Bran Diet Research Articles

Antimutagenic effects of wheat bran diet through modification of xenobiotic metabolising enzymes

Diets containing wheat bran (WB) protect against cancers of the colon or breast in rats, and may be beneficial in humans. In a previous study of rats treated with the carcinogen 2-amino-3-methylimidazo[4,5- f]quinoline (IQ), inclusion of 10% wheat bran in the diet led to an apparent reduction in IQ metabolites but not of intact IQ in plasma. In the present study, male Wistar rats were fed diets containing 0, 10 or 20% wheat bran, and effects on xenobiotic metabolising enzymes compared. Wheat bran-supplementation showed differential effects on phase I enzymes, significantly increasing the activity of hepatic cytochrome P450 isozyme CYP3A2, but slightly reducing the activity of CYP1A1/2. The activities of both hepatic phase II detoxification enzymes glutathione- S-transferase and glucuronosyl transferase were also reduced. Western blotting revealed similar effects on expression of the proteins. Interestingly, the expression of xenobiotic metabolising enzymes (XME) in the colon appeared to be modulated independently of hepatic XME. Although the wheat bran-supplemented diet still led to an increased expression of CYP3A, it now slightly increased CYP1A in the colon. However, 20% wheat bran significantly increased the expression of both glutathione transferase isozymes, GST A1 & A2, in the colon. Natures Gold™ (NG) is a commercial wheat bran derivative which is lower than wheat bran in dietary fibre, but enriched in vitamins, minerals and various phytochemicals. Dietary supplementation with 20% Natures Gold™ led to similar trends as seen in wheat bran-fed rats, but more potent effects in both hepatic and colonic enzymes. The significance of these changes for activation of carcinogens to mutagenic metabolites was investigated using the Salmonella/mammalian microsome mutagenicity test. The activation of IQ and benzo[ a]pyrene, but not cyclophosphamide, to a mutagen by hepatic S9 from wheat bran-fed or Natures Gold™-fed rats was significantly reduced compared with S9 from animals on a diet lacking wheat bran. We suggest that modulation of xenobiotic metabolising enzymes may be an important component of cancer protection by wheat bran, and this effect may relate to micronutrients or cancer-protective non-nutrient phytochemicals rather more than to dietary fibre.

Dietary Phytic Acid and Wheat Bran Enhance Mucosal Phytase Activity in Rat Small Intestine

The aim of this work was to investigate the influence of dietary phytic acid (PA) on intestinal phytase activity in growing rats by in vitro determination of phytase activity in the three segments of the small intestine (duodenum, jejunum and ileum), and by in vivo intestinal perfusion of a solution rich in PA (diluted soymilk). Using the in vitro method, duodenal and jejunal activities were enhanced significantly by adaptation to purified PA (+44 and +145% respectively, compared with control rats). For the rats adapted to the wheat bran (WB) diet, the induction of intestinal phytase by the substrate compared with the control values (P < 0.001) was observed only in ileum. Using soymilk in perfusions, rats consuming PA or WB diets hydrolyzed more phytate (P < 0.001 and P < 0.05, respectively) than controls. Further, Mg absorption from diluted soymilk was not affected by food adaptation, whereas Ca absorption was greater in the PA and WB groups (P < 0.001 and P < 0.05, respectively) than in the control group. Thus, intake of pure PA by rats enhances phytase in the upper parts of the small intestine (duodenum and jejunum), whereas the WB diet activates ileal phytase. Furthermore, the induction of phytase activity is greater in magnitude in rats fed synthetic PA than that observed in rats fed the WB diet. The enhancement of phytase improves intestinal Ca absorption, thus showing the capacity of the small intestine to adapt to diets rich in PA and poor in Ca.

A High Oat-Bran Intake Does Not Impair Zinc Absorption in Humans When Added to a Low-Fiber Animal Protein-Based Diet

Oat bran has a high phytate content and a low or inactivated phytase activity. A high intake of oat bran could therefore result in an impaired absorption of trace elements. The effect of a mean daily intake of 142 g of oat bran (102 g/10 MJ) on absorption of zinc was evaluated by the use of stable isotopes and fecal monitoring in 12 healthy subjects (6 males and 6 females). Each subject participated in two separate diet periods each of 21 d with identical low-fiber diets and with oat bran added in one of the periods. The oat bran was incorporated into bread and served at three daily main meals. The intake of zinc and phytate per 10 MJ was 138 micromol (9.0 mg) and 0.5 mmol, respectively, in the low-fiber period and 225 micromol (14.7 mg) and 4.0 mmol, respectively, in the oat bran period. Stable isotopes of zinc ((70)Zn) were added to the diets at d 7 of each period. The fractional absorptions (means +/- SD) of zinc from the low-fiber and oat bran diets were 0.48 +/- 0.11 and 0.40 +/- 0.15 (P = 0.07), respectively. The higher zinc content in the oat bran period resulted in a greater amount of zinc absorbed (64 +/- 19 micromol and 99 +/- 51 micromol, respectively, P = 0.009). Balance data suggest that the higher absorbed amount of zinc resulted in correspondingly higher intestinal endogenous excretion of zinc. In conclusion, the absorption of zinc was high and not affected by addition of oat bran.

Resistant starch improves mineral assimilation in rats adapted to a wheat bran diet

The effects of a natural source of phytic acid (PA) such as wheat bran (WB), in the presence or in the absence of resistant starch (RS) on the assimilation of minerals (Ca, Mg, P) and trace elements (Fe, Mn, Zn, Cu) were investigated in rats adapted to semipurified diets. The diets provided either 73g/100 g digestible wheat starch (DS) alone, or 53 g/100 g DS plus 20 g/100 g raw potato starch (RS) and either 0 or 20 g/100 g WB. Mineral content of all diets was adjusted before the beginning of the experiment. RS diets resulted in enlargements of the cecum together with an accumulation of short-chain fatty acids. As a result of the hypertrophy of the cecal wall, acidification of luminal pH and an elevated concentration of soluble minerals, the cecal absorption of Ca, Mg, and P was 3–5-fold higher in the RS groups than in the DS groups. Mineral apparent retention was significantly enhanced by RS ingestion (Ca, +39%; P, +30%; Mg, +32%; Zn, +47%; Fe, +27%; Mn, +5% and Cu, +37%). WB ingestion altered significantly P solubility and its cecal absorption. Thus, WB exerted a significant effect on P and trace elements balances (P, −29%; Zn, −60%; Fe, −26%; Mn, −22% and Cu, −47%). Nevertheless, with WB diets, the disappearance of phytic acid was 2-fold higher in rats fed the RS than those fed the DS. Thus, the addition of RS into WB diet allows a greater mineral absorption by increasing the organic acids production and the breakdown of PA in the large intestine.

The effects of Gliricidia sepium and maize bran as supplementary feed to Rhodes grass hay on intake, digestion and liveweight of dairy goats

Sixteen crossbred (Toggenburg x Saanen) dairy goat kids were used to evaluate the effects of gliricidia and maize bran supplementation to hay on dry matter intake and diet digestion. Rhodes grass ( Chloris gayana) hay basal diet was offered ad libitum alone or supplemented with 120 g/day of gliricidia meal, gliricidia meal plus maize bran (1:1) or maize bran. Total DMI was significantly lower ( P<0.05) in control group and increased with supplementation while the intake of the basal hay diet was not significantly changed. The total DMI and the hay intake were 474, 604, 565, 545 (s.e. 21.5) g/day) and 474, 504, 455, 437 (s.e. 21.7) g/day DM for the control, gliricidia, gliricidia plus bran and bran supplemented groups respectively. The live weight gains were highest ( P<0.05) in goats supplemented with a mixture of gliricidia and maize bran diet (69 g/day) and lowest for the control (26 g/day). Supplementation increased the digestibility dietary DM and N, and reduced that of NDF. It was concluded that gliricidia forage is better utilized when fed with an energy source such as maize bran.

Influence of foliage from different accessions of the sub-tropical leguminous tree, Sesbania sesban, on ruminal protozoa in Ethiopian and Scottish sheep

Nine different accessions of Sesbania sesban were examined for their toxicity to ciliate protozoa from sheep receiving a mixed grass hay–barley/fishmeal concentrate in Aberdeen, Scotland. Several accessions were much more toxic than those (ILRI 10865, ILRI 15036) identified and tested in a previous study. Two highly toxic accessions and one less toxic accession were compared with ILRI 15036 in a feeding trial in Debre Zeit, Ethiopia with sheep receiving a sululta hay–wheat bran diet. No suppression of protozoal numbers occurred in response to S. sesban supplementation (200 g/day). When rumen fluid removed from sheep on the supplemented diet was tested in vitro, protozoal activity appeared to be inhibited less by S. sesban in the mixed population than in either washed protozoa from the same rumen fluid or than had occurred in Scottish sheep. It was concluded that dietary, microbial or animal factors in the Ethiopian sheep had caused the destruction of the anti-protozoal material present in even the most potent accessions of S. sesban.

Effect of Extrusion on Hypocholesterolemic Properties of Rice, Oat, Corn, and Wheat Bran Diets in Hamsters

ABSTRACTBrans from rice, oats, corn, and wheat were cooked in a twin‐screw extruder at either high or low energy input, and their cholesterol‐lowering effects were compared with those of unprocessed brans when fed to four‐week‐old male golden Syrian hamsters (n = 10 per treatment) for three weeks. Peanut oil was added to oat, corn, and wheat bran during the extrusion process to match the oil content of rice bran. Diets contained 10% total dietary fiber, 10.3% fat, 3% nitrogen, and 0.3% cholesterol. Plasma and liver cholesterol and total liver lipids were significantly lower with low‐energy extruded wheat bran compared with unprocessed wheat bran. Extrusion did not alter the hypocholesterolemic effects of rice, oat, or corn brans. Plasma and liver cholesterol levels with corn bran were similar to those with oat bran. Relative cholesterol‐lowering effects of the brans, determined with pooled (extruded and unextruded) bran data, were rice bran &gt; oat bran &gt; corn bran &gt; wheat bran. Rice bran diets resulted in significantly lower levels of total plasma cholesterol and very low density lipoprotein cholesterol compared with all other brans. Total liver cholesterol and liver cholesterol concentrations (mg/g) were significantly lower with high‐energy extruded rice bran compared with the cellulose control group. Plasma cholesterol and total liver cholesterol values with low‐energy extruded wheat bran were similar to those with rice bran (unextruded or extruded) diets. Lowered cholesterol with rice bran diets may result in part from greater lipid and sterol excretion with these diets. Results with low‐energy extruded wheat bran suggest that this type of processing may improve the potential for lowering cholesterol with wheat bran products.

Effect of fibre-rich diets on the backfat skatole content of entire male pigs

The objective was to determine the effect of feeding diets differing in fibre content and source on backfat skatole content and boar taint score of entire male pigs. Sixty entire male pigs (Piétrain×Seghers hybrid cross) were assigned to four dietary treatments and fed ad libitum, in two phases (grower and fattening), one of the following diets: control, one with 15% sugar beet pulp, one with 30% wheat bran and one with 15% soybean hulls. The diets were isocaloric and isonitrogeneous, but differed in crude fibre content and fibre source. Mean crude fibre contents were 5.2, 7.7, 6.2 and 9.9%, respectively. Animal performance, carcass quality, backfat skatole and indole contents and boar taint scores were not influenced by diet. However, the wheat bran diet group gave a numerically ( P=0.219) higher backfat skatole content than the sugar beet pulp diet group (126±182 vs 37±54 ng/g fat; mean±S.D.). Under the experimental conditions, there was no higher risk for skatole formation or boar taint occurrence by feeding fibre-rich diets to entire male pigs, compared with a conventional diet.

Wheat Bran Diet Reduces Tumor Incidence in a Rat Model of Colon Cancer Independent of Effects on Distal Luminal Butyrate Concentrations ,

To investigate the effects of dietary fibers in colonic luminal physiology and their role in the prevention of colon cancer, a study was conducted using two diet groups and two treatment groups in a 2 × 2 factorial design. The two diets differed only in the type of dietary fiber, wheat bran and oat bran, and the two treatments were injection with the colon-specific carcinogen azoxymethane, or saline, as a control. There were 34 rats in the carcinogen-injected groups and 11 saline-injected rats per diet group. The goal of the study was to determine if a moderate consumption (6 g/100 g diet) of wheat bran or oat bran would alter the development of colonic tumors in this rat model of colon cancer, and if the differences in tumor incidence were correlated to luminal butyrate concentrations, luminal pH or fecal bulk. Short-chain fatty acid concentrations (SCFA) were measured in feces during the first half of the study (the promotion phase of tumor development) and again at the end of the study. Rats consuming oat bran had greater body weights (P< 0.002), produced much larger concentrations of all SCFA, including butyrate, in both the proximal and distal colon (P< 0.0001), had more acidic luminal pH values (P< 0.0001), but also had significantly more development of colon tumors (P< 0.03). Alternatively, rats consuming wheat bran produced more typical molar ratios of the SCFA (65:10:20), had a relatively greater concentration of butyrate than propionate, and produced a larger volume (P< 0.05) and more bulky stool than the rats fed oat bran. The results of this study support other evidence that an acidic luminal pH is not protective in and of itself, and that diets containing wheat bran are protective against colon cancer development. In addition, these data show that large luminal butyrate concentrations in the distal colon alone, as were present in the rats consuming oat bran diets, are not protective of tumor development.

Effects of enzyme supplementation and irradiation of rice bran on the performance of growing Leghorn and broiler chickens

Three experiments investigated the effects of different concentrations of a crude enzyme preparation (RM-1) and rice bran from two sources (China and Malaysia) on the performance of growing Leghorn and broiler chicks when added to a wheat or a corn soya-bean meal basal diet. In the first experiment rice bran from Malaysia was also irradiated. In this experiment enzyme supplementation of the wheat-basal diet containing 400 g kg −1 Malaysian rice bran improved ( P < 0.05) weight gains up to 9.6% and feed to gain ratio up to 5.4% while irradiation of rice bran at moderate (10 kGy) and high 50 (kGy) doses had no effect ( P > 0.05) on these parameters. Chinese rice bran in contrast to Malaysian rice bran did not respond to enzyme treatment ( P > 0.05). Similar improvements were obtained in the second experiment with RM-1 addition to the corn basal diet containing 250 and 500 g kg −1 Malaysian rice bran, but not when added to the corn diet without rice bran. In addition, rice bran did not have any deleterious effects ( P < 0.05) on growth and feed conversion efficiency of Leghorn chicks when incorporated into diets without enzyme supplementation. In contrast to the results with Leghorn chicks, the performance of broiler chicks was depressed ( P > 0.05) when 250 and 500 g kg −1 Malaysian rice bran was added to the diet. Chicks fed the diet containing 500 g kg −1 rice bran compared to those fed the control diet had decreased body weight gains (17%) and increased feed to gain ratios (11%), relative weights of the gastrointestinal tract (40%), and incidence of vent pasting (from 0 to 67%). Enzyme addition (10 mg kg −1) to the 500 g kg −1 rice bran diet improved ( P < 0.05) the feed to gain ratio (4%), and reduced the size of the gastrointestinal tract (7%) and the incidence of vent pasting (from 67 to 33%). These studies indicate that high concentrations (400–500 g kg −1) of rice bran can be added to the diet of Leghorn chicks, at least over a relatively short period of time, without a deleterious effect on performance while as low as 250 g kg −1 rice bran in the diet can depress broiler chick performance. The crude enzyme when added to diets containing rice bran produced equivocal results in chicks as it improved performance with one rice bran but not the other.

Dietary Guar Gum Improves Insulin Sensitivity in Streptozotocin-Induced Diabetic Rats ,

Although dietary recommendations for diabetics stress the need for increased carbohydrate and dietary fiber, the effectiveness of dietary fiber in improving insulin sensitivity remains controversial. The aim of this study was to compare the effects of a soluble fiber (guar gum) and an insoluble fiber (wheat bran) on insulin sensitivity in streptozotocin-induced (STZ) diabetic rats. Consequently, the rats were divided into two groups and one half were rendered diabetic with streptozotocin. The STZ diabetic and nondiabetic rats were further randomized and fed a diet containing dietary fiber (7 g/100 g diet) from either guar gum or wheat bran. The hyperinsulinemic clamp technique, combined with infusion of the glucose analog, 2-deoxyglucose (2DG), was utilized to examine insulin sensitivity. Bran-fed STZ diabetic rats were significantly (P < 0.001) hyperglycemic, which was ameliorated by guar gum. Insulin-mediated glucose disposal was increased by the guar diet compared with the bran diet in both the STZ diabetic rats [17.7 ± 2.2 vs. 11.8 ± 2.4 mL/(kg⋅min), P < 0.05] and the nondiabetic rats [20.5 ± 2.8 vs. 15.5 ± 1.5 mL/(kg⋅min), P < 0.05]. The accumulation of 2DG in peripheral muscles reflected the changes in insulin sensitivity with a trend for increased 2DG uptake in the majority of analyzed tissues in rats fed the guar diet, both nondiabetic and STZ diabetic, compared with the bran-fed rats. Accompanying these alterations in insulin sensitivity, guar gum suppressed food intake in the hyperphagic diabetic rats by 20% (P < 0.001). The present results demonstrate the effectiveness of guar gum in improving insulin sensitivity in STZ diabetic rats and suggest that reduced food intake may be an important mechanism of action of guar in hyperphagic diabetic rats.

Effect of high-amylose starch and oat bran on metabolic variables and bowel function in subjects with hypertriglyceridemia

We compared the effects of a diet in which approximately 25% of the carbohydrate was replaced by high-amylose starch with those of a similar diet high in oat bran or low-amylose starch in 23 hypertriglyceridemic subjects who were overweight mostly because of abdominal adiposity. Each diet was consumed for 4 wk in random order and in a crossover fashion. Overall, the diets were high in carbohydrate (> 55% of energy) and low in fat (< 30% of energy); the amount of resistant starch in the foods containing high-amylose starch was 17 g in women and 25 g in men. The metabolic effects of specific starches on plasma lipids, fasting and postprandial glucose and insulin profiles, and bowel function were assessed at the end of each intervention. Plasma triacylglycerols (triglycerides) were significantly lower after the oat bran diet than after the other two diets (P < 0.02). No other effects on fasting plasma lipids, glucose, or insulin were noted. However, when the high-amylose starch comprised 33% of the carbohydrate content in a test meal, there was a significant but biologically small reduction in the overall postprandial plasma insulin concentration by 17% relative to the low-amylose diet (P < 0.01). Both the oat bran and the high-amylose diet resulted in an increased frequency of bowel actions and lower fecal pH (P < 0.02) relative to the low-amylose diet. However, unlike the oat bran diet, the high-amylose diet increased short-chain fatty acid concentrations in fecal water by 32% (P < 0.001).

The catalytic effect of supplementation of protein meals on utilization of rice straw-poultry droppings-rice bran diet in buffaloes

Four graded Murrah ( Bubalus bubalis) bull calves (198.5 ± 3.0 kg) fitted with permanent rumen cannulae were used in a 4 × 4 latin square design to study the effect of supplementation of protein meals viz., groundnut cake (D-2), soyabean meal (D-3) or fish meal (D-4) at 100 g each to caged poultry droppings (CPD)-molasses-deoiled rice bran (DORB)-mineral (1810 g) mixture (D-1) and ad lib rice straw on in sacco rumen degradability of rice straw, voluntary feed intake, nutrient utilization and rumen fermentation pattern. Rumen degradation characteristics of dry matter (DM) and neutral detergent fibre (NDF) of rice straw (RS) and DM and crude protein (CP) of protein meals were described by fitting the in sacco data to the exponential equation p = a + b(1 − e − ct ). Rumen environment created by groundnut cake (GNC), soyabean meal (SBM) and fish meal (FM) supplementation increased ( P < 0.10) the rate of DM degradability ( c) of straw by 23.4%, 27.6% and 15.8%, respectively. Effective protein degradability of protein meals revealed that GNC protein was highly rumen degradable (93.2%) while FM protein was less degradable (49.2%) with SBM protein being intermediate (82.1%). Rates of protein degradability of GNC, SBM and FM were 0.1927, 0.2399 and 0.0720, respectively. Protein meal supplementation non-significantly increased rice straw and total DM intake (DMI) and significantly increased the DMI as a percentage of body weight ( P < 0.05) and per kilogram of metabolic body size ( P < 0.10). Voluntary DMI of buffaloes per kilogram W 0.75 was 81.9, 88.9, 89.6 and 91.0 g for D-1, D-2, D-3 and D-4, respectively. The apparent digestibilities of DM, OM, CP, NDF, acid detergent fibre (ADF) and cellulose were increased ( P < 0.01) due to supplementation of protein meal. It further increased the consumption of digestible crude protein (DCP) ( P < 0.01), metabolizable energy (ME) and DOM ( P < 0.05) and N retention ( P < 0.01) of buffaloes kept on RS diet. Animals fed FM diet had lower urinary N excretion and higher ( P < 0.01) N retention. Rumen NH 3-N concentration was significantly lower ( P < 0.01) in animals fed D-4 while animals fed D-3 or D-4 had significantly higher ( P < 0.01) total volatile fatty acid (TVFA) concentration. It is concluded that supplementation of RS-CPD based diet with various protein meals improved the performance of buffaloes with FM protein being superior in comparison with protein from GNC or SBM.

Endoscopic evaluation of the preventive effect of wheat bran against 1,2-dimethylhydrazine induced large bowel carcinogenesis in rats

We evaluated the preventive effects of wheat bran (40%, weight percent of diet) on the development of large bowel carcinoma induced by weekly intraperitoneal administration of 25 mg/kg (body weight) of 1,2-dimethylhydrazine over 19 weeks in the rat. Feces number and volume per pellet in wheat bran diet group were significantly greater than those in basal diet group, and the induction rates of tumor in the wheat bran diet group was found to be significantly lower than that in the basal diet group. These results suggested that wheat bran was effective in inhibiting large bowel carcinogenesis, and that the increased fecal weight and volume from wheat bran may be involved in such an inhibitory effect.

Effects of different processing procedures for rice bran on dietary nutrient digestion in each segment of the digestive tract of steers

Effects of feeding raw, heated and defatted rice brans (RR, HR and DR, respectively) and wheat bran (WB) on in situ rumen dry matter disappearance, the site and extent of digestion of dietary nutrients, and microbial synthesis in the rumen were investigated. Four Holstein steers fitted with ruminal, duodenal and ileal cannulas were used in a 4 × 4 Latin square design. Four diets consisting of 34–38% bran, 40% chopped Italian ryegrass hay and other supplements were formulated to contain 14% crude protein. All diets were fed at the same level of digestible energy intake (1.8 times maintenance requirement). Dry matter disappearance in situ was less for DR than for RR during the 24 h of incubation, but was higher afterwards. Disappearance of dry matter for HR was lower than for RR during the whole incubation period. Real intake of digestible energy was lower for RR and HR diets than for DR and WB diets due to lower than expected digestibility of fiber in the rumen and of fat in the small intestine. The proportion of nonstructural carbohydrates digested in the large intestine and total tract digestibility was higher for the rice bran diets than for the WB diet. Ruminal digestibility of starch was over 90%, but that of nonstructural and nonstarch polysaccharides was less than 40% for all diets. Nitrogen digestibility in the small intestine did not differ among diets, but was highest in the rumen and the total digestive tract for the WB diet. Microbial flow to the duodenum and microbial efficiency did not differ among diets. Raw and heated rice bran diets resulted in a higher proportion of propionate in ruminal fluid than did DR and WB diets. It is concluded that digestion of fiber and energy intake for high rice bran diets is increased by defatting the rice bran, but not by heat processing.

Effects of level of calcium or fiber type on digestibility of a tallow-supplemented diet by mice

Female CD1 weanling mice (16 g) were used to study effects of calcium and fiber level on growth and digestibility. Mice were limit fed a basal AIN purified diet with 14% tallow added (4.4 kcal/day) with calcium at either 0.6, 1.0, 1.5, 2.0, or 2.5% of diet dry matter. In addition, 10% (0.22 g/day) total dietary fiber was added to the 0.6% calcium diet from either cellufil, rice bran, wheat bran, or beet pulp. Growth rates, digestibilities, energy retention, and body composition were measured during the 28 day trial. Added calcium linearly (P<0.01) depressed digestibility of dry matter (83 versus 90%), digestibility of energy (87 versus 91%), and calculated Atwater values, while it increased fecal excretion of soap (P<0.01) and fat (P<0.10). For every 1% increase in dietary calcium, metabolizable energy decreased by 2%. Added fiber also increased (P<0.06) fecal fat and soap excretion and depressed dry matter and energy digestibility (P<0.01). Of the 4 tested fibers, mice fed the rice bran diet had the lowest (P<.05) digestibilities of dry matter, energy and fat. By depressing tallow digestibility and increasing fecal fat excretion, caloric value can be altered markedly by adding either calcium or fiber to a diet rich in fat.

Developmental Thresholds and Degree-Day Accumulations of Indianmeal Moth (Lepidoptera: Pyralidae) on Dried Fruits and Nuts

Degree-days for egg to adult development were determined for a laboratory and a wild-type isolate of the Indianmeal moth, Plodia intcrpunctella (Hubner), reared on wheat bran diet, almonds, pistachios, walnuts, raisins, and prunes. To avoid problems with temperature-induced diapause and effects of diet, eggs and pupae were used to estimate developmental thresholds used in degree-day determinations. Lower developmental thresholds for eggs (14.8) and pupae (13.8) of both isolates were identical. A threshold of 14 was used for degree-day determinations for both isolates. Egg hatch on all diets was lower for the wild-type isolate, but postembryonic survival of the wild-type isolate was similar to the laboratory isolate. Survival was <12% on dried fruits, 76.5-91.7% on nuts, and 9.5.3-97.3% on wheat bran. Degree-days for the laboratory isolate for each diet was lower than those for the wild-type isolate. Degree-days for each isolate was lowest when reared on wheat bran and highest when reared on dried fruits. The determination of developmental thresholds for eggs and pupae allows the use of a single lower threshold for all models, although different degree-days will be necessary for each commodity.

Effects of different nitrogen sources on productive parameters in Angora goats

Effects of various protein sources on yield and quality of mohair production were studied in Angora does. Soybean meal (SBM), sunflower meal (SFM), cotton seed meal (CSM), and poultry manure (PM) were included in experimental diets as test proteins. Angora does (n = 120) were allocated to four treatments for 1 yr receiving a basal diet of grass hay, bran, barley, minerals and vitamin mix plus SBM, SFM, CSM or PM. Fifty Angora does in the second experiment received graded levels of SFM and PM with 0, 3 and 6% CP to the basal diet. Mohair yield and quality were determined after 6 and 11 months. There were no significant differences in mohair yield and quality among protein sources, indicating that PM can be used as a cheap nitrogen alternative in Angora goat feeding. Inclusion of graded levels of SFM and PM tended to increase mohair quality in terms of increased staple length, breaking strength and decrease in medullated fiber. As a conclusion, adjustment in supplemental feed formulation can be made to economize on supplemental protein sources without affecting the production of mohair from Angora does.

Effect of soluble dietary fibre on the viscosity of gastrointestinal contents and the acute glycaemic response in the rat

The postprandial glycaemic response following a meal is reduced with the addition of soluble dietary fibre. The reductions in the glycaemia are thought to be due largely to increased viscosity of the gastrointestinal (GI) contents retarding digestion and absorption. The aims of the present study were to determine the effect that the GI tract has on the viscosity of meals containing different soluble fibres and to determine whether the glycaemic response of a meal (containing the soluble fibre) was predicted by the viscosity of the digesta in the small intestine. High carbohydrate diets containing 70 g soluble fibre guar gum, xanthan gum or methylcellulose)/kg or 70 g insoluble fibre (wheat bran)/kg were diluted in water to a final fibre concentration of 18 g/kg. Following dilution the wheat bran diet had no measurable viscosity, while the viscosities of the soluble fibre diets were elevated. When the diets were fed to male Sprague-Dawley rats for 2 weeks the viscosities of the stomach and small intestinal digesta were not predicted by the viscosity of the diets measured before ingestion. The action of the GI tract on the viscosity of the soluble fibres was investigated in vitro by dilution of the diets with acidic and neutralizing solutions, mimicking gastric and duodenal secretions. Dilution of diets with either acidic and neutralizing solutions or saline control significantly lowered the viscosity of all diets, while alterations in the pH of the diets had little impact on the resultant viscosity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of dietary fibre mixtures on glucose and lipid metabolism and on mineral absorption in the rat.

Four diets containing different mixtures of dietary fibre (DF) were tested in the rat to verify the effects of fibre source and fibre level on plasma glucose, insulin and lipids and on apparent intestinal absorption of minerals. Diets Puri5 and Puri 10 contained 5 and 10% of total DF from pectin and cellulose. Diets Bran 5 and Bran 10 supplied 5 and 10% DF from oat bran and wheat bran. A fifth diet with 5% cellulose was used as a control. Ten rats were fed each diet for 4 weeks. On days 3, 17 and 28, feces were collected and analyzed for Fe, Zn, Ca and Mg. On day 29, blood samples were collected in portal vein and abdominal aorta in fasted and fed rats from each group. All diets had similar effects on plasma insulin and triglycerides. Compared to Bran diets, Puri diets induced higher portal glucose (p < 0.01) and lower plasma cholesterol (p < 0.03) in fed rats. The apparent absorption of Fe, Zn and Mg was higher (p < 0.05) in rats fed Puri diets than in those fed Bran diets. For Ca, the difference was significant only on day 3. In this study, only the apparent absorption of Fe was affected (p < 0.01) by fibre level (5 > 10%). This indicates that in fibre mixtures, the source rather than the amount of fibre generally affects absorptive and metabolic parameters.