Gut microorganisms play an important role in the digestion of their host animals. The purpose of this research was to isolate and assess the enzyme-producing microbes from the Apostichopusjaponicus gut. Thirty-nine st...Gut microorganisms play an important role in the digestion of their host animals. The purpose of this research was to isolate and assess the enzyme-producing microbes from the Apostichopusjaponicus gut. Thirty-nine strains that can produce at least one of the three digestive enzymes （protease, amylase, and cellulase） were qualitatively screened based on their extracellular enzyme-producing abilities. The enzyme-producing strains clustered into eight groups at the genetic similarity level of 100% by analyzing the restriction patterns of 16S rDNA amplified with Mbo L Phylogenetic analysis revealed that 37 strains belonged to the genus Bacillus and two were members of the genus Virgibacillus. Enzyme-producing capability results indicate that the main enzyme-producing microflora in the A.japonicus gut was Bacillus, which can produce protease, amylase, and cellulase. Virgibacillus, however, can only produce protease. The high enzyme-producing capability of the isolates suggests that the gut microbiota play an important role in the sea cucumber digestive process.展开更多
A feeding experiment was conducted to investigate the effect of Bacillus subtilis bacterium and its suitable level on survival and growth rate of juvenile Macrobrachium rosenbergii （de Man） during March 28 to May 28...A feeding experiment was conducted to investigate the effect of Bacillus subtilis bacterium and its suitable level on survival and growth rate of juvenile Macrobrachium rosenbergii （de Man） during March 28 to May 28, 2010. A B. subtilis bacterium isolated from chicken intestine was added to commercial prawn feed as a probiotic. Six diets were prepared by soaking prawn feed into the B. subtilis to achieve 10^10, 10^9, 10^8, 10^7 and 106 levels with a non-treated control. After 60 days, the prawns fed diet at level 10^8 showed a higher mean weight gain （593.45 g） or 170.29% increase in growth over control. The mean weight gain showed a decreasing trend as the B. subtilis level decreased from 10^8 to 10^6 and the B. subtilis level increased from 10^8 to 10^10 in the diets. There were significant differences （P 〈 0.05） in weight gain, feed intake, daily growth and feed conversion ratio （FCR） among treated and controlled groups. There were significant differences （P 〈 0.05） among treatments and control in survival rate but no significant differences （P 〉 0.05） in water quality and biochemical composition among treated and controlled groups. Clearly, treated with B. subtilis appeared to enhance growth and survival of M. rosenbergii. It was concluded that the tested strain may be a promising probiotics for M. rosenbergii at a level of 10^8 B. subtilis into the prawn feed.展开更多
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A412)the National Natural Science Foundation of China(No.41106145)+2 种基金the National Key Technology R&D Program of China(No.2011BAD13B02)the Science and Technology Development Planning Project of Shandong Province(No.2012GGA06021)the Key Laboratory of Mariculture&Stock Enhancement in North China’s Sea,Ministry of Agriculture,China(No.2014-MSENC-KF-03)
文摘Gut microorganisms play an important role in the digestion of their host animals. The purpose of this research was to isolate and assess the enzyme-producing microbes from the Apostichopusjaponicus gut. Thirty-nine strains that can produce at least one of the three digestive enzymes （protease, amylase, and cellulase） were qualitatively screened based on their extracellular enzyme-producing abilities. The enzyme-producing strains clustered into eight groups at the genetic similarity level of 100% by analyzing the restriction patterns of 16S rDNA amplified with Mbo L Phylogenetic analysis revealed that 37 strains belonged to the genus Bacillus and two were members of the genus Virgibacillus. Enzyme-producing capability results indicate that the main enzyme-producing microflora in the A.japonicus gut was Bacillus, which can produce protease, amylase, and cellulase. Virgibacillus, however, can only produce protease. The high enzyme-producing capability of the isolates suggests that the gut microbiota play an important role in the sea cucumber digestive process.
文摘A feeding experiment was conducted to investigate the effect of Bacillus subtilis bacterium and its suitable level on survival and growth rate of juvenile Macrobrachium rosenbergii （de Man） during March 28 to May 28, 2010. A B. subtilis bacterium isolated from chicken intestine was added to commercial prawn feed as a probiotic. Six diets were prepared by soaking prawn feed into the B. subtilis to achieve 10^10, 10^9, 10^8, 10^7 and 106 levels with a non-treated control. After 60 days, the prawns fed diet at level 10^8 showed a higher mean weight gain （593.45 g） or 170.29% increase in growth over control. The mean weight gain showed a decreasing trend as the B. subtilis level decreased from 10^8 to 10^6 and the B. subtilis level increased from 10^8 to 10^10 in the diets. There were significant differences （P 〈 0.05） in weight gain, feed intake, daily growth and feed conversion ratio （FCR） among treated and controlled groups. There were significant differences （P 〈 0.05） among treatments and control in survival rate but no significant differences （P 〉 0.05） in water quality and biochemical composition among treated and controlled groups. Clearly, treated with B. subtilis appeared to enhance growth and survival of M. rosenbergii. It was concluded that the tested strain may be a promising probiotics for M. rosenbergii at a level of 10^8 B. subtilis into the prawn feed.
