Energy and nutrient intakes were assessed in 136 children, aged 7–8 years and living in and around Edinburgh, using the 7 d weighed inventory technique. The results were compared with UK dietary reference values (DRV) for energy, macronutrients and micronutrients. NSP intakes were compared with a calculated reference value (CRV). Mean energy intakes were close to the estimated average requirement for both boys and girls. Mean percentages of food energy derived from fat and saturated fat were high in relation to DRV (37 and 14 compared with 35 and 11 respectively). Mean percentage of food energy derived from total carbohydrate was close to the DRV of 50 but intakes of starch appeared to be low and intakes of total sugars high (23 and 26% food energy respectively). Superficially, this suggests that there is a need to alter the balance of carbohydrate in favour of increasing starch and lowering total sugar. There was, however, a clear ‘fat-sugar seesaw’, i.e. children with a high percentage energy from total sugars had a low percentage energy from fat, and vice versa. In view of this finding, it is possible that efforts to reduce total sugar intake in children may result in a further increase in percentage energy from fat. Mean intakes of NSP were only 50% of the CRV, but this guideline may be set too high. Mean intakes of most micronutrients were above reference nutrient intakes. Reported low intakes of Zn and Se were treated with caution due to the perceived incompleteness of the data for these in the nutrient database. The authors concluded that targeting high intakes of total fat and saturated fat should be the health priorities in this age-group.

Current recommendations for energy requirements in the elderly are based on assumed levels of physical activity relative to BMR (1.5 x BMR). The main aim of the present study was to establish whether these recommendations might be applicable to a randomly-selected group of free-living elderly men (all over 75 years of age). BMR was measured by indirect calorimetry and total energy expenditure (TEE) by the doubly-labelled-water technique. Further aims included evaluating the applicability of a variety of BMR prediction equations and whether assessed quality of life reflected any measured indices of energy expenditure. The mean value for daily energy requirement was found to be 1.5 x BMR (89 J/kg per min) but with substantial inter-individual variation (SD 0-2 x BMR; 14 J/kg per min). The bias between measured TEE and TEE estimated (1.5 x BMR) from the various BMR predictions varied according to which equation was used (-10-+ 8% of the mean) with substantial 95 YO limits of agreement (28-30%of the mean). TEE and physical activity plus thermogenesis (TEE -BMR) were positively related to activities of daily living, but no relationships were apparent between these and perceived quality of life. It is concluded that, despite considerable inter-individual variability, national recommendations for energy requirements of elderly people are applicable to this randomly-selected group of free-living men over 75 years of age but that substantial variation exists when attempts are made to estimate TEE from measurements or predictions of BMR.

An experiment was conducted in the pig to determine the consequences of deprivation of exocrine pancreatic secretion on the composition and quantity of nutrients absorbed after intake of a balanced diet. Five growing pigs (53·8 kg body weight) were fitted with permanent catheters in the portal vein and the carotid artery and with an electromagnetic flow probe around the portal vein to measure the exchanges between the blood and the intestinal lumen. They were also fitted with a permanent catheter in the duct of Wirsung to educe the exocrine pancreatic secretion and another one in the duodenum in order to reintroduce it. In each animal, glucose, amino-N and amino acid absorption as well as insulin and glucagon production were measured over a period of 10 h after the meal (semi-purified diet based on purified starch and containing 180 g fish meal/kg, DM content of the meal 731 g), either in the presence of pancreatic juice (group C : immediate reintroduction), or in the absence of pancreatic juice (group D: deprivation). The deprivation of pancreatic juice provoked a marked depression in the absorption of glucose (D 67·9 (SEM 27·9) g/10 h, C 437·7 (SEM 39·5) g/10 h, P < 0·00l), and of amino-N (D 7·55 (SEM 0·54) g/10 h, C 15·80 (SEM 0·79) g/10 h, P < 0·001). The composition of the mixture of amino acids in the portal blood was only slightly modified: only the levels of histidine (P < 0·05) and of valine (P < 0·06, NS) decreased in the absence of pancreatic juice. Insulin production was much lower (by 64%, P < 0·05) in the absence of pancreatic juice whereas that of glucagon was not affected.

The present study was performed in order to investigate the effect of chronic heat exposure (32",constant) on growth, body composition and energy retention of broiler chickens in relation to age. At 2and 4 weeks of age, fifty-four male Shaver broiler chickens were allocated to three treatments accordingto the following design: 22", ad lib. feeding (22AL); 32", ad lib. feeding (32AL); and 22", pair-feeding with the 32" group (22PF). Ambient temperature was kept constant at either 22 or 32" for 2 weeks. Heatexposure decreased feed intake by 14% YO between 2 and 4 weeks and by 24% YO between 4 and 6 weeks of age. Even with the same feed intake, chicks gained less weight at 32" than at 22", 55% less in young chickens and 22% less in older ones. Hot environmental conditions thus resulted in decreased feed efficiency; the feed:gain ratio was 2·85 at 32" compared with 2·06 at 22" in 22AL birds for the period4—6 weeks. Body composition appeared significantly affected by high ambient temperature. Feathering was reduced at 32" in absolute weight but not as a proportion of body weight. Heat-exposed birds showed a decrease in body protein content, protein gain and protein retention. Group 32AL birds were fatter than the pair-fed (22PF) or ad fib.-fed (22AL) groups at 22". The percentage of energy retained as fat was 79 in heat-exposed chickens compared with 64 in the control groups. The energy retained as protein:energy retained as fat for groups maintained at 22" (0·56) was twice that forthose maintained at 32" (0·28). These modifications should be investigated further in relation to metabolic and endocrinological changes.

The response in whole-body and splanchnic tissue mass and isotope amino acid transfers in both plasma and blood has been studied in sheep offered 800 g lucerne (Medicago sutiva) pellets/d. Amino acid mass transfers were quantified over a 4 h period,by arterio-venous procedures, across the portal-drained viscera (PDV) and liver on day 5 of an intravenous infusion of either vehicle or the methylated products, choline (0.5 g/d) plus creatine (10 g/d). Isotopic movements were monitored over the same period during a 10 h infusion of a mixture of U-13C-labelled amino acids obtained from hydrolysis of labelled algal cells. Sixteen amino acids were monitored by gas chromatography-mass spectrometry, with thirteen of these analysed within a single chromatographic analysis. Except for methionine, which is discussed in a previous paper, no significant effects of choline plus creatine infusion were observed on any of the variables reported. Whole-body protein irreversible-loss rates ranged from 158 to 245 g/d for the essential amino acids, based on the relative enrichments (dilution of the U-13C molecules by those unlabelled) of free amino acids in arterial plasma, and 206-519 g/d, when blood free amino acid relative enrichments were used for the calculations. Closer agreement was obtained between lysine, threonine, phenylalanine and the branched-chain amino acids. Plasma relative enrichments always exceeded those in blood (P < 0.001), possibly due to hydrolysis of peptides or degradation of protein within the erythrocyte or slow equilibration between plasma and the erythrocyte. Net absorbed amino acids across the PDV were carried predominantly in the plasma. Little evidence was obtained of any major and general involvement of the erythrocytes in the transport of free amino acids from the liver. Net isotope movements also supported these findings. Estimates of protein synthesis rates across the PDV tissues from [U-13C] leucine kinetics showed good agreement with previous values obtained with single-labelled leucine. Variable rates were obtained between the essential amino acids, probably due to different intracellular dilutions. Isotope dilution across the liver was small and could be attributed predominantly to uni-directional transfer from extracellular sources into the hepatocytes and this probably dominates the turnover of the intracellular hepatic amino acid pools.

The relationship between essential fatty acids (EFA) deficiency and the utilization of dietary protein, growth rate and survival of offspring was investigated in rats during development and reproduction. EFA deficiency was induced by feeding a 200 g casein/kg-based diet containing 70 g hydrogenated coconut oil (HCO)/lkg as the only source of fat. The conversion efficiency of dietary protein was assessed as net protein utilization (NPU), using a 10 d comparative carcass technique. Consumption of the deficient diet during the 10 d assay period induced biochemical changes characteristic of mild EFA deficiency in humans (triene:tetraene 0·27 (SD 0·04) compared with 0·026 (SD 0·004) for wn-deficient controls), but there were no significant changes in growth rate or protein utilization. These variables were also unchanged when the deficient diet was fed for an additional 7 d before the assay, although triene: tetraene increased to 0.8 (SD 0·02). Feeding the deficient diet for 63 d before assay produced severe EFA deficiency (triene:tetraene 1.4 (SD 0·3) v. 0·036 (SD 0·005) for controls), a fall in growth rate (25% during assay period), and NPU (31.5 (SD 0·63) v. 39.0 (SD 0·93) for controls). These severely-EFA-deficient animals had a 30% higher fasting-resting rate of energy metabolism than that of age-matched controls. However, there was no change in the rate of endogenous N loss. Voluntary energy consumption was increased in animals fed on deficient diets, either with 200 g protein/kg, or protein free. The reduced efficiency of protein utilization could be entirely accounted for by the restricted amount of energy available for growth and protein deposition. Consumption of an EFA-deficient diet during pregnancy and lactation resulted in high mortality (11% survival rate at weaning compared with 79% for controls) and retarded growth in the preweaning offspring. It is concluded that animals are particularly sensitive to EFA deficiency during reproduction and pre- and post-natal stages of development. However, after weaning only severe EFA deficiency retarded growth, primarily through changes in energy balance.

The present study examines the suggestion that in the absence of adequate bile and pancreatic juice, which support the absorption from the gut of long-chain fatty acidsinto lymph, the fatty acids are absorbed directly into the portal blood. Oleic acid (18:l) partitioning between lymph and portal blood was investigated in intact and bile- and pancreatic juice-diverted rats. In a first set of experiments, 18: 1 absorption from the gut into lymph and blood was studied by continuous recovery of the mesenteric lymph for 6 h and mesenteric portal venous blood for 1 h. In a second set of experiments, esterification processes were investigated by study of the mucosal distribution of labelled lipids and by mono- and diacylglycerol acyltransferase (EC 2.3.1.22 and EC 2.3.1.20 respectively) specific activities. In the bile- and pancreatic juice-diverted rats the absorption of labelled 18:l into lymph was significantly reduced during the first 3 h of intraluminal infusion of this substrate. In such rats a compensatory absorption of labelled 18: 1 into mesenteric portal blood was not observed. At 6 h after micellar lipid- mixture infusion, the overload of lipids both in free form and as triacylglycerols persisting in the mucosa paralleled the lower acyltransferase specific activities observed in bile- and pancreatic juice-diverted rats. These studies demonstrate the absence of a previously proposed compensatory absorption of 18: 1 into portal blood when absorption into lymph is impaired by an inadequate supply of bile and pancreatic juice.

The in vitro degradation of dietary fibre from three brown seaweeds (Himanthalia elongata, Laminaria digitata and Undaria pinnatiJda) was studied, using human faecal flora. Two sets of fibre were tested: (1) total algal fibres extracted from the whole algae, mainly composed of alginates, and (2) purified fibres (sulphated fucans, Na-alginates and laminarans) representative of those contained in the whole brown algae. Mannuronate, one algal component, was also investigated. Substrate disappearance and short- chain fatty acid (SCFA) production were monitored after 6, 12 and 24 h fermentation. Gas production was followed hourly during the first 9 h and then at 12 and 24 h. Sugarbeet fibre was used as a fermentation reference substrate. According to the fermentative indices used, most of each of the total algal fibres disappeared after 24 h (range 60–76 %) hut, unlike the reference substrate, they were not completely metabolized to SCFA (range 47–62 %). Among the purified algal fibres, disappearance of laminarans was approximately 90% and metabolism to SCFA was approximately 85% in close agreement with the fermentation pattern of reference fibres. Sulphated fucans were not degraded. Na- alginates exhibited a fermentation pattern quite similar to those of the whole algal fibres with a more pronounced discrepancy between disappearance and production of SCFA: disappearance was approximately 83 % but metabolism was only approximately 57 YO. Mannuronate was slowly fermented hut its metabolism corresponded to its disappearance from the fermentative medium. Thus, the characteristic fermentation pattern of the total fibres from the three brown algae investigated was attributed to the peculiar fermentation of alginates, and mannuronate was shown not to be directly involved.

Fractional apparent absorption of Zn and Ca from a wheat-milk-based infant cereal was studied in six healthy infants (18-30 weeks old). Mineral absorption was measured by a stable-isotope technique based on faecal excretion of the isotopes. Each test meal (40 g cereal) was extrinsically labelled with 70Zn and 42Ca before intake. All faecal material passed during the 21 d following intake of the labelled test meal was collected on trace-element-free nappies. Individual stool samples were analysed for their content of ‘OZn and 42Ca by thermal ionization mass spectrometry. Apparent absorption was calculated as intake minus total faecal excretion of the isotopes over 68-92 h after administration. The fractional apparent absorption values for Zn and Ca were 33.9 (SD 164) % (range 19.2-639 %) and 53.5 (SD 12.6) %) (range 36.7-71.7 %) respectively. Re-excretion of absorbed 70Zn (> 68-92 h to 21 d after intake of the labelled meal) was 044 (SD 038) %] of administered dose while only one infant re-excreted detectable amounts of 42Ca (1.74%) of administered dose). The analysis of individual stool samples confirmed that 72 h is a sufficient time period for complete collections of non-absorbed isotopes in faecal material from infants during the weaning period and that re-excretion of initially absorbed 70Zn and 42Ca (> 68-92 h to 21 d after intake of the labelled meal) is negligible.

The effect of fermentation on colonic absorption of Ca and Mg was investigated in 8-week-old rats adapted to diets containing either digestible wheat starch (DS diets) or including resistant starch, i.e. 350 g raw potato starch/kg (RS diets). The dietary Ca level of the DS and RS diets was 2·5 or 7·5 g/kg. RS diets resulted in enlargements of the caecum together with hypertrophy of the caecal wall. Acidification of the caecal contents by mictobial fermentation of RS was influenced by the dietary Ca level. Very acidic pH conditions and relatively low concentrations of short-chain fatty acids, in the presence of lactic acid fermentation, were observed with the 2·5 g Ca/kg level. Rats fed on RS diets had a bhigher pencentage of soluble Ca (and inorganic phosphate) in the caecum, particularly of rats adapted to the high Ca level. As a result of the hypertrophy of the caecal wall and of an elevated concentration of soluble Cas, the caecal absorption of Ca was 5-6 fold higher in the RS groups than in the DS groups. The difference between dietary intakle and faecal excretion (DI-FE) of Ca was higher in rats fed on RS diets than in those fed on DS diets, when the dietary Ca level was 2·5 g/kg. With the higher Ca intake the elevated rate of Ca absorption from the caecum in RS-fed rats was not paralleled by an enhanced DI-EE difference: this suggests a shift of the Ca absorption towards the large intestine. Feeding Rs diets also enhanced Mg caecal absorption, resulting in the substatntially higher DI-FE difference for Mg, especially with the 2·5 g Ca/kg diets, because a high Ca intake tends to inhibit Mg absorption. The present findings support the view that the large intestine may represent a major site of Ca (and Mg) absorption when acidic fermentations take place. This process could improve the digestive Ca balance when the dietary Ca supply is low; when the Ca supply is affluent, it rather shits Ca absorption towards a more distal site fo the digestive tract.