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几种植物浆养殖卤虫的饵料效果 总被引:11,自引:0,他引:11
以各种植物浆为饵料培养卤虫,培养效果差异显著,陆生植物优于水生植物.其中以黄豆叶浆养殖的卤虫成活和生长最佳,第16天时平均存活率(69.6%)和体长(6.436±0.956mm)与螺旋藻粉组相似(分别为66.0%、6.461±1.181mm)而优于酵母组(分别为29.8%、5.216±1.030mm).以黄豆叶浆养殖的卤虫的粗蛋白及氨基酸含量略低于酵母和螺旋藻粉喂养的卤虫,在高密度卤虫养殖中可替代部分螺旋藻粉,降低卤虫养殖的饵料成本. 相似文献
95.
The experiment investigated whether the effect of enzyme supplementation on performance and nutrient digestibility is dependent on type of the ingredient(s) used, by incorporating wheat bran (WB), sunflower meal (SFM) and citrus pulp (CP) to a reference diet (REF). Those ingredients are known to be rich in different types of non‐starch polysaccharides (NSP). Diets were supplemented with and without (control) an enzyme mix (phytase 1,000 FTU/kg and xylanase U/kg) according to a 2 × 4 factorial arrangement. In total, 24 tanks (3 replicates/treatment) were used with 30 fish each (Nile tilapia, Oreochromis niloticus; mean initial body weight 41 g). Fish were restrictively fed the experimental diets for 43 days (80% of expected satiation). Enzyme supplementation affected the absolute growth (g/day) and FCR (p < 0.05), improving the growth of fish fed the WB and SFM diets, while fish fed the REF and CP diets did not benefit. NSP, energy, ash, phosphorous and calcium digestibility improved with enzyme supplementation (p < 0.05). There was an interaction effect on all growth parameters, as well as the digestibility of energy and phosphorus (p < 0.05). This indicates that the effectiveness of the enzymes was dependent on the NSP‐rich ingredient used and thus the composition of the NSP fraction. 相似文献
96.
为分析电子捕捞日志数据的准确性和可信度,以“粤新会渔01282” “粤新会渔01240” “粤新会渔01286” “粤新会渔01239” “粤茂滨渔47239” “粤新会渔02163” “粤茂滨渔42278” “粤新会渔00070”和“粤新会渔01268”9艘拖网渔船2018年8月17日—2019年4月30日的作业状态为研究对象,利用北斗船位数据提取拖网作业时间、作业网次和作业渔区,与电子捕捞日志数据的相关信息进行比较验证。结果表明,9艘拖网渔船的电子捕捞日志数据与北斗数据提取的作业时间的重复率分别为36.7%、64.8%、71.4%、81.5%、24.7%、46.7%、66.7%、79.6%和68.9%。作业渔区的重复率分别为80%、86.9%、65.7%、74.7%、75.3%、85.6%、71.6%、56.9%和65.2%,作业网次的重复率分别为65%、86.4%、60%、70%、75.3%、67.1%、54.4%、62.1%和35.4%。作业时间与渔获量的相关性分析结果表明,“粤新会渔01286” “粤新会渔01239” “粤新会渔01240”和“粤茂滨渔47239”的作业时间与渔获量呈极显著相关(P<0.01),“粤茂滨渔42278”的作业时间与渔获量呈显著相关(P<0.05),“粤新会渔01282” “粤新会渔02163” “粤新会渔00070”和“粤新会渔01268”的作业时间与渔获量无显著相关性(P<0.05),反映出电子捕捞日志数据的准确性和可信性尚有空间可待提高。
相似文献97.
杨树纸浆林造林模式的研究 总被引:1,自引:0,他引:1
为优化杨树小径材纸浆林模式,采用多分子的正交试验方法,通过对试验数据的统计分析和比较,筛选出较理想的纸浆林模式为:①立地条件中上等:A2B1C2———美洲黑杨·1666株/hm2·1m×6m·集约经营·6年主伐;A3B1C2———欧美杨·1666株/hm2·1m×6m·集约经营·6年主伐。②立地条件稍差:A2B2C2———美洲黑杨·1111株/hm2·1.5m×6m·集约经营·7年主伐;A3B2C2———欧美杨·1111株/hm2·1.5m×6m·集约经营·7年主伐。 相似文献
98.
The use of decay-class systems in characterising the state of decomposition of a forest’s complement of rotting logs is widespread. While most systems are based on an assessment of logs’ external characteristics, there is an implicit assumption that doing so captures important information on the underlying processes of internal decomposition. However, the validity of this remains largely untested. We explored the relationship between decay-class and internal state of decomposition in logs of Eucalyptus obliqua in the lowland wet eucalypt forests of Southern Tasmania, Australia. We examined rotten-wood samples from a large population of logs across a wide range of diameters. From this we determined that smaller-diameter (<60 cm: regrowth-sized) logs differ from larger-diameter (>60 cm: mature-sized) logs in their pathways of internal decomposition. Decomposition in regrowth-sized logs is characterised by greater activity of surface rots, with white rot-types predominating. Decomposition in mature-sized logs is more concentrated in the interior of the log, with brown rot-types tending to dominate. These differences probably both reflect and help shape the communities of organisms inhabiting logs of different origins. Despite these differences, regrowth and mature-sized logs show the same general progression of internal decomposition across the five decay-classes, to the extent that each class represents logs that have lost a predictable proportion of their original mass. We conclude that a decay-class system that is restricted to a single dimension, such as the five-class system used for E. obliqua, will be quite able to capture the main trajectory of biomass loss, but will not be able to characterise the complexity of the ecological processes giving rise to this loss. Studies that employ single-dimension decay classes, and which aggregate decay-class data across logs, can be given added ecological meaning by first partitioning logs into diameter-classes that reflect the underlying differences in the maturity of the trees giving rise to the logs. For E. obliqua logs, a cut-off diameter of 60 cm offers an appropriate distinction between regrowth-aged and mature-aged trees. 相似文献
99.
以森林经营模式理论为指导,依据湿地松纸浆材原料林经营模式的经营模拟系统,建立了该经营模式的经营技术体系.研究结果表明:按照该经营模式提供的优化经营技术,经营湿地松纸浆材原料林,可获得最佳的经营效果,投入产出比高达494% 相似文献
100.
硫酸盐草浆黑液制粉状活性炭的研究 总被引:2,自引:0,他引:2
本文探讨硫酸盐草浆纸厂黑液的治理和利用,提出用酸化法从黑液中沉析木素制取粉状活性炭。大约生产10t草浆可制取1t优质粉状活性炭。同时还含有占总碱量24%的Na_2S可回收。排出的废液即使不再经过处理,其污染程度也已大大降低。 相似文献