Effects of incubation and larval rearing temperature on histological changes of muscles in Caspian trout (Salmo trutta caspius Kessler, 1877) larvae

Abstract

Out of considerable environmental factors, temperature and its possible effects on life stages of Caspian trout investigated by natural incubation (8 ͦC) condition simulation comparing with cold (4 ͦC) and warm (12 ͦC) constant incubation temperatures in 3 well equipped incubators by water recycling systems. Green eggs triple treatments of wild and F1 cultured brooders were incubated. Incubation implemented in dark by using REDD water and DO–pH – temperature digital monitoring ended to yolk sac absorption and entering larval stage. Numbers and diameters of white fiber muscles measured and significant differences considered between three thermal treatments (P<0.05) in both wild and cultured stocks. The numbers of white fiber muscles in warm treatment by highest means (72.54) and lowest diameter (8.46 micrometer) compared with Cold treatment white fiber muscles diameter (20.59 micrometer) and numbers (50.72) which were the highest diameter and lowest numbers means between treatments. Hatching success stated considerable mortality for cold treatments and 8°C incubator improved the best temperature in wild treatment. Incubation temperature induced significant effect on white fiber muscles stated considerable index for flesh precursor muscles condition which is subject of natural stocks rehabilitation and domestication projects considerations.