Showing papers by "Rowett Research Institute published in 1971"

The cellulase of Fusarium solani. Purification and specificity of the β-(1→4)-glucanase and the β-d-glucosidase components

Abstract: 1. Cell-free culture filtrates of the fungus Fusarium solani were examined for homogeneity with respect to β-d-glucosidase and Cx activities. 2. o-Nitrophenyl β-d-glucoside and cellobiose were both used as substrates for β-d-glucosidase activity. 3. No evidence for the non-identity of nitrophenyl β-d-glucosidase and cellobiase activities could be found, either by heat treatment, gel filtration on Sephadex G-100 or by isoelectric focusing. 4. The β-d-glucosidase component was also a feeble exo-β-glucanase: it had a molecular weight of approx. 400000. 5. The fall in viscosity of a solution of CM-cellulose, the formation of reducing sugars in a solution of CM-cellulose and the solubilization of phosphoric acid-swollen cellulose (Walseth cellulose), were all used for the measurement of Cx activity. 6. The ratio of the two types of CM-cellulase activity was not changed after gel filtration on Sephadex G-100 or after chromatography on DEAE-Sephadex. 7. Three peaks of Cx activity were obtained after electrofocusing, but all three possessed the same ratio of the two types of CM-cellulase activity as well as the same CM-cellulase/Walseth activity ratio, as the unfractionated enzyme; all three isoenzymes (isoelectric points, 4.75, 4.80–4.85 and 5.15) acted in synergism with a mixture of the C1 and the β-d-glucosidase components to the same extent in the solubilization of cotton fibre. 8. The molecular weight of the Cx component was approx. 37000.

Digestion of concentrates in sheep. 4. The effects of urea on digestion, nitrogen retention and growth in young lambs.

Abstract: 1. The effects of adding increasing supplements of urea to mainly barley diets for early-weaned lambs were investigated in two experiments. In the first experiment the passage of nutrients along the alimentary tract was studied by taking samples of abomasal, ileal and rectal contents and using a marker technique. In the second experiment, feed consumption and rate of gain were recorded over the growth period up to 40 kg live weight, and nitrogen balances were carried out. In the second experiment a barley-fish meal diet was also included.2. The fermentation of organic matter in the rumen increased with the amount of urea in the diet and levelled off when the diet contained about 12% crude protein.3. Urea supplementation had significant effects in increasing N retention and rate of live-weight gain and in decreasing feed conversion ratio, but supplementation beyond about 12% crude protein in dry matter had no further effect on these measurements. In each instance results with the barley–fish meal diet were better than the results with any of the barley-urea diets.4. From the concentrations of diaminopimelic acid (DAPA) in abomasal fluid it was estimated that microbial protein was produced in the rumen at a rate of 15.6% g/100 g organic matter fermented. This ratio did not appear to alter significantly with urea supplementation, but the comparison depends on the assumption that the concentration of DAPA in the bacterial protein did not itself change with urea supplementation.5. Using results from both experiments, it was calculated that the retained N on the urea-supplemented barley diets was approximately 47% of the amount of protein N absorbed in the small intestine.6. It is suggested that barley diets for early-weaned lambs can with advantage be supplemented with non-protein N to increase the crude protein in the dry matter up to about 12%. When barley diets are given with a protein supplement the addition of non-protein N is unlikely to be beneficial unless the protein supplement is given in such a way that it is not subject to degradation to yield ammonia in the rumen.

The effect of the absence of rumen ciliate protozoa on growing lambs fed on a roughage-concentrate diet.

Abstract: 1. Lambs were removed form their dams at 2 d of age, and at 5 weeks of age eitht of one group were incoulated with a mixed rumen ciliate and seven in a second group were maintained ciliate-free throughout the 61 weeks of the experiment. Performance of the groups was compared when given a 2:1 roughage:concentrate diet as a set ration and with ad lib. roughage.2. Mixed ciliate populations developed in all faunated lambs and average-sized populations were maintained. Large numbers of flagellate protozoa developed in the ciliate-free animals after flagellates had been introduced into the building with the ciliate-free animals after flagellates had been introduced into the building with the ciliate inoculum.3. Higher numbers of rumen bacteria were found in the ciliate-free group.4. Only between the 14th and 21st weeks was there a significant different between groups in weight gain and this was infavour of the faunated group. The only significant different in body measurements was greater girth in the ciliate-free lambs.5. Only minor differences were found between the groups in calorimetric trials, digestibility and nitrogen balanes. There were no differences between groups in concentration of total protein N and soluble sugar in the rumen. The ammonis concentration was significantly higher in the faunated group.6. The concentrations of total rumen volatile fatty acids (VFA) were higher in the faunated group. Differences, between groups, in proportions of VFA were attributed to the activity of the rumen bacteria rather than the ciliates per se.7. No differences between groups were found in the concentrations of blood sugar and haemoglobin.8. It was concluded that the changes due to the presence of rumen ciliates were not great enough to be reflected in animal performance under the conditions of this experiment.

The nutrition of the early weaned lamb:III. The effect of ad libitum intake of diets varying in protein concentration on performance and on body composition at different live weights

Abstract: 1. Fifty lambs weaned at about 5 weeks of age were fed ad libitum on mixtures of barley and fish meal containing either 11·0, 15·7 or 19·4% crude protein in dry matter. Male and female lambs on each diet were killed at intervals, starting after they had been on the diets for 3 weeks. The last to be killed had attained a live weight of about 55 kg.2. The mean rate of voluntary feed consumption was less at all live weights for the lambs on the diet containing 11·0% crude protein than for those on the other diets and the difference was statistically significant at live weights of 30 and 35 kg. Mean rates of live-weight gain on the low, medium and high protein diets were respectively 191, 270 and 330 g per day for the male lambs and 177, 225 and 301 g per day for the females, the increase with protein concentration being highly significant. Feed conversion rate (kg feed/kg gain) over the whole experiment increased with increasing weight at slaughter. After adjustment for this effect the mean values showed significant dietary effects, and were least on the highest protein concentration.3. The percentages (y) of nitrogen or of ether extract in the dry matter of the carcass or of the whole empty body were found to be related non-linearly to the empty-body weight (x) at time of slaughter. The relationships were satisfactorily described by equations of the form y = A + Be-Cx, where A, B and C were fitted constants. The relationships for males and females had to be fitted separately, but a common value of A could be used with each of the three groups of male lambs and similarly for the three female groups.4. These relationships were used to obtain estimates of the nitrogen, ether extract and energy content of empty-body gain per unit live-weight gain. The estimated percentages of energy retained as fat were of the order of 76–83%, in agreement with ARC estimates (1965), except for male lambs between 14 and 20 kg live weight on medium or high-protein diets, for which the estimates were only 62 and 63%.5. The implications of these relationships are discussed with particular reference to the finding of dietary effects on body composition during the growth period of the lambs and to the tendency for these differences in body composition to diminish as mature live weight was approached. The differences in body composition between male and female lambs showed no such tendency to diminish.

The digestion of bacterial mucopeptide constituents in the sheep. 1. The metabolism of 2, 6-diaminopimelic acid

Abstract: 1. In a series of experiments with cannulated lambs the amounts of 2, 6-diaminopimelic acid (DAPA) and a-amino nitrogen passing daily through the abomasum, terminal ileum and rectum were measured. While there was a very significant net absorption of α-amino nitrogen between the abomasum and terminal ileum, there was no net absorption of DAPA between these points. Indeed, there was a tendency for more DAPA to leave the terminal ileum than entered the abomasum, though this was only significant at the 10% level. In all cases significantly less DAPA passed out of the rectum than passed through the terminal ileum, indicating extensive degradation of this amino acid in the hind-gut, probably as a result of microbial activity. 2. In adult sheep given control rations no DAPA could be detected in the blood, even when 643 ml plasma were analysed. These sheep usually excreted less than 5 mg DAPA daily in the urine. 3. When synthetic DAPA was introduced into the peritoneum, blood, abomasum, rumen or caecum of cannulated adult sheep in physiological amounts, approximately 80, 83, 53, 5 and 0 % of the administered dose was recovered in the urine. Furthermore, when introduced into the abomasum, DAPA could be measured in plasma from the anterior mesenteric and jugular veins. 4. It was concluded that in the normal sheep the DAPA-containing fraction of the bacterial cell-wall material synthesized in the rumen is not digested in the small intestine. In the caecum and colon, however, this fraction is extensively degraded by hindgut bacteria.

The effects of environmental temperature on the growth and metabolism of pigs given different amounts of food. 1. Nitrogen metabolism, growth and body composition.

Abstract: 1. Twelve castrated male pigs were kept at each of three temperatures and given food at one of three levels of intake. The temperatures and daily food intakes (expressed as g/kg 0.73 ) were 23° (80, 100, 120), 13° (100, 120, 140), 3–5° (120, 140, 160). Growth and nitrogen metabolism were measured during growth from 20 kglive weight until slaughter at gokg live weight, when the body contents of N and fat were estimated. 2. Growth rate increased with each unit of daily food intake (I g/kg 0.73 live weight) by 7.73 ± 0.74 g/d. This value did not vary significantly with temperature. Daily growth rate was depressed by 17.8 ± 2.3 g for each I° fall of temperature. 3. Daily N retention estimated by the balance method exceeded by 2.59 g/d that estimated by the comparative slaughter technique. Both results led to the same conclusion, which echoed that found with growth rate, that there was no significant effect of temperature on the response of N retention to increasing food intake. Taking the mean of the two estimates, N retention at a constant food intake fell by 0.38±0.055 g/d for each I° fall of temperature. 4. The N content of the ingesta-free carcass at slaughter fell with each increase in daily food intake by 0.007±0.002%, and the fat content rose correspondingly by 0.116±0.027%. These regressions did not vary significantly with temperature. When considered at a constant food intake, body composition did not alter significantly with temperature.

Relative palatability to sheep of straw, hay and dried grass.

Abstract: 1. In the first of two experiments four sheep were fed on dried grass and oat straw in the following combination: (1)straw eaten to appetite and an equal quantity given via a rumen fistula, (2)straw eaten and grass by fistula, (3)grass eaten and straw by fistula, (4)grass eaten and grass by fistula. Mean daily dry-matter intakes (g/kg metabolic live weight, W0·75) for the four treatments respectively were: 13·3, 23·2, 47·8 and 59·4. Dry-matter digestibility coefficients (%) were 37·2, 53·1, 53·3 and 71·3. Changing the digestibility of the diet without changing the component eaten (1 v.2; 3v.4) had a large effect on intake, but changing the component eaten without changing digestibility (2v. 3) caused a twofold change in intake. The latter result implied a difference in palatability between the feeds.2. The quantities of digesta in the rumen, determined by removal before and after feeding, were generally twice as great for treatments 3 and 4 as for 1 and 2. There were corresponding differences between treatments in the rates of passage of stained particles of feed and of chromic oxide.3. In the second experiment the treatments were the same except that meadow hay replaced oat straw. Mean daily dry-matter intakes (g/kg W0·75) were 41·7, 55·1, 59·9 and 68·7 for treatment 1 to 4 respectively, and digestibility coefficient were 54·0, 61·3, 62·3 and 72·0. In this experiment there appeared to be only a small difference in the palatability of the feed.

The effects of nitrogenous fertilizer on the nutritive value of artificially dried grass.

Abstract: 1. A field trial in which a sward, predominantly of S. 24 ryegrass was fertilized with 248, 301, 532 or 589 kg N/ha showed that a maximal yield of 13·1 tonnes/ha of artificially dried grass could be obtained from four harvests in the year. 2. The materials harvested ranged in crude protein content from 10·1 to 23·6% and in apparent digestibility of dry matter from 72 to 76%. The amounts of the grasses voluntarily consumed by sheep were slightly and significantly lower for those containing the least N × 6·25. 3. In feeding trials with twenty-five steers, a barley diet was compared with a diet entirely of dried grass from the 3rd and 4th harvests from an area in the same field which had received 487 kg N/ha. The cattle given the barley diet consumed 8·7 kg/day and gained 1·22 kg/day. Those given dried grass consumed 8·9 kg and gained only 0·85 kg/day. Carcass quality of animals given dried grass was significantly lower than of those given the barley diet. 4. Calorimetric trials were made using two herbages from the first harvest (501, 532 kg N/ha) and all four herbages from the third harvest. In each of the six experiments three sheep were each given three amounts of a herbage, and in addition were fasted. Fifty-four calorimetric observations each lasting 5 days and eighteen fasting metabolism measurements were made. 5. With both 1st and 3rd harvests, methane energy losses fell and urinary energy losses increased with the level of N fertilization. Faecal energy losses were little affected by fertilizer application and the metabolizable energy (kcal/g D.M.) was 2·8 (11·7 kJ/g) for 1st harvests and 2·6 (10·9 kJ/g) for 3rd harvests. There was a slight decline in metabolizable energy/g D.M. with N application for the 3rd harvests. 6. The net energy values of the grasses for maintenance were 1·99 kcal/g D.M. (8·4 kJ/g) for the 1st harvested material and 1·84 kcal/g D.M. (7·7kJ/g) for the 3rd harvests. Net energy values for fattening, however, were 1·28 kcal/g D.M. (5·4kJ/g) for 1st harvests and 0·87 kcal/g D.M. (3·6kJ/g) for 3rd harvests. There were no significant effects of level of N fertilization. 7. The poorer nutritive value for fattening of the 3rd harvested grass, corresponding to an efficiency of utilization of metabolizable energy of only 33%, was contrary to prediction from equations relating nutritive value to either chemical composition or to metabolizable energy. The results of the calorimetric work, however, agreed with those of the feeding trial with cattle. 8. Combination of the results of the various trials showed that it was possible to obtain 1400 kg live-weight gain/ha from a system of husbandry based on high fertilizer use and artificial drying of herbage. With a barley system a maximal output/ha would be less than half this amount.

Digestion of concentrates in sheep. 1. The effect of increasing the concentration of soya-bean meal in a barley diet on apparent disappearance of feed constituents along the digestive tract.

Abstract: 1. Four sheep were given four diets containing proportions of rolled barley and soya-bean meal varied to provide 10.3, 13.3, 16.1 and 19.9% crude protein in the dietary dry matter; the treatments were given according to a 4 x 4 Latin square design. The mean daily intake was 989 g dry matter. The apparent disappearance of protein, ash, ether extractives and carbohydrate before the abomasum, between the abomasum and terminal ileum and between the terminal ileum and rectum was measured.2. The amount of non-ammonia crude protein (Y1, g/d) disappearing from the small intestine increased with protein intake (X, g/d) according to the equation Y1 = 2.12X – 0.0057X2–83, reaching a maximum when there was about 19% crude protein in the dry matter of the diet.3. The treatments had no significant effects on the disappearance of starch, ether extractives or ash. About 93% of starch disappeared in the rumen and 6% in the small intestine. The total mean daily intake of ether extractives was 21 g; 9 g were added in the rumen, 24 g disappeared from the small intestine and 6 g were excreted in the faeces. The total mean daily intake of ash was 67 g; 26 g were added in the rumen, 37 g disappeared from the small intestine, 9 g from the large intestine and 47 g were excreted in the faeces.

Some preliminary observations on the nature of factors influencing the excretion of non-dietary faecal nitrogen by ruminant animals

Abstract: SUMMARY 1. When roughage rations of medium to high quality were given to steers and aduit sheep, the excretion of non-dietary faecal nitrogen was positively related to the intake of truly digestible dry matter. In these experiments no significant relationships were noted between non-dietary faecal nitrogen excretion and the intake of either truly digestible nitrogen or truly indigestible dry matter. 2. When concentrate rations containing 1.6–3.2% nitrogen were given to lambs weighing 19–27 kg the excretion of non-dietary faecal nitrogen was positively and significantly related to the intake of both truly digestible dry matter and truly indigestible dry matter, but not related to the amount of truly digestible nitrogen consumed. 3. Grinding and pelleting a grass ration for steers resulted in an increase in the excretion of non-dietary faecal nitrogen and bacterial + endogenous debris nitrogen, of 28 and 30% respectively, compared with the chopped material. 4. It is concluded that these responses reflect the dominating influence of nitrogen of microbial residues from the rumen and hind-gut on the excretion of bacterial + endogenous debris nitrogen and non-dietary faecal nitrogen.

Changes in proteolytic enzyme activities and transformation of nitrogenous compounds in the germinating seeds of kidney bean (Phaseolus vulgaris)

Abstract: Hydrolytic activity towards synthetic substrates and denatured proteins was measured in the extracts of the seeds of kidney bean at various stages of germination up to 16 days. Of the peptide hydrolases, chymotrypsin-type activity was stable for the first 7 days, then rapidly increased towards the end; leucine aminopeptidase activity decreased to a minimum (8th day) then slowly increased again; trypsin-type activity remained constant throughout. Proteolytic and autodigesting activities showed an optimum between pH 5.0 and 5.5. Both activities decreased slowly first, then rose to a sharp maximum at the 8th day. The haemoglobin-digesting activity after a minimum increased again at the 14th day. The autodigesting activity had an additional maximum. Concomitant with these changes, non-protein nitrogen increased twofold by the 5th day, remained constant up to the 12th day and then increased again. Protein content on the other hand decreased first, had a maximum at the 9th day after which it steadily decreased again. The amounts of albumins and globulins changed independently of each other: albumins decreased continuously with the exception of a steady period (5–9th days), while globulins were more stable except for a sharp minimum (6–7th days) and a steady decrease after the 13th day.

Studies on the digestibility and utilization of the nitrogen of irradiated rumen bacteria by rats.

Abstract: Rumen bacteria were isolated from the rumen contents of eight Friesian cattle that had been fed a barley-soyabean diet. These preparations were freeze-dried, irradiated with 1 Mrad and analysed for various nitrogenous components. In nitrogen utilization studies involving both young and adult rats it was observed that the ‘true’ digestibility of the bacterial nitrogen was about 80%, while the net protein utilization (NPU) value was approximately 57. It was concluded that about 20% of the bacterial nitrogen, mainly incorporated in the cell wall, was not absorbed by the rat. On the other hand, about 71% of the absorbed nitrogen was utilized by the growing rat for tissue synthesis. Irradiation with 1 Mrad killed virtually all the rumen bacteria without adversely influencing the nutritional value of the bacterial protein.

The effect in an intensive production system of type of cereal and time of weaning on the performance of lambs

Abstract: Two experiments were conducted to study the effect of type of cereal and time of weaning on the performance and voluntary intake of lambs.In the first experiment 20 early-weaned entire male lambs were given diets ad libitum during the fattening period from 15 to 40 kg live weight. The diets were based on either kibbled maize or rolled barley. A high feed efficiency and growth rate were achieved with both diets and differences between them were not statistically significant. The growth rates were 428 and 430 g/day. The cold carcass weights at 40 kg live weight were 19·0 and 19·9 kg and the conversion ratios of dry matter to live-weight gain were 2·33 and 2·22 for the rolled barley and kibbled maize diets respectively.In the second experiment a comparison was made of the performance of 36 sets of twin lambs, one of each set being weaned at either 6, 13 or 20 weeks of age and the other being left to suck the ewe outdoors. The lambs weaned at 6 weeks had better conversions of dry matter to live-weight gain than lambs weaned at 13 and 20 weeks. The respective conversions of dry matter to live-weight gain were 3·36, 5·64 and 5·52. The lambs weaned at either 13 or 20 weeks had a greater weight at weaning, a greater growth check at weaning and a lower rate of feed intake.

Copper and molybdenum in subcellular fractions of rat liver.

Abstract: 1. Black-hooded weanling rats were given a copper-deficient diet or diets providing 3 ppm Cu with or without supplements containing combinations of molybdate, sulphate and sulphide salts to provide 35 ppm molybdenum and 2μg atoms sulphur/g. Changes in weight and blood haemoglobin concentration were studied during 48 d of treatment. The subcellular distribution of Cu and Mo in the liver was subsequently determined. 2. Rats fed on the Cu-deficient diet had a lower growth rate than animals receiving 3 ppm Cu and suffered a decline in blood haemoglobin concentration; Mo supplementation of the diet providing 3 ppm Cu produced similar adverse effects on growth but not on Hb. Effects of Mo on growth were exacerbated by a sulphide supplement which also decreased the rate of the gain in Hb concentration. This concentration of dietary sulphide was without effect when Mo was omitted from the diet. 3. The Cu-deficient diet decreased both the Cu concentration and proportion of total liver Cu in mitochondria + microsome and supernatant fractions of liver. 4. Mo-supplemented diets greatly increased both the Cu and Mo contents of all liver fractions. This phenomenon is considered in relation to previous suggestions that an unavailable Cu–Mo complex can form in tissues as a response to Mo accumulation.

The digestion of bacterial mucopeptide constituents in the sheep. 2. The digestion of muramic acid

Abstract: 1. In experiments with four lambs cannulated in the abomasum and terminal ileum the amounts of muramic acid, diaminopimelic acid and α-amino nitrogen passing through the abomasum, terminal ileum and rectum were compared. While the concentration of muramic acid and diaminopimelic acid was higher in the ileal than in the duodenal dry matter, the ratio of muramic acid to diaminopimelic acid remained fairly constant at about 1·00:0·86 on a molar basis. 2. There was a very significant net absorption of α-amino nitrogen between the abomasum and terminal ileum, but no net absorption of muramic acid between these points. However, less muramic acid passed out of the rectum than passed through the terminal ileum. 3. It was concluded that in the normal sheep bacterial mucopeptide synthesized in the rumen is not digested in the small intestine, but is extensively degraded by bacteria in the caecum and colon.

The effect of pattern of food intake in pregnancy upon sow productivity.

Abstract: Seven research and teaching centres have co-operated in an experiment involving 154 sows. The experiment compared the effect of feeding four different patterns of feed intake during pregnancy upon reproductive performance of sows. In each case approximately 220 kg of feed were given during each gestation according to four patterns of intake designated Constant (C), Low-High (L-H), High-Low (H-L) and High-Low-High (H-L-H). During lactation all animals were given a daily ration of 3·7 kg of feed for litters of five pigs or less, and 0·4 kg for each additional piglet. Wherever possible the sows remained on the same nutritional regimes for three parities.Although the pattern of feed intake slightly affected the live-weight changes of the sows during the course of pregnancy, the treatments had no significant effects on overall change in weight of the sows in pregnancy or in lactation in any of the three parities. The live weights of the sows at the end of the third parity were very similar for all treatment groups.The patterns of feed intake had no appreciable or significant effect on the numbers of pigs born, their average weight at birth or upon the numbers of pigs which survived to weaning at 6 weeks or their live weight. The health and breeding regularity of the sows were also unaffected by the treatments.There were differences between the centres in many of the variables which were compared, but there was no evidence of any important centre × treatment interactions.It is concluded that, at the levels of intake given in pregnancy and lactation in this experiment, there are no beneficial or detrimental effects of changing the pattern of intake during pregnancy.

Renal excretion of acid in calves fed either roughage or concentrate diets.

Abstract: Calves fed a roughage diet (50 per cent hay + other components) excreted an alkaline urine rich in bicarbonate but poor in phosphorus Infusion of HCl into the rumen led to a fall in urine pH, to a decrease in bicarbonate excretion and to the excretion of acid in the urine Between 16–25 per cent of this acid was excreted as acid phosphate (H2PO4-) and the remaining 75–84 per cent as ammonium ions In contrast, when the calves were fed a concentrate diet (85 per cent barley + other components) the urine was acid and contained appreciable amounts of phosphorus and ammonium ions Infusion of HCl into the rumen produced a further increase in acid excretion, practically all of which appeared in the urine as ammonium ions Excretion of calcium in the urine increased during infusion of HCl and was correlated with urine pH There were few changes in faecal mineral excretion during acid infusion but less sodium and potassium were excreted in the faeces when the concentrate diet was fed compared to when the roughage diet was fed

A comparison of digestion in red deer and sheep under controlled conditions.

Abstract: Three red deer hinds and three sheep were given rations of chopped or pelleted hays. The deer apparently digested dry matter and cellulose a little less well than the sheep. Digestibility of nitrogen did not differ. In two pairs of animals fitted with rumen cannulas the volume and outflow of rumen fluid was greater in the deer than in the sheep. The pH and the concentrations of total and individual volatile fatty acids and of ammonia in the rumen fluid varied during the feeding cycle in much the same way in the deer and sheep. The rumen fluid of the deer seemed to be a little less well buffered than that of the sheep. It is concluded that digestive processes in the deer, as far as revealed in these experiments, quite closely resemble those in the sheep, though certain small differences may exist.

Moist barley for growing pigs: some effects of storage method and processing.

Abstract: Forty-eight pigs were used to compare the feeding value of barley which had been stored dry, and then hammer-milled, with that of barley stored moist, either anaerobically or treated with 1·3% propionic acid, and then rolled. The pigs were fed from 30 kg live weight for a period of 11 weeks and during this period all consumed the same allowance of dry matter. The growth rate and feed conversion ratio of the pigs given the rolled moist barley were significantly poorer than those of others given dry milled or acid treated rolled barley. There were no treatment differences in carcass attributes.Microbiological counts made throughout the experiment showed that there was no significant fungal or bacterial development on the acid treated barley. Similar numbers of bacteria were present on the dry barley as on the moist, but the fungal count for the moist grain was always at least 500 times higher than that of the corresponding dry sample. The dominant organisms were identified.In a further experiment the apparent digestibility of dry matter and nitrogen of diets containing dry, moist or propionic acid treated barley, processed either by milling or rolling, were determined. The highest values were obtained for dry barley. Acid treated moist barley had lower values than moist barley. The method of processing did not affect the apparent digestibility of the dry matter, but that of the N was significantly lower for the rolled barleys.

The non-protein nitrogen composition of grass silage:III. The composition of spoilt silages

Abstract: SUMMARY The nitrogenous composition of the water soluble, non-protein nitrogen fractions of three samples of high-pH-spoilt silage and one sample of overheated silage were examined in detail. The amino acid nitrogen content of the high-pH-spoilt silages declined with increasing extent of spoilage, due to a selective degradation of the amino acids. Losses of amino acids were associated with proportionate increases in the amount of volatile basic nitrogen. Lower aliphatic amines were not present and it was therefore concluded that the ultimate end product of nitrogen metabolism in high-pH-spoilt silages was ammonia. Only low concentrations of putrefaction products, such as putroscine, cadaverine and histamine were present. The composition of the non-protein nitrogen fraction of the overheated silage was unusual in that the ammonia nitrogen content was high and associated with the complete destruction of certain amino acids. The free amino acid nitrogen content was low but this was partially compensated for by a very high ‘peptide’ nitrogen content. There was no evidence of putrefaction products in this silage.

Fractionation and characterisation ofj water‐soluble polysaccharide‐protein complexes containing hydroxyproline from the leaves of Vida faba

Abstract: The water-soluble polysaccharide-protein complexes obtained previously by extraction with aqueous trichloroacetic acid and by phenol-aqueous (pH 8) partitioning from the leaves of Vicia faba were fractionated into a number of components by continuous high voltage electrophoresis at pH 8.3 and 3.97 and by Sepharose 4B chromatography. The results indicated that these materials contained a spectrum of molecules with rather similar properties. All fractions obtained contained about 4–7% (wlw)lightly bound protein, two-thirds of which was made up of four amino acids: hydroxyproline, alanine, serine and threonine. Similarly, all materials contained uronic acid (10–70%; w/w)and neutral sugars (10–90%; w/w), mainly arabinose and galactose. High uronic acid content was found to be associated with appreciable rhamnose content and an arabinose-galactose ratio close to 2. This ratio became about 0.3 when the amount of uronic acids decreased to about 10% (w/w).

Problems in the determination of the trace element requirements of animals.

Abstract: Statements of the trace element requirements of man and domesticated animals have appeared in publications of the (US) National Research Council (1960, 1964, 1966, 1968a, b, I ~ o ) , the (UK) Agricultural Research Council (1963, 1965, 1967) and in authoritative reviews such as those of Underwood (1962, 1966). In presenting these statements the authors repeatedly emphasize the provisional nature of their conclusions, the many factors which limit the value of a single statement of requirement and the scarcity of published information relating physiological performance to trace element intake. This review examines some of the practical problems behind the determination of trace element requirements and considers the value and limitations of statements of requirement under practical and experimental conditions. Several different approaches have been employed to assess trace element requirements, namely ( I ) studies of relationships between dietary concentration and physiological response, (2) studies of input/output relationships in balance trials, (3) factorial assessments of requirements based upon body composition studies coupled with estimates of endogenous excretion, (4) estimates derived from the analysis of field data obtained in association with studies of suspected deficiency disorders. Each of these approaches is subject to hazards of execution and interpretation and, undoubtedly, the greatest among these are the the problems caused by adventitious contamination during the conduct of the experiment.

Evidence for a role of cyclic AMP in the release of calcitonin.

Abstract: Calcitonin is a polypeptide hormone of 32 amino acids secreted by the C-cells of mammalian thyroid and from the ultimobranchial glands of lower species. The hormone is stored within granules from which it can be released by hypercalcemia. Calcium ions have been shown to be involved in the stimulation of secretion of a number of hormones such as insulin,' in which cyclic AMP is also thought to be involved.2 It was therefore decided to investigate the possibility of cyclic AMP involvement with calcitonin secretion and to identify any hormones which might be capable of activation of C-cell adenyl cyclase.