摘要:

AbstractSix techniques were investigated to find a quick, reliable laboratory method for the prediction of the in‐vivo digestibility of animal feeds. Four of these techniques comprised two digestions, one with pepsin in hydrochloric acid followed by another with cellulase. In three cases the cellulase was derived fromTrichoderma viridewhich was used at two concentrations; in addition, at one of these concentrations a step using amyloglucosidase was introduced. In another technique cellulase derived fromAspergillus nigerwas tested to determine how effectively it dealt with starchy materials. The fifth technique comprised the separation of the cell walls by digestion with neutral detergent solution followed by digestion with cellulase (derived fromT. viride) with an additional step using amyloglucosidase for samples containing starch. The last method was an in‐vitro technique using buffered rumen liquor followed by pepsin in hydrochloric acid. Because this technique proved to estimate digestibility more accurately than any of the simple chemical methods it provided a guide to the efficiency of the enzyme techniques. The digestible organic matter in the dry matter (DOMD) was determined in each case and correlated against the DOMD value obtained using an in‐vivo technique. Two of the methods showed as good a prediction of DOMD as the in‐vitro method using rumen liquor, and the correlation coefficients were comparable. The repeatability of the methods calculated as the coefficient of variation varied between 2.5 and 3.7%. For roughages containing little or no starch the shorter techniques provided an adequate evaluation of DOMD. Starches in the cereals were adequately broken down only when the additional digestion using an amyloglucosidase (Agidex) was included; this is illustrated by the correlation values o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330802

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThin‐layer chromatography of extracts of raw and treated pig slurries revealed the presence of phenolic acids. The number of phenolic acids present in raw slurry was reduced considerably by aeration and, to a smaller extent, by treatment with hydrogen peroxide; anaerobic storage and digestion proved ineffective for the removal of phenolic acids from pig slurr

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330803

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractGlycinin and β‐conglycinin, globular proteins present in soya bean meal, were denatured by extracting the meal with ethanol under several different conditions of alcohol concentration and temperature. Antigenic activities of these proteins in saline extracts of the processed meal were determined by haemagglutination inhibition assay and immunoelectrophoresis. Products extracted with low (96%) concentrations of ethanol at 70–80°C retained antigenic activity, whereas samples prepared with 55–76% ethanol at 70–80°C contained very little extractable antigenic protein. Antigenic activities of glycinin and β‐conglycinin were relatively high in products extracted with concentrations of ethanol between 57–86% when the extraction tempe

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330804

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA method is described for the removal of copper from copper‐rich effluents such as pot ale—a waste product from malt whisky distillation in copper stills. This method makes use of cementation on aluminium metal, obtained cheaply from aluminium beer cans, and could be of potential practical value for the detoxification of copper‐rich effluents such as pot ale and pig slurry before disposal to agricultural land. Traces of silver, gold and platinum have been found in pot ale by a spark source mass spectrographic technique which also uses a cementation procedure to pre‐concentrate trace elements on to aluminiu

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330805

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe tryptophan contents of a range of raw materials which are commonly included in poultry diets have been determined by a modification of a previously published procedure. It is based on the enzymic release of tryptophan from the protein source and its subsequent reaction with dimethylaminocinnamaldehyde. The values obtained for the animal protein sources, cereals and soya bean meal agree well with previously published data. However, the tryptophan contents of other vegetable proteins agree less well with values published elsewhere and that for rapeseed meal is considerably lower. The method is suitable for application in a quality control laboratory where one operator can process eight samples daily.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330806

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractSteers, fitted with simple rumen and duodenal cannulas, were given a basal diet of approximately equal parts of straw and flaked maize [containing 12 g N kg−1dry matter (DM)] or similar diets in which part of the flaked maize was replaced by different amounts of untreated (UT) casein or formaldehyde‐treated (FT) casein to give low (L), medium (M) or high (H) intakes of nitrogen (19, 26 and 34 g N kg−1DM, respectively). Rumen bacteria, separated from samples of rumen digesta taken about 4 h after giving a feed of the basal diet, contained approximately 160 g α‐dextran‐glucose (‘starch’) and 300 g crude protein (CP) kg−1DM. Bacteria from steers receiving the highest level of FT or UT, contained approximately 140 and 70 g ‘starch’ and 320 and 580 g CP kg−1DM, respectively. It was calculated that bacteria contributed approximately 65, 50 and 30 g ‘starch’ day−1at the duodenum of steers receiving basal, FT casein and UT casein diets, respectively. Of the total carbohydrates entering the small intestine, all the rhamnose and ribose and approximately 50–65% of the mannose, galactose and ‘starch’ were contributed by the bacteria, the remainder being dietary in origin. Virtually all the xylose, arabinose and cellulose‐glucose were contributed by surviving dietary materials. For steers receiving the basal ration, mean coefficients of digestibility between mouth and duodenum (corrected for bacterial contribution) were 0.91, 0.97, 0.79, 0.43, 0.22 and 0.41 for mannose, starch‐glucose, galactose, arabinose, xylose and cellulose‐glucose, respectively. Coefficients of digestibility for diets supplemented with FT caseins were not appreciably different from those obtained with basal diets, but for diets supplemented with UT caseins those of arabinose, xylose and cellulose‐glucose were significantly incr

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330807

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe following are summaries of papers presented at a joint meeting of the Agricultural Group and the Fertiliser Society of the Society of Chemical Industry held on 19 October 1981 at the Society of Chemical Industry, 14 Belgrave Square, London SW1X 8PS. The papers so published are entirely the responsibility of the authors and in no way reflect the views of the Editorial Board of theJournal of the Science of Food and Agriculture.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330808

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractNear‐infrared reflectance analysis was used to measure protein and moisture contents of UK wheat samples over five harvests (1975–1979 inclusive). The use of universal constants produced stable instrument calibrations valid for both hard and soft varieties and all growing locations in the UK which required no more than an annual bias adjustment except for 1976, a year when unusual climatic conditions prevailed in UK. The universal calibrations were achieved by the statistical selection of stable subsets of wavelengths. The accuracy of the calibrations when compared with classical methods (oven drying and Kjeldahl) was 0.25% or better for both moisture and prot

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330809

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractTwo experiments have been carried out in which different forms of sunflower oil were added to the diet of Ayrshire heifers. In experiment 1, the animals were given a fat‐depressing diet of dried, ground grass cubes and flaked maize. When either free sunflower oil or milled, unextracted sunflower seeds were added to this diet, the yield of milk fat and of all fatty acids up to 16:1 was decreased and the yield of all 18‐carbon fatty acids was slightly increased. When the sunflower oil was protected by encapsulation in formaldehyde‐treated casein, the yield of milk fat was increased, that of the fatty acids up to 16:1 was decreased and that of all the 18‐carbon fatty acids, and in particular, of the polyunsaturated fatty acids was increased. In experiment 2, the animals were given a basal diet of grass silage and concentrates to which increasing amounts of protected sunflower oil were added. This tended to increase the yield of milk fat and to reduce that of the fatty acids up to 16:1. The yield of all the 18‐carbon fatty acids increased and, in particular, that of the polyunsaturated fatty acids increased progressively as more protected oil was added. It is concluded that it should be possible to produce a milk with any desired proportion of polyunsaturated fatty acids by adding a predetermined amount of protected oil to the diet o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330810

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractModification in the sorghum grain endosperm during seedling growth and malting was found to be associated mainly with increased activities of α‐amylase, endo‐β‐glucanase, limit dextrinase and endoprotease. The major starch‐degrading enzyme was α‐amylase. The activities of endo‐β‐glucanase, limit dextrinase and endoprotease were comparatively higher in the endosperm than in the embryo during seedling growth. Endo‐β‐glucanase activity appeared to be relatively low during seedling growth. The low activity of this enzyme might be partially responsible for the limited degradation of the cell walls in the endospe

ISSN:0022-5142    

DOI:10.1002/jsfa.2740330811

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY