Caecal Counts Research Articles

Crossbreeding impacts on caecal bacterial count and antibody titres in chickens

ABSTRACT 1. A crossbreeding experiment was conducted using 20 sires and 120 dams from each Fayoumi (F) and Rhode Island Red (R) breeds. The F1 chicks of ½F½R and their reciprocal ½R½F crosses were used to estimate direct, maternal and heterotic effects. 2. The caecal bacterial counts of Salmonella typhimurium and Enterococcus faecium and the IgA, IgG and IgM antibody titres were determined. Chicks of each genetic group (120 birds) were divided into three groups (40 birds per group) and chicks of the first group were assigned as the control group, while the second group was inoculated with S. typhimurium and E. faecium at 7 and 10 d of age (106 cfu/chick) and the third was inoculated with S. typhimurium at 10 d of age (106 cfu/chick). 3. The generalised least square procedure was used to estimate cross-breeding effects. The S. typhimurium counts in the R breed was highly significant, followed by ½F½R cross, ½R½F cross, and F breed. The differences among genetic groups in E. faecium counts and caecal pH was not significant. The estimates of IgA, IgG, and IgM antibody titres were highly significant in the F breed, followed by ½R½F cross, ½F½R cross, and the R breed. 4. The estimates of direct additive effects were highly significant F breed for the counts of S. typhimurium and antibody titres of IgA, IgG, and IgM. The maternal effects were highly significant F breed for S. typhimurium, E. faecium count, and antibody titres of IgA, IgG, and IgM. Estimates of direct heterosis were significant for S. typhimurium count and IgA antibody titre but not significant for E. faecium count, caecal pH, and antibody titres of IgG and IgM. 5. The results showed that the Fayoumi breed could be used in breeding programmes to improve immunity traits against S. typhimurium in chickens.

Growth performance, well-being, and gut microbial population of broilers raised in cages and floor pens under the hot and humid tropical climate

The study was carried out to compare the growth performance, gut microbiota, incidence of footpad dermatitis (FPD), leg weakness, physiological, and immunological responses in broilers kept in cage (CS) and floor pen (FS) rearing systems under a tropical environment. One-day-old male Cobb 500 chicks were allocated to either three-tiered wire-floored battery cages or floor pens with wood shavings. The body weight on day 42 and feed intake from days 1 to 42 of caged chickens were lower than those of chickens reared in floor pens. However, the caged chickens had significantly better overall (days 1–42) feed conversion ratios than those on floor pens. The FS system was detrimental to the incidence of FPD. The FS birds showed higher and lower caecal counts of Escherichia coli and Salmonellae, respectively than the CS birds. The FS birds had longer durations of latency-to-lie than their caged counterparts, which suggested that the former had a lower incidence of leg weakness. Higher serum basal concentrations of corticosterone, ovotransferrin and ceruloplasmin were noted in the FS chickens compared to the CS group. Antibody titre against Newcastle disease vaccinations was not affected by the rearing system. In conclusion, the cage rearing system appeared to benefit performance, the incidence of FPD, physiological response, fear reactions, and intestinal population of E. coli in broiler chickens under the hot and humid tropical conditions. However, raising broilers on floor pens improves body weight and leg strength, and reduces the caecal Salmonellae population compared to caged broilers. HIGHLIGHTS Caged broilers have better feed efficiency and lower caecal Escherichia coli population and incidence of food-pad dermatitis than those on floor pens. Raising broilers on floor pens improves body weight and leg strength, and reduces the caecal Salmonellae population compared to caged broilers. Broilers on floor pens are more physiologically distressed than their caged counterparts.

Polymorphic characterisation of gallinacin candidate genes and their molecular associations with growth and immunity traits in chickens

ABSTRACT 1.Four gallinacin (GAL) genes were assessed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) to characterise these genes in Fayoumi (F) and Rhode Island Red (R) breeds and their crosses of Rhode Island Red × Fayoumi (½R½F) and Fayoumi × Rhode Island Red (½F½R). 2.Genes examined were GAL2, GAL3, GAL4 and GAL5. The molecular associations between the SNPs of the gallinacin genes and body weight, caecal bacterial count and the serum antibody titres of IgA, IgG and IgM were determined. In the R breed, the frequency of TC genotype was higher than TT and CC genotypes for the GAL3 gene. The GG genotype frequency was higher than AA and AG genotypes for the GAL4 gene in the other genetic groups, and the CA genotype frequency was higher than CC and AA genotypes in crosses for the GAL5 gene. 3.In all populations, the frequency of the C allele was higher than the T allele for the GAL3 gene, the G allele was higher than the A allele for the GAL4 gene and the C allele was higher than the A allele for the GAL5 gene. The observed heterozygosity in R, ½R½F and ½F½R was 0.476, 0.375 and 0.158 for the GAL3 gene, 0.458, 0.615 and 0.250 for the GAL4 gene and 0.053, 0.792 and 0.739 for the GAL5 gene, while the expected heterozygosities were 0.490, 0.430 and 0.145 for the GAL3 gene, 0.430, 0.348 and 0.219 for the GAL4 gene and 0.229, 0.478 and 0.496 for the GAL5 gene, respectively. 4.On a molecular level, the genotype TT was significantly higher for body weight than TC and CC genotypes in the GAL3 gene. Birds with the GG genotype had a significantly lower Salmonella typhimurium count than birds with AA genotype in the GAL4 gene. Birds with the genotype AA had higher significant body weights than those with CC and CA genotypes in the GAL5 gene. 5.The results indicated that the GAL3, GAL4 and GAL5 genes are potential candidates for selection programmes to improve S. typhimurium resistance and body weight in chickens.

The Effect of Whey on Performance, Gut Health and Bone Morphology Parameters in Broiler Chicks.

Whey is a highly nutritious byproduct of the cheese industry that can be used effectively in the animal feed industry. However, the use of whey in poultry diets is limited by its high lactose and mineral contents. The objective of the present study was to evaluate the effect of different concentrations of whey in poultry diets on the performance, intestinal microbiota and physico-chemical parameters of the intestinal ecosystem, as well as on the bone morphology and its strength in broiler chicks. One hundred and twenty-eight, day-old, male broiler chicks were randomly allocated into four treatment groups of 32 chicks each. The treatment groups were: group A, which served as negative control and groups B, C and D, supplemented with 1, 2 and 5% of dietary whey, respectively. Performance of the groups was evaluated throughout the experiment. Following necropsies, the gastrointestinal tract from each bird was removed, divided into its anatomical parts and intestinal samples were taken for microbiological analysis and for pH and viscosity measurement as well. Tibiotarsus was also collected for morphometric analysis and strength evaluation. The statistical analysis of the experimental data revealed that the dietary supplementation of 1 and 2% of whey improved significantly (p ≤ 0.05) the body weight, while the addition of 5% of whey reduced significantly (p ≤ 0.05) the body weight. Furthermore, the addition of 1, 2 and 5% of dietary whey increased significantly (p ≤ 0.05) the pH of jejunum digesta and reduced significantly (p ≤ 0.05) the pH of caecum digesta compared to the control group. The addition of 1 and 2% of whey reduced significantly (p ≤ 0.05) the viscosity in the jejunum and ileum digesta, compared to the addition of 5% of whey which reduced significantly (p ≤ 0.05) the viscosity in jejunum digesta but increased significantly (p ≤ 0.05) the viscosity in ileum digesta. Moreover, the addition of 1, 2 and 5% of dietary whey increased significantly (p ≤ 0.05) the caecal counts of Lactobacillus spp. and Lactococcus lactis, while the addition of 5% of whey reduced significantly (p ≤ 0.05) the tibiotarsus length. It can be concluded that the addition of low quantities of whey up to 2% promoted the performance and gut health of birds, while the addition of higher quantities of whey at the level of 5% had a detrimental effect on the performance and tibiotarsus length.

Over-processed meat and bone meal and phytase effects on broilers challenged with subclinical necrotic enteritis: Part 1. Performance, intestinal lesions and pH, bacterial counts and apparent ileal digestibility.

This feeding study investigated the hypothesis that over-processing of meat and bone meal (MBM) would impair the performance, gut health and ileal digestibility of nutrients in birds challenged with necrotic enteritis (NE). The effect of phytase (500 vs. 5,000 FTU/kg) was also examined using manufacturers recommended matrix values for 500 FTU for both levels. Ross 308 male broilers (n = 768) were assigned to 8 diets, with 6 replicate pens per diet and 16 birds per replicate pen using a randomized design with a factorial arrangement of treatments. Factors were NE challenge (no or yes), MBM (as received or over-processed), and phytase level (500 or 5,000 FTU/kg). Half of the birds were challenged with 5,000 oocysts of field strains of Eimeria acervulina and Eimeria brunetti, and 2,500 oocysts of Eimeria maxima on d 9 and 108 CFU/mL of Clostridium perfringens strain EHE-NE18 on d 14 and 15 post-hatch. Challenge × MBM interactions were detected for weight gain (WG), feed conversion ratio (FCR) and feed intake (FI) at d 14, 21 and 28, showing that challenged birds fed over-processed MBM had decreased WG (P < 0.05) and FI (P < 0.05) at d 14, increased FCR (P < 0.05) at d 21 and decreased WG (P < 0.05) and FI (P > 0.05) at d 28. Birds fed low phytase had increased livability (P < 0.05) at d 42. The challenge increased the prevalence and severity of NE induced lesions in the jejunum (P < 0.05) and ileum (P < 0.05). The birds fed over-processed MBM had decreased pH in the jejunum (P < 0.05) and ileum (P < 0.05) at d 16. High phytase increased apparent ileal digestibility (AID) of Ca (P < 0.05) and P (P < 0.05), and over-processed MBM increased AID of carbon (C; P < 0.05) and Ca (P < 0.05) at d 29. The challenge increased the caecal counts of Lactobacillus spp. (P < 0.05) and C. perfringens (P < 0.05) at d 16. The results indicated that supplementation of diets with high phytase reduces the negative impact on performance from over-processed MBM during NE as a result of increased nutrient digestibility.

Performance, gut morphology and microbiology effects of a Bacillus probiotic, avilamycin and their combination in mixed grain broiler diets

ABSTRACT1. This study aimed to determine the effect of avilamycin (AGP) and a multi-strain Bacillus probiotic (DFM) on the performance, gut histology and microbiology of broilers fed on a mixed grain diet.2. A total of 800 chicks were allocated to four treatments: a control diet, control+AGP, control+DFM, or control+AGP+DFM. Bodyweight, feed intake and FCR were measured at d 0, 21 and 42. Samples were taken at d42 to determine villus height (VH), crypt depth (CD) and ratio (VH:CD). Mucosal E. coli and Lactobacilli counts were measured at d42.3. At d42, DFM and AGP+DFM significantly increased weight over the control, with AGP returning an intermediate value. FCR followed a similar pattern. DFM and AGP+DFM significantly increased VH and CD in all gut sections compared to the control.4. DFM and AGP+DFM reduced E. coli counts compared to control, with AGP reducing caecal counts only, while Lactobacilli counts were increased.5. Divergent histology and microbiology between treatments highlight the different modes of action of AGP and DFM for improving broiler growth and feed efficiency.

Effects of dietary mixture of garlic (Allium sativum), coriander (Coriandrum sativum) and probiotics on immune responses and caecal counts in young laying hens

This study was conducted to evaluate the effects of a combined mixture of phytogenic extracts (garlic and coriander) and probiotics on growth performance and immune responses in laying hens based on the results of invitro studies to screen for immunomodulatory potency of each ingredient. Several parameters of immunomodulatory potency were estimated using lamina propria leucocytes (LPLs) isolated from rat intestinal mucosa tissue. Results show that the combined mixture enhanced LPLs proliferation, increased LPL-mediated cytotoxicity against YAC-1 tumour cells, and decreased lipopolysaccharide (LPS)-induced cytokine production including tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in LPLs. For invivo study, laying hens (n=50/each diet group) were fed with control diet, a diet containing antibiotics (0.01% per kg feed) or the combined mixture (0.02% per kg feed) for 21days. The dietary combined mixture improved egg production (p<0.05) but not growth performance and carcass traits. Interestingly, the patterns of suppressing plasma IFN-γ productions during inflammation by LPS injection and decreasing caecal E.coli counts in the combined mixture group were comparable to those in the antibiotics group. Taken together, our results suggested that the 0.02% of combined mixture of phytogenic extracts and probiotics as ingredients has potential immunomodulatory effects in laying hens.

The antimicrobial peptide sublancin ameliorates necrotic enteritis induced by Clostridium perfringens in broilers12

Sublancin is an antimicrobial peptide produced by 168 containing 37 amino acids. The objective of this study was to investigate its inhibitory efficacy against both in vitro and in vivo. In the in vitro study, we determined that sublancin had a minimum inhibitory concentration of 8 μM against , which was much higher than the antibiotic lincomycin (0.281 μM). Scanning electron microscopy showed that sublancin damaged the morphology of . The in vivo study was conducted on broilers for a 28-d period using a completely randomized design. A total of 252 chickens at 1 d of age were randomly assigned to 1 of 6 treatments including an uninfected control; an infected control; 3 infected groups supplemented with sublancin at 2.88, 5.76, or 11.52 mg activity/L of water; and an infected group supplemented with lincomycin at 75 mg activity/L of water (positive control). Necrotic enteritis was induced in the broilers by oral inoculation of on d 15 through 21. Thereafter, the sublancin or lincomycin were administered fresh daily for a period of 7 days. The challenge resulted in a significant decrease in ADG ( < 0.05) and a remarkable deterioration in G:F ( < 0.05) during d 15 to 21 of the experiment. There was a sharp increase of numbers in the cecum ( < 0.05). The addition of sublancin or lincomycin reduced caecal counts ( < 0.05). The counts had a tendency to decrease in the lincomycin treatment ( = 0.051) but were the highest in the sublancin treatment (5.76 mg activity/L of water). A higher villus height to crypt depth ratio in the duodenum and jejunum as well as a higher villus height in the duodenum were observed in broilers treated with sublancin or lincomycin ( < 0.05) compared with infected control broilers. It was observed that sublancin and lincomycin decreased IL-1β, IL-6, and tumor necrosis factor-α levels ( < 0.05) in the ileum compared with the infected control. In conclusion, although sublancin's minimum inhibitory concentration is much higher than lincomycin in vitro, less sublancin is needed to control necrotic enteritis induced by in vivo than lincomycin. These novel findings indicate that sublancin could be used as a potential antimicrobial agent to control necrotic enteritis.

Chicken Caecal Microbiome Modifications Induced by Campylobacter jejuni Colonization and by a Non-Antibiotic Feed Additive.

Campylobacter jejuni is an important zoonotic foodborne pathogen causing acute gastroenteritis in humans. Chickens are often colonized at very high numbers by C. jejuni, up to 109 CFU per gram of caecal content, with no detrimental effects on their health. Farm control strategies are being developed to lower the C. jejuni contamination of chicken food products in an effort to reduce human campylobacteriosis incidence. It is believed that intestinal microbiome composition may affect gut colonization by such undesirable bacteria but, although the chicken microbiome is being increasingly characterized, information is lacking on the factors affecting its modulation, especially by foodborne pathogens. This study monitored the effects of C. jejuni chicken caecal colonization on the chicken microbiome in healthy chickens. It also evaluated the capacity of a feed additive to affect caecal bacterial populations and to lower C. jejuni colonization. From day-0, chickens received or not a microencapsulated feed additive and were inoculated or not with C. jejuni at 14 days of age. Fresh caecal content was harvested at 35 days of age. The caecal microbiome was characterized by real time quantitative PCR and Ion Torrent sequencing. We observed that the feed additive lowered C. jejuni caecal count by 0.7 log (p<0.05). Alpha-diversity of the caecal microbiome was not affected by C. jejuni colonization or by the feed additive. C. jejuni colonization modified the caecal beta-diversity while the feed additive did not. We observed that C. jejuni colonization was associated with an increase of Bifidobacterium and affected Clostridia and Mollicutes relative abundances. The feed additive was associated with a lower Streptococcus relative abundance. The caecal microbiome remained relatively unchanged despite high C. jejuni colonization. The feed additive was efficient in lowering C. jejuni colonization while not disturbing the caecal microbiome.

An investigation of broiler caecalCampylobactercounts at first and second thinning

The objectives of this study were the following: (i) to investigate if Campylobacter negative flocks at first thinning remain negative at second thinning; (ii) to determine if the caecal counts in birds infected during first thinning remain lower than in birds that were positive at first thinning; and (iii) to determine if reducing the time between first and second thinning to a maximum of 4 days would reduce both the incidence and prevalence of broiler caecal contamination. Twenty-two flocks were tested at first and second thinning using ISO methodologies. Of the 14 that had a 4-day duration between first and second thinning, nine flocks were Campylobacter negative at first thinning. By second thinning, all 14 flocks were positive and Campylobacter counts ranged from 5·5 to 6·6 log(10) CFU g(-1) regardless of the status at first thinning. The other eight flocks were all Campylobacter positive at first thinning with counts ranging from 0·8 to 6·1 log(10) CFU g(-1) which increased to 5·1 to 6·9 log(10) CFU g(-1) by second thinning (3-10 days). PCR speciation and MLST genotyping suggested the majority of isolates were Camp. jejuni belonging to STs 257, 814, 6763 and 6764. It was concluded that; thinning introduces Campylobacter into broiler flocks; caecal counts in birds at second thinning are similar, regardless of flock status at first thinning and reducing the time between first and second thinning to a maximum of 4 days is not an effective control strategy. This study informs Campylobacter control strategy at primary production, suggesting all post-first thinning broilers should be treated as 'high risk' regardless of Campylobacter status at first thinning or duration between first and second thinning.

Development of a feed additive to reduce caecal Campylobacter jejuni in broilers at slaughter age: from in vitro to in vivo , a proof of concept

In vitro and in vivo challenge studies were undertaken to develop an in-feed additive of microencapsulated propionic, sorbic acids and pure botanicals to control Campylobacter jejuni in broilers at slaughter age. Organic acids (OA) and pure botanicals were tested in vitro against Camp. jejuni, whereas in vivo, chickens were fed either a control diet, or increasing doses of the additive for 42 days (experiment 1); in the second experiment, chickens received the additive at 0.1 or 0.3% from day 0 to 21 or from day 22 to 42. The additive consistently reduced Camp. jejuni caecal counts at any given dose (exp. 1) or inclusion plan (exp. 2). Moreover, it was able to reduce the number of goblet cells and modify mucin glycoconjugates biosynthesis pattern. We developed an additive that was effective in reducing Camp. jejuni in slaughter-age chickens even at low doses (0.1%). That efficacy was the result of the synergistic action between OA and botanicals. This study provides a strategy to reduce Camp. jejuni in broilers and, as a consequence, to improve the safety of the food chain. Moreover, data suggest that a treatment limited to the last weeks before slaughter would allow to save on inclusion of the additive throughout the whole production cycle.

Effect of yeast with bacteriocin from rumen bacteria on growth performance, caecal flora, caecal fermentation and immunity function of broiler chicks

SUMMARYThe aim of the current study was to investigate the effects of bacteriocin ofRuminococcus albus7 that is expressed by yeast on growth performance, caecal flora, caecal fermentation and immunity function of broilers. A total of 180, one-day-old healthy broiler chicks were randomly divided into three groups: control, bacteriocin (2·5 g/kg feed) and nosiheptide (NHT) (2·5 mg/kg, as antibiotic control). Growth performance, caecal flora, caecal fermentation products and immunoglobulin (Ig) concentration were determined when chicks were 21 and 35 days old. The gene expression of avianβ-defensin (AvBD) and mucin (MUC2) were measured at 35 days old. The supplementation of bacteriocin and NHT had no significant effect on body weight gain (BWG) during the experimental period. Bacteriocin supplementation significantly enhanced the growth ofLactobacillus(P&lt;0·05) and resulted in higher lactate concentration (P&lt;0·01) in broiler caeca at 21 days old. Both bacteriocin and NHT supplementation resulted in lowerEscherichia coil(P=0·072) andEnterococcus(P=0·038) counts than in the control group at 35 days old. The bacteriocin treatment group tended to increase bile IgA and showed higher bile IgA than the NHT treatment group (P=0·059) at 35 days old. Higher levels of AvBD1, AvBD4 and MUC2 gene expression were observed in the NHT treatment group (P&lt;0·05), but expression of AvBD9 was significantly decreased in both bacteriocin and NHT treatment groups (P&lt;0·05). In conclusion, bacteriocin supplementation elevated the caecalLactobacilluscounts and affected the immunity function. These benefits suggested that bacteriocin supplementation could be a potential alternative to antibiotics in broiler feed.

The ability of green tea to positively modulate key markers of gastrointestinal function in rats

The beneficial effects of selenium-containing green tea (Se-GTE, 1.44 mg selenium/kg dry leaves) and China green tea (CH-GTE, 0.13 mg selenium/kg leaves) on the population size of lactobacilli and bifidobacteria and the activity of two microbial enzymes in the caeca of rats have been investigated. Oral gavage of rats with Se-GTE extract for 6 days resulted in a significant increase in caecal counts of lactobacilli and bifidobacteria (p < 0.05) while significantly reducing the caecal counts of bacteroides and clostridial bacteria. In contrast, gavaging the rats with CH-GTE extract for 6 days resulted in a slight but not significant increase in the numbers of caecal lactobacilli and bifidobacteria but decreased significantly the numbers of bacteroides (p < 0.05) and clostridia (p < 0.05). In addition, rats gavaged with CH-GTE and Se-GTE showed a 17.2% and 21.3% reduction in the activity of the bacterial enzyme β-glucuronidase, respectively, when compared with the rats gavaged with water only. β-glucuronidase is considered to be one of the enzymes that increases the risk for colorectal cancer. Moreover, gavaging rats with these teas resulted in 19% and 25.5% increments in the activity of β-glucosidase, respectively. In conclusion, Se-GTE showed both bifidogenic and lactogenic effects and the high level of selenium may be behind the superiority of this tea over CH-GTE.

Influence of age at weaning and nutritive value of weaning diet on growth performance and caecal traits in rabbits

To investigate the relationship between dietary nutrient concentration and weaning age on growth performance and caecal characteristics of rabbits, a trial was carried out on 64 litters (eight rabbits/litter) comparing two weaning ages (25 vs. 34 d) and two diets (HC: high concentrated and LC: low concentrated diet) offered to the kits from 18 to 34 d of age. At 34 d of age 54 animals per group were caged individually and all were fed the LC diet until 45 d of age. All animals were then fed a standard fattening diet (37% neutral detergent fiber, 3.4% ether extract and 18.0% crude protein on dry matter basis) until slaughter at 80 d. The digestibility trial was performed from 56 to 60 d of age on another group of 16 rabbits (8 per diet). During the experimental period (18-80 d of age), feed intake and animal weights were recorded. Caecal volatile fatty acids were measured at 45 and 80 d of age, while microbiological analysis was performed at 25 and 34 d on healthy suckling rabbits. Digestibility of dry matter, protein, neutral detergent fiber, fat and energy was higher in rabbits fed the HC diet (by 7.7, 7.4, 13.1, 26.7, 10.6%, respectively; P&lt;0.001) than in those fed the LC diet. Growth rate and feed conversion ratio (FCR) from 18 to 34 d improved by 7.7 and 9.5% in rabbits fed HC in comparison to the LC diet, respectively (P?0.061). Diet offered around weaning did not influence growth rate or FCR from 34 to 80 d of age. Rabbits weaned earlier increased feed intake (by 67.8%) from 25 to 34 d, but reduced growth rate (by 26.8%) compared to animals weaned at 34 d (P&lt;0.001). Early weaning reduced live weight during the entire fattening period (P?0.018), as well as the FCR (by 4%; P&lt;0.001). Caecal pH was lower at 45 d of age in rabbits weaned at 25 d than in those weaned at 34 d (5.53 vs. 5.83; P=0.019). Treatments did not affect total caecal VFA concentration, but HC diet decreased caecal acetic concentration and increased butyric acid level compared to the LC diet at 45 d (P?0.001). HC diet tended to reduce caecal counts of Enterobacteriacae (P=0.093), while it did not affect facultative anaerobic bacteria, E. Coli and Costridium spp. The LC diet increased at 25 d the number of Clostridium perfringens in comparison with the HC group at the same age and in comparison with animals fed both two diets at 34 d (P&lt;0.001). The values of E. Coli and Enterobacteriaceae increased (P?0.008) from 25 to 34 d of age, whereas that of Clostridium spp. decreased. Weaning at 25 d increased mortality from 18 to 34 d compared with rabbits weaned at 34 d (7.02 vs. 2.46%, P=0.017). However, during the fattening period (34-80 d) rabbits weaned earlier showed lower mortality (7.41 vs. 17.6%; P=0.024).

Effect of tannins on growth performance and intestinal ecosystem in weaned piglets

Tannins are natural polyphenolic compounds that can reduce digestibility of dietary protein but also display antibacterial effects. The present study investigated, in vitro and in vivo, the effect of different levels of tannins (using a chestnut wood extract containing 75% tannins) on growth performance, intestinal microbiota and wall morphology in piglets. During a 24 h in vitro caecal fermentation, the utilisation of tannins at 0.75, 1.5, 3, and 6 g/l significantly reduced total gas production and concentrations of ammonia and volatile fatty acids and increased viable counts of enterococci and coliforms. When fed to piglets at 1.13, 2.25, and 4.5 g/kg, tannins significantly improved feed efficiency and reduced caecal concentrations of ammonia, iso-butyric, and iso-valeric acid. Viable counts of lactobacilli tended to be increased by tannins in the jejunum, while bacterial caecal counts were not affected. Depth of ileal crypts tended to decrease in piglets fed tannins at 2.25 and 4.5 g/kg. The present study showed that feeding weaned piglets with a tannin-rich wood extract can result in improved feed efficiency and reduction of intestinal bacterial proteolytic reactions. The growth-enhancing effect that tannins had on enterococci and coliforms under in vitro conditions deserves further investigation.

Dietary level of fibre and age at weaning affect the proliferation of Clostridium perfringens in the caecum, the incidence of Epizootic Rabbit Enteropathy and the performance of fattening rabbits

An experiment was conducted to investigate the effects of dietary fibre content and weaning age on Clostridium perfringens proliferation in the caecum and fattening mortality in growing rabbits farmed in a facility having Epizootic Rabbit Enteropathy. The experiment consisted in a 2 × 2 factorial arrangement with two weaning ages (28 days vs. 42 days) and two levels of dietary neutral detergent fibre assayed with a heat stable amylase and expressed exclusive of residual ash (aNDFom; 330 g/kg vs. 425 g/kg). Controls were made during two consecutive experimental periods that differed in hygienic environmental conditions by modifying the intensity of cleaning and disinfection in the farm previous to the trial. An interaction (P<0.001) was detected among the independent variables studied on Cl. perfringens enumeration in the caecal contents, as minimal values for this trait were obtained in non-medicated animals reared in a clean environment, and especially when they were weaned at a later age and fed the diet with the lower fibre content. The treatments studied also led to a variation in fattening mortality (from 4.7% to 34.0%), which was highly and positively correlated (P<0.001) to the average Cl. perfringens caecal counts in each combination of treatments. The results of the current study indicate that high counts of Cl. perfringens in the caecum can be used as an indicator of Epizootic Rabbit Enteropathy, and suggest that strategies designed to control its proliferation in the caecum might help to limit fattening mortality in rabbit fed diets not-medicated with antibiotics.

Influence of fermentable carbohydrates on the intestinal bacteria and enteropathogens in broilers

The gastrointestinal tract is a complex milieu as a result of interaction between dietary ingredients and the intestinal bacteria. Following the European ban on the use of in-feed antibiotics, research has focused mainly on the potentially beneficial activities of the intestinal microbiota. Fermentable carbohydrates, or ‘prebiotics’, such as non-digestible oligosaccharides, are considered to have beneficial effects on the composition and activity of the indigenous microbiota, which can enhance the resistance of the host against colonisation of pathogenic bacteria in the GIT. Only a limited number of prebiotics has been tested in broilers that include fructo-oligosaccharides, inulin, mannan-oligosaccharides, alpha gluco-oligosaccharides, isomalto-oligosaccharides, different kestoses and lactose along with its derivatives. This review provides an overview pertaining to the potential impact of prebiotics on the intestinal bacterial population in broilers and summarizes the data regarding the role of prebiotics in preventing the colonisation of enteropathogens especially Salmonella spp., Campylobacter spp. and Clostridium spp. Moreover, the influence of prebiotics on the intestinal bacterial fermentation profile, particularly short chain fatty acids, ammonia and lactate, is also discussed. Prebiotics have been found to affect the intestinal bacterial population particularly elevating the caecal count of Lactobacillus spp. and Bifidobacterium spp. The effect of prebiotics on the intestinal bacteria is also evident in terms of change in the total concentration or relative proportion of short chain fatty acids. The ability of prebiotics in controlling the colonisation of different enterpathogens especially Salmonella spp., Clostridium perfringens or Campylobacter spp. showed inconsistent results depending upon the available literature.

Intestinal colonization with bifidobacteria affects the expression of galectins in extraintestinal organs

This study aimed at determining the contribution of intestinal bifidobacteria to the immune system activation using widely distributed galectins as markers of immune cell homoeostasis. In human flora-associated mice, bacteria were enumerated in the gut, blood, spleen, liver and lungs, while the expression of galectin-1 (Gal-1) and galectin-3 (Gal-3) was estimated by PCR in the intestine and real-time quantitative PCR in the other organs. Gal-1 and -3 were rarely expressed in the intestine. In blood, only Gal-1 was expressed while both galectins were expressed in all other organs. A high prevalence of colonic bifidobacteria was associated with a lower expression of both pulmonary galectins, whose levels negatively correlated with bifidobacterial counts. Caecal bifidobacterial counts also negatively correlated with pulmonary Gal-3 mRNA levels. The spleen was the only organ showing an upregulation of Gal-1 expression related to its bacterial contamination. However, this upregulation was only observed when bifidobacteria were not detected in the colon. A putative mechanism explaining the reduced expression of galectins when bifidobacteria highly colonize the mouse intestine could be that, by reducing the bacterial translocation, bifidobacteria also lead to a decreased blood concentration of substances produced by intestinal bacteria.

Blueberry husks and multi-strain probiotics affect colonic fermentation in rats

The aim was to investigate how blueberry husks and/or mixtures of probiotic strains (Lactobacillus crispatus DSM16743, L. gasseri DSM16737 and L. plantarum DSM15313 (LABmix), or Bifidobacterium infantis DSM15159 and DSM15161 (BIFmix)) affect colonic fermentation, caecal counts of lactobacilli, bifidobacteria and Enterobacteriaceae, body weight gain, and blood concentrations of carboxylic acids (CA) and ammonia in rats. Dietary fibres in blueberry husks were fermented to 61 % in colon, and the elevated faecal excretion of fibre and protein contributed to the high faecal bulking capacity (1.3). The caecal pool of CA was higher in rats fed blueberry husks than the fibre-free control (P < 0.05), and the propionic acid proportion was higher in the distal colon than in the control group (P < 0.05). Probiotics lowered the caecal amount of CA when added to blueberry husks (P < 0.001), while the propionic acid proportion was higher with LABmix (P < 0.01) than blueberry husks only. The propionic acid and butyric acid concentrations in blood were higher in rats fed blueberry husks and probiotics than those fed blueberry husks only (P < 0.01), implying that the absorption of these acids was facilitated by the bacteria. The caecal counts of lactobacilli, bifidobacteria and Enterobacteriaceae were lower in rats fed blueberry husks than the control diet (P < 0.05). The body weight gain was partly influenced by the caecal tissue and contents weights, and BIFmix decreased the ammonia concentration in blood (P < 0.05). We conclude that colonic fermentation is differentially affected by dietary fibre and probiotics, which may be of importance when developing foods with certain health effects.

The change of intestinal microecology in rats after orthotopic liver transplantation

To investigate the intestinal microflora status and bacterial translocation in rats after liver transplantation. Male Brown-Norway (BN) rats were randomly divided into 4 groups: group I (n = 8) for liver transplantation; group II (n = 8) for simulated liver transplantation; group III (n = 8) for sham operation and group IV (n = 8) for normal group. Caecal bacterial counts, plasma endotoxin, intestinal mucosal ultrastructure and bacterial translocation to liver, spleen, kidney, and mesenteric lymph node were studied 24 h after surgery. The numbers of Bifidobacterium and Lactobacillus per gram of wet feces were significantly decreased in group I compare with those in the group III and group IV, while Enterobacteriaceae and Enterococcus counts were increased markedly compare with those in the group III and group IV, but no different was found between group I and group II. Impaired intestinal mucosa integrity were found in the group I and group II. In group I, the levels of plasma endotoxin increased after the transplantation when compare with group III and group IV. Increased incidence of bacterial translocation to liver, spleen and mesenteric lymph node were also observed after the transplantation (compare with those in the group IV, P < 0.01; compare with those in the group III, P < 0.01, P < 0.01, P < 0.05, separately). The increased rate of the bacterial translocation in liver was also found in transplantation group as compare with group II (P < 0.05). Liver transplantation may lead to disturbance of intestinal microflora and impairment of intestinal mucosal barrier function, and this dysfunction might be caused by the process of intestinal ischemia-reperfusion injury in transplantation.