Relative Caecal Weight Research Articles

Effects of Different Dietary Levels of Whey Lactose as a Prebiotic Disaccharide on the Productive Performances and Selected Indices of the Caecal Micro-Environment in Broiler Chickens

Abstract The primary aim of this study was to investigate the impact of three dietary levels of lactose (LAC) originating from conventional dried whey (DW) and the duration of these treatments (from 8 to 21 or to 42 days of age) on growth performance, basic post-slaughter traits and excreta quality of broiler chickens kept in cages. A secondary purpose was to investigate the effect of LAC level on some parameters of the caecal micro-environment and gross morphology in these birds. A total of 560 Ross 308 chickens (sex ratio 1:1) were assigned to 7 dietary combinations with 10 replicate cages of 8 birds per cage. The control group was fed basal diets consisting of maize, wheat and soybean meal. The other 6 groups received the same basal diets with DW added in amounts equivalent to a LAC dietary levels of 1, 2 or 3%. Only continuous feeding (day 8 to 42) with 1% and 2% levels of LAC was found to yield the overall body weight gain (BWG) during the whole 42-day rearing period, which was significantly higher than that on the control diet, with a larger share of breast meat in carcass at a 2% LAC. However, these effects were associated with greater faecal score values indicating more watery excreta compared with the control. Increasing levels of LAC augmented the relative caecal weight and length. A reduction in the caecal pH was confirmed at day 21 for birds fed 1% and 2% of dietary LAC. The lower pH values were correlated to an increased sum of total volatile fatty acids (VFA), causing large increases in the concentration of undissociated forms of individual VFA. The decline in plate counts of coliform bacteria was observed with 2% and 3% LAC, whereas the counts of lactic acid-producing bacteria (LAB) were higher at these two LAC levels. The present findings lead to the conclusion that the dietary level of 2% LAC originated from DW is the most effective in enhancing the productivity of broilers, with moderate occurrence of undesirable side effects.

Influence of whole wheat inclusion and a blend of essential oils on the performance, nutrient utilisation, digestive tract development and ileal microbiota profile of broiler chickens

1. The aim of the present experiment was to examine the influence of whole wheat inclusion and a blend of essential oils (EO; cinnamaldehyde and thymol) supplementation on the performance, nutrient utilisation, digestive tract development and ileal microbiota profile of broiler chickens. 2. The experimental design was a 2 × 2 factorial arrangement of treatments evaluating two wheat forms (ground wheat [GW] and whole wheat [WW]; 100 and 200 g/kg WW replacing GW during starter [1 to 21 d] and finisher [22 to 35 d] diets respectively) and two levels of EO inclusion (0 or 100 g/tonne diet). All dietary treatments were supplemented with 2000 xylanase units/kg feed. Broiler starter and finisher diets based on wheat and soybean meal were formulated and each diet fed ad libitum to 6 pens of 8 male broilers. 3. During the trial period (1–35 d), wheat form had no significant effect on weight gain or feed intake. However, WW inclusion tended (P = 0.06) to improve feed per gain. Essential oil supplementation significantly improved weight gain in both diets, but the improvements were greater in the GW diet as indicated by a significant wheat form × EO interaction. 4. Main effects of wheat form and EO on the relative weight, length and digesta content of various segments of the digestive tract were not significant. Significant interactions, however, were found for relative gizzard and caecal weights. Essential oil supplementation significantly increased the relative gizzard weight and lowered relative caecal weight in birds fed on the GW based diet, but had no effect in those fed on the WW based diet. 5. Whole wheat inclusion and EO supplementation significantly improved apparent ileal nitrogen digestibility. Apparent ileal digestible energy was not significantly influenced by the dietary treatments. 6. Ileal microbiota profiling, using denaturing gradient gel electrophoresis, showed that the ileal microbiota composition was influenced by feed form. The mean numbers of bacterial species in the ileal contents of birds fed on the GW diet supplemented with EO tended (P = 0.07) to be higher than those of the ileal contents of birds fed on unsupplemented GW based diet. 7. The present data suggested that dietary addition of EO improves broiler weight gain and ileal nitrogen digestibility both in GW and WW based diets, but that the magnitude of the response to EO for weight gain was greater in GW based diet. Whole wheat feeding was found to be beneficial in terms of feed efficiency.

Influence of Antimicrobial Drugs on Segmented Filamentous Bacteria in the Ileum of Mice

The effects of various types of 3 d antibiotic treatment of mice on the presence of segmented filamentous bacteria (SFBs) in the ileum were measured in order to further characterise these microorganisms. To assess any specific effects of the antimicrobial drugs on SFBs, relative caecal weight, relative number of fusiform-shaped bacteria in the caecum and the number of faecal Enterobacteriaceae were also determined. All drugs tested, i.e. amoxycillin, doxycyclin, gentamicin, vancomycin, ciprofloxacin, trimethoprim, metronidazole, clindamycin, streptomycin and cefotaxim, reduced the presence of SFBs in the ileum, although to different degrees. None of the drugs affected body weight of the mice. There was no correlation of the drug effects on SFBs and those on either relative caecal weight, percentage of caecal fusiforms or faecal Enterobacteriaceae. Thus, the effects of the antimicrobial drugs on SFBs can be considered rather specific. The sensitivity pattern of SFBs suggests that they are facultatively anaerobic bacteria with relatively high sensitivity to antimicrobial drugs. Keywords: Segmented filamentous bacteria; Intestinal bacteria; Small intestine; Mouse; Antibiotics.

Influence of Macronutrients on Segmented Filamentous Bacteria in the Small Intestine of Mice

Segmented filamentous bacteria (SFBs) in the ileum of mice were poorly present after the feeding of milk powder as sole source of nutrition, but were abundant in animals fed on a diet based on natural ingredients. Twenty-one different purified diets were formulated so that clues could be obtained to identification of the macronutrients that may be responsible for the differential SFB promoting effects of milk powder and the natural ingredient diet. None of the purified diets induced the appearance of SFBs, suggesting that the type and amount of fat, the type ofcarbohydrate and the amount and type of fibre in the diet do not influence SFB colonisation. Alternatively, the purified diets could have lacked a substance which was present in the natural ingredient diet and is essential for SFB colonisation. Thus, although we were not able to identify nutritional factors of SFBs, it is clear that the composition of the diet is at least one factor that determines whether or not SFBs appear in the ileum of mice. Colonisation levels of SFBs in mice fed experimental diets were not associated with relative caecal weight, the percentage of fusiform-shaped bacteria in the caecum or the number of Enterobacteriaceae present in faeces. The latter three parameters were however, significantly influenced by the composition of the purified diets. Keywords: Segmented filamentous bacteria; Intestinal bacteria; Macronutrients; Mouse.

The use of a rat-derived microflora for providing colonization resistance in SPF rats

To obtain a suitable species-specific microflora for a new rat SPF-unit, germ-free WAG/Rij rats were associated with a flora derived originally from selectively decontaminated Cpb: WU (Wistar) rats. Caecal and ileal contents of these rats had been cultured anaerobically (37 degrees C) for 7 days and harvested. This cultured flora was given to germ-free Cpb: SE (Swiss) mice, which were kept in an isolator system and acted as a source of the flora to associate germ-free Wag/Rij rats. In these associated rats, several parameters indicative of the 'quality' of the intestinal microflora were investigated and compared to those in rats with a mouse derived anaerobic microflora. Parameters included relative caecal weight, colonization resistance and the concentration of faecal bile acids. The cultured rat-derived microflora normalized the observed intestinal parameters better than the mouse derived microflora, and provided better colonization resistance. We conclude that culturing of intestinal contents of selectively decontaminated animals can be a useful way to obtain a species-specific donor-microflora which can be used to start new SPF units.

Effect of Preventing Coprophagy on Colonisation by Segmented Filamentous Bacteria in the Small Bowel of Mice

Segmented filamentous bacteria (SFBs) are present in the small intestine of mice and rats. It is not clear whether this presence is due to a stable colonisation or to reinfection by coprophagy. To answer this question the effect of preventing coprophagy on SFBs was studied in mice. Two parameters were determined as general indicators for a normal microecological state of the small intestine: the relative caecal weight and the percentage of caecal fusiform shaped bacteria. Prevention of coprophagy executed by means of a polyethylene ‘restrainer’ and a wire mesh resulted in a slight increase in the colonisation of SFBs (significant in small intestine section 8; p < 0.012). The number of SFBs per 100 bacteria showed an increase in section 8 compared to mice with a restrainer, but which were housed on sawdust ( p < 0.032). No effects were seen on the relative caecal weight and the percentage of fusiform shaped bacteria in the caecum. Keywords: Intestinal bacteria; Colonisation; Mouse.

SPFマウス腸内菌叢の生産施設差

Specific pathogen free BALB/c mice from 3 commercial laboratory animal breeders in Japan were compared on the composition of caecal flora revealed by selective and nonselective cultivation as well as direct microscopical observation on smears, and relative caecal weight. Large differences were detected in viable counts of total bacteria and almost all bacterial groups, while direct microscopical counts which consisted mainly of fusiform bacteria were almost equal, resulting in diverse recovery rates among 3 breeders. Eubacterium and spiral shaped organisms were not detected from all breeders. There also existed variations within breeders, especially those in the number of Enterobacteriaceae. Relative caecal weight also differed among breeders, suggesting the participation of variety of caecal bacteria in determining this parameter. As these variations in bacteriological status of animals can influence experimental results, standardization of intestinal microbial flora is required.

The 'normalization' of germ-free guineapigs with host-specific caecal microflora.

Hysterectomy-derived germ-free guineapigs were given colonization-resistant caecal flora from mice (mCRF) or microflora obtained from the caecum of an antibiotic-decontaminated conventional guineapig (gpCRF) and compared with guineapigs raised conventionally with the sow. Body weight and the following intestinal parameters were determined for the groups: colonization resistance (CR) to Escherichia coli, relative caecal weight (RCW), beta-aspartylglycine (faeces), volatile fatty acids (caecum) and bile acids (faeces). mCRF guineapigs showed values quite different from control animals for CR and RCW, indicating the unsuitability of mouse CRF for normalizing guineapigs. In gpCRF guineapigs CR and RCW values were comparable with controls, indicating the suitability of the guineapig flora for normalizing guineapigs. mCRF guineapigs housed with gpCRF guineapigs, showed an improvement in CR and RCW, yielding values found in control animals.

The influence of stress and cheese-whey on intestinal parameters in mice.

In a mouse model the effects of environmental stress on gastrointestinal parameters and the effects of cheese-whey on the changes induced by stress were studied. Mice were subjected to overcrowding, lack of bedding, overcrowding together with lack of bedding, continuous light, and housing at 30 degrees C. The influence of stress on relative caecal weight, faecal enterobacteriaceae, colonisation resistance (CR), filamentous segmented bacteria in the small intestine, fusiform bacteria in the faeces, and concentration of faecal bile acids was studied. Stress had no influence on relative caecal weight, faecal enterobacteriaceae, and faecal bile acids. Stress did decrease colonisation resistance, presence of segmented filamentous bacteria in the small intestine, and fusiform bacteria in the faeces. Cheese-whey had no positive effect on the microbiological disturbances caused by stress. The number of filamentous segmented bacteria in the small intestine and fusiforms in the faeces decreased by giving cheese-whey.

Elimination of murine viral pathogens from the caecal contents of mice by anaerobic preparation

The aim of this study was to investigate methods to eliminate pathogenic viral agents while preserving the 'normalizing' properties of the gut microflora of mice. Mouse hepatitis virus A59 (MHV), Reo 3 virus and Theiler GD VII virus were added to the caecal contents of 'normal' mice and following dilution, with or without subsequent culturing, given to germ-free mice. Four weeks later antibody titres against these and other viruses were determined. MHV and Theiler CD VII virus survived dilution but were eliminated during culturing. Reo-virus survived the 10(-1) dilution-culture step. All dilutions and dilution-cultures of caecal contents resulted in 'normalization' in germ-free recipients of the relative caecal weight, percentage faecal fusiform-shaped bacteria, faecal bile acids and colonization of small intestine by segmented filamentous bacteria.

The 'normalization' of germ-free rabbits with host-specific caecal microflora.

Hysterectomy-derived germ-free rabbits were given colonization-resistant caecal flora (CRF) from mice, or microflora obtained from the caecum of an antibiotic-decontaminated conventional rabbit and compared with rabbits conventionally raised with the doe. Bodyweight and the following intestinal parameters were determined for the 3 groups: colonization resistance to E. coli, relative caecal weight, villus:crypt ratio (ileum), beta-aspartylglycine (faeces), volatile fatty acids (caecum), and bile acids (faeces). Germ-free rabbits given mouse CRF-flora showed values quite different from control animals for most parameters, indicating unsuitability of mouse CRF flora to 'normalize' rabbits. In germ-free rabbits given modified (antibiotic-treated) rabbit flora, values for most parameters were intermediate between those found for the other 2 groups. This species-specific caecal flora should be improved to provide full 'normalization' of germ-free rabbits.

The Effect of Norfloxacin and of Rosoxacin on the Colonization Resistance of the Digestive Tract in Mice

Summary Conventional mice were treated orally with various doses of norfloxacin and rosoxacin, respectively, to determine to which extent the “colonization resistance” (CR) of the digestive tract is affected. In addition, the effect was studied of both drugs on the endogenous Enterobacteriaceae and enterococci in the digestive tract (faeces). According to parameters for the CR of the digestive tract, such as the appearance of β-aspartylglycine and the relative caecal weight, norfloxacin did not decrease the CR in a dose range of up to 0.30 mg/mouse/day. A dose of 0.05 mg/mouse/day sufficed to clear the digestive tract of endogenous Enterobacteriaceae within three days. The highest dose of rosoxacin of 6.0 mg/mouse/day did not decrease the CR. A dose of 0.9 mg/mouse/day cleared the digestive tract of endogenous Enterobacteriaceae . These two drugs could therefore be considered for use in selective decontamination of the digestive tract of neutropenic patients.

Influence of temocillin on colonisation resistance and consequences for therapy.

The influence of temocillin on the colonisation resistance of the digestive tract was studied in mice, with doses ranging from 0.062 to 1 mg/day administered orally and 0.25 to 4 mg/day administered subcutaneously. The effect on the colonisation resistance was measured by the concentration of resistant bacteria (either endogenous enterococci or an exogenous strain of Enterobacter cloacae) as well as by the relative caecal weight and the appearance of beta-aspartylglycine in the caecal contents. None of these parameters indicated a decreased colonisation resistance by any of the dosages investigated, meaning that, in the mouse the drug can be used safely without an increased risk of overgrowth by resistant bacteria causing superinfections. Both systemic and oral administration of 0.25mg of temocillin/mouse/day (10 mg/kg/day) appeared to completely suppress the sensitive Gram-negative bacilli from the digestive tract within 2 days. This selective decontamination of the digestive tract in mice was the reason for a subsequent study in man. It emerged that selective decontamination with parenterally administered temocillin was possible in 7 out of 10 volunteers. The remaining 3 however, did not respond to temocillin although their faecal Gram-negative bacilli were susceptible to the drug. In none of the volunteers did the colonisation resistance appear to be affected. The consequences of the use of temocillin for either prevention or therapy of infections are discussed.

'Normalization' of germfree mice with anaerobically cultured caecal flora of 'normal' mice.

Germfree (GF) mice were inoculated with a cultured flora from 10(-1), 10(-3), 10(-5), and 10(-7) dilutions of caecal contents from a 'normal' mouse. GF mice associated with a flora of a 'normal' mouse served as controls. The following intestinal parameters were determined: Colonization resistance (CR), Relative caecal weight (RCW), villus:crypt ratio (jejunum and ileum), IgA-producing cells (jejunum and ileum), beta-aspartyl glycine (faeces), volatile and non-volatile fatty acids (caecum) and bile acids (faeces). Only the 10(-1) culture was able to induce similar changes in the GF mice to a 'normal' flora. The GF + 10(-5) and GF + 10(-7) groups deviated markedly from the controls while the GF + 10(-3) group showed in general intermediate values between GF + SPF and GF + 10(-1) on the one hand and GF + 10(-5) and GF + 10(-7) on the other hand. beta-aspartyl glycine was present only in the GF + 10(-7) group. Scanning electron microscopy (SEM) of ileal contents revealed segmented filamentous organisms in the ileum of controls and the GF + 10(-1) group. The faecal flora consisted mainly of fusiform organisms. In the faeces of the 10(-5) and 10(-7) groups increasing amounts of non-bacterial matter were found, while in the faeces of the other groups virtually only bacteria were seen.