The comparative efficiency of different probiotics in diets for broilers
The application of in-feed antibiotics in commercial poultry production results in the resistance to these drugs in the strains pathogenic for poultry and human; this problem has given rise to the intense worldwide search for the alternative growth stimulators including probiotics. In a trial in commercial conditions of Timashevskaya poultry farm (Samara Province) on 4 treatments of Cobb-500 broilers (500 birds per treatment, 1-38 days of age) the effects of three different dietary probiotics on the productive performance and biochemical blood parameters were comparatively studied. It was found that all three probiotics beneficially affected productive performance: live bodyweight at 38 days of age in the treatments fed probiotics was higher in compare to control by 3.80-16.03%, average daily weight gains higher by 3.87-16.34%, mortality level lower by 1-4%, feed conversion ratio lower by 2.03-13.71%, European production efficiency factor (EPEF) higher by 16-92 points. The most effective from the productivity standpoint was Probiotic No 2 fed at the dose 3,000 ppm recommended by its producer. Concentrations of total protein, total albumins, glucose, and total cholesterol in blood serum in all treatments fed probiotics were higher in compare to control evidencing the intensification of protein, carbohydrate, and lipid metabolism by all studied probiotics.