title: A robust flow-cytometric protocol for assessing growth rate of hatchery-reared barramundi Lates calcarifer larvae.
abstract: In this study, a flow-cytometric cell cycle analysis method to assess instantaneous growth rate of whole larvae of the Australian barramundi Lates calcarifer was developed and validated. High-resolution DNA measurements of either fresh, frozen or RNAlater-preserved larvae (gap0-gap1, G(0) -G(1), coefficient of variation (c.v.) < 3, 4 and 5%, respectively) enabled the deconvolution of the DNA histogram and assignment of the proportion of nuclei into cell cycle compartments G(0) -G(1), S (DNA synthesis) and G(2) -M (Gap2-Mitosis). This technique can be also used for individual fish tissues such as brain, liver, fin and muscle. For the first time, the combined proportion of replicating nuclei (into S and G(2) -M phases) of whole fish larvae and absolute growth rate in length (mm day(-1)) has been correlated in commercial aquaculture conditions. Fast growing L. calcarifer larvae had an overall hyperplasia advantage as indicated by a greater proportion of cells in the S+G(2) -M phase compared with slow growing larvae, which might explain the increasing differences in size during culture. In a fasting trial, larvae ceased growth while maintaining the constant initial rates of cell division throughout a 6 day period. For a highly fed fast growing control group, cell division rates significantly increased after day 4. Flow-cytometric cell cycle analysis of whole fish larvae may provide fish biologists and aquaculturists with a better understanding of how cell division rates influence early growth in natural and artificial environments.
authors.affiliation: Centre for Sustainable Tropical Fisheries and Aquaculture, School of Marine and Tropical Biology, James Cook University, Townsville, Qld 4811, Australia. jose.domingos@my.jcu.edu.au
authors.forename: J A
authors.initials: JA
authors.lastname: Domingos
authors.forename: P
authors.initials: P
authors.lastname: Fromm
authors.forename: C
authors.initials: C
authors.lastname: Smith-Keune
authors.forename: D R
authors.initials: DR
authors.lastname: Jerry
mesh_terms: D000818:Animals; D001315:Australia; D002455:Cell Division / Q000502:physiology; D005398:Fisheries / Q000379:methods*; D005434:Flow Cytometry; D010473:Perciformes / Q000254:growth & development*; D015203:Reproducibility of Results; D013312:Stress, Physiological / Q000502:physiology