| The experiment was conducted to investigate the effect of Bacillus cereus and Alpinia densibracteata on mouse growth following indexes of digestive tube weight, jejunal morphology, caecal microbial population, intestinal mucosal immune function and jejunal digestive enzyme activity and so on, supplemented with basal diets. 150 (15±2g weight and healthy) male KUN MING mouse were randomly assigned to 5 groups with 3 repetitions. Five different diets were supplemented during experiment. The 5 groups were group A-the control group (basal diet), group B-the antibiotic group(100mg/kg OTC), group C-Alpinia densibracteata group(2% powdered stem tuber of Alpinia densibracteata),group D-Bacillus cereus group (1‰additive of Bacillus cereus), group E-the combination of Bacillus cereus and Alpinia densibracteata group (1‰additive of Bacillus cereus and 2% powdered stem tuber of Alpinia densibracteata). The experimental stage was 28 days.The experimental results showed that:1. After the whole experiment, Bacillus cereus and Alpinia densibracteata additives could improve average weekly weight gain significantly in comparison with the control (P＜0.05), which improved by 11.72%, 5.81%.They decreased feed-weight ratio moreover. Bacillus cereus addition could decrease by 15.84%, whose effect was surpassed to the common antibiotic-OTC.2. Bacillus cereus, Alpinia densibracteata and OTC additives could increase the villus height in jejunum significantly (P＜0.05) after 14,28 days.On the 28th day,OTC addition increased crypt depth in jejunum in comparison with the blank control.Compared to five groups on Villus height:Crypt depth ratio in jejunum,the combination group＞Bacillus cereus group＞Alpinia densibracteata group＞OTC group＞the blank control group.There were no significant deviations on myenteron thickness in jejunum among all the groups (P＞0.05).On the 28th day, there were no significant deviations on index of digestive tube weight (P＞0.05).3. Bacillus cereus addition significantly decreased count of aerobic bacterium such as E coli, Enterococci, Staphylococci and elevated count of beneficial anaerobic bacterium such as Bifidobacterium, Lactobacillus in caecal contents of mouse(P＜0.05).OTC restrained growth of aerobic bacterium such as E coli, Enterococci, Staphylococci, but restrained growth of beneficial anaerobic bacterium such as Bifidobacterium, Lactobacillus at the same time. Alpinia densibracteata had no significant growth promotion to Bacillus cereus and Escherichia coli in vitro.It had some effects of regulation on caecal microbial population, but not significant(P＞0.05).4. Bacillus cereus, Alpinia densibracteata additives improved digestive enzyme acti-vities such as protease, amylase in jejunal contents of mouse(P＜0.05).After the whole experiment -28 days,Bacillus cereus, Alpinia densibracteata elevated protease activity by 33.07%, 16.66% and elevated amylase activity by 47.35%, 11.84% in comparison with the control.OTC could elevated protease activity significantly during the prior weeks, but there was no significant change on amylase activity during the whole experiment.5. Bacillus cereus addition significantly improved sIgA concentration in mouse jejunal juice,I.e it enhanced intestinal mucosal immune function. However,OTC restrained intestinal mucosal immune function of mouse to some extent. Alpinia densibracteata had no significant effect on intestinal mucosal immune function(P＞0.05).6. Combination application of Bacillus cereus and Alpinia densibracteata was surpass-ed to addition alone,I.e there was some synergistic action between them,but there was no significant difference in comparison with Bacillus cereus used alone(P＞0.05).
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