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91.
本试验旨在研究凝结芽孢杆菌对热应激肉鸡生长性能及肠道消化与吸收功能的影响。选择320只28日龄健康爱拔益加(AA)肉公鸡,随机分为5个组,每组8个重复,每个重复8只。常温对照组(TC组)肉鸡饲养于(22±1)℃的常温环境,饲喂基础饲粮;热应激组(HS组)肉鸡饲养于(34±1)℃的高温环境,饲喂基础饲粮;热应激试验组肉鸡饲养于(34±1)℃的高温环境,分别饲喂在基础饲粮中添加0.2×107(HS-BC0.2组)、1.0×107(HS-BC1.0组)、5.0×107CFU/g(HS-BC5.0组)凝结芽孢杆菌的试验饲粮。试验期14 d。结果表明:与TC组相比,HS组的末重、平均日增重(ADG)、平均日采食量(ADFI),干物质和粗蛋白质表观代谢率,空肠食糜总淀粉酶和总蛋白酶酶活,空肠绒毛高度、绒毛高度/隐窝深度以及空肠钠/葡萄糖协同转运蛋白1(SGLT1)、基础氨基酸转运载体(r-BAT)、y+L氨基酸转运载体-1(y+LAT1) mRNA表达量均显著降低(P<0.05),料重比(F/G)显著增加(P<0.05)。与HS组相比,HS-BC1.0和HS-BC5.0组的ADG、粗蛋... 相似文献
92.
A modern computer-based simulation tool (WaterMan) in the form of a game for on-farm water management was developed for application in training events for farmers, students, and irrigators. The WaterMan game utilizes an interactive framework, thereby allowing the user to develop scenarios and test alternatives in a convenient, risk-free environment. It includes a comprehensive soil water and salt balance calculation algorithm. It also employs heuristic capabilities for modeling all of the important aspects of on-farm water management, and to provide quantitative performance evaluations and practical water management advice to the trainees. Random events (both favorable and unfavorable) and different strategic decisions are included in the game for more realism and to provide an appropriate level of challenge according to player performance. Thus, the ability to anticipate the player skill level, and to reply with random events appropriate to the anticipated level, is provided by the heuristic capabilities used in the software. These heuristic features were developed based on a combination of two artificial intelligence approaches: (1) a pattern recognition approach and (2) reinforcement learning based on a Markov decision processes approach, specifically the Q-learning method. These two approaches were combined in a new way to account for the difference in the effect of actions taken by the player and action taken by the system in the game world. The reward function for the Q-learning method was modified to reflect the suggested classification of the WaterMan game as what is referred to as a partially competitive and partially cooperative game. 相似文献
93.
Several field studies were conducted tobetter understand the influence of culturalpractices, inflow rate and field conditionson the performance of modern surfaceirrigation systems in Egypt. Field datawere collected on wheat and cotton underEgyptian conditions in order to estimateinfiltration, roughness and performanceparameters. Tests were made with a varietyof inflow rates and a variety ofcross-section shapes (flat or furrowed andseveral furrow spacings). These studiesprovide information on expected values ofinfiltration and roughness parameterstypical of cracking clay soils in the NileDelta, as well as guidelines andrecommendations for use of long-levelbasins in Egypt. 相似文献
94.
The impacts of blanket peatland management on water tables, near‐surface macropore flow and saturated hydraulic conductivity were investigated using automated dipwells and mini‐disc tension infiltrometers. Three neighbouring hillslopes which were undisturbed, drained and restored by drain blocking were studied. Mean water table depths at the undisturbed sites were slightly shallower than at the restored site and water tables at both sites were significantly shallower relative to the drained treatment. Through time, however, the water table at the restored treatment behaved in a markedly different way to that at the undisturbed site. Water tables reached the peat surface for only 2% of the time for the drained and restored treatments compared to 18% for the undisturbed treatment. The proportion of runoff flowing through macropores in the near‐surface layers of the peat was found to be large (≥60%) across all three treatments, yet functional macroporosity was found to be significantly greater in the undisturbed peat relative to the two other treatments. Meanwhile, saturated hydraulic conductivity was found to be significantly higher at the restored treatment relative to the two other treatments, with mean conductivities ca. 1.5 times greater, suggesting a form of heightened soil–water interaction. Combined, the results indicate that although restoration by ditch blocking may result in a relatively successful water table recovery, there may not be the full reinstatement of peatland hydrological processes. 相似文献
95.
An 8‐week feeding experiment was conducted to determine the effect of dietary betaine levels on the growth performance and hepatic intermediary metabolism of genetically improved farmed tilapia (GIFT) strain of Nile tilapia Oreochromis niloticus (mean initial body weight: 78.3 ± 1.3 g, means ± SD). Six practical diets were formulated with the incorporation of betaine at the levels of 0 (control), 5, 10, 15, 20 and 25 g kg−1. Survival showed no significant differences among the treatments (P > 0.05). The highest and lowest weight gain (WG) and specific growth rate (SGR) were observed for fish fed the diets containing 5 and 0 g kg−1 (control) betaine, respectively. Feed intake showed similar trend with WG and SGR. In contrast, feed conversion ratio was the lowest when dietary betaine level was 5 g kg−1. In general, dietary betaine supplementation showed no significant effect on hepatic composition of tilapia. Condition factor and viscerosomatic index tended to increase with increasing dietary betaine levels from 0 to 5 g kg−1 and then decline when dietary betaine levels further increased from 5 to 25 g kg−1. In contrast, hepatosomatic index declined with increasing dietary betaine levels (P < 0.05). Dietary betaine levels significantly influenced several hepatic enzymatic activities, including succinate dehydrogenase, lactate dehydrogenase, malic dehydrogenase, lipoprotein lipase and hepatic lipase, suggesting that dietary betaine addition had significant effects on nutrient metabolism in the liver. Based on the second‐order polynomial regression analysis of WG, 12.5 g kg−1 of dietary betaine level seemed optimal for genetically improved farmed tilapia strain of O. niloticus. 相似文献
96.
D. J. Gilroy O. P. Jensen B. C. Allen S. Chandra B. Ganzorig Z. Hogan J. T. Maxted M. J. Vander Zanden 《Ecology of Freshwater Fish》2010,19(4):545-554
Gilroy DJ, Jensen OP, Allen BC, Chandra S, Ganzorig B, Hogan Z, Maxted JT, Vander Zanden MJ. Home range and seasonal movement of taimen, Hucho taimen, in Mongolia.Ecology of Freshwater Fish 2010: 19: 545–554. © 2010 John Wiley & Sons A/S Abstract – Taimen, Hucho taimen, is the world’s largest salmonid and a prized sport fish. We used radio and acoustic telemetry to characterise movements of adult taimen in an extensive river system, the Eg–Uur, in north‐central Mongolia. Forty‐six taimen were tagged with transmitters (27 radio, 17 acoustic and 2 radio‐acoustic combined) and tracked from 2004 to 2008 using mobile surveys and fixed receivers. The mean home range of individual taimen tracked for an average of 2.4 years was 23 km (N = 41, range = 0.5–93.2 km). Of the fish with over 10 relocations (N = 16), 90% remained within a range of 38 km. Four distinct movement patterns were observed: (i) restricted core home range, (ii) core range with seasonal departures, (iii) core range with separate seasonal range and (iv) home range transfer. Movement was greatest in May and June (spawning and postspawning period) with another peak period of movement in September and October (water temperature cooling). 相似文献
97.
Summary. When sequential single-node shoot segments (third to fifteenth node, counting from the apex) of the perennial grass weed Paspalum distichum L. were buried in soil, new shoot growth was significantly correlated with initial segment length. Growth from the youngest segment (third), which was about 2 cm long, was only half as great as that from segments 8 to 15, which were initially 2–3·5 times longer. When 14-node shoot segments were buried in soil, the apical bud exerted a dominating influence on shoot emergence and new shoot growth of axillary buds. The degree of suppression increased gradually up to node 8 and then decreased as the distance from the apex increased. A similar result was obtained in these shoot segments following decapitation. However, the degrees and patterns of apical and bud dominance varied in shoots collected during different seasons and also in shoots with different node numbers, node position, cutting and chilling treatments. A possible role of apical and bud dominance in P. distichum in keeping aerial shocks in reserve under adverse conditions, thus providing a survival mechanism for this weed, is discussed. 相似文献
98.
Z. DUNDJERSKI 《EPPO Bulletin》1988,18(3):445-451
Macedonia is the southern boundary for the distribution of Arvicola terrestris (water vole) in the Balkan peninsula. Until recently, these voles were found in the region only sporadically, showing none of the cyclic population fluctuations characteristic of microtines in the continental part of Europe. An investigation was started in 1984 when the first visible signs of damage to rice in Ko?ansko Valley, caused by numbers of voles, were noted. Since then, population numbers have increased, reaching a density of 1000 individuals per ha on one locality. The causes of such an unexpected outbreak and the methods for determining role abundance are discussed. The construction of a dam and the extension of rice cultivation have reduced the natural habitats of both vole predators and their competitors. Increased pesticide and fertilizer usage have also affected the fauna unfavourably. Efficient control was attained by means of zinc phosphide baits, specially before the rice growing season (i. e. in winter and early spring). 相似文献
99.
The ultrastructure of the flame cell, excretory capillaries, ducts, collecting ducts, excretory bladder, and excretory pore of Brachylaimus aequans was studied 6-8 days p.i. The excretory ducts, collecting ducts and excretory bladder are provided with numerous lamellae on the luminal side. The cilia of lateral flames in the excretory ducts have a triated rootlet. The excretory pore is covered by a tegument identical with the body tegument. The syncytium of the excretory bladder is connected with the tegument of the excretory pore by means of a septate desmosome. No lipid or excretory corpuscles have been demonstrated in the excretory system. 相似文献
100.
Effects of growth stage, leaf position and temperature on adult-plant resistance of wheat infected by Puccinia recondita f.sp. tritici 总被引:2,自引:0,他引:2
Growth stage, leaf position and temperature effects on components of resistance to Puccinia recondita f.sp. tritici in wheat ( Triticum aestivum ) were studied. Inoculation of Era, Glenlea, Sinton and RL6044 plants at five growth stages showed that latent period increased and uredinium numbers decreased as each adult-plant-resistant wheat matured. Growth stage had little effect on latent period in the susceptible cultivar Morocco. No significant differences in latent period determined on the flag, flag -1 and flag -2 leaves of the same plant were observed for Era, Glenlea and RL6044. However, leaf age should be considered in assessing adult-plant resistance because the latent period of P. recondita f.sp. tritici in flag leaves of Sinton was shorter than that determined for the flag-1 and flag -2 leaves. Fewer uredinia developed on the flag -2 leaf of Glenlea than on the flag leaf. The latent period of leaf rust in Era, Glenlea, RL6044 and Morocco was significantly longer at 15°C than at 21°C, but temperature did not affect Sinton to the same degree. Uredinium size was a sensitive criterion of adult-plant resistance. Uredinium development in line RL6044 was significantly restricted at 15°C, but uredinia on Era, Glenlea and Sinton at 15°C were as large as those at 21°C. On the susceptible Morocco uredinia were larger at 15°C than at 21°C. 相似文献