摘要:

AbstractChanges in amino acid fractions of chopped low‐to‐medium protein whole‐crop wheat were studied at four stages of maturation and at two stages after a 24 h wilting period. Tests were carried out after an ensiling period of 90 days, and after a further 7‐day post‐fermentation aerobic exposure. Total amino acids contents in the dry matter during the fermentation period remained stable. Quantities of essential amino acids decreased during maturation and fermentation and remained stable during post fermentation aerobic exposure. The highest amino acid concentrations recorded in the fresh material were those of arginine, lysine, glutamic acid, alanine, leucine, glycine and aspartic acid. Free amino acids varied from a low level in the fresh material<10% of the total amino acids toca65% after the aerobic process. Ammonia‐N content increased in the silage and remained relatively stable on post fermentation aerobic exposure. The concentration of all free amino acids increased except arginine and glutamine during the ensiling period and post fermentation aerobic exposure. After wilting, an increase in free amino acids and a decrease in insoluble amino acids was recorded. The changes in concentration of 18 amino acids during ensilage and following post fermentation aerobic exposur

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340402

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe sodium, potassium and chloride contents of feedingstuffs used in practical and purified diets are reported. The sodium contents of some cereals and cereal by products are considerably lower than those in the literature.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340403

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractWeighted‐meanL‐values and uptakes of P by plants were determined using ryegrass grown in a controlled environment on soils obtained from long‐term field experiments at Rothamsted (Batcombe and Winchester soil series), Woburn (Stackyard and Cottenham series) and Saxmundham (Beccles series) given different organic and inorganic manurial treatments. Linear regression analysis showed that, under the experimental conditions used, (small soil volume, weekly additions of all nutrients other than P) initial soil NaHCO3‐soluble P accounted for more than 95% of the variance of plant‐P uptake and weighted‐meanL‐values. The relationships between NaHCO3‐soluble P, plant‐P uptakes and weighted‐meanL‐values (labile P) were all independent of soil type and form of P fertiliser applied. In most soils,L‐values increased with increasing cut number, and the rate of increase was linearly related to initial soil NaHCO3‐soluble P, suggesting that NaHCO3‐P measurements may provide useful information on the availability of initially non‐isotopically exchangeable soil‐P reserves. The plants removed about 68% more P from the soils than was measured as initially NaHCO3‐soluble and about one‐half the labile soil‐P. Labile soil‐P was 3.5 times greater than initial NaHCO3‐soluble P. The initial soil NaHCO3‐soluble P required to provide at least 95% of maximum yield increased with increasing cut number (from 37 mg P kg−1 soil at cut 1 to 160 mg P kg−1soil at cut 4), probably because the NaHCO3‐P pool was repleni

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340404

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractInsect feeding trials were carried out whereby cowpea trypsin inhibitor (CPTI) was incorporated at various levels up to 10% in pelleted meals of both a susceptible variety of cowpea and another susceptible species of legume, the chickpea. The results confirmed that CPTI, prepared by affinity chromatography, is an effective antimetabolite againstC. maculatus;furthermore, it is also effective when added to pelleted chickpea meals. Bioassays using soya bean trypsin inhibitor (SBTI) and lima bean trypsin inhibitor (LBTI) showed these protease inhibitors to be relatively ineffective. Methionine supplementation of meals of resistant cowpea resulted in increased adult survival from approximately 43 to 89% relative to the controls; addition of cysteine had a similar effect. Supplementation with both methionine and tryptophan, probably the next limiting amino acid in cowpea, did not increase adult survival any further. It is concluded that CPTI is an effective antimetabolite ofC. maculatusand that this type of mechanism may be widespread. However, it relies upon a finely controlled balance within the host plant which has to make available sufficient nutrients for itself but insufficient to maintain predation since this example of resistance can be overcome by by‐passing the limiting sulphur amino‐acid bl

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340405

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractPigs (53‐70 kg) in a non‐fasted state were either not transported or subjected to a journey lasting for 1 h or 6 h prior to slaughter. Pigs given the short transport lost 0.6% and pigs given the long transport 2.3% of their initial live weight. After lairage for 1 h with access to water, all pigs were killed 8 h after their last feed. Compared with pigs not transported before slaughter, killing out percentage was slightly, but not significantly, lowered in the short transport group and significantly (P<0.05) reduced in the long transport group. The loss in carcass weight of the latter group amounted to 2.1% of the carcass weight of the untransported control pigs. Overall, killing out percentage and liver weight expressed as a percentage of liveweight were negatively correlated with the percentage loss of live weight in transport (P<0.02). The carcass weight loss on chilling was not influenced by treatment. Measurements of adrenal ascorbic acid suggested that most of the stress of transport occurred during the loading and first hour of the journey. Transported pigs drank more water in lairage, particularly those transported for 6 h which also had a higher total protein concentration in their plasma (P<0.05). Plasma creatine phosphokinase activity was not influenced by transport. It is suggested that enforced deprivation of water is an important contributing factor to the weight loss of pigs during transport but that physical activity is

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340406

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of sulphur fertilisation on yield and herbage composition was investigated in two successive years at two grassland sites, one with ryegrass and one with ryegrass/ clover, where the available sulphur in the soil was less than 10 mg kg−1. When supplies of N, P and K were not limiting, herbage yields increased with added sulphur at both sites, particularly at the second and third cuts and in the second year. Sulphur additions also increased the concentrations of total S and SO4−2−S in the crop, and reduced the N:S ratio. The figures for these parameters in herbage from control plots confirmed that low yields in the presence of normal nitrogen fertilisation were probably caused by sulphur defic

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340407

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractTwo approaches were used to study the aggregation states of prolamins extracted from milled whole grain of wheat, barley, rye and maize with 500 ml litre−1aqueous propan‐1‐ol. In the first, a comparison was made of the electrophoretic patterns of the samples separated by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS‐PAGE) under reducing and non‐reducing conditions. In the second, they were chromatographed on a column of controlled pore glass (CPG) using a modified acetic acid, urea, cetyltrimethyl ammonium bromide (AUC) solvent and aliquots of the major peaks were reduced and analysed by SDS‐PAGE. When the CPG chromatography was repeated under reducing conditions some of the peaks were eliminated indicating that they were composed of disulphide‐linked aggregates. The results from both approaches showed that in barley, rye and wheat the HMW prolamins and some of the S‐rich prolamins (B hordein, some γ‐secalins and subunits of high molecular weight gliadins) are present predominantly or partially in high molecular weight (above 1 × 106daltons) aggregates which appear to be stabilised by disulphide bonds. Other S‐rich prolamins (including some γ‐secalins, α, β and γ‐gliadins) and all the S‐poor prolamins (‘C’ hordein, ω‐secalin, ω‐gliadin) are present predominantly or only as monomers. These results are discussed in relation to the structural and genetic homology of the prolamins in the three species. Although prolamin aggregates are also present in m

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340408

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractA comparison was made of the effectiveness of various solvents in extracting protein from wheat gluten. The best proved to be 0.055m cetyltrimethyl ammonium bromide‐6m urea‐0.01m acetic acid. When extracts were separated on columns of controlledpore glass, with a nominal exclusion limit of 1.2 × 106daltons for molecules in the extended form, two peaks were obtained termed F1 and F2. F1 was excluded from the column and contained material which was stable in the absence of reducing agent but was markedly reduced in size in the presence of 2‐mercaptoethanol. SDS‐PAGE showed that F1 was enriched in high molecular weight polypeptides (about 100 000 daltons) and also contained polypeptides with molecular weights in the range 30 000–45 000. F2 consisted almost entirely of polypeptides with molecular weights of less than 50 000. The ratio of F1 :F2 in different varieties varied from 0.1 to 0.58 and this variation was correlated with the NIAB potential breadmaking quality score. However, there did not appear to be any difference between the total amounts of high molecular weight polypeptides in a poor and a good breadmaki

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340409

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractExperiments were conducted to study the metabolic fate of γ‐HCH used in pig husbandry, and to see if a relationship existed between its use and the occurrence of 1,4‐dichlorobenzene and other chlorobenzenes in pork meat. Both oral administration and spray application of γ‐HCH led to the rapid accumulation of γ‐HCH and several metabolites in the adipose tissue. The following compounds were identified by gas chromatography and mass spectrometry: monochlorobenzene, 1,2‐, 1,3‐ and 1,4‐dichlorobenzene, 1,2,4‐trichlorobenzene, 1,2,4,5‐, 1,2,3,5‐ and 1,2,3,4‐tetrachlorobenzene, pentachlorobenzene, γ‐3,4,5,6‐tetrachlorocyclohexene, γ‐2,3,4,5,6‐penta‐chlorocyclohexene and α‐hexachlorocyclohexane. Concentrations of residual γ‐HCH and its metabolites were related to the amount of γ‐HCH applied initially to the pigs. γ‐HCH residues and the metabolites were monitored by biopsy and were found to be eliminated rapidly from the adipose tissue, such that pigs sprayed once with a dose 16 times greater than the recommended rate had a residual γHCH concentration, 30 days after treatment, no greater than that in untreated controls. The origin of 1,4‐dichlorobenzene and other chlorobenzene compounds is discussed in relation to the low levels of these com

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340410

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe oils from the edible flesh, frame, head, skin and viscera of seven deep‐sea fish namely, alfonsino (Beryx splendens), cardinal fish (Epigonussp.) javelin fish (Lepidorphynchus denticulatus), lookdown dory (Cyttus traversi), rattail (Coelorynchussp.), ribaldo (Mora pacifica) and sea perch (Helicolenus papillosus) were examined. The fatty acids analysed are present as glycerol‐based lipids and no marine wax esters were detected. The distribution of the major fatty acid moieties, i.e. 16:0, 18:1 and 22:6 resembled the pattern common to established commercial fish o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340411

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY