Niacin,thiamin, iron and protein status of humans as affected by the consumption of tea (Camellia sinensis) infusions

The objective of the project was to determine the effects of tea (Camellia sinensis) leaf beverage consumption on the apparent utilization of niacin, thiamin, and protein in human subjects. During two randomly arranged experimental periods of 14 days each, 10 adult female human subjects were fed a constant (same foods each day), measured, laboratory-controlled diet. Tea was fed during one period while no tea was allowed during the other period. A dehydrated black tea infusion product (instant tea, 8 g/subject/day/dry weight basis) was used which subjects were allowed to dilute in water. Subjects made complete collections of urine and stools. Fasting blood samples were drawn at the end of each experimental period. No effects on protein status were demonstrated. Urinary thiamin losses were depressed with the use of tea but niacin losses were increased. Blood serum concentrations of thiamin diphosphate also were depressed during the tea drinking period as compared to values during the non-tea period. No significant effect on blood serum levels of nicotinaminde or N-methylnicotinamine were found but values tended to be lower during the tea than the non-tea period. These results suggest that tea consumption inhibits the utilization of thiamin. However, niacin availability was unaffected by tea drinking. Because of the decreased availability of thiamin, the need for niacin was depressed which caused a greater than expected urinary loss of this vitamin.Published as University of Nebraska Journal Articles Series No. 9496. Supported by University of Nebraska Agricultural Research Division Project 91-031 and U.S.D.A. C.S.R.S. Regional Project W-143.     

缩合单宁功能性研究探讨

缩合单宁作为一种植物次生代谢物，其含量的多少直接影响到牧草的营养品质和动物的适口性。本文从缩合单宁的结构入手，着重综述了缩合单宁的功能，探讨了其在生产应用中对动植物的影响，以期为牧草选育和畜牧业生产提供一些有益的参考。     

毛白杨二氢黄酮醇合酶基因PtDFR1的克隆与功能验证

以RT-PCR的方法获得毛白杨(Populus tomentosa Carr.)二氢黄酮醇合酶基因(Dihydroflavonol 4-reductase)DFR,命名为PtDFR1,完整的ORF编码336个氨基酸,含有DFR蛋白特征性序列:NADP结合域和特异性底物识别域。序列比对发现,毛白杨PtDFR1蛋白与其他已知物种DFR有较高同源性,特别是与欧洲颤杨(Populus tremuloides)和葡萄(Vitis vinifera)以及苹果(Malus x domestica)氨基酸序列同源性最高,分别达到89.9%,86.4%和85.1%。荧光定量PCR检测基因组织特异性表达发现,该基因在根中表达量最高,其次为叶柄,而在叶片中表达丰度最低。根癌农杆菌介导PtDFR1在毛白杨中超量表达,检测转基因株系中花青素和缩合单宁的含量发现,与野生型相比,转基因植株中缩合单宁产量提高2～3倍,而花青素含量无显著变化,表明PtDFR1可能主要在缩合单宁合成途径中发挥作用。     

采收时间对玫瑰茄萼片产量及营养成分的影响

为明确玫瑰茄最佳采收时间,以玫瑰茄种质M3和M5为试验材料,对不同采收时间玫瑰茄的萼片产量和原花青素、单宁等营养成分含量进行分析。结果表明,随着采收时间推迟,2份种质的萼片产量和营养成分含量均呈先增加后减少的趋势。M3的鲜果重、鲜萼片重均在开花后21 d达到最大值,分别为12.82 g和7.75 g,干萼片重在开花后28 d达到最大值,为0.98 g;M5的鲜果重在开花后21 d达到最大值,为6.97 g,鲜萼片重、干萼片重均在开花后28 d达到最大值,分别为3.90 g和0.47 g,以采收花萼为目的时,适宜采收期为开花后21~28 d。M3萼片的原花青素含量在开花后35 d时最高,达2 180.00 mg·kg^-1,M5在开花后21 d时最高,达573.50 mg·kg^-1,以提取原花青素为目的采收时,M3和M5的适宜采收期分别为开花后35 d和开花后21 d。M3的单宁含量在开花后28~35 d时最高,达2.30 g·kg^-1, M5在开花后42 d时最高,达1.38 g·kg^-1,以提取单宁为目的采收时,M3和M5的适宜采收期分别为开花后28~35 d和开花后42 d。综上,玫瑰茄的适宜采收时间为开花后一个月左右(28~35 d)。本研究可为玫瑰茄合理采收提供参考依据。     

棕色棉发育期儿茶素的HPLC分析

以棕色棉和白色棉为材料,利用HPLC法测定发育期种皮与纤维中儿茶素的组分与变化规律。结果表明:棉铃发育期,深棕ANL-1和泗棉3号种皮中有儿茶素单体EGC、C、EC,纤维中有GC、C。深棕ANL-1种皮中主要组分C的含量高于泗棉3号,且在28~35DPA阶段迅速下降。深棕ANL-1纤维中GC和C的含量均表现出先升后降的趋势。泗棉3号发育期纤维中各儿茶素组分含量水平非常低。初步推断在纤维伸长期,儿茶素等棕色素前体不断合成并积累,并在次生壁沉积期被逐渐氧化消耗而形成有色的棕色素。     

柿果实单宁细胞特征与总酚和缩合单宁含量的关系

In this study,51 accessions of mature persimmon fruits were used as materials to investigate the correlation between characteristics of tannin cells,and total phenolics and condensed tannins contents. ...     

Effects of inclusion of whole-crop pea silages differing in their tannin content on the performance of dairy cows fed high or low protein concentrates

The effect of including high or low tannin forage peas as an alternative to soyabean meal on performance and N efficiency was investigated using 18 dairy cows in two Latin square design studies. Two varieties of forage pea; Racer (coloured flowers; high tannin) and Croma (white flowers; low tannin), were ensiled 12 weeks post sowing. The in situ degradability characteristics of the pea silages were determined using 4 cannulated sheep. The low tannin forage had a higher soluble N (a) fraction and a greater extent of degradation (a + b), resulting in a greater amount of N being predicted to be released in the rumen than the high tannin forage. In experiment 1, cows were fed one of three treatments in each of 3 periods of 28 d duration in a Latin square design; grass silage/whole-crop wheat (0.50:0.50, DM basis) and 8 kg/d of a high protein concentrate (GWH); grass silage/whole-crop wheat/high tannin forage pea silage (0.25:0.25:0.50 respectively, DM basis) and 8 kg/d of a high protein concentrate (HTH) or 8 kg/d of a low protein supplement (HTL). The inclusion of forage peas increased (P < 0.05) DM intake by 1.2 kg DM/d, but there was no effect of dietary treatment on milk yield (average of 23.0 kg/d), composition or live weight change. The efficiency of use of dietary N (N output in milk/N intake) was highest (P < 0.001) in cows when fed GWH (0.289) and lowest in HTH (0.234). In experiment 2, cows were fed one of three treatments in each of 3 periods of 28 d duration in a Latin square design; grass silage/whole-crop wheat (0.50:0.50, DM basis) and 8 kg/d of a high protein concentrate (GWH); grass silage/whole-crop wheat/low tannin forage pea silage (0.25:0.25:0.5 respectively, DM basis) and 8 kg/d of a high protein concentrate (LTH) or 8 kg/d of a low protein concentrate (LTL). Compared with GWH, the inclusion of forage peas increased (P < 0.05) DM intake by 2.0 kg/d, but there was no effect of dietary treatment on milk yield (average of 24.5 kg/d). Milk fat content was highest (P < 0.05) in cows when fed LTL (45.7 g/kg) and lowest in LTH (41.9 g/kg), but there was no effect (P > 0.05) of treatment on daily fat yield or any other milk component. The efficiency of dietary N use was highest (P < 0.001) in cows when fed GWH (0.300) and lowest in LTH (0.234). It is concluded that either high or low tannin forage pea silages can replace approximately 1.1 kg/d of soyabean meal in the diet of mid-late lactation dairy cows without affecting animal performance, but N efficiency for milk production is decreased.     

Influence of dietary condensed tannins from sericea lespedeza on bacterial loads in gastrointestinal tracts of meat goats

This research assessed the potential use of a low input forage containing a high amount of condensed tannins (CT) to reduce foodborne pathogens prior to slaughter of meat goats. In a completely randomized design, twenty Kiko × Spanish intact male kids (BW = 19.2 ± 0.74 kg) were fed ground sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours) G. Don; 2 pens], a high-CT legume, or bermudagrass hay [BG; Cynodon dactyon (L.) Pers.; 2 pens], at 75% of daily intake with a corn-based supplement (25% of intake) for 14 weeks (n = 10 goats/treatment). At the end of the feeding trial, the animals were slaughtered using standard procedures. Immediately after evisceration, rumen and rectal samples were collected to assess bacterial loads and volatile fatty acids in the rumen. Concentrations of rumen volatile fatty acids were significantly different between dietary treatments. Goats fed SL hay had higher (P < 0.05) contents of butyric (8.66 vs 7.16 mM), isobutyric (1.94 vs 1.44 mM), isovaleric (3.03 vs 2.13 mM), and valeric (1.43 vs 1.07 mM) acids than those fed BG hay; however, the content of acetic acid (78.6 vs 64.4 mM) was higher (P < 0.05) in the BG-fed groups than in SL-fed groups. Escherichia coli (2.33 vs 1.13 log₁₀ CFU/g) counts of rumen contents were higher (P < 0.05) in the SL-fed group compared with the BG-fed group. However, E. coli counts in feces were not different (P > 0.05) between dietary treatments. The high-CT influenced (P < 0.05) total plate counts in the feces; and the total plate counts in feces of SL- and BG-fed goats were 4.95 and 6.57 log₁₀ CFU/g, respectively. The results indicated that high CT in the diet might influence rumen volatile fatty acid composition, but might not reduce the bacterial loads in gastrointestinal tracts of meat goats.     

The effect of polyethylene glycol on browsing behaviour of beef cattle in a tanniferous shrubby Mediterranean range

The aim of the present study was to determine the effect of polyethylene glycol (PEG) supplementation on grazing behaviour of beef cattle and on utilization of the woody components of a Mediterranean shrubland. Two experiments were conducted on two different sites in Northern Israel, Ramat Hanadiv (RH) and Hatal. On each site, the study area was divided into two paddocks, in one cattle were supplemented with 50 g PEG day^− 1 per cow, while the other served as a control, with no PEG supplementation. In RH site the cows had free access to Prolix and in Hatal to poultry litter, both serving as a nitrogen supplement during the experiment. In the RH site, the consumption of Pistacia lentiscus, a shrub whose leaves contain high concentration of tannins, was found higher (P = 0.001) in the PEG group diet than in the control group. In Hatal site PEG increased foraging time by 18%, daily foraging distance by 15% and reduced the use of supplementary feed (poultry litter) by 20%. However, PEG did not affect the average cow body weight or water consumption on either site. It is concluded that PEG influences grazing behaviour of beef cattle on shrubby rangeland and increases the use of woody species with high tannin concentrations.     

Use of plants in novel approaches for control of gastrointestinal helminths in livestock with emphasis on small ruminants

Helminth infections are a major cause for reduced productivity in livestock, particularly those owned by the poor worldwide. Phytomedicine has been used for eons by farmers and traditional healers to treat parasitism and improve performance of livestock, and many modern commercial medicines are derived from plants. However, scientific evidence on the anti-parasitic efficacy of most plant products is limited, regardless of their wide ethnoveterinary usage. Scientific validation of the anti-parasitic effects and possible side-effects of plant products in ruminants is necessary prior to their adoption as a novel method for parasite control. A variety of methods has been explored to validate the anthelmintic properties of such plant remedies, both in vivo and in vitro. In vitro assays are useful as pre-screens of activity and are mainly performed with the free-living rather than parasitic stages of nematodes. Concentrations of potentially active substances used in vitro do not always correspond to in vivo bioavailability. Therefore, in vitro assays should always be accompanied by in vivo studies when used to validate the anthelmintic properties of plant remedies. In vivo controlled studies have shown that plant remedies have in most instances resulted in reductions in the level of parasitism much lower than those observed with anthelmintic drugs. Whether it is necessary or not to achieve very high efficacy in order for plant remedies to have a role in the control of parasitism depends on the determination of biologically important levels of reduction of parasitism and it will be required prior to the wide-scale use of plant products for parasite control. Similarly, standardisation of validation studies in reference to the numbers of animals required for in vivo studies to measure direct anthelmintic effects of a plant needs to be established. Although in many cases the active compounds in the herbal remedies have not been fully identified, plant enzymes, such as cysteine proteinases, or secondary metabolites, such as alkaloids, glycosides and tannins have shown dose-dependent anti-parasitic properties. However, as some of the active compounds may also have anti-nutritional effects, such as reduced food intake and performance, it is essential to validate the anti-parasitic effects of plant products in relation to their potential anti-nutritional and other side effects. A concerted effort on isolation, development, and validation of the effects of these herbal remedies will have to be undertaken before their wider acceptance.