Effect of diet composition on growth performance, hepatic metabolism and antioxidant activities in Siberian sturgeon (Acipenser baerii, Brandt, 1869) submitted to starvation and refeeding

Many fish species undergo natural starvation periods. Adaptation to starvation is possible through the activation of behavioral, biochemical and physiological mechanisms. Knowledge of the effect of dietary nutrients on the intermediary metabolism during starvation and refeeding can be useful to improve fish health and optimize aquaculture production. To analyze the effect of dietary nutrients on liver metabolism of Siberian sturgeon (Acipenser baerii) submitted to starvation and refeeding, four isoenergetic diets differing in nutrient composition were designed: LP-St (38 % protein, 12 % lipid, 36 % carbohydrate), HP-St (44 % protein, 10 % lipid, 30 % carbohydrate), LP-L (38 % protein, 18 % lipid, 25 % carbohydrate) and HP-L (44 % protein, 16 % lipid, 22 % carbohydrate). Four groups of fish were fed 3 weeks to satiety with the corresponding diet, starved for 2 weeks and then refed 5 weeks to satiety on the same diet. Starvation mobilized the hepatic lipid store to a greater extent than glycogen. Starvation increased superoxide dismutase activity irrespective of the diet, while low protein diets (LP-St and LP-L) increased catalase activity. The oxidative damage decreased after 5 weeks of refeeding. Refeeding the starved fish on the HP-St diet promoted the greatest growth performance. In addition to report for the first time the effect of diet composition on growth, liver composition and antioxidant activities in Siberian sturgeon submitted to starvation and refeeding, our findings suggest that refeeding on HP-St diet stimulated the use of dietary carbohydrates and allowed a protein sparing effect in Siberian sturgeon

Physicochemical and Biochemical Properties of Trypsin-like Enzyme from Two Sturgeon Species

This work aimed to determine the physicochemical and biochemical properties of trypsin from beluga Huso huso and sevruga Acipenser stellatus, two highly valuable sturgeon species. According to the results obtained from the methods of casein-zymogram and inhibitory activity staining, the molecular weight of trypsin for sevruga and beluga was 27.5 and 29.5 kDa, respectively. Optimum pH and temperature values for both trypsins were recorded at 8.5 and 55 °C by BAPNA (a specific substrate), respectively. The stability of both trypsins was well-preserved at pH values from 6.0 to 11.0 and temperatures up to 50 °C. TLCK and SBTI, two specific trypsin inhibitors, showed a significant inhibitory effect on the enzymatic activity of both trypsins (p 0.05). The results of our study show that the properties of trypsin from beluga and sevruga are in agreement with data reported in bony fish and can contribute to the clear understanding of trypsin activity in these primitive species.info:eu-repo/semantics/publishedVersio

Histology of intestine and fatty acid profile of Pacific white shrimp (Litopenaeus vannamei) effected by dietary inulin

The effects of inulin were studied on the growth indices, intestinal morphology as well as fatty acid profile of the Pacific white shrimp, Litopenaeus vannamei with average weight 3.21±0.03 g for 5 weeks. The experiment was carried in triplicate, was conducted in circular PVC tanks of 300 L capacity with 25 shrimp per tank at the Aquaculture Center (Delvar, Bushehr province). Inulin was added to the diets at a 2 levels (0 and 2 percent). The shrimp were fed the experimental diets to visual satiety five times a day at 08:00, 12:00, 16:00, 20:00 and 24:00 h. No significant differences in growth performances (such as survival, feed conversion ratio (FCR), specific growth rate (SGR), Protein efficiency ratio (PER)) was observed, however, Dietary inulin brought about significantly improved 20:3n3 fatty acid content between the two treatments (P>0.05). Intestine epithelium cells height in the abdominal sections significantly (P< 0.05) were higher in shrimp fed by dietary inulin. The results of this study showed that supplement of 2% of inulin has positive effects on fatty acid profile and intestinal morphology in Litopenaeus vannamei.Publishe