摘要:

AbstractPerennial ryegrass (Lolium perenneL. cv. S23) and white clover (Trifolium repensL. cv. Blanca) were grown in mixed swards, with and without fertiliser N as ammonium nitrate, at 12 sites in the UK. Grass and clover separated from herbage harvested in May, July and September, have been examined for N, S and other major mineral elements, in relation to the nutrition of both the crop and ruminant animals. The total N content was greater in the clover than in ryegrass at each site, both with and without fertiliser N. The S content of the clover was similar to that of ryegrass at the first harvest in May, but was lower in July and September. There were large differences between the species in the ratio N:S, the average being 17.1:1 in white clover and 8.6:1 in ryegrass. The proportions of the total S present as sulphate were higher in ryegrass, with a mean of 48%, than in the clover, with a mean of 16%. The contents of Mg, and particularly of Ca, were higher in clover, while K was generally higher in ryegrass. Consequently, the ratio K: (Ca+Mg) was always at least twice as high in the ryegrass as in the clover. In some of the ryegrass, but none of the clover samples, it exceeded 2.2:1, the value above which there is an increasing risk of hypomagnesaemia in ruminant animals. The content of total cations (Ca + Mg + K + Na) was on average 37% greater in the clover than in the ryegrass, while the content of total inorganic anions (but including organic P) was much less in the clover. The content of organic anions, as calculated from the difference between the contents of total cations and inorganic anions, was at least twice as great in white clover as in ryegrass.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340902

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractDietary fibre buffers the gastrointestinal tract via the inherent buffering capacity of the specific fibre matrix, the quantity of cell wall ingested and the stimulatory effect of cell wall on rumination and/or salivation. The strong bonding of Cu2+ions for carboxy groups permits their use in estimating the cation exchange capacity (CEC) of both pectinaceous materials and pectin‐free cell wall fractions. The CEC values observed emphasise the different cation exchange capacities of the various plant cell wall components. Cellulose has a relatively low exchange capacity while lignin and Maillard products have a much greater adsorption. Emphasis is placed on the difficulty in utilising gravimetric determinations to interpret physicochemical effects as well as the diversity of plant sources in terms of gastrointestinal bufferin

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340903

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractUntreated and formaldehyde‐treated rapeseed meals were subjected to a two‐stage extraction with aqueous and pure acetone. The extraction process significantly reduced the glucosinolate contents of the untreated and formaldehyde‐treated rapeseed meals on a proportional basis by approximately 0.85 and 0.75 respectively. The effect of both solvent extraction and formaldehyde‐treatment upon the utilisation of the rapeseed meal protein was determined using a rat bioassay. Formaldehyde‐treatment did not affect either the true digestibility or biological value of the rapeseed meal protein. However, solvent extraction whilst not affecting true digestibility increased the biological value of both untreated and formaldehyde‐treated rapeseed meals significantly by

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340904

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe surface topography of lupulin glands was studied at various stages of maturity using scanning electron microscopy. Maximum gland filling coincided with maximum alpha‐acid concentration and dry matter yield. The percentage of the different components of oil remained constant after maximum gland filling had occurred. Dry matter content of hops at maximum gland filling varied from year to year and was not an accurate guide to optimum harvest dat

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340905

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of intramolecular short‐chain fatty acids on the abomasal hydrolysis of long chain acyl ester bonds has been examined using four different fats. An evaluation of abomasal infusion of feeds as a technique to avoid hydrolysis of fat by salivary lipase has been made. Only calves considered to be typically functional preruminants were used for the investigations. Five preruminant calves each received five experimental milk feeds consisting of skim milk plus 3% of either butter oil, coconut oil, palm oil or tallow. All feeds were given by mouth but the feed that contained butter oil was also introduced directly into the abomasum via a simple cannula. In all cases, digesta leaving the abomasum were continuously sampled for 12 h via a re‐entrant cannula in the proximal duodenum, anterior to the entry of the bile and pancreatic ducts. Butter oil given by mouth was hydrolysed to a greater extent than the other fats. This was due not only to the ease of liberation of the short chain fatty acids, but also to an enhanced liberation of longer chain acids when short chain acids are present in the triglyceride. Butter oil introduced directly into the abomasum of truly preruminant calves was not hydrolysed, suggesting that by using this technique studies could be made in vivo of the hydrolysis of fat by pancreatic lipase al

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340906

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340907

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340908

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of germination at 25 °C for 96 h in the dark on the carbohydrates of fenugreek seed was investigated. Reducing, total reducing, non‐reducing sugar, and pentosan contents increased. Polysaccharides estimated as starch decreased. Fenugreek contained mucilage (18%), which decreased considerably during germination. The decline in mucilage content was accompanied by a drop in galactan content. Total pectic content did not change, but there was a decline in the high methoxy pectin content, while protopectin, and the low methoxy pectate salts of calcium and magnesium increased. The 70% ethanol soluble carboydrates were chromatographically determined. Fenugreek seeds contained sucrose, raffinose, stachyose, and an unidentified sugar (I). A marked increase in sucrose content was observed after germination. Raffinose, stachyose and the unknown sugar (I) decreased, while another unknown (II) appeared. The two unknown sugars may be members of the raffinose family. Maltose and fructose appeared in measurable amounts after germinati

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340909

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe determination of the endogenous urinary nitrogen (EUN) excretion in protein quality studies using the Thomas‐Mitchell method with rats has usually been estimated using either a protein‐free or low concentration egg protein diet. Generally no effort has been made to equate EUN excretion with the urinary nitrogen excretion in the urine whilst the rat is in a state of maintenance. An attempt was made to find the diet which would maintain the weight of the rats used to determine the EUN at the time of the balance period of the protein quality test animals. It was found that a diet containing 20 g egg albumen kg−1came the nearest to fulfilling this criterion and was the diet most suitable for the determination of th

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340910

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractSugar composition of hemicelluloses before and after in‐vitro digestion of sorghum at different stages of maturity have been determined. Xylose was the main mono‐saccharide residue and its content increased with maturity. It was also the least digestible sugar residue. Galactose and arabinose residue were highly digestible at all stages of matur

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340911

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY