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   70篇
  免费   3篇
林业   7篇
农学   1篇
  5篇
综合类   1篇
农作物   4篇
水产渔业   2篇
畜牧兽医   46篇
园艺   2篇
植物保护   5篇
  2022年   2篇
  2021年   3篇
  2020年   1篇
  2019年   3篇
  2018年   2篇
  2017年   1篇
  2016年   5篇
  2015年   2篇
  2014年   2篇
  2013年   3篇
  2012年   3篇
  2011年   4篇
  2010年   3篇
  2009年   3篇
  2008年   6篇
  2007年   3篇
  2006年   5篇
  2005年   2篇
  2004年   4篇
  2003年   2篇
  2002年   1篇
  2000年   1篇
  1999年   2篇
  1997年   3篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1986年   1篇
  1984年   1篇
排序方式: 共有73条查询结果,搜索用时 406 毫秒
1.
  1. The effects of high dose of microbial phytase and an emulsifier on the performance, apparent metabolisable energy (AME) and nitrogen (N) retention in broilers fed on diets containing different fat sources were examined in a 5-week trial. Two fat sources (soy oil and tallow), two inclusion levels of E. coli phytase (500 or 1000 phytase units (FTU)/kg diet) and two inclusion levels of lysolecithin emulsifier (0 or 3.5 g/kg of diet) were evaluated in a 2 × 2 × 2 factorial arrangement of treatments.

  2. Throughout the 5-week trial, soy oil supplementation improved weight gain and feed per gain compared with tallow, but had no effect on feed intake.

  3. The high dose of phytase increased the weight gain and feed intake and lowered the feed per gain during d 1–21, but had no effect on performance parameters over the whole trial period.

  4. An effect of emulsifier was observed for feed intake during d 1–21 and over the whole trial period. Addition of emulsifier increased feed intake compared with diets without emulsifier.

  5. During weeks 1, 2, 3 and 5, birds fed on soy oil–based diets had higher nitrogen-corrected AME (AMEN) compared with those fed on tallow-based diets. During weeks 2, 3 and 5, the effect of phytase was significant for AMEN, with the high dose increasing the AMEN. During week 2, AMEN was increased with emulsifier addition.

  6. During weeks 1, 2, 3 and 5, birds fed on soy oil–based diets had higher fat retention compared with those fed on tallow-based diets. The high dose of phytase improved the retention of fat during week 5 and the addition of emulsifier resulted in higher fat retention during week 1.

  7. During weeks 2, 3 and 5, an interaction between fat source × phytase × emulsifier was observed for N retention. In soy oil–based diets, emulsifier plus 1000 FTU/kg phytase increased N retention compared with other groups, while in tallow-based diets, emulsifier addition increased N retention in diets with 500 FTU/kg, but not in 1000 FTU/kg diet.

  8. Overall, the present data suggest that the dietary fat source influenced performance, AMEN and fat retention in broiler chickens. There is opportunity to improve bird performance during d 1–21, AMEN and fat retention with higher doses of microbial phytase. Addition of the emulsifier increased the AMEN during week 2 and tract retention of fat during week 1, but this effect was not translated into improvements in performance.

  相似文献   
2.
Journal of Pest Science - In Peninsular Malaysia, barn owls (Tyto javanica javanica) have been utilized as biological control of rats since the 1960s. In this study, the impact of introduced barn...  相似文献   
3.
Angkanaporn, K., Ravindran, V., Mollah, Y. and Bryden, W.L., 1997. Secretion of homoarginine into the gut of chickens. Veterinary Research Communications, 21(3), 161-167A technique, based on the homoarginine present in guanidinated proteins, has been used to distinguish between endogenous secretions and exogenous dietary amino acids in the ileal digesta of monogastric animals. This technique assumes that the ingested homoarginine is not recycled into the small intestine after absorption, but this assumption is yet to be experimentally validated in chickens. The secretion of homoarginine into the gut of broilers that were intravenously infused with 20 and 40 mmol/L homoarginine solutions was assessed. The plasma concentrations of homoarginine increased with increasing concentrations of homoarginine infused. However, only negligible levels of homoarginine (7.0 to 45.2 µg/g dry matter) were found in the digesta. Less than 0.01% of the intravenously infused homoarginine was recovered in the intestinal digesta, indicating that the secretion of homoarginine into the gut of chickens was insignificant.  相似文献   
4.
A field experiment was conducted from 1985–1986 to 2002–2003 on Vertisols under rainfed conditions to evaluate the effect of cropping systems and application of fertilizers and manure on seed cotton yield. To determine the long‐term effects, trends and stability analyses were performed. Soil samples (0–0.15 and 0.15–0.30 m) were collected at the end of year 18 and analysed for available P and AB‐DTPA extractable Zn. Among cropping systems, Asiatic diploid cotton (Gossypium arboreum) yielded 233 kg ha?1 more seed cotton than the upland tetraploid cotton (Gossypium hirsutum). Yield trend was positive for G. arboreum compared with G. hirsutum. However, the slope was not significant. Stability analyses indicated overall higher yield stability for G. arboreum than G. hirsutum. Compared with monocropping G. hirsutum, G. hirsutum–sorghum (Sorghum bicolor L.) (H‐S) rotation was significantly more stable. Soil samples (0–0.30 m) of the manure‐amended plots had significantly greater P and Zn content (above the critical limit) compared to those receiving inorganic fertilizers alone. With regard to nutrient management practices, seed cotton yield was the highest for the integrated nutrient management (INM) treatment receiving a combination of organic and inorganic fertilizers. Among primary nutrients, the effect of P was significant while that of K was not. Balanced fertilizer application was significantly better than treatments receiving N and NK. Yield trends were, in general, not significant. However, a positive trend was noticed for treatments receiving manure compared to fertilizer alone. Stability analysis, on the other hand, indicated that the slopes were, in general, significant. Among the nutrients, mean yield response with and without P was 1007 and 672 kg ha?1 respectively. Combined application of manure and fertilizer (INM) resulted in the highest mean yield response (1218 kg ha?1) and the slope was highly significant (P < 0.004). In the manure‐amended plots, a better nutrient status probably imparted a greater degree of yield stability. The present study suggests that compared to trend analysis, stability analysis being sensitive as it recognizes the treatment × environment interaction, is a better option to interpret results from long‐term agronomic experiments.  相似文献   
5.
Carbon sequestration potential (CSP) and sustainability of gardenpea-french bean cropping system was assessed with farmyard manure (FYM) application vis-à-vis mineral fertilization as recommended NPK (NPK) and integrated nutrient management practices (INM) after six years’ cropping in Indian Himalayas. Application of 20 tons FYM ha?1 provided highest CSP (0.527 Mg C ha?1 year?1) in soil and sustainability index. With the help of quadratic equations, it was estimated that maximum profit (optimum yield) and turn over of invested money could be achieved with application of 20.0 and 15.6 t FYM ha?1, respectively. Application of 5.9 and 8.9 tons FYM ha?1 would substitute NPK and INM, respectively. Pod number plant?1 was the most important yield-contributing attribute as found from principal component analysis. Pod yield could be modelled through multiple linear equation with help of yield attributes.  相似文献   
6.
Usually saline soils were reclamized by chemical or mechanical remediation, since the cost of leaching technique for saline soil reclamation is higher in India. In the present study an attempt has been made to investigate to identify the fast and luxuriantly growing halophytic herbs which are salt accumulators and to assess the feasibility of salt bioaccumulation. From the results it is concluded that among six species studied Suaeda maritima and Sesuvium portulacastrum exhibited greater accumulation of salts in their tissues as well as higher reduction of salts in the soil medium.  相似文献   
7.
AIM: To compare the effects of four stocking densities (5, 10, 15 or 20 birds per m2) on the performance, carcass characteristics and selected welfare indicators of broiler chickens. METHODS: A total of 756 day-old male broiler chicks were assigned as six replicates of 13, 25, 38 and 50 birds per pen, to stocking densities of 2,000, 1,000, 667 and 500 cm2 floor space per bird, respectively. The birds were housed in floor pens in an environmentally controlled room. Normal commercial diets were fed ad libitum and fresh water was freely available throughout the 5-week study period. Liveweights of birds and feed intake were recorded at weekly intervals. Data on carcass parameters and welfare indicators (moisture, gait scores, feather scores, breast and hip lesions, and foot pad and hock burns) were obtained on Day 35. Adrenal glands were removed at slaughter, weighed and examined histologically to determine the total proportion of cortical and medullary tissues. RESULTS: During the study, the birds at the lowest density grew faster (p<0.001-0.01) and consumed more (p<0.001- 0.01) feed than those at the other three stocking densities. The liveweight gains and feed intake of birds reared at densities of 10, 15 and 20 birds per m2 were similar (p=0.11-0.83 and p=0.17-0.57, respectively). Stocking density had no influence on the feed/weight gain, mortality or carcass characteristics. No breast or hip lesions were observed in carcasses from any of the groups. The weight and structure of the adrenal glands were similar across all groups although the staining of medullary tissue of birds was most intense in the highest stocking density group. As stocking density increased, so did moisture and gait score, hock and foot pad burn scores, and the feather score was adversely affected. CONCLUSIONS: The data showed that the relationship between stocking density and productivity traits was not linear in nature, in accordance with other studies. Under the conditions of the current study, the performance, mortality and carcass characteristics of broilers grown at densities of 10, 15 and 20 birds per m2 were similar. There were some welfare implications at high population densities as indicated by adverse effects on litter quality, gait scores and the incidence of hock and foot pad burns.  相似文献   
8.
1. The aim of the present study was to investigate the effect of an enzyme cocktail composed of xylanase, amylase and protease on the performance and nutrient utilisation of broiler starters fed on a maize-based diet. A maize/soy-based control diet was formulated to be marginal in apparent metabolisable energy (AME) and amino acids and this diet was fed without or with two concentrations (250 and 500 g/tonne) of the exogenous enzyme cocktail. 2. Growth performance was measured over a 21-d period after which ileal contents were collected for measurement of digestible energy, nitrogen and dry matter. Excreta were collected from d 17 to 20 post-hatch and used to determine the AME, and retention of nitrogen and dry matter. 3. Supplementation of the control diet with 250 and 500 g/tonne of the enzyme cocktail resulted in enhanced performance of the chicks (1.4 and 8.3%, respectively, for weight gain and 1.2 and 2.2%, respectively, for feed per gain), but the improvements were significant (P < 0.05) only at 500 g/tonne. 4. Addition of both 250 and 500 g/tonne improved AME, nitrogen-corrected AME and dry matter retention compared with the control though the improvements were greater with the higher dose. These effects were also reflected in the apparent ileal digestibility coefficients of dry matter, nitrogen and energy, with 500 g/tonne of the enzyme cocktail improving ileal digestible energy by 3.4%. 5. These results demonstrate that a cocktail of exogenous enzymes containing xylanase, amylase and protease is effective in improving the performance of broiler chicks fed on a maize/soybean-meal-based diet. However, these benefits may be dose-dependent and so an economic analysis involving ingredient and enzyme pricing and the relative performance and digestibility enhancements could allow the end user to select the most economical dose to maximise return on investment.  相似文献   
9.
Although chemical and some soil physical properties have been studied under different land uses of the Lesser Himalayas of India, very limited information is available on soil biochemical properties. Hence we investigated phosphorus (P) fractions [total P (TP), inorganic P (Pi), organic P (Po), available P, microbial biomass P (MBP)], enzyme activities [dehydrogenase, phosphatases, phytase], phosphate solubilizing bacteria (PSB) and fungi (PSF), and their correlations of acid soils (0–15 and 15–30 cm depths) under different land uses (viz, organic farming, maize–wheat, apple orchard, undisturbed oak forest and uncultivated land of the Indian Himalayas). All land use systems differed significantly for the P fractions, except TP. The highest values for TP, Pi, available P and MBP were found in soils under oak forest and lowest in uncultivated land. However, Po content was highest in apple orchard. The organic farming (organic manures field under garden pea-french bean cropping system for > 10 years) maintained highest activities of dehydrogenase, acid phosphatase and alkaline phosphatase. The highest phytase activity and highest numbers of PSB (99 × 103 g?1 soil) and PSF (30 × 103 g?1 soil) were observed in the rhizosphere soils of oak forest. Significant relationships between soil P fractions and enzyme activities, except alkaline phosphatase, were recorded in surface soil layer. PSB and PSF population were also correlated significantly with P fractions and enzyme activities. This would lead us to understand the level of degradation of P pools due to cultivation over forest system and the suitable management practices needed for soil quality restoration.  相似文献   
10.
编者按:在家禽养殖中,饲料是支撑家禽生长的最基本元素.除去营养需要外,高度加工处理的饲料从一开始着眼于提高家禽的生产性能,以达到效率最优化.  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