Journal of Aquatic Ecology

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In the present study, the process of the skull development and calcification in Persian sturgeon (Acipenser persicus) was studied. Development of cartilage started after hatching around the head and notochord (10.6 mm, total length, TL) and the first calcification process occurred in dermopalatine and dentary bone jaw coincident with mixing feeding. The appearance of dermal skeletal on the body divided into three stages: (a) the yolk-sac (comprised of hatching to the late larval stage (12 DPH, 16 mm TL) in which no calcified structures became visible and the cartilaginous elements of skull with feeding and breathing roles have appeared. (b) the larval stage (between 16 and 20.25 mm, 23 DPH) in which, the first calcification process related to feeding and breathing occurred and weak mineralized dermal bones such as subopercle and supracleithrum developed; and (c) the metamorphosis stage between 27.25 and 83.3 mm TL) during which the formation of mineralized dermal bones occurred between 32 and 50 days post-hatching, and teeth were disappeared on dentary and dermopalatine bones. The results of this study could be useful for decreasing the larval mortality and improving the stock conservation programme of Persian sturgeon.
 

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The aim of this study was to determine the effects of replacement of fish meal by different levels of poultry by-product meal on growth performance and body composition in juvenile Siberian sturgeon (Acipenser baerii). One hundred thirty-five Siberian juvenile (initial body weight of 169.4 ± 2.39 g were randomly distributed in five treatments and three replicates. The experimental diets including different levels of poultry by-product meal (0, 20, 40, 60 and 80 percent) replaced for fish meal. The diet protein and fat contents were 41.22 and 15.06 percent and 19 MJ energy. During the 9-week feeding period, the fish were fed the experimental diets to apparent satiation three times daily (8:00, 14:00 and 18:00 clocks). At the end of rearing period, growth performance parameters and fish body composition were analyzed. The results showed no significant differences in growth performance among different treatments (P>0.05). Moreover, there were no significant differences in crude protein, crude fat, moisture and ash contents of the whole body among different treatments (P>0.05). The results of this study indicate that poultry by-product meal could be included up to 80 percent with no adverse effect on growth performance and body composition in juvenile Siberian sturgeon.