Study on the function of micro-organisms coexisting in the mass culture of the rotifer Brachionus plicatilis

This is the fundamental study for making clear the function of micro organisms which are co-existingin the culture of the rotifer Brachionus plicatilis,as a part of researches for dissolving themassmortality of long-term retardation of growth which still occur in mass culture of the animal.Results obtained are shown under.1. As a result of evaluating the changes of size frequencydistribution of suspending solids in the rotifr mass culture the animal did not start to ingestbacterial flocks till swept clear Nannochloropsis，the食物manually provided. After then,theclearance rate for bacterial flocks was near twice as much as for Nannochloropsis.2. Vitamin B 12这之前已经提供给了rotifer growth of the rotifer，这是一个小的容器Nannochloropsis or baker's yeast which are commonly used as food for rotifer culture. The mainsource of B 12 in mass culture was thought to be a metabolite of bacteria from the following20 % of bacterial strain isolated form rotifer mass culture had - B12产品，andproduced 1-5 ng/ml day of B12 in log phase of their growth stages,which is fairly high compared byB12 demand of the rotifer,and showed remarkable growth promotion in the axenic culture of the animalwhen put in as 10^7 - 10^<10> CFU/ml.3. The nutritive lucking of baker's yeast was thought toextend over a wide range from the results that the growth promotion of bacteria was与Nannochloropsis than in that with baker's yeast的rotifer culture provided相比as a basic food source

This is the fundamental study for making clear the function of micro organisms which are co-existing in the culture of the rotifer Brachionus plicatilis,as a part of researches for dissolving the massmortality of long-term retardation of growth which still occur in mass culture of the animal. Results obtained are shown under.1. As a result of evaluating the changes of size frequency distribution of suspending solids in the rotifr mass culture,the animal did not start to ingest bacterial flocks till swept clear Nannochloropsis,the food manually provided. After then,the clearance rate for bacterial flocks was near twice as much as for Nannochloropsis.2. Vitamin B 12 ,which had been proved to be essential for the growth of the rotifer,is contained little either in Nannochloropsis or baker's yeast which are commonly used as food for rotifer culture. The main source of B 12 in mass culture was thought to be a metabolite of bacteria from the following results. 20 % of bacterial strain isolated form rotifer mass culture had B12 productivity,and produced 1-5 ng/ml・day of B12 in log phase of their growth stages,which is fairly high compared by B12 demand of the rotifer,and showed remarkable growth promotion in the axenic culture of the animal when put in as 10^7 - 10^<10> CFU/ml.3. The nutritive lucking of baker's yeast was thought to extend over a wide range from the results that the growth promotion of B12-producing bacteria was more remarkable in the rotifer culture provided with Nannochloropsis than in that with baker's yeast as a basic food source.