bluuebunny/crossref_metadata_2025 huggingface dataset:
A metabolic nitrogen balance study for 40 d and evaluation of the menstrual cycle on protein requirement in young Nigerian women
Authors: Egun Gloria N. , Atinmo Tola
Published: June 2005

A long-term N balance study was carried out to determine the adequacy of an estimated protein requirement level recommended for young healthy Nigerian women and the effect of the menstrual cycle on the requirement. Eleven healthy young women, 25 (SD 2·6) years, were fed on a diet providing 0·6 g protein (N × 6.25)/kg per d and an average energy intake of 0·17 (SD 0·012) MJ/kg per d. Urine, faeces, sweat and menstrual fluids were collected for estimation of N balance. Menstrual N loss varied among individuals ranging from 46 to 124 mg N/d with an average of 89 (SD 21.8) mg N/d. Individual N balance was found to vary according to the day of the menstrual cycle. Positive N balances were recorded at about ovulation while negative balances were observed just before the onset of menstruation. The average N balance ranged from + 8·49 (SD 5·64) to − 430 (SD 7·84) mg N/kg per d. Nevertheless, an overall cumulative positive N balance of + 5·7 (SD 6·98) mg N/kg per d which did not change significantly with time was observed for the last 5 d of two consecutive 20 d diet periods, although three subjects were in negative N balance. Blood biochemical measurements were stable except for one subject who had elevated serum aspartate aminotransferase (EC 2.6.1.1) levels. These findings suggest that our estimate of protein requirements was sufficient to achieve N balance equilibrium in a majority (70 %) of young women. However, to satisfy 97·5 % of the population, slight adjustments might be necessary in the energy intake since subjects who were in cumulative negative N balance also lost weight.
Effect of iron deficiency on the digestive utilization of iron, phosphorus, calcium and magnesium in rats
Authors: Pallarés I. , Lisbona F. , Aliaga I. Lopez , Barrionuevo M. , Alférez M. J. M. , Campos M. S.
Published: June 2005

The influence of the source of dietary Fe (ferric citrate alone or mixed with bovine blood at a proportion of 1:1) (v/v) on the digestive utilization of Fe, P, Ca and Mg, and on haemoglobin regeneration efficiency (HRE) was investigated in control and Fe-deficient rats. Diet A contained (by analysis) 43·5 mg Fe/kg diet (as ferric citrate), and diet B contained 44·3 mg Fe/kg diet (ferric citrate—bovine blood). In Fedeficient rats fed on diet A or B the apparent digestibility coefficient (ADC) of Fe increased by 42·3 and 45·7% respectively. The ADC of Ca and Mg decreased significantly in Fe-deficient rats regardless of the source of dietary Fe. The HRE increased by 72·9% in Fe-deficient rats fed on diet A, and by 91·1% in Fe-deficient animals fed on diet B. In Fe-deficient rats fed on Fe for 10 d the values of haematological variables approached normality. However, serum Fe remained low, indicating that Fe reserves were still depleted. A deficient dietary supply of Fe for 30 d did not significantly modify the numbers of circulating leucocytes.
Utilization of ileal digestible amino acids by growing pigs: methionine
Authors: Batterham E. S. , Andersen L. M. , Baigent D. R.
Published: June 2005

An experiment was conducted to determine the utilization of ileal digestible methionine by growing pigs. Three methionine-deficient diets (0·09 g ileal digestible methionine/MJ digestible energy (DE)) were formulated using cottonseed meal, meat-and-bone meal and soya-bean meal respectively as the only source of methionine in the diet. An additional three diets were formulated with supplements of methionine to confirm that methionine was limiting in the first three diets. The growth performance and retention of methionine by pigs given the six diets over the 20–45 kg growth phase was then determined. Growth rates (g/d) of pigs given the three diets formulated to 0·09 g ileal digestible methionine/MJ DE were significantly different (P < 0·01): cottonseed meal 411, meat-and-bone meal 442, soya-bean meal 496 (SED 24·6). The response of pigs to the addition of methionine confirmed that methionine was limiting in these diets. Crude protein (N × 6·25) deposited by the pigs (g/d) was significantly higher (P < 0·05) for those given soya-bean meat (61) and meat-and-bone meal (57) relative io cottonseed meal (47; SED 3·3). The proportion of ileal digestible methionine retained by pigs given the three protein concentrates was: cottonseed meal 0·39, meat-and-bone meal 0·45, soya-bean meal 0·47 (SED 0·019). These results indicate that values for the ileal digestibility of methionine in protein concentrates do not reflect the proportion of methionine that can be utilized by the pig. It appears that, with heat-processed meals, a considerable proportion of the methionine is absorbed in a form(s) that is (are) inefficiently utilized.
Prevalence and type of anaemia in female cotton mill workers in Beijing, China
Authors: Li Ruowei , Chen Xue-Cun , Yan Huai-Cheng , Deurenberg Paul , Garby Lars , Hautvast Joseph G. A. I.
Published: June 2005

The present study investigates the prevalence and type of anaemia in Chinese female cotton mill workers. The prevalence of anaemia is reported in 447 non-pregnant female workers aged between 19 and 45 years. The mean value for haemoglobin (Hb) was 123 (SD 15) g/l and 150 of the total 447 subjects had Hb values below 120 g/l; thus 34% of the population was anaemic according to World Health Organization (WHO, 1975) criteria. The mean value for free erythrocyte protoporphyrin (FEP) was 419 (SD 215) μg/l; 55% of the total population had FEP values higher than 350 μg/l and 72% among the anaemic subjects. Serum ferritin (SF) was tested in all the women with a Hb value less than 120 g/l and 71 % of them had SF values below 12·0 μg/ls. Eighty women diagnosed as either Fe deficient or with Fe-deficient anaemia were selected for a diagnostic supplementation trial. They were randomly assigned to FeSO4(60 or 120 mg Fe/d) or placebo treatment for 12 weeks. Fe supplementation increased mean Hb values from 114 to 127 g/l (P< 0·001) and SF levels from 9·7 to 30·0 μg/l (P< 0·001), and decreased mean FEP values from 570 to 277 μg/l (P< 0·001). The response rate of Hb in the whole Fe-treated group or Fe-treated subjects with an Hb level less than 120 g/1 was 90 % or 92 % respectively. These findings indicate that the type of anaemia in this population was mainly Fe deficiency. It was also found that in this population the severity of anaemia, not the prevalence, was significantly related to the use of intra-uterine devices (IUD).
Maternal protein reserves and their influence on lactational performance in rats
Authors: Pine A. P. , Jessop N. S. , Oldham J. D.
Published: June 2005

To determine the contribution of tissue protein reserves to lactational performance, multiparous female Sprague-Dawley rats were mated, caged individually and offered a diet high in protein (215 g crude protein (N × 6·25; CP)/kg dry matter (DM);H) ad lib. until day 12 of gestation. Subsequently half the rats continued to receive diet H while the remainder were offered a diet low in protein (65 g CP/kg DM;L) until parturition. This treatment aimed to produce a difference in carcass protein at parturition. On day 1 of lactation females were allocated to either diet H or a low-protein diet (90 g CP/kg DM; L2) offered until day 13 of lactation, giving four lactation treatment groups HH, HL2, LH and LL2. Groups of females were slaughtered on days 2 and 12 of gestation and days 1 and 13 of lactation and carcass and major organs were analysed. Weight gain of standardized litters was used as an indicator of lactational performance. Maternal carcass protein contents at parturition were 43·5 (SE 1·2) and 38·7 (SE 0·8) g (P < 0·01) for diets H and L respectively. During lactation there was little change in carcass protein content of HH rats while LH rats appeared to replenish their depleted reserves. Food intake or lactational performance did not differ between these two groups. HL2 and LL2 rats lost carcass protein with HL2 rats losing more than LL2 rats (P < 0·05). Intake and lactational performance were reduced compared with that on diet H (P < 0.05) but for the first 6 d of lactation were both greater (P < 0·05) for diet HL2 than for diet LL2. All four groups showed a considerable loss of body fat during lactation which was not affected by diet. The ability of HL2 rats to catabolize more protein and consume more food allowed them to sustain a greater lactationai performance. Previous maternal protein depletion had no influence on lactationai performance as long as an adequate supply of dietary protein was provided.
Osmotic pressure, water kinetics and volatile fatty acid absorption in the rumen of sheep sustained by intragastric infusions
Authors: López S. , Hovell F. D. DeB. , MacLeod N. A.
Published: June 2005

The effects of changing rumen osmotic pressure (OP) upon water kinetics and volatile fatty acid (VFA) absorption in the rumen of sheep were studied in two 4 × 4 Latin square experiments, each using four lambs with a rumen cannula and an abomasal catheter. In both experiments the lambs were sustained by the intragastric infusion of all nutrients (VFA, Ca, P, Mg and a buffer solution into the rumen, and casein, vitamins and trace elements into the abomasum). On experimental days, which were at least 1 week apart, drinking water and the casein infusion were withdrawn, and the ruminal OP was changed and held constant for 9·5 h, by incorporating NaCl at different concentrations in the buffer solution being infused. In Expt 1 the target OP values were 300, 340, 380 and 420 mosmol/kg, and in Expt 2 were 261 (no saline addition), 350, 420 and 490 mosmol/kg. Using soluble non-absorbable markers (PEG in continuous infusion and Cr-EDTA injected in pulse doses) rumen volume, liquid outflow rates, apparent water absorption through the rumen wall and VFA absorption rates were estimated at six sampling times corresponding to the 1·5 h intervals during the last 7·5 h following the change in rumen OP. Liquid outflow rate (F; ml/h) showed a significant and positive linear relationship with the rumen OP (mosmol/kg), resulting in the equationF= 1·24 OP (SE 0·096)–36·5 (SE 36·6) (r20·96). Similarly, water absorption rate (W; ml/h) was significantly affected by rumen OP, and this relationship was given byW= 395 (SE 39·9) −1·16 OP (SE 0·105) (r20·95), which means that for an OP of 341 mosmol/kg the net movement of water across the rumen wall would be zero, and either a net efflux or a net influx of water would be observed with lower or higher OP respectively. In Expt 2 there was a significant linear effect of OP on rumen volume (P<0·01), with higher OP being associated with increases in rumen liquid contents of about 10–20%. As rumen OP was increased there was also a decline in the absorption rate of VFA (from 232 mmol VFA/h for OP 350 to 191 mmol/h for OP 490 mosmol/kg), resulting in the accumulation of VFA (especially acetate) in the rumen and a consequent fall in rumen pH. Rumen OP seems to be important in defining water movement across the rumen wall and, hence, partitioning between absorption and outflow.
Diurnal changes in large-bowel metabolism: short-chain fatty acids and transit time in rats fed on wheat bran
Authors: Mathers J. C. , Tagny J.-M. Fotso
Published: June 2005

To investigate diurnal changes in large-bowel metabolism rats were fed once daily on a cooked maize-based diet without or with 200 g wLeat bran/kg diet and containing Cr2O3 as an indigestible marker. After 17 d four rats on each diet were killed at 4, 10, 16 and 22 h postfeeding. Emptying of dry matter (DM) from the stomach occurred by an apparently zero-order process at about 0·5 g/h in both diet groups. Feeding wheat bran had little effect on caecal pH or total short-chain fatty acid (SCFA) concentration but was associated with a marked increase in molar proportion of butyrate and a fall in propionate. There were substantial changes in caecal total SCFA concentration and in the molar proportions of individual SCFA throughout the day but no evidence of an interaction between diet and time interval after feeding. Caecal transit time (TT) was significantly reduced by feeding wheat bran whilst colonic TT was unaffected. Although when averaged across both diets there were no significant time effects on caecal or colonic TT, there was a significant diet × time interaction for caecal TT. The extent of coprophagy was measured. The proportion of stomach DM derived from ingested faeces increased with time interval after feeding but it was always a minor contribution so that in these circumstances coprophagy is unlikely to result in significant bias in estimates of digesta flow-rates or TT.
Level of nutrition and age at weaning: effects on humoral immunity in young calves
Authors: Pollock J. M. , Rowan T. G. , Dixon J. B. , Carter S. D.
Published: June 2005

Thirty-two calves were studied to determine the effects of level of nutrition (400 and 1000 g (air-dry matter) milk substitute per d) and age at weaning (5, 9 and 13 weeks) on humoral immune responses measured in serum and bronchoalveolar washings (BAW). All calves were immunized with Keyhole limpet haemocyanin (KLH) at 3 weeks of age, and with horse erythrocytes (HRBC) 1 d after weaning. Feeding the higher level of nutrition compared with the lower level decreased anti-HRBC titres and serum IgG2and IgA responses to KLH (P< 0·05). Weaning at 5 compared with 9 weeks of age decreased serum anti-HRBC responses (P< 0·05), but weaning age had no effect on anti-KLH responses (P> 0·5). Feeding the higher level of nutrition increased total protein (P< 005) and IgG2concentrations (P< 0·01) in BAW. The results showed that variation in husbandry conditions that is within conventional limits affects humoral immune responses in young, artificially-reared calves.
Body composition and fat distribution during the first 2 weeks of gestation in ad lib.-fed and energy-restricted rats
Authors: Sohlström Annica , Kabir Nazma , Sadurskis Aija , Forsum Elisabet
Published: June 2005

Knowledge about changes in body composition during gestation is of interest when estimating energy requirements during pregnancy, and relevant since reproduction is often surprisingly well maintained in malnourished females. Due to difficulties in conducting such studies in humans, studies in rats are of interest. Therefore, maternal retention of fat and fat-free weight was estimated in rats during the first 2 weeks of gestation and during a corresponding time period in virgin controls. Groups fed ad lib. or 70 % of ad lib. intake during the 4 weeks preceding conception and during gestation were studied. Retention was estimated by comparing pregnant and virgin rats with rats killed at the time of conception. Body fat was analysed chemically and fat-free weight was body weight minus body fat. Each rat was divided into twelve to fourteen parts and the fat content of each part was analysed. Pregnant ad lib.-fed rats retained more fat and fat-free weight than did virgin ad lib.-fed controls. In the energy-restricted group the pregnant rats retained more fat-free weight while virgin rats retained slightly more fat than did pregnant rats. The difference between pregnant and virgin rats with respect to the amount of fat in the different body parts was small in both feeding groups. Thus, the statement that fat stored at specific sites in the maternal body represents an important source of energy for use during lactation was not supported. The findings suggest that pregnancy stimulates growth of the maternal body and that chronic moderate energy restriction curtails this growth.
No substantial reduction of the thermic effect of a meal during pregnancy in well-nourished Dutch women
Authors: Spaaij Caroline J. K. , Van Raaij Joop M. A. , Van Der Heijden Lidwien J. M. , Schouten Frans J. M. , Drijvers José J. M. M. , De Groot Lisette C. P. G. M. , Boekholt Harry A. , Hautvast Joseph G. A. J.
Published: June 2005

To investigate changes in the thermic effect of a meal (TEM) during pregnancy, metabolic rate was measured in the fasting state and during the first 180 min after consumption of a standardized test meal in twenty-seven women before, and in each trimester of pregnancy. Resting metabolic rate (RMR) showed a steady increase over pregnancy: values in weeks 24 and 35 of pregnancy were significantly higher than the prepregnancy baseline (Tukey's studentized range test). The pattern of changes of postprandial metabolic rate (PPMR) was similar to that of RMR. Consequently TEM, calculated as PPMR minus RMR, did not change over pregnancy; mean TEM values (kJ/180 min) before and in weeks 13, 24 and 35 of pregnancy were 117 3 (sd 19.4), 116.4 (sd 23.7), 111.6 (sd 24.4) and 111.5 (sd 26.7) respectively. We consider changes in TEM of less than 15% to be of little importance physiologically. If true changes in TEM over pregnancy are 15 % or more we would have had a 90 % chance of observing significant changes in TEM in the present study, given the number of subjects and the methods used. Therefore, we conclude that no substantial reduction in TEM occurs during pregnancy.
Effects of feeding restriction and meal pattern of a sugar beet-containing diet and control diet on nutrient digestibility, plasma lipid concentrations and postprandial triacylglycerol response in broiler chickens
Authors: Razdan A. , Pettersson D.
Published: June 2005

Broiler chickens were fed on a control diet based on maize or a diet containing sugar-beet-pulp fibre (Beeffiber) at an inclusion level of 46 g/kg. Diets were providedad lib. or at a restricted level either once daily or three times daily. On days 13 and 20, chickens fed on thead lib. control and sugar-beet-pulp-containing diets generally weighed more and had poorer feed conversion ratios than chickens given the restricted control and sugar-beet-pulp-containing diets respectively. Furthermore, chickens given the restricted diets once daily had greater body weights and generally improved feed conversion efficiencies compared with chickens given the restricted diets three times daily. Generally, elevated plasma Lipid concentrations were observed amongst chickens given the restricted diets once daily compared with chickens fedad lib. as well as the restricted diets three times daily, while chickens fed on restricted diets three times daily had plasma lipid concentrations intermediate between those fedad lib. and once daily. In a plasma triacylglycerol response study on day 22, feeding of sugar-beet-pulp-containing diets generally reduced postprandial triacylglycerol concentrations and delayed triacylglycerol response relative to chickens given the control diets eitherad lib. or restricted, which may indicate gastrointestinal adaptation to feeding of a fibre-rich diet. Postprandial triacylglycerol concentrations observed for chickens receiving restricted diets were increased compared with chickens given the respectivead lib. diets, indicating adaptation of chickens to reduced feed frequency. On day 25, feeding of sugar-beet-pulp-containing diets decreased digesta dry matter content and ileal organic matter digestibility. Chickens given sugar-beet-pulp-containing diets generally had, on day 25, increased caecal short-chain fatty acid (SCFA) concentrations in comparison with chickens given thead lib. control diet, indicating increased fermentation of dietary components. It is also noteworthy that the greatest SCFA concentrations were observed amongst chickens given the control diet once daily, suggesting enhanced caecal fermentation capacity. This may have been a consequence of increased bacterial activity and caecal hypertrophy due to infrequent feeding of a low-fibre diet.
The effect of triacylglycerol fatty acid positional distribution on postprandial plasma metabolite and hormone responses in normal adult men
Authors: Zampelas A. , Williams Christine M. , Morgan Linda M. , Wright J. , Quinlan P. T.
Published: June 2005

The present study has examined the possibility that the positional distribution of fatty acids on dietary triacylglycerol (TAG) influences the postprandial response to a liquid meal in adult subjects. Postprandial TAG, non-esterified fatty acids (NEFA), ketones, glucose, insulin and gastric inhibitory polypeptide (GIP) responses were monitored in sixteen normal adult male subjects over 6 h following consumption of test meals containing dietary TAG in which palmitic acid was predominantly on the sn-1 (Control) or sn-2 positions (Betapol). Plasma total TAG, chylomicron-rich TAG and chylomicron-poor TAG concentrations were identical in response to the two test meals. The peak increase (mean (sd)) in chylomicron TAG was 0 85 (0 46) mmol/l after the Control meal and 0 85 (0 42) mmol/l after the Betapol meal. Plasma glucose, insulin, GIP, NEFA and ketone concentrations were also very similar following the two meals. It is concluded that dietary TAG containing saturated fatty acids on the sn-2 position appear in plasma at a similar level and over a similar timescale to TAG in which saturated fatty acids are predominantly located on sn-1 or sn-3 positions. The results reported in the present study demonstrate that the positional distribution of fatty acids on dietary TAG is not an important determinant of postprandial lipaemia in adult male subjects, but do not exclude the possibility that different responses may occur when these dietary TAG are given long term.
The effect of zinc deficiency on wool growth and skin and wool follicle histology of male Merino lambs
Authors: White C. L. , Martin G. B. , Hynd P. I. , Chapman R. E.
Published: June 2005

The aims of this work were to quantify the requirements of Zn for wool growth in growing male Merino lambs, and to describe the histological lesions of Zn deficiency in skin and wool follicles. Four groups of male Merino lambs (n 4) weighing 22 kg were fed ad lib. for 96 d on diets that contained 4 (basal diet), 10, 17 or 27 mg Zn/kg. Sheep in a fifth group were fed on the diet containing 27 mg Zn/kg, but were pair-fed to sheep on the 4 mg Zn/kg diet. Zn was added to the basal diet as ZnSO4 to give the respective treatment concentrations. Sheep fed on the diet containing 4 mg Zn/kg showed clinical signs of Zn deficiency and lower feed intakes and wool growth than sheep in the other groups. Their wool fibres were improperly keratinized and the wool follicles contained a higher proportion of apoptotic bodies than other groups. There was no evidence of parakeratosis and the rate of bulb-cell production was not affected. Sheep from other groups showed no clinical signs of Zn deficiency, and mean feed intakes and growth rates did not differ significantly between sheep fed on diets containing 10, 17 or 27 mg Zn/kg. However, wool growth was reduced in sheep fed on the diet containing 10 mg Zn/kg compared with those fed on diets containing 17 or 27 mg/kg. The mean concentration of Zn in the plasma at which wool growth was 90 % of maximum was 0.5 mg/l. The equivalent value for the diet was 12 mg/kg, with 95 % confidence intervals of 8 to 16 mg/kg. The results suggest that Zn deficiency reduces wool growth through a specific mechanism, perhaps involving impaired protein synthesis.
Seasonality in digestion and rumen metabolism in red deer (Cervus elaphus) fed on a forage diet
Authors: Freudenberger D. O. , Toyakawa K. , Barry T.N. , Ball A. J. , Suttie J. M.
Published: June 2005

Six adult castrated male red deer (Cervus elaphus), fitted with rumen cannulas, were offered chaffed lucerne hay ad lib. during winter and summer, with voluntary food intake (VFI) being respectively 59 and 89 g dry matter intake (DMI)/kg bodyweight 0.75 per d. The same animals were also offered the same feed during summer, with intake restricted to that of winter VFI. The apparent digestibility of gross energy (0.60) or fibre (0.41) and the total capacity (volume) of the rumen were unaffected by season or level of intake. Relative to winter ad lib. feeding, N retention, total rumen pool size (DM +water), rumen pool size as a proportion of capacity, and rumen total volatile fatty acid (VFA) pool size were increased during summer ad lib. feeding. Relative to winter ad lib. feeding, N retention, rumen ammonia irreversible loss rate (IRL), total rumen pool size, rumen pool size as a proportion of capacity, and rumen ammonia and total VFA pool sizes were also increased during summer restricted feeding. Rumen Lignin fractional disappearance rate (FDPR) was lower in summer than in winter, and there was a nonsignificant trend for rumen fractional outflow rate (FOR) of liquid to follow the same trend. Molar proportions of acetate and propionate were unaffected by season, proportions of n-butyrate were slightly higher in summer, and proportions of iso-butyrate and iso-valerate were higher for summer restricted than for winter ad lib. feeding. When intakes were equalized there were no seasonal changes in rate of rumen water outflow, net rumen water balance or intestinal water absorption. It is concluded that there is a seasonal change in rumen physiology in red deer during summer causing increased total rumen pool size (DM + water), an increase in rumen ammonia production and pool size, and an increase in rumen total VFA pool size which are all independent of the increase in VFI. The increased total rumen pool size in the summer restricted group may indicate an increased mean retention time (MRT) of digesta in the rumen. MRT for particulate matter was calculated to be 29.2 and 34.8 h during winter and summer respectively. This, together with increased rumen ammonia production, may function to maintain rumen fibre digestion when VFI normally increases during summer. The increased rumen VFA pool size may indicate increased VFA production during summer, in the same way as ammonia IRL was increased.
Passive uptake in the small intestine and active uptake in the hindgut contribute to the highly efficient mineral metabolism of the common mole-rat, Cryptomys hottentotus
Authors: Pitcher Tammy , Buffenstein Rochelle
Published: June 2005

Cryptomys hottentotus has no access to dietary or endogenous sources of cholecalciferol (D3). Serum concentrations of calcifediol (25(OH)D3) were undetectable (< 5 ng/ml) and calcitriol (1,25(OH)2D3), although detectable in plasma, was at a low concentration (31.40) (SEM 3.06 pg/ml). Despite their naturally impoverished vitamin D status, these animals exhibited highly efficient mineral absorption processes (Ca apparent fractional absorption efficiency, AFA (%) 95.33 (SEM 1.36); inorganic P (Pi) AFA (%) 93.49 (SEM 0.81)). Furthermore, plasma mineral content was tightly regulated (Ca 2.57 (SEM 0.08) mmol/l; Mg 1.23 (SEM 0.05) mmol/l; Pi 2.12 (SEM 0.15) mmol/1). Mode of uptake in C. hottentotus was unlike that in other D3-replete mammals. First, passive (rather than active) uptake occurred in the traditional site of active Ca absorption (with serosal: mucosal (S:M) ratios in the duodenum of 1.32 (SEM 0.13)), and the only site of active Ca uptake was the hindgut (caecum S:M 3.35 (SEM 0.46); proximal colon S:M 2.13 (SEM 0.30)). Despite the presence of active uptake in these hindgut regions, their overall contribution to the daily rate of mineral absorption was small (9.53 (SEM 1.27)%). These underground inhabitants rely upon highly efficient, passive mineral uptake. This is adequate to meet their mineral requirements and maintain mineral homeostasis in the absence of vitamin D.
Calcium absorption and bone utilization in spontaneously hypertensive rats fed on native and heat-damaged casein and soya-bean protein
Authors: Yuan Yvonne V. , Kitts David D.
Published: June 2005

The effects of dietary protein on Ca bioavailability and utilization in bone were examined in male spontaneously hypertensive rats (SHR) fed on diets containing either casein (200 g/kg (control), 60 g/kg or heat-damaged (HD) 200 g/kg) or soya-bean protein isolate (200 g/kg (control), 60 g/kg, or HD 200 g/kg). Casein was heat-damaged to limit caseinophosphopeptide (CPP) production in order to evaluate casein enhancement of Ca bioavailability. All diets contained an adequate level of Ca (5 g/kg). A 24 h mineral balance study was performed when animals were 10 weeks old, followed by measurement of in situ paracellular Ca disappearance, femur mineralization and biomechanics at 14 weeks of age. Digestibility of soya-bean and both HD proteins estimated in vitro was reduced compared with native casein. Animals fed on HD and 60 g/kg protein diets exhibited decreased (P < 0.05) body weight gain, dry matter intake and feed efficiency compared with controls. The ileal disappearance of 45Ca was lower (P < 0.05) in animals fed on HD casein and all the soya-bean protein diets. Ca balance was not strongly affected by dietary treatments. A significant (P < 0.05) interaction between protein source and reduced protein intake was observed for femur calcification and physical measurements. Femur bending failure energy and biomechanical force measurements were reduced (P < 0.05) in HD and 60 g/kg casein and soya-bean protein fed animals. These findings suggest that whole-body Ca homeostatic mechanisms were involved in compensating for reduced Ca bioavailability and retention from casein diets modified to reduce protein digestibility and CPP production.
Effect of food intake on energy and protein metabolism in the skin of Romney sheep
Authors: Harris P. M. , Lee J. , Sinclair B. R. , Treloar B. P. , Gurnsey M. P.
Published: June 2005

Sheep fed on either a low (500 g lucerne (Medicago sativa) chaff/d; L) or high (1100 g lucerne chaff/d; H) intake had measurements made, using arterio–venous techniques, of blood flow and energy metabolite and cysteine utilization in the skin. Sheep on the H intake had significantly increased skin blood flow (P = 0.014) and oxygen uptake (P = 0.05). Although the H sheep had higher skin blood flow they showed no difference in skin uptake of either glucose or acetate compared with the L sheep, but the H sheep had a significantly lower output of lactate (P = 0.014). Animals in each group had either [14Clglucose or [14Clacetate infused into the skin which showed that acetate was the predominant precursor of skin sterol and fatty acid synthesis in the H sheep while L sheep skin used both glucose and acetate. The H sheep showed an increase in the net uptake of cysteine by the skin (P = 0.053), and in the uptake of cysteine for protein synthesis (P = 0.078), relative to the L sheep and this increase was of a comparable magnitude to the increase in blood now to the skin. Although blood flow, protein synthesis and energy supply increased in the skin of the H sheep by 200–300%, wool production would only have increased by 10–20 %, suggesting that nutrient flux changes are not the sole level of regulation of wool production.
Breath hydrogen after ingestion of the bulk sweeteners sorbitol, isomalt and sucrose in chocolate
Authors: Lee Adam , Zumbe Albert , Storey David
Published: June 2005

The effect of eating chocolate containing sugar alcohols as sweetening agents on colonic fermentation has been investigated by monitoring breath H2levels. Levels were compared with those occurring after the consumption of normal, sugar-containing chocolate. Ten healthy volunteers aged 19 to 21 years ingested equal amounts of either sorbitol, isomalt or sucrose incorporated into standard chocolate bars. Breath H2levels after consumption of chocolate containing either sorbitol or isomalt were significantly higher than those after consumption of chocolate containing sucrose (P< 0.001). After consumption of chocolate containing sorbitol, double the mean estimated volume of breath H2was produced over 6 h compared with that produced after eating chocolate containing isomalt. Taken together with results relating to the incidence of intolerance symptoms, these findings demonstrate that sorbitol is associated with greater colonic fermentation compared with isomalt.
Influences of dietary and intraduodenal lipid on alertness, mood, and sustained concentration
Authors: Wells Anita S. , Read Nicholas W. , Craig Angus
Published: June 2005

The effects of intraduodenal and dietary lipid on alertness, mood and performance in a task requiring sustained attention were investigated in two studies. The first experiment compared the effect of duodenal infusion of either 100 g/l Intralipid (8·36 kJ/min) or isotonic saline (9 g NaCl/l) in paired studies carried out on two non-consecutive days on five male volunteers. Two consecutive 3 h infusions, one of lipid, the other saline, were given blind on each day using a crossover design. Analysis of variance indicated that lipid significantly reduced alertness (P < 0·05) and affected the speed and accuracy of performance in a sustained attention task (P < 0·05). A second experiment compared the effects on eight male volunteers of two isoenergetic lunches of similar appearance, taste and protein content but differing fat and carbohydrate (CHO) contents (fat energy:CHO, 64:18 v. 7:76). Alertness was lower (P < 0·05) and responses to stimuli in a sustained attention task were slower after the high-fat meal than after the low-fat meal (P < 0·05). In conclusion, infusion of lipid into the small intestine, and the substitution of fat for carbohydrate while keeping energy and protein constant in a lunch, both cause an enhanced postprandial decline in alertness and concentration. This may be related to the presence of lipid in the small intestine.
A recipe-based, diet-planning modelling system
Authors: Leung Pingsun , Wanitprapha Kulavit , Quinn Lynne A.
Published: June 2005

In a recent article in the British Journal of Nutrition, Sklan & Dariel (1993) presented a method for diet planning employing a mixed-integer programming algorithm for meeting nutritional requirements at minimum costs for institutions or individuals. They recognized that most food items are generally consumed in whole units and as such they are represented as integer variables. However, as in most previous studies, they derived the minimum cost diets by optimizing over purchased food items. The present paper presents a computer-assisted, diet-planning modelling system for individuals by optimizing over recipes instead of food items. This is accomplished by restricting the integer programming solutions to those bundles of food that represent reasonably popular meal recipes. The modelling system is composed of three main components: recipe data entry, database management, and the model. The recipe data entry component creates and stores recipes. It aiso provides nutritional analysis of the recipes. The database management component creates and maintains several databases necessary to build the modelling data file. The modelling component solves the user-specified model. Currently, the model component can solve for the optimal diet by minimizing cost or minimizing cooking and preparation time. The optimal diet is prepared to satisfy the recommended nutritional guidelines for a predefined group of individuals for 1 week. The system currently has 895 popular recipes found in Hawaii. Diet plans generated using this modelling system with differing objectives are discussed and compared.
Do breeds of pig differ in the efficiency with which they use a limiting protein supply?
Authors: Kyriazakis I. , Emmans G. C.
Published: June 2005

An experiment was designed to test the prediction that two genetically-very-different kinds of pigs would retain the same amounts of protein in their bodies when given the same allowances of the same feed for the same period of time, when these allowances were limiting for both. An allowance of 33·957 kg of a feed with 12·76 MJ metabolizable energy (ME) and 189 g crude protein (N × 6·25)/kg feed was given to Large White × Landrace (LW ×) and Chinese Meishan (CM) female pigs over three different periods of time: (1) ad lib. (AL) with the time taken by individual pigs to consume the allowance being a variable, (2) over a period of 7 weeks (H) and (3) over a period of 9 weeks (L). In addition, in a fourth treatment, pigs of both breeds received the same allowance but supplemented with starch also over a period of 7 weeks (HS). The performance of the pigs on treatment AL was affected by pig breed, with CM pigs gaining protein at a slower, and lipid at a faster, rate than LW × pigs. On treatments L, H and HS the average amounts of protein retained were 2·693 and 2·655 kg for the LW × (n 15) and CM (n 15) pigs respectively (SED 0·106 kg). There was a statistical indication that the LW × pigs may have been more efficient on L, and less efficient on HS, than the CM pigs but we have been unable to propose any biological reason for such an effect, if it was in fact a real one. Thus, the efficiency with which ideal protein was utilized was close to being constant, and apparently at its maximum, for the two breeds. However, although CM pigs had the same protein gain, and the same live weights, on the same feed allowances as the LW × pigs, they gained significantly more lipid. This was attributed in part to their digesting their feed better and in part to their having a lower energy requirement for maintenance through a lower level of physical activity. Given that these two very different kinds of pigs use limiting protein with the same efficiency, it is suggested that it is safe to make the assumption in models of pig growth that the material efficiency of using limiting protein is constant across genotypes of pig.
Effect of propionate on fatty acid and cholesterol synthesis and on acetate metabolism in isolated rat hepatocytes
Authors: Demigné Christian , Morand Christine , Levrat Marie-Anne , Besson Catherine , Moundras Corinne , Rémésy Christian
Published: June 2005

In the present study the actual role of propionic acid in the control of fatty acid and cholesterol synthesis was investigated in isolated liver cells from fed rats maintained in the presence of near-physiological concentrations of glucose, glutamine and acetate. Using3H2O for lipid labelling, propionate appears as an effective inhibitor of fatty acid synthesis and to a lesser extent of cholesterol synthesis, even at the lowest concentration used (0·6 mmol/l). Butyrate is a potent activator of both synthetic pathways, and the activating effect was not counteracted by propionate. Using 1-[14C]acetate, it was observed that propionate at a moderate concentration, or 1 mmol oleate/l, are both very effective inhibitors of14C incorporation into fatty acid and cholesterol. This incorporation was drastically inhibited when propionate and oleate were present together in the incubation medium. The net utilization of acetate by rat hepatocytes was impaired by propionate, in contrast to oleate. 1-[14C]butyrate was utilized at a high rate for fatty acid synthesis, but to a lesser extent for cholesterol synthesis; both processes were unaffected by propionate. Intracellular citrate concentration was not markedly depressed by propionate, whereas it was strongly elevated by butyrate. In conclusion, propionate may represent an effective inhibitor of lipid synthesis when acetate is a major source of acetyl-CoA, a situation which is encountered with diets rich in readily-fermentable fibres. The present findings also suggest that propionate may be effective at concentrations close to values measuredin vivoin the portal vein.
Taurocholic acid adsorption during non-starch polysaccharide fermentation: anin vitrostudy
Authors: Gelissen Ingrid C. , Eastwood Martin A.
Published: June 2005

The association of radiolabelled taurocholic acid with the solid fraction of a faecal fermentation mixture was measured. A human faecal inoculum was incubated with [24-14C]taurocholic acid and several non-starch polysaccharide sources (pectin, wheat bran, ispaghula (Plantago ovata) husk and seed), glucose or a substrate-free control. Portions of fermentation mixture were taken at 0, 3, 6, 21 and 24 h and centrifuged to acquire a supernatant fraction and a pellet containing the fermentation residue.14C was measured in supernatant fractions and pellets at all time points. Volatile fatty acids (VFA) were measured at 0 and 24 h to confirm bacterial growth. Radioactivity in the pellet increased over time for all substrates. Glucose resulted in the greatest incorporation of taurocholic acid into the pellet, followed by pectin. At 24 h the proportion of the total radioactivity found in the pellet was 92% for glucose, 79% for pectin, 60% for wheat bran, 59% for ispaghula seed, 53% for ispaghula husk and 26% for the control (mean of duplicates). Glucose and pectin produced the greatest quantity of VFA at 24 h. VFA production was highly correlated with radioactivity in the pellet (r0·976,P<0·005). These results suggest that the bile acid binding capacity of a faecal culture mixture may be strongly influenced by the fermentability of the available substrate and hence related to bacterial metabolic activity.
Biochemical validation of a self-administered semi-quantitative food-frequency questionnaire
Authors: Porrini M. , Gentile M. G. , Fidanza F.
Published: June 2005

The present study is a biochemical validation of a food-frequency questionnaire (FFQ) with optical reading, i.e. containing food portion photographs to help to assess quantities. Forty-four healthy subjects, non-smokers and not taking vitamin supplements, were recruited for the study. After completion of the questionnaire, subjects were asked to keep a 7 d weighed dietary record (7DR). Three 24 h urine samples were collected on 3 different days over the week of food recording for the analysis of urea-N, P and K. On the 4th day of food recording, blood was collected for determination of α-tocopherol, β-carotene and ascorbic acid. N, P and K determined in urines and from 7DR were significantly correlated (Spearman rank correlation test),rvalues being 0·77, 0·57 and 0·42 respectively. The correlations with the FFQ were significant only for N (r0·45) and P (r0·39). Blood ascorbic acid and β-carotene concentrations correlated with dietary intake when determined from 7DR (bothr0·44), but not when determined from FFQ. No correlation was found for α-tocopherol. The data obtained seem to prove the validity of the FFQ in defining eating patterns in terms of some nutrients, but not vitamins, at least as far asaq non-supplemented subjects are concerned. The way in which foods were grouped in the questionnaire could account for these results.
Lipid peroxidation, prostacyclin and thromboxane A2in pigs depleted of vitamin E and selenium and supplemented with linseed oil
Authors: Nolan Maeve R. , Kennedy Seamus , Blanchflower W. John , Kennedy D. Glenn
Published: June 2005

In a 2×2 balanced factorial experiment the biochemical effects on pigs of two dietary factors were investigated. The first factor was α-tocopherol and Se supplementation and the second factor was supplementation with α-tocopherol-stripped linseed oil. In pigs fed on diets depleted of α-tocopherol and Se, increases in concentrations of markers of lipid peroxidation (4-hydroxynonenal and hexanal) were observed. However, skeletal myopathy was only observed in those pigs fed on diets depleted of α-tocopherol and Se and supplemented with oil. In those pigs, increased lipid peroxidation was observed in heart andsupraspinatusmuscle. The plasma concentration of thromboxane B2was increased in pigs fed on diets depleted of α-tocopherol and Se, suggesting an increased tendency towards platelet aggregation. However, this change was reversed in pigs depleted of α-tocopherol and Se, but supplemented with oil. This may have been a consequence of loss of arachidonic acid, the substrate for thromboxane formation, as a result of lipid peroxidation.
Effects of dietary fatty acid composition on basal and hormone-stimulated hepatic lipogenesis and on circulating lipids in the rat
Authors: Zampelas Antonios , Morgan Linda M. , Furlonger Nigel , Williams Christine M.
Published: June 2005

Thirty male rats were randomly assigned to one of three dietary groups in which the source of dietary fat was either a mixed oil, maize oil or fish oil. Effects of dietary fatty acid composition onin vitrorates of [U-14C]glucose incorporation into hepatic total lipids and into hepatic triacylglycerol were measured under basal, insulin (4 nM)-, gastric inhibitory polypeptide (GIP; 6 nM)- and insulin + GIP (4 nM + 6nM)-stimulated conditions. Effects of the three diets on postprandial plasma triacylglycerol, cholesterol, insulin and GIP concentrations were also measured. The fish-oil diet decreased rates of basal glucose incorporation into hepatic total lipids (P< 0·05) and hepatic triacylglycerol (P< 0·01) compared with the mixed-oil diet. The presence of insulin and GIP in the incubation medium stimulated glucose incorporation into hepatic total lipids in the maize-oil (P< 0·01) and fish-oil groups (P< 0·05), as well as into hepatic triacylglycerol in the maize-oil group (P< 0·005). In addition, the fish-oil diet decreased postprandial plasma triacylglycerol levels compared with both other dietary groups (P< 0·05 both cases), and the mixed-oil diet markedly increased postprandial plasma insulin levels compared with the other dietary groups (P< 0·001).
Zinc absorption in adult humans: the effect of iron fortification
Authors: Davidson Lena , Almgren Annette , Sandström Brittmarie , Hurrell Richard F.
Published: June 2005

The effect of Fe fortification on the absorption of Zn was studied by radioisotopic labelling of single meals, followed by measurements of whole-body retention of65Zn at 14 d after intake. Healthy adult volunteers participated in the study. Weaning cereal, wheat bread and infant formula, foods that are all frequently Fe-fortified, were evaluated in the study. The amounts of Fe added as FeSO4were similar to the levels in commercial products in Europe and the USA, and were 200 or 500 mg Fe/kg (weaning cereal), 65 mg Fe/kg (white wheat flour) and 12 mg Fe/1 (infant formula). For comparison, Zn absorption was measured in the same subjects, from identical test meals containing no added Fe. No statistically significant differences were found when Zn absorption from the Fe-fortified test meals was compared with that from non-Fe-fortified test meals. Fractional Zn-absorption values from Fe-fortifiedv. non-fortified meals were 31·1 (sd 1·19)v. 30·7 (SD 7·0)% (weaning cereal; 200 mg Fe/kg), 37·7 (SD 16·6)v. 30·2 (SD 9·9)% (weaning cereal; 500 mg Fe/kg), 36·5 (SD 14·4)v. 38·2 (SD 18·1)% (bread; 65 mg Fe/kg flour) and 41·6 (SD 8·1)v. 38·9 (SD 14·5)% (infant formula; 12 mg Fe/1). The addition of Fe to foods at the currently used fortification levels was thus not associated with impaired absorption of Zn and the consumption of these Fe-fortified foods would not be expected to have a negative effect on Zn nutrition.
The effect of the gel-forming liquid fibre on feeding behaviour in man
Authors: Tomlin J.
Published: June 2005

A novel substance called liquid fibre (LF) has been developed which gels in the stomach and dramatically delays gastric emptying. The prolonged stomach distension LF causes would be expected to reduce food intake. The present study tested whether LF affected psychological factors connected with eating behaviour and short-term food intake. Paired studies were carried out on seventeen healthy but overweight volunteers (ten male, seven female) with body mass indices of 24–34 kg/m2 who were non-restricted eaters. On one occasion (randomized) they took drinks of LF (300 ml each) at 09·05, 11·55 and 18·00 hours, and on the other they took placebo drinks. Subjective feelings were assessed by visual analogue scales. The amount of food consumed at an appetizing pre-selected meal presented at 12·15 hours was measured covertly. Food diaries were kept until 16·00 hours on the following day. The visual analogue scales indicated that LF reduced hunger and the amount of food desired, and increased fullness, all of which would be expected to cause a reduction in food intake. However, there were no differences in the amount or type of food eaten at the appetizing test-meal (6073 v. 5824 kJ, P = 0·41). Food eaten later in the day was significantly delayed by LF (7·0 v. 5·9 h, P = 0·030), and the amount tended to be reduced (4328 v. 5439 kJ, P = 0·088). The energy consumed on the following day also tended to be lower after LF (3802 v. 4737 kJ, P = 0·130). This suggests that gastric distension is a relatively unimportant influence on eating behaviour when non-restricted eaters are presented with an appetizing meal and that intestinal factors seem more important for prolonging satiety and reducing subsequent food intake.