bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth and liver enzyme response in growing rats to graded levels of methionine plus cystine in fortified-barley diets. Response at constant methionine :cystine
Authors: Ngwira T. N. , Beames R. M. 
Published: June 2005

1. Twenty-eight male rats of initial age 27 d were fed on fortified-barley diets for 3 weeks. In all experimental diets, both crude protein (nitrogen × 6.25) and methionine:cystine were constant at 1200 g/kg dry matter (DM) and 2: 1 respectively. The basal diet contained 45 g methionine plus cystine/kg DM with L- methionine plus L-cystine (2: 1, w/w) added in increments of 0.5 g/kg DM to a final level of 70g methionine plus cystine/kg DM. A ‘positivecontrol’ diet of barley plus 193.7 g soya-bean meal/kg DM contained 6.0 g methionine plus cystine/kg DM.2. Weight gain, food conversion efficiency (FCE), urinary urea-N excretion, carcass composition and activities of liver cystathionine synthase (EC 4.2.1.22) and N6-methyltetrahydrofolate-homocysteine-methyltransferase (EC 2.1.1.13) were determined.3. Weight gain, food consumption, FCE and carcass composition measurements of rats showed either small or no differences between the experimental diets containing 4.5–7.0 g methionine plus cystine/kg DM. For the over-all period, weight gain and FCE of rats receiving the ‘positive control’ diet were significantly higher than values obtained with rats receiving any of the experimental diets.4. Cystathionine synthase activity (μmol/mg protein per 60 min; units) increased from 13.38 at 4.5 g dietary methionine plus cystine/kg DM to 18.81 at 5.0 g dietary methionine plus cystine/kg DM. The activity was then inhibited to reach a minimum value of 10.16 units at the 6.0 g/kg DM dietary level. Thereafter the activity increased to a value of 3000 units at 7.0 g dietary methionine plus cystine/kg DM.5. The activity of N5-methyltetrahydrofolate-homocysteine-methyltransferase was constant at 0.70 0.74 nmol/mg protein per 60 min between dietary levels of 4 5 and 5.0 g methionine plus cystine/kg DM. The activity then increased to a maximum value of 2.32 nmol/mgprotein per 60 min at the 6.0 g/kg DM level. Thereafter the activity decreased, reaching a minimum value of 0.70 nmol/mg protein per 60 min at the 7.0 g methionine plus cystine/kg level.6. Urinary urea-N excretion decreased significantly from 1.07 g/kg DM intake at the 4.5 g dietary meth- ionine plus cystine/kg DM level to 1.05g/kg DM at the 5.0 g/kg dietary level, then dropped significantly to a level of 1.01–1.00/kg DM intake for the higher levels of dietary methionine plus cystine.
The effect on plasma lipids of the isoenergetic replacement of table sucrose by dried glucose syrup (maize-syrup solids) in the normal diet of adult men over a period of 1 year
Authors: Lock Susan , Ford M. A. , Bagley R. , Green L. F. 
Published: June 2005

1. Eighteen males (31–62 years) who habitually consumed significant amounts of table sucrose (approximately 25% of total carbohydrate intake) were supplied with their usual intake of sucrose for consumption in conjunction with their normal diet for 1 year, and a record kept of the amount consumed. The sucrose was then replaced isoenergetically by dried glucose syrup (55 D. E.) which contained saccharin to equate the sweetness to that of sucrose.2. Fasting blood samples were taken every 4 weeks during the 2 years, and the plasma analysed for glucose, cholesterol, triglycerides and phospholipid-P by automated colorimetric methods. Dietary questionnaries were issued every 3 months to confirm that subjects were not substantially altering their diets.3. In subjects whose weight remained unchanged and in those who lost weight there was a significant fall in cholesterol (P< 0.025) and phospholipid (P< 0.025) in the glucose-syrup period compared with the sucrose period; triglycerides did not change. In subjects who gained weight there was a significant increase in triglycerides (P< 0.05), but no change in cholesterol; phospholipid-P fell significantly (P< 0.0005).4. The dietary modification in this experiment was sufficiently long to ensure that subjects had adapted, and the results obtained show stable changes in blood lipids which may be attributed to the isoenergetic replacement of table sucrose by glucose syrup.
Metabolic effects of altering the 24 h energy intake in man, using direct and indirect calorimetry
Authors: Dauncey M. J. 
Published: June 2005

1. The metabolic effects of increasing or decreasing the usual energy intake for only 1 d were assessed in eight adult volunteers. Each subject lived for 28 h in a whole-body calorimeter at 26° on three separate occasions of high, medium or low energy intake. Intakes (mean±SEM) of 13830 ± 475 (high), 8400 ± 510 (medium) and 3700 ± 359 (low) kJ/24 h were eaten in three meals of identical nutrient composition.2. Energy expenditure was measured continuously by two methods: direct calorimetry, as total heat loss partitioned into its evaporative and sensible components; and indirect calorimetry, as heat production calculated from oxygen consumption and carbon dioxide production. For the twenty-four sessions there was a mean difference of only 1.2 ± 0.14 (SEM)% between the two estimates of 24 h energy expenditure, with heat loss being less than heat production. Since experimental error was involved in both estimates it would be wrong to ascribe greater accuracy to either one of the measures of energy expenditure.3. Despite the wide variation in the metabolic responses of the subjects to over-eating and under-eating, in comparison with the medium intake the 24 h heat production increased significantly by 10% on the high intake and decreased by 6% on the low intake. Mean (± SEM) values for 24 h heat production were 8770 ± 288, 7896 ± 297 and 7495 ± 253 kJ on the high, medium and low intakes respectively. The effects of over-eating were greatest at night and the resting metabolic rate remained elevated by 12% 14 h after the last meal. By contrast, during under-eating the metabolic rate at night decreased by only 1%.4. Evaporative heat loss accounted for an average of 25% of the total heat loss at each level of intake. Changes in evaporative heat loss were +14% on the high intake and −10% on the low intake. Sensible heat loss altered by +9% and −5% on the high and low intakes respectively.5. It is concluded that (a) the effects on 24 h energy expenditure of over-feeding for only 1 d do not differ markedly from those estimated by some other workers after several weeks of increasing the energy intake; (b) the resting metabolic rate, measured at least 14 h after the last meal, can be affected by the previous day's energy intake; (c) the zone of ambient temperature within which metabolism is minimal is probably altered by the level of energy intake.
Iron absorption from maize (Zea mays) and sorghum (Sorghum vulgare) beer
Authors: Derman D. P. , Bothwell T. H. , Torrance J. D. , Bezwoda W.R. , Macphail A. P. , Kew M. C. , Sayers M. H. , Disler P. B. , Charlton R. W. 
Published: June 2005

1. Iron absorption from maize (Zea mays) and sorghum (Sorghum vulgore) beer was more than twelvefold greater than from a gruel made from the constituents used to prepare the beer.2. The effect of changes occurring during brewing were investigated. These changes include a decrease in the solid content, and the formation of 30 ml ethanol/l and 5 ml lactic acid/].3. The presence of solid material was found to inhibit Fe absorption markedly, especially when the solid content was 100 g/l or more.4. The presence of ethanol potentiated Fe absorption but the effect was only modest in gruels with a high solid content.5 Fe absorption from a 2 ml lactic acid/] solution was four-fold greater than from a hydrochloric acid solution of the same pH. When lactic acid was added to a gruel containing 200 8 solids/l the mean absorbtion rose from 0.4 to 1.2%.6. In a direct comparison, Fe absorption from beer was significantly better than from a gruel of similar pH containing lactic acid.7. The results suggest that at least three factors are responsible for the enhanced Fe absorption from maize and sorghum beer. These include the removal of solids during fermentation and the presence of ethanol and of lactic acid in the final brew.8. In order to reproduce the way in which beer is brewed domestically in Fe containers, a study was done in which beer was prepared in the presence of Fe wire. Under such circumstances Fe was rapidly dissolved and the final Fe concentration of the brew was 89 mg/l. However, the nature of the Fecontaining compound or compounds was not elucidated.
Carbohydrate utilization in obese subjects after an oral load of 100 g naturally-labelled [13C] glucose
Authors: Ravussin E. , Doerner Annelise , Acheson K. J. , Pahud P. , Arnaud M. J. , Jéquier E. 
Published: June 2005

1. Total carbohydrate (CHO) and ingested glucose oxidation was measured in five obese subjects with normal glucose tolerance after an oral load of 100g naturally-labelled [13C]glucose using indirect calorimetry and mass spectrometry respectively.2. CHO utilization rate (107 ± 14 mg/min in the post-absorptive state) increased 30 min after the glucose load to reach a plateau (245±25 mg/min) between 90 and 120 min. It then decreased to basal values at 330 min. Cumulative CHO oxidation over 480 min was 66±7 g and the CHO oxidized above basal levels was 26 ± 7g.3. Enrichment of expired carbon dioxide with13c began at 45 min and maximum values were observed between 210 and 300 min. At 480 min, cumulative oxidation of the ingested glucose was 24± 2 g.4. Compared with controls, the obese subjects exhibit an impairment of CHO utilization which precedes glucose intolerance. This impairment can be explained by an increased availability of free fatty acids which favours lipid oxidation at the expense of ingested [13C]glucose oxidation.
Energy and protein nutrition of early-weaned pigs. 1. effect of energy intake and energy: protein on growth, efficiency and nitrogen utilization of pigs between 8–32 d
Authors: McCracken K. J. , Eddie S. M. , Stevenson W. G. 
Published: June 2005

1. The effect of energy and protein intake on the growth, food efficiency and nitrogen retention of artificially-reared pigs was studied over three 8 d periods between 8–32 d of age in an experiment employing a 5×3×2 factorial design. The factors were initial energy: N value (I; 250, 355, 460, 565 or 670 kJ/g N), rate of increase of 1 at 8 d intervals (0, 12.5 or 25%) and plane of nutrition (three times daily to appetite or 75% of this intake).2. The range of energy: N values was obtained by formulating five diets based on dried skim milk, lactose and casein and feeding appropriate combinations of two diets. The diets, which were pelleted, contained 100 g maize oil/kg and the gross energy content was approximately 20 MJ/kg.3. N digestibility was high at all three age intervals, reaching 0.99 on the diet containing the highest dietary crude protein (N × 6.25) level. Metabolic faecal N excretion was found to be 1.1 g/kg dry matter (DM) intake.4. Growth rate, feed conversion ratio (kg food intake/kg wt gain; FCR), N retention (NR) and the proportion of digested N retained (NR:apparent digested N (ADN)) were significantly (P< 0.001) affected by I values at all age intervals and the responses were quadratic. Response curves were calculated by the least squares method and optimum values of I determined for each of the criteria.A constant energy:N value of approximately 400 kJ/g N was indicated by growth, FCR and NR optima but the NR:ADN value fell from 0.77 for the 8–16 d period to 0.60 for the 24–32 d period at this I value. It is concluded that a suitable compromise would be an I value of 470 kJ/g N increasing by 10%/week.5. There was a significant interaction between plane of nutrition and I values on FCR between 16–24 d (P< 0.001) and 8–32 d (P< 0.01) indicating that FCR was better at high protein levels and worse at low protein levels when the diets were fed on the lower plane of nutrition.
Energy and protein nutrition of early-weaned pigs. 2. effect of energy intake and energy: protein on energy utilisation and body composition of pigs slaughtered at 32 d
Authors: McCracken K. J. , Eddie S. M. , Stevenson W. G. 
Published: June 2005

1. The effect of energy and protein intake on the nitrogen and energy utilization and carcass composition of artificially-reared pigs was studied between 8 and 32 d of age in an experiment employing a 5 × 3 × 2 factorial design. The factors were initially energy:N value (I) (250, 355, 460, 565 or 670 kJ/g N), rate of increase of I (R) at 8 d intervals (0, 12.5 or 25%) and plane of nutrition (three times daily to appetite or 75% of this intake).2. The range of energy:N values was obtained by formulating five diets based on dried skim milk, lactose and casein and feeding appropriate combinations of two diets.3. The metabolizable energy (ME) intake, carcass dry matter (DM) content, carcass protein gain and carcass fat gain exhibited significant (P < 0.001) quadratic responses to I.4. The carcass fat content in the DM increased from 200 to 342 g/kg (P < 0.001) and the carcass crude protein (N × 6.25) content decreased from 657 to 519 g/kg with increasing level of I (P < 0.001). The fat and protein contents were 309 and 556 g/kg and 242 and 610 g/kg respectively on the high and low plane of nutrition (PN) and were significantly different (P < 0.001).5. There was a significant I × R interaction in relation to carcass protein gain with the maximum gain occurring at 460 kJ/g N when I was constant and at 355 kJ/g N when R was 25% per 8 d.6. The proportion of apparent digested N intake retained (N retention (NR): apparent digested N (ADN)) was significantly (P < 0.001) affected by all three factors and there were significant I × R (P < 0.001), I × PN (P < 0.01) and R × R × PN (P < 0.01) interactions. The maximum value of NR:ADN was 0.80.7. Carcass fat gain and carcass energy gain exhibited quadratic responses to I reaching maximum values at 460 kJ/g N. The energy content of the live-weight gain increased linearly (P < 0.001) from 5.79 to 7.90 MJ/kg with increasing level of I. PN and R also produced significant (P < 0.001) responses the means being respectively 7.52 and 6.39 MJ/kg on the high and low PN and 6.55, 6.94 and 7.38 kJ/kg with increasing value of R.8. Multiple regression analysis of ME intake on live-weight (W), protein gain (PG) and fat gain (FG) yielded the equation: <m:math><m:mrow><m:mtext>ME</m:mtext><m:mo stretchy="false">(</m:mo><m:mtext>MJ</m:mtext><m:mo stretchy="false">)</m:mo><m:mo>=</m:mo><m:mn>0</m:mn><m:mo>.</m:mo><m:mn>644</m:mn><m:msup><m:mtext>W</m:mtext><m:mrow><m:mn>0</m:mn><m:mo>.</m:mo><m:mn>75</m:mn></m:mrow></m:msup></m:mrow><m:mo>+</m:mo><m:mn>32</m:mn><m:mo>.</m:mo><m:mn>6</m:mn><m:mtext>PG</m:mtext><m:mo>+</m:mo><m:mn>48</m:mn><m:mo>.</m:mo><m:mn>2</m:mn><m:mtext>FG</m:mtext><m:mo>.</m:mo></m:math>This result is discussed in relation to published values for the energy requirements of the young pig.
A method for determination of unoxidized and total methionine in protein concentrates, with special reference to fish meals
Authors: Njaa L. R. 
Published: June 2005

1. An automated colorimetric method for determination of methionine using an iodoplatinate reagent is described. Methionine sulphoxide does not react under the chosen conditions.2. The method may be used to distinguish between unoxidized and total methionine by doing one deter- mination without and one determination with previous reduction of a portion of the sample with titanium trichloride. Methionine sulphoxide is then obtained by difference.3. The method has been used with protein concentrates, mainly fish meals, after hydrolysis with barium hydroxide. Interference from cysteine-cystine is eliminated by adding a small amount of cadmium acetate to the sample before hydrolysis.4. Results obtained for total methionine and for methionine sulphoxide by independent methods show good agreement with results obtained with the iodoplatinate method.
Tryptophan and the control of triglyceride and carbohydrate metabolism in the rat
Authors: Fears R. , Murrellt Elspeth A. 
Published: June 2005

1. Hepatic fatty acid synthesis, measured in vivo using8H2O, was increased by a single dose of L-tryptophan (50 mg/kg body-weight) to both fed and fasted rats and by a supplement of tryptophan to the diet (2.5 g/kg diet for 7 d) when the rats were killed midway through the feeding period.2. Additional dietary tryptophan was hypotriglyceridaemic in normal rats but exacerbated the hyper- triglyceridaemia in rats when lipoprotein clearance was impaired 24 h after an injection of Triton WR 1339 (Chromatography Services Co., Birkenhead, Cheshire).3. The effects of tryptophan on hepatic fatty acid synthesis and the concentration of serum triglyceride were not directly related to the action of the amino acid on gluconeogenesis. A lack of correlation between inhibition of gluconeogenesis and enhancement of lipogenesis was confirmed using mercaptopicolinic acid, a specific inhibitor of phosphoenolpyruvate carboxykinase (EC4.1.1.32).4. DL-Tryptophan itself did not provide a significant contribution of substrate to the total rate of lipogenesis. Other possible explanations for the activity of tryptophan noted in the present experiments are discussed.5. In conclusion, moderate intakes of tryptophan affect fatty acid and triglyceride metabolism under physiological conditions and it is proposed that the amino acid may be involved in the control of lipid metabolism in a variety of metabolic states.
Seasonal changes in plasma retinol-binding holoprotein concentration in japanese quail (Conturnix coturnix japonica)
Authors: Glover J. , Heaf D. J. , Large Suzanne 
Published: June 2005

1. Seasonal changes in retinol-binding holoprotein (holoRBP) concentration in plasma of group of male and female Japanese quail (Coturnix coturnix japonica) were examined over 18 months.2. In Expts 1 and 2 the birds were maintained under natural lighting conditions and in Expt 3 under artificial-light photoperiods corresponding to the changing daylength at 56° N latitude. All groups were at 18–20° and received Superlayers' (Rank Hovis McDougall) pellet diet.3. The mean plasma holoRBP concentration in all groups changed in an annual cycle with minimal values in September–October and maximal values in February–April, when daylength or light photoperiod increased to more than 10 h.4. The group mean values in the female cycle change 2- to 3-fold from 50–100 μg/ml in late summer to 220–280 μg/ml in the spring, whereas in the male the range is only 1.3–1.5 times, from 140–170 to 180–250 μg/ml.5. In the female the rate of egg laying was maximal in April–May and lowest in November–December.6. The spring increase in plasma holoRBP reflects the increased vitamin A requirement of birds for reproduction and it is presumably under hormonal control. The wider amplitude in the female cycle compared with the male probably arises from the additional demand for the transfer of vitamin A into the eggs and hence the need for a higher initial secretion rate from the female liver to meet it.
Levels of polyunsaturated fatty acids in lymphocytes of rats fed on diets varying in polyunsaturated fatty acid content
Authors: Tsagn W. M. , Belin J. , Smith A. D. 
Published: June 2005

1. When weanling rats were fed on a diet containing 0.1 g/kg of the diet as polyunsaturated fatty acid, it was found that after 2 weeks the level of linoleate in the lymphocyte total lipids was 56 mg/ g total fatty acids, as compared with a level of 138 mg/ g in rats on a normal diet (P< 0.005). Similar levels were obtained from rats which had been fed for up to 16 weeks on the deficient diet, but in a group killed after 28 weeks on the diet the level was found to be only 20 mg/ g total fatty acids. The arachidonate level was found to be approximately 220 mg/ g total fatty acids, regardless of whether the rats were fed on a diet deficient in linoleate for up to 16 weeks or on a normal diet. In the group of rats killed after 28 weeks on the linoleate deficient diet, however, the arachidonate level was only 60 mg/ g total fatty acids.2. Percentage values for total fatty acids are given for plasma, adipose tissue, and lymphocytes for rats on normal and experimental diets.3. Scatter diagrams of the levels of linoleatev.arachidonate in the lymphocyte total fatty acids showed no correlation between the levels of the two acids (r0.05), but similar plots of linoleate and oleate levels showed an inverse correlation (r– 0.68).
α2HS-glycoprotein serum levels in protein–energy malnutrition
Authors: Schelp F. P. , Thanangkul Ousa , Supawan Venus , Pongpaew Praneet 
Published: June 2005

1. α2HS-glycoprotein accumulates in bone and dentine and its plasma levels could vary in conditions in which the rate of bone formation is altered.2. The plasma concentration of this protein was found to be lower in thirteen children suffering from protein–energy malnutrition compared with age-matched healthy preschool children.3. This finding might be associated with the phenomenon of stunting in protein–energy malnutrition.
The effect of rehabilitation at different stages of development of rats marginally malnourished for ten to twelve generations
Authors: Stewart R. J. C. , Sheppard Hilda , Preece R. , Waterlow J. C. 
Published: June 2005

1. Rats which have been maintained for ten to twelve generations on diets of low protein value were rehabilitated in utero (group P), from birth (group F) and from 4 weeks of age (group W).2. Group W showed little change in physique, behaviour or learning, indicating that for recovery to be effective refeeding must begin earlier.3. Group F just failed to attain full physical recovery (90%) whereas group P overgrew by 18.6% in weight and 8.5%; in length.4. In a test designed to evaluate learning ability rehabilitated rats of groups P and F were significantly less successful than normal rats, but more successful than rats of group W or rats of the original undernourished colony.5. Rehabilitation for a further two generations in groups F and P corrected any residual physical and behavioural defects but produced no further improvement on the Lashley (I 938) jumping platform.
Measurement of chemically-available iron in foods by incubation with human gastric juice in vitro
Authors: Lock Susan , Bender A. E. 
Published: June 2005

1. The proportion of iron liberated from twenty foods was measured after incubation in vitro with human gastric juice.2. Results with samples of gastric juice obtained from one subject on ten occasions and from sixteen subjects on a single occasion showed good agreement, the proportions of Fe liberated covering the entire range from zero for egg to 1.0 for wine.3. Where there were small variations between the results obtained with different samples of gastric juice attempts were made to correlate these with peptic activity, various proteins and mucoproteins, pH and total and free acid; the only factors that varied with the proportions of Fe solubilized were the various measures of acidity.4. The results correlated highly with those of Layrisse et al. (1969) for the in vivo absorption of Fe from similar foods, although the samples used were not the same.5. The amounts of Fe solubilized when the foods were mixed with bran, oats or egg (known to reduce the in vivo absorption of Fe from foods) were less than calculated from the sum of each, with two exceptions.6. The results obtained with human gastric juice differed from those obtained with in vitro methods prcviously reported, namely treatment with dilute hydrochloric acid and double incubation with pepsin plus HCI at pH 2.5 followed by adjustment to pH 7.5.7. The amount of Fe solubilized from soya-bean flour by gastric juice was compared with that solubilized by pepsin plus HCI; both systems were shown to be pH dependent but the amount of Fe liberated with pepsin- HCI was much greater than that known to be absorbed by man in vivo.8. It is suggested that incubation with human gastric juice may permit in vitro analyses of ‘chemically- available’ Fe in foods and thus be of value in food composition tables in terms of ‘Fe equivalents’ even though the amounts absorbed in vivo are subsequently influenced by other ingredients of the diet and by the Fe status of the individual.