Preparation of fermented the stems and leave of Scutellaria baicalensis with chicken-derived β-glucosidase-producing mixed bacteria and their effects on the digestion and immune function of broilers

In order to improve the utilization of stem and leaves of Scutellaria baicalensis and clarify its promoting effect on digestion and immune function of broilers, in this study, the bran pressure method combined with gastrointestinal simulation in vitro was used to screen mixed bacteria with high-yield β-glucosidase from chicken. The optimal fermentation conditions of stem and leaves of Scutellaria baicalensis were determined by cellulose degradation rate. Ninety 14-day-old yellow feathered broilers with similar body weight were randomly divided into three groups, which were the blank control group, unfermented feed additive group and fermented feel additive group, respectively, with 3 replicates in each group, with 10 chicken in each replicate. The pre-test period was 1 week, and the normal test period was 6 weeks. The blank control group was fed the basic diet. Unfermented feed additive group was fed the basic diet with 8% unfermented Scutellaria baicalensis stem and leaf feed additive. Fermented feed additive group was fed the basic diet with 8% fermented Scutellaria baicalensis stem and leaf feed additive. The average daily gain, average daily feed intake and feed to weight ratio of experimental broilers were calculated. The apparent digestibility of dry matter, crude protein, crude fat and crude ash in broilers at 42-64 days, 62-64 days of age were measured and calculated by endogenous indicator method. At 64 days of age, spleen, thymus and bursa of Fabricius indices were calculated and the concentrations of IgM, IgG and IgA in serum were detected. The results showed that the optimal screening condition of β-glucosidase-producing mixed bacteria was 4% bran content, culture for 48 h. The optimum fermentation conditions of Scutellaria baicalensis stems and leaves were 25% inoculation amount of mixed bacteria, 30 ℃ for 15 days, and the mass fraction of its wild baicalin was 0.56%. Compared with blank control group, the apparent digestibility of crude protein and crude ash(62-64 days of age) was significantly increased(P<0.05), and the content of IgG in serum was significantly increased(P<0.05) in unfermented Scutellaria baicalensis stem and leaf feed additive group. Compared with the blank control group, the average daily gain, apparent digestibility of dry matter, crude protein, crude fat and crude ash were significantly increased(P<0.05), and feed to weight ratio was significantly reduced(P<0.05). The indexes of spleen, thymus and bursa of Fabricius and the contents of IgG, IgA and IgM in serum were significantly increased(P<0.05) in fermented feed additive group. Compared with the unfermented feed additive group, the feed to weight ratio of broilers at 21-42 days of age in fermented feed additive group was significantly decreased by 2.77%(P<0.05), the average daily gain of broilers at 43-64 days of age was significantly increased by 11.20%(P<0.05), and the feed to weight ratio was significantly decreased by 10.06%(P<0.05), the apparent digestibility of dry matter, crude protein, crude fat and crude ash, the indexes of spleen, thymus and bursa of Fabricius and the contents of IgG, IgA and IgM in serum were significantly increased(P<0.05). The results indicated that the fermentation of Scutellaria baicalensis could enhance the apparent digestibility and immune level of yellow-feathered broilers.