Manipulation of photoperiod in growth factors of beluga sturgeon Huso huso

Abstract

The beluga sturgeon is considered as the most important species for caviar production. This study aimed to evaluate effects of photoperiod manipulation on growth factors of beluga sturgeon. The six photoperiod regimes (light: dark cycle) including natural photoperiod (control), 24L: 0D, 16L: 8D, 12L: 12D, 8L: 16D and 0L: 24D with the three replicates. The treatment 5 (8L: 16D) gained the greatest final weight (2194.4 g) after 73 rearing days and besides, the treatments 4, 3 and 1 (12L: 12D, 16L: 8D, and Control) can be considered as the good photoperiod regimes for beluga sturgeon. The continuous light (24L: 0D) and continuous dark (0L: 24D) significantly (P < 0.05) reduced the final weight of fish to 1804.2 g and 1976.1 g, respectively. Regulated photoperiod significantly improve growth rate and food conversion ratio of beluga sturgeon.    Key words: Beluga sturgeon, Huso huso, growth factors, photoperiod.