The combined effects of feeding time and dietary lipid levels on growth performance in juvenile beluga sturgeon Huso huso

Juvenile beluga sturgeon, Huso huso (initial weight 50 ± 0.2 g), were fed with two lipid levels (120 g kg−1 lipid as low-energy diet, LE; 240 g kg−1 lipid as high-energy diet, HE) at different feeding times for 8 weeks, and the effects on growth, hematology, muscle composition, and apparent digestibility coefficients of dry matter, lipid, and protein were examined. Feeding times were as follows: (1) at 09:00 and 16:00 (under light regime), (2) at 21:00 and 04:00 (under dark regime), and (3) at 13:00 and 20:00 (under light–dark regime). Dietary lipid levels did not affect the hematological indices or apparent digestibility coefficients of dietary nutrients (P > 0.05); however, they affected the growth and muscle composition (P < 0.05). The fish fed with HE diet had the highest final weight (174.2 – 175.9 g), specific growth rate (2.44 – 2.47 % day−1), weight gain (246.5 – 252.6 %), and the lowest feed conversion ratio (1.10 – 1.12). The fish fed with HE diet had the highest muscle lipid content (26.6 – 35.2 g kg−1). Unlike the lipid levels, feeding times did not significantly affect growth, hematological parameters, nutrient digestibility, and muscle composition (P > 0.05). Accordingly, juvenile beluga sturgeon can be fed at different times of the day without suffering growth loss, because probably, they have a low dependency on vision to detect food.