Effects of feed acidifiers on growth performance, caecum microflora and nutrient and energy utilisation in broilers

Two experiments were conducted to assess the effects of dietary supplementation of acidifier on growth performance, caecum microflora and nutrient and energy digestibility of broilers. In Experiment 1, 840 1-d-old male Arbor Acres broilers were randomly distributed into 7 dietary treatments with 12 replicates: 1) T1, Negative, control diet without acidifier or antibiotics; 2) T2, Positive, Negative + antibiotics; 3) T3, Positive + 1 kg/tons acidifier; 4) T4, Positive + 2 kg/tons acidifier; 5) T5, Negative + 1 kg/tons acidifier; 6) T6, Negative + 2 kg/tons acidifier; 7) T7, Negative + 3 kg/tons acidifier. Addition of acidifier linearly increased (P=0.030) ADG and decreased (P=0.015) FCR in diets without antibiotics in the starter phase and linearly reduced (P=0.041) FCR in the grower phase. Supplementation of acidifier decreased (P=0.014) the number of Clostridium perfringens and increased (P=0.007) the number of Lactobacillus in the caecum. The number of Lactobacillus was linearly (P < 0.001) and quadratically (P < 0.001) increased as the concentration of acidifier increased. In Experiment 2, 216 21-d-old male Arbor Acres broilers were randomly distributed into 7 dietary treatments with 9 replicates. Endogenous losses were obtained from another 27 broilers. Supplementation of acidifier Pro GIT SF3 increased (P < 0.05) apparent digestibility of OM and CP. It also linearly increased (P < 0.05) apparent and total digestibility of dry matter, organic matter, crude protein and gross energy and increased (P < 0.05) the apparent and true metabolisable energy of the diet in the non-antibiotic diets. In conclusion, acidifier was effective in improving performance of broilers especially in diets without feed antibiotics. Acidifier also had beneficial effects on the composition of the microflora in the caecum and was as effective as antibiotics in improving nutrient digestibility and energy value in broilers. The most effective choice is to supply 3 kg/tons of diet acidifier without antibiotics.