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91.
92.
The potential of three different protein resources (pea protein isolate, PPI; pea protein concentrate, PPC; enzyme treated poultry protein, ETPP) as fish meal (FM) alternative protein in diets for juvenile black sea bream, Acanthopagrus schlegelii. (initial average weight 7.90 ± 0.13 g) was evaluated. Seven isonitrogenous and isoenergetic diets were formulated to replace FM at 0% (T0, control diet), 8% (designated as T1‐T3) and 16% (designated as T4‐T6) using PPI, PPC and ETPP respectively. Each diet was randomly assigned to triplicate groups of 25 juvenile fish for 8 weeks. At the end of the feeding period, survival rate was not significantly affected by dietary treatments. Growth performance in T6 (16% ETPP) group was significantly inferior to T0 group, however, weight gain and specific growth rate in other treatments showed no significant differences (P > 0.05). Mean feed intake, feed efficiency ratio and protein efficiency ratio were also poorer in fish fed in T6 than those of fish fed with the control diet respectively. Apparent digestibility coefficients (ADCs) of dry matter and crude protein for fish fed ETPP diets were significant lower than those of fish fed with the control diet, whereas ADCs of lipid were unaffected by dietary treatments. ADC's of dietary Leu, Ile, His and Lys was also significantly influenced. There were no marked variations in proximate compositions of dorsal muscle. With regard to plasma characteristics, significant difference was observed in triacylglycerol content. Ammonia concentration in plasma tended to increase in alternative protein diets as substitution level increased. There were significant differences in aspartate aminotransferase activities among groups, but alanine aminotransferase levels were unaffected by treatments. In conclusion, the present study demonstrated that PPI and PPC were potential protein sources for using in juvenile black sea bream diet. However, the substitution level of FM by ETPP should be limited within 16%. 相似文献
93.
94.
根系分区交替滴灌条件下葡萄根系分布特征及生长动态 总被引:7,自引:0,他引:7
采用原位取土法和根系生态监测系统连续两年研究了葡萄的根系空间分布和全生育期根系生长动态,结果表明:葡萄根系在水平方向主要分布在距离树干100 cm的范围内,占到总根系的80%以上,而且在径向方向呈指数衰减;葡萄根系在垂直方向主要分布在0~60 cm范围的土层内,占到总根系的75%以上.根系分区交替滴灌条件下干燥区与湿润区根系生长是不同的,葡萄的新生根系受到土壤水分条件的限制和自身生长的影响.在整个生育期,葡萄根系分区交替滴灌两侧根系生长均呈抛物线变化. 相似文献
95.
设计了用于洁蛋保鲜高效自动涂膜的洁蛋覆膜机,开发了控制系统,通过试验对设备的性能进行了验证.对电动机频率分别为5、10、15、20、25、30 Hz下的进蛋链条线速度和设备的处理量进行性能测试,验证了装置的实际生产能力.蛋壳表面干燥情况与覆膜状况的试验结果表明,在温度为25℃,相对湿度为60%,喷雾压力为0.6 MPa,单位时间喷雾量为43.6 mL/min,烘干机干燥能力为1.71 kJ/s时,最佳进蛋链条线速度为12.01 mm/s,处理量为4804颗/h,烘干机长度为50 cm,洁蛋干燥时间为4.16s. 相似文献
96.
蝗虫对蓝光偏振光和非偏振光的定向响应对比 总被引:2,自引:0,他引:2
为给蝗虫灾害光电诱导捕集治理技术中蝗虫诱导光场性质的确定及不同光场的筛选组合提供理论支持,利用LED光谱色非偏振光、蓝光偏振光和行为反应试验装置,进行了不同光照特性的蓝光偏振光场和光谱色非偏振光场对蝗虫定向选择的对比试验,探讨了不同光场对蝗虫定向选择行为影响的机理.结果表明:蓝光偏振光条件下,蝗虫对光谱色非偏振光的趋光定向响应以紫光最优;蝗虫对偏振光和紫光的趋光定向响应对比中,蝗虫对线偏振光和紫光选择的对比率差别最小;蝗虫对偏振光的趋光定向响应取决于偏振光的光照强度,对非偏振光的趋光定向响应取决于光谱色和光照强度;蝗虫敏感光谱色光照强度和蓝光偏振光光照强度对蝗虫趋光响应敏感临界点的差别程度是影响其趋光定向响应选择差异的原因,但就光场光照性质而言,蝗虫敏感光谱色及其光照强度是提高蝗虫诱导率的关键因素. 相似文献
97.
98.
Purpose
Cover crop residue is generally applied to improve soil quality and crop productivity. Improved understanding of dynamics of soil extractable organic carbon (EOC) and nitrogen (EON) under cover crops is useful for developing effective agronomic management and nitrogen (N) fertilization strategies.Materials and methods
Dynamics of soil extractable inorganic and organic carbon (C) and N pools were investigated under six cover crop treatments, which included two legume crops (capello woolly pod vetch and field pea), three non-legume crops (wheat, Saia oat and Indian mustard), and a nil-crop control (CK) in southeastern Australia. Cover crops at anthesis were crimp-rolled onto the soil surface in October 2009. Soil and crop residue samples were taken over the periods October?CDecember (2009) and March?CMay (2010), respectively, to examine remaining crop residue biomass, soil NH4 +?N and NO3 ??CN as well as EOC and EON concentrations using extraction methods of 2?M KCl and hot water. Additionally, soil net N mineralization rates were measured for soil samples collected in May 2010.Results and discussion
The CK treatment had the highest soil inorganic N (NH4 +?N?+?NO3 ??CN) at the sampling time in December 2009 but decreased greatly with sampling time. The cover crop treatments had greater soil EOC and EON concentrations than the CK treatment. However, no significant differences in soil NH4 +?N, NO3 ??CN, EOC, EON, and ratios of EOC to EON were found between the legume and non-legume cover crop treatments across the sampling times, which were supported by the similar results of soil net N mineralization rates among the treatments. Stepwise multiple regression analyses indicated that soil EOC in the hot water extracts was mainly affected by soil total C (R 2?=?0.654, P?<?0.001), while the crop residue biomass determined soil EON in the hot water extracts (R 2?=?0.591, P?<?0.001).Conclusions
The cover crop treatments had lower loss of soil inorganic N compared with the CK treatment across the sampling times. The legume and non-legume cover crop treatments did not significantly differ in soil EOC and EON pools across the sampling times. In addition, the decomposition of cover crop residues had more influence on soil EON than the decomposition of soil organic matter (SOM), which indicated less N fertilization under cover crop residues. On the other hand, the decomposition of SOM exerted more influence on soil EOC across the sampling times among the treatments, implying different C and N cycling under cover crops. 相似文献99.
100.
长江流域滩地是我国钉螺分布的主要区域,也是血吸虫病的主要流行区。近些年我国大力实施的林业血防工程通过滩地营造人工杨树林,使得钉螺原有孳生地的多种生物要素和非生物要素发生了明显变化,显著减少了钉螺种群的分布空间,从而有效控制了血吸虫病的传播。目前,国内外在滩地造林后单一要素改变对钉螺的影响方面已有较多研究,但有关生物要素与非生物要素对钉螺分布的交互作用还未有深入探索,对钉螺孳生产生抑制作用的关键要素尚不明确。文中综述了滩地造林后林下的草本植物群落、土壤理化性质、光照、地温等诸多要素发生变化对钉螺生存的不利影响,总结了滩地造林抑螺作用机理的研究进展,提出该领域今后的重点研究方向,以期为滩地造林抑螺作用机理的深入研究提供参考和借鉴。 相似文献