Cell-Constituents,Tannin Levels by Chemical and Biological Assays and Nutritional Value of Some Legume Foliage and Straws

Twenty six straw and 15 foliage samples of Lathyrus sativus , Vicia narbonensis , V sativa and V ervilia were analysed for ash, crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), extractable phenols (Pe), extractable tannins (Te), extractable condensed tannins (CTe), protein precipitation capacity (PPC) and in vitro characteristics predicted from Hohenheim gas test. The content of crude protein in the foliage was significantly higher than that of the straws (152·6 vs 64·5 g kg⁻¹), while ash (82·8 vs 116·8 g kg⁻¹), NDF (332·7 vs 523·5 g kg⁻¹) and ADF (205·2 vs 369·9 g kg⁻¹) were significantly lower. For straws of L sativus , V narbonensis and V sativa , there was no significant difference in the protein and ADF contents, whereas ash and NDF contents were significantly lower and higher respectively in L sativus as compared to V narbonensis or V sativa . Predicted from gas volumes, the organic matter digestibility (OMD: 70 vs 56%) and metabolisable energy (ME: 9·7 vs 7·3 MJ kg⁻¹) were significantly higher for the foliage compared to straws. The OMD of L sativus straws was significantly lower compared to the straws of V narbonensis and V sativa . The OMD and ME of the straws of second year was significantly lower than those of the first year. The CP, OMD and ME of V sativa foliage were higher than that of V narbonensis . There was no difference in the cell constituents, OMD and ME of foliage samples of V sativa harvested in May 1992 and June 1992. The contents of Pe, Te and CTe of straws were 1·08%, 0·43% and 0·33%, respectively, and those of foliage were 2·27%, 1·30% and 1·63%, respectively. PPC was not detected for any of the foliage and straw samples. The results suggested that the tannin levels of legume straws investigated are negligible and those of the legume foliage are very low. This does not appear to adversely affect their nutritive value since the maximum decrease in OMD by the tannins was about 3% units.     

In vitro effects of and interactions between tannins and saponins and fate of tannins in the rumen

The rate of fermentation of hay was not affected by purified tannins from Ouercus incana and Dichostachys cinerea at 0.13 mg ml^?1 of the in vitro medium whereas a decrease of 4% in the rate was observed for Acioa barteri tannins at this level. At 0.23 mg and 0.47 mg of tannins per ml, the decrease in rate varied from 4 to 13% and 13 to 20%, respectively. The decrease in in vitro true digestibility of dry matter was 3, 6 and 7% for Q incana, D cinerea and A barteri, respectively, at a tannin concentration of 0.47 mg ml^?1, and 17, 21 and 27%, respectively, at 0.93 mg ml^?1. There was no change in the potential extent of digestion up to 0.47 mg ml^?1 for any of the tannins studied. These results suggested that the rate of digestion is affected to a greater extent than the potential extent of digestion or the in vitro true digestibility and that different tannins even at the same level have different degrees of effect. Tannin-saponin interactions were studied using tannic acid (TA), quebracho tannin (QT) and quillaja saponin (S) at different concentrations (0.2, 0.4 and 0.6 mg ml^?1) alone and in combination with each other. The decrease in the rate of digestion and true digestibility was additive when both the TA and the S were present. Similar results were obtained when TA was replaced by QT except that the effects with QT were more marked as compared to TA at the same concentration. Saponins had little effect on the potential extent of digestion and true digestibility. These tannins also decreased the production of short-chain fatty acid (SCFA) and their molar proportions (acetate decreased whereas propionate increased). Efficiency of microbial protein synthesis, expressed as the ratio of ¹⁵N incorporation per unit of SCFA production, was higher with both S and the tannins studied. A substantial amount (71–93%) of tannins soluble in aqueous acetone was released from leaves of some trees and shrubs on incubation in the in vitro medium for 48 h. The rumen liquor was not capable of degrading oligomeric condensed tannins.     

Degradation of condensed tannins by rumen microbes exposed to quebracho tannins (QT) in rumen simulation technique (RUSITEC) and effects of QT on fermentative processes in the RUSITEC

In an earlier study it was observed that the rumen microbes from cattle which had never consumed tannin-containing diets do not have enzymes for degrading condensed tannins. In this study, rumen microbes were exposed to small amounts of quebracho tannins for 8 days using a rumen simulation technique (RUSITEC). The levels maintained in the RUSITEC were 0.1, 0.2 and 0.4 mg of the spray-dried quebracho powder (SDQT) per ml of the medium. After 8 days of tannin exposure, the liquor containing ‘exposed/adapted’ microbes from RUSITEC was incubated for 40 h without and with purified tannins of quebracho and Dichostachys cinerea leaves in in vitro gas method. There was no degradation of condensed tannins. The enzymes for degradation of condensed tannins were not induced in rumen microbes by exposure to different concentrations of tannins for 8 days in the RUSITEC. In the RUSITEC, SDQT significantly reduced the number of total protozoa, entodiniomorphs and holotrichs; effect was higher on holotrichs. There was no significant change in the levels of short chain fatty acid but the molar proportion of propionate was significantly higher and of butyrate significantly lower at 0.4 mg SDQT ml^?1. Significantly lower levels of ammonia in the medium was also observed on injection of tannins. Microbial mass production, calculated using ¹⁵N incorporation, was similar at 0.1 and 0.2 mg SDQT ml^?1 but significantly lower (13%) at 0.4 mg SDQT ml^?1. The dry matter digestibility of the feed (80% hay and 20% barley) was not significantly affected by SDQT.     

Acacia saligna as a fodder tree for desert livestock and the interaction of its tannins with fibre fractions

Acacia saligna was examined as potential fodder for sheep (27.4 kg) and goats (14.8 kg) raised in arid and semi-arid areas. This leguminous tree remains green all year and can be grown in deserts using only runoff water. Phyllodes collected in March had a crude protein content of 12.5% dry matter (DM) and high tannin content (tannins as tannic acid equivalent to 11.3% and condensed tannins as leucocyanidin equivalent to 8.3% DM). DM intake was low, amounting to 0.80% and 1.05% body mass daily for sheep and goats, respectively. Sheep lost 227 g day^?1 and goats 196 g day^?1 while on this diet. Dry matter, organic matter and energy digestibilities were low in both species but were higher for goats than for sheep, and negative digestibilities were measured for acid detergent fibre (ADF) and acid detergent lignin (ADL). Metabolisable energy intake for goats was 121.9 kJ kg^?0.75 day^?1 and for sheep was 78.6 kJ kg^?0.75 day^?1. Apparent N digestibility was 17.5% and 0.9% for goats and sheep, respectively, and both species were in negative N balance of 0.25–0.30 g kg^?0.75 day^?1. Total water intake and output were higher in sheep than in goats. Extractable tannins were virtually absent in faeces in both species, however, output of condensed tannins and protein in the ADF and ADL fractions were substantially higher. This showed the presence of tannin-protein complexes in these fractions which explained the negative digestibilities of ADF and ADL. It was concluded that Acacia saligna could not be used as a sole dietary source for small ruminants because of low intake and negative nitrogen balance. This was due mainly to the high tannin content. However, the tree might have a potential as a supplementary fodder due to its high crude protein content.     

串行12位ADC与PC之间的接口电路

近几年来,IC制造商设计了实现接口的各种方法,并且特别重视减少IC接口I/O引脚的数量。MAX187就是这样一个器件,它是一个12位模/数转换器(ADC)。你可以利用串行数据通信技术产生与该ADC的一个接口。MAX187的模/数转换和数据传输仅需三条数字I/O线。你可以利用PC的Centronics打印机端口在MAX187和PC之间产生一个简易接口(图1)。只要将引脚分别设置为高电平或低     

Non-starch polysaccharides and their role in fish nutrition – A review

The success and sustainability of aquaculture depends on minimising the operational cost of feed that in general comprises 50–60% of the total cost in intensive farming. The major feed ingredient, fish meal, is expensive and there is increasing competition with other livestock industries for the available static supply of fish meal. Hence, the incorporation of plant-derived materials in fish feeds is receiving increasing attention. One of the main constraints in the utilisation of plant ingredients in aquaculture is the presence of indigestible carbohydrates, which consist primarily of non-starch polysaccharides (NSPs). These form a part of the cell wall structure of cereals and legumes. The presence of NSPs in the diet interferes with feed utilisation and adversely affects performance of the animal. Supplementation of NSP-degrading enzymes in feed mitigates the adverse effects of NSPs. The effects of NSPs in pigs and poultry have been widely studied; however little information exists for fish. This review synthesizes the available information on fish and highlights the knowledge gaps. It is hoped that this review will provide a momentum to the research on the roles of NSPs in fish nutrition and physiology and on the efficient use of NSP-degrading enzymes.     

Factor analysis of the functional properties of rice flours from mutant genotypes

A set of 27 waxy rice genotypes and 52 rice genotypes with medium and high amylose contents were screened for various functional properties of flour. In this study, 68 genotypes containing various amylose contents (1.2–30.4%) were mutants of the rice variety TNG67 widely grown in Taiwan. The proximate composition, pasting, thermal and textural properties of rice flours were determined and analysed with factor analysis to assess the genetic differences. A wide variation in various functional properties was observed. Factor analysis indicated that four factors relating to amylose content, gel textural, gelatinization and protein content could explain 80% of the variability among 79 rice flours. Correlation studies and scatter diagrams also indicated the larger role of amylose with respect to protein and lipid in determining the rice flour quality. The present study can be used for readily identifying differences between rice genotypes for eating/cooking quality.     

Protein concentrate from Jatropha curcas screw‐pressed seed cake and toxic and antinutritional factors in protein concentrate

BACKGROUND: Jatropha curcas seeds are highly toxic to livestock. The presence of phorbol esters and antinutrients such as trypsin inhibitor, lectin and phytate and the high level of shells in the seed cake prevent its use in animal diets. Using the principle of isoelectric precipitation, the conditions for preparation of the protein concentrate from oil‐containing seed cake and defatted seed cake were optimised and the contents of phorbol esters and antinutrients were determined. RESULTS: The recovery of protein concentrate was highest when the proteins from the seed cakes were solubilised at pH 11 for 1 h at 60 °C and the precipitation of these proteins was done by lowering the pH to 4. Under these conditions, over 53% of the total proteins present in the seed cakes were recovered in the protein concentrates. The protein contents in the protein concentrates obtained from the oil‐containing seed cake and defatted seed cake were 760 and 820 g kg^?1 respectively. Substantial amounts of phorbol esters were present in the protein concentrates (0.86–1.48 mg g^?1). Trypsin inhibitor was present at an approximately tenfold higher level in the protein concentrates than in the seed cakes. Lectin and phytate were also present at high levels, but their levels were lower than in the seed cakes. Tannins were present in negligible amounts. CONCLUSION: To make the protein concentrate from Jatropha seed cake fit for use as an ingredient in livestock feed, phorbol esters must be removed and trypsin inhibitor and lectin inactivated by heat treatment. The adverse effects of phytate could be mitigated by addition of phytase in the diet. Copyright © 2008 Society of Chemical Industry     

Changes in tannin content,polymerisation and protein precipitation capacity in oak (Quercus incana) leaves with maturity

Changes in the content of total phenolics, condensed tannins, proanthocyanidins and flavan-4-ols, the degree of polymerisation, the protein precipitation capacity, the protein-precipitable phenolic content and the specific activity (protein: tannin in the complex) were determined in Quercus incana leaves with maturity. Total phenolic content and protein precipitation capacity decreased whereas the levels of condensed tannins, proanthocyanidins, flavan-4-ols and degree of polymerisation increased with maturation. The protein-precipitable phenolic content was highest in young leaves and decreased as leaves matured. The specific activity decreased slightly. The results suggest that young leaves would be more toxic to livestock than mature leaves.     

Dietary roles of non-starch polysachharides in human nutrition: a review

Nonstarch polysaccharides (NSPs) occur naturally in many foods. The physiochemical and biological properties of these compounds correspond to dietary fiber. Nonstarch polysaccharides show various physiological effects in the small and large intestine and therefore have important health implications for humans. The remarkable properties of dietary NSPs are water dispersibility, viscosity effect, bulk, and fermentibility into short chain fatty acids (SCFAs). These features may lead to diminished risk of serious diet related diseases which are major problems in Western countries and are emerging in developing countries with greater affluence. These conditions include coronary heart disease, colo-rectal cancer, inflammatory bowel disease, breast cancer, tumor formation, mineral related abnormalities, and disordered laxation. Insoluble NSPs (cellulose and hemicellulose) are effective laxatives whereas soluble NSPs (especially mixed-link β-glucans) lower plasma cholesterol levels and help to normalize blood glucose and insulin levels, making these kinds of polysaccharides a part of dietary plans to treat cardiovascular diseases and Type 2 diabetes. Moreover, a major proportion of dietary NSPs escapes the small intestine nearly intact, and is fermented into SCFAs by commensal microflora present in the colon and cecum and promotes normal laxation. Short chain fatty acids have a number of health promoting effects and are particularly effective in promoting large bowel function. Certain NSPs through their fermented products may promote the growth of specific beneficial colonic bacteria which offer a prebiotic effect. Various modes of action of NSPs as therapeutic agent have been proposed in the present review. In addition, NSPs based films and coatings for packaging and wrapping are of commercial interest because they are compatible with several types of food products. However, much of the physiological and nutritional impact of NSPs and the mechanism involved is not fully understood and even the recommendation on the dose of different dietary NSPs intake among different age groups needs to be studied.