bluuebunny/crossref_metadata_2025 huggingface dataset:
Volatile fatty acid production in the rumen of cattle given an all-concentrate diet
Authors: Whitelaw F. G. , Hyldgaard-Jensen J. , Reid R. S. , Kay Moird G.
Published: May 2005

1. Short-term in vitro incubations of whole rumen contents have been used to measure the rate of production of volatile fatty acids (VFA) in two heifers given a diet containing 85% barley and 15% protein-mineral-vitamin supplement. Daily intake of the diet was restricted to 5.1 kg which was given in three equal feeds. In one heifer (no. 794), VFA production was measured over a 24 h feeding cycle; in the other (no. 832), a single 6 h feeding period was examined.

2. The feeding schedule outlined above was found in previous work to result in a major alteration in the rumen environment and in the end-products of rumen fermentation relative to findings in animals given the same diet ad lib. Some of these earlier observations have been confirmed and extended in the present work.

3. In heifer 794, the rate of VFA production reached a maximum (52–62 m-moles/l. h) 15 minafter each feed and then declined steadily throughout the remainder of the feeding period. Consistent changes with time were observed in rumen pH and in the concentration of VFA and dry matter in rumen contents during each feeding period.

4. Simultaneous measurements of rumen fluid volume and outflow allowed estimates to be made of VFA production and absorption in the entire rumen during each feeding period. In heifer 794, total VFA production amounted to 18.2 moles/day of which approximately 85 % was absorbed directly from the reticulo-rumen. On a caloric basis, total daily production accounted for 36. 5% of the digestible energy intake.

5. In heifer 832 there were significant differences in the rate of VFA production and in rumen pH and VFA concentration between two sets of observations made some 8 weeks apart. These differences appeared to be related to changes in the rumen microbial population and particular to a marked alteration in the numbers of ciliate protozoa. The possible role of rumen ciliates in modifying both the rate of VFA production and the environment within the rumen is discussed.
Studies on intestinal digestion in the sheep
Authors: Pfeffer E. , Thompson A. , Armstrong D. C.
Published: May 2005

1. In each of three experiments, two sheep were given diets consisting of hay, or two parts hay to one part barley or one part hay to two parts barley. Each sheep was equipped with a cannula into the rumen and re-entrant cannulas into the proximal duodenum and the terminal ileum. The rations containing barley were supplemented to adjust the intake of calcium, phosphorus, magnesium, sodium and potassium to a level similar to that in the all-hay ration. Paper impregnated with chromic oxide (Cr2O3) was given twice daily by rumen fistula.

2. Amounts of crude ash and the five minerals entering and leaving the small intestine and excreted in the faeces were measured. The amounts passing through the re-entrant cannulas were adjusted to give 100% recovery of chromic oxide. The values were used to calculate the direction and net movements of the elements through the walls of the three main parts of the alimentary tract.

3. In all instances there was an extensive net secretion of Na and P between mouth and small intestine, net absorption of K and P from the small intestine and of Na from the large intestine.

4. The net movements of Ca and Mg were small and rather variable. In five of the six observations there was a small net secretion of Ca and small net absorption of Mg during passage of the digesta through the reticulo-rurnen, omasurn and abomasurn. Net secretion of Ca and Mg apparently occurred in the small intestine and net absorption of Mg in the large intestine.

5. The only between-diet differences were small differences in net movements of Na and K.
Studies on total body potassium in malnourished infants Factors affecting potassium repletion
Authors: Alleyne G. A. O.
Published: May 2005

1. Serial measurements of total body potassium were made in children while they were malnourished and as they recovered. Initially, there was a low total body potassium which rose slowly and reached the normal levels of 45 m-equiv./kg at 3–4 weeks after admission to hospital.

2. The early stages of recovery were divided into three phases. In the first 5 days of treatment, retention of potassium served to correct a true potassium deficiency and the amount of potassium retained during this phase was related to the initial level of total body potassium. There was no relationship between serum potassium and total body potassium. There was indirect evidence that antecedent diarrhoea was an important factor in the production of potassium depletion.

3. In the next phase—the lag phase—potassium was retained in relation to deposition of new body tissue.

4. In the phase of rapid growth, potassium was also retained in the amount appropriate for deposition of new tissue.

5. After the repair of the acute potassium depletion, potassium retention was always correlated with the protein intake.
A comparison of the effects of raw and heated soya-bean meal in diets for germ-free and conventional chicks
Authors: Coates Marie E. , Hewitt D. , Golob P.
Published: May 2005

1. Chicks were reared to 3 weeks in a germ-free or conventional environment on diets containing 50% raw or heated soya-bean meal. Body-weights and pancreas weights were determined and the proteolytic and amylolytic enzymes in the pancreas were measured. In one experiment the contents of the intestinal tract were analysed for their content of nitrogenous compounds.

2. The growth of chicks given raw soya was depressed below that of controls given heated soya, and the growth depression was significantly greater in the conventional compared with the germ-free environment.

3. The pancreases of chicks given raw soya were significantly larger than those given heated soya. The degree of enlargement was similar in both environments. The concentration of α-amylase was lower in the enlarged pancreases, but the total amount per pancreas was similar to that in the normal pancreases. Conversely, the concentration of proteolytic enzymes was the same or greater in the enlarged pancreases, which had significantly greater total content of proteases than did the normal pancreases.

4. There was evidence of impaired protein digestion in the birds given the raw soya diets. Their gut contents contained larger amounts of insoluble matter, with higher nitrogen content, and the soluble fraction contained more nitrogen present as ‘protein’, with correspondingly less ‘peptide’ and ‘amino acid’, than did similar samples from birds given heated soya. No differences were observed in this respect between germ-free and conventional birds.

5. It was concluded that the gut microflora exacerbated the growth-depressing effect on chicks of raw soya meal. Possible explanations are advanced.
The digestion and absorption of protein in man
Authors: Nixon S. Elizabeth , Mawer G. E.
Published: May 2005

1. The absorption of the amino acid components of two protein-containing test meals has been studied in six healthy volunteers. One meal contained 15 g of milk protein and the other contained 15 g of gelatin. In a control experiment a meal was given which contained a negligible amount of protein.

2. The subjects were intubated with a single lumen tube; then each meal was swallowed and intestinal residues were obtained from known levels. The amino acid composition of the intestinal contents was compared with that of the original meal. Correction was made for net water shifts by reference to a non-absorbable marker compound (polyethylene glycol 4000).

3. The results showed that at least 70–75% of the milk protein test meal had been absorbed when the sampling holes were 230 cm from the nose. It is suggested, however, that most, if not all, of the meal had been absorbed when the sampling holes were 140 cm from the nose.

4. Amino acids were absorbed at rates proportional to their concentrations in the meal.

5. Gelatin, a protein known to be relatively resistant to enzymic hydrolysis, was poorly absorbed from the region of the small intestine under study.

6. Estimates of the amount of endogenous protein secreted in response to the test meals ranged from z to 8 g, equivalent to 13–53% of the protein containing test meals.

7. The absorption of certain amino acids, e.g. the dicarboxylic amino acids, was more rapid than was expected; glutamic and aspartic acids are absorbed slowly from a mixture of amino acids, both in vitro and in vivo.
The digestion and absorption of protein in man
Authors: Nixon S. Elizabeth , Mawer G. E.
Published: May 2005

1. Intestinal contents, collected from the human jejunum after a test meal (milk-protein, gelatin or low-protein) were fractionated by centrifugation and gel filtration on G-75Sephadex. The fractions were hydrolysed and the proportion of the total amino acid in each fraction was determined. The amino acids were measured with an EEL Amino Acid Analyser.

2. The free amino acid concentrations were determined in samples of the contents of the small intestine collected from various levels after the three types of test meal.

3. Intestinal contents collected from two levels of the jejunum after a milk-protein meal, were incubated in vitro at 37° for periods up to 80 min and the rates of release of the individual free amino acids were determined.

4. There was a rapid breakdown of the proteins of the test meals to fragments of molecular weight under 5000. The further breakdown (during incubation in vitro) to free amino acids was sufficiently rapid to account for the absorption in the free form of arginine, lysine, tyrosine, valine, phenylalanine, methionine and leucine. It was not rapid enough to account for the absorption of glycine, threonine, serine, the imino acids or the dicarboxylic amino acids in the free form.

5. The free amino acid concentrations in the intestinal lumen bore very little relationship to the concentrations in hydrolysates of the test meals or to those in hydrolysates of the intestinal contents. Many of the free amino acids in the intestinal samples were present in approximately equimolar concentrations.

6. It is suggested that experiments in which amino acid mixtures, simulating a dietary protein, are fed to experimental animals to determine the rates of amino acid absorption do not present a true picture of the events in the small intestine following the ingestion of a protein meal.
Metabolism of riboflavine in germ-free and conventional rabbits
Authors: Owen E. C. , West D. W. , Coates Marie E.
Published: May 2005

1. Isoalloxazines were characterized and measured in the caecum of two conventional rabbits kept on an adequate diet, two rabbits on the same diet from which vitamin B2 (ribo-flavine) had been omitted and five germ-free rabbits which were also on the adequate diet.

2. Riboflavine (up to 12mg) unaccompanied by any of its degradation products was found in the caecum of germ-free rabbits and 8–9 μg per ml were found in their urine.

3. Hydroxyethylflavine (4–5 mg) accompanied only by traces of riboflavine was found in the caecum of conventional rabbits.

4. There was about 1% ash in the contents of each of five germ-free and two conventional caecums.

5. The five germ-free caecal contents averaged 22.4% of the animal's body-weight. For four conventional animals this figure was only 10.5%.

6. In the caecum of each of two conventional rabbits kept on a diet deficient in riboflavine neither riboflavine nor hydroxyethylflavine was found but there was somewhat less than 1 mg of a yellow-fluorescing material of low RF value in each caecum.

7. The results are discussed in relation to the authors' previous reports on metabolites of riboflavine.
The effects of intravenous infusions of triglycerides on the composition of milk fat in the sow
Authors: Witter R. C. , Spincer J. , Rook J. A. F. , Towers K. G.
Published: May 2005

1. Emulsions with egg phosphatides of nine synthetic triglycerides (tributyrin, tricaprylin, tripelargonin, tricaprin, trilaurin, trimyristin, tripahitin, triisostearin, triolein) and of rapeseed oil and a proprietary emulsion of cottonseed oil were given as continuous infusions into the jugular vein of lactating sows. The effects of the infusions on the concentration and composition of blood plasma lipids and on the composition of milk fat were determined.

2. The infusions did not affect the concentrations in blood plasma of cholesterol, phospholipid or cholesterol esters, but there was a tendency for the concentration of plasma triglycerides to be increased which was most pronounced for the infusions of longer-chain triglycerides. The fatty acid composition of the plasma triglycerides was not altered by the infusion of tributyrin, except that there was an increase in the content of oleic and a decrease in that of linoleic acid. With other infusions the composition of the plasma triglycerides was altered towards that of the infused material and the effect was more marked for the longer-chain triglycerides, with the exception of triisostearin.

3. The changes in the composition of the milk fat reflected those in the composition of plasma triglycerides, with two exceptions. The infusion of tripalmitin was associated with an increase not only in the palmitic acid content of milk fat but also in the palmitoleic acid content. Also, the changes in the content in milk fat of eicosenoic acid and, more especially of erucic acid during the infusion of rapeseed oil were much less than the corresponding changes in the plasma triglycerides.
The complexes of zinc, copper and manganese present in ryegrass
Authors: Bremner I. , Knight A. H.
Published: May 2005

1. The nature of the complexes of zinc, manganese and copper which occur in ryegrass has been examined as part of a study of the availability of these metals to ruminants.

2. Ryegrass labelled with 66Zn was produced by water culture. A large proportion of the Zn could be extracted with aqueous ethanol and with water. The remainder of the Zn was liberated on peptic digestion and on treatment with a fungal cellulase.

3. The aqueous ethanolic extract was examined by a combination of gel filtration and thin-layer chromatographic and electrophoretic techniques. The results showed the presence of closely related complexes of Zn of low molecular weight. These were of limited stability and their behaviour was dependent on pH.

4. The value of electrophoresis in free solution as a fractionation technique for the soluble forms of Cu, Zn and Mn from ryegrass was demonstrated. Soluble Mn from was found to exist in a single cationic, perhaps non-complexed form, whereas several anionic Cu and Zn complexes were present in closely related forms.
The effects of nematode parasitism on the rate of passage of food residues through the alimentary tract of sheep
Authors: Bawden R. J.
Published: May 2005

1. The mean retention time of stained food residues was longer in sheep maintained on a chopped straw ration than in sheep maintained on a chopped lucerne ration.

2. Infection of sheep with 1500 infective Oesophagostomum columbianum juveniles was associated with increased mean retention times.

3. The extent to which the mean retention times were increased was associated with the diet and mode of infection of the sheep.

4. It was noted that an increase in mean retention time following infection was associated with a general decrease in food intake per kg live eight0.75.

5. The results are discussed in relation to the pathogenesis and survival of O.columbianum infections in sheep.
The relationship of diet to serum cholesterol levels in young men in Antarctica
Authors: Easty D. L.
Published: May 2005

1. Regular estimations of dietary intake, body-weight, skinfold thickness, blood pressure and pulse rate, and serum lipids were made in twenty-four members of an Antarctic expedition over 1 year.

2. The mean levels of serum total cholesterol, phospholipids, and triglycerides were 198.5 ±4.85 mg/100 ml, 221.4±5.73 mg/100 ml and 120.9±13.53 mg/100 ml respectively.

3. A positive correlation was found between the total intake of fat expressed as calories and the following serum lipid levels: total cholesterol, β-cholesterol, and the cholesterol:phospholipid ratio. Significant positive correlation was also found between the latter serum levels and fat when expressed as a percentage of the total food intake.

4. This correlation has not been found in small groups before, and is due to the fact that each estimation was the result of several assessments made over 1 year.

5. The survey suggests that the personal serum cholesterol level may be dependent upon the habitual total intake of dietary fat and the percentage of the total calories supplied by fat.
A study of the food intake and activity of a group of urban adolescents
Authors: McNaughton Jean W. , Cahn Audrey J.
Published: May 2005

1. Information was obtained on the activity and food intake of ninety-two boys and 186 girls aged 16–19 years over a period of 7 days. Seventy-four boys and 132 girls were students, and eighteen boys and fifty-four girls were employed.

2. Each subject recorded daily activity on a chart divided into squares corresponding to 5 min, using a code letter for each type of activity. The amounts of all foods and beverages consumed each day were recorded in a food diary.

3. The energy expenditure of each subject was estimated from selected values for the energy cost of each activity. The intakes of calories and nutrients were calculated from tables of food composition.

4. It was found that the subjects spent very little time in strenuous physical exertion. There were slight differences between the age-group and the occupation groups, but between 78 and 80% of the total time was spent in bed or seated, 14–20% in very light to light physical activity and only 1.5–4.4% in any activity greater than walking at an even pace.

5. The group means for estimated energy expenditure in kcal, with their standard deviations, were: schoolboys aged 16–17, 2780 ± 250; employed boys aged 16–17, 2890±240; schoolboys aged 18–19, 2710±280; employed boys aged 18–19, 2749±270; schoolgirls aged 16–17, 2030±170; employed girls aged 16–17, 2140±240; schoolgirls aged 18–19, 2040±190; trainee teachers aged 18–19, 1900±140; employed girls aged 18–19, 2070±160.

6. Group means for the intake of kcal were: schoolboys aged 16–17, 3040±540; employed boys aged 16–17, 2730±520; schoolboys aged 18–19, 3110±450; employed boys aged 18–19, 2700–170; schoolgirls aged 16–17, 2140±420; employed girls aged 16–17, 1910±310; schoolgirls aged 18–19, 2400 ± 310; trainee teachers aged 18–19, 2020 ± 330; employed girls aged 18–19, 2030±440

7. The employed girls aged 16–17 had lower intakes of calories and all nutrients than the schoolgirls of the same age.

8. No correlation was found between the weight and calorie intake of individual subjects, nor between their calorie intake and energy expenditure during the time interval studied. The results indicated that for these Australian subjects, calorie balance was not achieved over a period of a few days. This is in accord with evidence of workers in other countries.

9. The findings suggest the need for further studies on the nutritional status of Australian employed girls aged 16–17.
A study of the energy expenditure and food intake of five boys and four girls
Authors: McNaughton Jean W. , Cahn Audrey J.
Published: May 2005

1. Assessments were made of the energy expenditure and food intake of five boys and four girls aged between 16 and 20 years.

2. The subjects recorded their activity over a 7-day period and weighed and recorded their food intake over the same period. The energy expended by them in performing specific activities, such as sitting, standing and walking, was measured by indirect calorimetry. The total daily energy expenditure of each subject was then counted. (Values were selected from the litera ture for the energy cost of the activities which we did not measure.)

3. The following range of values was obtained for the energy cost per min of various activities: sitting, 1.0–1.8 kcal, standing, 1.2–2.0 kcal; walking, 2.0–7.5 kcal; office work 1.1–1.9 kcal; laboratory work 1.4–2.3 kcal; playing table tennis, 4.6 kcal; riding a bicycle, 3.6–6.0 kcal; running, 5.2–7.5 kcal.

4. The means and standard deviations for daily energy expenditure and for calorie intake, respectively, expressed in kcal, of the individual subjects were: for the boys 2677±184 and 3348±668, 2285±91 and 2652±418, 2730±263 and 2985±625, 2638±338 and 2379±204, 2594±244 and 3150±692; for the girls 1939±234 and 2340±524, 2261±175 and 2064±376, 2131±148 and 2011±389, 2104±171 and 2454±469.

5. There was no correlation between the daily energy expenditure and calorie intake of any subject, nor was there any relation between the weight of individual subjects and either their total energy expenditure or calorie intake.

6. It is concluded that more precise methods of measuring the energy expenditure and calorie intake of individual subjects would need to be used in order to determine if there is any correlation between these two variables over short periods.

7. The results of this study tend to confirm the findings of other workers that calorie balance is only achieved over periods longer than 7 days.
Studies on plasma amino acids in East African adults in relation to endomyocardial fibrosis
Authors: Crawford M. A. , Gale M. M. , Somers K. , Hansen I. L.
Published: May 2005

1. An examination has been made of the plasma amino acids of adult Uganda Africans at risk to endomyocardial fibrosis compared with people from areas where the disorder is rare. The amino acid profile, both free and in the protein of the main staples, has also been examined.

2. Plasma tryptophan was found to be low in adults at risk and intermediate in Africans receiving a higher protein intake, as compared with Europeans whose protein intake might include more than 40 % as animal products.

3. Leucine and valine were also low in the plasma of adult Africans at risk.

4. The non-essential amino acids alanine and glycine were increased in the adult Africans at risk.

5. The similarity of these changes with the changes seen in kwashiorkor by other workers suggests that adherence to limited vegetable diets may introduce a chronic stress with regard to certain essential amino acids.

6. Studies on the vegetable staples used by Africans established that they are particularly poor in tryptophan and such Africans are probably dependent on other sources for their trypto-phan. None of the staples was a rich source of leucine. Plantain contained relatively large amounts of histidine, and cassava of arginine.

7. A comparative study of muscle protein suggests that the composition is similar regardless of diet and species. Leucine is quantitatively one of the most important amino acids in the muscle profile.

8.The above findings are discussed in the context of the requirements for heart muscle and the high incidence of cardiomyopathies within such African communities.
The effect of antibiotics on rats receiving a vitamin B12-deficient diet
Authors: Williams D. L. , Spray G. H.
Published: May 2005

1. Rats fed on a vitamin B12-deficient or -supplemented diet were given either neomycin or a mixture of streptomycin and erythromycin by mouth for between 7 and 15 d. The urinary excretion of methylmalonic acid and the levels of vitamin B12 in plasma and tissues and of acetic and propionic acids in caecal contents were measured.

2. Both treatments caused prompt reduction of methylmalonate excretion in the deficient rats. This was apparently due to depression of the production of some precursor of methyl-malonic acid, probably propionate, rather than to an immediate effect on vitamin B12 nutrition.

3. After withdrawal of the antibiotics, neomycin-treated vitamin B12-deficient rats appeared to become partly repleted in vitamin B12, but the change in the vitamin B12 status of those which had received streptomycin and erythromycin was much smaller.
The influence of frequency of sucrose intake on serum lipid, protein and carbohydrate levels
Authors: MacDonald I. , Coles Betty L. , Brice Judith , Jourdan M. H.
Published: May 2005

1. The changes in serum lipid and protein concentrations, and in carbohydrate tolerance were studied in eleven young male volunteers during a 3-week period of either nibbling or gorging a diet containing a high proportion of sucrose.

2. It was found that when gorging, the serum glyceride concentration rose early in the dietary period and reached a plateau, that the serum albumin concentration fell and that the glucose tolerance remained unchanged, although there was evidence for an increased rate of absorption of glucose.

3. On the nibbling regime, the serum glyceride concentration rose progressively over the 3-week period, the serum phospholipid concentration fell significantly and the serum albumin concentration fell but to a lesser degree than when gorging.

4. The glucose tolerance was improved when nibbling, and again there was evidence for an increased absorption of glucose.

5. An attempt is made to interrelate these findings.
The nutritive value of fat in the diet of the milk-fed lamb
Authors: Walker D. M. , Stokes G. B.
Published: May 2005

1. Thirty-five male cross-bred lambs at 3 d of age were given artificial milks with a protein- calorie concentration of 25 % and containing either lard, coconut fat, cottonseed oil, rapeseed oil, groundnut oil, soya-bean oil, safflower oil, tallow, maize oil or olive oil, homogenized with reconstituted skimmed cow's milk to provide 50 yo of the total energy of the diet. Two lambs were given a low-fat diet of reconstituted dried skim milk. All lambs were bottle-fed for 28 d.

2. The dietary fats and oils were highly digestible (97.2–99.5 %) with the exception of lard (89.1 %), rapeseed oil (61.9 %) and tallow (77.8 %). The indigestibility of these dietary fats was related to their content of stearic or erucic acids. The fatty acid patterns of the faecal fat were similar within each dietary group, but differed between diets.

3. Metabolic faecal fat excretion was 4.1 k0.5 g/100 g faecal dry matter. There was no similarity between the fatty acid composition of the metabolic faecal fat and that of the faecal lipids excreted by lambs given fat in their diet. The metabolic faecal fat made only a minor contribution to the total faecal lipids, so that the apparent and ‘ corrected’ digestibility coeffi-cients were very similar.
The nutrition of the veal calf
Authors: Roy J. H. B. , Stobo I. J. F. , Gaston Helen J.
Published: May 2005

1. Twenty-four bull calves consisting of fifteen Friesians and nine Ayrshires in a randomized block experiment were reared from birth on liquid diets offered ad lib. in two feeds daily to a slaughter weight equivalent to 22 % of mature cow weight of the breed.

2. The three diets given after the calves had received 7 kg whole colostrum were (a) fresh liquid skim milk containing 0.1 % butterfat, (b) a ‘high-fat’ diet containing reconstituted spray-dried skim milk and 2.8 % margarine fat, and (c) the ‘high-fat’ diet for 14 d from birth followed by liquid skim milk. All calves received supplements of magnesium and iron, and vitamins A, D and E. Digestibility and balance trials were made on nine calves of each breed at both 4 and 10 weeks of age. Certain observations were made at slaughter.

3. Dry-matter and gross energy intakes of calves given the skim-milk diet were greater than for those given the ‘ high-fat ’ diet. Daily weight gain, efficiency of food conversion, incidence of a high rectal temperature ( > 39.33°), mean rectal temperature and faecal dry-matter content were greater for the calves given the ‘ high-fat ’ diet. Age to slaughter and incidence of diarrhoea were much greater for the calves given liquid skim milk.

4. Apparent digestibility of lactose and apparent absorption of ash and calcium were greater withthe ‘high-fat ’diet, but no difference occurred in apparent digestibility of dry matter or protein. Metabolic faecal fat excretion was estimated from the intercept of the relationship between apparently digested fat and fat intake for the calves given the liquid skim-milk diets; the values obtained ranged from 29 mg/kg live weight for Friesian calves at 10 weeks to 49.5 mg/kg for Ayrshire calves at 4 weeks. The true digestibility of the fat was estimated.

5. No difference in Ca or nitrogen retention occurred between diets, but urinary N excretion and N retention/100 g gain in weight were markedly higher and concentration of N in the urine was much lower for calves given the skim milk.

6. Perirenal fat deposition per unit of metabolic body size was 168 % greater for calves given the ‘ high-fat ’ diet. Kidney weight and skin weight were greater for the calves given the liquid skim-milk diet. The increased kidney weight was related to the very large urine output of the calves given skim milk.

7. In comparison with Ayrshire calves, Friesian calves were much less susceptible to the adverse effects of liquid skim milk, having a lower incidence of diarrhoea and faeces of a higher dry-matter content, but they did have a higher incidence of lung lesions. Friesian calves also had a higher relative growth rate, efficiency of feed conversion, mean body temperature, faecal pH, apparent absorption of Ca, retention of N and Ca per unit of metabolic body size and killing-out percentage, but lower skin weight per unit of metabolic body size. Perirenal fat per unit of metabolic body size did not differ between breeds.
Incidence of protein deficiency in relation to different diets in India
Authors: Sukhatme P. V.
Published: May 2005

1. A method is presented for estimating the incidence of protein deficiency which takes due note of the association of protein deficiency with inadequate calorie intake and is applied to the data from dietary surveys in India. It is concluded that in only about one out of ten cases does protein deficiency occur as a direct result of inadequate protein intake. In the vast majority of cases protein deficiency is the result of inadequate intake of total energy. Protein which does not bring calories with it is therefore unlikely to make any significant contribution to the solution of the protein problem in India.

2. It is shown that diets based on cereals and pulses normally consumed by the people can meet man's needs for proteinat all ages provided enough food is taken to satisfy his energy needs. It is, however, important to ensure for infants a smooth transition from breast milk to solid diets. Special care is also necessary in the case of pregnant and lactating women.

3. The nature of protein deficiency is discussed in relation to different dietary patterns. The continuity implied in the bivariate distributions of calorie and protein intake is seen to provide a possible explanation of the experimental results on the development of kwashiorkor observed in animals on a diet short of both calories and protein and ondietspredominantly short of protein.
Intermittent and continuous faecal markers in short-term metabolic balance studies in young women
Authors: Sharpe Susan J. , Robinson Marion F.
Published: May 2005

1 The continuous faecal marker chromic oxide, Cr2O3, and the intermittent marker brilliant blue were used together in metabolic balance studies of calcium and magnesium in two young women.

2. Faecal output was derived by four methods: no marker, brilliant blue, Cr2O3, or both brilliant blue and Cr2O3.

3. Balances of Ca and Mg derived by the four methods of obtaining faecal output were compared.

4. Recovery of ingested Cr2O3 in the faeces appeared complete in experiments on three further subjects, with only a negligible amount being excreted in the urine.

5. Simultaneous use of both types of marker is recommended for short-term balance studies of nutrients such as Ca and Mg which are not readily absorbed.
Artificial rearing of pigs
Authors: Braude R. , Mitchell K. G. , Newport M. J. , Porter J. W. G.
Published: May 2005

1. Pigs were weaned from the sow at 2 d of age and reared on a diet of cow's milk supplemented with vitamin D, and antibiotics. The effects of four levels and two frequencies of feeding, and the temperature of the environment were studied in relation to the performance of the pigs and the digestion of the milk protein. Pigs fed at the two lower levels receivedadiet of cow's milk, but at the two higher levels cow's milk was spray-dried and reconstituted to 20% total solids. A comparison was also made between cow's milk and spray-dried reconstituted milk, both fed hourly with 12.5% total solids. The pigs were slaughtered at 28 d of age.

2. No differences in the nutritive value or digestion of the milk protein were found when cow's milk and reconstituted milk were fed with a total solids content of 12.5 yo.

3. Increasing the level of feeding resulted in a faster growth rate, and some deterioration in the feed conversion efficiency. The growth rate of the pigs from 2to 28 d of age when fed at a high level greatly exceeded that of sucking pigs reared on the sow. The retention of the dietary nitrogen also improved with increased feed intake. A highly significant inverse linear correlation of N retention with age was found at all levels of feeding. The milk protein was efficiently digested at all levels of feeding.

4. The mortality rate was very low but there appeared to be some association of losses with a high level of feeding during the first few days of life.

5. Feeding hourly compared with feeding twice daily improved the feed conversion efficiency, although the effect on growth rate and N retention was small. The retention of digesta in the stomach appeared to be an important factor in the regulation of the amount of digesta in the small intestine and in the maintenance of digestive efficiency. The stomachs of pigs fed twice daily contained considerably greater amounts of digesta than those of pigs fed at hourly intervals. There was little difference in the amount and composition of digesta in the small intestine and caecum at either frequency of feeding.

6. No differences were found in the performance of the pigs, N retention or the efficiency of digestion of the milk protein when the environmental temperature was maintained either at zoo throughout the experiment, or at 30' gradually reducing to zoo during the first 14d.
Calorie conversion factors. An experimental reassessment of the factors used in the calculation of the energy value of human diets
Authors: Southgate D. A. T. , Durnin J. V. G. A.
Published: May 2005

1. The intake and excretion of total nitrogen, fat and the various forms of carbohydrate, and the heats of combustion of the diet, urine and faeces were measured in groups of young men, young women, elderly men and elderly women.

2. Each group was studied while the subjects were eating two diets in turn, which differed in their contents of unavailable carbohydrate; the young women were also studied on a third diet which was rich in unavailable carbohydrate.

3. Increasing the intake of unavailable carbohydrate resulted in a greater faecal loss of energy, and in most instances of nitrogen and fat.

4. There was no significant effect of sex or age on the apparent digestibility of protein, fat or available carbohydrate.

5. The results are used to evaluate the use of calorie conversion factors for calculating the metabolizable energy content of mixed diets.

6. These show that for practical purposes the classical Atwater factors can be used to calculate the metabolizable energy of a diet with reasonable accuracy, provided that when available carbohydrate (as monosaccharides) values are used in the calculation a factor of 3.75 kcal/g (15.7 kJ/g) is used.

7. The studies demonstrate that the accuracy of any method for calculating the metabolizable energy of a diet is largely determined by the accuracy with which the method is capable of predicting the gross energy of the diet.
Effects of dietary glycerol on the serum glyceride level of men and women
Authors: MacDonald I.
Published: May 2005

1. The serum glycerides of men were raised 1–2.5 h after the ingestion of glycerol, whereas in young women given glycerol the serum glycerides were not raised. In men who had a supplementation of glycerol to their free-choice diet there was a rise in the concentration of fasting serum glycerides, a rise that was not found when a similar supplementation was given to young women.

2. These findings would support the tentative suggestion that dietary fructose does not follow the Emden-Meyerhof pathway to the same extent as glucose. The increased serum glyceride levels reported after high-fructose diets may be due to an increased availability of the glycerol moiety of glycerides.
Nucleic acid metabolism in the ruminant
Authors: Smith R. H. , Mcallan A. B.
Published: May 2005

1. Concentrations of nucleic acid nitrogen (NA-N) and other nitrogenous constituents were estimated in samples of rumen fluid taken from calves and cows which were either given stall diets of varying nitrogen content or were allowed to graze pasture. Concentrations of NA-N ranged from 1.5 to 27.5 mg/100 g water.

2. Ratios of RNA: DNA in rumen fluid were similar to those in rumen bacteria and were not related to those in the diets. Pure nucleic acids added to the rumen were rapidly degraded. It was therefore concluded that NA-N in rumen fluid was largely of microbial origin and provided an index of total microbial nitrogen.

3. In most experiments, with an individual animal consuming diets of various nitrogen contents, NA-N formed a fairly constant percentage (8-15 for different animals) of the total non-ammonia nitrogen in rumen fluid. This suggested that nitrogen entering the rumen fluid limited microbial growth. Consumption of a diet containing extracted decorticated groundnut meal (diet B), however, led to lower values for this percentage than did the other diets. Diet B was also exceptional in leading to marked diurnal variations in NA-N concentrations in rumen fluid, suggesting a cyclic fluctuation in the size of the microbial population.

4. Comparison of NA-N:total nitrogen ratios in rumen fluid and bacteria suggested that, for all the diets except diet B, 55–80 and 40–50% of the non-ammonia nitrogen in rumen fluid was of microbial origin for the calves and cows respectively.
Changes in the concentration of specific amino acids in the serum of experimentally malnourished pigs
Authors: Grimble R. F. , Whitehead R. G.
Published: May 2005

1. The concentrations of individual free serum amino acids have been studied during the course of chronic protein malnutrition in experimentally malnourished pigs.

2. Until growth was markedly impaired, reducing the protein content of the diet had no significant effect on serum amino acid composition.

3. During the period when growth had practically ceased but kcal intake per kg body-weight was normal the concentrations of valine, leucine, isoleucine, threonine and eventually tyrosine fell, the levels of alanine and serine were above control levels and aspartic acid, glycine, methionine, phenylalanine, proline, arginine, histidine and lysine remained unaltered.

4. When the kcal intake per kg fell below control levels, owing to anorexia, and the animals began to lose weight, the levels of alanine, glycine, serine and methionine fell and valine, leucine, isoleucine, threonine and tyrosine remained well below control levels.

5. The physiological, nutritional and metabolic significance of these findings is considered. The changes in alanine and glycine concentration are discussed in terms of the regulation of gluconeogenesis. The reduction of the branched-chain amino acids is interpreted on the basis of their availability for synthetic and catabolic needs.
The energy cost of human lactation
Authors: Thomson A. M. , Hytten F. E. , Billewicz W. Z.
Published: May 2005

1. The energy values of the diets of twenty-three women who were breast-feeding and thirty-two who were bottle-feeding their babies were determined by 7 d weighed surveys. All the subjects were healthy and living at home, and their babies were thriving. The lactating mothers took, on average, 591 kcal (2.5 MJ)/d more than those who were not lactating.

2. Both groups were losing weight, on average. The estimated contribution of such losses to the total energy supply was added to and the amounts expended on basal metabolism deducted from the dietary energy intakes. Since the activity of each group was fairly similar, it was possible to conclude that the average amount of energy available to support lactation was 618 kcal (2.6 MJ) daily. The average energy value of the milk produced was estimated from the weights of the babies to be 597 kcal (2.5 MJ) daily.

3. Critical evaluation of those averages, and of the assumptions on which they were based, led to the conclusion that the energy exchanges in human lactation have an efficiency of 90% or more, with a lower limit of about 80%.

4. The additional supply of 600 kcal (2.5 MJ) in the daily diet should suffice to support lactation and a ‘round figure’ of 500 kcal (2.1MJ) daily may be regarded as reasonable in official recommended allowances.
An investigation of the hyperaminoaciduria in phenylketonuria associated with the feeding of certain commercial low-phenylalanine preparations
Authors: Clayton Barbara E. , Heeley A. F. , Heeley Mary
Published: May 2005

1. Hypertryptophanaemia, hypertryptophanuria and to a lesser degree a generalized hyperaminoaciduria were observed in phenylketonuric patients receiving certain commercial low-phenylalanine diets containing DL-tryptophan.

2. The generalized hyperaminoaciduria was associated with the ingestion of acid hydro-lysates of protein, but not with the ingestion of enzymic hydrolysates or D-tryptophan.

3. Alanine recovered from the urine of these treated patients had a D-isomer content of approx. 50%. This amount of urinary D-alanine could be derived from the ingestion of an acid hydrolysate of protein in which the amino acids had racemized to the extent of 2–3%.
The absorption and distribution of the naturally occurring tocochromanols in the rat
Authors: Pearson C. K. , Barnes M. McC.
Published: May 2005

1. Groups of female albino rats were given 12–20 mg of one of the eight known toco-chromanols in 0.2 ml arachis oil by stomach tube, and were killed 2, 4, 8, 16 or 24 h afterwards. The liver, spleen, heart, kidneys, brain, small intestine and a portion of striated muscle were removed from each rat and analysed for the tocochromanol given.

3. Maximum levels of the tocochromanols occurred in most tissues 4–8 h after dosing. In the liver the tocopherols were more efficiently absorbed than were the corresponding toco-trienols. In kidney, heart and muscle the percentage uptake of the tocotrienols was often greater than that of the corresponding tocopherols.
Synthesis of microbial protein from ammonia in the sheep's rumen and the proportion of dietary nitrogen converted into microbial nitrogen
Authors: Pilgrim A. F. , Gray F. V. , Weller R. A. , Belling C. B.
Published: May 2005

1. The extent to which ammonia-N (NH3-N) serves as a starting point for synthesis of microbial nitrogenous compounds was assessed when 15N as (15NH4)2SO4 was continuously infused into the rumen of a sheep for periods of 78–98 h. Steady states were reached in the composition of the rumen contents because the animal was fed equal parts of its ration at hourly intervals. Concentrations of 15N in bacterial-N, protozoal-N and rumen NH3-N were compared.

2. In two trials with a low-N diet consisting largely of wheaten hay the 15N concentration in bacterial N was 76 and 78% of that in the NH3-N. For protozoa the values were more variable —64 and 43%.

In two trials with a higher-N diet (lucerne hay), the corresponding values were lower—bacterial-N 62 and 64%, protozoal-N 41 and 35%.It was concluded that synthesis of microbial protein was more dependent on ammonia as a starting point with the low-N diet than with the higher-N diet.

3. Entry and exit rates for ammonia into and out of the rumen system were determined, and the results, in combination with those obtained for bacterial-N in the first part of the work, allowed calculations to be made of the production of microbial-N/d formed from NH3-N, and this in turn allowed calculation of minimal values for conversion of plant-N to microbial-N in the lumen. Minimal extent of conversion was 68% for the low-N diet and 53–55% for the higher-N diet.

4. Total production of microbial-N in relation to the amount of N given was also calculated by using previously reported values for the relative proportions of protozoal-N and bacterial-N in sheep given diets similar to those used here. These values for extent of conversion were 73% for the low-N diet and 58–59% for the higher-N diet.
Copper deficiency in chicks: effects of ascorbic acid on iron, copper, cytochrome oxidase activity, and aortic mucopolysaccharides
Authors: Hunt C. E. , Landesman Joanne , Newberne P. M.
Published: May 2005

1. Copper deficiency was induced in newly hatched chicks by feeding on a milk-based diet for 12 d; effects of supplementation with ascorbic acid were studied.

2. Cu deficiency alone resulted in 30% mortality from aortic rupture. This was associated with a 20% increase in total acid mucopolysaccharides in the aorta, manifested as an increase in chondroitin sulphate and a relative decrease in hyaluronic acid. Cytochrome oxidase activity of liver and heart was less than half that of the controls.

3. Supplementing the Cu-deficient diet with 0.5 % L-ascorbic acid increased mortality to 40%, raised total aortic acid mucopolysaccharides to a higher level, and increased liver iron by 36%.

4. Supplementing the control diet with ascorbic acid decreased liver Cu by 30% and significantly reduced total aortic acid mucopolysaccharides.

5. The enhancement of the Cu-deficiency effect by ascorbic acid probably results from interactions between ascorbic acid and absorption or metabolism of Cu; untoward effects of supplementing the control diet with ascorbic acid may be interpreted as manifestations of ascorbic acid toxicityper se.