Dietary corn oil and guar gum stimulate intestinal crypt cell proliferation in rats by independent but potentially synergistic mechanisms

Antioxidant extract of black rice prevents renal dysfunction and renal fibrosis caused by ethanol-induced toxicity

This study was conducted to evaluate the protective role of extracted natural antioxidants from black rice and their effect on kidney failure and renal cirrhosis caused by ethanol-induced toxicity. Antioxidant activity in terms of total phenol content, flavonoid compounds and anthocyanin, as well as antioxidant capacity, was determined in an extract of black rice. The findings noted that the black rice extract contained high amounts of antioxidant activity and capacity. Total phenolic compounds from black rice extract were fractionated using HPLC and the results showed that ferulic, sinapic, ascorbic, salicylic and coumaric acids were the highest in the extract. Biological experiments were performed on male albino adult rats (40 animals, 10 rats for each group), divided into four groups. After five weeks, kidney functions and protein fractions were assessed. In addition, superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) enzyme activities were determined in all groups. The results found that kidney function, total protein, albumin and globulin were affected by renal dysfunction and renal fibrosis in the positive control (PC), whereas groups 3 and 4 noted an improvement in renal function nearly or equal to the healthy rats which were fed on a basal diet. Furthermore, the PC group showed significantly decreased levels of enzymatic antioxidants, namely SOD and GSH with a concomitant elevated MDA level compared with those in the negative rats fed on a basal diet. Groups 3 and 4 also reported improvements in enzyme activity. These results were further supported by histopathological findings which revealed a curative effect in groups 3 and 4, which avoided renal dysfunction and renal fibrosis from ethanol-induced toxicity. From the results, it can be said that the black rice extract with the highest amounts of antioxidants led to improvements in all parameters, especially kidney function, total protein, albumin, and globulin, in addition to enzyme activity. Therefore, black rice can be recommended as a benefit to general health.

Medicinal Applications of Banana Peel Flour Used as a Substitute for Computing Dietary Fiber for Wheat Flour in the Biscuit Industry

The aim of this study, medicinal applications of banana peel flour, was used to estimate nutrition value and minerals content. The results indicated that banana peel flour was safe for food application, and it was lower in protein and fat and higher in dietary fiber and total carbohydrate which were 52.68 and 67.25%, respectively. Moreover, the minerals content of phosphorous, potassium, sodium, manganese, and calcium were 217.92, 110.24, 96.43, 85.25, and 80.27 mg/100 g, respectively. Furthermore, the problem of the study investigated the effect of banana peel flour incorporation with wheat flour with 72% extraction to produce biscuit blends at different ratios of 5.0, 10.0, 15.0, and 20.0%, respectively. The nutrition value and mineral content of banana peel flour in biscuits increased gradually in the blends, according to the results. The methods of study of the four biscuit blends were prepared with banana peel flour substituted and wheat flour extraction of 72 percent, and they were compared to a control biscuit. Sensory properties reported that the control biscuit was the highest score followed by blends which had contained 5, 10, and 15% banana peel flour. Meanwhile, the blend of biscuit fortified with 20% was not accepted by panelists. From the color biscuits, the blends containing 5, 10, and 15% banana peel flour had acceptable color, and the blends' color was not acceptable. This may be caused by dark color and high dietary fiber. The texture profile analyzer and physical characteristics were confirmed and gave the same results. The result is that it could be recommended that the banana peel flour, which has high fiber content, produce acceptable biscuits fortified with 5, 10, and 15% and become functional foods. Panelists did not find the 20% blend biscuits to be particularly appealing.

In vitrofermentability and physicochemical properties of fibre substrates and their effect on bacteriological and morphological characteristics of the gastrointestinal tract of newly weaned piglets

Fermentability of fibre has a great impact on the bacterial flora along the gastrointestinal tract of newly weaned piglets. Therefore, this parameter was determined by incubating in vitro different fibre substrates (chicory roots, sugar beet pulp, wheat bran and corn cobs) with contents of jejunum or caecum sampled from slaughtered pigs. Incubating with small intestinal contents, lactic acid was the only fermentation product. Fermentability was highest for chicory roots, followed by wheat bran and sugar beet pulp, while corn cobs were not fermented. Based on SCFA formed in the incubations with caecal contents, ranking of the fermentability of the fibre substrates was in the same order. The effect of adding different fibre substrates to diets of newly weaned piglets on bacteriological and morphological aspects of the gastrointestinal tract was also investigated. In Experiment 1 three groups of five piglets, weaned at four weeks of age, received a control feed (C), C supplemented with corn cobs (50 g/kg) or with chicory roots (20 g/kg). In Experiment 2, diet C was supplemented with sugar beet pulp (120 g/kg) or with wheat bran (75 g/kg). After three weeks animals were euthanized and digesta were sampled from stomach, proximal and distal jejunum, caecum and colon. Furthermore, mucosal scrapings were prepared and tissue samples were taken from jejunum, caecum and colon. Viscosity was determined for jejunal, caecal and colon contents. Corn cobs in the feed increased the number of total bacteria, lactobacilli and bifidobacteria in the stomach and proximal duodenum, while a decreased count of streptococci in distal jejunum contents was noted. Chicory roots increased the counts of Escherichia coli in the distal jejunum and on the mucosa, while sugar beet pulp decreased the number of lactobacilli on the mucosa only. Wheat bran seemed to increase the count of E. coli in jejunal digesta and on the mucosa, and also the number of lactobacilli in the stomach and jejunum. Bifidobacterial numbers were increased but only in the proximal part of the jejunum. Fibre substrates affected the concentration of lactate and SCFA in different parts of the intestinal tract. Feeding corn cobs increased villus length in the proximal jejunum by 13%. The number of intra-epithelial lymphocytes in the villous epithelium of proximal and distal jejunum was decreased by corn cobs and chicory roots supplementation while beet pulp and wheat bran had the opposite effect. In Experiment 1, apoptotic index of the mucosa of the distal jejunum was very low and decreased when corn cobs were fed. Mitotic index in the crypts was only affected by the wheat bran diet and a small decrease was noted. It was concluded that the fermentability of fibre was not an ideal criterion for predicting its effects on the flora. The effect of fibres on viscosity of digesta was negligible probably explaining the lack of clear and consistent influences on the intestinal mucosa.

Early weaning stimulates intestinal brush border enzyme activities in piglets, mainly at the posttranscriptional level

BACKGROUND

Weaning-associated anorexia is the main factor responsible for structural alterations of the small intestine. However, whether weaning and the postweaning feed intake level affect disaccharidase and peptidase gene expression remains to be elucidated.

METHODS

Adaptation of the small intestine to early weaning at 7 days of age and the effects of postweaning feed intake were investigated on 56 pigs in two trials. Structural parameters and gene expression and activities of intestinal lactase, maltase, sucrase, aminopeptidases A and N, and dipeptidyl peptidase IV were determined along the small intestine.

RESULTS

Within 3 days, weaning induced increases in maltase, sucrase, and peptidase specific activities (P < 0.05) and a decrease in lactase activity and villous height (P < 0.05). Only for maltase activity were the weaning-induced changes closely correlated with corresponding mRNA levels. In weaned piglets, aminopeptidase N activity was consistently stimulated and dipeptidyl peptidase IV depressed by high level of feed intake but without effects on the corresponding mRNA levels. Furthermore, the longitudinal distribution of enzyme activities along the small intestine showed poor correlation with the corresponding mRNA levels.

CONCLUSION

Early weaning in pigs is associated with a remarkable capacity of the small intestine to rapidly increase the activity of key brush border enzymes. This adaptation, largely independent on feed intake for intestinal enzyme mRNAs and disaccharidase activities, occurred at the posttranscriptional rather than at the transcriptional level of enzyme biosynthesis (except for maltase). The length of the postweaning anorexia period did not affect the subsequent intestinal capacity for villous elongation but may postpone maturation of peptidase activities.

Incorporation of galactomannans in the diet of newly weaned piglets: Effect on bacteriological and some morphological characteristics of the small intestine

In search of substances replacing antibiotics as growth promoters for farm animals, non-digestible oligosaccharides (NDO) or non-starch polysaccharides (NSP) have been proposed as possible alternatives. In this context, the influence of galactomannans on bacteriological and morphological aspects of the gastrointestinal tract in weanling pigs was investigated. Four groups of five newly weaned piglets received one of the following diets: control feed (C), C supplemented with guar gum (1%), C supplemented with locust bean gum (1%) and C supplemented with 10% of carob tree seeds meal as source of locust bean gum. The animals were euthanized after 11-12 days and digesta were sampled in stomach, jejunum (proximal and distal) and caecum, while mucosal scrapings and ring shaped tissue samples were taken of proximal and distal jejunum. On these samples bacteriological, biochemical and morphological determinations were carried out. Total count of bacteria in digesta and mucosal scrapings was not influenced by the different diets, with the exception of the proximal jejunum where a small decrease (0.5 log10 CFU) was noted with the guar gum and carob tree seeds diet. The number of E. coli increased by feeding both gums and carob tree seeds. With the latter diet, higher counts of streptococci were observed. In agreement with the lower concentration of lactic acid in jejunal contents, guar gum decreased the number of lactobacilli. Locust bean gum decreased the molar proportion of acetate in caecal contents while butyrate and valerate were augmented. Feeding the carob tree seeds resulted in shorter villi and a lower villus height/crypt depth ratio in the jejunum mucosa, which was an indication for a faster renewal rate of the epithelium. Both locust bean gum feeds significantly lowered the mitotic index in the crypts of the small intestine. Only with the carob tree seeds diet, viscosity of jejunal contents was increased. In conclusion, the effects of the addition of 1% of pure guar gum or locust bean gum were inconsistent and not very outspoken, whereas 10% of carob tree seeds meal in the diet resulted in influences on intestinal characteristics at the bacteriological and morphological level.

Modulation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-induced mutation in the cecum and colon of big blue rats by conjugated linoleic acid and 1,2-dithiole-3-thione

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a potent mutagen and suspected human carcinogen present in cooked protein-rich food. It preferentially induced colon tumors in male rats and mammary tumors in female rats. In the present study, the in vivo antimutagenic efficacy of two dietary compounds, conjugated linoleic acid (CLA) and 1,2-dithiole-3-thione (DTT), against PhIP was explored using 1acI transgenic Big Blue rats. Five- or six-week-old male Big Blue rats were fed a diet containing CLA (0.5%, wt/wt) or DTT (0.005%, wt/wt) starting one week before exposure to 200 ppm PhIP for 61 days. PhIP treatment induced a approximately 8- to 16-fold increase in the mutation frequency (MF) in the colon. The induced MF was significantly lower in the cecum than in the proximal and distal colon (approximately 52 x 10(-5) vs. 100 x 10(-5), p < 0.008). CLA and DTT significantly reduced the PhIP-induced MF in the distal colon (p < 0.05) by 14% and 24%, respectively. The frequency of -1 frameshift mutations was lower in the distal colon of CLA- or DTT-treated rats. This protective effect was not observed in the cecum or in the proximal colon. In contrast, the PhIP-induced MF in the cecum (specifically, the frequency of -1 frameshifts and GC-->TA transversions) was elevated by 43% after treatment with CLA. In conclusion, CLA and DTT modulate PhIP-induced mutagenesis in a tissue-specific manner, and different modulation pathways are employed by CLA and DTT.

Low levels of viscous hydrocolloids lower plasma cholesterol in rats primarily by impairing cholesterol absorption

Hydrocolloids have been proposed as cholesterol-lowering agents, but their viscosity limits their use in human nutrition. A low level (1 %) of hydrocolloids (guar gum, (GG); xanthan gum, (XG); and konjac mannan) was investigated in rats fed 0.2 g/100 g cholesterol diets. Food intake and body weight gain were not altered by the diets. Bile flow and cholesterol bile flux were not modified by diet, whereas the bile acid flux was greater in rats fed hydrocolloid diets. The cecal pool of bile acids was greater than control rats only in rats fed the XG diet (+71%, P<0.001). The fecal excretion of neutral sterols was stimulated in rats fed the hydrocolloid diets; cholesterol apparent digestibility (60% in controls) was reduced to 30-36% in rats fed hydrocolloids. Bile acid fecal excretion was not altered by diet treatment. As a result, apparent steroid balance was about +40 micromol/d in controls and only +10 to +20 micromol/d in rats fed hydrocolloids. Both plasma cholesterol and triglycerides were significantly lower than controls in rats fed XG, but only cholesterol was lower in rats fed the GG diet. These effects were essentially found in the d <1.040 kg/L fraction. Liver cholesterol content was significantly lower than in controls in rats fed the GG or XG diets. Liver HMG CoA reductase was not affected by the hydrocolloid diets. In conclusion, a low percentage of viscous hydrocolloids lowers plasma cholesterol in cholesterol-fed rats. Inhibition of intestinal cholesterol absorption may be the primary mechanism.

Fecal losses of sterols and bile acids induced by feeding rats guar gum are due to greater pool size and liver bile acid secretion

The effect of dietary guar gum (GG, 7.5%) on lipid metabolism and on bile acid secretion and reabsorption was investigated in rats adapted to cholesterol-free or 0.3% cholesterol diets. Compared with controls (fiber-free/cholesterol-free), rats fed cholesterol had significantly elevated plasma and liver cholesterol and triglyceride. In these rats, GG had a potent plasma cholesterol-lowering effect and also counteracted the liver accumulation of triglyceride and cholesterol esters. Fecal excretion of sterols, the major route of cholesterol elimination, was markedly enhanced by GG, especially in rats fed the cholesterol-containing diet (P < 0.001). The biliary bile acid flux into the small intestine was enhanced by dietary cholesterol (+30%) or GG (+52%) or both (P < 0.001). The fecal excretion of bile acids was significantly elevated by GG alone (+74%) and by dietary cholesterol (+190%). Small intestine reabsorption of bile acids appears to be significantly enhanced by GG, which also enhanced the transfer of bile acids into the large intestine, hence a greater fecal loss of steroids, although bile acid reabsorption was very effective in the cecum. GG feeding induced liver hydroxymethyl-glutaryl coenzyme A (HMG CoA) reductase, even in cholesterol-fed rats, as well as cholesterol 7 alpha-hydroxylase (P < 0.001). The cholesterol-lowering effect of GG thus appears to be mediated by an accelerated fecal excretion of steroids and a rise in the intestinal pool and biliary production of bile acids. Although liver HMG CoA reductase and cholesterol 7 alpha-hydroxylase are induced in parallel, this is not sufficient to compensate for fecal steroid losses.

The effects of and interactions between fermentable dietary fiber and lipid in germfree and conventional mice

BACKGROUND/AIMS

Dietary fiber can stimulate intestinal epithelial cell proliferation. The aim of this study was to resolve the different roles of fermentation and intraluminal viscosity on this trophic action and to investigate reported interactions between fiber and dietary fat.

METHODS

Conventional and germfree mice were fed guar gum in combination with low- or high-lipid diets for 2 weeks, and crypt cell production rates were determined.

RESULTS

Guar gum significantly stimulated proliferation in the small intestine, especially when combined with fat. Lipid itself also stimulated proliferation in the small intestine and had a direct trophic effect in the cecum and colon of the germfree mice. Fiber markedly stimulated proliferation in the cecum and colon but only in the conventional group. Interactions between lipid and bacteria and between guar gum and bacteria were also observed in the small intestine.

CONCLUSIONS

Guar gum has a trophic effect in the small bowel, probably related to viscosity, in addition to its fermentation-related actions in the colon. Positive interaction with lipid may be associated with delayed absorption. Lipid also has its own direct actions on small bowel mucosal proliferation, which are attenuated by the presence of bacteria.

The effects of energy source and tryptophan on the rate of protein synthesis and on hormones of the entero-insular axis in the piglet

The present experiment was designed to study the influence of dietary energy source (fat or carbohydrate) and tryptophan (TRP) on protein synthesis and plasma insulin concentrations in the piglet. Six dietary regimens, based on either a high-fat (F) or a high-carbohydrate (C) diet with three levels of TRP (deficient, 1; adequate, 2; excess, 3), were used. Fractional protein synthesis rate (ks; % per d) was measured in the liver, Longissimus dorsi (LD), Semitendinosus (ST), skin, femur, brain, pancreas, stomach, mucosa of the duodenum and jejunum, and the whole body, using a 'flooding dose' of 3H-phenylalanine. Mean integrated insulin, gastric inhibitory polypeptide (GIP) and glucose concentrations were higher after the C diets compared with the F diets, TRP supplementation globally augmented ks linearly in the liver, ST, skin and whole body, while it had quadratic effects in the LD (ks highest in the TRP-adequate diet groups) and jejunal mucosa (ks lowest in the TRP-adequate diet groups). Pancreatic ks was increased by TRP addition up to a plateau. Ks was highest after the F diets in the digestive tissues while in the skin and LD ks was highest after the C diets. Fasting concentrations of gluconeogenic amino acids were lower (and urea higher) with the F than the C diets, suggesting their use as precursors for glucose synthesis. In conclusion, we have confirmed the depressive effects of TRP deficiency on ks, RNA activity and growth. We could not establish a relationship between plasma insulin and muscle ks. This may be related to the way in which we manipulated plasma insulin concentrations.