bluuebunny/crossref_metadata_2025 huggingface dataset:
High α-linolenic acid flaxseed (Linum usitatissimum):some nutritional properties in humans
Authors: Cunnane Stephen C. , Ganguli Sujata , Menard Chantale , Liede Andrea C. , Hamadeh Mazen J. , Chen Zhen-Yu , Wolever Thomas M. S. , Jenkins David J. A.
Published: June 2005

Although high α-linolenic acid flaxseed (Linum usitatissitmum) is one of the richest dietary sources of α- linolenic acid and is also a good source of soluble fibre mucilage, it is relatively unstudied in human nutrition. Healthy female volunteers consumed 50 g ground, raw flaxseed/d for 4 weeks which provided 12–13% of energy intake (24–25 g/100 g total fat). Flaxseed raised α-linolenic acid and long-chainn-3 fatty acids in both plasma and erythrocyte lipids, as well as raising urinary thiocyanate excretion 2.2- fold. Flaxseed also lowered serum total cholesterol by 9 % and low-density-lipoprotein-cholesterol by 18%. Changes in plasma α-linolenic acid were equivalent when 12 g α-linolenic acid/d was provided as raw flaxseed flour (50 g/d) or flaxseed oil (20 g/d) suggesting high bioavailability of α-linolenic acid from ground flaxseed. Test meals containing 50 g carbohydrate from flaxseed or 25 g flaxseed mucilage each significantly decreased postprandial blood glucose responses by 27%. Malondialdehyde levels in muffins containing 15 g flaxseed oil or flour/kg were similar to those in wheat-flour muffins. Cyanogenic glycosides (linamarin, linustatin, neolinustatin) were highest in extracted flaxseed mucilage but were not detected in baked muffins containing 150 g flaxseed/kg. We conclude that up to 50 g high-α-linolenic acid flaxseed/d is palatable, safe and may be nutritionally beneficial in humans by raisingn-3 fatty acids in plasma and erythrocytes and by decreasing postprandial glucose responses.
The digestion process of the sugar alcohol isomalt in the intestinal tract of the pig
Authors: Van Weerden E. J. , Huisman J.
Published: June 2005

In a study with ten pigs of 60–70 kg live weight, provided with a re-entrant cannula at the end of the ileum, and sixteen intact, non-cannulated pigs, the digestion and absorption of a dietary dose of 100 g isomalt/kg, and isomalt given between the meals as a ‘sweet’on the basis of 50 and 100 g/kg feed consumption, were examined. In all three isomalt treatments slightly less than 0.40 of the isomalt consumed was digested in the small intestine when the calculations were based on ileal sugar passage. However, when basing the calculations on energy contents of ileal chyme, only approximately 0.10 was digested in the small intestine. The bacterial fermentation of the isomalt flowing into the large intestine was indicated by a decreased faecal energy digestibility and a slight reduction in faecal dry matter and nitrogen digestibility. The retention of the minerals sodium, potassium, magnesium, calcium and phosphorus was not influenced to any measurable extent when isomalt was fed.
Complex carbohydrate digestion and large bowel fermentation in rats given wholemeal bread and cooked haricot beans (Phaseolus vulgaris) fed in mixed diets
Authors: Key Flona B. , Matherst J. C.
Published: June 2005

The digestion of non-starch polysaccharides (NSP) and of resistant starch (RS) by rats fed on wholemeal-bread-based diets containing 0-450 g cooked, freeze-dried haricot beans (Phaseolus vulgavis)/kg diet was measured over the final 14 d of a 21 d feeding experiment. The bread and beans provided all the dietary polysaccharide. RS could not be detected consistently in faeces and it was assumed that this fraction was entirely fermented in the large bowel (LB). NSP digestibilities were 0.56 and 0.86 for wholemeal bread and beans respectively with no evidence that the dietary presence of beans affected digestibility of bread NSP. Bean non-cellulosic polysaccharides were highly digestible with values of 0.98, 0.88 and 0.99 for arabinose, xylose and uronic acids components respectively. There were large increases in organic matter flow to the LB when beans were fed which was associated with marked caecal hypertrophy and alterations in caecal volatile fatty acids (VFA) pattern. Calculated VFA absorption from the LB was 5-fold higher with the highest level of beans and this was reflected in higher concentrations of VFA in portal and heart blood.
Assessment of fermentation in growing pigs given unmolassed sugar-beet pulp: a stoichiometric approach
Authors: Zhu J. Q. , Fowler V. R. , Fuller M. F.
Published: June 2005

In four experiments growing pigs were given a cereal-based diet alone or supplemented with unmolassed sugar-beet pulp (SBP), used as a model substrate for fermentation. The rates of production of methane and gaseous hydrogen were measured and, together with the molar proportions of volatile fatty acids (VFA) in the digesta, used in stoichiometric calculations of fermentation. The resulting estimates were only one-sixth of the observed extent of digestion of SBP. Bacteriostatic levels of antibiotics reduced fermentation by more than half, as judged from the digestion of non-starch polysaccharides: allowing for the incomplete suppression of fermentation it was estimated that the production of methane and VFA could account completely for the digested SBP. The potential contribution of various routes of hydrogen disposal to the error of the stoichiometric calculations is discussed.
The effect of dietary calcium intake in weanling rats on the efficiency of calcium absorption
Authors: Fairweather-Tait Susan J. , Johnson Amanda , Wright A. J. A.
Published: June 2005

Rats were weaned onto high (HCa, 14.6 g/kg)- or low (LCa, 3.88 g/kg)-Ca diets for 12 d and the efficiency of absorption of Ca measured from 20 mg Ca (as CaCl2, labelled with 47Ca) by means of wholebody counting. The LCa group absorbed 74 % of the test dose and the HCa group 60 % of the test dose (P < 0.001). All animals were then given the LCa diet for 6 weeks and the absorption test repeated. This time there was no difference in efficiency of absorption (HCa 54%, LCa 57%). The femur dry weight was significantly lower in the group initially fed on the LCa diet, but the Ca concentration was similar to that of the HCa group. The results do not lend support to the suggestion that early dietary exposure to Ca manifests itself as a difference in Ca metabolism in later life. They do, however, highlight the importance of adequate Ca intake during critical periods of growth.
Inhibition of haem-iron absorption in man by calcium
Authors: Hallberg Leif , Rossander-Hulthèn Lena , Brune Mats , Gleerup Ann
Published: June 2005

The inhibiting effect of Ca on non-haem-Fe absorption is well established. Presentstudies showed that Ca inhibited haem-Fe absorption to the same extent when the same amount of Ca (165 mg Ca as CaCl2) was added to a meal. Attempts were made to examine the mechanism for this inhibition in the present studies. Meat is the only known dietary factor influencing haem-Fe absorption. The present studies were designed to examine whether Ca interfered with the enhancing effect of meat on haem-Fe absorption. We found that the inhibition was the same whether biosynthetically radio-Fe-labelled haemoglobin wasgiven in meals with or without meat. The haem-Fe absorption ratio with: without added Cawas 0.59 (SE 0.07) when Ca was added to a hamburger meal, and 0.052 (se 0.03) when added to a wheat roll. These values were not significantly different (t 0.95; P = 0.35). The inhibition of haem-Fe absorption by Ca is, thus, a direct effect on theabsorption of haem-Fe and not an indirect counteracting effect of the well-known enhancing effect of meat on haem-Fe absorption. Control studies were conducted to ensure that haem-Fe had not been degraded to non-haem-Fe during preparation of the foods. Since Ca inhibits the absorption of haem- and non-haem-Fe to the same extent, the present results strongly suggest that Ca interferes with the transport of Fe through the mucosal cell, andata late stage, is common for haemand non-haem-Fe transport. The observations that Ca strongly interferes with the absorption of both haem- and non-haem-Fe have important nutritionalimplications.
A proposed intestinal mechanism for the effect of riboflavin deficiency on iron loss in the rat
Authors: Powers Hilary J. , Weaver Lawrence T. , Austin Steven , Beresford John K.
Published: June 2005

The effect of riboflavin deficiency on gastrointestinal Fe distribution and loss was studied in weanling rats. Riboflavin deficiency was associated with a significant increase in crypt depth in the upper and mid small intestine and a twofold increase in the rate of crypt cell production compared with weight-matched andad lih.-fed control rats. The rate of loss of endogenous Fe, measured as faecal59Fe after intraperitoneally administered59Fe, was twice that from riboflavin-deficient rats compared with weightmatched controls. We suggest that while there may be a contribution from turnover of enterocytes with an enhanced Fe content, enhanced Fe loss associated with riboflavin deficiency is due predominantly to an accelerated rate of small-intestinal epithelial turnover.
Vitamin C intake and plasma ascorbic acid concentration in adolescents
Authors: Finglas P. M. , Bailey Angela , Walker A. , Loughridge Julie M. , Wright A. J. A. , Southon Susan
Published: June 2005

The relationship between vitamin C intake and status was investigated in a group of adolescents (13–14 years old). Dietary intakes were assessed using a 7 d weighed dietary record method, coupled with the collection of duplicate diets. Vitamin C intakes calculated using food composition tables were compared with values obtained by direct analysis of duplicate diets. Vitamin C status was judged via measurement of plasma ascorbic acid (AA) concentration in blood samples taken after a 12–15 h fast. The relationship between calculated and analysed vitamin C intake and plasma AA concentration was examined. Average daily calculated vitamin C intakes, for the group (n54) as a whole over a 7 d period, gave a good estimate of intake, as judged by prompt analysis of duplicate diets. However, analysedv. calculated intakes were significantly different for approximately one-third of subjects when data were examined on an individual basis. Large discrepancies between analysed and calculated values could not be accounted for on a food group basis. In all but two individuals, calculated vitamin C intake was in excess of the new reference nutrient intake (RNI, part of the new daily reference values (Department of Health and Social Security, 1991)) of 40 mg and all plasma AA concentrations were well above those used to indicate even a moderate risk of deficiency. A relationship between vitamin C intake and plasma AA was observed for both males (n19) and females (n35). However, the relationship was much stronger for males who showed a wider range of both intake and plasma AA values.
Long-term supplementation with selenate and selenomethionine: Selenium and glutathione peroxidase (EC1.11.1.9) in blood components of New Zealand women
Authors: Thomson Christine D. , Robinson Marion F. , Butler Judy A. , Whanger Phllip D.
Published: June 2005

Thirty-three New Zealand women aged 18–23 years received daily for 32 weeks, 200 μg Se as Seenriched yeast (selenomethionine), or brewer's yeast mixed with selenate, or no added Se (placebo) in a double-blind trial. Se supplementation raised (P= 0.001), platelet glutathione peroxidase (EC1.11.1.9; GSHPx) activity, and also Se and GSHPx in whole blood, erythrocytes and plasma. Selenomethionine was more effective in raising blood Se concentrations than selenate, but both were equally effective in raising GSHPx activities in whole blood, erythrocytes and plasma, indicating a similar bioavailability for the two forms. These observations and those of gel filtration studies of erythrocytes and plasma proteins reported elsewhere (Butleret al.1991) are consistent with the incorporation of Se from selenomethionine into a general tissue protein pool while selenate is directly available for GSHPx synthesis, and explain the poorer correlation between Se and GSHPx in individuals with higher Se status. However, selenate raised platelet GSHPx activities to a greater extent than did selenomethionine suggesting some other effect of selenate on platelets which needs further investigation. A response of GSHPx activity in these New Zealand subjects indicates that their dietary Se intake is insufficient to meet recommended intakes based on the criterion of saturation of GSHPx activity, and could reflect a marginal Se status. The level of blood Se necessary for saturation of GSHPx of about 100 ng Se/ml whole blood confirms observations in earlier studies.
Glutathione content of the small intestine: regulation and function
Authors: Kelly Frank J.
Published: June 2005

In ad lib.-fed rats the epithelium of the small intestine, like the liver, contains large quantities of glutathione, 17.0 and 32.4 nmol/mg protein respectively. Following 24 h food restriction the glutathione content in both tissues fell 53 and 69% respectively. Unlike the liver, however, the glutathione content of the intestinal mucosa is not regulated to a diurnal rhythm, suggesting that the liver may provide glutathione or glutathione precursors to maintain intestinal glutathione levels. Intestinal epithelial cell preparations obtained from 24 h food-deprived rats had depleted glutathione stores (50%) and as a consequence were more susceptible to the oxidizing effects of cumene hydroperoxide. These results suggest that if glutathione plays a major role in the defence of the intestinal mucosa from ingested toxins then depletion of this defence during periods of food restriction could significantly increase the susceptibility of the individual to toxins present in the diet.
Prophylactic nutritional modification of the incidence of diabetes in autoimmune non-obese diabetic (NOD) mice
Authors: Hoorfar J. , Buschard K. , Dagnaes-Hansen F.
Published: June 2005

Experiments in rodent models of insulin-dependent diabetes mellitus (IDDM) suggest that destruction of pancreatic p cells can be both initiated and inhibited by certain environmental factors such as dietary constituents. We studied nutritional impact of certain protein sources of natural-ingredient, non-purified (NP) rodent diet on diabetes incidence and insulitis severity in the spontaneous diabetic, non-obese diabetic (NOD) mouse. Long-term ad lib. feeding of diets containing wheat flour (800 g/kg), and to a lesser extent soya-bean meal (400 g/kg), were associated with relatively high diabetes incidence (65 and 45% respectively), whereas a diet based on hydrolysed casein (HC; 200 g/kg) as the only source of protein significantly (compared with the wheat-flour diet) inhibited expression of diabetes (22 YO). Feeding a hypo-allergenic soya-bean-protein hydrolysate resulted in diabetes incidence and insulitis severity similar to that of the soya-bean-meal-fed group. This may indicate that protein hydrolysis per se may not be necessary for dietary modification of diabetes in the NOD mouse. The window of vulnerability to diabetogenic diets was found to be between weaning and about 70 d of age. In the diabetic mice insulitis was less frequent in the HC-fed group when compared with those fed NP (P = 0.04), soya- bean meal (P = 0.03), soya-bean-protein hydrolysate (P = 0.012) or wheat flour (P = 0.0002). In the non-diabetic mice the wheat-flour diet was associated with a high insulitis severity in comparison with the HC group (P = 0.004). Early avoidance of NP diet was associated with lower degree of insulitis in both diabetic (P = 0.00003) and non-diabetic mice (P =0.001) when compared with the mice fed on the HC diet later in life. These findings are contributing to further clarification of diabetes-promoting dietary constituents, which may have some nutritional implications for IDDM-susceptible children.
Measurements of 2H and 18O in body water: analytical considerations and physiological implications
Authors: Ritz P. , Johnson P. G. , Coward W. A.
Published: June 2005

Measurement of energy expenditure with doubly-labelled water and of body composition and breast milk output with 2H or 18O requires accurate and precise techniques for measuring isotopic enrichments. The possibility of an inaccuracy in measurements of 2H and 18O isotopic enrichment arising from the matrix in biological fluids was investigated (1) by simulating a dilution experiment in both water and urine samples and (2) by reconstituting urine samples, ranging from 10 to 60 g/kg in solid concentration, from freeze-dried urinary solids mixed with either natural abundance or doubly-labelled water. Current techniques involved in measuring 2H and 18O isotopic enrichments were used (reduction of the samples to H2 gas with either Zn or U, and CO2/H2O equilibration or direct measurement of mass 20:18 ratios on water vapour for 18O analysis). All four methods accurately measured serial dilutions in both urine and water. Dilution space calculated from isotopic enrichments, compared with the water content of urine (determined by freeze-drying and accounting for exchangeable isotopes) was overestimated by about 2.4 % by the Zn technique whereas other methods were accurate. The urinary solids content of a water solution was related to that inaccuracy. The use of the Zn technique with biological samples is likely to create biases in 2H distribution space. Examination of recent literature supports this view. Caution should therefore be used when physiological conclusions have to be made from the relative size of 2H and 18O distribution spaces.
Total energy expenditure and energy intake in the pre-school child: a comparison
Authors: Davies Peter S. W. , Coward W. A. , Gregory J. , White A. , Mills A.
Published: June 2005

In a cohort (n 81) of healthy children aged 1.5–4.5 years, measurements of energy intake and energy expenditure were compared. Energy intake was calculated following a 4 d weighed record completed by the mother or guardian of the child. Total energy expenditure was measured using the doubly-labelled water technique. Mean energy intake and expenditure in the cohort were 4773 kJ/d and 4928 kJ/d respectively. The mean relative bias between the techniques was 154 kJ/d. In the older children (3.5–4.5 years) the mean relative bias was only 37 kJ/d. At the population level the measurements of energy intake and energy expenditure were extremely close, and the study has provided sufficient confidence in weighed intake methodology for it to be used in a major nationwide study of dietary intake and nutritional status of children aged 1.5–4.5 years.
Energy metabolism in free-living, ‘large-eating’ and ‘small-eating’ women: studies using 2H218O
Authors: Clark Dallas , Tomas Frank , Withers Robert T. , Chandler Colin , Brinkman Menno , Phillips John , Berry Michael , Ballard F. John , Nestel Paul
Published: June 2005

The doubly-labelled water (2H218O) technique was used to assess the long-term rates of energy expenditure and, after accounting for any changes in body composition, the derived rates of energy intake in weight-stable ‘large-eating’ (n 6) and ‘small-eating’ (n 6) women. The self-reported energy intakes (approximately 11.2 v. 5.6 MJ/d) and energy expenditures (approximately 8.5 v. 12.4 MJ/d) for the ‘large-eating’ and ‘small-eating’ groups respectively, should not be sustainable without significant body-weight changes. 2H218O-assessed rates of energy expenditure for the ‘large-eaters’ (approximately 8.5 MJ/d) and ‘small-eaters’ (approximately 11.3 MJ/d) were in close agreement with the results obtained using 5 d, self-reported activity diaries but the derived rates of energy intake for the ‘large-’ (approximately 8.5 MJ/d) and ‘small-eaters’ (approximately 10.8 MJ/d) were markedly different from those obtained using self-reported, weighed food diaries. When two ‘small-eaters’ were supplied with their self-reported energy intakes (approximately 5 MJ/d) for up to 28 d both subjects lost about 0.75 kg body-weight/week. These results provide no support for the existence of ‘metabolically efficient’ women in the community.
Measuring the body composition of elderly subjects: a comparison of methods
Authors: Reilly J. J. , Murray L. A. , Wilson J. , Durnin J. V. G. A.
Published: June 2005

There is a paucity of data on differences between methods for the assessment of body composition in elderly subjects. Studies on younger adults suggest that such differences are of some practical significance at the individual level. In the present study the following methods of estimating percentage body fatness (BF%) were compared in healthy elderly men and women (mean age 70 (SD 6) years: densitometry; skinfold thickness; total body water; bioelectrical impedance (BIA) using an age-specific predictive equation and the manufacturers' equation; body mass index (BMI). Though BF% estimates from the various methods tended to be highly correlated with those from densitometry and with each other, differences between methods at the individual level were marked. In particular, the age-specific equations based on BMI and BIA systematically overestimated BF% relative to the other methods. Biases between BF% estimates derived from densitometry, skinfolds, BIA (manufacturers' equation) and total body water were less marked, indicating little evidence of systematic differences between these methods in elderly subjects. Individual differences between methods were slightly greater than those reported in some studies of younger adults, but this may be of little practical significance, and may be considered inevitable in view of variability between and within subjects in the extent to which the underlying assumptions of these two-component methods are met in elderly subjects.
The kinetics of nutrient incorporation into body tissues of gilthead seabream (Sparus aurata) females and the subsequent effects on egg composition and egg quality
Authors: Harel Moti , Tandler Amos , Kissil George W. , Applebaum Shalom W.
Published: June 2005

The interaction between essential dietary components and changes in tissue nutrient reserves, egg quality and egg composition, were studied from 60 d before and during the spawning ofSparus auratabroodstock. Fish were given isonitrogenous (550 g/kg dry weight) and isolipidic (100 g/kg dry weight) diets, based on protein and lipid extracts of squid meal. Diets differed in the levels ofn−6 (10–30 mg/g dry weight) andn−3 (0–10 mg/g dry weight) essential fatty acids. The effects of these diets on biochemical and fatty acid composition of body tissues, and the subsequent effects on egg composition and egg viability were measured. Dietary essential fatty acids were mostly incorporated into the liver, ovaries, digestive tract and associated adipose tissues. The lipid composition of these tissues reached an equilibrium with dietary lipid composition within 15 d of feeding on any given diet. Muscle and gill cartilage tissues did not show any significant changes in their biochemical and fatty acid composition, even after 60 d feeding. Egg viability decreased significantly within 10 d of feeding the broodstock with a diet deficient inn−3 highly unsaturated fatty acids (n−3 HUFA). The levels ofn−3 HUFA in both polar and neutral fractions of egg lipid were directly correlated with their levels in the broodstock diet. When the total amount of eggn−3 HUFA dropped below 17 mg/g dry weight, egg viability and larvae hatching rate decreased by 53% and 47 % respectively. These results suggest that the biochemical composition of organs involved inS. auratareproduction are highly sensitive to the nutritional value of the diet, which affects egg and larval quality rapidly.
The effect of dietary crude protein content on apparent and true ileal nitrogen and amino acid digestibilities
Authors: Donkoh A. , Moughan P. J.
Published: June 2005

The effect of dietary protein content (25, 60, 95, 130, 165 and 200 g crude protein (N × 6.25)/kg diet) on the apparent and true ileal digestibilities of N and amino acids in meat-and-bone meal given to the growing rat was investigated. Semi-synthetic diets in which meat-and-bone meal was the sole protein source were given to 180 g body-weight rats for 14 d. On the fourteenth day the rats were fed and then killed 4 h after the start of feeding and digesta were sampled from the terminal 200 mm ileum. Endogenous amino acid excretion was determined for eighteen rats given an enzymically hydrolysed casein (EHC)-based diet and with subsequent treatment of the digesta using ultrafiltration. The EHC-fed rats were killed 3 h after the start of feeding and digesta were collected from the terminal 200 mm ileum. True ileal digestibility values determined with reference to Cr as a marker were higher than the corresponding apparent estimates. Apparent digestibility values of N and amino acids increased significantly (P < 0.001) with increasing dietary protein level; however, dietary protein content had no significant (P > 0.05) effect on the true ileal digestibilities of N and amino acids. The mean apparent ileal digestibility of N in meat-and-bone meal ranged from 65.6 to 75.3%. The corresponding range for the true ileal digestibility of N was 76.9 to 78.2%. True ileal digestibility, unlike apparent digestibility, appears to be independent of dietary protein level and may allow feed ingredients to be compared accurately even if they are ingested in different quantities.
Casein and soya-bean protein have different effects on whole body protein turnover at the same nitrogen balance
Authors: Nielsen K. , Kondrup J. , Elsner P. , Juul A. , Jensen E. S.
Published: June 2005

The present study examined whether different proteins have different effects on whole-body protein turnover in adult rats. The rats were either starved, given a protein-free but energy-sufficient diet (1 MJ/kg body weight (BW) per d) or a diet containing intact casein, hydrolysed casein, or hydrolysed soya-bean protein at a level of 9.1 g/kg BW per d. The diets, which were isoenergetic with the same carbohydrate: fat ratio, were given as a continuous intragastric infusion for at least 4 d. During the last 19 h15N-glycine (a primed continuous infusion) was given intragastrically and15N was recovered from urinary ammonia and urea during isotope steady state for measurement of protein synthesis and protein degradation. Compared with starvation the protein-free diet decreased N excretion by 75%, probably by increasing the rate of reutilization of amino acids from endogenous proteins for protein synthesis. The protein diets produced a positive N balance which was independent of the protein source. Intact and hydrolysed casein increased protein synthesis 2.6- and 2.0-fold respectively, compared with the protein- free diet. Protein degradation increased 1.4- and 1.2-fold respectively. Hydrolysed soya-bean protein did not increase protein synthesis but decreased protein degradation by 35% compared with the protein-free diet. Compared with the hydrolysed soya-bean protein, intact casein resulted in 2.2- and 2.8-fold higher rates of protein synthesis and degradation respectively. These results are not easily explained by known sources of misinterpretation associated with the15N-glycine method. Hydrolysed casein and hydrolysed soya-bean protein produced similar concentrations of insulin-like growth factor-1, insulin, glucagon, and corticosterone. The difference in amino acid composition between the dietary proteins was reflected in plasma amino acid composition and this is suggested to be responsible for the different effect on protein turnover. Preliminary results from this study have previously been published in abstract form (Nielsenet al.1991).
Dietary modifications of the biliary bile acid glycine: taurine ratio and activity of hepatic bile acid-CoA:amino acidN-acyltransferase (EC2.3.1) in the rat
Authors: Ide T. , Kano S. , Murata M. , Yanagita T. , Sugano M.
Published: June 2005

Effects of dietary manipulations on the biliary bile acid glycine: taurine (G: T) ratio and the activity of hepatic bile acid-Co A: amino acidN-acyltransferase (EC2.3.1) in the post-mitochondrial fraction of liver homogenates were examined in the rat. The G:T ratio in rats fed on the diet containing 100 g pectin/kg (2.18) was markedly higher than that in the animals fed on the diet containing 100 g cellulose/kg (0.09). The diets containing either 10 g cholesterol/kg or 5 g sodium cholate/kg, especially the latter, also increased the G:T ratio (0.77 and 2.33 respectively) compared with a control diet free of these steroids (0.34). When the saturating concentrations of taurine (20 mM) and glycine (100 mM) were the substrates, dietary pectin relative to cellulose significantly increased the activity of both taurine- and glycine-dependent bile acid-CoA: amino acidN-acyltransferase, but neither dietary bile acid nor cholesterol influenced it. In spite of the marked difference in the G:T ratio among the rats given various types of experimental diet, the bile acid-CoA: amino acidN-acyltransferase reaction produced taurine- but little glycine-conjugated bile acid when both taurine and glycine coexisted at physiological concentration ranges in the assay media. Dietary manipulations modified the hepatic taurine concentrations and the changes were inversely correlated with those in the G: T ratio. However, hepatic concentration of taurine (1.67–4.82 μmol/g) in rats given various types of experimental diet was comparable with or even higher than the reported Michaelis constant (Km) value ofN-acyltransferase for this compound (0.8–2.5 mM). In contrast, glycine concentrations (1.81–2.58 μmol/g) were much lower than theKmvalue for this amino acid (35–40 mM) under various dietary conditions. Thus, neither the substrate specificity of the bile acid conjugation enzyme nor the alteration in the hepatic concentration of taurine or glycine accounted for the change in the G: T ratio in the present study.
Fasting plasma triacylglycerol concentrations predict adverse changes in lipoprotein metabolism after a normal meal
Authors: Potts Jennifer L. , Humphreys Sandy M. , Coppack Simon W. , Fisher Rachel M. , Gibbons Geoffrey F. , Fray Keith N.
Published: June 2005

The changes in lipoprotein metabolism which follow the ingestion of a large fat load have been well described. The hypothesis was tested that similar changes in lipoprotein metabolism would occur after a relatively normal meal. Plasma and lipoprotein triacylglycerol, cholesterol and apolipoprotein concentrations were determined in twenty subjects (ten female) given a mixed meal containing approximately one-third of the daily intake of major nutrients in the typical Western diet. Fasting plasma triacylglycerol concentrations (range 0.38–2.70 mm/l) and the postprandial rise in plasma triacylglycerol varied considerably between subjects and were significantly associated (P< 0.01). The rise in plasma triacylglycerol corresponded to marked increases in the triacylglycerol concentration of the triacylglycerol-rich lipoproteins (TRL; chylomicrons and very-low-density lipoproteins). TRL cholesterol also increased after the meal. An increase in high-density-lipoprotein (HDL)-triacylglycerol following the meal was accompanied by a decrease in HDL-cholesterol concentration, presumably due to the action of the cholesteryl-ester transfer protein. The increases in HDL-triacylglycerol and in TRL- cholesterol were correlated with the postprandial rise in triacylglycerol in the TRL (P< 0.01). We conclude that potentially adverse changes occur in both triacylglycerol-rich and high-density lipoproteins following a typical mixed meal, as they do after large fat loads. The changes are exaggerated in those subjects with greater fasting plasma triacylglycerol concentrations.
Thiamin intake, erythrocyte transketolase (EC2.2.1.1) activity and total erythrocyte thiamin in adolescents
Authors: Bailey Angela L. , Finglas P. M. , Wright A. J. A. , Southon Susan
Published: June 2005

The relationships between thiamin intake, erythrocyte transketolase (EC2.2.1.1) activity coefficient (ETK-AC) and total erythrocyte thiamin were investigated in a group of adolescents (13 to 14 years old; nineteen boys, thirty-five girls). Thiamin intakes were calculated from 7 d weighed records, using food composition tables, and compared with those obtained by direct analysis of duplicate diets. Average 7 d calculated thiamin intakes were significantly lower than analysed intakes for both sexes. On an individual basis, calculated intakes ranged from 30 to 143 % of corresponding analysed values. Analysed and calculated intakes were significantly correlated when expressed as mg/d; however, when expressed in terms of energy intake, the correlation was significant for males only. Thiamin intake appeared largely adequate when compared with current UK dietary recommendations (Department of Health, 1991), but the limitations of such comparisons are considered. The major food groups contributing to thiamin intake were examined and showed breakfast cereals to contribute more than 25% of dietary thiamin. A proportion of the subjects had ETK-AC values in ranges usually associated with marginal or severe thiamin deficiency. There was, however, no statistically significant relationship between erythrocyte thiamin and basal or stimulated transketolase activity, or between thiamin intake and either of the methods used to assess status. The need to re-evaluate indices of thiamin status is discussed.
The vitamin E nutritional status of rats fed on diets high in fish oil, linseed oil or sunflower seed oil
Authors: Farwer Sandra R. , Der Boer Bernardus C. J. , Haddeman Edward , Kivits Gerardus A. A. , Wiersma Antoon , Danse Berry H. J. C.
Published: June 2005

Twelve groups of eight rats and two control groups of sixteen rats were given semisynthetic diets with 40% energy as fat for a period of 76 d. All diets contained a minimum of 3% energy as linoleic acid and comparable basal levels of D-α- and D-γ-tocopherol. The diets varied in fat composition and in the content of DL-α-tocopheryl acetate. The diets high in polyunsaturated fatty acids (PUFA) were either rich in fish oil (FO; groups 1–4; 10% energy as fish oil PUFA), linseed oil (LN; groups 1–4; 10% energy as α-linolenic acid) or sunflower seed oil (SF; groups 1–4; 10 + 3% energy as linoleic acid). The control groups were given a diet high in monounsaturated fatty acids (MUFA; CO 1; 10 + 13% energy as oleic acid) or a diet with an ‘average’ linoleic acid content (CO 2; 8.5% energy as linoleic acid). Of each high PUFA diet three groups were supplemented with graded levels of DL-α-tocopheryl acetate. Steatitis, a sensitive histopathological indicator of vitamin E deficiency in animals fed on diets rich in fatty acids with three or more double bonds, was observed only in the adipose tissue of the FO groups, even in the group with the highest DL-α-tocopheryl acetate supplementation. Liver and serum α- tocopherol levels were found to be positively correlated and liver and serum γ-tocopherol levels negatively correlated with dietary DL-α-tocopheryl acetate. The groups on the FO diets had significantly reduced liver and serum tocopherol levels in comparison with the groups on the other high-PUFA diets. With the supplementation scheme used for the FO groups the liver α-tocopherol levels of both control groups were reached but the serum control levels were not.
Effect of ammonia treatment of wheat straw with or without supplementation of potato protein on intake, digestion and kinetics of comminution, rumen degradation and passage in steers
Authors: Oosting S. J. , Vlemmix P. J. M. , Van Bruchem J.
Published: June 2005

Untreated wheat straw (UWS) or ammoniated wheat straw without (AWS) or with (AWSP) a supplement of potato protein of a low rumen degradability was fed to three steers according to a 3 × 3 Latin square design. All rations were supplemented with sugar-beet pulp and minerals. Voluntary organic matter intake (OMI, g/kg0.75 per d) was 67.8, 76.0 and 80.1 for whole rations (51.1, 59.7 and 59.2 for straw) for UWS, AWS and AWSP respectively, which was significantly higher for AWS and AWSP than for UWS. Organic matter digestibility (OMD, g/kg) was 561, 596 and 625 for the respective rations UWS, AWS and AWSP, also significantly higher for AWS and AWSP than for UWS. The increased voluntary intake and digestion of ammoniated wheat-straw-based rations were associated with a significantly higher potentially degradable fraction (D) of neutral detergent fibre (NDF) in offered straw (556 and 661 g/kg for untreated and ammoniated wheat straw respectively) and in the rumen pool (469, 555 and 554 g/kg for UWS, AWS and AWSP respectively). Isolated small rumen particles (retained on sieves with a pore size < 1.25 and > 0.041 mm) had a significantly lower D of NDF (average 588 g/kg) than isolated large rumen particles (average 663 g/kg). Fractional rates of degradation of NDF did not differ significantly either between untreated and ammonia-treated wheat straw offered (2.9 and 2.6%/h respectively) or between rumen pools (1.8, 1.7 and 2.1 %/h for UWS, AWS and AWSP respectively). Rations based on ammoniated wheat straw had a significantly higher rumen NH3-N concentration than UWS. Although the rumen pool size of total contents differed significantly between treatments, those of dry and organic matter and of cell wall constituents were not significantly different. The proportion of rumen dry matter passing through a sieve with a pore size of 1.25 mm averaged 0.684 over rations (not significantly different between rations). Daily rumination (96 min) and eating (52 min) times/kg NDF ingested did not differ between rations. The rate of comminution of large particles estimated from the disappearance of indigestible NDF in large rumen particles from the rumen of animals without access to feed was 4.1, 6.3 and 7.1 %/h for UWS, AWS and AWSP respectively. These values were not significantly different. The fractional rate of passage estimated from the faecal excretion of Cr-NDF was 5.4, 6.1 and 6.3%/h for UWS, AWS and AWSP respectively (significantly higher for AWS and AWSP than for UWS) but the turnover rate of indigestible NDF did not differ between treatments.
Supplementation of a restricted maternal diet with protein or carbohydrate alone prevents a reduction in fetal muscle fibre number in the guinea-pig
Authors: Dwyer Catherine M. , Stickland Neil C.
Published: June 2005

A 60 % reduction in maternal feed intake is known to cause a reduction of approximately 20 % in biceps brachii fibre number in the guinea-pig fetus. This investigation was designed to isolate the dietary component responsible by reducing all dietary components to 60 % of the ad lib. level and supplementing the protein, carbohydrate or fat component to the level of the ad lib. intake. Fetal muscles were examined at 50 d gestation to determine numbers of primary and secondary fibres, and at term to determine total fibre number. Fetal and neonatal weights were reduced in all restricted groups (P < 0.05) when compared with ad lib. controls. At term this reduction was significantly less (P < 0.05) in the protein-supplemented group (20%) than in the 60 %-restricted and fat-supplemented groups (43%) and the carbohydrate-supplemented group (34%). Biceps brachii fibre numbers were reduced in the 60%-restricted and fat-supplemented groups by 14–16%, but fibre numbers were similar in control, protein-supplemented and carbohydrate-supplemented groups. Any reduction in fibre number was in the secondary fibre component of total fibre number. Therefore, biceps brachii fibre numbers were reduced only when maternal diets were deficient in both protein and carbohydrate.
The effect of heat on amino acids for growing pigs
Authors: Van Barneveld R. J. , Batterham E. S. , Norton B. W.
Published: June 2005

Two growth experiments were conducted to determine the effect of heat on the utilization of ileal-digestible lysine from field peas (Pisum sativum cultivar Dundale) fed to growing pigs. Five lysine-deficient diets (0.36 g ileal-digestible lysine/MJ digestible energy (DE)) were formulated using raw field peas, and field peas heated to either 110°, 135°, 150°, or 165° for 15 min respectively in a forced-air dehydrator. Additional diets were formulated with supplements of free lysine to verify that lysine was limiting in the diets containing the raw peas, and peas heated to 150° or 165°. The growth performance and retention of ileal-digestible lysine by pigs given the diets was determined over the 20–45 kg growth phase. Heat had a significant quadratic effect (P < 0.01) on growth rate, with responses declining from 543 g/d with pigs given the raw peas, to 407 g/d for those given the peas heated to 165°. Similarly, crude protein deposition declined in a quadratic manner (P < 0.001) from 76 to 36 g/d for pigs fed on raw peas and peas heated to 165° respectively. Retention of ileal-digestible lysine was 0.85 in the pigs given the raw field peas and declined in a quadratic manner (P < 0.001) with the application of heat to 0.48 in those pigs given the peas heated to 165°. Pigs fed on field peas heated to 165° had increased (P < 0.05) liver weights. The results indicate that heat applied to protein concentrates, even at mild temperatures, renders lysine in a form that is apparently absorbed but inefficiently utilized by the growing pig. Consequently, ileal digestibility values for lysine in heat-processed meals are unsuitable for diet formulations.
Effect of chitin and chitosan on nutrient digestibility and plasma lipid concentrations in broiler chickens
Authors: Razdan A. , Pettersson D.
Published: June 2005

Broiler chickens were fed on a control diet based on maize and maize starch or diets containing chitin, or 94, 82 or 76% deacetylated chitin (chitosans) with different viscosities (360, 590 and 620 m Pa.s respectively) at an inclusion level of 30 g/kg. Animals had free access to feed and water for the whole experimental period. On days 10 and 18 of the experiment chickens given the control and chitin-containing diets weighed more, had consumed more feed and had lower feed conversion ratios (g feed/g weight gain) than chitosan-fed birds. Feeding of chitosan-containing diets generally reduced total plasma cholesterol and high-density-lipoprotein (HDL)-cholesterol concentrations and gave an increased HDL:total cholesterol ratio in comparison with chickens given the control and chitin-containing diets. However, no significant reductions in plasma triacylglycerol concentrations resulting from feeding of the chitosan-containing diets were observed. The reduction in total cholesterol concentration and increased HDL: total cholesterol ratio were probably caused by enhanced reverse cholesterol transport in response to intestinal losses of dietary fats. The suggestion that dietary fat absorption was impeded by the chitosans was strengthened by the observation that ileal fat digestibility was reduced by 26% in comparison with control and chitin-fed animals. In a plasma triacylglycerol response study on day 21, feeding of 94 and 76%-chitosan-containing diets generally reduced postprandial triacylglycerol concentrations compared with chickens given the chitin-containing diet. Duodenal digestibilities of nutrients amongst chickens given the chitin-containing diet were generally lower than those of control and chitosan-fed birds indicating decreased intestinal transit time. The reduced caecal short-chain fatty acid concentrations of chickens given chitosan diets compared with the control diet illustrates the antimicrobial nature of chitosan. The fact that the three chitosan-containing diets affected the registered variables similarly indicated that the level of inclusion of chitosans in the diet exceeded the level at which the effect of the different viscosities could be significant.
The effects of pectin and wheat bran on the distribution of a meal in the gastrointestinal tract of the rat
Authors: Brown N. J. , Greenburgh A. , Tomlin J.
Published: June 2005

The effects of wheat bran and pectin on the gastrointestinal distribution of a radiolabelled, homogenized baked-bean meal were investigated in the rat. These fibres were chosen because of their very different physical characteristics; wheat bran is a coarse, particulate, mainly insoluble fibre whilst pectin is a soluble viscous polysaccharide. Sixty male rats were administered orally with control or test meals and five from each group were killed after 50, 100, 200 and 300 min. The gut was removed and the distribution of the meal established scintigraphically. Addition of the fibres altered the distribution of the meal with faster accumulation at the distal and caecal areas. Wheat bran delayed gastric emptying whilst pectin promoted gastric emptying and had a pronounced effect on increasing the distal accumulation of the meal. These alterations in the distribution of a homogenized baked bean meal show that dietary fibres with different physical characteristics may alter gastrointestinal motility in different ways and these differences may have implications for meal absorption and clinical treatments of gastrointestinal disorders.
Effects of wheat-flour and oat mill fractions on jejunal flow, starch degradation and absorption of glucose over an isolated loop of jejunum in pigs
Authors: Johansen Helle N. , Bach Knudsen K. E.
Published: June 2005

The effect of cereal-based diets varying in dietary fibre (DF) on gastric emptying and glucose absorption over an isolated loop of jejunum was studied in four pigs fitted with two sets of re-entrant cannulas. The pigs were fed on either a wheat-flour diet or three diets based on oat flour (endosperm), rolled oats or oat bran containing different amounts of soluble DF. Mean transit time (MTT) of liquid estimated from the output from the first jejunal cannula was significantly higher with the two diets having the highest DF content, but MTT of dry matter (DM), starch, xylose and neutral non-starch polysaccharides (nNSP) was not correlated directly to the DF content of the diet. DF had a stimulatory effect on secretion of gastrointestinal juices, but the effect was not linearly correlated with the DF content of the diet. Starch was significantly degraded in digesta collected within 30 min after feeding with malto-oligosaccharides accounting for 140–147 g/kg total starch. The degradation was more extensive with higher DF and lower starch content of the diet. However, taking into account the differences in jejunal flow, the amount of malto-oligosaccharides available for absorption in the first 0.5 h decreased with higher levels of DF in the oat-based diets. The absorption of glucose from the isolated loop was 18–34 g/m intestine over an 8 h period with no significant differences between diets. This corresponded to a non-significant decrease in recovery of starch from 0.91 to 0.82 with increasing levels of DF and decreasing levels of starch in the diet. This suggests that the capacity for absorption of large doses of starch entering the proximal small intestine after ingestion of a carbohydrate-rich cereal-based diet has a major influence on the absorption at this site. Consequently any effect of DF on glucose absorption may be exerted either through the rate of gastric emptying or by impaired rate of absorption more distal in the small intestine and not by displacement of the site for starch absorption.