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961.
Effect of supplemental dietary slow‐release urea on growth performance and physiological status of dairy heifers 下载免费PDF全文
Jiaojiao Zhang Qiang Qiu Zhanhuan Shang Shujie Liu Allan Degen Shanshan Li Qi Yan Weiwei Wang Xiaoping Jing Yanfu Bai Luming Ding 《Animal Science Journal》2018,89(7):966-971
We examined the effect of supplemental dietary slow‐release urea on the growth performance and physiological status of 16 dairy Holstein heifers (10 months of age, 322 ± 10 kg). The heifers were offered a formulated isocaloric and isonitrogenous 70:30 roughage : concentrate ration and were assigned randomly to one of four levels of slow‐release urea supplementation (0% [U0], 1% [U1], 1.5% [U1.5] and 2% [U2] dry matter [DM]). The total study lasted 95 days, which included a 20 days adaptation period. Dry matter intake (DMI) of U2 was lower than the intakes of U0 and U1 (p < .05), while average daily gains (ADG) of U1 and U1.5 were higher than U0 and U2 (p < .05). Rumen volatile fatty acids concentration did not differ among the four treatments, while ammonia nitrogen concentration increased with an increase in urea level (p < .05). Serum blood urea nitrogen concentration was lower in U1.5 than in U0 and U2 while serum free fatty acids concentration in U2 was higher than in the other three treatments (p < .05). We concluded that the addition of urea at a level of 1.5 to 2.0% DM resulted in a reduction in DMI but the addition of 1.0%–1.5% urea resulted in the highest ADG, with no negative effects on rumen fermentation and health status of the calves. 相似文献
962.
Wenjun Wang Yi Nie Yanrong Liu Lu Bai Jinsen Gao Suojiang Zhang 《Fibers and Polymers》2017,18(9):1780-1789
Cellulose/multi-walled carbon nanotubes (MWCNTs)- composite membranes applied in electrochemical and biomedical fields were prepared using 1-ethyl-3-methylimidazolium diethyl phosphate (EmimDEP) as solvent in this study. With the increasing of MWCNTs amount, the membrane conductivity increased, and the conductivity reached 9.1 S/cm as the mass ratio of MWCNTs to cellulose being 2:1. The additions of sodium dodecyl sulfate (SDS), 1-hexadecyl-3-methylimidazolium bromide (C16mimBr) and 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF4) efficiently improved the conductivity, mechanical property, and thermal stability by promoting the dispersion of MWCNTs. When the mass ratio of C16mimBr to MWCNTs changed from 0 to 0.3:1, the conductivity increased from 0.08 S/cm to 0.14 S/cm, and the tensile strength increased from 13.3 MPa to 17.0 MPa. These results indicate that the binary ionic liquids (ILs) system can regulate the properties of the composite membranes, and is a feasible approach for preparing cellulose/MWCNTs composite membranes with enhanced properties. 相似文献
963.
为了解决花生收获过程中的实时自动测产及远程数据监测存储问题,设计了基于智能传感器的花生收割机实时测产远程监测存储系统,提出了一种新的测产机械结构和方法,并利用智能路由器加密通道建立了一套API框架体系,实现了测量数据的远程传输与实时共享。试验结果表明:收割机终端测产值与智能路由器传回至服务器的数据相对误差绝对值小于5%,数据传输速度快,具备较大的扩展性,验证了测产系统的可行性、可靠性和准确性,应用前景宽广。 相似文献
964.
在0、12、36、60 h不同时间梯度下,对7个燕麦(Avena sativa)品种(青引1号、青引2号、青引3号莜麦、青海甜燕麦、青海444、青燕1号和林纳)进行连续低温(5℃)胁迫,比较其抗寒能力。结果表明,与低温胁迫前(0 h)相比,低温处理后(12、36和60 h)7个燕麦品种幼苗叶片丙二醛、脯氨酸含量和超氧化物歧化酶、过氧化物酶活性均显著增加(P0.05);各燕麦品种幼苗叶片丙二醛、脯氨酸含量和过氧化物酶、超氧化物歧化酶活性在低温胁迫初期(0-12 h)显著增加(P0.05)并达到最大值;随着低温胁迫时间延长,其含量开始下降。7个燕麦品种抗寒能力依次表现为青引3号莜麦青海甜燕麦青引2号林纳青燕1号青海444青引1号。 相似文献
965.
Optimum Dietary Protein Level and Protein‐to‐energy Ratio for Growth of Juvenile Parrot Fish,Oplegnathus fasciatus 下载免费PDF全文
Kang‐Woong Kim Kyoung‐Duck Kim Hyon Sob Han Mohammad Moniruzzaman Hyeonho Yun Seunghan Lee Sungchul C. Bai 《Journal of the World Aquaculture Society》2017,48(3):467-477
An 8‐wk feeding trial was conducted to estimate the optimum dietary protein level and protein‐to‐energy (P/E) ratio in juvenile parrot fish, Oplegnathus fasciatus. Eight experimental diets were formulated with two energy levels and four protein levels for each energy level. Diets containing crude protein (CP) at 35, 40, 45, and 50% had either 12.5 or 14.6 kJ/g of energy. Fish averaging 7.1 ± 0.06 g (mean ± SD) were fed one of the experimental diets for 8 wk. At the end of the feeding trial, weight gain (WG) of fish fed 45 and 50% CP in the 12.5 kJ/g diet was significantly higher than fish fed the 35% CP diet (P < 0.05). WG of the fish fed 45 and 50% CP in the 14.6 kJ/g diet was significantly higher than fish fed the 35 and 40% CP diets (P < 0.05). Fish fed the 14.6 kJ/g diet had a higher WG compared with fish fed the 12.5 kJ/g diet at all CP levels. Feed efficiency (FE) and specific growth rate (SGR) showed a similar trend to the WG. WG, FE, and SGR improved with increasing dietary protein levels up to 45% and remained constant at 50% CP for both energy levels. However, protein efficiency ratio was negatively related to dietary protein levels. The results suggested that the optimum level of protein and the optimum P/E ratio for juvenile parrot fish should be 45% and 31.1 mg protein/kJ, respectively, in a diet containing 14.6 kJ/g energy. 相似文献
966.
光照对月季‘光谱’花青素合成及其CHS和DFR基因表达的影响 总被引:1,自引:0,他引:1
探明变色月季花开放过程中花色变化的相关调控机制,可以为月季花色育种提供理论依据。本研究测定了月季‘光谱’在正常光照和遮光条件下的总花青素含量及月季‘光谱’花冠中CHS、DFR基因在两种条件下的差异表达,试图同时从代谢水平以及分子水平上进行探讨变色月季‘光谱’的变色机理。研究结果表明:光照是影响‘光谱’变色的关键环境因素,遮光阻碍了‘光谱’花瓣中花青素的合成,抑制了基因CHS和DFR的表达,导致花冠不着色,证明了花青素是决定月季的花冠由黄色变为红色的主要物质,也证明了基因CHS和DFR在花青素合成过程中的重要作用。 相似文献
967.
968.
969.
分析了黑龙江省森工林区伐区调查设计及作业质量存在的问题和原因,有针对性地提出了解决对策。 相似文献
970.
Bioassay method was used to study the biological activity of different polar solvent extracts of False ragweed seed. Specially, water extracts of False ragweed has an effect on plant germination and root length. The study found that False ragweed seed extracts had different degrees of inhibition on many plant seed germinations, and inhibited the germination of cucumber seeds best, the maximum inhibition rate was 79.5%, for cabbage, sorghum and maize seed germination inhibition rate was more than 30%. False ragweed seed extracts also had strong inhibition on cucumber and many other plant root length, and inhibited the root length of cucumber best followed by red beans. The result showed that False ragweed seed extracts contained some materials that could inhibit germination and growth of some plants. 相似文献