Physiological effects of lactulose and inulin in the caecum of rats

A model experiment was performed on rats to evaluate the effect of partial or total substitution of saccharose (S) and cellulose (C) by preparations of lactulose and inulin on the development and metabolism of the caecum. In the experimental diets given to rats for 4 weeks, the examined preparations were administered either with an equivalent amount of cellulose (each at 4% of the diet) or as sole source of dietary fibre at 8% of the diet. Compared to the saccharose group cellulose had no effect, and low doses of lactulose and inulin in the diet increased to a medium extent the weight of the caecum wall and caecal digesta. The addition of lactulose and inulin at 8% increased significantly the content of caecal digesta (4.62 and 4.11 g/100g BW, respectively) and the weight of the caecal wall (1.10 and 0.86 g/100g BW, respectively), compared to the groups with saccharose and cellulose (0.73, 0.90 and 0.24, 0.28 g/100g BW, respectively). Cellulose and cellulose partially-substituted with lactulose and inulin caused an increase in the dry matter content of caecal digesta (26.5-27.5%), compared to other groups (21.8-22.8%). The administration of lactulose and inulin preparations was accompanied by a significant drop in pH (5.47-5.81), compared to the groups with cellulose or saccharose (6.83-6.91), and a decrease in the ammonia concentration in the caecal digesta, compared to the cellulose control (0.27-0.40 and 0.62 mg/g, respectively). The group with 8% lactulose was characterized by the highest activities of microbiological alpha- and beta-galactosidase and beta-glucosidase in the caecal digesta. Cellulose and both preparations significantly decreased the activity of beta-glucuronidase, compared to the saccharose group (0.39-0.89 and 1.52 U/g, respectively). The highest concentration of VFA in the caecal digesta was observed in the saccharose group (89.2 micromol/g), and the lowest concentration in the group where cellulose was totally substituted by lactulose and inulin (55.1 and 57.5 micromol/g, respectively). The total production of VFA in the caecum was fourfold higher with 8 % lactulose and inulin (254.7 and 236.4 micromol/100g BW, respectively) than in both controls groups (65.1 and 67.8 micromol/100g BW, respectively). The high dose of inulin and lactulose increased the share of propionic acid in the VFA profile (C2:C3:C4) compared to both control groups. When 4% inulin was added to the diet a significant increase of butyrate concentration in the caecum was observed.     

Biological properties of fructooligosaccharides with different contents of kestose and nystose in rats

In a four-week experiment on rats' diets containing 5% of sucrose or fructooligosaccharides (FOS) diversified in terms of kestose and nystose contents: 6:1 (FOS-K), 3:1 (FOS-KN), and 0.5:1 (FOS-N) were applied. All FOS preparations, primarily FOS-N, considerably increased the mass of caecum, lowered pH of caecal digesta, and increased concentrations of protein. The glycolytic activity of the caecal digesta was generally alike in all groups, except for the control group where the activity of beta-glucosidase was negligibly lower and that of alpha-galactosidase higher. The administration of FOS preparation with a diet increased the concentration and the pool of total VFA in the caecal digesta, especially in the case of butyric and propionic acids and decreased the concentration of iso-butyric and valeric acids. When compared with the kestose-rich preparation, the nystose-rich preparation increased the production of total VFA in the caecum, primarily of n-butyrate and propionate. Different length of kestose and nystose chains had no effect on the activity of bacterial enzymes in the caecum nor the biochemical indices of serum, concentration of cholesterol, glucose, urea, Ca, P and Mg.     

Lactulose-induced diarrhoea in rats: effects on caecal development and activities of microbial enzymes

The intake of large amounts of lactulose and other non-digestible oligosaccharides can cause diarrhoea in rats and humans. The purpose of our study was to estimate tendency and scope of changes in caecum development, amount and composition of caecal digesta and activity of caecal microbial enzymes under the influence of lactulose-rich diet evoking or not evoking diarrhoea. Male Wistar rats were fed on 8%-lactulose diet for 4 weeks. Feeding with lactulose induced enlargement of the caecum (digesta and wall) compared to the control group. However, the hypertrophy of the caecal wall in rats with diarrhoea was less than in these without that ailment. Dry matter of caecal digesta was significantly decreased in rats with diarrhoea. Diarrhoea lowered concentrations of enzymatic protein and short-chain fatty acids in the caecum, and the activity of bacterial beta-glucuronidase, alpha- and beta-galactosidase, alpha- and beta-glucosidase in caecal digesta, compared to rats without diarrhoea. The ammonia concentration in the caecum was enhanced by diarrhoea symptoms. Occurrence of diarrhoea significantly deteriorated functioning of the caecal ecosystem what in turn limited potential benefits of diet supplementation with lactulose.     

Investigation on the precaecal and faecal digestibility of lactulose and inulin and their influence on nutrient digestibility and microbial characteristics

This study was conducted to determine the pre-caecal and faecal digestibility of lactulose and inulin and the influence of these substances on nutrient digestibility and microbial characteristics. In metabolic trials three of six male growing pigs (German Landrace?×?Pietrain) were fitted with an ileo-rectal anastomosis (IRA) in end-to-end technique with preserved ileo-caeco-colic valve. The metabolic trials were conducted from day 21?–?63 after surgery. The remaining pigs were used as intact partners (IN) for the IRA pigs. The experimental diets, based on corn, wheat, barley and soybean meal, were supplemented with either 1.5% lactulose or 2% inulin in replacement of diatomaceous earth (control). Pre-caecal digestibility of lactulose and inulin was assessed to be 79 and 98%, respectively, faecal digestibility was determined as 100%. The supplementation of lactulose and inulin had only minor effects on the pre-caecal and faecal digestibility of nutrients. Significant differences in nutrient digestibility were obvious between IRA and IN pigs, whereas the IRA pigs showed lower digestibility values with the exception of ether extracts (EE). Bacterial population in the digesta of IRA and IN pigs were not affected by the experimental diets except the concentration of gram-negative anaerobes, which inclined when the IRA pigs received the lactulose diet. The pH of chyme was significantly lower than the pH of faeces, however the pH was unaffected by the different supplemented diets. The concentration of volatile fatty acids (VFA) in pre-caecal chyme decreased significantly when IRA pigs received the lactulose supplemented diet whereas VFA in faeces were unaffected by the supplementation. IRA pigs administered with lactulose excreted more N via the urine, but the nitrogen balance remained unaffected. From the present investigation it can be concluded that lactulose and inulin did only partly or scarcely fulfill the expectation of acting as prebiotics in pigs.     

Biological properties of fructooligosaccharides with different contents of kestose and nystose in rats

Abstract

In a four-week experiment on rats' diets containing 5% of sucrose or fructooligosaccharides (FOS) diversified in terms of kestose and nystose contents: 6:1 (FOS-K), 3:1 (FOS-KN), and 0.5:1 (FOS-N) were applied. All FOS preparations, primarily FOS-N, considerably increased the mass of caecum, lowered pH of caecal digesta, and increased concentrations of protein. The glycolytic activity of the caecal digesta was generally alike in all groups, except for the control group where the activity of β-glucosidase was negligibly lower and that of α-galactosidase higher. The administration of FOS preparation with a diet increased the concentration and the pool of total VFA in the caecal digesta, especially in the case of butyric and propionic acids and decreased the concentration of iso-butyric and valeric acids. When compared with the kestose-rich preparation, the nystose-rich preparation increased the production of total VFA in the caecum, primarily of n-butyrate and propionate. Different length of kestose and nystose chains had no effect on the activity of bacterial enzymes in the caecum nor the biochemical indices of serum, concentration of cholesterol, glucose, urea, Ca, P and Mg.     

Effects of cellulose, carboxymethylcellulose and inulin fed to rats as single supplements or in combinations on their caecal parameters

We compared the effect of diets containing different nondigestible carbohydrates: cellulose (C), inulin (IN) and carboxymethylcellulose (CMC) as single supplements or in dietary combination on caecal physiology of rats. Sixty male Wistar rats (Rattus norvegicus) were divided into five groups and for 4 weeks were fed a casein diet with the compared carbohydrates (4% of diet) or a combination of IN+C or IN+CMC (both 4+4%). Diet intake and FCR index remained unaffected by the treatments, whereas IN improved the body weight gain of rats compared to CMC. Compared to C group, all diets containing IN and CMC decreased the caecal pH as well as enlarged the caecum, thus increasing the weights of contents and tissue, especially upon CMC treatment. Rats given carboxymethylcellulose (CMC and IN+CMC groups) had watery caecal digesta, and some of them suffered from diarrhoea. In the case of CMC, the caecal enlargement was due to tissue hypertrophy and digesta accumulation mostly in response to an increased bulk of contents. Unlike C+IN, the dietary combination of CMC- and inulin-enhanced fermentation in the caecum of rats, however the proportion of acetate, propionate and butyrate was less beneficial. Compared to CMC, inulin gave a higher concentration of SCFA, especially of butyrate and propionate. The action of inulin in the caecum of rats could be pronounced by dietary treatment combined with CMC.     

Caecal parameters of rats fed diets supplemented with inulin in exchange for sucrose

Abstract

The effects of different modes of inulin supplementation on caecal fermentation were evaluated in rats. Groups S and IN were fed diets containing 5% of sucrose or inulin, respectively, for the whole experimental period of 40 days. Group IN/S was fed IN and S diets, whereas group S/IN was fed S and IN diets, in the first and the second 20-day period, respectively. Groups IN_up and IN_down were fed diets in which the content of inulin increased from 1 – 5% and decreased from 5 – 1%, every 8 days, respectively. The common effects of inulin on caecal fermentation, i.e. enlargement of tissue, acidification of digesta, a decrease in activities of potentially harmful bacterial enzymes (β-glucuronidase and β-glucosidase), and an increase in the total volatile fatty acids concentration and pool, were especially observed in the IN, S/IN and IN_up groups. The results suggested that the intensity of caecal fermentation is increased when inulin is present at a relatively high dietary level and that these changes are easily reversible after inulin withdrawal from feed.     

Investigation on the precaecal and faecal digestibility of lactulose and inulin and their influence on nutrient digestibility and microbial characteristics

This study was conducted to determine the pre-caecal and faecal digestibility of lactulose and inulin and the influence of these substances on nutrient digestibility and microbial characteristics. In metabolic trials three of six male growing pigs (German Landrace x Pietrain) were fitted with an ileo-rectal anastomosis (IRA) in end-to-end technique with preserved ileo-caeco-colic valve. The metabolic trials were conducted from day 21-63 after surgery. The remaining pigs were used as intact partners (IN) for the IRA pigs. The experimental diets, based on corn, wheat, barley and soybean meal, were supplemented with either 1.5% lactulose or 2% inulin in replacement of diatomaceous earth (control). Pre-caecal digestibility of lactulose and inulin was assessed to be 79 and 98%, respectively. faecal digestibility was determined as 100%. The supplementation of lactulose and inulin had only minor effects on the pre-caecal and faecal digestibility of nutrients. Significant differences in nutrient digestibility were obvious between IRA and IN pigs, whereas the IRA pigs showed lower digestibility values with the exception of ether extracts (EE). Bacterial population in the digesta of IRA and IN pigs were not affected by the experimental diets except the concentration of gram-negative anaerobes, which inclined when the IRA pigs received the lactulose diet. The pH of chyme was significantly lower than the pH of faeces, however the pH was unaffected by the different supplemented diets. The concentration of volatile fatty acids (VFA) in pre-caecal chyme decreased significantly when IRA pigs received the lactulose supplemented diet whereas VFA in faeces were unaffected by the supplementation. IRA pigs administered with lactulose excreted more N via the urine, but the nitrogen balance remained unaffected. From the present investigation it can be concluded that lactulose and inulin did only partly or scarcely fulfill the expectation of acting as prebiotics in pigs.     

In vivo study of cecal fermentation activity in the rabbit. Completion and validation of a new technique for cecal cannulation]

A new technique for caecal cannulation in adult rabbit was validated in order to perform in vivo studies of caecal fermentation under a physiological status. The cannulation did not modify the digestibility of the diet, and it was possible to collect digesta (10 g fresh matter) after a few minutes without stress for animals only 10 days post-surgery. Volatile fatty acid (VFA) (60 mM/l) and ammonia (11 mM/l) concentration of caecal digesta collected in vivo was not different from that obtained from slaughtered rabbits. VFA measurements were reproducible (CV = 6.8%) and were not dependent on the daily collection frequency (1-5/day). Caecal VFA level in the starved rabbit was very low (23 mM/l) while the butyrate/propionate rate was the inverse (C4/C3 = 0.6). Five h after feeding, the in vivo VFA level reached 96 mM/l and the butyrate proportion (12%) over-reached those of propionate (3.5%). The caecal fermentations of a 7-week-old rabbit differed from those of an adult by a higher VFA level and by a greater post-feeding variation in the fermentation pattern.     

Effects of age and mannanoligosaccharides supplementation on production of volatile fatty acids in the caecum of rabbits

This trial studied the effect of including mannanoligosaccharides (MOS, Bio-Mos^®, Alltech Inc., USA) in the diet on the caecal volatile fatty acids (VFA) and pH of rabbits from 34 to 90 days of age. Three experimental diets were compared: control diet, zinc bacitracin (ZnBac) diet (control diet with 0.1 g ZnBac/kg feed) and MOS diet (control diet with 2.0 g MOS/kg feed). Rabbits were slaughtered at 34, 48, 69 and 90 days of age and caecal contents were collected and analyzed for dry matter, pH and VFA concentration. The empty caecum and caecal contents weights relative to live weight were also determined.Age affected (P<0.0001) VFA concentration and pH values in the caecum. The pH decreased with age whereas VFA concentration increased. Rabbits fed MOS had higher (P<0.05) VFA and tended (P=0.098) to had lower pH in the caecum than rabbits fed ZnBac and control diets. Acetic, propionic and butyric acids concentrations in the caecum increased with MOS but its molar proportions were similar among diets. Diet had no effect on empty caecum weight and caecal contents weight and dry matter concentration. There was no interaction effect between diet and age. From 34 to 90 days of age, VFA production was higher (P<0.05) in the caecum of rabbits fed MOS than in those fed ZnBac diet and control diet.The addition of MOS to the diet increased the VFA concentration in the caecum of growing rabbits from 34 to 90 days of age.     

Effect of substrate and feed antibiotics on in vitro production of volatile fatty acids and methane in caecal contents of chickens

An attempt was done to identify some factors influencing the caecal fermentation pattern in poultry. Experiments were conducted to study effects of carbohydrate substrates (feed components and supplements) and antibiotics on the formation of volatile fatty acids (VFA) and methane in in vitro incubations of the caecal contents of 7-week-old chickens. Stoichiometry of fermentation differed in cultures with different carbohydrates. Fermentation pattern characterized by high propionate and low acetate production was found in cultures with lactose (0.447 and 0.376 mol/1 mol of VFA produced, respectively) and, to a lesser extent, also in cultures with raffinose. Acetate was the predominant metabolite of starch, pectin and xylan (0.727, 0.773 and 0.685 mol/1 mol of VFA produced, respectively). Fermentation of inulin resulted in high proportion of butyrate, 0.221 mol/1 mol of VFA. Other polysaccharides produced only 0.060–0.111 mol of butyrate per 1 mol of VFA. Oligosaccharides (lactose, raffinose) were fermented more rapidly than polysaccharides. Fermentation of inulin yielded more VFA than fermentation of starch, pectin and xylan. No production of VFA from carboxymethylcellulose was observed. On average, 11 mols of VFA were produced per mol of methane. Lasalocid significantly increased molar proportion of propionate, which is potentially beneficial from the point of view of salmonellae control. The magnitude of improvement, however, was small. Other feed antibiotics tested (avoparcin, bacitracin, lincomycin, spiramycin, tylosin, virginiamycin) produced only non-significant or marginal fermentation shifts. Formation of valerate, isoacids and methane was not significantly influenced by the substrate or by antibiotic treatment.     

Effect of inulin supplementation on selected gastric, duodenal, and caecal microbiota and short chain fatty acid pattern in growing piglets

We explored whether bifidobacteria and lactobacilli numbers and other selected bacteria in the upper intestine and the caecum of growing pigs were affected by diet and intake of inulin. Starting at two weeks after weaning (28 d) 72 pigs were fed two types of diets (wheat/barley (WB) or maize/gluten (MG)), without or with 3% inulin (WB + I, MG + I) for three and six weeks. Intestinal bacteria were quantified by fluorescence-in-situ-hybridization (n = 8/group). Duration of feeding had no effect on the variables tested, so data for both periods were pooled. Gastric total bacteria amounted to log(10) 7.4/g digesta. Bifidobacteria were detected in stomach and duodenum two weeks after weaning and disappeared thereafter. In jejunum and caecum bifidobacteria were present at a level of log(10) 7.0/g digesta. Inulin did not alter numbers of lactobacilli, bifidobacteria, enterococci, enterobacteria and bacteria of the Clostridium coccoides/Eubacterium rectale-group. Inulin disappearance in stomach plus jejunum was higher with the MG diet (73.7 vs. 60.7%, p = 0.013). Caecal acetate was lower in inulin-supplemented diets (p < 0.05) whereas propionate and butyrate were higher in pigs fed the WB diets (p < 0.05). With the WB diet total caecal short chain fatty acids concentration was higher which resulted in a lower pH value (p < 0.05).     

Caecal parameters of rats fed diets supplemented with inulin in exchange for sucrose

The effects of different modes of inulin supplementation on caecal fermentation were evaluated in rats. Groups S and IN were fed diets containing 5% of sucrose or inulin, respectively, for the whole experimental period of 40 days. Group IN/S was fed IN and S diets, whereas group S/IN was fed S and IN diets, in the first and the second 20-day period, respectively. Groups IN(up) and IN(down) were fed diets in which the content of inulin increased from 1-5% and decreased from 5-1%, every 8 days, respectively. The common effects of inulin on caecal fermentation, i.e. enlargement of tissue, acidification of digesta, a decrease in activities of potentially harmful bacterial enzymes (beta-glucuronidase and beta-glucosidase), and an increase in the total volatile fatty acids concentration and pool, were especially observed in the IN, S/IN and IN(up) groups. The results suggested that the intensity of caecal fermentation is increased when inulin is present at a relatively high dietary level and that these changes are easily reversible after inulin withdrawal from feed.     

Effect of substitution of wheat starch by potato starch on the performance,digestive physiology and health of growing rabbits

The goal of this research was to study the effect of the substitution of wheat starch by potato starch (PS) on the performance, health and digestion of growing rabbits. Three experimental diets were formulated with 0%, 7% and 14% PS (PS0, PS7 and PS14, respectively) and similar starch contents (22% dry matter basis), proteins and fibre. The three diets were administered to three groups of 48 rabbits from weaning (28 days) to slaughter (70 days), and growth and health measurements were made. Another 10 rabbits per diet (30 rabbits at each age), reared under similar conditions, were slaughtered at 6 to 10 weeks of age, and the digesta were collected to analyse the caecal microbial activity (pH, volatile fatty acids (VFA) levels, fibrolytic activity) and the starch concentration in the ileal digesta. At the same ages, the whole tract digestibility coefficients were measured in 10 other rabbits for each treatment (30 rabbits). The feed intake between 28 and 42 days of age (days) increased by 11% (P < 0.05) in PS0 v. PS14. Over the whole growth period (28 to 70 days), weight gain was similar among diets (40.5 g/day), whereas the feed intake and feed conversion increased (8.5% and 5.2%, respectively; P < 0.05) with the PS14 diet. Mortality and morbidity were not affected by the diets. The starch concentration of the ileal contents increased (P < 0.01) with the addition of PS to the diet (0.39%, 0.77% and 1.08% for diets PS0, PS7 and PS14, respectively). Starch digestibility was 0.8 percentage units higher (99.8% v. 99.0%) with the PS0 diet than the PS14 diet (P = 0.04). The bacterial cellulolytic activity in the caecum tended to be higher with the PS14 diet (P = 0.07). The total VFA caecal concentration increased (P < 0.01) only in 6-week-old rabbits with PS7 compared with PS0 (54.7 v. 74.5 mmol/l). Protein digestibility and ileal starch concentration decreased (P < 0.05) with age (6 v. 10 weeks), and hemicelluloses digestibility increased (P < 0.05). At 10 weeks of age, rabbits showed a higher VFA pool (6.25 mol) and proportion of butyrate (15.9%) and a lower proportion of acetate (79.3%), ammonia level (7.5 mmol/l) and C3/C4 ratio (0.31) than at 6 weeks of age. The intake of potato starch had no effect on the performance, caecal microbial activity or digestive health of growing rabbits.     

Different effects of difructose anhydride III and inulin-type fructans on caecal microbiota in rats

The effects of different kinds of inulin-type fructans on caecal microbiota were evaluated in rats. Four groups of male Wistar rats were fed either a control diet, or diets containing 5% inulin, 5% fructooligosaccharides (FOS), or 5% difructose anhydride III (DFAIII) for two weeks. In the DFAIII group, caecal propionate, butyrate, counts of bifidobacteria, and total anaerobes were lower than in the inulin group, while caecal propionate, succinate, counts of bifidobacteria, and total anaerobes were lower than in the FOS group. Compared to controls, in the DFAIII group the counts of clostridia in caecum were increased by 3 log units. However, this change was statistically not significant. There were no differences between inulin and FOS groups for the pool of short chain fatty acids in caecum and bacterial counts. Results indicate that DFAIII has different effects on caecal microbiota compared to inulin and FOS and that these differences are most likely due to the alpha(3-->2) bonds in DFAIII.     

Different effects of difructose anhydride III and inulin-type fructans on caecal microbiota in rats

Abstract

The effects of different kinds of inulin-type fructans on caecal microbiota were evaluated in rats. Four groups of male Wistar rats were fed either a control diet, or diets containing 5% inulin, 5% fructooligosaccharides (FOS), or 5% difructose anhydride III (DFAIII) for two weeks. In the DFAIII group, caecal propionate, butyrate, counts of bifidobacteria, and total anaerobes were lower than in the inulin group, while caecal propionate, succinate, counts of bifidobacteria, and total anaerobes were lower than in the FOS group. Compared to controls, in the DFAIII group the counts of clostridia in caecum were increased by 3 log units. However, this change was statistically not significant. There were no differences between inulin and FOS groups for the pool of short chain fatty acids in caecum and bacterial counts. Results indicate that DFAIII has different effects on caecal microbiota compared to inulin and FOS and that these differences are most likely due to the α(3→2) bonds in DFAIII.     

Physiological effects of chicory root preparations with various levels of fructan and polyphenolic fractions in diets for rats

The experiment was aimed at studying the effects of easily fermentable oligosaccharides and phenolic compounds from chicory root meal (CRM) on the fermentative processes in the caecum, the antioxidative status and the lipoprotein profile of rats. Five different diets were fed ad libitum to 40 Wistar rats (eight animals per group, individually housed): a control group (C); group PCM (10% processed CRM, deprived of polyphenolic fraction); group PCMO (8% processed CRM and 1.6% oligofructose); group UCM (10% unprocessed CRM); and group FP (8.3% fructan-polyphenol concentrate from CRM). Diets PCM, PCMO, UCM and FP induced favourable metabolic changes in the caecum, blood lipid profile and the antioxidative status of the body. In the caecum, the experimental diets increased the production of volatile fatty acids (VFA) and acidification of digesta as well as a decrease in the ammonia concentration and bacterial beta-glucuronidase activity. In blood serum, the total cholesterol concentration was reduced and, simultaneously, the proportion of HDL in the total cholesterol concentration was increased. The presence of the polyphenolic fraction in the unprocessed meal (diets UCM and FP) evoked a significant increase in the total antioxidative status in blood serum. Dietary fibre and the polyphenolic fraction present in diet UCM and the FOS-polyphenol concentrate in diet FP did not exhibit an antagonistic activity regarding the physiological parameters analysed, except for in the intensity of caecal fermentation. The results of the experiment point to the benefits of dietary supplementation with chicory preparations containing both prebiotic saccharides and polyphenolic compounds, which enable us to take advantage of the physiological traits of both components.     

Gastrointestinal tract metabolism of young turkeys fed diets supplemented with pure nystose or a fructooligosaccharide mixture

In a four-week experiment on 60 7-day-old BUT-9 male turkeys the effects of dietary fructooligosaccharides (pure nystose and a fructooligosaccharide mixture) supplemented at 1 and 2%, were studied on ileal and caecal metabolism. The control carbohydrate was cellulose, added also at 1 or 2%. Each dietary treatment consists of 10 birds kept individually. The average degree of polymerisation of the nystose and oligofructose preparation amounted to 2.9 and 4.1, respectively. The addition of nystose significantly decreased the pH value and viscosity in the ileal contents compared with the cellulose treatment. On the other hand, the oligofructose preparation increased the activity of sucrase and lactase in the ileal mucosal by 30-60% and 33-47%, respectively. Both fructan preparations similarly acidified the caecal and colonic digesta (by 0.2-0.4 pH units) as well as diminished the activity of bacterial harmful beta-glucuronidase (by 24-40%), but only nystose caused an enlargement of the caeca and effectively reduced caecal ammonia concentration, especially at a higher dose. Oligofructose supplementation at 2% caused a 3.5-fold increase of bacterial activity of alph- and beta-galactosidase, while 2% nystose resulted in 1.7 and 3 times higher alpha- and beta-glucosidases activities, respectively. Compared to oligofructose, dietary nystose increased propionic and decreased butyric fermentation in caeca. Nystose and oligofructose preparations added at 2% reduced the triacylglycerol concentration in the serum in comparison to the addition of 2% cellulose by 46 and 25%, respectively. Beside the fact that dietary levels of supplementation were of great importance, the results indicated that even small difference in the length of carbohydrate chain may cause different physiological responses.     

Effects of dietary lipids and Clostridium butyricum on the performance and the digestive tract of broiler chickens

The effects of two sources of dietary lipids and supplementation of Clostridium butyricum on performance and intestinal metabolism of broilers were investigated. In a 2 x 2 factorial arrangement, 168 one-day-old broiler chicks were divided into four treatment groups, and fed four diets with two lipid sources (soya bean oil or fish oil, at 25 g/kg and 30 g/kg in starter and grower diets respectively), and without or with supplementation of C. butyricum (1 x 10(9) colony forming units per kg diet). C. butyricum had no effect on broiler performance. At 20 and 40 d of age, the pH of caecal digesta and the relative length of caecum were decreased after supplementation of C. butyricum (p < 0.05). After this treatment, the activity of alkaline phosphatase was increased in jejunal mucosa at 40 d of age (p < 0.01). Furthermore, there were increases in populations of lactic acid bacteria and the concentrations of acetic acid, n-butyric acid, n-valeric acid and total short chain fatty acids in caecal digesta of birds fed C. butyricum (p < 0.05). A significant interaction between lipid source and C. butyricum was found in the pH of caecal digesta at 20 d of age (p < 0.01). The results of the present study indicated that dietary supplementation of C. butyricum maybe a benefit for gut health of broiler chickens.     

The effect of high and low dietary crude protein and inulin supplementation on nutrient digestibility, nitrogen excretion, intestinal microflora and manure ammonia emissions from finisher pigs

A 2 × 2 factorial experiment was performed to investigate the interaction between a high- and low-crude-protein (CP) diet (200 v. 140 g/kg) and inulin supplementation (0 v. 12.5 g/kg) on nutrient digestibility, nitrogen (N) excretion, intestinal microflora, volatile fatty acid (VFA) concentration and manure ammonia emissions from 24 boars (n = 6, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy and lysine. Pigs offered the high-CP diets had a higher excretion of urinary N (P < 0.001), faecal N (P < 0.01) and total N (P < 0.001) than the pigs offered the low-CP diets. Inulin supplementation increased faecal N excretion (P < 0.05) and decreased the urine N : faeces N ratio (P < 0.05) compared with the inulin-free diets. There was no effect (P > 0.05) of dietary treatment on N retention. There was an interaction (P < 0.05) between dietary CP concentration and inulin supplementation on caecal Enterobacteria spp. Pigs offered the diet containing 200 g/kg of CP plus inulin decreased the population of Enterobacteria spp. compared to those with the inulin-supplemented 140 g/kg CP diet. However, CP level had no significant effect on the population of Enterobacteria spp. in the unsupplemented diets. Inulin supplementation increased caecal Bifidobacteria (P < 0.01) compared with the inulin-free diets. There was no effect of inulin supplementation on VFA concentration or intestinal pH (P > 0.05). Pigs offered the 200 g/kg CP diets had higher (P < 0.05) manure ammonia emissions from 0 to 240 h of storage than pigs offered the 140 g/kg CP. In conclusion, inulin supplementation resulted in an increase in Bifidobacteria concentration and a reduction in Enterobacteria spp. at the high CP level indicating that inulin has the ability to beneficially manipulate gut microflora in a proteolytic environment.