Effect of molecular weight and concentration of legume condensed tannins on in vitro larval migration inhibition of Haemonchus contortus

The effect of molecular weight of condensed tannins (CT) from a variety of warm-season perennial legumes commonly consumed by sheep and goats on anthelmintic activity has not been previously explored. The objectives of this study were to determine if molecular weight of CT from warm-season perennial legumes could predict the biological activity of CT relative to anthelmintic activity against ivermectin resistant L3 stage Haemonchus contortus (HC) using a larval migration inhibition (LMI) assay. A second objective was to determine if CT from warm-season perennial legumes possess anthelmintic properties against L3 stage (HC). Lespedeza stuevei had the greatest concentration of total condensed tannin (TCT; 11.7%), whereas, with the exception of Arachis glabrata, a CT-free negative control, Leucaena retusa had the least TCT (3.3%). Weight-average molecular weight of CT ranged from 552 Da for L. stuevei to 1483 Da for Lespedeza cuneata. The treatments demonstrating the greatest percent LMI were L. retusa, L. stuevei and Acacia angustissima var. hirta (65.4%, 63.1% and 42.2%, respectively). The ivermectin treatment had the smallest percent LMI (12.5%) against ivermectin resistant L3 HC. There was a weak correlation (R² = 0.34; P = 0.05) between CT M_W and percent LMI, suggesting that molecular weight of CT is a weak contributing factor to CT biological activity as it relates to LMI of L3 stage HC. L. stuevei, L. retusa and A. angustissima var. hirta STP5 warrant further evaluation of anthelmintic properties in vivo.     

A comparative histochemical study of plant polyphenols in southern African grasses

Recent anatomical studies have shown that tannin‐like substances (TLS) occur in the epidermal cells of a number of southern African tropical grasses, and the presence of condensed tannins in grasses has been confirmed by chemical analyses. A number of species from four of the five subfamilies of the Poaceae were compared for their responses to a range of histochemical tests which differ in their specificity for phenolic compounds. These included: ferrous sulphate, acidified vanillin, diazotized sulphanilic acid, Fast Blue‐BB, dimethoxybenzaldehyde and nitrous acid, Safranin and Fast Green. In addition, the radial diffusion test for protein precipitation was used. Comparative histochemical tests indicated that most taxa known to contain TLS showed comparable responses to the tests used here, with variations in intensity and hue of the coloured products formed. These qualitative differences suggest the presence of a number of different compounds including oligomeric procyanidins, oligomeric prodelphinidins, monomeric and/or dimeric flavan‐3‐ols and flavan‐3,4‐diols. The presence flavan‐4‐ols has been confirmed in the andropogonoid grasses by previous workers. Histochemical tests are adequate to identify the presence of condensed tannins and their precursors in plant tissue. However, they do not provide a means to identify those compounds which precipitate protein and function as digestibility‐reducing compounds in plant‐herbivore interactions.     

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.     

Efficacy of condensed tannins against larval Hymenolepis diminuta (Cestoda) in vitro and in the intermediate host Tenebrio molitor (Coleoptera) in vivo

Natural anti-parasitic compounds in plants such as condensed tannins (CT) have anthelmintic properties against a range of gastrointestinal nematodes, but for other helminths such effects are unexplored. The aim of this study was to assess the effects of CT from three different plant extracts in a model system employing the rat tapeworm, Hymenolepis diminuta, in its intermediate host, Tenebrio molitor. An in vitro study examined infectivity of H. diminuta cysticercoids (excystation success) isolated from infected beetles exposed to different concentrations of CT extracts from pine bark (PB) (Pinus sps), hazelnut pericarp (HN) (Corylus avellana) or white clover flowers (WC) (Trifolium repens), in comparison with the anthelmintic drug praziquantel (positive control). In the in vitro study, praziquantel and CT from all three plant extracts had dose-dependent inhibitory effects on cysticercoid excystation. The HN extract was most effective at inhibiting excystation, followed by PB and WC. An in vivo study was carried out on infected beetles (measured as cysticercoid establishment) fed different doses of PB, HN and praziquantel. There was a highly significant inhibitory effect of HN on cysticercoid development (p = 0.0002). Overall, CT showed a promising anti-cestodal effect against the metacestode stage of H. diminuta.     

Chemical composition of Mopane worm sampled at three sites in Botswana and subjected to different processing

Effects of site and degutting on chemical composition of mopane worm were investigated. Samples were cooked for 30 min in either brine or in plain water. Samples from Moreomabele were high in acid detergent fibre (ADF) (P < 0.05) and acid detergent insoluble nitrogen (ADIN) (P < 0.01) while samples from Sefophe had least ADF and ADIN concentrations. In vitro true dry matter digestibility (IVTDMD) tended (P = 0.06) to be high in samples from Maunatlala than those from Moreomabele and Sefophe. No site difference (P > 0.05) was observed on the rest of the variables. Degutted samples had high crude protein (CP), ADF and IVTDMD (P < 0.05) but lower (P < 0.001) concentrations of ash, acid detergent lignin (ADL) and condensed tannins. Acid detergent insoluble nitrogen was significantly higher (P < 0.001) in degutted than whole samples. Salting did not (P > 0.05) change concentrations of all but ADF which tended (P = 0.09) to be high in salted samples. Samples which were degutted and salted had higher (P < 0.01) ADF and ADIN than degutted and salted or those left whole and salted or left unsalted. Leaving samples as whole diluted the concentration of CP but increased the fibre components and condensed tannins content. However, mopane worm destined for livestock feeding may be left whole and salt added.     

高山灌木和牧草缩合单宁含量季节变化动态研究

采用香兰素盐酸法分析了高寒草甸几种优势牧草和灌木中的可浸提缩合单宁含量季节变化动态。试验结果表明,线叶嵩草、阴山扁蓿豆、垂穗披碱草和鹅绒委陵菜等牧草和短叶锦鸡儿不含缩合单宁;珠芽蓼缩合单宁含量高,5个月的平均值为77.56g/kg DM,7月高达120.2g/kg DM;苔草显著低于珠芽蓼(p<0.01),最高时也只有6.7g/kg DM(7月);5种灌木缩合单宁含量各不相同,金露梅、红药柳、高山绣线菊、藏沙棘和鬼见锦鸡儿4个月的平均值分别为(g/kg DM):54、3、58、53、29、18、67.08和42.15,且随着季节推移,各灌木缩合单宁含量逐渐下降;而珠芽蓼和苔草从5月到7月逐渐上升,之后又开始下降。同时,分析了缩合单宁含量与植物的进化及家畜利用富含缩合单宁植物时应注意的事项。     

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.     

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.     

贮藏时间对饲用燕麦种子寄藏真菌及真菌毒素的影响

为明确贮藏时间对饲用燕麦种子中寄藏真菌和真菌毒素的影响,本研究通过平板培养法、形态学观察和rDNA-ITS序列分析法,对3个燕麦（Avena sativa）品种种子携带的真菌进行了分离鉴定;通过高效液相色谱质谱联用法对优势菌属产生的毒性较强的3种真菌毒素细交链孢酮酸（TeA）、黄曲霉毒素B₁（AFB₁）和桔青霉素（CIT）进行了检测和分析。结果表明：饲用燕麦种子的带菌量随贮藏时间的增加总体呈降低趋势。从供试材料中共检出真菌16属34种,优势属为链格孢菌属、曲霉菌属和青霉菌属;带菌种类和分离率随贮藏年限的变化差异显著,不同品种的带菌情况也差异显著;3种真菌毒素随贮藏年限的延长基本呈先升后降的趋势,贮藏年限和品种间的互作对毒素含量的影响最大。综上,贮藏时间对饲用燕麦种子的带菌情况和真菌毒素检出量影响显著。     

种蛋质量和贮存时间对孵化率的影响

对种蛋的质量和贮存和时间对孵化率的影响进行了统计分析。表明：患病种鸡和健康种鸡所产种蛋在孵化率上差异极显著;越是产蛋后期,种蛋贮存时间越长,对孵化率影响越大。     

含水量和劣变时间对高丹草种子活力及幼苗生长的影响

以高丹草种子为材料,研究不同含水量（MC,10%、12%和16%）和劣变时间（0、4、8、12、16、20、24和28 d）处理后种子活力指标（发芽率GP、发芽指数GI、活力指数VI）和幼苗生长指标（苗长SL、苗重SW、根长RL、根重RW、幼苗活力指数SVI）变化,探究含水量和劣变时间对种子活力及幼苗生长状况的影响。结果表明,随含水量由10%升高至16%,劣变4~8 d时,种子GP、GI、VI及幼苗SW、SVI均显著降低;劣变16~28 d时,尽管种子活力指标及幼苗生长指标在12%和16%MC间差异不显著,但均显著低于10%MC的相应指标。随劣变时间延长,种子GP、GI和VI降低,幼苗SL、SW、RL、RW和SVI也降低。16%MC种子的活力及幼苗生长指标在劣变8 d后已几乎降为0,而10%MC种子的GP、GI和VI在劣变28 d时仍分别保持原有水平的10.0%、14.1%和1.5%,且10%、12%和16%MC种子抗劣变时间分别为28、16和8 d,这表明含水量越高,种子活力越容易丧失,抗劣变能力也越差。此外,种子含水量、劣变时间及两者交互作用对种子活力和幼苗生长均具有极显著影响。劣变8 d处理可以较好地评价不同含水量高丹草种子的活力水平。     

贮藏方式和贮藏时间对苜蓿干草霉菌数量和种类的影响

为探讨贮藏方式和贮藏时间对苜蓿(Medicago sativa)干草霉菌数量和种类的影响,本研究在甘肃省酒泉市肃州区采集露天贮藏、苫布贮藏和储草棚贮藏下不同贮藏时间的苜蓿干草,用PD A平皿培养法、形态鉴定法和rD-NA-ITS序列分析法对霉菌的数量和种类进行了鉴定和分析.结果表明:贮藏方式和时间对苜蓿干草的霉菌数量和...     

不同贮藏时间对牧草种子萌发特性的影响

对在室温下贮藏不同时间的17个牧草品种,用常规发芽方法进行了萌发及休眠特性的测定。结果表明:禾本科牧草种子在2个月内基本解除休眠,但不耐贮藏,贮藏5年具有发芽能力的种子只有羽茅;豆科牧草种子休眠期比禾本科长,且耐贮藏,贮藏10年的种子多数仍具有一定发芽能力;其它科种子发芽率随贮藏时间的不同没有相应变化规律。     

新麦草种子贮藏第一年的生活力变化

本试验采用室内培养皿发芽法、电导率法及可溶性糖测定法,对贮藏12个月的新麦草种子的生活力进行了测定。结果表明:自然条件下贮藏的新麦草种子,其发芽势和发芽率变化很大,均随着时间的变化呈先增高后降低的变化趋势,其中以贮藏8个月的发芽率和发芽势最高达88%和39%,自然条件下的最适储藏时间为6～9个月;种子的电导率和可溶性糖含量的变化都不同程度的反映了种子老化程度的表现,在4℃以上与种子活力呈负相关,在4℃以下,由于温度的关系,与种子活力无相关性。     

Anthelmintic activity of Cocos nucifera L. against sheep gastrointestinal nematodes

The development of anthelmintic resistance has made the search for alternatives to control gastrointestinal nematodes of small ruminants imperative. Among these alternatives are several medicinal plants traditionally used as anthelmintics. This work evaluated the efficacy of Cocos nucifera fruit on sheep gastrointestinal parasites. The ethyl acetate extract obtained from the liquid of green coconut husk fiber (LGCHF) was submitted to in vitro and in vivo tests. The in vitro assay was based on egg hatching (EHT) and larval development tests (LDT) with Haemonchus contortus. The concentrations tested in the EHT were 0.31, 0.62, 1.25, 2.5 and 5 mg ml⁻¹, while in the LDT they were 5, 10, 20, 40 and 80 mg ml⁻¹. The in vivo assay was a controlled test. In this experiment, 18 sheep infected with gastrointestinal nematodes were divided into three groups (n = 6), with the following doses administered: G1—400 mg kg⁻¹ LGCHF ethyl acetate extract, G2—0.2 mg kg⁻¹ moxidectin (Cydectin^®) and G3—3% DMSO. The worm burden was analyzed. The results of the in vitro and in vivo tests were submitted to ANOVA and analyzed by the Tukey and Kruskal–Wallis tests, respectively. The extract efficacy in the EHT and LDT, at the highest concentrations tested, was 100% on egg hatching and 99.77% on larval development. The parameters evaluated in the controlled test were not statistically different, showing that despite the significant results of the in vitro tests, the LGCHF ethyl acetate extract showed no activity against sheep gastrointestinal nematodes.     

几种预处理对两种贮藏期线叶嵩草萌发的影响

对室温下保存了 3个月和 6个月的线叶嵩草种子做了不同预处理的发芽试验 ,结果表明 :用青霉素、赤霉素、硫酸预处理 ,保存 3个月的种子均没有发芽 ,保存 6个月的发芽率有所提高 ;用2 0g l的氢氧化钠预处理 3小时 ,种子发芽率可获最高 ,贮存 3个月和 6个月的分别达 45 %和3 7.5 %。     

Effect of blood handling conditions on progesterone assay results obtained by chemiluminescence in the bitch

Assay of blood progesterone (P₄) is commonly practiced to determine the time of ovulation, diagnose luteal insufficiency, and predict time of parturition in bitches. Because of practical constraints, most blood samples cannot be assayed on site immediately after collection. The aim of this work was to evaluate the effects of various sampling and storage conditions on concentrations of P₄ as determined by chemiluminescence immunoassay. The blood of 5 Beagle bitches was collected from the jugular vein to study the effect of the type of collection tube (silicone, lithium heparin, EDTA), the storage time of unseparated or separated plasma (2 h to 14 d), and the number of freeze-thaw cycles (1–10) on P₄. The effect of each factor was tested within one assay session. None of the factors significantly affected P₄. Thus, P₄ appears to remain relatively stable in canine blood samples exposed to various processing and storage conditions.     

贮藏期和添加绿汁发酵液对袋装苜蓿青贮的影响

研究添加不同稀释倍数绿汁发酵液的袋装苜蓿青贮贮藏180 d和400 d后的发酵品质和营养价值。结果表明,添加绿汁发酵液可以显著降低贮藏400 d袋装苜蓿青贮的pH值(P<0.01),乳酸含量极显著增加(P<0.01),乙酸、丙酸、丁酸和氨氮含量极显著减少(P<0.01),而对干物质、中性洗涤纤维、酸性洗涤纤维、粗蛋白质含量及体外消化率的影响不显著;与贮藏180 d相比,贮藏400 d后pH值显著下降(P<0.01),有机酸含量显著增加(P<0.01),中性洗涤纤维和粗蛋白含量显著增加(P<0.01),干物质、中性洗涤纤维、酸性洗涤纤维、粗蛋白质消化率显著提高(P<0.01)。     

蛭石引发对结缕草种子发芽率和发芽速度的影响

试验采用最终发芽率分别为90%(当年收获)、83%(贮藏1年)、74%(贮藏2年)、15%(贮藏3年)的结缕草(Zoysia japonica)种子为材料,以蛭石作为固体引发基质,研究水势和时间对种子最终发芽率、50%发芽时间和平均发芽时间的影响。结果表明,蛭石引发处理对当年收获和贮藏1年的结缕草种子的最终发芽率没有影响,但显著提高了贮藏2年和3年种子的最终发芽率,分别比对照提高了9%和12%;随着引发处理水势的增加和处理时间的延长,4份不同贮藏年限的种子50%发芽时间和平均发芽时间均有不同程度的缩短,分别比对照缩短1.8~3.0 d和2.1~8.2 d。与PEG溶液引发相比,蛭石固体引发最佳处理的水势更高,为-0.4~-0.1MPa;处理时间更长,为3~4 d。