1 Body size variation among strains of the Rotifer Brachionus plicatilis The United states – israel Binational Agriculture Reseach and Development Fund (BARD) 2 I. INTRODUCTION  Rotifer usefulness in aquaculture  Problem cosidered: size This subject: Body size variation among strains of the Rotifer Brachionus plicatilis  The object of this work: 3 3 II. Methods and materials  The 13 strains of Rotifer aren’t genetic non-relationship.  Laboratary conditions  Time: 1 year 4 5 1. Standard pre-experimetnal procedure  After 3 days of exponential growth, 200 females were removed to repeat the procedure  After another 3 days of exponential growth, preserved for measuring or initiate other experiment 200 females 200 ml of IOM + SF S E 6 2. Determinate body size Measuring body size on 50 adult females Body size: lorica length and width Tool: an ocular micrometer an ocular micrometer 7 3. Comparation of reproductive rates among strains  Consist 3 steps:  Pre- experemental conditions  Isolated singly  Count and calculate • Population growth rate (r): t NoNt r lnln − = 8 4. Size of a female over her lifespan (McK8_3 days) Collecting neonates Cultivation neonates Samples preservation procedure Measuring lorica size 9 5. The dietary effects on lorica size Other 6 diets were used Special culture conditions Transfer to new culture condition Samples were culture in SE Preserve 10 6. The effects of temperature, salinity and rotifer strain A factorial experemental design was used Transfer to standard pre-experemental conditions (after 7 days) After 6 days of growth, preserve and measure [...]... temperature for all strains 14 15 5 Main effects and interactions of salinity, temperature and rotifer strain on lorica length Lorica size is a characteristic that is largely genetically determined 16 III DISCUSSION 1 Range of lorica size  The other examinations suggest that the lorica size is a wide range:  Samples collected from serveral different locations by Ahlstrom  The range for laboratory-cultivated... on adult female body size (Fukusho & Iwamoto and Yufera) 18 3 The effects of temperature The effects of temperature on the body size are entirely dependent on strain type: The respones of all strains for temperature change 19 The role of temperature in cyclomorphosis was initiated by Fukusho and Iwamoto 20 Rotifer body size is primarily geneticaliy determined, not great influenced by enviromental . were removed to repeat the procedure  After another 3 days of exponential growth, preserved for measuring or initiate other experiment 200 females 200 ml of IOM + SF S E 6 2 effects on other rotifer strains Rotifers tended to be smaller at higher salinities and temperature for all strains 15 16 5. Main effects and interactions of salinity, temperature and rotifer strain. a wide range:  Samples collected from serveral different locations by Ahlstrom  The range for laboratory-cultivated is smaller than samples collected from nature 18 2. Dietary effects Type