Application of flow cytometric cell cycle analysis to the assessment of condition and growth in larvae of a freshwater teleost Galaxias olidus

Through its ability to measure cell DNA content, flow cytometric analysis ( FCA) is a technique capable of accurately assessing the position of cells i n the cell cycle. Using FCA to measure the proportion of dividing and nondi viding cells, an index was created that allows the amount of cell division within larval fish tissues to be quantified. To assess the suitability of t he cell division index (CDI) as an indicator of growth and condition in fis h larvae, analyses were divided into four parts. These examined the effects of temperature, nutrition, time of day, and geographic location on the CDI of brain tissue from Galaxias olidus larvae. The index was sensitive to, f irstly, differences in the brain CDI of larvae reared at 12 and 20 degrees C and, secondly, to significant fluctuations in mean brain CDI from larvae sampled over 24 h. FCA also revealed significant differences in the CDI of starving and fed larvae. Overall, this study indicates that FCA may be suit able as an indicator of growth and condition in both laboratory-reared and wild fish larvae.