ALBERT

Description: In this study, Daphnia longispina were fed with two freshwater green algae species, Chlorella vulgaris and Scenedesmus dimorphus, enriched with Docosahexaenoic acid (DHA). Chlorella vulgaris and Scenedesmus dimorphus were isolated and cultured for mass production. Three treatments with three replicates and a control group were considered to conduct this study. In order to investigate feeding, a total of 30 Acipenser persicus larvae with the initial mean weight of 68±3.6 mg were distributed into 12 plastic tanks of 60 L. Experimental fish larvae were fed daphnia collected from earthen ponds (as control group), daphnia enriched with Scenedesmus dimorphus (treatment 1), daphnia enriched with Chlorella vulgaris (treatment 2) and daphnia enriched with Chlorella vulgaris and Scenedesmus dimorphus (at the rates of 50%) (treatment 3). The microalgae density to enrich daphnia is estimated at 5×107 cells mL-1 . Fish larvae were fed at an amount of 30% body weight per day for four times. During the experimental period, water temperature, dissolved oxygen concentration and pH ranged between 18-24°C, 5.8-7.2 mg l-1 and 5.6-8.2, respectively. Monounsaturated fatty acids (MUFA) were the highest (32.3 %) in D. longispina enriched with Chlorella vulgaris and the highest concentration of polyunsaturated fatty acids (PUFA) (19.8%) was observed in D. longispina enriched with Scenedesmus dimorphus. The highest (21.6%) and lowest (13.2%) concentrations of PUFA in fish larvae were recorded in treatment 3 and the control group, respectively. The results obtained from the body weight increase (BWI %) revealed that there were significant differences (P≤0.05) between treatment 3 (daphnia enriched with chlorella and scenedesmus) and other treatments. The highest (5.5 ± 1.24 % day-1) and the lowest (4.6± 1.13% day-1) mean specific growth rates (SGR) were recorded in fish fed treatment 3 and the control group, respectively. The lowest (68%) and the highest (85%) survival rates were obtained in the control group and treatment 3, respectively.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: Effects of stocking density on growth, food conversion ratio, specific growth rate, percentage of body weight increase in Huso huso were studied in two phases. Juveniles below one year old with an average weight of 92.09±1.72 grams and stocking densities of 1.6, 2.8 and 4 kg/m2 in 3 replicates for 100 days were reared as the phase one group. One year old Huso huso with an average weight of 918.13±21.87 grams and stocking densities of 1.5, 2.5, 3.5 and 4.5 kg/m2 reared for 120 days in 2000 liter fiberglass tanks were the second phase. Results revealed negative impact of density on growth, percentage of body weight, and specific growth rate and food conversion ratio in both phases. In the first phase, lower stocking density (1.6 kg/m2) showed significant increase in growth rate (P〈0.05) as compared to 2.8 and 4 kg/m2 stocking densities resulting in 42.3% and 61 % growth rate respectively. Fish kept at 4 kg/m2 density showed malformed caudal fins and injured body due to higher tensions and contacts. In the second phase, the growth rate of fish decreased with increase in stocking density where fish with lower density (1.5 kg/m2) showed 7.2%, 15.6%, and 19.8% higher weight gain as compared to fish reared at 2.5, 3.5 and 4 kg/m2 stocking density. Analyses showed that with increase in stocking density, feeding area per fish decreases and tension between fish increases that leads to lower feeding efficiency. Based on the results, the recommended optimum stocking density for Huso huso individuals up to 90 grams is 1.5-2 kg/m2 and for fish individuals over 900 grams each the density should be kept at 2.5-3 kg/m2.

Description: Published

Description: Growth experiments were conducted in a random statistical design to determine the dietary requirements of Persian sturgeon, Acipenser persicus. In this study the effects of various dietary protein and energy and their optimum P/E proportion in diets was estimated on growth and carcass composition in A. persicus in the fingerling and grow out stage in three different phases. In the first phase, 16 semi pure diets with 4 protein levels (35, 40, 45 and 50%), each with four energy levels (18.5, 19.8, 21.1 and 22.4 megjoules/kg diet) and P/E proportion of 15.63 to 26.4 mg protein KJ-1 were formulated and fed to 960 A. persicus fingerlings, with a mean weight of 10.26±0.11 for 112 days. Three replicates were used for each experiment group. In the second phase, 432 A. persicus juveniles with a mean weight of 112.25±1.187 g were fed 12 semi purified diets with 3 protein levels (40, 45 and 50%) each with 4 energy levels (18.5, 19.8, 21.1 and 22.4 megjoules/kg diet) and P/E proportion of 18.9 to 26.4 mg protein KJ-1 for a period of 101 days using three replicates for each treatment. In the third phase, 384 juvenile A. persicus with a mean weight of 803.26±3.5 g were fed 16 diets for a period of 140 days. Two replicates were used for each treatment group. At the end of the experiment 30% of the fish population was randomly selected for carcass analysis to determine protein, lipid, moisture and ash content. Hepatosomatic index of the fish specimens was also determined. In the fingerling stage the fish fed 45 and 50% protein with 22.4 megjoules/kg diet energy exhibited the best growth indices [final body weight, percentage body weight increase (BWI%) and specific growth rate (SGR)] (P〈0.05). A diet containing 40% protein and 22.4 megjoules/kg diet energy with P/E ratio of 17.86 mg protein KJ-1 is the recommended diet for A. persicus in this stage. In the first phase higher growth rates were observed in fish fed diets containing 40% protein as compared to those fed diets containing 45 and 50% protein. Increasing energy levels to 21.1 and 22.4 megjoules/kg diet significantly increased (P〈0.05) growth indices. Highest values for growth indices belonged to fish fed diets containing 40% protein, 22.4 megjoules/kg diet energy and P/E ratios of 17.86 mg protein KJ-1. Final weight, BWI% and SGR in fish fed diets containing 40% protein were higher as compared to fish fed diets containing 35, 45 and 50% protein. Increasing energy levels to 22.4 megjoules/kg diet resulted in significant increase in growth indices as well as P/E ratios. Highest growth indices were recorded with diets containing 40% protein, 22.4 megjoules/kg diet energy and a P/E ratio of 17.86 mg protein KJ-1. Results obtained indicate that A. persicus showed better growth rates after acclimation to formulated diets, and therefore can be considered a suitable species for culture in captivity. On the basis of growth rate and carcass composition diet containing 40% protein, 20.1 to 25.9% lipid with a P/E ratio of 17.86 mg protein KJ-1 prepared from good quality fishmeal, fish oil and vegetable oil (sunflower or soybean oil) is recommended for feeding A. persicus in the fingerling and grow out stages.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: The present study that was conducted in collaboration with the departments of fish breeding and rearing, pathology and stock assessment of the International Sturgeon Research Institute at the Shahid Beheshti hatchery commenced on 26 February 2002 and ended on 7 June 2002 simultaneously with the breeding of beluga breeders. About 230 sturgeon specimens were studied of which 176 belonged to A. persicus spawners (103 females used for artificial breeding, 16 females not used for artificial breeding and 57 males), 46 A. stellatus spawners (13 females used for artificial breeding, 20 females not used for artificial breeding and 13 males), 3 A. nudiventris spawners and five H. huso female spawners. The total length of A. persicus spawners used for artificial breeding ranged from 131.5 to 211 cm with an average length of 172.5 cm and their weight ranged from 14 to 49 Kg. The minimum and maximum weight of eggs was 9 and 1.5 Kg, respectively and the minimum and maximum number of eggs per gram was 46 and 67 eggs, respectively. The maximum condition factor for spawners was 0.94 and the minimum condition factor was 0.49 (average 0.74). The age of spawners ranged from 12 to 20 years and the minimum and maximum time taken by spawners to respond to breeding was 293.8 and 486 t?. The GV1 in these breeders ranged from 6.2 to 17.5 and GV2 ranged from 5.3 to 9.3. The maximum fertilization rate was 100 %. The total length of A. persicus breeders that were not used in artificial breeding ranged from 152 to 203 cm and their weight ranged from 14 to 46 Kg. The minimum and maximum weight of eggs was 3.2 and 8.5 Kg, respectively and the minimum and maximum number of eggs per gram was 46 and 64 eggs, respectively. The maximum condition factor for spawners was 0.81 and the minimum condition factor was 0.39 (average 0.69). The age of spawners ranged from 16 to 19 years. The GV1 in these breeders ranged from 7.8 to 16.3 and GV2 ranged from 6.5 to 8.2. Total length of male A. persicus breeders ranged from 129 to 178 cm and their weight ranged from 7 to 25.5 Kg. The maximum age of these breeders was 17 years and their minimum age was 11 years. The condition factor in these breeders ranged from 0.33 to 0.84. In A. stellatus breeders total length ranged from 128.5 to 163 cm and weight ranged from 7 to 14.5 Kg. The minimum and maximum weight of eggs was 1 and 2.7 Kg, respectively and the minimum and maximum number of eggs per gram was 67 and 129 eggs, respectively. The maximum condition factor for spawners was 0.58 and the minimum condition factor was 0.37 (average 0.48). The age of spawners ranged from 10 to 16 years and the minimum and maximum time taken by spawners to respond to breeding was 276.8 and 737.3 t?. The GV1 in these breeders ranged from 9.1 to16.2 and GV2 ranged from 3.64 to11. The maximum fertilization rate was 90 %. The total length of A. stellatus breeders that were not used in artificial breeding ranged from 129.5 to 165.5 cm and their weight ranged from 7.3 to 17 Kg. The minimum and maximum weight of eggs was 1.2 and 3 Kg, respectively and the minimum and maximum number of eggs per gram was 71 and 124 eggs, respectively. The maximum condition factor for spawners was 0.76 and the minimum condition factor was 0.39 (average 0.51). The age of spawners ranged from 8 to 14 years. Statistical analysis of data recorded other than GV showed no significant differences between the parameters measured in A. persicus breeders used for artificial breeding and those not used in artificial breeding. Considering the importance of the pathological state of spawners used for breeding the frequency and cause for mortality in incubators as well as vniro tanks and so also the condition of sturgeon fry in earthen ponds in terms of bacterial and parasitical infection and the effects of these infections on survival rate and growth of fry and the quality control of spawners and fry were carried out in the Shahid Beheshti and Yousefpour hatcheries. The 149 sturgeon breeders studied (109 A. persicus, 36 A. stellatus, 3 A. nudiventris and 1 H. huso) at the Shahid Beheshti hatchery showed 8 kinds of parasitical worms. The results obtained from this study indicate that A. stellatus breeders showed the maximum number of digestive tract parasitical worms. Cucullanus spherorocephalus with a prevalence rate of 84.26 % showed the highest abundance and Corynosoma strumosum and Eubothrium asipenserinum with a prevalence rate of 0.93 % showed the minimum abundance in A. persicus spawners. On the basis of this study the digestive tract parasite Skrjabinopsolus semiarmatus with a prevalence rate of 77.78 % showed the maximum abundance and Amphilina foliacea and Eustrongylides excisus with a prevalence rate of 2.78 % showed the minimum abundance in A. stellatus spawners. The relationship between weight of spawners and weight of eggs harvested was studied with prevalence of digestive tract parasites. No parasitical and bacterial infection was observed in the 100 sturgeon larvae examined. Examination of sturgeon fingerings in the two hatcheries in the middle and again at the end of the rearing period showed no signs of bacterial and fungal infections. In the parasitical examination of sturgeon fingerlings studied Triclodina and Diplostomum were identified. Percentage incidences of Diplostomum in the Shahid Beheshti hatchery was 4.97 % and that in the Dr. Yousefpour hatchery was 10.09 %. The percentage incidences of Triclodina in the Shahid Beheshti and Yousefpour hatcheries were 46.68 % and 70.76 %, respectively. However no Diplostomum infections were observed in the 113 A. stellatus specimens examined in the Shahid Beheshti hatchery. Results obtained from this study indicate that A. stellatus specimens from the Dr. Yousefpour hatchery showed higher prevalence to Triclodina as well as Diplostomum infection as compared to the A. stellatus studied in the Shahid Beheshti hatchery. Monitoring the hygienic conditions in the two hatcheris under study during mid-rearing period and at the end of the rearing period revealed an increase in prevalence rate and intensity of Triclodina and Diplostomum infection at the end of the rearing period. Examination of pectoral fin of sturgeon fingerlings indicated higher incidences of pectoral fin deformities in fingerlings studied in the Shahid Beheshti hatchery than in the Dr. Yousefpour hatchery. In 2002 release of fingerlings started on 15.06.2002 at the Shahid Beheshti hatchery and on 8.9.2002 at the Dr. Yousefpour hatchery. Totally 4809554 fingerlings were released into the Sepidrud River. Totally 2889462 fingerlings were released from 31 earthen ponds (2 hectares) at the Shahid Beheshti hatchery starting from 17.6 2002 to 21.7.2002 out of which 2563159 fingerlings belonged to A. persicus that comprised 88.7 % of the total abundance with a mean weight of 5 g and mean length of 10.9 cm, 324789 fingerlings belonged to A. stellatus that comprised 11.2 % of the total abundance with a mean weight of 6.9 g and mean length of 16.2 cm, 1514 fingerlings belonged to A. nudiventris comprising 0.1 % of the total abundance with a mean weight of 12.9 g and a mean length of 14.5 cm. Out of the total number of fingerlings released 74.5 % of A. persicus, 98 % of A. stellatus and 100 % of A. nudiventris were above 3 g per fish in weight. The survival rate of reared fishes was 45.47 % for A. persicus 0.89 % for A. nudiventris. As the exact number of A. stellatus larvae introduced to the rearing ponds was not known the survival rate for this species was not estimated. In A. persicus specific growth rate (3.36) was very low while condition factor (0.41) was moderate. In A. nudiventris growth rate (3.37) and condition factor (0.41) were moderate. About 1920092 fingerlings were released from the Dr. Yousefpour hatchery starting from 15.06.2003 to 08.09.2003 of which 1895948 fingerlings belonged to A. persicus that comprised 98.8 % of the total number with a mean weight of 3.4 g and a mean length of 9.4 cm, 24144 fingerlings belonged to A. stellatus comprising 1.3 % of the total number with a mean weight of 7.5 g and a mean length of 11.7 cm Out of the total number of fingerlings released 43.7 % of A. persicus and 31.7 % of A. stellatus fingerlings were above 3 g per fish in weight. The survival rates of the reared fishes were 24.2 % for A. persicus and 14.6 % for A. stellatus. In A. persicus the growth rate (2.99) was low while condition factor (0.38) was moderate. In A. stellatus the growth rate (3.06) and condition factor (0.30) were low. Significant differences (P〈0.05) were observed on comparing condition factor (F=4.573), survival rates (F=20.971) and rearing period (F=5.038) in A. persicus in the two hatcheries. Therefore A. persicus fingerlings released from the Shahid Beheshti hatchery showed better survival rates and attained the maximum mean weights in a shorter rearing period, whereas fingerlings released from Dr. Yousefpour hatchery were in a better state regarding condition factor.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: Four experiments were conducted to study of production meat in reared beluga (Huso huso) with different diets. In the first experiment, A 19-week feeding trial was conducted to evaluate dehulled soybean meal (DHSM) as a fish meal (FM) replacer in juvenile beluga, of initial body weight 8.25 ± 0.08 g (mean ± SD) in triplicate groups, fed six isoenergetic (20.1 mJ kg-1) and isoproteic (45% crude protein) diets, resulting in 5%, 10%, 15%, 20% and 25% of fish meal protein being replaced by soybean protein. Growth performance was reduced significantly with the increasing of DHSM in the diets in the present study. In the next stage, triplicate groups of 315 fish averaging 300.25 ± 10.28 g (mean ± SD) were fed one of seven experimental diets for 14 weeks. Weight gain (WG), specific growth rate (SGR), feed effeciency (FE), protein efficiency of retio (PER) of fish fed 5%, 10% and 15% of soybean protein diets were significantly higher than those of fish fed 20%, 25% and 30% diets. Whole body protein, lipid, moisture content were unaffected among different treatments (P 〉 0.05). In the second experiment, A 2 × 4 factorial design was used to evaluate the dietary lysine and to determine the optimum dietary L-carnitine in sub-yearling beluga, reared in the indoor system. Twelve experimental diets were formulated and prepared to contain four lysine levels (0.75, 1.5, 2.25 and 4% diet) and two L-carnitine levels (300 and 600 mg/kg diet) at each lysine level. Fish averaging 23 ± 0.5 (mean±SD) were fed one of the experimental diets for 10 weeks. At the end of the experimental period, there were significant lysine and Lcarnitine effects (P 〈0.05) on growth performance and feed conversation ratio (FCR). These results may indicate that, weight gain (WG), FCR and protein efficiency ratio (PER) in fish fed diet containing 3% lysine and 600 mg L-carnitine/kg diet were significantly higher than those of fish fed control diet (P 〈 0.05). There were no significan dietary lysine and L-carnitine effects on glucose, cholesterol and haemoglobin (Hb) concentration, of fish fed different levels of lysine with 300 mg L-carnitine/kg diet, however, Hb concentration in fish fed diet containing 2.25% lysine and 600 mg L-carnitine/kg diet were significantly higher than those of fish fed control diet (P 〈 0.05). These results may indicate that the optimum lysine and the L-carnitine levels could be 2.25-3% and 600 mg L-carnitine, respectively in begga (8-300 4g), based on growth performance, feed utilization and hematological parameters. In the thired experiment, a study was conducted to evaluate the effects of dietary betafine and metionine interaction on the growth, feed efficiency, carcass composition and hematological index in juvenile beluga. Thirteen diets were formulated to contain four dietary metionine levels (0.5, 1, 1.5 and 2%), betafine (0.5, 1, 1.5 and 2%) with equal ratio of metionine and betafine (0.5: 0.5, 1: 1, 1.5: 1.5 and 2: 2% diet) were fed to juvenile beluga (23± 0.5 g) in triplicate groups for 12 weeks in a indoor system. The results showed that no significant (P〉 0.05) differences were found in growth performance and feed utilization among the dietary betafine and metionine concentrations in beluga. Hb concentration of fish fed control, 1 and 1.5% metionine were significantly higher than those of fish fed the other diets. FCR of fish was significantly improved by dietary metionine and betafine. FCR was lower (P 〈 0.05) in fish fed equal ratio of metionine and betafine (2: 2) diets than those in fish fed control diet. Based on above results, it is recommended that the diet for juvenile beluga, Huso huso (8-300g), should contain equal ratio of metionine and betafine (1.5: 1.5) diet, corresponding to 5.95 g/100 g of dietary protein for optimum growth, efficient feed utilization and whole-body protein content. A 17-week feeding trial was carried out to evaluate the effects of dietary L-carnitine level in beluga, Huso huso. A total of fish averaging 1247 ± 15.6 g (mean ± SD) were randomly distributed into 18 fibreglass tanks, and each tank holding 10 fish was then randomly assigned to one of three replicates of six diets with 50, 150, 350, 650, 950 and 1250 mg L-carnitine kg-1 diet. At the end of 17 weeks of feeding trial, average weight gain (WG), feed efficiency (FE), protein efficiency ratio (PER) and condition factor (CF) of fish fed 350 mg kg-1 diet were significantly (P 〈 0.05) higher than those of fish fed 50, 150, 950 and 1250 mg kg-1 diets. WG, FE, PER and CF of beluga fed 650 mg kg-1 diet were also significantly higher than those of fish fed 50, 950 and 1250 mg kg-1 diets. Whole body and muscle protein were significantly improved by the elevation of dietary L-carnitine level up to 350 mg kg-1. Liver superoxide dismutase and glutathione peroxidase activities of fish fed 350 and 650 mg kg _1 diets were significantly higher than those of fish fed 50, 950 and 1250 mg kg-1 diets. The dietary Lcarnitine level of 350–650 mg kg-1 diet could improve growth performance, feed utilization, protein-sparing effects of lipid, antioxidant defence system and reproductive success. Polynomial regression of WG suggested that the optimum dietary L-carnitine level was 480 mg kg-1 diet. Therefore, these results may indicate that the optimum dietary L-carnitine could be higher than 350 but 〈650 mg kg-1 diet in beluga reared in intensive culture conditions.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: This study was carried out on 16 Sturgeon spawner(6 ship and 10 persian sturgeon) which were operated in shahid Dr. beheshti Rearing and Propagation Complex during 2001, 2002 and 2003. surgery performed on 16 spawners (6 ship sturgeon and 10 persian sturgeon). operation fulfilled in 3 ways: 1- without anesthesia 2- anesthesia by injection of Chanazin 2%(4 to 10 mg for per kilogram of fish body weight) 3- anesthesia by replacing fish in clove powder solution. In the surgery operation without anesthesia, the fish maintained by three persons and the eggs removed. In the case of applying anesthesia, 2% Chanazin, with commercial name Rompun(20 mg/ml), 4- 10 mg for per kilogram of body weight injected, but the rate of clove Powder application was 150 200 mg/l.surgery carried out by Kosarva method(making slight cut on Ventral area stitching). The cut length was 6-8 cm. The cut site stitched by Kapron unabsorbable thread and single knot with 6 to 7 mm distance.The mean weight of female spawners of ship(Acipenser nudiventris) was 35.3 ± 8.3 kg(n=6) which 3.9 ± 0.89 kg caviar, removed on average(11% of total body weight). The mean weight of female spawners in Persian sturgeon(Acipenser persicus) was 23.6 ± 3.2 kg(n=10) that the mean rate of caviar removed was 2.7 ± 0.62 kg(11.4% of total body weight). Investigation on reared spawner of ship(Acipenser nudiventris, n=16) and Persian sturgeon (Acipenser persicus,n=60) without surgical operation showed that the average body weight of spawners was 43.7 ± 8.8 kg and 28.9 ± 6.4 kg and the mean rate of caviar removal was6.4 ± 1.7 kg (15.7% of total body weight) and 4.4 ± 1.3 kg (15.4% of total body weight) respectively. During 2001, surgical operation performed on 8 spawners(5 ship and 3 persian sturgeon) which one Persian sturgeon and 2 ship after one day, one ship after 3 days and two ship after 32 days and 105 days and 2 persian sturgeon after 91 and 136 days were died. During 2002, totally five Persian sturgeon were operated which all of them died after 46,116,130,132 and 157 days. During 2003, 3 spawners(2 persian sturgeon and one ship) were operated which two Persian sturgeon died after 23 and 59 days and one ship spawnerdied after 72 days. This mortality can be due to not feeding of formulated food and even live food by the wild spawners after surgery. Also, other factors can be mentioned, such as existence of otter in the ponds with spawners are kept, breaking of swim bladder during egg sampling in catch stations & hatcheries small area for maintaining spawners after surgery and not tolerating of surgical operation by some spawners. It should be mentioned that surgery point has been fully improved in the spawners that survived more than 40 days after surgery. The results of the study indicated that removal of caviar from wild spawners is possible, but maintaining them in freshwater to remove caviar again, can be problematic. So, the surgery for caviar removal & removing of caviar for second time in following years should be carried out only on reared spawners.

Description: Iranian Fisheries Science Research Institute

Description: Published

Description: Artemia has been widely used in aquaculture as a suitable live food. The presence of highly unsaturated fatty acids is a key factor that determines the nutritional value and marketing of Artemia for shrimp, marine larvae, sturgeon and ornamental fish industries. To determine the variation in nutritional content in cysts, decapsulated cysts and nauplii of Artemia from three different biotopes of Iran, were tested for their protein, lipid, energy, and fatty acid profiles, particularly essential fatty acids. The cysts collected from Urmia, Maharlou and Meighan lakes, were rinsed, processed, decapsulated, hatched and then analyzed for proximate and fatty acid composition using standard methods. Statistical comparisons of the results revealed significant differences not only in proximate composition but also in fatty acid contents (p〈0.05). The highest mean (±SD) level of protein (60.5±3.3 %), lipid (18.60±1.1%) and energy contents (5448.3±10.4 Kcal/kg) were observed in Instar I nauplii hatched from Urmia Lake cysts, Instar I nauplii hatched from Maharlou Lake cyst and Instar I nauplii hatched from Urmia Lake decapsulated cyst, respectively. The highest content of DHA (0.78 mg/g DW) was observed in nauplii of cysts from Urmia Lake whereas, it was around zero in other samples. The highest level of EPA (24.24 mg/g DW) was measured in nauplii from Maharlou Lake decapsulated cysts and the lowest (0.24 mg/g DW) was observed in Urmia lake cysts. The results revealed that the nauplii from decapsulated cysts of Maharlou Lake Artemia contained significantly higher levels of EPA and n-3 HUFA compared to others. Therefore, it is recommended to use it in aquatic larviculture.

Description: Published

Description: In this study, 180 Beluga (Huso huso) weighing 120110g each with a stocking density of 12 fish per tank were adapted with synthetic diet and then fed with different levels of AFBI (0, 25, 50,75 & 100pplpikg of diets) under controlled conditions (T=1 8±2°C, DO=7.3ppm). The fish were fed 3% of their body weight four times a day for three months. Prevalence of skin lesions evaluated through clinical observations monthly. With regard to toxin concentration and time of exposure to AFBi in experimental fish, different degree of skin lesions (simple hemorrhage to progressive wounds) were observed in different parts of body especially in vent, caudal peduncle, fins, and head. "Yellow sores" on head and trunk regions were considerable and led to deterioration of appearance. Prevalence of skin lesion in different treatments was 8•m53.3%. After feeding with toxic diets was stopped, 16.w24% healing was obsenTed in the fish.

Description: Published

Description: In the present study, the impacts of various concentrations of Aflatoxin B1 (AFB1) on Beluga, Huso huso, under controlled conditions were investigated. Belugas (120±10g) were fed on diets containing 0, 25, 50, 75, and 100 ppb AFB1/kg of diet for 3 months. Results showed various levels of AFB1 do not significantly affect the specific growth ratio (SGR) (P〈0.05) of fish in different treatments. However, weight gain and food conversion ratio (FCR) were varied significantly (P〈0.05 between control and treatments with diets contaminated with 75 and 100ppb AFB1/kg after 90 days). The increase AFB1 level of did not affect on the percent of survival rate(SR) and no mortality was observed in treatments (SR=100%) suggesting that various AFB1 levels under experimental conditions of the present study affect some growth factors, such as, weight gain and FCR but have no significant impact on SR and SGR. Histopathological studies showed that different level of AFB1 can cause broad range of change in liver tissue, including progressive fat deposition, hepatocyte degeneration and necrosis, particularly at concentration of 75 and 100ppb AFB1/kg of diets after 60 days.

Description: Published

Description: To improve Persian sturgeon nutrition and determine its nutritional requirements, a growth trial was conducted to measure optimum dietary protein to energy ratio in Persian sturgeon sub-yearlings. Four diets: H (P/E=21.33mg/kJ), N (P/E=20.24mg/kJ), L (P/E=19.22 mg/kJ) and M(P/E=18.26mg/kJ) were used in the experiment. Triplicate groups of fish were kept in 500L fiberglass tanks under homogenous culture conditions (dissolved oxygen, light and water flow rate) and fed with the experimental diets. Fish were fed to satiation four times per day during 130 one fourth ¬ days of experiment when the average water temperature and dissolved oxygen were 12.82 plus or minus 1.48 degree C and 9.55 plus or minus 0.18mg/l respectively. Fish in all treatments grew fast and efficiently utilized the diets. Growth rate, FE, GR, SGR and PER increased with decreasing dietary protein to energy ratios. A higher growth was observed in the fishes fed with lower P/E ratios. Food intake and fatness coefficient increased with increasing dietary energy and decreasing P/E ratios. There were no significant differences in feeding efficiency (FE) and protein efficiency ratio (PER) in fish fed with diet N (high carbohydrate and low lipid content) and diet L (low carbohydrate and high lipid content). We conclude that the Persian sturgeon is able to use lipids and carbohydrates as non-protein sources of energy. The results of the present study demonstrated that the protein content and P/E ratio for optimum growth and efficient protein utilization in Persian sturgeon is 40% and 18.3-19.2mg protein/kJ energy, respectively.

Description: Published