基因型对红三叶异黄酮含量的影响

采用高效液相色谱法,对4个不同红三叶品种的异黄酮含量进行了分析,发现基因型对红三叶的异黄酮总含量影响显著,4个供试材料的异黄酮总含量为:新品系R-1>瑞德>岷山>多丽.基因型对红三叶各异黄酮单体含量变化影响不同,对大豆黄素含量的变化影响最大,对刺芒柄花素含量的变化影响最小.红三叶积累刺芒柄花素的能力最高,其次是鹰嘴豆芽...     

Effects of high-sugar ryegrass silage and mixtures with red clover silage on ruminant digestion. 1. In vitro and in vivo studies of nitrogen utilization

Two experiments were carried out to determine the effects of feeding grass silages differing in their water-soluble carbohydrate content, with or without red clover silage, on the efficiency of nutrient use. High-sugar grass, control grass, and red clover were ensiled in laboratory silos for use in an in vitro experiment (Exp. 1). For an in vivo experiment (Exp. 2), the same forage types were baled and ensiled. All silages were well preserved; within experiments the grass silages had similar composition, except for greater (P < 0.05) water-soluble carbohydrate concentrations in the high-sugar than the control grass silage. In Exp. 1, high-sugar grass, control grass, and red clover silages were fed alone or as mixtures (30:70, 50:50, or 70:30 on a DM basis, respectively) of each grass with the red clover silage to a simulated rumen culture system. There were no significant differences in microbial N flow or efficiency of microbial protein synthesis between individual forages. However, the corresponding values for the 70:30 ratio of high-sugar grass:red clover silage were greater (P < 0.05) than for the red clover silage. The value for the efficiency of N use (g of microbial N/g of feed N) was greater (0.86; P < 0.05) for high-sugar grass silage than the control grass silage. In addition, the high-sugar grass:red clover silage mixtures all gave greater (P < 0.05) values for the efficiency of N use than red clover silage alone; this difference was not achieved with the control grass mixture. Experiment 2 was an incomplete Latin square design conducted with 6 Here-ford x Friesian steers (163 +/- 5.9 kg of BW) with rumen and duodenal cannulas fed the following 5 silage diets: high-sugar grass silage; control grass silage; high-sugar grass and red clover silage (50:50 DM basis); control grass and red clover silage (50:50 DM basis); and red clover silage. Rumen NH3-N concentration was lowest (P < 0.05) with the high-sugar grass silage. Microbial N flows to the duodenum and efficiency of microbial protein synthesis were greater (P < 0.05) for steers fed the high-sugar grass silage than for control grass and red clover silages, and mixing red clover with grass silages increased (P < 0.05) these values compared with red clover silage alone. In both experiments, the efficiency of incorporation of silage N into microbial N was more than 20% greater (P < 0.05) for high-sugar grass than for control grass silage. These data suggest that grass silage with high-sugar content provides a forage-based strategy for balancing N and energy supply and improving the efficiency of use of grass silage N in the rumen.     

Effects of high-sugar ryegrass silage and mixtures with red clover silage on ruminant digestion. 2. Lipids

The experiment investigated the digestion of lipids from different forage silages in beef steers. Six Hereford x Friesian steers prepared with rumen and duodenal cannulas were given ad libitum access to a high-sugar grass silage, control grass silage, red clover silage, or mixtures of the red clover and each of the grass silages (50:50, DM basis). The experiment was conducted as an incomplete 5 x 5 Latin square, with an additional randomly repeated sequence. Total fatty acid and C18:3n-3 concentrations were greater (P < 0.05) for the high-sugar grass silage than the control grass silage or the red clover silage. Dry matter and total fatty acid intake were less (P < 0.05) for steers fed the control grass silage than for steers fed the other diets. Duodenal flow of C18:3n-3 was greater (P < 0.05), and flows of C18:0 and total C18:1 trans were less (P < 0.05), for the red clover silage compared with the 2 grass silage diets, with the mixtures intermediate. These results were supported by a reduction (P < 0.05) in biohydrogenation of C18:3n-3 for the red clover silage, with the mixtures again being intermediate. Flows of total branched- and odd-chain fatty acids were greater (P < 0.05) for the high-sugar grass silage diet, possibly as a result of greater microbial flow, because these fatty acids are associated with bacterial lipid. Duodenal flows of the chlorophyll metabolite, phytanic acid, were greater (P < 0.05) for animals fed the high-sugar grass silage treatments compared with the other treatments. These results confirm the potential for modifying the fatty acid composition of ruminant products by feeding red clover silage.     

Combined action of plant estrogens, F-2 toxin and natural estrogens

The investigation concerns the interaction of plant estrogens, F-2 toxin, and natural estrogen (estradiol-benzoate) as causative factors of eostrogenic changes. Plant estrogens and F-2 toxin were applicated at three and estradiol-benzoate at two dosage levels. The estrogenic effect was studied by bioassay on immature rats taking uterine weight, uterine liquid and vaginal opening as criteria. When uterine weight is taken as a criterion, plant estrogens and F-2 toxin, no matter if they are administered alone or together, regularly increase the effect of estradiol-benzoate, but when uterine fluid is taken as a criterion they always decrease the effect of estradiol-benzoate. According to the present results it seems obvious, that the mode of action of estrogenic substances occurring in plants considerably differ from that of natural estrogens. Thus the mechanisms which cause disturbances may be different from those of natural estrogens.     

Effects of Oestrogenic Silage on Some Clinical and Endocrinological Parameters in Ovariectomized Heifers

Nwannenna A.I., A. Madej, T.J-O. Lundh and G. Fredriksson: Effects of oestrogenic silage on some clinical and endocrinological parameters in ovariectomized heifers. Acta vet scand. 1994, 35, 173-183.–The influence of phytoestrogens was studied in 3 ovariectomized Swedish Friesian heifers fed 20 kg of 100% red clover silage per heifer/day for 14 days. Behaviour, reproductive organs and pituitary response to exogenous gonadotropin-releasing hormone (GnRH) injections were monitored. Clinical effects like oedema and mucous discharge in the vulva, presence of milky fluid in the mammae and increases in teat size and the cross-sectional distance of the uterus were observed in heifers fed red clover silage. Fluid accumulation in the uterus, visualized by means of ultrasonography, had still not disappeared 30 days after the red clover silage had been completely withdrawn. Red clover silage appeared to reduce the magnitude and duration of the pituitary response to GnRH injections.     

Monitoring of vitamin E status of dry,early and mid‐late lactating organic dairy cows fed conserved roughages during the indoor period and factors influencing forage vitamin E levels

Analysis of blood plasma of 60 cows selected on six Flemish organic dairy farms revealed that on average 12% of all samples and on one farm up to 28% of the organic cows showed plasma vitamin E concentrations less than 3.0 μg/ml, which is considered the minimum level to avoid health risks due to vitamin E shortages. Furthermore, this study showed early lactating and dry cows to be more at risk in relation to animals in mid‐late lactation. In European organic farming, vitamin supplements are only allowed if granted by the local authority to satisfy daily requirements. Therefore, the vitamin E content of the feedstuffs used on the farms was determined. Grass clover silage (GCS) and mixed silage had significantly more vitamin E than hay, maize or grain (p < 0.05) [mean (SD): 52 (35), 29 (20), 4.5 (1.7), 4.9 (4.4) and 7.1 (3.8) mg/kg DM, respectively]. Apparently, variation in the vitamin E content in the silage samples was huge. Hence, the vitamin E content of ryegrass, white and red clover was determined in a second lab scale experiment and the effects of wilting, DM content and supplementation of ensiling additives were investigated. Fresh ryegrass had a higher vitamin E content than white and red clover (p < 0.05) [156 (11.3), 49.3 (0.67) and 74.3 (5.73) μg/g DM, respectively]. These differences remained after the wilting or ensiling. Supplementation of formic acid or lactic acid bacteria at ensiling had no significant effect on the vitamin E content. Overall, it can be concluded that GCS is the most important source of vitamin E in organic dairy farming. A legal possibility for case‐related supplementation should be retained in organic dairy farming as approximately 18% of all dry and early lactating cows were at risk of vitamin E shortage.     

Phytoestrogen Content of Birdsfoot Trefoil and Red Clover: Effects of Growth Stage and Ensiling Method

The phytoestrogen content of birdsfoot trefoil (Lotus corniculatus L.) and red clover (Trifolium pratense L.) was determined. In addition, the effects of growth stage, wilting and ensiling additives on content were studied. Birdsfoot trefoil raw material and silage contained only traces of phytoestrogens. In red clover raw material and silage, the phytoestrogen content varied from 0.8% to 1.1% of dry matter. Content was affected by growth stage of the plant and wilting. Formononetin concentration decreased as the plant matured from budding to flowering stage, and wilting from 25% to 40% of dry matter content decreased genistein and biochanin A content. The phytoestrogen content of red clover silage was 18% higher than that of raw material. Silage additives also affected the content. Silage ensiled with an additive containing Lactobacillus plantarum bacterial inoculate had higher concentrations of genistein and biochanin A than silage made with formic acid.     

添加剂对白三叶青贮的影响

为探讨不同添加剂对白三叶（Trifolium repens）青贮的影响,以营养生长期白三叶为原料,分别设计对照、添加甲酸（6 mL/kg）、蔗糖（2%）处理,袋装密封青贮360 d后取样分析。结果表明,添加甲酸或蔗糖都能显著改善白三叶青贮饲料的发酵品质,极显著降低青贮饲料的pH值、乙酸和氨态氮含量（P<0.01）,极显著增加乳酸含量（P<0.01）。添加甲酸或蔗糖显著提高白三叶青贮饲料的干物质保存率（P<0.05）,显著提高ADF含量（P<0.05）。青贮之后,硝酸盐含量下降。     

Comparison of the German and the Dutch protein evaluation system in dairy nutrition when applied to different rations with graded protein levels.

The Dutch (DVE) and the German (nXP) protein evaluation system were compared using data from four specially designed dairy feeding trials. The criterion for comparison was the divergence between predicted and observed milk protein yield with the respective protein evaluation system. Different forages were fed in each series of experiments, namely red clover/meadow grass, meadow grass, grass silage and maize silage, respectively. To achieve a diversified database, protein was supplied at 2 or 3 different levels in each experiment. Across all measured data, the two protein evaluation systems resulted sometimes in considerable differences between predicted and observed protein yield. The observed yield was overestimated by 223 g per cow and day with the DVE system and by 144 g per cow and day with the nXP system. The magnitude of the bias varied depending on the type of ration fed. In experiments with fresh forage the difference between predicted and observed milk protein yield was far greater with the DVE system than that calculated with the nXP system (difference 322 g vs. 162 g), whereas after feeding grass silage the differences between the two protein evaluation systems were small (194 g vs. 182 g). In experiments with maize silage the predicted value was close to the observed value both with the DVE and the nXP system (difference 48 g vs. 80 g).     

红三叶异黄酮对肉鸡血液几种内源性激素水平的影响

本试验旨在研究饲粮中添加红三叶异黄酮对肉鸡血液几种内源性激素水平的影响。选取1日龄雄性爱拔益加肉仔鸡240羽,随机分为4组(每组4个重复,每个重复15只),分别饲喂在基础饲粮中添加0(对照组)、10(试验Ⅰ组)、20(试验Ⅱ组)、30 mg/kg(试验Ⅲ组)红三叶异黄酮的试验饲粮。试验持续7周。结果表明:试验Ⅰ组和试验Ⅱ组的平均日增重显著或极显著高于对照组和试验Ⅲ组(P<0.05或P<0.01)。各试验组料重比均低于对照组,但差异不显著(P>0.05)。血清生长激素(GH)水平,试验Ⅱ组在21、35和49日龄均显著或极显著高于对照组(P<0.05或P<0.01),试验Ⅰ组在49日龄、试验Ⅲ组在21日龄显著或极显著高于对照组(P<0.05或P<0.01);血清类胰岛素生长因子Ⅰ(IGF-Ⅰ)水平,各试验组在21日龄均显著高于对照组(P<0.05),试验Ⅱ组在49日龄显著高于对照组和其他试验组(P<0.05);血清三碘甲腺原氨酸(T3)水平,试验Ⅰ组在35和49日龄、试验Ⅱ组在49日龄均显著或极显著高于对照组(P<0.05或P<0.01);血清四碘甲腺原氨酸(T4)水平,试验Ⅰ组和试验Ⅲ组在35日龄显著低于对照组(P<0.05);血清T3/T4,各试验组在21、35和49日龄均高于对照组,并且在35和49日龄试验Ⅰ组与对照组达到显著水平(P<0.05);血清睾酮(TESTO)水平,各组在21、35和49日龄均无显著差异(P>0.05)。由此得出,红三叶异黄酮可通过调节体内GH、IGF-Ⅰ、T3和T4水平来影响肉鸡的生长性能,饲粮中添加20 mg/kg时促生长效果较好。     

红三叶个体水平异黄酮含量的差异及其形态特征和草产量比较研究

为探索选育高异黄酮含量红三叶(Trifolium pratense L.)新种质材料的可行途径，本研究测定和林格尔县实验地中300株红三叶地上部分的异黄酮含量，采用K-means聚类分析方法，将不同异黄酮含量红三叶聚类为4个类群(T1～T4),同时对4个红三叶类群进行形态特征进行观测，以及对各农艺性状和产量指标进行测定。结果表明：300株红三叶异黄酮含量介于15.65～34.16 mg·g^-1,平均含量为24.88 mg·g^-1。不同异黄酮含量的红三叶类群在形态特征、农艺性状、草产量等方面具有显著性差异，其中高异黄酮含量红三叶群体占300株的18.67%,平均含量为29.61 mg·g^-1,具有绝对株高和自然株高差值大于15 cm(平卧型)和叶片面积小于350 mm²的形态特征；同时绝对株高、草产量也显著更高(P<0.05)。本研究为红三叶高产优质栽培和品种选育奠定了基础。     

多菌灵在果园白三叶青贮中的降解及其对微生物群落的影响

为了解白三叶青贮后不同浓度多菌灵农药的降解情况和果园喷施多菌灵对白三叶青贮过程中细菌多样性的影响,扩大具有农药残留的果园覆盖植物利用途径,在喷施不同浓度［2.0 （RU^-）,2.5 （RU）,3.0 g·L^-1 （RU⁺）］的多菌灵后进行白三叶青贮,以喷水为对照,发酵60 d。采用Miseq高通量测序技术,分别在青贮开始前、青贮第3和60天取样,对白三叶中细菌群落多样性进行研究。结果表明,青贮后多菌灵降解率达到59.6%以上,喷施量越高,降解率越高;多菌灵处理显著（P<0.05）增加了白三叶青贮发酵的乳酸、乙酸、丙酸含量,乳酸在多菌灵RU^-、RU、RU⁺浓度下分别增加了47.55%、63.24%、71.08%,乙酸分别增加了24.49%、44.90%、46.94%,丙酸分别增加了66.67%、187.50%、250.00%,有利于白三叶青贮饲料营养成分的保留;多菌灵喷施显著（P<0.05）改变了白三叶青贮菌群群落构成,增加了青贮的菌群丰度、多样性;多菌灵处理中乳球菌属、魏斯氏菌属、泛菌属、Rosenbergiella、假单胞菌属、寡养单胞菌属、肠杆菌属、芽孢杆菌属菌群丰度增加,不利于青贮发酵,但随着青贮时间的推移,寡养单胞菌属、肠杆菌属、芽孢杆菌属等菌群丰度减少。喷施多菌灵后有利于青贮发酵微生物菌群的丰度增加,对青贮发酵有害菌、多菌灵降解菌群丰度及青贮微生物多样性产生影响,青贮后多菌灵残留高于欧洲食品安全局规定的作物类动物饲料中农药最大残留量,达不到饲用标准。研究结果可为具有农药残留的白三叶青贮饲料的饲用安全性和果园覆盖植物资源的开发利用提供理论依据。     

6个商品添加剂对两个刈割茬次紫花苜蓿裹包青贮品质的影响

试验采用完全随机区组试验设计,以2个刈割茬次的甘农3号(Gannong No.3)紫花苜蓿为原料,分别添加青贮添加剂露保美NC、宜生贮宝、亚芯、乳酸菌发酵剂YM3和YM7、河北沧州乳酸菌进行裹包青贮,以不加添加剂为对照,45d后进行青贮指标测定、数据分析和灰色关联度分析,以研究添加剂对不同刈割茬次紫花苜蓿裹包青贮发酵品质的影响。结果表明:6种添加剂均能改善紫花苜蓿裹包青贮品质,且添加剂处理组优于对照组,其中,亚芯处理组pH最低,乳酸含量多,无丁酸(BA)生成,氨态氮含量最少,可溶性碳水化合物(WSC)消耗最低,发酵品质最好。且第2茬刈割的青贮品质优于第1茬。     

Effect of supplementation of fresh and ensiled clovers to ryegrass on nitrogen loss and methane emission of dairy cows

Two experiments were carried out to compare white clover with red clover as supplementation to ryegrass, in ensiled and fresh form, for differences in nitrogen loss and methane emission by dairy cows. In experiment 1, fresh ryegrass was mixed with fresh white (WF) or red clover (RF) (60/40 on dry matter basis). Experiment 2 involved similar mixed diets in ensiled form (WS and RS, respectively), and two ryegrass silage diets, without (GS) or with supplementary maize gluten meal (600 g protein/kg DM; GS+). Barley was supplemented to meet the calculated requirements for milk production. The type of clover did not affect crude protein (CP) intake in experiment 1. In experiment 2, the highest CP intakes were observed for cows on the GS+ diet (P < 0.05), followed by the WS and RS diet, compared to the GS diet. Within experiments, no treatment effects occurred for intake of digestible organic matter, milk and milk protein yield, while milk urea and urine N excretion mostly reflected the differences in CP intake in experiment 2. The highest absolute N excretions (P < 0.001) occurred with the GS+ diet, compared to the other diets. Per unit of N intake, a tendency for highest urine N losses with GS+ was still noticeable. The slurry characteristics were not affected by clover type during storage in experiment 1. In experiment 2, initial treatment differences in ammonia-N levels (P < 0.01) in the slurry were still observed after 8 weeks of storage. Clover supplementation, but not clover type, slightly enhanced gaseous N losses per cow per day in relation to GS, but not as much as GS+ (+53%). Gaseous N losses relative to milk N yield were slightly lower (P < 0.1) with fresh red clover compared to white clover, a trend not apparent in experiment 2 with silages where levels were elevated with GS+. Methane emissions were not affected (P > 0.05) either by clover supplementation or by clover type in both experiments. This study illustrates that the white and red clovers investigated were widely similar for their effects on N losses and methane emission in dairy cows. Our findings imply that supplementation of white or red clover to a high-protein ryegrass could enhance nitrogen losses to the environment, and would not be beneficial in terms of reducing methane emissions.     

A sensitive bioassay for detection of dietary estrogens in animal feeds

Estrogen-responsive proliferation in the MCF-7 cell line was used as a bioassay for detection of dietary estrogens. The bioassay procedure was adapted to screen for estrogenic activity in feedstuffs that have been associated with hyperestrogenism in livestock. Methanolic feed extracts were added to the cell culture medium at microliter/ml concentrations for 4 days, after which the cell proliferation response was measured as DNA content. The half-maximal response for estradiol occurred at 2 pM, or 0.54 pg/ml. For zearalenone, a weaker estrogen, the half-maximal response occurred at approximately 200 pM, or 64 pg/ml. The bioassay was calibrated against a number of known estrogens (estradiol, diethylstilbestrol, zearalenone, zearalanol [cattle implant], beta-zearalenol, zearalane), including the naturally occurring phytoestrogens (formononetin, genistein, daidzein, biochanin A, and coumestrol). The estrogenic activity of feed samples was expressed as equivalents of zearalenone (ppm zearalenone) that would have to be present to equally stimulate proliferation of the MCF-7 cells. The sensitivity of the bioassay was 0.05-0.1 ppm equivalents of zearalenone in feed, well below the threshold level associated with reproductive problems. The feed additive melengestrol acetate (MGA) showed no estrogenic activity in this assay. Estrogenic activity of feed extracts was confirmed by competitive inhibition with the antiestrogens tamoxifen or LY156758 (keoxifene) to show that stimulation of growth by feed extracts was through an estrogenic mechanism. Confirmation of known estrogens was by tandem mass spectroscopy. The assay is a sensitive and reliable screening procedure for detecting estrogenic activity in feedstuffs.     

不同玉米品种（系）的全株、果穗与秸秆青贮特性比较

为比较不同玉米品系的全株、果穗及秸秆青贮效能和利用特性,以3个粮饲通用玉米新品系和1个专用青贮玉米为材料,于3/4乳线期测定生物产量及相关农艺性状,制作全株、果穗及秸秆青贮,发酵60 d后测定营养成分和发酵品质。结果表明：4个品种（系）生育期变幅为120~123 d,MTP-080生育期最长且绿叶数及绿叶比最高,MTP-082生育期居中但全株和果穗鲜干产量均最高。全株青贮中雅玉青贮8号的中性洗涤纤维和酸性洗涤纤维含量最高,MTP-082粗蛋白、淀粉和可溶性碳水化合物含量均最高,MTP-082泌乳净能显著高于雅玉青贮8号和MTP-080。各品种（系）全株及果穗青贮pH为3.53~4.07,氨态氮/总氮小于10%,费氏评分均在110分以上,青贮发酵品质总体评价均为优级。果穗青贮总能、总可消化养分、消化能、代谢能、维持净能、增重净能及泌乳净能显著高于全株青贮和秸秆青贮。果穗青贮相对饲用价值为全株青贮的2.05倍、秸秆青贮的3.37倍。综上,粮饲通用型青贮玉米如MTP-082全株青贮产量高,持绿性适中,营养价值和发酵品质优,而且是制作果穗青贮的优质原料,因地制宜选择粮饲通用玉米发展果穗青贮将有利于种养殖业节本增效。     

红三叶异黄酮对低温诱发肉鸡腹水综合症发生和抗氧化性能的影响

观察在低温环境下红三叶异黄酮对肉鸡腹水综合症的防治效果及其对肉鸡抗氧化性的影响。300羽肉鸡随机分为3组:常温对照组,低温组、低温黄酮组,采用低温诱发 AS,记录AS发病数,并分别于14,21,28,35和42 d从各组随机抽取6羽肉鸡取样,测定右心肥大指数,红细胞压积,血清和肝脏组织的SOD、MDA和GSH-Px等指标。结果表明环境低温使肉鸡腹水综合症发病率升高,肉鸡日粮添加红三叶异黄酮能够有效地降低寒冷诱发的AS发病率,右心肥大指数和红细胞压积,并提高了抗氧化性能。     

不同栽培年限白三叶产草量的研究

连续3年对不同白三叶品种鲜草产量的测定表明:第一年是白三叶缓慢生长期,第二年和第三年为旺盛生长期,其中海发白三叶是引进品种中表现最好的高产优质牧草,白兰莎白三叶的鲜草产量最低,为一种很好的地被兼观赏植物,作为草坪草观赏是一个好品种。     

Some effects of feeding pasture silage as a supplement to pasture on reproductive performance in lactating dairy cows

Supplementation of a ryegrass/white clover pasture diet with pasture silage is a common management practice in New Zealand dairy herds. The effect of this supplementation on reproductive performance has not been investigated. Five herds of 20 cows were formed before calving commenced on 1 June 1992. From 5 August to 4 September, two of these herds were fed 5 kg/cow/day of pasture silage in addition to the ryegrass/white clover pasture offered to all herds. Pasture silage supplementation did not alter the intervals from calving to first ovulation, first oestrus, or to conception. However, it reduced the first service conception rate (37.5% v. 53.3%; difference +/- sed = 15.8 +/- 10.0%, for pasture and silage and pasture only cows, respectively). A positive effect on reproductive performance of pasture silage supplementation was not demonstrated in this trial.