Influence of the implantation of Lactobacillus acidophilus in chicks on the growth, feed conversion, malabsorption of fats syndrome and intestinal flora

The effect of Bacillus subtilis and its delivery route on hatch and growth performance, blood biochemistry, immune status, gut morphology, and microbiota of broiler chickens

This study evaluated the effect of probiotics (Bacillus subtilis fermentation extract) and its delivery route (in-feed or in ovo) on hatch and growth performance, blood biochemistry, immune status, gut morphology, and microbiota of broiler chickens. Hatching eggs were incubated for 21 d. On d 12, viable eggs were randomly allotted to 4 groups: the noninjected, in ovo saline (S), in ovo Bacillus subtilis 1 (P1), and in ovo Bacillus subtilis 2 (P2). On d 18, S, P1, and P2 groups received 0.2 mL saline diluent, 10 × 10⁶, and 20 × 10⁶ CFU of the bacterium via the amnion, respectively. At hatch, chicks were re-allotted to 5 new treatment groups: P1, P2, 0.005% in-feed Bacillus subtilis extract (P3), 0.05% in-feed bacitracin methylene disalicylate (BMD,), and corn-wheat-soybean diet negative control (NC) in 9 replicate pens (22 birds/pen) and raised for 35 d. Hatch parameters were assessed on d 0, and growth performance indices measured weekly. On d 25, 1 bird/cage was euthanized, and samples collected for further analysis. Data were analyzed by generalized linear model. Treatments S and P2 recorded higher (P = 0.01) chick BW/ Egg Weight values compared to the non-injected eggs. P3 and P2 reduced (P = 0.02) FI at week 5 compared to the NC treatment. However, no change in average body weight gain (ABG) and feed conversion ratio (FCR) were observed during the same period. At d 35, while BMD treatment showed a tendency (P = 0.09) to increase FI compared to the NC treatment, ABG and FCR were similar for all treatments. Blood sodium and chloride levels were increased (P < 0.05) by the BMD treatment compared to the NC treatment. Compared to other treatments, BMD and P3 treatments increased (P < 0.001) jejunal and ileal villus height to crypt depth ratios, respectively. However, P1 and P2 increased (P < 0.001) villus height to crypt depth ratio in the duodenum compared to NC treatment. Treatments did not affect gut microbial diversity; however, BMD treatment increased (P < 0.05) the proportion of bacteria in the genus Enterococcus in the ileum and reduced (P < 0.05) the proportion of bacteria in the genus Streptococcus in the ceca. All probiotics treatments (irrespective of route and dose) reduced (P < 0.001) the levels of serum IgG compared to the NC treatment. However, P1 and P2 had the lowest numerical decrease in serum IgG concentrations, suggesting that Bacillus subtilis (especially in ovo delivered) might provide broiler chickens with better immunological protection by neutralizing pathogenic organisms that could result in the production of natural antibodies.

Coccidia-Microbiota Interactions and Their Effects on the Host

As a common parasitic disease in animals, coccidiosis substantially affects the health of the host, even in the absence of clinical symptoms and intestinal tract colonization. Gut microbiota is an important part of organisms and is closely related to the parasite and host. Parasitic infections often have adverse effects on the host, and their pathogenic effects are related to the parasite species, parasitic site and host-parasite interactions. Coccidia-microbiota-host interactions represent a complex network in which changes in one link may affect the other two factors. Furthermore, coccidia-microbiota interactions are not well understood and require further research. Here, we discuss the mechanisms by which coccidia interact directly or indirectly with the gut microbiota and the effects on the host. Understanding the mechanisms underlying coccidia-microbiota-host interactions is important to identify new probiotic strategies for the prevention and control of coccidiosis.

The Use of Probiotics in the Reduction of Campylobacter spp. Prevalence in Poultry

Campylobacter spp. are widely distributed microorganisms, many of which are commensals of gastrointestinal tract in multiple animal species, including poultry. Most commonly detected are C. jejuni and C. coli. Although infections are usually asymptomatic in poultry, poultry meat and products represent main sources of infection with these bacteria to humans. According to recent EFSA report, campylobacteriosis is the most commonly reported zoonotic disease. In 2018, EFSA Panel on Biological Hazards indicated that use of feed and water additives is the second most likely strategy that can be successful in minimizing Campylobacter spp. colonization rate in broiler chickens. One of those feed and water additives are probiotics. From numerous research papers it can be concluded that probiotics exhibit plenty of mechanisms of anti-Campylobacter activity, which were evaluated under in vitro conditions. These results, to some extent, can explain the efficacy of probiotics in in vivo studies, although different outcome can be observed under these two laboratory conditions. Probiotics are capable of reducing Campylobacter spp. population count in poultry gastrointestinal tract and they can reduce carcass contamination. Potential modes of anti-Campylobacter activity of probiotics, results of in vivo studies and studies performed at a farm level are widely discussed in the paper.

Effects of in ovo probiotic administration on the incidence of avian pathogenic Escherichia coli in broilers and an evaluation on its virulence and antimicrobial resistance properties

Avian pathogenic Escherichia coli (APEC) causes colibacillosis in poultry, which has been traditionally controlled by the prophylactic in-feed supplementation of antibiotics. However, antibiotics are being removed from poultry diets owing to the emergence of multidrug-resistant (MDR) bacteria. Therefore, alternatives to control APEC are required. This study aimed to evaluate the effects of in ovo inoculation of probiotics on the incidence of APEC in broilers and evaluate the virulence and antimicrobial resistance properties of the APEC isolates. On embryonic day 18, 4 in ovo treatments (T) were applied: T1 (Marek's vaccine [MV]), T2 (MV and Lactobacillus animalis), T3 (MV and Lactobacillus reuteri), and T4 (MV and Lactobacillus rhamnosus). A total of 180 male broilers per treatment were randomly placed in 10 pens. The heart, liver, spleen, and yolk sac were collected on day 0, 14, 28, and 42. Presumptive E. coli isolates were confirmed by real-time PCR. The positive isolates were screened for the APEC-related genes (iroN, ompT, hlyF, iss, and iutA), and E. coli isolates containing one or more of these genes were identified as APEC-like strains. A total of 144 APEC-like isolates were isolated from 548 organ samples. No differences (P > 0.05) among treatments were observed for the incidence of APEC-like strains in all organs when averaged over sampling days. However, when averaged over treatments, the incidence in the heart, liver, and yolk sac was different among sampling days; a significant increase was observed in these organs on day 14 compared with day 0. Twenty-five antimicrobial resistance genes were evaluated for all APEC-like isolates, and 92.4% of the isolates carried at least one antimicrobial resistance gene. Thirty-seven isolates were then selected for antimicrobial susceptibility testing; MDR strains accounted for 37.8% of the isolates. In conclusion, the in ovo inoculation of a single probiotic strain did not confer protection against APEC strains in broilers. The high prevalence of MDR isolates indicates that further research on antibiotic alternatives is required to prevent APEC infections in broilers.

Xylanase and Direct-Fed Microbials (DFM) Potential for Improvement of Live Performance, Energy Digestibility, and Reduction of Environmental Microbial Load of Broilers

The challenge of identifying alternatives to subtherapeutic levels of antibiotic growth promoters (AGP) in animal feed has led to increased interest in feed additives such as exogenous enzymes and direct-fed microbials (DFM). Six corn soy-based dietary treatments were designed to investigate the effect of high-efficiency xylanase alone, Bacillus spp. probiotics alone, and their combination vs. a commonly used antibiotic growth promoter (bacitracin methylene disalicylate; BMD) on live performance and environmental Clostridium perfringens load of broiler chickens with eight replicate pens per treatment. Diets were as follows: standard diet (positive control; PC); 130 kcal/kg reduced-energy diet (negative control; NC); NC with xylanase (NC + Xy); NC with probiotics (NC + Pro); NC with xylanase and probiotics mix (NC + XyPro); and NC with BMD (NC + BMD). Data were analyzed as one-way ANOVA. At 35 and 42 days, birds fed with NC + XyPro and NC + BMD were heavier (P < 0.05) than birds fed with NC. Improvement in feed conversion ratio (FCR) (P = 0.0001) was observed from 1 to 42 days by ~3 points in both NC + XyPro and NC + BMD compared to NC. The NC + XyPro reduced lesion scores by 66% compared to PC and NC. Litter C. perfringens cell count was reduced by ~16% with supplementation of XyPro or BMD. It can be concluded that a blend of xylanase (10 XU/g feed) and Bacillus spp. [1 × 10⁵ colony forming units (CFU)/g feed] can be used as an alternative to AGP in low-energy broiler diets.

Efficacy of probiotic Enterococcus faecium in combination with diclazuril against coccidiosis in experimentally infected broilers

AIMS

The study was conducted to investigate the combination of a probiotic strain of Enterococcus faecium and diclazuril to control coccidiosis in broilers.

METHODS AND RESULTS

A total of 240 one-day-old female broiler chicks were divided into eight groups (30 chicks per group): prophylactic groups (G1, G2 and G3) and therapeutic groups (G4, G5 and G6) and two control groups (untreated infected, G7 and untreated uninfected, G8 controls). In the prophylactic approach, diclazuril alone (G1), probiotic alone (G2) or a mixture of both probiotic and diclazuril (G3) was orally administered to the chicks via drinking water 10 days prior to the infection. However, in the therapeutic approach, G4, G5 and G6 birds were administered diclazuril alone, probiotic alone and diclazuril+probiotic mix, respectively, in drinking water for five consecutive days after the appearance of clinical signs of coccidiosis. Birds of both approaches and G7 were experimentally infected with 25 × 10³ Eimeria-sporulated oocysts. Chicks in G3 showed the highest weight gain, the lowest lesion score, a low oocyst count and mortality rate among the challenged groups. Moderate lesion scores and oocyst counts were observed in chickens administered probiotics prophylactically. In the therapeutic approach, broilers in G6 but not G5 displayed a decreased mortality rate and lesion score in comparison to those in G7 and G8. However, the result of the probiotic-treated group was not significantly different from that in the untreated infected control group.

CONCLUSION

The probiotic supplementation as a prophylactic approach can decrease the adverse effects of eimerian infection. In addition, the probiotic and diclazuril mix achieved a considerable improvement in the growth performance. Therefore, probiotic plus diclazuril combination achieved a synergistic effect.

SIGNIFICANCE AND IMPACT OF THE STUDY

Investigation into the synergism/antagonism between a probiotic and diclazuril as anticoccidial agent and the difference in the timing of administration.

Effects of three probiotic Bacillus on growth performance, digestive enzyme activities, antioxidative capacity, serum immunity, and biochemical parameters in broilers

This study was conducted to evaluate the effects of three Bacillus strains on growth performance, digestive enzyme activities, antioxidative capacity, serum immunity, and biochemical parameters in broilers. A total of 360 one-day-old Ross 308 chicks were randomly allocated into four groups with three replicates per group (n = 30). The control group was fed a basal diet, whereas the other groups fed basal diet supplemented with either Bacillus subtilis natto or Bacillus licheniformis or Bacillus cereus (10⁸  cfu/kg) for 42 days, respectively. The results revealed that the probiotic-treated groups markedly improved final body weight, daily weight gain, and the activities of trypsin, amylase, lipase and total protease (p < 0.05). Moreover, chicks fed probiotics had higher serum glutathione peroxidase activity and O₂ ^- level, as well as hepatic catalase and superoxide dismutase activities, whereas malondialdehyde levels in serum and liver were reduced (p < 0.05). The significant increased IgA (p < 0.05) was observed in the probiotics groups as compared to the control group. In addition, dietary administration of probiotic strain markedly reduced the levels of serum ammonia, uric acid, total cholesterol, and triglyceride. Taken together, these three probiotic Bacillus showed beneficial effects on chickens with minor strain specificity.

Effect of synbiotic supplementation on layer production and cecal Salmonella load during a Salmonella challenge

This study analyzed the inhibitory effects of a synbiotic product (PoultryStar® me) on production parameters, intestinal microflora profile, and immune parameters in laying hens with and without a Salmonella challenge. The synbiotic product contained 4 probiotic bacterial strains (Lactobacillus reuteri, Enterococcus faecium, Bifidobacterium animalis, and Pediococcus acidilactici) and a prebiotic fructooligosaccharide. Layers were supplemented with the synbiotic from d of hatch to 28 wk of age. At 16 wk of age, birds were either vaccinated with Salmonella enterica Enteritidis (SE) vaccine or left unvaccinated. At 24 wk of age, a portion of the birds was challenged with 1 × 109 CFU of SE or left unchallenged, resulting in a 3 (vaccinated, challenged, or both vaccinated and challenged) X 2 (control and synbiotics) factorial arrangement of treatments. At 18 and 20 wk of age, birds fed synbiotics in both vaccinated and unvaccinated groups had increased (P < 0.05) BW more than those in the un-supplemented groups. Birds fed synbiotics had 0.7, 17.8, 21.7, 3, and 4.2% higher (P < 0.05) hen d egg production (HDEP) at 19, 20, 21, 22, and 23 wk of age, compared to the birds without supplementation, respectively. After administering the SE challenge, supplemented birds had 3, 6.7, 4.3, 12.5, and 14.4% higher (P < 0.05) HDEP at 24, 25, 26, 27, and 28 wk of age, compared to the birds not supplemented, respectively. Irrespective of the vaccination status, birds fed synbiotics and challenged with SE had a lower (P < 0.05) SE cecal load compared to the un-supplemented groups. At 22 d post Salmonella challenge, birds supplemented, vaccinated, and challenged had the highest bile IgA content. It can be concluded that supplementation of the synbiotic product could be beneficial to layer diets as a growth promoter, performance enhancer, and for protection against SE infection.

A comparative analysis of microbial profile of Guinea fowl and chicken using metagenomic approach

Probiotics are live microbial feed supplements that promote growth and health to the host by minimizing non-essential and pathogenic microorganisms in the host’s gastrointestinal tract (GIT). The campaign to minimize excessive use of antibiotics in poultry production has necessitated development of probiotics with broad application in multiple poultry species. Design of such probiotics requires understanding of the diversity or similarity in microbial profiles among avian species of economic importance. Therefore, the objective of this research was to establish and compare the microbial profiles of the GIT of Guinea fowl and chicken and to establish the microbial diversity or similarity between the two avian species. A metagenomic approach consisting of the amplification and sequence analysis of the hypervariable regions V1-V9 of the 16S rRNA gene was used to identify the GIT microbes. Collectively, we detected more than 150 microbial families. The total number of microbial species detected in the chicken GIT was higher than that found in the Guinea Fowl GIT. Our studies also revealed phylogenetic diversity among the microbial species found in chicken and guinea fowl. The phylum Firmicutes was most abundant in both avian species whereas Phylum Actinobacteria was most abundant in chickens than Guinea fowls. The diversity of the microbial profiles found in broiler chickens and Guinea fowls suggest that the design of effective avian probiotics would require species specificity.

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 in vitro 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 in vivo 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 21 days. 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.

Influence of dietary inclusion of Bacillus licheniformis on laying performance, egg quality, antioxidant enzyme activities, and intestinal barrier function of laying hens

This experiment was conducted to evaluate the effects of dietary inclusion of Bacillus licheniformis on laying performance, egg quality, antioxidant enzyme activities, and intestinal barrier function of laying hens. Hy-Line Variety W-36 hens (n = 540; 28 wk of age) were randomized into 6 groups, each group with 6 replications (n = 15). The control group received the basal diet formulated with maize and soybean meal. The treatment groups received the same basal diets supplemented with 0.01, 0.02, 0.03, 0.06, and 0.09% Bacillus licheniformis powder (2 × 10(10) cfu/g) for an 8-wk trial. The results showed that dietary supplementation with 0.01 and 0.03% B. licheniformis significantly increased egg production and egg mass. However, no significant differences were observed in egg weight, feed consumption, and feed conversion efficiency among the 6 groups. Supplementation with different levels of B. licheniformis was found to be effective in improvement of egg quality by increasing egg shell thickness and strength. Compared with control, d-lactate content, diamine oxidase activity, and adrenocorticotropic hormone level in serum decreased significantly, and the level of estradiol and follicle-stimulating hormone increased significantly in plasma of all the experimental groups. Dietary supplementation with B. licheniformis increased the intestinal villus height and reduced the crypt depth. In conclusion, dietary inclusion of B. licheniformis could improve laying performance and egg quality significantly in a dose-dependent manner by decreasing the stress response, upregulating the growth hormone, and improving intestinal health.

A multi-microbe probiotic formulation processed at low and high drying temperatures: effects on growth performance, nutrient retention and caecal microbiology of broilers

1. Two experiments were conducted to evaluate a multi-microbe probiotic formulation processed at low (LT) or high (HT) drying temperature. 2. In both the experiments, 640 d-old Ross male chicks were randomly allotted to 4 treatments on the basis of initial BW for 35 d experiments. 3. In experiment one, dietary treatments were a negative control (NC; basal diet without any antimicrobial); positive control (PC; basal diet +10 mg/kg avilamycin); basal diet with 0·3% probiotic LT; and basal diet with 0·3% probiotic HT. 4. Improved overall weight gain, FCR and retention of CP were observed in birds fed the PC and probiotic diets when compared with birds fed the NC diet. At d 21, birds fed the probiotic and NC diets had more caecal Bifidobacterium and total anaerobes than birds fed the PC diet; while birds fed the PC and probiotic diets had fewer caecal Clostridium than birds fed the NC diet at d 35. 5. In experiment two, a 2 × 2 factorial arrangement of treatments was employed to evaluate the effects of two concentrations of probiotic HT (0·30 or 0·60%) and avilamycin (0 or 10 mg/kg). 6. Birds fed the 0·60% probiotic HT diet showed improved overall weight gain and CP retention, higher Lactobacillus and Bifidobacterium in the caecum, and reduced Clostridium and coliforms in the caecum. Inclusion of avilamycin improved the overall weight gain and feed intake, and reduced the caecal Clostridium and Bifidobacterium population. 7. In conclusion, high drying temperature had no effect on the efficacy of the multi-microbe probiotic formulation; while the probiotic HT formulation was more effective at the 0·60% level. Moreover, inclusion of avilamycin improved performance of birds but did not have any interaction with probiotics.

Growth Performance and Meat Quality of Broiler Chickens Supplemented with Bacillus licheniformis in Drinking Water

A feeding trial was conducted to investigate effects of Bacillus licheniformis on growth performance and meat quality of broilers. Nine hundred one-d-old broiler chicks were randomly assigned to 3 experimental groups with three replicate pens of 100 broiler chicks. Three treatments were i) control, ii) basal diets supplemented with 1 ml of B. licheniformis for each in feed water per day iii) basal diets supplemented with 2 ml of B. licheniformis per chick in feed water per day. The supplementation of B. licheniformis significantly increased body weight in grower chickens (p<0.05), and significantly improved the feed conversion in 3 to 6 and 0 to 6 wk feeding period compared with the control group (p<0.05). Additionally, the supplement also resulted in increased protein and free amino acid contents, and decreased fat content in chicken breast fillet (p<0.05). Furthermore, improvement in sensory attributes was observed in broilers fed with the probiotic. In conclusion, B. licheniformis treatments resulted in a significant increase (p<0.05) in broiler productivity based on an index taking into account daily weight gain and feed conversion rate. Meanwhile, the probiotic contributed towards an improvement of the chemical, nutritional and sensorial characteristics of breast fillet. Overall, the study indicates that B. licheniformis can be used as a growth promoter and meat quality enhancer in broiler poultry.

Assessing the effect of administering probiotics in water or as a feed supplement on broiler performance and immune response

1. Two routes of probiotic administration in broiler farms, in water and in feed, were compared using 360 one-day-old male broiler chickens. Controls received no probiotics or antimicrobials. The water group received a probiotic preparation at a rate of 0.5 g/l, and the feed group received it at an inclusion rate of 1 g/kg. 2. Performance of broilers in terms body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) improved when probiotic was provided via drinking water, compared to the control and feed groups. Probiotic administration reduced plasma cholesterol and triglyceride concentrations. 3. Spleen (28 and 42 d) and bursa (42 d) relative weights were influenced by method of probiotic administration, which also improved T-cell dependent skin thickness response to phytohaemagglutinin (PHA) injection. The effect of challenge by dinitrochlorobenzene (DNCB) depended on the method of probiotic administration. 4. The method of probiotic administration can influence the performance and immune competence of birds, and administration via drinking water appears to be superior to the more conventional in-feed supplementation method.

The role of probiotics in the poultry industry

The increase of productivity in the poultry industry has been accompanied by various impacts, including emergence of a large variety of pathogens and bacterial resistance. These impacts are in part due to the indiscriminate use of chemotherapeutic agents as a result of management practices in rearing cycles. This review provides a summary of the use of probiotics for prevention of bacterial diseases in poultry, as well as demonstrating the potential role of probiotics in the growth performance and immune response of poultry, safety and wholesomeness of dressed poultry meat evidencing consumer's protection, with a critical evaluation of results obtained to date.

Evaluation of the efficacy of a probiotic containing Lactobacillus, Bifidobacterium, Enterococcus, and Pediococcus strains in promoting broiler performance and modulating cecal microflora composition and metabolic activities

The aim of this work was to investigate the efficacy of a new multibacterial species probiotic in broiler nutrition. The probiotic contained 2 Lactobacillus strains, 1 Bifidobacterium strain, 1 Enterococcus strain, and 1 Pediococcus strain. Four hundred 1-d-old male Cobb broilers were allocated in 4 experimental treatments for 6 wk. The experimental treatments received a corn-soybean basal diet and were as follows: "control," with no other additions; "probiotic in feed and water," (PFW) with probiotic administered at 1 g/kg of feed for the whole period and in water on scheduled intervals during the first 4 wk; "probiotic in feed," (PF) with probiotic in feed as in PFW; and "antibiotic," (AB) with addition of avilamycin at 2.5 mg/kg of feed. Salinomycin Na was used as a coccidiostat. Each treatment had 5 replicates of 20 broilers. Treatment effects on parameters of broiler performance and cecal microbial ecology were determined. Broiler BW, feed intake, and feed conversion ratio were determined on a weekly and overall basis. Cecal microflora composition, concentration of volatile fatty acids, and activities of 5 bacterial glycolytic enzymes (alpha-galactosidase, beta-galactosidase, alpha-glucosidase, beta-glucosidase, and beta-glucuronidase) were determined at the end of the experiment. Overall, treatment PFW displayed a growth-promoting effect that did not differ from AB. Overall, feed conversion ratio in treatment AB was significantly better (P < or = 0.01) than the control treatment, whereas treatments PFW and PF were intermediate and not different from AB. Concentrations of bacteria belonging to Bifidobacterium spp., Lactobacillus spp., and gram-positive cocci were significantly (P < or = 0.05) higher in treatments PFW and PF compared with the control and AB treatments. Treatments PFW and PF had significantly higher specific activities of alpha-galactosidase and beta-galactosidase compared with the control and AB treatments. In conclusion, probiotic treatment PFW displayed a growth-promoting effect that was comparable to avilamycin treatment. In addition, treatments PFW and PF modulated the composition and, to an extent, the activities of the cecal microflora, resulting in a significant probiotic effect.

The effect of dietary probiotic supplementation on tibial bone characteristics and strength in broilers

A 6-wk study with 50 birds was conducted to investigate the effects of a dietary supplemental probiotic on morphometric parameters and yield stress of the tibia. Twenty-five 1-d-old broiler chicks were assigned to a control or an experimental diet containing Bacillus licheniformis and Bacillus subtilis (BioPlus 2B, CHR Hansen BioSystems, Denmark, Ugur Ecza Deposu, Turkiye Distributoru, Adapazari 41400, Turkey; each containing 2.3 x 10(8) cfu/g of spores) supplemented to the starter and finisher diets at 500 g/1000 kg of feed. Each diet was replicated 5 times with 5 birds in each replicate. Tibiotarsi weight, length, and weight/length index, robusticity index, diaphysis diameter, modulus of elasticity, yield stress parameters, and percentage Ca content were not affected by the dietary supplementation of probiotic, whereas thickness of the medial and lateral wall of the tibia, tibiotarsal index, percentage ash, and P content were significantly improved by the probiotic. Medullary canal diameter of the tibia of the birds fed the control diet was significantly greater than that of birds fed the probiotic diet. There was no treatment impact on live performance of the birds throughout the 6-wk feeding trial.

Investigating the Effects of Commercial Probiotics on Broiler Chick Quality and Production Efficiency

A study was undertaken to test the effect of 2 commercially available probiotics on the production efficiency of broiler chickens hatched from the same breeder flock at 3 different ages (28, 43, and 57 wk). At each of the 3 breeder flock ages, 1,600 broiler chickens were hatched and randomly allocated to 1 of 4 treatments: 1) no probiotics (control), 2) probiotic 1 administered in the drinking water, 3) probiotic 1 administered as a spray, and 4) probiotic 2 administered in the feed. A coccidiostat was included in the feed, but no other antimicrobial agents were given. Broilers were then reared on straw litter in identical floor pens for a period of 6 wk. There were no significant differences in broiler BW, feed conversion, or mortality between the probiotic treatments and the control group in any of the trials. The 43-wk-old breeder flock had the highest fertility and hatchability and the lowest percentage of chicks culled at hatching. Throughout the broiler production period, the broilers from the 43- and 57-wk-old breeder flocks had higher BW and weight gains than the broilers produced at 28 wk of breeder flock age. Broiler feed conversion over the 6-wk production period decreased as the breeder flock aged. Probiotics had no effect on chick quality or production efficiency in broilers produced by the breeder flock ages examined.

Beneficial lactobacilli in food and feed: long-term use, biodiversity and proposals for specific and realistic safety assessments

Lactobacilli have played a crucial role in the production of fermented products for millennia. Their probiotic effects have recently been studied and used in new products. Isolated cases of lactobacillemia have been reported in at-risk populations, but lactobacilli present an essentially negligible biological risk. We analyzed the current European guidelines for safety assessment in food/feed and conclude that they are not relevant for the Lactobacillus genus. We propose new specific guidelines, beginning by granting a 'long-standing presumption of safety' status to Lactobacillus genus based on its long history of safe use. Then, based on the available body of knowledge and intended use, only such tests as are useful will be necessary before attributing 'qualified presumption of safety' status.

Efeito da microbiota cecal e do Lactobacillus salivarius inoculados in ovo em aves desafiadas com Salmonella enterica sorovar Enteritidis

Ovos embrionados provenientes de matrizes pesadas foram inoculados na câmara de ar com microbiota cecal total, microbiota cecal diluída e cultura de Lactobacillus salivarius, no 18º dia de incubação. Dois dias após o nascimento, as aves foram desafiadas com Salmonella enterica sorovar Enteritidis (SE) e, cinco dias após o desafio, avaliou-se a presença da bactéria no fígado e ceco. O efeito de exclusão competitiva, após o desafio com SE, somente foi observado pela ausência da bactéria no fígado das aves tratadas in ovo com L. salivarius. A inoculação in ovo de microbiota cecal indefinida ou diluída não reduziu a colonização de SE no fígado e no ceco das aves, incluindo, neste último, também o tratamento com L. salivarius. Nenhum dos tratamentos in ovo determinou índice de eclodibilidade superior a 65%.

In vitro inhibition of Eimeria tenella invasion by indigenous chicken Lactobacillus species

The aim of this study was to determine the effects of indigenous chicken Lactobacillus species isolates from different parts of the gastrointestinal tract on Eimeria tenella invasion in vitro and to characterise the nature of inhibition, if any. The effects of competitive exclusion, steric interference and bacterial extracellular factors on E. tenella invasion were examined in an MDBK cell model. Several Lactobacillus species were initially isolated from chickens and identified by biochemical characteristics and 16S-rRNA. All Lactobacillus species isolates tested, significantly inhibited E. tenella invasion. Steric interference did not affect parasite invasion. Extracellular metabolic factors secreted by Lactobacillus species isolates into the surrounding media were shown to inhibit parasite invasion and these factors appeared to be heat stable. These results show that the natural microflora of poultry can provide a source of E. tenella-inhibiting Lactobacillus species in vitro, and thus may contribute to the control of Eimeria infection.

Effects of probiotics: alone and in a mixture of Biosacc plus Zinc Bacitracin on the caecal microflora of Japanese quail

The aim of this study was to investigate the effects of two commercially available probiotics, alone and in combination with an antibiotic, on the caecal flora of Japanese quail (Coturnix coturnix japonica) reared under unstressed conditions. Thirty-four 90-day-old Japanese quail were selected for this study. The birds were divided into four groups, two groups of nine birds and two groups of eight birds. The animals in these groups were given feed containing 0.5 kg per tonne of probiotics alone (Protexin or Biosacc), a mixture of probiotic plus antibiotic (Biosacc plus Zinc Bacitracin at 0.5 and 0.0525 ppm, respectively), and a group where no supplement was added to be used as controls. The total count of aerobic bacteria, lactobacilli, enterobacteriaceae, coliforms, enteroccoci, salmonellae, sulphite-reducing anaerobic bacteria (clostridia), and pH values in the caecal content of the birds were examined. No significant differences were detected among the four groups for pH values and bacterial number (p>0.05), except for sulphite-reducing anaerobic bacteria (p<0.001). These results suggest that the use of probiotics alone and/or a mixture of a probiotic plus antibiotic as a feed supplement does not have a major suppressing effect on the majority of bacterial groups in the caecal flora of mature, healthy Japanese quail reared in unstressed conditions.

Impact of two probiotic Lactobacillus strains feeding on fecal lactobacilli and weight gains in chicken

Two probiotic strains, Lactobacillus agilis JCM 1048 and L. salivarius subsp. salicinius JCM 1230 isolated from chicken intestine, exhibited probiotic characteristics that can be applied for chicken production. After 7 days of probiotic feeding (FD7), the count of intestinal lactobacilli in the probiotic group (group P, n=10) was significantly (p<0.05) higher than that in the control group (group C, n=9). After 40 days of probiotic feeding (FD40), the lactobacilli and enterococci counts were stable but the Enterobacteriaceae number was significantly reduced (p<0.05). A total of 163 isolated lactobacilli were identified as the L. acidophilus/gallinarum group (49.7%), L. agilis (30.7%), L. salivarius (9.2%), L. reuteri (9.2%), and Lactobacillus spp. (1.2%). The probiotic lactobacilli positively affected the Lactobacillus biota in chickens at FD7, with a significant increase in the number (p<0.05) of L. agilis and group P. The viable counts of each Lactobacillus species at FD40, however, showed no differences between two groups. An increasing incidence of L. agilis was also noted with probiotic feeding. The probiotic effect of two strains resulted in significantly increased weight gains (10.7%) of group P in comparison with group C at FD40 (p<0.01).

Characterization of lactobacilli towards their use as probiotic adjuncts in poultry

AIMS

A total of 112 strains of lactic acid bacteria of duck origin were studied for their use as a probiotic feed supplement.

METHODS AND RESULTS

In vitro studies included aggregation, co-aggregation, cell surface hydrophobicity and adhesion activities on poultry crop cells and human Hep2-cells. Additionally, growth with bile acids (chicken bile, ox gall and taurocholic acid) and tolerance to acidic pH were tested. Among all the isolates, two strains (Lactobacillus animalis TMW 1.972 and Lactobacillus salivarius TMW 1.992) were selected for a survival test in poultry. Monitoring and differentiation of these strains was achieved by selective detection as rifampicin and erythromycin double-resistant mutants. After a single feed administration, both micro-organisms were shown to persist in the crop and caecum of ducks for a period of 18 and 22 days, respectively. For identification of Lact. animalis and Lact. salivarius, two specific PCRs targeted against 16S rDNA were developed.

CONCLUSIONS

Within the autochtoneous microflora of ducks, two strains of lactobacilli exhibited strong potential as probiotic adjuncts. The results indicate that the natural gut microflora of poultry serves as an excellent source for optimal strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

A general strategy for the selection of probiotic strains is presented. The suggested sequence of tests allows identification of the most promising candidates within complex ecosystems or large strain collections with minimal expenditure.

Digestive and bacterial enzyme activities in broilers fed diets supplemented with Lactobacillus cultures

A study was carried out to investigate the effects of adherent Lactobacillus cultures on 1) amylolytic, lipolytic, and proteolytic enzyme activities in the contents of the small intestine (from the distal end of the duodenum to the ileocecal junction) and 2) bacterial beta-glucuronidase and beta-glucosidase activities in the intestinal contents and feces of broiler chickens. Three dietary treatments were randomly assigned to three groups of chicks, i.e., basal diet only (control group), basal diet + 0.1% dried culture of Lactobacillus acidophilus, and basal diet + 0.1% dried culture of a mixture of 12 Lactobacillus strains. The results showed that supplementation of the adherent Lactobacillus cultures to chickens, either as a single strain of L. acidophilus or as a mixture of 12 Lactobacillus strains, increased significantly (P < 0.05) the levels of amylase in the small intestine. However, the proteolytic and lipolytic activities in the small intestine were not affected by addition of either of the adherent Lactobacillus cultures. Addition of either L. acidophilus or a mixture of 12 Lactobacillus strains was also found to reduce significantly (P < 0.05) the intestinal and fecal beta-glucuronidase and fecal beta-glucosidase but not the intestinal beta-glucosidase at 40 d of feeding.

Growth performance, intestinal microbial populations, and serum cholesterol of broilers fed diets containing Lactobacillus cultures

A study was conducted to determine the effects of adherent Lactobacillus culture on growth performance, intestinal microbial population, and serum cholesterol level of broilers. Four dietary treatments, consisting of the basal diet (control), basal diet + 0.05, 0.10, or 0.15% Lactobacillus culture (LC), were fed to 2,000 Arbor Acres broiler chicks from 1 to 42 d of age (DOA). The chicks were randomly assigned to 40 cages (50 chicks per cage, 10 cages per diet). The experimental period was 42 d. Body weights and feed to gain ratio were measured at 21 and 42 DOA. The intestinal microbial populations and serum cholesterol levels were determined at 10, 20, 30, and 40 DOA. The results showed that body weights and feed to gain ratios were improved significantly (P < 0.05) when compared to control broilers for broilers fed diets containing 0.05 or 0.10% LC, but not 0.15% LC, at 21 and 42 DOA. Coliform counts in the cecum of birds receiving 0.05% LC at 10, 20, and 30 DOA, and 0.10% at 10 and 20 DOA were significantly lower (P < 0.05) than those of the control birds. The total aerobes, total anaerobes, lactobacilli, and streptococci in the small intestines and ceca of the control birds were not significantly different from those of the treated groups. Serum cholesterol levels were significantly lower (P < 0.05) in broilers fed the three diets containing LC at 30 DOA, and in the birds fed 0.05 or 0.10% LC at 20 DOA.

Effect of feeding diets containing an antibiotic, a probiotic, or yucca extract on growth and intestinal urease activity in broiler chicks

A 6-wk study was conducted to determine the effect of feeding diets containing an antibiotic, a probiotic, or yucca extract on daily gain, feed conversion ratio, and urease activity and ammonia production in intestinal contents of broiler chicks. Four replicates of 10 broiler chicks (average body weight, 48 g) each were assigned to a control or diets containing 0.1% chloroxytetracycline (antibiotic), 0.1% Lactobacillus casei (probiotic), or 0.2% yucca extract. Feeding a diet containing the probiotic significantly (P < 0.05) increased average daily gain during the first 3-wk period compared to the control (30.7 vs 28.7 g). This increase was partly accounted for by increased feed intake. During the first 3 wk, feeding the diet containing probiotic significantly (P < 0.05) decreased urease activity (per gram of collected contents) in small intestinal contents but not in large intestinal contents, compared with the control. Urease activity determined at 6 wk of age was not significantly affected by diet. Our studies indicate that dietary probiotic decreases urease activity in the small intestinal contents of young chicks and thus may be beneficial for improving animal health and growth, especially during early life.

Principles of ex ovo competitive exclusion and in ovo administration of Lactobacillus reuteri

The data that have been presented indicate that the in ovo use of competitive exclusion (CE) agents is feasible for both chickens and turkeys. However, there are many pitfalls that await the use of in ovo application of CE agents, including the use of nonspecies-specific intestinal microbes and the use of harmful proteolytic, gas-producing and toxin-producing intestinal microbes. Of the potential CE agents that have posthatch application, only Lactobacillus reuteri has been shown to be safe and effective in terms of not affecting hatchability and in having a prolonged effect in the hatched chick or poult. Lactobacillus reuteri administration in ovo increases its rate of intestinal colonization and decreases the colonization of Salmonella and Escherichia coli in both chicks and poults. Additionally, mortality due to in-hatcher exposure to E. coli or Salmonella is reduced with in ovo L. reuteri. Use of antibiotics in ovo may preclude the use of co-administered CE agents, but Gentamicin and L. reuteri are a compatible mixture when administered in ovo in separate compartments. Nevertheless, the intestinal morphology can be affected by both the CE agent and by antibiotics. Lactobacillus reuteri both in ovo and ex ovo will increase villus height and crypt depth, and Gentamicin in ovo causes a shortening and blunting of the villus. Both Gentamicin and L. reuteri in ovo suppress potentially pathogenic enteric microbes, but with diminished antibiotic effects shortening and blunting of the intestinal villi does not correct itself. Goblet cell numbers increase significantly on the ileum villus of chicks treated with Gentamicin in ovo, and this is presumably due to the increase in potentially pathogenic bacteria in the intestinal tract. Diminishing antibiotic effects posthatch would then negatively affect the absorption of nutrients and reduce growth at least in a transitory manner. Thus, L reuteri administration in ovo singly or in combination with Gentamicin followed by L reuteri via drinking water or feed appears to have potential to control many enteric pathogens in poultry. Additional work in the use of in ovo CE cultures is mandated because there is a world-wide movement to reduce antibiotic use in poultry due to increased microbial resistance to antibiotics. Use of naturally occurring intestinal bacterial cultures, either in mixed culture or as single well-defined cultures, has potential for immediate use in the poultry industry.

Effect of maduramicin and monensin on survival of Lactobacillus salivarius 51R administered in the crop and caeca of young chickens

A rifampicin-resistant Lactobacillus salivarius 51R was administered orally to newly hatched broiler chickens. The resistance to rifampicin enabled us to differentiate the organism administered from indigenous strains. One day after inoculation, Lactobacillus salivarius 51R dominated among lactobacilli in the crop and caeca of all inoculated chickens, even in those ones receiving maduramicin and monensin at 5 and 100 mg per kg of feed mixture, respectively. Coliform counts in both crop and caeca of inoculated chickens were significantly lowered on the first day after treatment. Also, counts of the crop enterococci were decreased in inoculated chickens. Rifampicin-resistant lactobacilli were still present in high numbers in the crop and caecal contents of inoculated chickens sampled 5 days after inoculation. Differences in counts of total lactobacilli, coliform bacteria, and enterococci were mostly nonsignificant in these samples. Our results demonstrate that (i) bacterial counts in the chicken gut were influenced by probiotic Lactobacillus administration, and (ii) chicken lactobacilli are resistant to ionophore coccidiostats under in vivo conditions.