1. A study was conducted in two centres in southern and northern India of the effects of the addition of ascorbic acid and protein supplements to iron, pteroylglutamic acid and cyanocobalamin, in the prophylaxis and treatment of anaemia of pregnancy.

2. A dose of 500 mg ascorbic acid/d had no beneficial effect. Women who received 15 g calcium caseinate/d showed a superior haematological response. The reasons for this are unknown, but are more likely attributable to an increased absorption of the supplemental iron than to the correction of a protein deficiency.

1. The relative efficacy of oral and parenteral iron administration in the prophylaxis and treatment of Fe-deficiency anaemia of pregnancy has been studied.

2. Intravenous administration of Fe by total dose infusion of Fe dextran was not superior to oral Fe 120 mg/d, 6 d/week for 10–12 weeks.

3. Intramuscular Fe dextran, 100 mg twice per week for 10–12 weeks, produced a significantly greater rise in mean haemoglobin concentration than oral Fe therapy.

4. The superiority of intramuscular Fe as compared with intravenous Fe is probably related to the different handling of the Fe dextran by the reticulo-endothelial system.

5. In spite of the better response to intramuscular Fe dextran, it is not recommended for public health practice because of the risks associated with its use and the much higher cost of the preparation and its delivery.

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.

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.

1. Distribution of Nτ-methylhistidine (3-methylhistidine; Me-His) among organs and tissues in cattle was determined. From the amount of Me-His in skeletal muscle protein and daily urinary output of Me-His, fractional catabolic and synthetic rates of myofibrillar proteins of skeletal muscle during growth were calculated.

2. More than 93.4% of the total Me-His (35.6 mg/kg body-weight) in the analysed cattle tissues occurred in skeletal muscle protein. The amount of Me-His in tissues other than skeletal muscle was relatively small. Daily urinary excretion of Me-His in the cattle which were fed on hay and concentrate was 135 mg at a growing stage of 217 kg body-weight and 145 mg at a stage of 312 kg. The Me-His content of foodstuffs was also carefully checked in the present investigation. Assuming that absorbed dietary Me-His in quantitatively excreted in the urine without delay, the contribution of Me-His in foodstuffs was calculated to be approximately 30 % of the urinary Me-His. Rumen protozoa and bacteria contained little Me-His.

3. From these results, fractional catabolic and synthetic rates of myofibrillar proteins of the cattle at a growing stage of 217 kg body-weight were calculated to be 1.22%/d (half-life 56 d) and 2.73%/d, while these rates at a stage of 312 kg body-weight were 1.02%/d (half-life 67 d) and 1.51%/d respectively. These values were calculated on the same assumptions as those for the rat (Young et al. 1972; Funabiki et al. 1976). Of the Me-His present in foodstuffs 94% was tentatively assumed to be excreted into urine.

1. The calculated median daily trace element intakes /kg of exclusively-breast-fed infants at 1, 2 and 3 months of age respectively were: copper 0.075, 0.051 and 0.043 mg; iron 0.075, 0.055 and 0.048 mg; manganese 0.9, 0.6 and 0.5 μg; zinc 0.420, 0.215 and 0.150 mg. The latter values for Cu, Fe, and Zn intakes were in good agreement with earlier results, whereas the intake of Mn was lower. The intakes of trace elements by breast-fed infants seemed to be below the recommended dietary allowances (Food and Nutrition Board, 1973; WHO Expert Committee on Trace Elements in Human Nutrition, 1973).

2. There seems to be no information on trace element concentrations of breast milk related to the energy content. Such values are therefore included for breast milk from Finnish women for the 1st 6 months of lactation.

1. The effects of defaunation of the rumen of lambs given low-protein-high-energy diets were studied using animals fed ad 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.

1. Two experiments are reported. In both experiments a cereal-based diet containing 5 mg copper/kg was fed to two breeds of laying hens for 336 d. In Expt I four other groups were given this diet with the addition of CuSO4.5H2O to give added levels of 200, 400, 600 and 800 mg Cu/kg diet. In Expt 2 the levels of added dietary Cu used were 100, 200, 300 and 400 mg/kg.

2. In Expt I records were kept of food intake, water intake, body-weight and egg production for eight 28 d periods and body-weight and egg number only were recorded for the full twelve periods. In Expt 2 full records, excluding water intake, were taken for all twelve periods.

3. Food and water intake showed a quadratic response to level of added dietary Cu, being enhanced at lower levels and depressed at higher levels of addition.

4. There was a quadratic response of total egg weight, mean egg weight and egg number to added dietary Cu. In Expt I egg number was maximum at 235 mg added Cu/kg diet for Warren Studler SSL (breed I) and at 170 mg added Cu/kg diet for Shaver 288 (breed 2). In Expt 2 no breed effect occurred, the maximum egg number being calculated to occur at 176 mg added Cu/kg diet.

5. Depression of body-weight gain occurred at high lelvels of Cu addition. The depression of liver and oviduct weight found at high levels of addition appeared to be directly related to body-weight. A marked amount of feather loss also occurred at a high inclusion of CuSO4 in the diet.

6. The reproductive systems of the hens did not appear to be adversely affected at the levels of additive used. Gross and microscopic examination of specific tissues revealed no pathological effects although gizzard and intestinal weights were increased and caecal weight decreased by high levels of added Cu. Those aspects of the blood chemistry examined did not reveal any consistent effect between the two experiments.

7. The liver Cu analyses indicate that between 600 and 800 mg added Cu/kg diet liver Cu concentration rises sharply. Both liver Fe and Zn concentrations showed a positive linear response to added dietary Cu. In the kidney Cu and Zn concentrations were increased but only to a limited extent, while the concentration of Fe was unaffected.

1. The intake of zinc in the West of Scotland was determined by atomic absorption spectrometry, in ninety-six items of food which make up the local standard diet for 1 week.

2. The diet contained less Zn than the recommended daily allowance ((US) National Academy of Sciences, 1974). This finding either indicates the need for a revision of the suggested allowances or suggests that a change of diet is necessary.

3. The change could be made simply by the substitution of wholemeal flour for white flour. Other changes in diet were considered but they were unlikely to be acceptable. Even with changes the requirement of pregnant or lactating women would not be met. If the recommended allowances are valid these women must be deficient in Zn.

1. The minced carcases of twenty-seven lambs, ranging from 18 to 69 kg in live weight, and twenty-five calves (30–90 kg) were analysed for copper, iron, manganese and zinc. The lambs were weaned whereas the calves were reared exclusively on milk.

2. Mean concentrations of Fe, Mn and Zn for groups of lamb carcases fell within the ranges 52.6–75.1, 0.7–1.2 and 20.8–25.6 mg/kg fresh carcase weight respectively. The concentrations of Fe and Mn decreased while that of Zn increased slightly with age at slaughter. The concentrations of Fe, Mn and Zn in calves were close to thosein lambs.

3. For both species, the concentration of Cu in the carcase varied erratically: variation in hepatic Cu storage was implicated. In an additional study of ten full-term foetuses from Cu-depleted or Cu-supplemented ewes, a dietary Cu supplement (10 mg/kg dry matter (DM)) increased foetal Cu status 10-fold, due largely to an increase in foetal liver Cu.

4. The mean retentions of trace elements in the lamb carcases (%intake) were approximately: Cu 2.0, Fe 1.3, Mn 0.08, Zn 4.0. The corresponding values for the milk-fed calves were all probably much higher (Cu 23, Fe 43.7, Mn 4.9, Zn 34.0) but Cu intake was not accurately measured.

5. After allowing for tissue storage of Fe and Mn, values of 55, 0.85 and 24 mg/kg carcase gain were taken to represent the approximate net growth requirements of lambs for Fe, Mn and Zn respectively: the corresponding value for Cu was probably < 1.0 mg/kg. Values for calves were similar to those for lambs.

6. It was concluded that the total net requirements of ruminants for Fe and Zn shouldbe considered in terms of daily intakes of the metans rather than dietary concentrationsbecause of the relatively large and constant contribution of the growth component to thetotal requirement.

1. Seventeen pigs were fitted with single re-entrant cannulas in either the duodenum (posterior to the entry of the bile and pancreativ ducts), the mid-jejunum, or the terminal ileum. A further twenty-four pigs were used in a conventional digestibility trial.

2. Three diets were used: these contained barley, fine wheat offal, white fish meal, minerals and vitamins (diet BWF); starch, sucrose, maize oil, cellulose, minerals, vitamins and either groundnut meal (diet SSG) or casein (diet SSC).

3. The quantities of total carbohydrate (TC), total reducing substances (TRS) and glucose (G) passing through the re-entrant cannulas and excreted in the faeces in 24 h were measured. These were used to determine the net absorption of the carbohydrate fractions in the different regions of the intestine.

4. The small intestine was the principal site of absorption of TC, TRS and G, but there were differences between the diets in the quantities of each of these carbohydrate fractions that were absorbed in the different regions of the small intestine studied.

5. The quantities of TRS and G in solution were very low for all diets at all sites, indicating that the rate of absorption of the products of hydrolysis kept pace with their rate of formation.

1. Two experiments were conducted to investigate the effect of intestinal coccidiosis (Eimeria acervulina) on blood plasma and tissue ascorbic acid (AA) concentrations in chicks, and a third experiment was carried out to examine the role of dietary AA in this infection.

2. Experimental infection with intestinal coccidiosis (Eimeria acervulina) brought about a depletion in the concentration of AA in blood plasma, duodenum, jejunum, ileum, liver and the adrenal glands. Generally, these changes were obtained after the prepatent period of 4–5 d of the infection.

3. Dietary AA at 1000 mg/kg prevented the depletion in plasma and tissue AA levels but did not significantly affect adrenal weight.

1. The effect of varying protein intake at two energy levels of 334 and 418 KJ/kg body-weight was studied in four preschool children belonging to the low socio-economic group.

2. Results indicated a curvilinear relationship between N intake and N retention. From this relationship, the protein requirement of the children at adequate energy intake was calculated.

3. At adequate energy intake (418 KJ/kg body-weight) the protein requirement of the children was 1.33 g /kg. On decreasing the energy intake by 20% to 334 KJ /kg body-weight the protein requirement was found to be increased by 20% to 1.64 g/kg.

4. Based on this study, a safe level of protein intake for Indian preschool children subsisting on a diet based predominantly on vegetable proteins has been suggested.

1. Seventeen pigs fitted with single re-entrant cannulas in either the duodenum (posterior to the point of entry of the bile and pancreatic ducts), the mid-jejunum, or the terminal ileum, and a further twenty-four non-cannulated pigs were used.

2. Three diets were used: these contained barley, fine wheat offal, white fish meal, minerals and vitamins (diet BWF); starch, sucrose, maize oil, cellulose, minerals, vitamins and either groundnut meal (diet SSG) or casein (diet SSC).

3. The quantities of total lipid (TL), acid-detergent fibre (ADF) and volatile fatty acids (VFA) passing through the re-entrant cannulas and excreted in the faeces in 24 h were measured. These were used to determine the net absorption (or synthesis or secretion) in the different regions of the intestine.

4. There was substantial secretion of TL into the proximal small intestine and major absorption from the distal portion for all three diets. In the large intestine there was little or no further net absorption for diets SSG and SSC, but significant synthesis or secretion for diet BWF.

5. Fibre digestion occurred in both the small and large intestines and the apparent absorption of ADF in the different regions studied was influenced by diet.

6. There were detectable amounts of VFA at all sites but only at the ileum and in the faeces could they be accurately measured. Diet did not affect the molar proportions of acetate, propionate and butyrate in ileal digesta, but did have an effect on these VFA in the faeces.

1. Sheep equipped with rumen and abomasal cannulas were given ad lib. access to ground and pelleted lucerne (Medicago sativa) hay except for periods of up to 6 h immediately before experimental sessions in which food intake was measured while various stomach compartments were either distended or subjected to tactile stimulation from a probe.

2. Inserting a probe, consisting of two collapsed balloons tied onto the end of a polyethylene tube, into the reticulum depressed intake by 24% after 30 min of feeding (P < 0.025). Compensatory feeding was observed during the 30 min period immediately following removal of the probes. There were no effects of having a probe in the abomasum.

3. Distension of the reticulum with 0–800 ml water in a balloon depressed intake by 0.2 g/ml after 30 min of feeding (P < 0.05). Removing the balloons from the animals allowed them to make up the deficit in intake completely within 30 min. Distending the rumen by 800 ml had no effect on intake (P < 0.05). Distending the abomasum with up to 1000 ml water in a balloon depressed intake by 0.11 g/ml after 30 min of feeding with compensatory feeding being significant (P < 0.05) but incomplete.

4. Combinations of reticular distension up to 800 ml and of abomasal distension up to 1200 ml did not have additive depressing effects on intake.

1. Alkaline phosphatase (EC 3.1.3.1) from many rat tissues was separated into two or three bands by electrophoresis on polyacrylamide gel. Ten of the bands had different electrophoretic mobilities, but some were present in more than one tissue.

2. Bands from the corresponding tissues of magnesium-deficient and control rats were qualitatively similar, but there were quantitative differences in the distribution of enzyme activity between them.

3. Mg deficiency had differential effects on the absolute activity of individual bands, but two main types of response were observed. There was an increase in the activity of the first bands from liver and kidney, the second band from femur and both bands from spleen, whereas the first band from femur, the first and second bands from intestinal mucosa and the second bands of serum, liver and kidney all decreased in activity during the deficiency.

4. The change in total alkaline phosphatase activity of a tissue during Mg deficiency depended on the ratio between the enzyme components within it.

Adult male Japanese quail (Coturnix coturnix japonica) were starved for 48 or 60 h and then refed for either 24 or 48 h. Weight and lipid content of carcass and livers were determined, as was the lipid content of plasma. In addition, the activities of acetyl-CoA carboxylase (EC 6.4.1.2; CBX), fatty acid synthetase (FAS), ATP citrate lyase (EC 4.1.3.8; CCE) and malate dehydrogenase (decarboxylating) (NADP) (EC 1.1.1.40; ME) were assayed in liver and in abdominal and neck adipose tissues (AAT and NAT, respectively).

Body-weight and carcass lipids failed to return to normal in quail that had been starved for 48 h and refed during 24 h. When starving lasted 60 h, carcass lipids almost resumed the normal level only after 48 h of refeeding. All refeeding treatments caused a 2–3-fold increase in liver weight, with a parallel rise in fat content.

In the livers of the refed quail the specific activities of all enzymes, except CBX, reached or slightly exceeded pre-starvation levels. Because of liver enlargement, the total activities of the lipogenic enzymes in the starved–refed quail exceeded pre-starvation levels. In the normally-fed quail the contribution of AAT and NAT to total lipogenesis was insignificant, and in the starved–refed birds it still remained very small compared to that of liver, despite the pronounced relative increase of lipogenic enzyme activities in these adipose tissues.

1. The effects of supplementation of a cellulose-based diet with either urea, casein or formaldehydetreated (HCHO)-casein were studied in growing lambs. Responses were measured in terms of growth rate, food intake and food conversion ratio.

2. In Expt 1 lambs were given free access to a basal diet containing (g/kg) oat-hulls (700) and solka floc (300) (containing 5 g nitrogen/kg dry matter (DM)) supplemented (g/kg basal diet) with either urea (25), untreated casein (75), HCHO-casein (75) or combinations of these. Food intake was increased on average by 27% above that on the basal diet by the addition of either urea, casein, HCHO-casein plus urea. Urea plus HCHO-casein when given as a combined supplement further increased food intake on average by 60% above that on the basal diet. Supplements of either urea, casein, HCHO-casein or casein or casein plus urea changed a mean live-weight loss of 40 g/d on the basal diet to a mean live-weight gain of 56 g/d. Urea plus HCHO-casein further increased lamb growth to 112 g/d.

3. In Expt 2 lambs were given free access to the basal diet (plus 25 g urea/kg diet) used in Expt I. In this experiment the content of insoluble and soluble casein in the diets was varied by the addition of HCHO-casein and untreated casein of 0, 150; 50, 100; 100, 50 and 150, o g/kg basal diet respectively. Maximum lamb growth (141 g/d) was obtained with a supplement of 25 g urea plus 100 g HCHO-casein and 50 g casein/kg.

4. The growth responses to these supplements suggest a requirement for soluble N by the rumen microorganisms to maximize rumen fermentation, and for maximum growth rate on this diet a further requirement for amino acids produced by protein which has escaped degradation in the rumen.

5. Fermentation and the absorption of nutrients were examined in Expt 3 in lambs fitted with simple ‘T’-shaped cannula in the duodenum and ileum, and fed ad lib. one of the diets: a basal diet of oat hulls and solka floc, or the basal diet supplemented (g/kg) with either urea (25), urea plus casein (150), or urea (25) plus HCHO-casein (150). The rates of production of volatile fatty acids (VFA), methane and microbial cells were measured using isotope-dilution techniques. The apparent absorption of nutrients was determined by differences in the quantity of those nutrients in digesta at the duodenum and ileum.

6. Supplements of urea, urea plus casein and urea plus HCHO-casein increased organic matter (OM) intake in lambs by 65% above that on the basal diet. OM digestibility was unchanged by the from of nitrogen supplementation. The rates of production of all fermentation end-products varied directly with voluntary food intake.

7. Rumen methane production remained constant at 0.09 mol methane/MJ metabolizable energy (ME) intake on all diets, which represented an 11% loss of digestible energy (DE). Hindgut methane production was highest on the urea-supplemented diet.

8. The rate of VFA production (mol/MJ ME intake) in the rumen was highest on the diet supplemented with urea in comparison with the basal, urea plus casein and urea plus HCHO-casein diets (which were not significantly different). The molar proportions of the individual VFA in rumen fluid were not significantly different between diets except for the branched chain and higher fatty acids which were highest in proportion with the urea plus casein diet.

9. The loss of energy in the faeces, urine or as methane in expired air was not influenced by the form of N supplementation. DE and ME were greater on the supplemented diets, as a result of the increased OM intake of these diets.

10. There was no effect of the form of N supplementation on OM digested in the rumen, small intestine or large intestine. Of an increase in OM intake, apparently 55% was digested in the rumen (of which 19% was incorporated into rumen micro-organisms) and 26% disappeared in the small intestines. The apparent digestibility of OM for all diets was 0.67.

1. Balance studies were carried out with rats and golden hamsters (Mesocricetus auratus) given diets high and low in calcium (10.8 and 5.1–5.2 g Ca/kg respectively) and high and low in phytate (3.4 and 1.6 g phytate-phosphorus/kg respectively) in a 2 × 2 factorial experiment.

2. Values for Ca absorption and phytate availability (relative to the amount ingested) and for urinary excretion of Ca and P were significantly higher in the hamster than in the rat for all four diets.

3. Phytate availability was significantly greater on the low-Ca than on the high-Ca diets with both species.

4. Ca absorption was greater on the low-phytate than on the high-phytate diets but the differences were significant only for the hamster.

5. Absorption of both Ca and P was poorly controlled in the hamster compared to the rat.

1. Lambs with cannulas in the duodenum and ileum were allowed free access to one of four diets: a basal diet of oat hulls and solka floc, or the basal diet supplemented with either urea, urea plus casein or urea plus formaldehyde-treated (HCHO)-casein. Mean nitrogen intake was 1.9 g N/d for the basal diet and 15.0, 32.4 and 36.9 g N/d respectively for the other diets.

2. The rate of irreversible loss of ammonia from the rumen pool estimated using 15NH+4 was highest on the casein diet (33 g NH3-N/d) by comparison with 18 g NH3-N/d for the urea and HCHO-casein diets and 7 g NH3-N/d for the basal diet.

3. The proportions of bacterial and protozoal N in the rumen derived from rumen ammonia did not differ significantly between the supplemented diets and were 0.66 and 0.52 respectively.

4. Estimation of 15N flowing to the duodenum during continuous infusions of 15NH+4 into the rumen indicated considerable ammonia absorption from the rumen on all the diets. Greatest absorption of ammonia (21 g N/d) apparently occurred in animals on the diet supplemented with urea and casein.

5. The estimated microbial non-ammonia-N (NAN) flowing out of the rumen per unit organic matter fermented in the rumen (FOM) was similar on all diets, i.e. 21.3 (±1.09) g N/kg FOM. The requirement for dietary fermentable N for microbial N production on these diets was 1.2 (±0.07) g N/MJ ME.

6. The flow of NAN into the duodenum and throught the ileum, and total N in the faeces was significantly influenced by the form of N supplementation. The flow of NAN into the duodenum for the HCHO-casein diet (27 g N/d) was more than twice that for the other diets (11 g N/d). The flow of NAN through the ileum and excretion of total N in the faeces was also greater with the HCHO-casein diet than with all other diets. The apparent digestibility of NAN in the small intestine ranged between 0.62–0.66 for all diets.

7. Urea and casein supplements were apparently completely degraded in the rumen. In contrast, the HCHO-casein was almost completely resistant to degradation in the rumen and only 65% of the HCHO-casein was digested in the small intestine.

8. Protein absorbed: energy absorbed (expressed as NAN digested in the small intestine/MJ ME) was calculated to be 5.5 (±0.70) for the basal, urea and urea-plus-casein diets, and 11.6 (±1.71) for the urea-plus-HCHO-casein diet.