首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9篇
  免费   2篇
  3篇
农作物   2篇
水产渔业   2篇
畜牧兽医   4篇
  2016年   1篇
  2015年   2篇
  2014年   3篇
  2013年   3篇
  2008年   2篇
排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
To investigate the effects of different sources of carbohydrates on intake, digestibility, chewing, and performance, nine lactating Holstein dairy cows (day in milk= 100±21 d; body weight=645.7 ± 26.5 kg) were allotted to a 3 × 3 Latin square design at three 23-d periods. The three treatments included 34.91% (B), 18.87% (BC), and 18.86% (BB) barley that in treatment B was partially replaced with only corn or corn plus beet pulp in treatments BC and BB, respectively. The concentration of starch and neutral detergent soluble carbohydrate varied (22.2, 20.2, and 14.5; 13.6, 15.9, and 20.1% of DM in treatments B, BC, and BB, respectively). Cows in treatment BB showed a higher DMI and improved digestibility of DM, NDF, and EE compared with treatments B or BC. Ruminal pH was higher in cows fed on BB (6.83) compared with those that received B or BC treatments (6.62 and 6.73, respectively). A lower proportion of propionate accompanied the higher pH in the BB group; however, a greater proportion of acetate and acetate: propionate ratio was observed compared with cows fed either on the B or BC diet. Moreover, cows fed on the BB diet showed the lowest ruminal passage rate and longest ruminal and total retention time. Eating time did not differ among treatments, rumination time was greater among cows fed on the BB diet compared with the others, whereas total chewing activity was greater than those fed on BC, but similar to those fed on B. The treatments showed no effect on milk yield. Partially replacing barley with corn or beet pulp resulted in an increase in milk fat and a lower protein concentration. Changing dietary NFC with that of a different degradability thus altered intake, chewing activity, ruminal environment, retention time or passage rate, and lactation performance. The results of this study showed that beet pulp with a higher NDF and a detergent-soluble carbohydrate or pectin established a more consistent ruminal mat than barley and corn, thus resulting in higher mean retention time and chewing activity, whereas no changes in 3.5% FCM and milk fat were observed.  相似文献   
2.
A greenhouse research experiment was conducted to investigate the effect of salinity stress and potassium (K) fertilization on biomass accumulation of roots and shoot of saffron plants. Treatments were four levels salinity in the form of sodium chloride (NaCl; 3.4, 6.4, 9.4 and 12.4 dS m?1) and three levels of potassium (50, 100, and 150 % of Hoagland's nutrition solution base). Results indicated that higher levels of potassium significantly controlled the negative effects of NaCl on length and number of roots as well as fresh weight and number of leaves per plant. Increase in salinity and potassium levels caused a reduction in leaf water content, and enhancement in electrolyte leakage. It seems that in the presence of salinity increasing 50% extra potassium (Based on Hoagland's nutrient solution) in the rhizosphere of saffron can improve damaging effects of NaCl up to 9.4 dS m?1 of soil solution.  相似文献   
3.
The main aim of this study was to evaluate the effects of dextromethorphan and midazolam and their combination on morphine tolerance and dependence in mice. In the present study, different groups of mice were rendered randomly and received morphine (50 mg kg(-1), s.c.), morphine (50 mg kg(-1), s.c.) + Dextromethorphan (25, 50 and 75 mg kg(-1), i.p.), morphine (50 mg kg(-1), s.c.) + midazolam (0.5, 1 and 2 mg kg(-1), i.p.), morphine (50 mg kg(-1), s.c.) + [Dextromethorphan (25 mg kg(-1), i.p. ) + midazolam (0.5 mg kg(-1), i.p.)] once a day for four days. Tolerance was assessed by administration of morphine (9 mg kg(-1), i.p.) on fifth day. Withdrawal symptoms (markers for dependence) was assessed by administration of naloxone (4 mg kg(-1), i.p.) 2 h after co-administration of morphine with either Dextromethorphan or midazolam or their combination. Results showed that pretreatment with Dextromethorphan or midazolam decreased the degree of tolerance and withdrawal symptoms significantly. Additionally co-administration ofDextromethorphan and midazolam couldn't decreased the tolerance and dependence significantly. From these results it may concluded that Dextromethorphan and midazolam alone or in combination could prevent the development of morphine induced tolerance and dependence. These effects can be related to the N-Methyl-D-Aspartate (NMDA) receptor antagonist behavior of Dextromethorphan and GABA-receptor agonist property of midazolam.  相似文献   
4.
To investigate the effects of different sources of carbohydrates on intake, digestibility, chewing, and performance, nine lactating Holstein dairy cows (day in milk= 100±21 d; body weight=645.7 ± 26.5 kg) were allotted to a 3 × 3 Latin square design at three 23-d periods. The three treatments included 34.91% (B), 18.87% (BC), and 18.86% (BB) barley that in treatment B was partially replaced with only corn or corn plus beet pulp in treatments BC and BB, respectively. The concentration of starch and neutral detergent soluble carbohydrate varied (22.2, 20.2, and 14.5; 13.6, 15.9, and 20.1% of DM in treatments B, BC, and BB, respectively). Cows in treatment BB showed a higher DMI and improved digestibility of DM, NDF, and EE compared with treatments B or BC Ruminal pH was higher in cows fed on BB (6.83) compared with those that received B or BC treatments (6.62 and 6.73, respectively). A lower proportion of propionate accompanied the higher pH in the BB group; however, a greater proportion of acetate and acetate: propionate ratio was observed compared with cows fed either on the B or BC diet. Moreover, cows fed on the BB diet showed the lowest ruminal passage rate and longest ruminal and total retention time. Eating time did not differ among treatments, rumination time was greater among cows fed on the BB diet compared with the others, whereas total chewing activity was greater than those fed on BC, but similar to those fed on B. The treatments showed no effect on milk yield. Partially replacing barley with corn or beet pulp resulted in an increase in milk fat and a lower protein concentration. Changing dietary NFC with that of a different degradability thus altered intake, chewing activity, ruminal environment, retention time or passage rate, and lactation performance. The results of this study showed that beet pulp with a higher NDF and a detergent-soluble carbohydrate or pectin established a more consistent ruminal mat than barley and corn, thus resulting in higher mean retention t  相似文献   
5.
ABSTRACT

Nickel (Ni) is an essential element for activation of urease in higher plants. The effects of Ni as an essential micronutrient on growth and chlorophyll content of wheat plants grew in nutrient solutions supplied either with ammonium nitrate or urea as two different nitrogen (N) sources were investigated. Plants were allowed to grow for six weeks, then leaf chlorophyll content, shoot and root fresh and dry weights, and Ni concentration in shoots and roots were determined. Shoot and root Ni concentration in both urea and ammonium nitrate-fed plants increased significantly with the increase in Ni concentration. Growth and chlorophyll content in leaves of the urea-fed plants increased when Ni concentration in the solution was as high as 0.05 mg L?1 and decreased at 0.1 mg Ni L?1. In ammonium nitrate-fed plants, these parameters increased up to 0.01 mg Ni L?1 and started to decrease with further increase in Ni concentration. Plants that grew in nutrient solutions containing urea had more shoots and roots fresh and dry weight at third and fourth Ni levels (0.05 and 0.1 mg L?1) than those that grew in media containing ammonium nitrate with similar Ni levels. Total chlorophyll content was also higher in plants supplied with urea plus Ni. The amount of Ni required for optimum wheat growth was dependent on the forms of N used. When supplied with ammonium nitrate or urea, the amount of Ni needed was 0.01 and 0.05 mgL?1 of nutrient solutions, respectively.  相似文献   
6.
It has been previously indicated that arbuscular mycorrhizal (AM) fungi can enhance the bioremediation abilities of their host plant. Barley (Hordeum vulgare L.) is a crop plant with some unique physiological properties, such as tolerance to salinity. However, its tolerance to other stresses such as heavy metals must be tested. Accordingly, it was hypothesized that barley can be efficiently used to treat heavy metals in symbiotic and non-symbiotic association with AM fungi. In a greenhouse experiment barley plants were inoculated with the AM species Glomus mosseae and grown in a soil polluted with cadmium (Cd), cobalt (Co), and lead (Pb). Relative to Cd and Co, mycorrhizal barley absorbed significantly higher amounts of Pb. AM species also significantly decreased Cd and Co uptake by barley indicating the alleviating effects of G. mosseae on the stress of such heavy metals.  相似文献   
7.
This study evaluated the effects of diets containing 20, 40, 60, 80 and 100 mg kg?1 diet astaxanthin or canthaxanthin on Pethia conchonius (Hamilton, 1822) pigmentation. A completely randomized experimental design was developed with ten treatments and three replicates. Three hundred rosy barb with a mean weight of 0.92 ± 0.06 g were assigned to thirty aquaria for period of eight weeks. Carotenoid contents of fish fed canthaxanthin were always lower than those fed astaxanthin. Yellowness (b*) was not affected by pigments. While Luminosity (L*) decreased in fish fed astaxanthin diets, this parameter increased by feeding on canthaxanthin. The most pronounced effect was higher a* values in fish fed astaxanthin. Astaxanthin retention rate was higher than that of canthaxanthin. The present results demonstrate that canthaxanthin cannot be considered as a proper replacement with astaxanthin. Inclusion of 80 and 100 mg astaxanthin kg?1 diet can be suitable dietary levels to ensure pigmentation and this condition may improve market value of rosy barb.  相似文献   
8.
This study tried to determine the protein and energy requirements of growing beluga sturgeon Huso huso using a factorial approach. The experiment was composed of four small‐scale growth trails covering different weight ranges. The fish fed at 0, 20, 40, 60, 80 and 100% of satiation. DWG had a steady increase throughout the experiment following a non‐linear equation as Y = 1.433 (±0.056) × Ln(X) ?2.740 (±0.261); r2 = 0.99, p < 0.001, where Y = weight gain (g/day) and X = fish weight (g). The daily requirement of digestible energy (DE) for maintenance amounted to 79.09 kJ × BW (kg)0.8. The daily requirement of DP for maintenance calculated as 0.93 g × BW (kg)0.7. The relationship between DE intake (X) and DE gain (Y) expressed as Y = ?0.0004 (±0.000) X2 + 0.600 (±0.082) X ?44.95 (± 6.72). Also, the relationship between DP intake (X) and protein gain (Y) was expressed as Y = ?0.019 (±0.006) X2 + 0.548 (±0.062) X ? 0.498 (±0.121). The daily requirements of energy and protein were estimated as 79.09 kJ × BW (kg)0.8 + 2.94 × DE gain and 0.93 g × BW (kg)0.7 + 2.63 × DP gain. Apparently, beluga sturgeon is inefficient in converting energy and protein into body tissue. Therefore, energy content of the diet should be sufficiently high to satisfy large energy demands in beluga sturgeon and also to reduce the catabolism of protein.  相似文献   
9.
This study evaluated the effects of diets containing 0, 25, 50, 75 and 100 g kg?1 Spirulina platensis on proximate composition, fatty acid profile and lipid peroxidation of rainbow trout (Oncorhynchus mykiss). Supplementation of S. platensis did not change moisture and protein contents, but fish fed 50 and 100 g kg?1 S. platensis had lower muscle lipid content than those fed control diet (< 0.05). Fish fed 100 g kg?1 of S. platensis contained lower percentages of saturated and monounsaturated fatty acid and a higher percentage of polyunsaturated fatty acid than those fed control diet (< 0.05). The n‐3/n‐6 ratio of the fatty acid increased and muscle atherogenic and thrombogenic indices were significantly decreased as the dietary supplement of S. platensis increased. Furthermore, lipid peroxidation of the fillet significantly decreased with increasing dietary S. platensis at 4 °C and at ?20 °C (< 0.05). The results of this study show that supplementation of S. platensis to the diet improves muscle quality of the rainbow trout.  相似文献   
10.
This study investigated the effect of a new microbial inoculant product on the composition and nutritive value of corn silage in big silo over one year that used beef cattle. Six Holstein beef steer (BW = 225 +/- 17) were allotted to 2 x 2 repeated Latin square design at two 21 days periods (adaptation, 14 days and sample collection, 7 days) for evaluation the effect of microbial inoculation on the composition and nutritive value of corn silage for beef cattle. Two treatments, forages were untreated or treated at ensiling with Lactobacillus plantarum and Propionibacterium acidipropionici silage inoculants. After 45 days from ensiling, the ration that contained 94.5 and 5, 0.2, 0.2, 0.1% of DM silage and ground barely, mineral-vitamin, dicalcium phosphate, salt, respectively, were offered for free choice consumption. Treatment with Lactobacillus plantarum and Propionibacterium acidipropionici inoculant increased daily dry matter intake and subsequently NDF, ether extract, crude protein and ash. Apparent digestibility of DM and nutrients were significantly increased by microbial inoculation. Microbial inoculation can improve the nutritive value of corn silage for beef cattle.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号