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Babaei S.S.,Tarbiat Modares University | Abedian Kenari A.,Tarbiat Modares University | Nazari R.,Shahid Rajaee Sturgeon Hatchery Center

The development of digestive enzymes from the stomach (pepsin), pancreas (trypsin, chymotrypsin, α-amylase and lipase) and intestine (alkaline phosphatase) was studied in Persian sturgeon (Acipenser persicus) from hatching to the juvenile stage at 40. days post hatching (dph). Larvae were obtained from artificial propagation of one male and one female and transferred to larval culture tanks where, after yolk sac absorption (9. dph at 17-18 °C), they were fed with Artemia urmiana and Daphnia sp. The assessment of the activity of digestive enzymes showed that at the onset of exogenous feeding, gastric glands were already functional as indicated by the increase in pepsin specific activity. In contrast, alkaline proteases like trypsin and chymotrypsin decreased their specific activity after the onset of exogenous feeding, indicating the importance of these types of enzymes in the cleavage of yolk proteins during the endogenous feeding phase and the replacement of the larval alkaline-type digestion by a juvenile-type acid digestion. After the first feeding, amylase and lipase specific activities increased. Such increments in the activity of amylase might be genetically programmed to better digest carbohydrates in diets with the goal of sparing proteins during the larval stage, whereas the increase in lipase was related to changes in the lipid content of live prey and the progressive maturation of the pancreatic function during larval development. Changes in enzyme activities from the stomach and pancreas were coupled with that in the intestine (brush border membrane), where the specific activity of alkaline phosphatase progressively increased until 19-24. dph and remained constant thereafter, indicated the maturation of the intestine and the achievement of a juvenile-like mode of digestion. Considering these data on the digestive enzymes from the pancreas, stomach and intestine, Persian sturgeon larvae might be weaned around 19-24. dph, as larvae have achieved the complete maturation of their digestive functions by this date. This developmental process, and particularly for the digestive functions, can be considered as a reference to evaluate the effect of a formulated micro diets feeding on larvae. © 2011 Elsevier B.V. Source

Ovissipour M.,Tarbiat Modares University | Abedian Kenari A.,Tarbiat Modares University | Motamedzadegan A.,Sari University of Agricultural Sciences and Natural Resources | Nazari R.M.,Shahid Rajaee Sturgeon Hatchery Center
Food and Bioprocess Technology

Fish protein hydrolysate was produced from the viscera of yellowfin tuna (Thunnus albacares). Hydrolysis conditions (enzyme activity, temperature, and time) were optimized using response surface methodology. A factorial design was applied to minimize enzyme utilization and modeling of degree of hydrolysis (r 2 = 0.94). Lack-of-fit test revealed a non-significant value for the model, indicating that the regression equation was adequate for predicting the degree of hydrolysis under any combination of the variables (P < 0.05). The optimum conditions to reach the highest degree of hydrolysis were: 60.4 °C, 90.25 min, and a protease (Alcalase 2.4 L) activity of 70.22 AU/kg protein. The spray-dried tuna visceral protein hydrolysates had relatively high protein (72.34%) and low lipid (1.43%) content. The chemical score of the hydrolysate indicated that it fulfils adult human nutritional requirements except for methionine. Lysine and methionine were the first and the second limiting amino acids in that order. Phenylalanine was the predominant amino acid in the hydrolysates with respect to common carp requirement. In addition, the protein efficiency ratio of tuna visceral hydrolysate was 2. 85-5. 35. © 2010 Springer Science + Business Media, LLC. Source

Molla A.E.,Shahid Rajaee Sturgeon Hatchery Center | Amirkolaie A.K.,Sari University of Agricultural Sciences and Natural Resources
Journal of Applied Ichthyology

The main goal of the study was to evaluate the effects of different protein and energy levels on growth performance of Asipenser persicus fry. The fish were fed nine experimental diets containing three protein levels (35, 40, and 45%) and three energy levels (16.3, 18.2, and 19.4kJg-1 dry matter) according to a 2×2 factorial design. The diets were assigned to 27 thanks with 50 fish in each, with three replicates for each treatment. Growth-related parameters were improved with increase of dietary protein (P<0.01). However a change in energy contents of the diets did not have any impact on growth performance. The interaction between protein and energy showed that effect of protein on growth parameters depends on energy levels of the diet. Protein efficiency ratio improved with an increase in protein content of the diet (P<0.01). Persian sturgeon fry showed a lower individual variation in final weight by feeding on high-protein content diets. In conclusion, A. persicus fry needs a diet containing 45% protein to attain maximum growth. Protein content of diet can induce individual variation in growth of Persian sturgeon fry. © 2011 Blackwell Verlag, Berlin. Source

Ovissipour M.,Washington State University | Abedian Kenari A.,Tarbiat Modares University | Nazari R.,Shahid Rajaee Sturgeon Hatchery Center | Motamedzadegan A.,Sari University of Agricultural Sciences and Natural Resources | Rasco B.,Washington State University
Aquaculture Research

The effect of fish protein hydrolysate (FPH) on the growth, feed utilization, digestive enzymes, gut microflora and resistance to bacterial challenge in Persian sturgeon (Acipenser persicus) larvae during a 45-day feeding trial has been investigated. Artificial diets containing different levels of tuna visceral protein hydrolysate (PH0, PH10, PH25 and PH50) and live foods (Artemia: 5 days, Daphnia: 40 days) were fed to Persian sturgeon larvae. Larvae fed on the PH10 and PH25 had growth, feed utilization, protein content and trypsin activity significantly better than PH0 and PH50 groups (P < 0.05). Condition factors, survival rate and pepsin activity were not significantly different (P > 0.05). Brush border membrane enzymes to cytosolic enzyme ratio revealed that maturation had been occurred in 41 days post hatch (dph) at moderate FPH levels. In 54 dph larvae, this ratio was not affected by the level of FPH in the diet. No significant differences were observed in the total number of gut microflora or in the resistance to Aeromonas hydrophila (P > 0.05), whereas lactic acid bacteria was significantly higher in PH50 (P < 0.05). The results of this study show that application of moderate levels of FPH in Persian sturgeon diets could enhance larvae performance due to the early maturation in intestinal. © 2012 John Wiley & Sons Ltd. Source

Zahedi S.,Hormozgan University | Mirvaghefi A.,University of Tehran | Rafati M.,Islamc Azad University | Rafiee G.,University of Tehran | And 4 more authors.
Marine and Freshwater Behaviour and Physiology

This study reports the 96-h LC50 value and tissue copper (Cu) levels and biochemical changes in juvenile fish (Acipenser persicus) exposed to 0.026 mg/l ambient Cu for 1, 7 and 14 days. It then examined the recovery of the same parameters after placing the juvenile fish in clean water for a further period of 28 days. The intestine, kidney and gill Cu levels, plasma glucose, total protein, triglyceride, cortisol, triiodothyronine and thyroxine concentrations, liver protein contents, liver catalase, superoxide dismutase (SOD) and glutathione S-transferase activities were studied. The 96-h LC50 value of Cu was 0.502 mg/l for juvenile A. persicus. The results indicate that Cu exposure produced significant accumulations of Cu in gills and kidney over the treatment time. Sublethal dose of Cu resulted in a short-term increase in plasma glucose, total protein and cortisol levels that decreased with time. After the 28-day recovery phase, there were significant differences in kidney Cu levels and triglyceride concentrations as well as SOD activities between recovery fish treatments and their control groups on day 42. The 28-day recovery phase caused significant decreases in total protein levels and SOD activities of Cu-exposed fish on day 42 compared to day 14. The results suggest that 28 days are insufficient for complete recovery to Cu exposure by juveniles and a longer period would be required for full recovery. Moreover, the study showed that the recovery phase following Cu exposure could change biochemical parameters to levels that are not close to those seen during exposure or control levels. © 2014 Taylor & Francis. Source

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