bluuebunny/crossref_metadata_2025 huggingface dataset:
Household food wastage in Britain
Authors: Wenlock R. W. , Buss D. H. , Derry B. J. , Dixon E. J.
Published: June 2005

1. The total food and drink available for human consumption in the United Kingdom would provide approximately 13 MJ (3100 kcal)/person per d, while the energy intake recommended for the population is approximately 9.6 MJ (2300 kcal)/person per d. A proportion of this substantial difference must be due to wastage in the home as well as in catering establishments and during the storage, distribution and processing of food.

2. As part of a general investigation of this problem, a representative sample of 1000 British households was asked to collect all the potentially-edible food wasted in their homes during 1 week, and to keep a record of the food, other than commercial pet food, which they gave to pets and wild birds. A total of 672 households co-operated fully, 338 in summer and 334 in winter. Each food sample received was weighed, and its energy content was determined calorimetrically.

3. Significantly more waste food was collected in summer than in winter, equivalent to 9.3 MJ (2220 kcal)/household per week and 7.1 MJ (1700 kcal)/household per week respectively. In terms of energy, cereals, fat and meat wastage predominated, while in terms of weight, milk was more important and fat less so.

4. Considerable quantities of otherwise edible food were also given to pets and birds, accounting on average for a further 2.4 MJ (570 kcal) and 3.0 MJ (710 kcal)/household per week in summer and winter respectively. The energy content of all food wasted in the home therefore averaged 11.7 MJ (2790 kcal)/household per week in summer and 10.1 MJ (2410 kcal)/household per week in winter, equivalent to 0.6 MJ (150 kcal) and 0.5 MJ (130 kcal)/person per d respectively. This is less than one-quarter of the gap between food supplies and the amount of food thought to be eaten in the UK.

5. Food wastage was significantly influenced by the composition of the family, with adults wasting more in absolute terms than children, and larger households wasting less per person than smaller households. However, with few exceptions, neither income nor geographical region significantly affected the total amount of food wasted in the home.

6. When assessed against the expected usage of food in the home, wastage accounted on average for 6.5% of the energy intake in summer and 5.4% in winter.
Duration of activities and energy expenditure of female farmers in dry and rainy seasons in Upper-Volta
Authors: Bleiberg Fanny M. , Brun Thierry A , Goihman S. , Gouba Emile
Published: June 2005

1.Fifteen female farmers (aged 18–47 years) from two villages of the Mossi Plateau in Upper-Volta participated in a survey in which their daily activity pattern and their energy expenditure were assessed. Eight of the subjects were investigated twice, in March (dry season) when there is no agricultural activity, and in July–August (rainy season) when heavy physical work is performed: mostly hoeing, weeding and replanting sorghum (Sorghum vulgare) and millet (Pennisetum typhoïdes).

2. The mean height was 1.57 m and the mean weight 50.6 kg. The average percentage of body fat, calculated from skinfold thickness, was comparable to that of European females but the triceps skinfold was more than 60% below the standard value (Jelliffe, 1969). The type of activities and the period of time spent on each activity changed significantly with the season. The mean energy output rose from 9.7 MJ (2320 kcal) in March to 12.1 MJ (2890 kcal) in July–August for a 55 kg standard weight.

3. In this paper, the extent of both the dally activity pattern of women living in a subsistence agriculture and their energy output is estimated. The results suggest that during the rainy season, the energy requirements of female farmers are much higher than usually estimated.
Heat loss from humans measured with a direct calorimeter and heat-flow meters
Authors: Close W. H. , Dauncey M. J. , Ingram D. L.
Published: June 2005

1. Heat loss from three men and three women was measured in a direct calorimeter over 2 or 3 h periods and compared with that determined simultaneously from heat-flow meters attached to the skin surface at the waist. The comparisons were made at each of four ambient temperatures, 15, 20, 25 and 30°. Each subject wore a cotton boiler-suit and minimal underwear.

2. Oral temperatures and skin and clothing temperatures on both trunk and forearm were determined, thus enabling the subjects' internal and external insulation to be calculated.

3. Heat loss determined by the meters was lower than that determined by the calorimeter. The difference increased with increase in ambient temperature. ‘Meter’ heat loss decreased linearly as ambient temperature was raised.

4. It was concluded that heat-flow meters could provide a useful estimate of total heat loss when the evaporative component is low. The estimate might be improved if the subject is calibrated while wearing the meters in a calorimeter over several short periods. Heat-flow meters could therefore be of particular value in sedentary individuals, when the heart-rate method for estimating energy expenditure can be inappropriate.
The effect of dietary fibre on bile acid metabolism in rats
Authors: Brydon W. G. , Tadessea K. , Eastwood M. A. , Lawson Margaret E.
Published: June 2005

1. Forty-eight male rats were fed sequentially for 14 d periods on diets containing different fibre contents.

2. One of the high-fibre diets was a commercial pelleted diet. The other was a low-fibre diet supplemented with 200 g wheat bran/kg.

3. At the end of each feeding period eight rats were killed. Liver microsomal cholesterol 7α-hydroxylase (EC 1.14.1.-) activity and bile acid content of small intestine and colon were determined.

4. The different diets did not significantly alter the total intestinal bile acids, but affected the distribution and qualitative pattern in the colon and small intestine.

5. On the high-fibre diets deoxycholate, and hyodeoxycholate tended to be increased.

6. On the low-fibre diets the α-, β- and ω-muricholic acids tended to be increased.

7. Liver microsomal cholesterol 7α-hydroxylase activity was lower in rats fed on the low-fibre and bran- supplemented low-fibre diets compared with that in rats fed on the commercial pelleted diet.
The level and distribution of carbohydrases in the small intestine mucosa of pigs from 3 weeks of age to maturity
Authors: Kidder D. E. , Manners M. J.
Published: June 2005

1. The levels of the brush-border enzymes sucrase (sucrose glucohydrolase,EC3.2.1.48), isomaltase (oligo-1,6-glucosidase,EC3.2.1.10), maltases 2 and 3 (glucoamylase,EC3.2.1.3), lactase (β-galactosidase,EC3.2.1.23) and trehalase (EC3.2.1.28) and adsorbed pancreatic α-amylase (EC3.2.1.1) have been measured at twenty-one positions along the small intestines of eighty-four pigs of different ages ranging from 3 weeks to 4.5 years. The state of dilation of the intestine at the sampling points was noted.

2. The levels of sucrase and isomaltase increased with age throughout the age-range studied. Trehalase and the glucoamylases increased with age up to 200–300 d of age. Lactase decreased with age over the whole age range.

3. For the pigs above 10 weeks of age, the distribution pattern of the brush-border enzymes along the intestine did not change with age. Each enzyme had a characteristic distribution curve, with low values at the proximal and distal ends and a peak which was proximal in the instance of lactase and trehalase and approximately mid-way along the gut with sucrase, isomaltase and the glucoamylases.

4. The pattern of distribution of the brush-border enzymes altered with age in the piglets, but approached the adult pattern by 8 weeks.

5. Piglets weaned at 3 weeks had higher levels of sucrase, isomaltase and glucoamylases at 5 weeks than piglets left on the sow. At 8 weeks of age the piglets weaned at 3 weeks still had higher sucrase and isomaltase levels than those on the sow.

6. There was a very close correlation between the sucrase and isomaltase levels, and between the maltase 2 and maltase 3 levels in all the samples, and a fairly close correlation between all these four enzymes.

7. The level of α-amylase increased with age but showed no regular distribution pattern, its irregular fluctuations being related to the presence or absence of dilation of the intestine at the time of slaughter rather than to the position along the intestine.
Motor activity in the large intestine of the pig related to dietary fibre and retention time
Authors: Fioramonti J. , Bueno L.
Published: June 2005

1. Large intestine electromyograms were recorded from four pigs receiving successively three diets containing different amounts of fibre (standard cereal diet, milk substitute and milk plus 170 g bran/kg). For each diet the mean retention time of a marker added to one meal was determined. Three occurrences of spontaneous constipation were also studied.

2. Slow waves were observed in the colon only during 10% of the recording time at a frequency of 10.3 ± 1.1/min. Two kinds of spiking activity were recorded on the colon: short spike bursts of 0.5–2 s duration and long spike bursts of approximately 7 s duration. Long spike bursts alone were recorded on the caecum.

3. The mean retention time of the marker was 40 h on the standard diet, 120 h on the milk-substitute diet, and 66 h on the milk plus bran diet.

4. On the standard diet, approximately 1500 colonic long spike bursts were recorded daily and short spike bursts occupied 15% of the recording time. On the milk diet, the number of long spike bursts decreased significantly (P < 0.01) to 500/d and the short spike bursts increased significantly (P < 0.05) to take up to 21% of the time. Intermediate values (1100/d and 19%) were observed when bran was added to the milk diet. The lowest values for long spike bursts (300/d) and highest values for short spike bursts (44% of the time) were observed in constipation.

5. It is concluded that long spike bursts are associated with propulsion of intestinal contents and that short spike bursts are non-propulsive.
Studies on the absorption of zinc by rat intestine
Authors: Davies N. T.
Published: June 2005

1. A technique is described for the measurement of the extent of65Zn absorption by different regions of the intestine in the intact rat. Using this technique it was shown that the duodenum contributed 60%, the ileum 30% and the jejunum 10% to the over-all absorption of65Zn. Negligible absorption of65Zn occurred from the caecum and colon.

2. Using ligated loops of rat duodenumin situ,65Zn absorption was shown to be rapid, with 1% of a 5 μg dose being transferred to the carcase within 1 min of intraluminal dosing.

3. When65Zn was injected into ligated loops in a dose range of 1–200 μg Zn/ml the rate of absorpion was linear with respect to time over the first 15 min. The rates of65Zn absorptionv.dose of65Zn exhibited saturation kinetics indicating absorpion by a ‘carrier’ or enzyme-mediated process.

4. The binding of65Zn to loop tissue showed biphasic kinetics which suggested that at low intraluminal concentrations of Zn (1–50 μg Zn/ml) binding was to specific sites whereas, at higher concentrations (50–200 μg Zn/ml), non-specific binding occurred.

5. A study of the fate of mucosally bound65Zn showed that over the first 30 min a proportion of the65Zn was rapidly transferred to the carcase and this was probably associated with the rapid phase of65Zn absorption described previously. From 30 min up to 6 h after the initial binding,65Zn was also transferred to the carcase albeit at a much slower rate indicating a slow phase of Zn absorption. A study of the kinetics of this slow phase indicated that the loss of bound65Zn to the body was a saturable process indicating an enzyme or ‘carrier’-mediated process. A comparison of the kinetics of the slow and rapid phases of65Zn absorption suggests that these processes are distinct.

6. Histological examination of mucosal tissue of loops exposed to 200 μg Zn/ml revealed no discernable damage. Similarly, no effect was observed on either arginine or glucose uptake by isolated duodenal loopsin situ, although this concentration of Zn completely abolished fluid uptake. A study of the effect of different doses of Zn showed that 50 μg Zn/ml inhibited mucosal fluid uptake by more than 50% and 100 μg Zn/ml by more than 90%. It was concluded that these effects were due to a specific action on the fluid-transfer process and not due to a general poisoning of the mucosa.
Effects of level of dietary copper sulphate and period of feeding on the laying, domestic fowl, with special reference to tissue mineral content
Authors: Stevenson Mary H. , Jackson N.
Published: June 2005

1. A cereal-based diet containing 7.6 mg copper/kg was fedad lib. to laying hens for up to 48 d. Four other groups were given the control diet to which was added hydrated copper sulphate to provide 250, 500, 1000 and 2000 mg added Cu/kg.

2. Hens were killed on day o and after 3, 6, 12, 24 and 48 d. Records were kept of body-weight, food consumption, egg production and egg weight.

3. After slaughter blood haemoglobin, packed cell volume, serum Cu and aspartate aminotransfferase- (AAT; EC 2.6. I. I) were measured. The liver, kidneys, a sample of breast muscle, oviduct, ovary and gizzard were weighed. Gizzard, spleen. liver and kidney tissue were examined histologically.

4. The Cu, zinc and iron concentrations of liver, kidneys and breast muscle and the manganese concentrations of liver and kidneys were determined.

5. Body-weight loss occurred at 500–2000mg added Cu/kg diet. Egg production was depressed by level of added Cu and period of time on the Cu-containing diets.

6. Mean liver, kidney, oviduct and ovarian weights per unit body-weight were depressed by Cu in the diet and the effect increased with period of time on the diets. Mean gizzard weight per unit body-weight was increased by dietary added Cu and by time.

7. Cu concentrations in the liver were increased by dietary level of added Cu and period of timeon the diet. Zn concentration in liver increased at 1000 and 2000 mg added Cu/kg diet and liver Fe concentration was increased at these levels. Histological examination of the gizzard indicated that the Cu content of the gizzard lining increased with dietary added Cu.
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.
A novel estimate of the magnitude of heat produced in the rumen
Authors: Czerkawski J. W.
Published: June 2005

Using a well-known equation relating the heat production to the respiratory measurements, the total heat produced in the animal is partitioned into heat produced in the rumen and heat produced in the body. It is shown that the values of the partition constants can be calculated by making two simple logical deductions. Consideration of known heats of fermentation of carbohydrate and protein shows that the deductions are justified.
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: ME(MJ)=0.644W0.75+32.6PG+48.2FG.

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.
Rumen bacterial protein synthesis and the proportion of dietary protein escaping degradation in the rumen of sheep
Authors: Mercer J. R. , Allen Sarah A. , Miller E. L.
Published: June 2005

1. The effect of supplementing barley diets with urea (U), extracted, decorticated groundnut meal (GNM) or Peruvian fish meal (PFM) on rumen bacterial protein synthesis and the proportion of undegraded food protein passing to the duodenum of sheep has been examined.

2. Three wethers were given isonitrogenous, isoenergetic diets containing (g/kg dry matter (DM)): U 20, GNM 106 or PFM 78, the crude protein (nitrogen × 6.25) contents being 139, 145 and 148 respectively. The sheep were fed hourly, the mean daily intake of DM being 0.634 kg.

3. Rumen bacterial protein synthesis was determined using35S and diaminopimelic acid (DAPA) as bacterial markers and polyethylene glycol (PEG) and chromic oxide as markers of digesta flow. Rumen volatile fatty acid (VFA) production rate was determined by a continuous infusion of [I-14C]acetate. 4. and DAPA gave similar estimates of the proportion of bacterial N in the trichloroacetic acid- precipitable nitrogen of the rumen digesta, the mean value being 0.86. The VFA production rate did not vary significantly between diets, the mean being 5.8 mol/24 h. The flow of bacterial N from the rumen was calculated from the PEG and Cr2O3, estimates of flow and the35S and DAPA estimates of the proportion of bacterial N in the rumen. and DAPA gave similar values (mean 12.5 g/24 h) and Cr2O3, gave a slightly lower value (11.5 g/24 h) than PEG (13.5 g/24 h). Dietary effects, averaged over the four methods, were not significant; the values were 13.0, 13.4 and I 1–0 g/24 h for the U, GNM and PFM diets respectively.

5. Duodenal samples were taken from two 12h continuous collections from re-entrant cannulas and the DM flow adjusted to total recovery of Cr2O3,. The mean recovery of Cr203at the duodenum was 0.798. The rates of flow of DM were 0.296,0.311 and 0.334 kg/24 h and of non-ammonia-N (NAN) 13.5, 15.2 and 15.4 g/24 h on the U, GNM and PFM diets respectively.

6. The concentrationsof the essential amino acids in duodenal digestaweregenerally higher with the PFM diet than with either of the other two diets. The flow of most amino acids through the duodenum was generally higher on the PFM and GNM diets than on the U diet.

7. The energetic efficiency of bacterial protein synthesis was calculated to be 2.1 g bacterial N/mol VFA or 28 g bacterial N/kg organic matter fermented in the rumen.

8. From the estimates of bacterial N flow from the rumen and NAN flow through the duodenum it was calculated that 0.22 and 0.69 of the supplemental N from GNM and PFM respectively passed through the rumen undegraded.
The validity of assessing changes in intestinal absorption mechanisms for dietary sugars with non-metabolizable analogues (glucalogues)
Authors: Syme Gabrielle , Levin R. J.
Published: June 2005

1. Transfer potentials were obtained from everted jejunal sacs prepared from fed euthyroid, fasted euthyroid, fed hypothyroid and fasted hypothyroid rats by addition of serial concentrations of the dietary sugars glucose and galactose and the glucalogues 3-O-methyl glucose, α-methyl glucoside and 6-deoxy-D-glucose to the incubation fluids. The kinetic parameters of ‘apparent Michaelis constant’ (apparent Km) and maximum transfer potential difference (pdmax) obtained from the results were used to characterize the changes in the electrogenic transfer mechanisms for these substrates.

2. Analysis of the significant differential changes in values for ‘apparent Km’ and pdmax for the two dietary sugars and the three glucalogues indicated heterogeneity in the mechanisms for sugar transfer across the intestine and suggested a minimum of four possible carriers.

3. The validity of using glucalogues to characterize changes in the transfer mechanisms for the dietary sugars in different dietary and hormonal states was assessed. None of the kinetic parameters for electrogenic glucalogue transfer matched those for the dietary sugars in all the experimental conditions. The employment of glucalogues to assess changes in electrogenic transfer mechanisms for dietary sugars can thus lead to invalid conclusions.

4. Fasting decreased the ‘apparent Km’ of the dietary sugars and the glucalogues. However, the pdmax values for glucose, galactose, and α-methyl glucoside decreased whereas those for 3-O-methyl glucose and 6-deoxy-D-glucose did not.

5. Hypothyroidism showed different effects in fed and fasted intestine. Because hypothyroidism induced a reduction in food intake, separation of the direct effects of the condition on electrogenic transfer from reduced food intake effects was not possible.
Protein turnover in growing pigs. Effects of age and food intake
Authors: Reeds P. J. , Cadenhead A. , Fuller M. F. , Lobley G. E. , McDonald J. D.
Published: June 2005

1. Measurements were made of the nitrogen and energy balances of pigs of 30, 60 and 90 kg given a conventional diet at various daily rates.

2. Body protein synthesis was estimated from the irreversible loss of leucine from the blood following the infusion of [1-14C]leucine, and from the oxidation of the labelled amino acid.

3. Protein synthesis (g/d) increased by 2.17 for each 1 g increase in daily protein accretion and by 1.55 for each 1 g increase in daily protein intake.

4. At 30 kg, pigs close to energy equilibrium synthesized 270 g protein daily compared with 406 g and 512 g when their ration supplied twice and three times their maintenance requirement.

5. There was a close correlation between the daily urinary excretion of urea + ammonia and total amino acid catabolism estimated from the catabolism of leucine, but the latter underestimated the observed excretion by 2.5 g N/d.

6. The results imply that protein turnover accounts for only a proportion of the heat production associated with protein deposition.
The nutritive value of silages Digestion of nitrogenous constituents in sheep receiving diets of grass silage and grass silage and barley.
Authors: Thomas P. C. , Chamberlain D. G. , Kelly N. C. , Wait M. K.
Published: June 2005

Two experiments were conducted to study the digestion of nitrogenous constituents in the rumen, small intestine and caecum and colon of sheep given diets of grass silage or grass silage and barley. Three silages were used. One was made from first-harvest grass in the spring and the others from regrowth grass cut in either early autumn or late autumn. All were of perennial ryegrass (Lolium perenne) and were preserved with formic acid.

Expt 1 involved a comparison between the spring silage given alone (644 g dry matter (DM)/d) and the spring silage supplemented with barley (151 g DM/d). The intakes (g/d) of total nitrogen for the silage diet and for the supplemented diet were 14.89 and 17.36. Corresponding values (g/d) for N passage were 15.55 and 18.53 (P < 0.01) at the duodenum, 6.01 and 7.09 at the ileum and 5.06 and 5.52 in the faeces. The barley supplement had no significant (P < 0.05) effect on rumen ammonia-N- concentration.

Expt 2 involved a comparison between the two autumn-cut silages each offered at a level of feeding of approximately 700 g DM/d. The intakes (g/d) of total N for the early-cut silage and for the late-cut silage were 21.67 and 15.62 respectively. Corresponding values (g/d) for N passage were 17.10 and 16.96 at the duodenum, 6.65 and 6.80 at the ileum and 4.5 and 5.22 in the faeces. The concentration of NH3-N in the rumen was significantly (P < 0.001) higher with the early-cut silage than with the late-cut silage.

In both experiments the rates of bacterial crude protein (N × 6.25) synthesis in the rumen, estimated using α, ε-diaminopimelic acid as a marker, were low, 142 and 161 g crude protein/kg organic matter apparently digested in the rumen for the spring silage and the spring silage and barley diets respectively, and 68 and 103 g crude protein/kg organic matter apparently digested in the rumen for the early-cut autumn silage and the late-cut autumn silage respectively. For all diets there was a relatively low contribution of bacterial crude protein to the duodenal passage of crude protein and the amounts of individual amino acids ingested in the diets had a marked influence on the amino acids passing to the duodenum and as a consequence on the mixture of amino acids taken up from the small intestine.

The results are discussed in relation to the nutritive value of silage N for ruminants.