under constant light conditions from 0 day after hatching (DAH) to 5 DAH. The larvae were fed a small S-type of Thai strain rotifers at a density of 20 individuals/mL from 2 DAH. The number of rotifers in larval digestive organ and total length of larvae were examined at 3 h intervals between 04:00 and 22:00 h on 3 DAH, and thereafter at 6 h intervals until the end of the experiment (5 DAH). Four experimental trials of the larval rearing were repeated using by 60 kL mass-scale rearing tanks. The results indicate that coral grouper larvae are visual feeders and their food intake increases with increasing light intensity. Food intake of larvae reared at 3000 lx was significantly higher than those reared at 0–1000 lx on 3 DAH despite being the first-feeding day (P < 0.01). On 4 DAH, total length of larvae reared at 3000 lx was significantly larger than those reared at the lower light intensities (0, 500 and 1000 lx), and thereafter light intensity significantly influenced larval feeding and growth until the end of the experiment. Survival on 5 DAH did not show a significant difference between light intensities, but survival rate at 3000 lx and 1000 lx had a tendency to be higher than those reared at the lower light intensities (0 and 500 lx). In contrast, larvae reared at 0 lx exhibited stagnant and/or negative growth. These results indicate that light intensity is significantly the factor affecting larval feeding, growth, and survival in coral grouper larvae under the rearing conditions. 相似文献
37.
An experiment was conducted to evaluate the rearing performance of different larval stages for optimum growth and survival during fingerling production of Clarias batrachus with an aim to reduce the rearing time of the catfish larvae in a hatchery system. The larvae were reared for 5, 10 and 15 days before stocking them in the nursery tanks. No significant (P < 0.05) difference could be found in length increment at the end of first week of rearing. But the total length was reduced during rest three weeks in five days old larvae compared to that of other two higher age groups. In 5 days old larvae the reduced weight (P < 0.05) was observed during the entire rearing period. However, the specific growth rate (SGR) did not vary among the groups. The survival rate as well as total biomass was decreased while stocking five days old larvae for rearing, compared to that of other two age groups. 相似文献
38.
Yoshimasa Sugiura Kohji Matsuda Takashi Okamoto Makoto Kakinuma Hideomi Amano 《Fisheries Science》2008,74(1):180-186
To investigate the anti-allergic effects of the brown alga Eisenia arborea. A strain of Brown Norway rats know to strongly respond to immunoglobulin E (IgE) were used as an allergy model animal. The
rats were immunized with ovalbumin by oral administration. The levels of serum IgE and histamine were suppressed in the rats
fed a diet supplemented with dried E. arborea powder. As for the cytokine pattern, the interferon-γ production in the spleens and mesenteric lymph nodes (MLN) was enhanced,
and the interleukin-4 (IL-4) production in the spleens and/or IL-10 production in the spleens and MLN were suppressed. These
results, together with the change in the Th1/Th2 balance, indicate that the rats fed with E. arborea became more anti-allergic, suggesting that E. arborea might possess anti-allergic effects. 相似文献
39.
40.
In order to change for the good flavor in green tea of middle or low grade,roast naked barley (miner ingredient) was added to it.To make tea having functional property,mixed roast naked barley-green tea with one medicinal herb (MH,miner ingredient).This study was performed to investigate the effect of drinking extracts of naked barley-MH-green tea (A group) and adlay-Angelica gigas Nakai-green tea (B group) on the body weights of rats,and volatile flavor components of best effective extract on weight reduction.Forty-eight male Sprague-Dawley rats divided into six groups were fed five different green tea extracts for 8 weeks.The result obtained in the experiment indicated that the change of body weights of rats was affected by A group,B group and others.A group showed highest reduction rate of body weights (36.40%).Reduction rate of body weights on the B group (10.10%) was much lower than A group (36.40%).Aroma compounds were extracted by the SDE method.The concentrated aroma extracts were analyzed and identified by GC and GC-MS.The main aroma components of the green tea blended with naked barley and MH were 12 pyrazines having roasty note,methyl butanals having sweet note,hexanal having briskness greenish note,and nerolidol and3-ionone having floral note. 相似文献