Effects of Lactobacillus cultures on growth performance, abdominal fat deposition, serum lipids and weight of organs of broiler chickens

Estimation of 16S rRNA gene copy number in several probiotic Lactobacillus strains isolated from the gastrointestinal tract of chicken

The copy numbers of 16S rRNA genes in 12 probiotic Lactobacillus strains of poultry origin were analyzed. Genomic DNA of the strains was digested with restriction endonucleases that do not cut within the 16S rRNA gene of the strains. This was followed by Southern hybridization with a biotinylated probe complementary to the 16S rRNA gene. The copy number of the 16S rRNA gene within a Lactobacillus species was found to be conserved. From the hybridization results, Lactobacillus salivarius I 24 was estimated to have seven copies of the 16S rRNA gene, Lactobacillus panis C 17 to have five copies and Lactobacillus gallinarum strains I 16 and I 26 four copies. The 16S rRNA gene copy numbers of L. gallinarum and L. panis reported in the present study are the first record. Lactobacillus brevis strains I 12, I 23, I 25, I 211, I 218 and Lactobacillus reuteri strains C 1, C 10, C 16 were estimated to have at least four copies of the 16S rRNA gene. In addition, distinct rRNA restriction patterns which could discriminate the strains of L. reuteri and L. gallinarum were also detected. Information on 16S rRNA gene copy number is important for physiological, evolutionary and population studies of the bacteria.

Growth-promoting effects of single-dose intragastrically administered probiotics in chickens

1. Live body weight gain (WG) and food conversion efficiency (FCE) were measured over a 4-week period in chicks (female, Kabir strain), inoculated intragastrically at one week of age with either a single dose (1 ml) of 10(7) live bacterial cells of Lactobacillus fermentum (LBF) or a strain of Lactobacillus spp. (LB), named Autruche 4 (A4), suspended in 1 ml of phosphate-buffered saline (PBS, pH 7.0); controls (n = 10) were inoculated only with PBS. The same commercial chicken feed was used throughout the 4-week experiment. 2. Compared with the control group, WG to 8 and 21 d, and also liver weight, were significantly greater in LBF and A4 treatments and FCE improved in both of the experimental groups. Compared with the A4 treatment group, WG was significantly higher and FCE improved in the LBF-treated group. The effects of A4 treatment on chicks were similar to those in an earlier pilot experiment using the same methodology but with 1-week-old female chicks (Kabir) inoculated with either the A4 strain or strain of LB named Autruche 5. 3. It is concluded that a single dose of Lactobacillus fermentum or Lactobacillus spp. (Autruche 4) administered intragastrically improves WG and FCE of broiler chicks.

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.

Mortality and growth performance of broilers given drinking water supplemented with chicken-specific probiotics

For application in broiler production, we developed a multispecies (MSPB) and a chicken-specific (CSPB) probiotic preparation in fluid form. The MSPB contained different probiotic species of human origin, whereas the CSPB consisted of 7 Lactobacillus species isolated from the digestive tract of chickens. In a field trial with broilers, MSPB treatment resulted in a slight increase (by 1.84%) in broiler productivity based on an index taking into account daily weight gain, feed efficiency, and mortality. The CSPB treatment reduced mortality in 2 subsequent field trials and raised productivity by 2.94 and 8.70%. In a controlled trial with broilers showing a high index of productivity, probiotic treatment further raised productivity by 3.72%. Based on the present 4 studies in combination with 9 studies published earlier, it is suggested that with higher productivity rates of the broilers the effect of probiotics becomes smaller.

Effects of a dried Bacillus subtilis culture on egg quality

The effects of a dried Bacillus subtilis culture on the egg qualities of layers were studied. Nine hundred and sixty 25-wk-old Lohmann Brown layers were randomly divided into 5 groups with 192 layers in each group. Layers in group 1 were fed a control diet. The remaining groups received the control diet that contained either 20 mg of zinc bacitracin/kg and 4 mg of colistin sulfate/kg or 500, 1,000, or 1,500 mg of B. subtilis culture/ kg, respectively. The results showed improvements in egg production, feed consumption, and feed conversion (P < 0.05) of layers when 500 mg of B. subtilis culture/kg was added to the diets. The results also showed some special improvements in this group, including increases in eggshell thickness, yolk color, and Haugh unit, and decreases in yolk cholesterol concentration (P < 0.05). However, excessive doses of B. subtilis culture did not improve the performance of layers.

Genetic transformation of novel isolates of chicken Lactobacillus bearing probiotic features for expression of heterologous proteins: a tool to develop live oral vaccines

BACKGROUND

The use of lactic acid bacteria as vehicles to delivery antigens to immunize animals is a promising issue. When genetically modified, these bacteria can induce a specific local and systemic immune response against selected pathogens. Gastric acid and bile salts tolerance, production of antagonistic substances against pathogenic microorganisms, and adhesive ability to gut epithelium are other important characteristics that make these bacteria useful for oral immunization.

RESULTS

Bacteria isolated on de Man, Rogosa and Sharpe medium (MRS) from different gastrointestinal portions of broiler chicks were evaluated for their resistance to artificial gastric acid and bile salts, production of hydrogen peroxide, and cell surface hydrophobicity. Thirty-eight isolates were first typed at species level by PCR amplification of 16S-23S rRNA intergenic spacers using universal primers that anneal within 16S and 23S genes, followed by restriction digestion analyses of PCR amplicons (PCR-ARDRA). An expression cassette was assembled onto the pCR2.1-Topo vector by cloning the promoter, leader peptide, cell wall anchor and terminator sequences derived from the laminin binding S-layer protein gene of L. crispatus strain F5.7 (lbs gene). A sequence encoding the green fluorescent protein (GFP) was inserted as reporter gene, and an erythromycin resistance gene was added as selective marker. All constructs were able to express GFP in the cloning host E. coli XL1-Blue and different Lactobacillus strains as verified by FACS and laser scanning confocal microscopy.

CONCLUSION

Lactobacillus isolated from gastrointestinal tract of broiler chickens and selected for probiotic characteristics can be genetically modified by introducing an expression cassette into the lbs locus. The transformed bacteria expressed on its cell wall surface different fluorescent proteins used as reporters of promoter function. It is possible then that similar bacterial model expressing pathogen antigens can be used as live oral vaccines to immunize broilers against infectious diseases.

Broiler performance and intestinal alterations when fed drug-free diets

A study was carried out to investigate the effects of a drug-free feeding program on broiler performance and intestinal morphology. Chicks vaccinated against coccidia were randomly assigned to 4 dietary treatments: 1) negative control (NC), basal diet; 2) positive control (PC), diet 1 + Lincomycin; 3) program 1 (PG1); diet 1 + Bio-Mos, Vegpro, MTB-100, Acid Pak 4-Way, and All-Lac XCL; 4) and program 2 (PG2), diet 1 + Bio-Mos and All-Lac XCL, each of which were assigned to 13 pens (48 birds in each of 52 pens). Growth traits (BW, feed intake, yield, mortality, BW gain, and feed conversion rate) were obtained through 49 d. At d 14, 3 chicks per pen were challenged with coccidia. Segments of duodenum, ileum, and ceca were removed to measure intestinal morphology at d 14, 28, 35, and 49. Final BW gain of broilers on PC (2.736 kg) was numerically higher than those for NC (2.650 kg). Cumulative feed conversion rate at d 49 was improved (P < 0.05) in birds consuming PC and PG2 compared with NC. Overall, mortality was higher for birds consuming the NC (P < 0.05) than the PC, PG1, and PG2 diets. Interaction of dietary treatments with age and age alone were evident (P < 0.0001) for morphology of duodenum, ileum, and ceca. Lamina propria in ceca was thicker (P < 0.008) in broilers consuming the NC than PG1 and PG2 diets. The results of this study indicated that feeding birds without growth promoters resulted in higher mortality and decreased growth performance than did feeding a diet with an antibiotic, and the combination of Bio-Mos and All-Lac XCL helped to reduce negative effects.