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11.
Stergiadis S Leifert C Seal CJ Eyre MD Nielsen JH Larsen MK Slots T Steinshamn H Butler G 《Journal of agricultural and food chemistry》2012,60(29):7270-7281
There is increasing concern that the intensification of dairy production reduces the concentrations of nutritionally desirable compounds in milk. This study therefore compared important quality parameters (protein and fatty acid profiles; α-tocopherol and carotenoid concentrations) in milk from four dairy systems with contrasting production intensities (in terms of feeding regimens and milking systems). The concentrations of several nutritionally desirable compounds (β-lactoglobulin, omega-3 fatty acids, omega-3/omega-6 ratio, conjugated linoleic acid c9t11, and/or carotenoids) decreased with increasing feeding intensity (organic outdoor ≥ conventional outdoor ≥ conventional indoors). Milking system intensification (use of robotic milking parlors) had a more limited effect on milk composition, but increased mastitis incidence. Multivariate analyses indicated that differences in milk quality were mainly linked to contrasting feeding regimens and that milking system and breed choice also contributed to differences in milk composition between production systems. 相似文献
12.
不同沼肥对油菜产量、品质及氮素利用效率的影响 总被引:6,自引:1,他引:6
利用温室盆栽试验研究了鸡粪沼肥(鸡粪沼渣、沼液)和牛粪沼肥(牛粪沼渣、沼液)对油菜产量、品质及氮素利用效率的影响。试验共设8个处理,分别为:不施肥(CK),鸡粪沼渣全部做底肥(JZ),鸡粪沼渣做底肥、沼液做追肥(JZ+JY),鸡粪沼液一半做底肥另一半做追肥(JY),牛粪沼渣全部做底肥(NZ),牛粪沼渣做底肥与沼液做追肥(NZ+NY),牛粪沼液一半做底肥另一半做追肥(NY),化肥一半做底肥另一半做追肥(HF),以上处理除空白外均按等氮量施用。研究结果表明,施用鸡粪沼肥比施用牛粪沼肥处理的油菜产量高,JZ、JZ+JY、JY3个处理油菜产量分别为13.8,14.9,14.8 g/盆,分别比牛粪沼肥相同处理(NZ、NZ+NY和NY)高40%,23%和11%。施用鸡粪沼肥处理油菜的硝酸盐含量要比相应施用牛粪沼肥的高,但在Vc含量上差异不显著;鸡粪沼肥氮素利用效率显著高于牛粪沼肥,这可能和鸡粪沼肥比牛粪沼肥速效养分含量高、养分释放快有关系。 相似文献
13.
Vibrio anguillarum , an opportunistic fish pathogen, is the main species responsible for vibriosis, a disease that affects feral and farmed fish and shellfish, and causes considerable economic losses in marine aquaculture. In this study, we used polymerase chain reaction (PCR) to detect V. anguillarum . PCR specificity was evaluated by amplifying the rpoS gene, a general stress regulator, in six strains of V. anguillarum and 36 other bacterial species. PCR amplified a species-specific fragment (689 bp) from V. anguillarum . Furthermore, the PCR assay was sensitive enough to detect rpoS expression from 3 pg of genomic DNA , or from six colony-forming units (CFU) mL−1 of cultured V. anguillarum . However, the assay was less sensitive when genomic DNA from the infected flounder and prawn was used (limit of detection, 50 ng and 10 ng g−1 tissue, respectively). These data demonstrate that PCR amplification of the rpoS gene is a sensitive and species-specific method to detect V. anguillarum in practical situations. 相似文献
14.
鉴定了测定土壤和粘土矿物阳离子交换量(CEC)的4种方法:(1)常规NH4-Na交换法;(2)亚甲基蓝与亚甲基蓝酸容量法;(3)焦磷酸钠法:(4)亚甲基蓝滤纸点测滴定法。供试样品为采自台湾农田的18份表层(0-15cm)土样,并以粘放物学分的4份样品为参照。试验结果表明,在亚甲基蓝溶液的絮凝,平衡时间和浓度都合适的条件下,能用亚甲基蓝吸附法测定土壤和粘土矿物的阳离子代换量。与常规NH4-Na交换法 相似文献
15.
Weber HA Zart MK Hodges AE Molloy HM O'Brien BM Moody LA Clark AP Harris RK Overstreet JD Smith CS 《Journal of agricultural and food chemistry》2003,51(25):7352-7358
The characterization of herbal materials is a significant challenge to analytical chemists. Goldenseal (Hydrastis canadensis L.), which has been chosen for toxicity evaluation by NIEHS, is among the top 15 herbal supplements currently on the market and contains a complex mixture of indigenous components ranging from carbohydrates and amino acids to isoquinoline alkaloids. One key component of herbal supplement production is botanical authentication, which is also recommended prior to initiation of efficacy or toxicological studies. To evaluate material available to consumers, goldenseal root powder was obtained from three commercial suppliers and a strategy was developed for characterization and comparison that included Soxhlet extraction, HPLC, GC-MS, and LC-MS analyses. HPLC was used to determine the weight percentages of the goldenseal alkaloids berberine, hydrastine, and canadine in the various extract residues. Palmatine, an isoquinoline alkaloid native to Coptis spp. and other common goldenseal adulterants, was also quantitated using HPLC. GC-MS was used to identify non-alkaloid constituents in goldenseal root powder, whereas LC-MS was used to identify alkaloid components. After review of the characterization data, it was determined that alkaloid content was the best biomarker for goldenseal. A 20-min ambient extraction method for the determination of alkaloid content was also developed and used to analyze the commercial material. All three lots of purchased material contained goldenseal alkaloids hydrastinine, berberastine, tetrahydroberberastine, canadaline, berberine, hydrastine, and canadine. Material from a single supplier also contained palmatine, coptisine, and jatrorrhizine, thus indicating that the material was not pure goldenseal. Comparative data for three commercial sources of goldenseal root powder are presented. 相似文献
16.
Utilization of the major corn (Zea mays) reserve materials (free saccharides, starch, triglycerides, and zein) was monitored during infection of detached kernels by Aspergillus flavus (A. flavus) over a 12-day period. Inoculated whole kernels were compared to noninoculated kernels. Concentrations of sucrose and raffinose in inoculated seed decreased to nearly zero at 6 days, whereas concentrations of these saccharides in noninoculated seed dropped at a considerably slower rate, and significant levels remained at the end of the incubation period. Triglyceride concentrations remained unchanged in the noninoculated seed but dropped continuously after 2 days in the inoculated seed. Starch and zein concentrations did not change during the 12-day incubation period. Aflatoxin B1 was first detected after 2 days and increased to about 20 microg/g (20,000 ppb) after 12 days. Very low aflatoxin concentrations were detected in the noninoculated seed. Significant concentrations of erythritol, arabitol, and mannitol were produced during infection, with peak concentrations occurring at 8 days. Whole seed and germ tissue appeared to support good fungal growth and aflatoxin production, whereas ground tissues and endosperm did not. A. flavus preferentially utilized saccharides as initial carbon substrates followed by triglycerides. When invading nonwounded corn kernels, the fungus selectively targets the germ tissue where these materials are localized in the highest concentrations. 相似文献
17.
18.
Fernandez-Orozco R Frias J Muñoz R Zielinski H Piskula MK Kozlowska H Vidal-Valverde C 《Journal of agricultural and food chemistry》2007,55(22):8972-8979
The effect of fermentation on the antioxidant compounds [vitamins C and E, total phenolic compounds (TPC), and reduced glutathione (GSH)], and antioxidant capacity [superoxide anion scavenging activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), inhibition of phosphatidylcholine (PC) peroxidation, and Trolox equivalent antioxidant capacity (TEAC)] of soybean (Glycine max cv. Merit) was studied. Fermentation was carried out in solid state in cracked seeds inoculated with Aspergillus oryzae, Rhizopus oryzae, Bacillus subtilis, and Lactobacillus plantarum and in liquid state either in cracked seeds or milled soybean flours fermented naturally by only the microorganisms present in the seeds or by inoculation with L. plantarum. Vitamin C was not detected in the studied samples. Fermentation caused a decrease in vitamin E activity, except when cracked seed was fermented with A. oryzae, R. oryzae, or B. subtilis that increased 31, 30, and 89%, respectively. Fermentation produced an increase in TPC content and did not affect or reduce the GSH content. Fermentation decreased SOD-like activity drastically, while PRTC increased except when it was carried out naturally in cracked seed. TEAC values rose sharply when soybeans were fermented with B. subtilis. Processed soybean extracts inhibited PC peroxidation in comparison with the control assay. On the basis of the results obtained, the relative contributions of vitamin E, TPC, and GSH to antioxidant capacity were calculated and results showed a very high TPC contribution and a low contribution of GSH and vitamin E activity. Optimum results for functional soybean flours were achieved when fermentation was carried out with B. subtilis inoculum. 相似文献
19.
文章分析了鹰潭市退耕还林在实施过程中存在的地块分散、管理难度大、检查层次多、配套金费不落实等主要问题,并针对这些问题提出了相应的完善对策。 相似文献
20.