bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of linseed oil and of linseed oil fatty acids incorporated in the diet on the metabolism of sheep
Authors: Czerkawski J. W. , Blaxter K. L. , Wainman F. W.
Published: June 2005

1. Three sheep were given three diets, a control diet consisting mainly of cereals, a similar diet incorporating linseed oil (mainly glycerides of linolenic acid) and a diet incorporating free fatty acids derived from linseed oil. The diets were given at the maintenance level and at twice this level according to a latin square design. 2. Complete energy balance was obtained and the digestibilities of cellulose and lipid were determined with each sheep receiving each diet. The relative amounts of various fatty acids in the dietary and faecal lipids were also estimated. 3. The inclusion of lipids in the diet resulted in a significant decrease in cellulose digestion, whereas the lipid digestibility increased. 4. The proportion of C18acids increased in the faeces, and the proportion of bacterial fatty acids decreased, but since the total amount of fatty acids excreted increased, the amount of bacterial fatty acids excreted per day did not differ significantly in animals receiving the control diet and the diets containing added lipids. 5. The addition of lipids to the diet resulted in a highly significant drop in methane production, the depression being about 25% of the control value. The depression (28.9 kcal/100 kcal of fatty acids given) was considerably greater than the depression produced by continuous infusion of the same amount of fatty acids. 6. Because of the depression of CH4production and of some reduction in the urinary energy losses, the addition of lipids to the basal diet increased the metabolizable energy by about 9.5 kcal/100 g of the basal diet. 7. The efficiencies of utilization of metabolizable energy were not significantly affected by addition of lipids, being about 82% for maintenance and 62% for fattening. 8. In an experiment with one sheep, comparison was made between the effect of slow continous infusion of fatty acids over 24 h and the effect of rapid infusion of the same amount twice daily during feeding. The continuous infusion of linseed oil fatty acids resulted in a drop in CH4production of 16.3 kcal/100 kcal of fatty acids given. This was in good agreement with previous findings. Rapid infusion of these fatty acids resulted in a drop in CH, production, amounting to 28.0 kcal/100 kcal of fatty acids infused. This is comparable with the reduction of 28.9 kcal/100 kcal fatty acids when the fatty acids were incorporated in the diet.
Utilization of salts of volatile fatty acids by growing sheep
Authors: Ørskov E. R. , Allen D. M.
Published: June 2005

1. Two experiments are reported in which sodium and calcium salts of volatile fatty acids (VFA) were given to lambs as additions to two basal dietsof hay andconcentrate. The two diets induced distinctly different types of rumen fermentation. A low-concentrate diet gave higher acetic and lower butyric acid proportions in the rumen contents than a high-concentrate diet. The two diets were given to lambs to provide equal intake of digestible organic matter. In one change-over experiment with twelve sheep the nitrogen retention was determined, and in a second experiment involving sixty-four lambs the efficiency of the VFA salt to promote body-weight gain was estimated. 2. The estimated metabolizable energy (ME) from the high-concentrate diet was utilized significantly more efficiently than that from the low-concentrate diet to promote positive nitrogen retention and to increase empty body-weight and carcass weight. These differences in final live weight were not significant owing to the greater content of the alimentary tract of lambs given the low-concentrate diet. 3. On both diets the lambs receiving the additions of VFA salts grew faster and produced significantly greater empty body and carcass weights than the lambs receiving only the basal diets. 4. For promoting carcass gain the energy derived from the VFA salts appeared to be utilized more efficiently than the calculated ME above maintenance of the two basal diets. 5. There were no significant differences between the efficiency of utilization of the energy from acetate, propionate and butyrate to promote carcass gains. There was, however, a tendency for the response to acetate to be greater on the high-concentrate diet than on the low-concentrate diet. 6. With a low level of feeding but with positive N balance, addition of acetate resulted in a greater N retention than that of propionate with both diets. 7. It is concluded that if the reported low utilization of the ME of diets high in roughage is related to the proportion of acetic acid in the rumen contents, then the implied losses of energy may be associated with the formation of acetic acid rather than its utilization.
The effect of an atherogenic diet on plasma lipid composition and aortic atherosis in two strains of New Zealand White rabbit
Authors: Moore J. H. , Williams D. L.
Published: June 2005

1. Susceptibility to dietary induction of hypercholesterolaemia and aortic atherosis was compared in two groups of male New Zealand White rabbits. 2. Twelve rabbits were purchased from one breeding establishment (group I) and twelve from another (group 2). On arrival at the laboratory six animals from each group were killed and the aortas were removed. Blood samples were taken from the remaining twelve animals and then they were givenad lib.for a period of 40 weeks an atherogenic diet containing 20% butterfat. During this period food intake and body-weight were recorded. At the end of the period blood samples were taken from the animals and immediately afterwards they were killed and the aortas were removed. 3. No atheromatous lesions were found in the aortas of the rabbits in either group killed at the beginning of the experiment. There were no differences between the two groups of animals with respect to body-weight or concentration of cholesterol in the plasma at the beginning of the experiment, food intake during the experiment or body-weight at the end of the experiment. At the end of the experiment, the degree of aortic atherosis in the rabbits of group I was considerably greater than that in the rabbits of group 2. 4. At the end of the experiment the concentrations of total lipids, free cholesterol, esterified cholesterol and phospholipids in the plasma of the rabbits in group 1 were significantly higher than the corresponding concentrations of these lipid components in the plasma of the rabbits in group 2. The concentrations of palmitic, stearic and linoleic acids in the cholesterol esters and the concentration of palmitic acid in the unesterified fatty acids in the plasma of the rabbits in group 2 were significantly higher than the corresponding concentrations of these fatty acids in the plasma cholesterol esters and unesterified fatty acids in the rabbits of group 1. 5. It is concluded that these differences in response to the atherogenic diet were reflections of the differences in the susceptibilities to the dietary induction of hypercholesterolaemia and atherosis of the two differents strain of rabbit that had been established by the two commercial breeders. Such differences in susceptibility could readily explain certain discrepancies in the results of various research workers engaged in this field of investigation.
Protein malnutrition in the rat induced by protein-calorie imbalance
Authors: Wikramanayake T. W.
Published: June 2005

1. A study has been made of the effect of feeding growing rats for a long time on a low-protein, high-carbohydrate diet given at two different levels of energy. 2. When the proteins of the diet provided o or 5% of the calories the body-weight fell rapidly and fat accumulated in the liver. Addition of carbohydrate (glucose) to the diets increased the amount of fat in the liver. 3. It is suggested that a deficiency of protein retards the synthesis in the liver of lipoproteins required for removal of triglyceride from the liver. Additional carbohydrate diverts amino acids from the amino acid pool to tissues such as muscles, increasing the liver damage.
Protein requirements in tropical countries: nitrogen losses in sweat and their relation to nitrogen balance
Authors: Ashworth Ann , Harrower A. D. B.
Published: June 2005

1. An experiment was undertaken to determine whether high rates of sweating in a tropical climate affect protein requirements by increasing the total nitrogen losses from the body.

2. Six fully acclimatized volunteers were given a diet supplying 50 g protein (= 8 g N) daily. They performed strenuous physical work of a normal nature for an average of 6½ h a day for two 5-day periods. During control periods the subjects took minimal exercise and lived in a cool environment. N balance was measured throughout.

3. Rates of sweating were measured by weighing. Whole body sweat was collected and the concentrations were measured of nitrogen, sodium and potassium. During 6½ h work approximately 3 l. of sweat were lost, containing on average 0·49 g N, 64 m-equiv. Na and 22 m-equiv. K.

4. The N concentration in sweat was 0·20 mg/g, which is lower than that found by most other workers. It is suggested that acclimatization is an important factor in reducing N loss by sweating.

5. There was a marked decrease in urinary Na excretion during sweating, which compensated fully for the loss of Na in sweat. Renal compensation for loss of K was less efficient.

6. Because the total N loss in sweat was small, it was not possible to establish with certainty whether it was compensated for by a reduced renal excretion of N. However, after the initial period the subjects were in N balance in spite of the relatively low protein intake.

7. It is concluded that there is no evidence to suggest that heavy sweating under natural conditions in a tropical climate causes a significant increase in protein requirements.
Effect of groundnut meal containing aflatoxin on Cynomolgus monkeys
Authors: Cuthbertson W. F. J. , Laursen A. C. , Pratt D. A. H.
Published: June 2005

1. Both male and female Cynomolgus (Macaca irus) monkeys survived for 3 years without apparent ill health when fed on diets containing groundnut meal to provide up to 0·36 μg aflatoxin B1per g diet and thus supplying a mean daily consumption of up to 2 μg aflatoxin B1per kg body-weight. No histological changes attributable to aflatoxicosis were discovered in any of the organs from the monkeys receiving these quantities of aflatoxin.

2. Few monkeys survived for more than a month or two when given a diet containing 1·8 μg aflatoxin B1per g, which provided about 50 μg aflatoxin B1per kg body-weight per day.

3. No depression in growth rate nor effect on health was noted in those monkeys which survived on diets containing 1·8 μg aflatoxin B1, nor in any of the other monkeys.

4. Histological changes were observed in the livers of all monkeys receiving the diet containing 1·8 μg aflatoxin B1per g for more than a month or two, but no abnormalities related to aflatoxicosis could be detected in any of the other organs, except for minor changes in the kidneys of two monkeys.

5. No tumours were seen in any of the monkeys, even in those surviving for 3 years on diets providing 1·8 μg aflatoxin B1/g. Thus, no conclusions can be drawn from this work as to the carcinogenicity of aflatoxin in monkeys (still less in man), because the animals were young and little is known of the duration of exposure required to demonstrate carcinogenicity in this species.
The nutritional value of poor proteins fed at high levels
Authors: Carpenter K. J. , Anantharaman K.
Published: June 2005

1. Groundnut flour plus lysine, fed to young rats at a high level as their sole source of protein supported weight gain and nitrogen retention equal to that on what has been considered the ‘ideal’ egg protein diet. For every 100 metabolizable kcal of the groundnut diet that were consumed, 41 came from the dietary protein and there was a net retention of protein equivalent to 14·5 kcal.

2. The predicted retention of protein according to the equations of Miller & Payne (1961) for this methionine-deficient protein source, given a score of 56 by FAO (1957), would have been equivalent to only 6·1 kcal and, whatever the level of such a protein in a diet, the maximum predicted retention would be equivalent to no more than 8·5 kcal, or 60% of the best expected with egg as the protein source.

3. Feeding a lysine-deficient protein source, wheat gluten, at high levels also gave a greater N retention than had previously been predicted.

4. It is concluded that the Miller & Payne (1961, 1963) equations can greatly under-estimate the performance to be obtained from feeding poor proteins at high levels. A revised equation (P. R. Pane, Private communication) predicts much higher results under these conditions.
Digestion of concentrate and of hay diets in the stomach and intestines of ruminants
Authors: Topps J. H. , Kay R. N. B. , Goodall E. D.
Published: June 2005

1. The flow of digesta to the abomasum and through the duodenum and terminal ileum was measured over 24 h periods in sheep. Pelleted diets of concentrates, principally composed of barley, and of poor-quality hay were given. The seven Scottish Blackface ewes studied were all fitted with rumen cannulas, and in addition two had simple abomasal cannulas, one a re-entrant abomasal cannula, two re-entrant duodenal cannulas, and two re-entrant ileal cannulas.

2. Paper impregnated with chromium sesquioxide was given twice daily by rumen fistula. The amounts of dry matter, starch, cellulose, total nitrogen and energy passing through the abomasum, duodenum and ileum and the amounts excreted in the faeces were measured. The flows of digesta were adjusted to give 100% recovery of chromium sesquioxide and the extent of digestion in various parts of the alimentary tract was calculated using these adjusted values. Concentrations of glucose in the blood and of volatile fatty acids (VFA) in the rumen were also measured.

3. For the concentrate diet, 69% of the digestible dry matter disappeared in the stomach (reticulo-rumen, omasum and abomasum), 17% in the smail intestine and 14% in the large intestine. Values for disappearance of digestible energy were 72% in the stomach, 23% in the small intestine and 5% in the large intestine. Of the 298 g starch fed daily only 6–35 g passed through the abomasum or duodenum and only 1–4 g reached the terminal ileum. The cellulose in the diet was poorly digested.

4. For the hay diet, 67% of the digestible dry matter disappeared in the stomach, 22% in the small intestine and 11% in the large intestine. Values for disappearance of digestible energy were 81% in the stomach, 7% in the small intestine and 12% in the large intestine. Of the 33 g of starch consumed daily, from 5 to 13 g passed through the abomasum or duodenum. The cellulose in the hay was 59% digestible and virtually all this digestion took place in the stomach.

5. The concentration of VFA and the proportion of propionate in the rumen fluid, 2·5 h after feeding, were considerably greater on the concentrate diet than on the hay diet, but diet had little influence on the concentration of blood glucose.

6. The importance of the small amount of starch passing to the sheep's small intestine is discussed.
The continuous recording of the pH in the bovine rumen
Authors: Johnson V. W. , Sutton J. D.
Published: June 2005

1. Details are given of modifications to standard pH measuring equipment enabling it to be used to record continuously the pH in the bovine rumen for up to 4 weeks. The operation of the apparatus and examples of its use are presented.
The fate of water in the rumen
Authors: Warner A. C. I. , Stacy B. D.
Published: June 2005

1. A mathematical treatment is given of the marker technique for studying water balances in the rumen. The treatment is extended to cover non-steady-state conditions and emphasis is placed on the underlying assumptions and practical limitations of the technique.

2. The 51Cr complex of ethylenediamine tetra-acetic acid (51Cr EDTA) was used as a marker in the rumen of sheep.

3. The 51Cr EDTA entered 95–98% of the water in the rumen. Mixing in the rumen, though adequate, was usually not quite complete even 1·5 h after injection of the dose. The techniques of injecting the dose and of withdrawing the sample were found to be important; some techniques often led to poor mixing.

4. Provided that the time of injection of the dose was suitably selected, reliable estimates of the volume of water in the rumen could readily be made, but reliable estimates of flow rates needed stringent attention to details of technique.
Further studies on the problem of goitre in Ceylon
Authors: Mahadeva K. , Seneviratne D. A. , Jayatilleke D. B. , Shanmuganathan S. Senthe , Premachandra P. , Nagarajah M.
Published: June 2005

1. A comparative study of the iodine and calcium contents of diets in areas of Ceylon where goitre is endemic and non-endemic was carried out.

2. The iodine content of food grown in non-endemic areas was, in most instances, considerably higher than in endemic areas.

3. In endemic areas the daily average intake per person per day was well above the allowance of 100–150 μg recommended by most workers. The critical level of total daily iodine intake below which goitre becomes endemic in Ceylon was 400 μg. Possible reasons for this higher need of iodine are discussed.

4. Addition of iodine to cooking salt has been used successfully to combat endemic goitre in many countries. The amount of iodine added is based on the degree of endemicity and the amount of salt consumed per person per day. It is suggested that the more important criteria which should determine the amount of iodine added to cooking salt are the dietary iodine content, the daily total intake of dietary iodine and particularly the level of iodine below which goitre becomes prevalent.
The effects of feeding toxic groundnut meal to growing pigs and its interaction with high-copper diets
Authors: Barber R. S. , Braude R. , Mitchell K. G. , Harding J. D. J. , Lewis G. , Loosmore R. M.
Published: June 2005

1. Three experiments using sixty individually fed, enzootic pneumonia-free Large White pigs on experiment from 9–11 weeks of age to 200 lb live weight are described.

2. Information was obtained on the effect of different dietary concentrations of aflatoxin B1 on the performance of the pigs, on various biochemical measurements and on the histology of the livers and kidneys.

3. Reduced growth rate and loss of appetite were the main adverse effects observed, their extent being positively related to the dietary level of aflatoxin B1. No marked clinical signs were seen, mortality was very low and there was little or no effect on the feed conversion efficiency of the animals.

4. No evidence for any adverse interaction between aflatoxin B1 and the presence in the diet of a supplement of copper sulphate providing 250 ppm Cu was apparent from either the performance, biochemical or histological results obtained. It was concluded that the few isolated reports of toxicity in growing pigs fed diets containing a supplement of 250 ppm Cu were unlikely to have been the result of the unsuspected presence of aflatoxin B1 in the feedingstuffs used in the diets.

5. Aflatoxin B1 tended to increase the serum alkaline phosphatase level, the concentration of Cu in the kidneys, and liver weight and to reduce the liver vitamin A concentration. No other consistent differences in the measurements made were observed.

6. The extent of the total pathological abnormality observed in the livers and kidneys was closely related to the level of aflatoxin B1 in the diet.
Metabolic responses to low doses of cyanocobalamin in patients with megaloblastic anaemia
Authors: Adams J. F. , Hume R. , Kennedy Elizabeth H. , Pirrie T. G. , Whitelaw J. W. , White A. M.
Published: June 2005

1. The metabolic responses to daily treatment with 1 μg cyanocobalamin were studied in sixteen patients with megaloblastic anaemia due to cobalamin deficiency.

2. The fall in serum iron was sluggish in most patients. The pattern of reticulocyte responses varied widely, the most common being a plateau with suboptimal maximal value.

3. Urinary propionic acid excretion before treatment was normal in two out of six patients. A transient rise during treatment was observed in two patients, possibly owing to demands on coenzyme stores. The fall in urinary propionic acid excretion during treatment was slow.

4. Serum vitamin B12levels rose during treatment. In two patients an abrupt rise was found, possibly owing to release of stored cobalamin into the circulation.
The effect of high salt intake or restricted water intake on diet selection by sheep
Authors: Wilson A. D.
Published: June 2005

1. In three experiments sheep were offered a choice of two rations: one high in NaCl (7.5 or 15%) and one low in NaCl. The intake of each ration was recorded when fresh water was freely available, when increasing amounts of NaCl were added to the drinking water and when the amount of fresh water available was restricted.

2. Low levels of NaCl in the drinking water or mild restriction of available water were without effect on the diet selected. At higher levels, total food intake was reduced and the reduction was sustained entirely by the high-salt ration. The intake of the low-salt ration remained the same or increased, so that the selected diet then contained an increased proportion of the low-salt ration. The effects of adding NaCl to the drinking water and of water restriction were similar.

3. It was concluded that sheep with a choice of high- and low-salt rations can partly avoid the stress of saline drinking-water or restricted water supply by changing the proportion of each ration eaten.
Factors affecting the polyunsaturated fatty acid content of the plasma lipids of sheep
Authors: Moore J. H. , Noble R. C. , Steele W.
Published: June 2005

1. In Expt 1, four adult wether sheep were given diets of hay or dried grass in an alternating sequence of feeding treatments. Each treatment period lasted for 20 days and blood samples were taken from the sheep on the last day of each period. When the diet of hay (linoleic: linolenic acid ratio 1.40) was replaced by one of dried grass (linoleic: linolenic acid ratio 0.28), there was an increase in the concentration of linolenic acid and a decrease in the concentration of linoleic acid in the plasma cholesteryl esters and phospholipids. There was an increase in the concentration of stearic acid and a decrease in the concentration of palmitic acid in the plasma triglycerides. Dietary change did not affect the composition of the plasma unesterified fatty acids.

2. In Expt 2, two adult wether sheep, each with a rumen fistula, were given daily intraruminal infusions of 60 g of ‘linolenic’ or ‘linoleic’ acids (both about 70% pure) over a period of 5 days. The infusion treatments were then reversed. Blood samples were taken at the end of each infusion period. Intraruminal infusions of ‘linolenic’ acid increased the concentration of linolenic acid in the plasma cholesteryl esters and phospholipids and increased the concentration of stearic acid in the plasma triglycerides. The infusions of ‘linoleic’ acid increased the concentration of linoleic acid in the plasma cholesteryl esters and phospholipids. No appreciable changes were observed in the composition of the plasma unesterified fatty acids.
Efficiency of digestion in germ-free and conventional rabbits
Authors: Yoshida T. , Pleasants J. R. , Reddy B. S. , Wostmann B. S.
Published: June 2005

1. Germ-free (GF) and conventional (CV) rabbits wearing collars to prevent coprophagy were fed an autoclaved diet with added cellulose. Their faecal excretion was analysed to determine nutrient digestibility.

2. Clearly distinguishable hard faeces were excreted by the GF rabbit only if the diet contained at least 15% cellulose. Unlike CV rabbits, the GF rabbits did not consume their soft faeces even when permitted to do so. Soft faeces made up a larger proportion of the total output of GF than of CV rabbits. Food intake and total dry-matter excretion per kg body-weight were similar in both groups.

3. Although digestibility of dry matter was similar in the two groups, in the GF rabbits there was a higher digestibility of crude fat and true protein and a lower digestibility of crude fibre and nitrogen-free extract. GF rabbits excreted a higher percentage of ingested calcium and phosphorus in the urine than did CV rabbits.

4. The results suggest that intestinal microbes, even without the enhancing effect of coprophagy, aid in the digestion of carbohydrate by rabbits. The greater faecal excretion of crude fat and true protein by CV rabbits could result from poorer digestion and absorption, but could also represent nutrients synthesized by microbes from simpler materials. The reingestion of faecal crude fat and true protein might therefore improve the quality of the total nutrient intake. The results suggest ways of assuring an adequate dietary intake by GF rabbits in the absence of contributions from an intestinal microflora.
Pathogenesis of oedema in protein-energy malnutrition: the significance of plasma colloid osmotic pressure
Authors: Fiorotto Marta , Coward W. A.
Published: June 2005

1. Rats were made oedematous by feeding them low-protein diets (protein: energy (P:E) 0.005) ad lib., and measurements were made of plasma and interstitial fluid colloid osmotic pressures (πp and πi respectively) and interstitial fluid hydrostatic pressure (Pi) before, and at the onset of, oedema formation. Taken together as (πp − πi + Pi) these forces oppose capillary pressure (Pc) and thus determine rates of transcapillary water filtration. Interstitial fluid was sampled, in non-oedematous and oedematous animals, from perforated capsules implanted subcutaneously for the measurement of Pi. Blood, plasma and interstitial fluid volumes were also determined.

2. In Expt I comparisons were made between animals fed on a control
diet (P:E 0.210) and the lowprotein diet. In normal animals the ratio πp:πi was approximately 2, but in protein deficiency it was increased since reductions in the absolute value of πi matched those in πp. These changes were observed 2 weeks after the start of the experiment and became more exaggerated when oedema appeared (weeks 18–22).

3. Pi was normally negative with respect to atmospheric pressure but increased to values close to zero when oedema formation occurred.

4. Despite the reductions in πp that were seen in the protein-deficient animals the sum of the forces opposing filtration (πp − πi + Pi) did not change significantly during the experiment.

5. Plasma and interstitial fluid volumes expressed per kg body-weight (measured using 125I-albumin and 35SO42−) were unchanged as πp initially decreased in the protein-deficient animals but increased markedly with the onset of oedema.

6. In Expt 2 comparisons were made between animals fed the low-protein diet ad lib. and others fed on the control diet in restricted amounts so that weight loss was the same in the two groups of animals.

7. The wasting induced by restriction of the control diet did not produce reductions in πp or πi and values for Pi were normal. Changes in the animals fed on the low-protein diet were similar to those observed in Expt I. By using 51Cr-labelled erythrocytes it was shown that the expansion in plasma volume that occurred when oedema appeared in the protein-deficient animals was mainly due to a reduction in total erythrocyte volume. Blood volume did not increase significantly.

8. It was concluded that in the hypoproteinaemia induced in the experimental animals reductions in the value of πp, which might otherwise result in an imbalance of forces that would produce excessive rates of transcapillary water filtration, were compensated for by reductions in πi. Increases in Pi also compensated but were quantitatively less important.

9. The significance of the results is discussed in terms of the pathogenesis of oedema in kwashiorkor and the concept of an oncotic threshold for oedema formation in hypoproteinaemia.
Fermentation and nitrogen dynamics in Merino sheep given a low-quality-roughage diet
Authors: Nolan J. V. , Stachiw S.
Published: June 2005

1. Fermentation in the rumen and nitrogen dynamics in the body were studied in mature Merino sheep given a maintenance ration of a low-quality-roughage diet containing mainly chopped wheat straw.

2. Intake of metabolizable energy was 3.49 MJ/d and of total N 6.2 g/d.

3. From measurements of volatile fatty acid (VFA) production rates and stoichiometric principles, it was calculated that 75% of the digestible organic matter intake was fermented in the rumen, making an estimated 44 g/68d microbial dry matter available to the animal.

4. The total flux of ammonia through the rumen NH3 pool, estimated by 15NH3 dilution methods, was 8.2 g N/d of which 3.5 g N/d was irreversibly lost; thus 4.7 g N/d was recycled, partly within the rumen (approximately 3.8 g N/d) and partly via endogenous secretions (approximately 0.9 g N/d). The extensive recycling of NH3-N within the rumen indicated that turnover of microbial N was considerable, and the total production of micro-organisms was at least twice the net outflow.

5. The proportion of the N in rumen bacteria derived from rumen ammonia was 62% and thus 38% was derived from other nitrogenous compounds such as peptides and amino acids.

6. The rates of transfer of blood urea into the rumen, estimated from the appearance of 14CO2 or 15NH3 in the rumen after intravenous single injections of [14C]-and [15N]urea, did not differ significantly and the mean transfer was 2.3 urea-N/d.

7. Estimates of the rate of irreversible loss of urea-C (i.e. urea synthesis in the body) were obtained by analysis of samples of either blood or urine obtained after a single, intravenous injection of [14C]urea. The two methods gave results that did not differ significantly. The estimated rate of urea synthesis in the body was 5.3 g N/d. Urea excretion rate was relatively low, i.e. 1.2 g N/d, and thus transfer of urea to the digestive tract was approximately 4.1 g N/d. Approximately 53% of the latter was transferred to the rumen, and 47% to the rest of the digestive tract. These results are discussed in relation to similar studies with sheep given other diets.

8. Various aspects of isotope-tracer methods and the errors that could occur in this type of study are discussed.
The effects of defaunation of the rumen on the growth of lambs on low-protein-high-energy diets
Authors: Bird S. H. , Hill M. K. , Leng R. A.
Published: June 2005

1. The effects of defaunation of the rumen of lambs given low-protein-high-energy diets were studied using animals fedad lib.a basal diet of sugar and oaten chaff which was supplemented with fish meal at various levels. These diets supported relatively large populations of protozoa in the rumen.

2. A nonly phenol ethoxylate (15 g, Teric GN9; ICI Australia Ltd) given intraruminally, was shown to be an effective means of defaunating the rumen and the lambs were maintained protozoa-free by isolation.

3. In lambs given low levels of fish meal in the diet, the absence of rumen protozoa increased growth rate and improved the food conversion efficiency (g dry matter intake/g growth). These effects were not apparent at high levels of protein supplementation.

4. These results suggested that the absence of rumen protozoa resulted in an increased availability of nutrients supplying both energy and amino acids since the efficiency of food utilization and the rate of wool growth (which is sensitive to amino acid supply) were increased in lambs on the low level of protein supplementation without apparently increasing food intake.
Experiments with the long-term rumen simulation technique (Rusitec); use of soluble food and an inert solid matrix
Authors: Czerkawski J. W. , Breckenridge Grace
Published: June 2005

1. The role of soluble nutrients and of the solid matrix in rumen fermentation was investigated in some detail, and experiments designed to explore the possibility of using a balanced soluble diet and an inert solid matrix, are described.

2. The use of a balanced soluble substrate as the only source of nutrients in the presence of an inert solid phase in the reaction vessels results in vigorous fermentation but is accompanied by disappearance of protozoa from the effluent.

3. In the absence of digestible solid phase, the rate of fermentation and the fermentation pattern depends mainly on the amount and type of nutrients supplied and to a smaller extent on the dilution rate, the variations being greatest at low dilution rates.

4. The solid matrix in the form of wood shavings or the residue remaining after prolonged digestion of hay could sequestrate micro-organisms and could be used as solid phase, but the defined mixture of soluble substrates used resulted in somewhat abnormal fermentation compared with fermentation obtained with solid food.

5. When the solid food included some hay extract and when the dilution rate was not too great a reduced output of protozoa could be maintained. At high dilution rate the outflow of protozoa was negligible and yet considerable numbers of protozoa were found in the solid matrix and associated liquid.

6. A three-compartment model was developed to describe the flow of liquid and microbial matter within the simplified system.
Availability of iron from chicken meat and liver given to rats
Authors: Bogunjoko Funke E. , Neale R. J. , Ledward D. A.
Published: June 2005

1. The concentration and distribution of iron in 59Fe-labelled chicken leg and breast meat and liver were determined by gel filtration. In all samples approximately 50% of the Fe was insoluble (haemosiderin) and the haemoproteins (haemoglobin and myoglobin) constituted from 15% (liver) to 25% (leg meat) of the total Fe. Ferritin accounted for from 12% (leg meat) to 27% (liver) of the total Fe.

2. A technique was developed which enabled the time-course of the passage of 59Fe-labelled whole and fractionated meat and liver through the gastrointestinal tract of Fe-replete and Fe-deficient rats to be followed and it was found that the rate of stomach emptying appeared to be a function of the viscosity of the meal. In Fe-replete rats approximately 71% of a meal of raw chicken meat had left the stomach within 1 h of administration and by 2 h the stomach was almost empty and much of the unabsorbed 59Fe was in the ileum. By 4 h the ileum and colon contained almost equal amounts of 59Fe. Between different test meals there were only slight differences in gastrointestinal distribution and these reflected the different rates of stomach emptying.

3. Stomach emptying was slower in Fe-deficient compared with Fe-replete rats.

4. In Fe-replete, but not Fe-deficient, rats it was found that the amount of 59Fe lost (absorbed) from the gastrointestinal tract 2 h after administration of a test meal was not significantly different from the value found using a 7 d faecal collection technique.

5. Comparison of the 2 h absorption values for several test meals indicated that 59Fe absorption from raw whole meat was significantly higher than from the soluble extract and the residue after extraction (haemosiderin).

6. Heat treatment caused a significant decrease in the absorption of Fe in whole meat and the soluble meat extract but a significant increase in the liver absorption values. It is suggested that denatured haemoproteins are less available for absorption than their native forms but that heating increases the availability of the Fe of haemosiderin or ferritin or both.

7. Isolated muscle ferritin was poorly absorbed but on the addition of excess bovine serum albumin the absorption of the Fe was markedly increased.

8. It is concluded that, to estimate the Fe availability of a food such as chicken meat or liver one must not only take account of the concentration and type of each Fe-containing compound present but also such factors as their possible synergistic effects, the presence of chelating agents, the extent of cooking and the concentration and type of proteinaceous digestion products.
Similar serum lipoprotein reductions by lipid-lowering diets with different polyunsaturated:saturated fat values
Authors: Gustafsson Inga-Britt , Boberg J. , Karlström B. , Lithell H. , Vessby B.
Published: June 2005

1. Lipid-lowering diets enriched in polyunsaturated fat decrease the serum cholesterol in hyperlipoproteinaemia, usually by reducing both the low-density-lipoprotein (LDL) and high-density-lipoprotein (HDL) cholesterol concentrations. The aim of the present study was to investigate whether the effects on LDL could be maintained but those on HDL cholesterol be diminished by reducing the ratio, polyunsaturated: saturated fat (P:S) of the diet.

2. Twenty hyperlipoproteinaemic patients (six with type IIa, eight with type IIb and six with type IV) in a metabolic ward were given two fat-modified diets during two consecutive 3–week periods in a randomized order. The diets were identical with regard to nutrient composition but differed with regard to the P:S values, which were 2.0 and 1.3 respectively.

3. The lipoprotein-lipid composition and serum apolipoprotein concentrations were similar at the end of the two dietary periods in type IIa and type IV patients but in type IIb patients a more pronounced reduction of the LDL-cholesterol concentration by 9% (P< 0·05) was achieved on the diet with the higher P:S value. The HDL-cholesterol did not differ significantly.

4. The results indicate that increasing the P:S value of lipid-lowering diets from 1.3 to 2·0 does not offer a great advantage with regard to the lipoprotein-lipid reductions achieved in moderate hyperlipoproteinaemia.
Measurement of water-holding properties of fibre and their faecal bulking ability in man
Authors: Eastwood M. A. , Robertson J. A. , Brydon W. G. , MacDonald Dorothy
Published: June 2005

1. Experiments to measure the effect of a fibre source in the diet on stool bulk are difficult and lack precision. In vitro methods which would identify fibre sources that are effective for clinical and epidemiologic use would be valuable. One important property of fibre which influences the ability of fibre to increase stool weight is its water-holding capacity (WHC).

2. WHC was measured using centrifugation, filtration, suction pressure and water flow-rate techniques using fibre concentrates of potato, cereal bran and gum arabic.

3. Dietary supplementation of three preparations of potato fibre (20 g/d) had no significant effect on stool weight but 16 g bran/d increased stool weight from 107 (SE 44) g/d to 174 (SE 51) g/d.

4. The effects of these fibres on stool weight can be related to the nature of the water-holding properties of fibre rather than absolute WHC.
Rumen protein degradation and biosynthesis
Authors: Raab L. , Cafantaris B. , Jilg T. , Menke K. H.
Published: June 2005

1. A method is described for the determination of protein degradation based on measurements of ammonia concentration and gas production (Menke et al. 1979) when a feedingstuff was incubated with rumen fluid in vitro.

2. NH3 liberated during incubation is in part used for microbial protein synthesis. Production of carbon dioxide and methane can be regarded as a measure of energy available for protein synthesis. The ratio, gas production: incorporation of NH3-nitrogen was estimated by addition of starch to the substrate. The response in gas production was linear in the range 0–200 mg starch, when starch was added to 0–200mg feedingstuff dry matter and 30 ml rumen fluid-medium mixture.

3. Linear regression between NH3-N concentration (y, mg) and gas production (x, ml) yielded an intercept (b0) representing that amountof NH3-N which would be released when no fermentable carbohydrates were available and consequently no bacterial protein synthesis took place.

4. The difference between this intercept b0 and NH3-N content in the blank (rumen fluid without substrate added) indicated the amount of NH3 liberated from protein and other N-containing compounds of the feedingstuff incubated. In vitro-degradable N (IVDN) was calculated as a proportion of total N by the equation:
Effects on liver and serum lipids of dietary supplements of methionine and excess lysine given to previously-starved rats
Authors: Aoyama Yoritaka , Sakaida Kazuhiro , Yoshida Akira , Ashida Kiyoshi
Published: June 2005

1. The addition of lysine hydrochloride (50 g/kg) to a diet supplemented with methionine (3 g/kg) had no effect on liver lipids when rats (Wistar and Sprague-Dawley) were fedad lib.for 14 d. However, refeeding a diet supplemented with methionine and excess lysine hydrochloride to previously-starved rats (Wistar) for 6, 7 or 9 d, but not 3 or 4 d, resulted in liver lipid accumulation, mainly triglycerides, which was prevented by the addition of arginine, citrulline, ornithine, adenine, allopurinol or maize oil, but not by guanine, cytosine, thymine or uracil.

2. The addition of lysine hydrochloride to a methionine-supplemented diet resulted in reduced serum triglyceride levels after refeeding for 3 or 4 d and reduced serum cholesterol levels after refeeding for 3, 4 or 6 d. Serum lipids were unaffected by refeeding the diets for 7 or 9 d.

3. Since hepatic lipid accumulation was preceded by the decline in the level of serum triglycerides, one of the factors responsible for lipid accumulation in the liver might be reduced transport of triglycerides from the liver into the blood.

4. When adenine and allopurinol were added to the diet supplemented with methionine and lysine hydrochloride refed for 4 d, there was an increase in serum triglycerides. However, when this diet was refed for 7 d, with the addition of arginine, citrulline, guanine, pyrimidine bases, allopurinol or maize oil, no effects on serum cholesterol and triglyceride levels were observed.
Effects of ruminant digestion and metabolism on phenolic monomers of forages
Authors: Jung Hans-Joachim G. , Fahey George C. , Merchen Neal R.
Published: June 2005

1. Immature and mature lucerne (Medicago sativa) and tall fescue (Festuca arundinacea) hays were analysed for their lignin and phenolic monomer (hydroxybenzoic and hydroxycinnamic acid derivatives) contents. These hays were given to four sheep with rumen, duodenal and ileal cannulas, and to a steer with rumen and abomasal cannulas, to investigate the extent and sites of digestion of lignin and phenolic monomers.

2. The hays and digesta samples were analysed for alkali and nitrobenzene-extractablephenolic monomers. Lanthanum oxide was used as an external marker in the digestion studies. Urine was also collected for estimates of total phenolic balance.

3. Grass hays contained greater concentrations of alkali-labile phenolic monomers than did legume hays, whereas legume hays had higher levels of nitrobenzene oxidation products. Mature tall fescue hay had greater concentrations of phenolic monomers than did immature tall fescue hay, but corresponding differences with maturity were not observed with lucerne hays.

4. There were quantitative differences between diets in the digestibilities and in the sites of digestion of phenolic monomers. Digestibilities ranged from 0·191 to 1·004 for alkali-labile compounds and from −1·137 to 0·868 for nitrobenzene oxidation products. Composition of lignin was altered during its passage through the digestive tract. The proportion of phenolic monomers not recovered in urine and faeces varied from −1·014 to 0·871 for individual compounds and differed between diets. Soluble phenolic monomers decreased in concentration as digesta passed from the rumen to the abomasum and duodenum, but increased again in the ileum; levels varied with diet. Phenolics were rapidly solubilized in the rumen after feeding.

5. Results indicate that forages differ in their phenolic monomer content and in the digestibility of these compounds. Therefore, lignin is not an inert compound in the digestive tract of ruminants as has been previously reported.
Voluntary food intake of growing pigs given diets containing rapeseed meal, from different types and varieties of rape, as the only protein supplement
Authors: Lee Pauline A. , Hill R.
Published: June 2005

1. The voluntary food intake, during 30 min periods after morning and afternoon feeds and during 24 h, by growing pigs given diets containing rapeseed meal (Rsm) or soya-bean meal (Sbm) as the only protein supplement was determined. One diet was offered at a time and a daily changeover sequence of feeding was followed.

2. Four rapeseed meals were compared, one from seeds of British-grown winter Brassica napus varieties (Brsm) and the others from seeds of the var7ieties Tower (Trsm), Erglu (Ersm) and Span (Srsm). The effects on feed intake of adding flavouring substances to the Brsm diet were also determined. The flavouring substances were molassine meal, sucrose and four commercially-available substances: P, pig nectar; H, hog nectar; S, sow nectar and A, apple.

3. Intake of the Brsm diet was significantly less than those of the Sbm, Trsm and Ersm diets.

4. Addition to the Brsm diet of molassine meal or sucrose at 50 or 100 g/kg did not improve voluntary feed intake. None of the commercial flavouring substances raised the intake of the Brsm diet to the level of the Sbm diet but they improved intake of the Brsmdiet to varying extents. Flavourings H, S and A gave similar improvements which were substantial.

5. The Sbm, Brsm and Trsm diets were each fed ad. lib. to groups of growing pigs continuously for 4 weeks. Weekly feed intakes and weight gains were determined. Feed intakes and weight gains followed closely the intake values obtained in the changeover experiments. The highest values were for the Sbm diet; those for the Trsm diet were slightly lower and those for the Brsm diet were substantially and significantly lower.

6. The glucosinolate, sinapine and tannin contents of the rapeseed meals were determined and the results suggested that voluntary feed intake of diets containing these meals was related to their glucosinolate content, but not to their sinapine or tannin contents.
Effect of dietary fats on the δ6- and δ5-desaturation of fatty acids in rat liver microsomes
Authors: Kirstein D. , Høy C.-E. , Hølmer G.
Published: June 2005

1. Rats were given diets containing (% dietary energy): 46 arachis oil (AO), 36 partially-hydrogenated arachis oil (HAO) + 10 AO, 36 partially-hydrogenated marine oil (HMO) + 10 AO, or 46 of a combination of rape-seed oils high and low in erucic acid (RSO + LERSO).

2. In the liver microsomes the content of arachidonic acid (20:4ω6) was reduced inthe groups given HAO + AO and HMO + AO.

3. The rates of Δ6-desaturation of linoleic acid into γ-linolenic acid (18:3ω6) and of Δ5-desaturation of dihomo-γ-linolenic acid into arachidonic acid were studied in vitro at two substrate levels: a high substrate level reflecting maximal microsomal desaturase activity in rat liver and a low substrate level reflecting desaturase activity under physiological conditions.

4. Dietary HAO, rich in 18:1 isomers, suppressed the Δ6-desaturase activity butnot the Δ5-desaturase activity. Dietary HMO, rich in 18:1, 20:1 and 22:1 isomers, reduced both Δ6- and Δ5-desaturase activities.