Effects Of Dietary Supplementation Of Bacillus On Performance And Immune Function In Broilers

The present experiments were conducted to study utilizing characteristics of Bacillus additives, which have a wide range of biological activity such as asepsis and innocuity, promoting growth, regulating immune function, strengthening the power of resistance of the body, raising digestibility of nutrients and so on, in order to search for the succedaneum of antibiotics, develop the green feed additive, product safety production of livestock and poultry, and study the influence of different type of Bacillus in diets on broiler growth performance, metabolism of energy and protein, slaughter performance and meat quality, and immune function by the growth and metabolic trials.In the growth trial, single-factor test design was adopted, and a total of 600 1-day-old, healthy Arbor Acre male broilers with near body weight were selected and randomly allotted into five treatments, each treatment consisted of five replicates with 30 broilers in each replicate. The control broilers were fed the basal diet. The broilers of the other four treatments were fed basal diet added respectively with 2×10~6 CFU/g Bacillus subtilis, 2×10~6 CFU/g Bacillus lichenlformis, 2×10~6 CFU/g Bacillus lentus, and 1×10~6 CFU/g Bacillus subtilis plus 1×10~6 CFU/g Bacillus lichenlformis. The growth trial lasted 42 days, and experimental diets and water were available ad libitum during the entire experimental period. Then the metabolic trial was conducted at the age of 49 days. The experimental results were showed as follows:(1) All the three types of Bacillus improved growth performance of broilers, and the combination of Bacillus subtilis and Bacillus lichenlformis with a ratio of 1:1 had a better effect. In addition, Bacillus lentus improved ADG and feed conversion efficiency of broilers during the first three weeks.(2) Bacillus supplemented in diets tended to enhance the metabolic rate of energy and protein.(3) Bacillus supplemented in diets improved significantly slaughter performance and meat quality in broilers.(4) All kinds of Bacillus enhanced immune organ index and phagocytic function of mononuclear macrophage in broilers, and Bacillus subtilis had the best effect.