1. Using a double-lumen tube perfusion system, solutions of lactose (50, 125 and 250 mmol/l) were introduced into the upper jejunum of six Zambian African subjects. By reference to a non-absorbable marker, polyethylene glycol, mol. wt 4000, the rates of absorption of lactose from each solution were calculated for a 300 mm jejunal segment.

2. In three subjects total lactase activity of the jejunal mucosa and brush-border lactase and other disaccharidase activities were estimated. The jejunal total and brush-border lactase activities were low. Jejunal morphology was normal for African subjects.

3. All subjects suffered abdominal colic and diarrhoea during and after the lactose perfusions. The kinetic curves for lactose were very shallow, and with all perfused solutions, there was a net movement of water into the jejunal lumen. The limited number of subjects, and the low and narrow range of enzyme activity, did not permit correlation between lactose absorption rate and lactase activity.

4. In Zambian African subjects with adult hypolactasia, the jejunal mucosa absorbs a very small proportion of the perfused lactose.

The present study was designed to examine the effect of cellulose (CL) on postprandial glycaemia and insulinaemia when ingested with glucose (G), casein (CS) and maize oil (CO) in various combinations. The study was conducted on five healthy male volunteers, on each of whom five meal tolerance tests were performed. The meals were isoenergetic and consisted of G; G and CL; G, CS and CL; G, CO and CL; G, CS, CO and CL. The meals were administered after an overnight fast. In addition to a fasting venous blood sample, blood was collected 0.5, 1.0, 1.5 and 2.0 h after ingestion for measurement of serum glucose and insulin levels. The glycaemic response to G+CS+CL and G+CS+CO+CL was significantly lower, while the insulinaemic response to G+CL was significantly higher than that to G. Addition of CL to G did not alter the glycaemic response, but accentuated the insulinaemic response. Further addition of CS in isoenergetic meals attenuated the glycaemic response, which may be because of a reduction in the amount of G in the meals. Like CS, CL also seemed to have an insulinotropic effect. The mechanism of the insulinotropic effect of CL cannot be deduced from the present study, but it is possible that like G, CL also stimulates gastric inhibitory peptide (GIP) secretion from the duodenum, which in turn stimulates insulin secretion.

Studies were carried out on conscious female non-pregnant (NP) and pregnant (P; third-trimester) dogs (n 16; eight animals per group) to define the role of the liver in mixed meal disposition with arteriovenous difference and tracer techniques. Hepatic and hindlimb substrate disposal was assessed for 390 min during and after an intragastric mixed meal infusion labelled with [14C]glucose. The P dogs exhibited postprandial hyperglycaemia compared with NP dogs (area under the curve (AUC; change from basal over 390 min) of arterial plasma glucose: 86 680 (sem 12 140) and 187 990 (sem 33 990) mg/l in NP and P dogs, respectively; P < 0·05). Plasma insulin concentrations did not differ significantly between the groups (AUC: 88 230 (sem 16 314) and 69 750 (sem 19 512) pmol/l in NP and P dogs, respectively). Net hepatic glucose uptake totalled 3691 (sem 508) v. 5081 (sem 1145) mg/100 g liver in NP and P dogs, respectively (P = 0·38). The AUC of glucose oxidation by the gut and hindlimb were not different in NP and P dogs, but hepatic glucose oxidation (84 (sem 13) v. 206 (sem 30) mg/100 g liver) and glycogen synthesis (0·4 (sem 0·5) v. 26 (sem 0·7) g/100 g liver) were greater in P dogs (P < 0·05). The proportion of hepatic glycogen deposited via the direct pathway did not differ between the groups. Hindlimb glucose uptake and skeletal muscle glycogen synthesis was similar between the groups, although final glycogen concentrations were higher in NP dogs (9·6 (sem 0·6) v. 70 (sem 0·6) mg/g muscle; P < 0·05). Thus, hepatic glucose oxidation and glycogen storage were augmented in late pregnancy. Enhanced hepatic glycogen storage following a meal probably facilitates the maintenance of an adequate glucose supply to maternal and fetal tissues during the post-absorptive period.

Simulation models of nutrient utilisation ignore that variation in pig system components can influence the predicted mean and variance of the performance of a group of pigs. The objective of this study was to develop a methodology to investigate how variation in feed composition would (a) affect the outputs of a nutrient utilisation model and (b) interact with variation that arises from the traits of individual pigs. We used a P intake and utilisation model to address these characteristics. Introduction of stochasticity gave rise to a number of methodological challenges – for example, how to generate variation in both feed composition and pigs and account for correlations between ingredients when modelling variation associated with feed mixing efficiency. Introducing variation in feed composition and pig phenotype resulted in moderate decreases in mean digested, retained and excreted P predicted for a population of pigs and an increase in their associated CV. A lower percentage of pigs in the population were predicted to meet their requirements during the feeding period considered, by comparison with the no-variation scenario. Variation in feed ingredient composition contributed more to performance variation than variation due to mixing efficiency. When variations in both feed composition and pig traits were considered, it was the former rather than the latter that had the dominant influence on variability in pig performance. The developed framework emphasises the consequences of random variability on the predictions of nutrient utilisation models. Such consequences will have a significant impact on decisions about management strategies such as feeding that are subject to variation.

1. The confounding effects of undernourishment and body cooling, resulting from maternal separation, were investigated by separating food and warmth deprivation. Rat pups aged 3–16 d were deprived of food for alternate 24-h periods by removal from the lactating mother. Some of the pups were placed with a foster mother, who kept them warm, whereas others were put in an empty cage at 22° which resulted in a sharp drop in body temperature.

2. Pups which were kept warm showed great fluctuations in weight between periods of starvation and feeding. The cooled pups lost less weight during deprivation but also recovered less on refeeding.

3. The resultant growth rate was much lower in non-fostered (i.e. cooled) than in fostered pups.

4. Up to the age of 8 d, cooled pups failed to raise their body temperature above that of the surroundings and did not digest the milk in their stomachs. Although, thereafter, they were able to raise their temperature to 26° and to digest stomach contents, the extra energy expended resulted in more severe growth restriction.

5. One-third of the pups died at 16 d but the rest were quickly rehabilitated by ad lib. feeding and showed a normal growth rate, although they remained smaller than the controls.

6. The development of nipples, hair, eye opening and vaginal opening was related more to chronological age than to weight.

7. A side effect of cooling was an almost complete abolition of active (REM) sleep, which is normally very high in infants; a slight rebound increase in active sleep was seen at 21 d. Direct as well as side effects of cooling may thus be responsible for some of the observed consequences of maternal separation.

1. Guinea-pigs were growth-retarded in early life by feeding their mothers a restricted quantity of food during the second half of pregnancy. After birth, all animals were fed ad lib. Body-weights were recorded weekly and behavioural tests were made on adult males. The animals were then killed and their brains dissected into forebrain, cerebellum and brain stem. These regions were weighed and DNA-phorphorus content measured.

2. At 14 weeks each male was paired with another male for 10 min on four consecutive days and their social behaviour scored. Tests 1 and 2 were on like-treatment pairs and tests 3 and 4 on unlike-treatment pairs. At 25 weeks the same animals were subjected to six graded series of brief, unavoidable shocks and their responses recorded. After 3 d, thresholds of aversion to electric shock were measured by recording the period of time spent on the ‘safe’ side of a rectangular box at five shock levels.

3. Undernourished guinea-pigs were significantly lighter than controls at birth but not at adulthood. Regional brain weights and DNA-P content of previously-undernourished guinea-pigs were significantly lower than those of controls, with the greatest deficit in brain stem.

4. Pairs of previously-undernourished guinea-pigs began to interact more quickly and threatened and nosed each other more often than pairs of controls. In mixed pairs previously-undernourished animals chased controls more than their control partners chased them. There were no differences between groups in responsiveness to unavoidable shock or in aversion thresholds.

Zafeiridis et al.1 recently described the effects of resistance exercise on postprandial TAG concentrations. Zafeiridis and colleagues observed a reduction in 6 h total and incremental TAG area under the curve concentrations after resistance exercise protocols expending approximately 0·76 and 1·40 MJ.

Extracts of mulberry have been shown to reduce post-prandial glucose (PPG) and insulin (PPI) responses, but reliability of these effects and required doses and specifications are unclear. We previously found that 1·5 g of a specified mulberry fruit extract (MFE) significantly reduced PPG and PPI responses to 50 g carbohydrate as rice porridge, with no indications of intolerance. The trials reported here aimed to replicate that work and assess the efficacy of lower MFE doses, using boiled rice as the carbohydrate source. Two separate randomised controlled intervention studies were carried out with healthy Indian males and females aged 20–50 years (n 84 per trial), with PPG area under the curve over 2 h as the primary outcome. Trial 1 used doses of 0, 0·37, 0·75, 1·12 and 1·5 g MFE in boiled rice and 0 or 1·5 g MFE in rice porridge. Trial 2 used doses of 0, 0·04, 0·12, 0·37 g MFE in boiled rice. In trial 1, relative to control, all MFE doses significantly decreased PPG (–27·2 to −22·9 %; all P ≤ 0·02) and PPI (–34·6 to −14·0 %, all P < 0·01). Breath hydrogen was significantly increased only at 1·5 g MFE (in rice porridge), and self-reported gastrointestinal symptoms were uniformly low. In trial 2, only 0·37 g MFE significantly affected PPG (–20·4 %, P = 0·002) and PPI (–17·0 %, P < 0·001). Together, these trials show that MFE in doses as low as 0·37 g can reliably reduce PPG and PPI responses to a carbohydrate-rich meal, with no apparent adverse effects.

The knowledge base underpinning the setting of nutrient requirements for children and adolescents is not very secure. The advent of the concepts of optimal nutrition and functional foods has encouraged the possible use of functional effects as criteria for adequate nutrition in this age group. Target functions have been identified for growth development and differentiation and for behavioural and cognitive development. However, ideal markers or effects for these are not generally available. Additionally, nutrition in young people should avoid predisposing them to diet-related disease in later life. It is suggested that functional effects should include markers of reduction of risks of disease (nutritional safety) as well of benefits for health and well-being. Such markers of functional effects should be expected to arise from fundamental studies of nutrient–gene interactions and post-genomic metabolism.

1. Weanling rats, aged 21 d, given a 40 g casein/kg diet for 25 d were compared with ‘age-matched’ controls given a 200 g casein/kg diet and with ‘weight-matched’ weanling controls.

2. The protein-malnourished rats demonstrated failure of weight gain and linear growth, hypoproteinaemia, hypoalbuminaemia and fatty liver.

3. Autoradiography of the tibia was carried out 24 h after intraperitoneal injection of Na235SO4 (0.1, 1.0, 2.0, 5, 10 μCi/g body-weight). Sections of tibia, humerus and costochondral junction were stained by haematoxylin and eosin, resorcin-crystal violet and picro-fuchsin, Alcian Blue at pH 0.1 and pH 2.5, Alcian Blue at pH 5.7 with magnesium chloride (0.1, 0.7, 1.0 m), and by Alcian Blue after ovine testicular hyaluronidase (EC 3.2.1.35) digestion. The width of the upper tibial epiphysis was measured and the histological and histochemical features of the epiphyses studied.

4. The incorporation of 35SO4 into the epiphyses of the protein-malnourished animals was markedly reduced. The chondrocytes were small and flattened with frequent pyknotic nuclei. The staining characteristics of the cartilagenous matrix was qualitatively similar in all animals. The epiphyses in malnutrition were found to be thin, all zones being affected. The upper tibial epiphyses (mean±sd; μm) were 202 ±46 for the protein-malnourished animals, 367±52 for age-matched controls and 578±40 for weight-matched controls.

5. The changes found resemble those after hypophysectomy and the possible hormonal factors are discussed.

In pets, as in humans, there is increasing interest in interventions that promote ‘health and well-being’ into later life and extend these beyond their current limits. The purpose of this review was to assess the relevance of current knowledge of ageing in humans, described in a companion paper, as well as reviewing recent research on ageing in pet populations. The role of diet and other factors that influence the ageing process and ultimately lifespan in pets are highlighted in this review; in addition, future opportunities and challenges to further our understanding of the ageing process in pets are identified. Advancing knowledge of the fundamental biology of ageing will be key for the development and evaluation of strategies that extend both the quality and the quantity of lifespan in human and pet populations.

The objective was to study the evaluation of serum transferrin receptor (sTfR) for Fe deficiency in women of child-bearing age. Primary screening was performed in 942 women ranging in child-bearing age. Serum ferritin (SF), Zn protoporphyrin (ZPP) and Hb were determined. Then the subjects were divided into four groups: normal, Fe store depletion (IDs), Fe-deficiency erythropoiesis and Fe-deficiency anaemia. sTfR was determined and sTfR/SF (sTfR/logSF and log(sTfR/SF)) was calculated. Changes of sTfR in women of different Fe status were observed. A receiver-operating characteristic (ROC) curve was used to evaluate whether sTfR had proper diagnostic efficacy for functional Fe deficiency. The levels of sTfR increased significantly along with the aggravation of Fe deficiency. Increase of STfR/SF along with the aggravation of Fe deficiency was more significant than that of sTfR. STfR had a significant negative correlation with SF and Hb, while it had a significant positive correlation with ZPP. The ROC curve showed that the diagnostic effective rate of sTfR for Fe deficiency could reach 83 %. At this point, the sensitivity was 79 % and the specificity was 63 %. Log(sTfR/SF) could be considered to have the highest effective ratio in detecting IDs, since it reached 99 %. STfR and sTfR/SF could both reflect body Fe-deficiency status specifically. They could be used as reliable indicators for evaluating Fe status and diagnosing Fe deficiency in women of child-bearing age.

This paper looks back on the setting and messages of the review ‘Selenium in Global Food Systems’(1) (see Abstract, Fig. 1) and highlights related findings over the 20 years since its publication. Key papers are cited.

The effect of body fat content on the protein metabolism of energy-restricted sheep has been studied in two experiments. In the first experiment, six Suffolk-cross wether sheep, three weighing about 39 kg and three of about 61 kg, were given progressively increasing amounts of casein-N from 0 to 3000 mg N/kg metabolic body weight (W0·75) daily with constant energy, 91 kJ/kg W0·75 daily, from a high-propionic acid mixture of volatile fatty acids (VFA). In the second experiment, two lean and two fat sheep of similar body weights were given progressively increasing amounts of casein with the same VFA mixture. All the animals attained a positive N balance when they were in negative energy balance. N balance was not affected by body fatness of the magnitude studied, although lean animals utilized increasing levels of standard VFA (acetate-propionate-butyrate 65:25:10, molar proportions) infusion for N accretion more efficiently than fat animals. Endogenous energy was utilized for protein accretion with an efficiency of 0·56. Supply of glucogenic VFA equivalent to 28 mmol glucose/kg W0·75 reduced fasting N excretion by 39%. Fasting heat production decreased from 335 to 300 kJ/kg W0·75 with the infusion of casein and glucogenic VFA. It is argued that fasting induces additional heat losses due to raised protein metabolism and is unsuited as a baseline for dietary assessment.