Interaction effect of photoperiod and light intensity on the growth performance, immune and survival of Great sturgeon, Huso huso reared in the larval stage (endo genus)

The aim of this study was to increase the production efficiency of reared Great sturgeon (Huso huso) in the larval stage (after hatching until absorption of the yolk sac) under the corresponding influence of photoperiod and light intensity. In this study, the larvae from the after hatching to the complete absorption of the yolk sac were exposed to four light intensities (0-10; 70-100; 200-170 and 350-330lux) and five photoperiods (24L:00D; 16L:08D; 12L:12D; 08L: 16D and 00L: 24D) treatments and the control group. Each treatment and control group had three replications (70 g of larvae). At the end of the experiment, after sampling and biometry of the samples, growth factors including weight and final length, weight gain (WG), specific growth rate (SGR), condition factor (CF), body weight increase (BWI), daily growth (ADG) and survival rate (SR) were done using special mathematical formula. Also, some enzymatic, immune and biochemical factors of body plasma were measured and analyzed statistically. The results showed that although all growth indices (WG, SGR, CF, BWI and ADG) in the treatment of photoperiod of 24L:00D and light intensity of 100lux were in the maximum growth (p<0.05), but the maximum survival percentage of larvae (65.32%) compared to other treatments, especially the maximum growth treatment (7.41%), was observed in the photoperiod of 08L:16D and light intensity of 100lux treatment (p<0.05). Also, enzymatic, biochemical and immune indices were desirable conditions in the larvae of optimal growth treatment (treatment 11) compared to many other treatments (p<0.05). In total, the most suitable photoperiod and light intensity to increase the production efficiency of larvae with a yolk sac of reared great sturgeon, was the treatment of 08L:16D and 100lux.