Increasing counts of intestinal lactic acid producing bacteria is considered beneficial to gut health and performance of commercial broiler chickens. Fresh fecal microbial assays from a broiler pen trial were used to calculate correlations between Lactobacilli (LAC) counts and live performance. A total of 1,240 Cobb 500 male chicks were randomly assigned to 6 dietary treatments with 10 replicate pens of 19 chicks each. Diets included negative control basals (starter, grower, and finisher) and basals plus antibiotic and/or bacillus spores from 0-42 d. All diets were steam pelleted (crumbles/pellets). Bacteria enumerated in fresh fecal samples (log10 cfu/g sample) from most but not all pens included Enterobacteriaceae (ENT), Lactobacilli, and total anerobes (TAN). The BW, feed conversion ratio (FCR), and mortality % (MORT) were measured at 14, 21, 35, and 42 d. Pearson correlations (Statistix 8) were calculated between LAC or LAC/TAN % and BW, FCR, or MORT. Using treatment means, significant (P≤0.10) correlations (r) were found between: 21-d BW and 15-d LAC, 0.765; 0-14 d FCR and 15-d LAC, -0.807; and 0-35 d MORT and 29-d ENT, 0.742. Using pen means, correlations were: 14-d FCR and 15-d LAC, -0.389; 21-d FCR and 15-d LAC, -0.276; 35-d MORT and 29-d LAC, -0.211; 42-d BW and 42-d LAC, 0.221; 42-d FCR and 42-d LAC/TAN %, 0.246; and 42-d MORT and 42-d LAC/TAN %, 0.221. Using pen means, a correlation was found between 15-d LAC/TAN % and 15-d ENT, -0.290. In conclusion, evidence was presented that fresh fecal counts, indicative of intestinal microflora populations, for LAC or LAC/TAN % had a positive correlation with BW and negative correlations with FCR or MORT, and LAC/TAN % had a negative correlation with ENT, which were all beneficial effects. Therefore, efforts to increase fecal (intestinal) LAC and LAC/TAN % counts should improve broiler chicken live performance.
Key Words:antibiotic, broiler, bacillus, correlation, lactobacilli
Abstract for International Poultry Scientific Forum, Atlanta, GA, January 25-26, 2010