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1.
The feed level of monensin which gave maximal protection from coccidial infection in broilers reared in floor pens depended on the severity of the coccidial exposure and the criteria of infection studied. With indirect seeding of pens with coccidia (light coccidial exposure), 40 ppm was as efficacious as 100 ppm in improving weight gain, lesion score, and feed conversion. Statistical analysis with direct seeding (seeder birds; severe coccidial exposure) showed that feed levels of 84 and 102 ppm gave maximal improvement of weight gain and 4-week feed conversion, respectively. Further increasing the monensin level from 100 to 121 ppm did not improve weight gain and feed conversion at 8 weeks. Conversely, the relationship of plasma pigmentation and total lesion scores to monensin feed levels indicated that increasing the dosage of monensin from 100 to 121 ppm improved the performance of the broilers on the basis of these 2 infection indicators.  相似文献   

2.
This experiment was an attempt to use the soybean residue derived from the production of "soy milk". The residue contains about 18% protein, 70% carbohydrates and 7.5% lipid as fish feed for rearing common carp, Cyprinus carpio. There were 4 types of diets: (1) soybean residue, (2) soybean residue digested with Papain, (3) soybean residue (64%) mixed with beef liver (34%) and (4) same mixture as (3) but digested with Papain. The results indicate that the percentage increase in weight and length of fish feeding with beef liver supplemented diets was higher than those feeding with soybean residue alone. This was possibly due to the fact that beef liver was able to supplement the nutrient deficiency in soybean. The two types of feeds (2 and 4) digested with Papain also yielded significantly better fish growth in terms of weight and length gains, than their counterparts without digestion. Furthermore, the water turbidity of the tanks added with digested feeds was significantly less, as Papain was able to hyrolyse the protein substrates suspended in the water, and thus lowered the turbidity.  相似文献   

3.
Virginiamycin (VM), a compound with proven performance-promoting properties in pigs, can also be considered as sow performance enhancer. The present dose titration study investigates the long-term effects of VM on gilt/sow and litter performance. A total of 140 healthy gilts, in 35 sets of 2 + 2 siblings each, were used in this trial; gilts in each set were randomly allocated to the four treatments (35 gilts per each treatment group): VM0 = negative control, virginiamycin 0 mg/kg, VM20 = virginiamycin 20 mg/kg, VM40 = virginiamycin 40 mg/kg and VM60 = virginiamycin 60 mg/kg of feed. VM was added to the gilt/sow feed for a period starting from 6 months of age up to conception of the fourth parity, covering three complete breeding cycles (pregnancy, lactation and weaning-to-conception interval). The feed given did not contain any other antibacterial agent or performance enhancer. Piglets were given exactly the same quantity of creep feed from the fifth day onwards; it did not contain any antibacterial agent or performance enhancer. The lactation period was the same in all gilts/sows (21 days). Results indicate that VM supplementation of the feed improved gilt/sow performance by: (i) increasing (P < 0.05) the mean body weight at each farrowing, (ii) decreasing (P < 0.05) the mean weight loss from farrowing to weaning, and (iii) decreasing (P < 0.05) the mean weaning-to-conception intervals. VM supplementation of gilt/sow feed also resulted in improved litter size and litter performance in terms of: (i) a higher (P < 0.05) mean number of piglets born alive at each birth, (ii) a higher (P < 0.05) mean number of piglets weaned, (iii) a higher (P < 0.05) mean piglet body weight at each birth, and (iv) a higher (P < 0.05) mean piglet body weight at each weaning. These beneficial effects of VM were more pronounced in the VM40 group.  相似文献   

4.
The effect of dietary Arg:Lys ratios and dietary electrolyte balance (DEB) on growth and carcass parameters of Large White toms was evaluated in one experiment from 8 to 20 wk of age. Growth, feed conversion, and carcass composition were measured. All toms received a common basal diet from 0 to 8 wk of age. At 8 wk of age, 600 toms were randomly placed into 40 pens (15 toms per pen). The corn-soybean meal-based experimental diets were fed from 8 to 12, 12 to 16, and 16 to 20 wk of age and evaluated two Arg:Lys ratios (0.98 vs 1.22) and two DEB levels (148 vs 202 mEq/kg of diet) in a complete factorial arrangement. All experimental diets were pelleted. Composite samples of protein-contributing ingredients and complete experimental diets were analyzed for all amino acids, CP, DM, Cl, Na, and K. High and low average house temperature for the 8 to 20 wk period were 19 and 15 C, respectively. No interactions occurred between Arg:Lys ratios and DEB for any parameter measured except litter moisture. Increasing the Arg:Lys ratio improved 20-wk BW (P < or = 0.027) and 8 to 20 wk gain (P < or = 0.023). Feed:gain from 0 to 20 wk of age was decreased by increasing the Arg:Lys ratio (3.01 vs 2.94; P < or = 0.026) and by increasing the DEB (3.01 vs 2.95; P < or = 0.045). Dietary treatments did not affect mortality. Increasing DEB decreased cold carcass yield (P < or = 0.020). Total breast meat yield was increased (P < or = 0.076) by 1% in toms fed the diets containing the 1.22 Arg:Lys ratio vs toms fed diets containing the 0.98 Arg:Lys ratio. Toms responded favorably to increasing the Arg:Lys ratio for growth, feed conversion, and breast meat yield independent of DEB level.  相似文献   

5.
A numerical model for Type I circular sedimentation tanks (center feed) has been developed to provide useful information for circular tank operation. The unsteady flow process in circular sedimentation tanks is divided by numerous time intervals in which flow and sediment transport are considered to be steady. The other feature for this model is that particle size distribution of raw water is nonuniform. A numerical experiment based on the proposed model is carried out, and the results were compared with results from other models. The comparison shows that this model can provide more information, such as variations of water elevation, overall removal efficiency, bottom sludge thickness, and particle size distribution at outlet. In addition, this model had the advantage of optimizing the tank dimensions based on the sludge raking frequency and preferred removal efficiency. After simplification of the model, this model is practical in determining the overall removal efficiency and dimension of the tank based on different inflow situations for tank design.  相似文献   

6.
An experiment was designed to verify the effect of dietary NaHCO3 supplementation on performance of guinea fowl raised under high environmental temperatures (23.8 to 33.9 C) and average relative humidity of 78.7%. One hundred and forty guinea fowl in their final period of growth (56 to 84 d of age) were allotted to individual wire cages. Five isocaloric (3,000 kcal ME/kg) 16% CP diets based on corn and soybean meal and containing 0, 0.6, 1.2, 1.8, and 2.4% sodium bicarbonate were fed to the birds. The experiment followed a randomized block design with 28 birds per treatment (14 of each sex) with each bird being considered as one repetition. Results showed that weight gain, feed intake, feed conversion, mortality, blood pH, carcass yield, and carcass composition were not affected (P > 0.05) by dietary sodium bicarbonate supplementation. Weight gain, feed intake, feed conversion, carcass moisture, and fat content, however, were significantly (P < 0.05) affected by sex. Females showed 17.49% better weight gain, 7.16% greater feed intake, and 9.6% better feed conversion than males. These differences were exacerbated at supplementation levels of 1.2 and 1.8% sodium bicarbonate in the diet. Male birds showed carcass moisture values significantly (P < 0.05) greater than those of female birds; the opposite occurred with carcass fat levels. The use of sodium bicarbonate in levels up to 2.4% of the diet did not affect the performance of guinea fowl raised under the environmental conditions registered in this study.  相似文献   

7.
酸洗槽是去除热轧板表面氧化铁皮的主体设备,传统酸洗槽设计多选用碳钢衬胶再衬耐酸砖结构,制造工序复杂,维护困难。近年来,聚丙烯(PP)材质以其优越的机械加工性能和耐化学品性能得到广泛应用。对比PP酸洗槽和传统钢衬胶再衬砖结构,PP酸洗槽质量轻,便于运输、安装和质量控制,在越来越多的新旧生产线上取代传统的钢结构形式。分析PP酸洗槽设计方面纵向热膨胀以及回酸口的焊接问题,给出了解决的方案,并展望了PP酸洗槽的应用前景。  相似文献   

8.
The effects of L-carnitine supplementation (50-500 mg/kg diet) of a practical layer diet, based on maize, soyabean and wheat, on the performance of laying hens and some indices of egg quality were studied for 8 weeks, using 65-week-old hens kept in cages. Albumen quality (albumen height and Haugh (1937) unit score) was improved, while yolk index and yolk colour score were not affected by dietary L-carnitine. The percentage of egg-white increased and that of egg yolk decreased in response to dietary supplementation of L-carnitine. Dietary L-carnitine did not influence laying performance (egg production rate, mean egg weight, daily feed intake, daily egg mas and feed conversion) or external egg quality measured by egg weight, egg-shape index or by eggshell quality, either measured directly as shell breaking strength or indirectly as shell weight, shell thickness or shell weight per unit surface area. Based on the results of the present study, L-carnitine had a beneficial effect on albumen quality and could modify the components of the edible part of the egg, during the late laying period.  相似文献   

9.
Conducted 8 experiments to investigate the reproductive and agonistic behaviors of Siamese fighting fish and isolated some consequences and determinants of these sequences. Fights and the formation of dominance–subordinancy relations were studied, using 536 pairs of male fish. The effect and magnitude of prior residency, the importance of body length, chemical cues, and intratank visual/tactile clues were observed. Findings indicate that large body size as well as Ss' prior residency in a tank produced an agonistic advantage; the magnitude of this advantage was positively related to the duration of residency. The prior-residency effect in Bettas was determined by Ss' familiarity with visual and/or tactile cues in their home tanks. Dominant males had greater access to living space and were more likely to display at a mirror, build nests, and approach females than were subordinates. Finally, it was discovered that chemical cues associated with presumedly inert plastic tank dividers influenced Bettas's social behavior. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

10.
Small reservoirs known as tanks are constructed in the watersheds of arid, semiarid, and subhumid regions of India to provide supplementary or protective irrigation to crops during dry spells of the monsoon season or full irrigation during the postmonsoon season. The stored water in tanks or recharged groundwater is used for this irrigation. Several models have previously been developed to design the capacity of individual tanks. However, for optimum utilization of water generated in a watershed to meet the demands for irrigation and for downstream release, it is necessary to design the tanks together in terms of their number, locations, and capacities. A comprehensive methodology for this is presented using stream points, i.e., possible tank locations on the main stream(s) in the watershed. Tank strategies (combinations of numbers of tanks, their locations at stream points, and tank types) are then generated for the identified stream points. Subsequently, fields in the watershed are assigned to the catchment and the command of different tanks of a specified tank strategy. Simulation of field, tank, and groundwater balance is then carried out on a daily basis, from which optimum tank dimensions are obtained for a specified tank strategy. The optimum tank strategy and corresponding optimum tank dimensions are obtained by investigating all the possible tank strategies.  相似文献   

11.
Although the feed-conversion ratio is recognized as a prominent indicator of profitability for pork producers, only 212 (50.7%) of 418 producers who were asked the feed-conversion ratio for finisher pigs provided a response during the USA National Animal Health Monitoring System 1995 National Swine Study. Of these, 126 (59.4%) producers furnished a feed-conversion ratio which they characterized as having been calculated from records, while 86 (40.6%) gave a response that they characterized as estimated or guessed. Feed-conversion ratios ranged from 2.18 to 5.91 kg of feed fed for each kg of live-body weight gained during the grower/finisher phase, with a mean of 3.28 and a standard deviation of 0.52. Stepwise regression revealed the following management factors to be associated with improved feed-conversion ratios: > or = 3 different rations fed during the grower/finisher phase (P < 0.01); no rations mixed on the farm (P < 0.05); and not giving chlortetracycline in feed or water as a disease preventive or growth promotant (P < 0.01). In addition, operations where > or = 3000 pigs entered the grower/finisher-production phase during the six-month period prior to interview had a better mean feed-conversion ratio than operations where < 3000 pigs entered the grower/finisher phase (P < 0.01).  相似文献   

12.
Growth hormone binding protein (GHBP) may be an important factor in the regulation of growth and might provide an indirect, relatively noninvasive means of predicting the status of hepatic growth hormone receptor (GHR) activity. Several factors have been reported to influence growth hormone (GH), GHR, or GHBP. Therefore, these studies were conducted to test how age, sex, nutritional status, and glucocorticoids (cortisone acetate, CA) influence serum concentrations of chicken GHBP. Serum GHBP activity was highest (mean percentage specific binding (%SB) = 12.43 +/- .80) at hatch and decreased linearly (P < .0001) to 5 wk of age (%SB = 1.99 +/- 1.13). There were no sex-related differences in serum GHBP activity from hatch to 5 wk of age (P > .08). Short-term nutrient deprivation (24-h) of 4-wk-old broilers also had a significant effect on serum GHBP activity (P < .0001). Measurement of serum GHBP activity with refeeding (after a 24-h period without feed) restored %SB to normal values. Feeding broilers a low-protein diet (12% CP) did not significantly affect serum GHBP activity when compared with that of broilers fed a commercial broiler diet (23% CP; P > .30). Administration of cortisone (1, 5, and 10 mg/day), every 24 h for 7 days, had no effect, at any dose, on serum GHBP activity at 48 h and 1 wk after the last injection. These results indicate that serum GHBP activity is influenced by factors such as age and feed deprivation. It remains to be determined whether these changes in GHBP are associated with changes in GHR as reported for mammalian species.  相似文献   

13.
A 3-wk feeding trial with 240 sexed, day-old broiler chickens was conducted to determine the efficacy of microbial phytase at different levels of dietary Ca on performance and utilization of minerals in broiler chickens fed a low-P corn-soybean diet. The experimental design was a 3 x 2 factorial arrangement of treatments; Ca at 0.6, 1.0, and 1.25% and phytase at 0 and 600 phytase U/kg diet. Phytase supplementation, regardless of Ca level, increased (P < or = 0.005) feed intake, (P < or = 0.0001) body weight, and (P < or = 0.025) feed efficiency at 21 d; the optimum levels of body weight, feed intake, and feed efficiency were obtained with low (0.6%) dietary Ca plus phytase. Retentions of P, Ca, and N were increased (P < or = 0.05) by phytase supplementation. Although maximum retentions of P and N were obtained at the 1.0 and 1.25% Ca levels, respectively, they were not significantly different from the values obtained at 0.6% Ca. The increasing level of dietary Ca decreased plasma P ( P < or = 0.05) and Cu (P < or = 0.06). Phytase supplementation had the opposite effect; i.e., increased plasma P (P < or = 0.03) and Cu (P < or = 0.02). The maximum level of plasma P was obtained with phytase at the 1.0% Ca level, but this value was not significantly different from the value obtained with phytase at the 0.6% Ca level. Phytase supplementation increased (P < 0.04) the ash content of both tibia head and shaft but had no effect on mineral contents in the ash. The optimum level of ash content was observed with the 0.06% Ca diet plus phytase. The results show that microbial phytase supplementation to a low P diet improved growth performance and mineral utilization in broiler chickens. Dietary Ca levels had a significant effect on the response to phytase; the optimum growth performance and mineral utilization were achieved at the low (0.6%) level of dietary Ca supplemented with phytase.  相似文献   

14.
OBJECTIVES: To describe the patterns of growth, nutritional status, body composition, and resting energy expenditure (REE) in prepubertal children with Alagille syndrome (AGS) before the onset of end-stage liver disease. STUDY DESIGN: Thirteen prepubertal subjects with AGS (8 male; mean age, 6.8 2.8 years) were evaluated for growth parameters, body composition by skinfolds and by dual-energy x-ray absorptiometry, and REE by indirect calorimetry. The children with AGS were compared with a healthy, age-matched reference group of 37 prepubertal children. RESULTS: Compared with healthy children, children with AGS had significantly reduced (P <. 05) growth (weight, weight z score, height, height z score), nutritional status (midarm circumference, triceps skinfold, and midarm muscle area), and body composition (fat mass and fat-free mass). Subscapular thickness, percent body fat, and REE were not different. The AGS subgroup (n = 4) with REE greater than 110% predicted value had a reduced percent body fat (P <.02). CONCLUSIONS: Growth and body composition abnormalities are common in prepubertal children with AGS.  相似文献   

15.
We measured the effect of duration of feed quality restriction and the consequent compensatory growth on body dimensions in 18 crossbred Swifter (Texel sire x Flemish dam) male lambs born in March 1994 and weaned at approximately 2 mo of age. The lambs were fed grass straw (46 g CP/kg DM) for ad libitum consumption and 35 g CP x kg(-75) x d(-1) mixed concentrates (173 g/kg DM). At approximately 3.5 mo of age and average live weight of approximately 34 kg, the lambs were allotted to six blocks, each block with three lambs of approximately the same live weight. Within each block, the three lambs were then randomly assigned to two restricted treatments (R1 and R2) and a control (C) treatment. In treatments R1 and R2, feed quality was restricted by withholding concentrates for 3 and 4.5 mo, respectively. A growth model was developed to study the effects of restriction and subsequent compensation after realimentation (6.5 and 8 mo for R1 and R2 groups, respectively). During restriction, live weight and growth in body dimensions were suppressed. Bone length measures such as body length and ulna length were less affected than live weight. The response in testes girth to restriction was almost immediate. At the end of the experiment (age of about 14 mo), R1 animals fully compensated. However, the R1 animals had higher testes girth (P < .001), chest girth (P < .01), and chest depth (P < .05). Extending the duration of feed restriction did not have a significant effect on the rate of losses in live weight and body dimensions during restriction. At the end of the experiment, except for withers height and trunk length, the R2 animals did not compensate fully in live weight and other dimensions. However, the parameter estimates suggested that the R2 animals may need a relatively longer period of realimentation to reach to the same size as R1 and C animals.  相似文献   

16.
Two trials were carried out to test the susceptibility for metabolic disturbances of different strains of male broilers. In Trial 1, 1,890 male chickens were allotted in a randomized block design with seven treatments (Arbor Acres, Avian Farms, Cobb-500, Hubbard-Peterson, ISA, Naked Neck, and Ross) and six blocks of 45 chickens. Trial 2 involved 2,184 male chickens of six strains (Arbor Acres, Avian Farms, Cobb 500, Hubbard-Peterson, ISA Naked Neck, and Ross) allotted in seven complete blocks of 52 birds. The same management system was adopted for all birds, reared up to 42 d in an open house during late winter (Trial 1) or late autumn (Trial 2). The most marked differences observed among the strains tested was the lower BW and higher feed conversion of Naked Neck broilers. Total percentage mortalities were high among the most productive broilers, being more than 50% due to sudden death (SDS) and ascites syndrome (AS). No Naked Neck birds died as a consequence of these disturbances and the total mortalities were significantly lower (P < or = 0.05) than the other strains. The ratio of right ventricle weight to total ventricle weight of the dead birds was over 0.25, except for Naked Neck birds, which presented a nonhypertrophic ratio. The two trials confirmed the relationship between high productivity and high incidence of SDS and AS and indicated that Naked Neck male broilers are resistant to these metabolic disturbances.  相似文献   

17.
OBJECTIVE: The triglyceride-lowering effects of omega-3 fats and HDL cholesterol-raising effects of exercise may be appropriate management for dyslipidemia in NIDDM. However, fish oil may impair glycemic control in NIDDM. The present study examined the effects of moderate aerobic exercise and the incorporation of fish into a low-fat (30% total energy) diet on serum lipids and glycemic control in dyslipidemic NIDDM patients. RESEARCH DESIGN AND METHODS: In a controlled, 8-week intervention, 55 sedentary NIDDM subjects with serum triglycerides > 1.8 mmol/l and/or HDL cholesterol < 1.0 mmol/l were randomly assigned to a low-fat diet (30% daily energy intake) with or without one fish meal daily (3.6 g omega-3/day) and further randomized to a moderate (55-65% VO2max) or light (heart rate < 100 bpm) exercise program. An oral glucose tolerance test (75 g), fasting serum glucose, insulin, lipids, and GHb were measured before and after intervention. Self-monitoring of blood glucose was performed throughout. RESULTS: In the 49 subjects who completed the study, moderate exercise improved aerobic fitness (VO2max) by 12% (from 1.87 to 2.07 l/min, P = 0.0001). Fish consumption reduced triglycerides (0.80 mmol/l, P = 0.03) and HDL3 cholesterol (0.05 mmol/l, P = 0.02) and increased HDL2 cholesterol (0.06 mmol/l, P = 0.01). After adjustment for age, sex, and changes in body weight, fish diets were associated with increases in GHb (0.50%, P = 0.05) and self-monitored glucose (0.57 mmol/l, P = 0.0002), which were prevented by moderate exercise. CONCLUSIONS: A reduced fat diet incorporating one daily fish meal reduces serum triglycerides and increases HDL2 cholesterol in dyslipidemic NIDDM patients. Associated deterioration in glycemic control can be prevented by a concomitant program of moderate exercise.  相似文献   

18.
Methionine requirement of channel catfish fed soybean meal-corn-based diets   总被引:2,自引:0,他引:2  
A soybean meal-corn-based diet was used to determine dietary methionine (Met) required by 14-g channel catfish (Ictalurus punctatus) in a 42-d experiment at 25 degrees C. The basal diet with balanced limiting amino acids relative to the catfish whole-body amino acid profile contained 277 g of CP, 3.6 g of Met, 4.0 g of cystine (Cys), and 10 MJ of DE/kg of DM. DL-Methionine was added to the basal diet from 0 to 12.0 g/kg in 2-g intervals at the expense of L-glutamic acid to produce seven isonitrogenous and isocaloric diets. A reference diet contained 331 g of CP, 8 g of Met, 5 g of Cys, and 10 MJ of DE/kg of DM (included 8% fish meal). Seven graded Met levels resulted in quadratic responses (P < .01) of weight gain, specific growth rate, feed or GE intake, feed or energy efficiency, protein or energy retention, protein efficiency ratio, and apparent net protein or energy utilization. Channel catfish required 9.4 g of Met/kg of DM (34.1 g/kg of CP) with a total 11.3 g/kg of calculated digestible sulfur-containing amino acids based on multiple regression dose-response models or 270 mg of Met/kg of fish per day based on a broken-line response of protein gain to Met intake. At the adequate Met level, catfish with the lowest (P < .05) liver lipids showed feed intake and protein or energy utilization efficiency similar (P > .05) to that of catfish fed the reference diet. Catfish fed all-plant-protein diets require more dietary methionine than previously reported. Catfish fed corn-soybean meal diets fortified adequately with methionine result in performance that approaches that of fish fed a fish meal-based diet.  相似文献   

19.
Pipe network computer models of water systems that include hydropneumatic tanks can be used to evaluate performance of existing water systems or in the design of new distribution facilities. Pipe network models allow the modeling of storage tanks in which the free water surface is variable with the inflow and outflow. Most existing pipe network models do not allow direct input of hydropneumatic tanks. Some writers describe modeling of hydropneumatic tanks as a fixed diameter tank of an equivalent area based on the maximum and minimum operating pressures of the tank. In real hydropneumatic tanks, the pressure change due to input or output of water is greater as more water is stored in the tank. A relationship to define the geometry of a free water surface tank that would exactly simulate a hydropneumatic tank was derived which can be input into a pipe network model using the variable area tank feature.  相似文献   

20.
Retrospective analysis of an anthropometric database collected prospectively in children with cerebral palsy (CP) was carried out to evaluate linear growth velocity and identify risk factors for poor linear growth. Growth velocity measures were compared with published norms for prepubertal growth velocity and z scores were calculated. Mean growth velocity z score (Gvz) was -0.97+/-1.9. Boys grew more slowly than girls (mean Gvz = -1.5+/-1.9 versus -0.3+/-1.7 P = 0.003). Gvz did not correlate with type of CP or presence/absence of microcephaly. Young age was a risk factor for poor linear growth (mean Gvz = -2.40+/-2.6 for children under 2 years of age versus -0.76+/-1.9 ages 2 to 6 and -0.77+/-1.6 ages 6 to 10, P = 0.04). Children at nutritional risk (triceps skinfold thickness < or =55%) grew poorly (mean Gvz = -1.46+/-1.5 versus -0.30+/-1.8, P = 0.01). For children over 2 years, those with cognitive impairments grew more slowly than those with normal cognition (mean Gvz = -1.25+/-1.9 versus -0.12+/-1.8, P = 0.02) and non-ambulatory children grew more slowly than ambulatory children (mean Gvz = -1.20+/-1.5 versus -0.35+/-1.9, P = 0.03). Prepubertal children with CP grow more slowly than expected compared with age- and sex-based standards. Sex, age, cognitive impairment, ambulatory status, and nutritional state are factors which may contribute to slow growth. These results add to the growing data that children with CP have unique growth patterns. Further study is needed to clarify the factors which contribute to poor linear growth in this population.  相似文献   

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