نشریه علوم و فنون شیلات
سال سوم شماره 1 (پیاپی 6، بهار 1393)

The probiotic effects of Saccharomyces cerevisiae and Aspergillus niger on the feeding efficiency, body composition, ammonia excretion, blood serum enzymes and the intestinal microbiota of juvenile beluga, Huso huso was investigated. The fish (31.8±2.81g) were randomly allocated into 12 oval tanks at a density of 30 individuals per tank with three replicates for each treatment,. The fish were fed either a basal diet (as control) or the diet supplemented with S. cerevisiae and A. niger (2×106, 4×106 and 6×106 cells g-1) for 8 weeks. The results indicated that the probiotic supplemented diet at 6×106 (cells g-1) significantly improved FCR and other nutritional indicators compared to the control treatment (p

The effect of six diets including Scenedesmus quadricauda), manure (cattleꚋꖶ, 1:1 ratio), vegetable (spinachꖪ岾犊睞, 1:1:1 ratio), algae늈, vegetable늈, and manure늈 were examined on culture of freshwater copepod, Acanthocyclopsrobustus, under the experimental conditions of 23±1ºC, 12 hours dark: 12 hours light photoperiod, and light intensity of 60 µmol photons/m2/s. The maximum population density (1282.6±163.7 individuals/L), maximum specific growth rate (SGR) (0.17±0.0 /day) and minimum doubling time (Dt) (4.0±0.1 days) were obtained when A. robustus fed on algae늈. The nauplii production was 727.3±42.4 (±SE), 272.0±23.5, 267.6±17.7, 147.0±18.2, 33.6±3.8 and 25.0±7.1 ind./L and copepodit production was 311.3±26.8, 124.3±11.1, 183.0±13.0, 59.0±7.1, 14.3±8.1, and 17.6±3.6 ind./L in algae, algae늈, vegetable, vegetable늈, manure늈, and manure, respectively. Correspondingly, the adult production was 208.5±26.8, 51.6±16.5, 192.7±23.7, 91.7±28.4, 8.7±5.4 and 8.7±3.6 ind./L, respectively. The maximum body length (663.8±29.1 µm) and width (526.2±23.7 µm) of A. robustus were recorded when fed with vegetable늈 and vegetable, respectively. The number of nauplii, copepodit, adults, length and width were significantly correlated with EC, BOD and COD. According to results, the A. robustus has suitable potential culture on algal and non-algal diets based on production, growth, body size, BOD and COD, but the better performance obtain on algae늈 and vegetable.

The effect of an imported and an indigenous probiotics on growth, feeding parameters and survival of whiteleg shrimp (Litopenaeus vannamei) postlarvae (50±6.54 mg) was investigated during 60 days feeding trial. The shrimp was fed three times daily at 7 percent of biomass with three feeds supplemented with probiotics (an imported and an indigenous ones, and an equal amount of both (, plus a blank feed as control. Probiotic supplemented feed brought about a higher final weight and final length, specific growth rate, better feed conversion ratio and a higher resistance to stress (p

The effect of edible chitosan and chitosan-gelatin coating on the quality of fish finger from silver carp during refrigeration was assessed. Fish fingers were immersed separately in coating solutions of chitosan 1% and chitosan 1%-gelatin 4%, packed and stored in refrigerator (4±1˚C) for 30 days, then their chemical (TVB-N, PV, TBA) and microbiological characteristics (TVC and PTC) were analysed. Total volatile basic nitrogen value of coated sample with chitosan was lowest while there was no significant difference between the thiobarbituric acid value of coated treatments (p

The effect of cadmium on hematological and biochemical indices of silver carp (Hypophthalmichthys molitrix) exposed to subacute (0.65ppm) and acute (3.25ppm) concentrations for 96-h test period was assessed. The results showed that Hb, Hct, RBC and MCV significantly decreased in low concentration of cadmium (p

A 12-week feeding trial was carried out in 500 L fiberglass tanks to evaluate the effect of dietary choline at 0, 2, 4, and 8 g kg -1 levels on growth rate, body composition and total liver lipid of juvenile Acipenser baerii (37.67±0.67 g). A semi purified basal diet was formulated using vitamin free casein and wheat gluten as a protein source, a mixture of animal and plant oils as a lipid source and dextrin as a carbohydrate source. Four isonitrogenous (40% protein) and isoenergetic (18 MJ kg-1) diets were prepared and fed to the fish three times daily to apparent satiation. Weight gain, feed conversion ratio (FCR), specific growth rate (SGR) and protein efficiency ratio (PER) were significantly affected by dietary choline (p0.05). Total lipid of liver and plasma, plasma cholesterol, triglyceride and phospholipids levels showed an increasing trend with increasing levels of dietary choline, but not significantly different among treatments (p>0.05). Based on the results, we recommend adding a 1.5 gkg-1 choline to commercial diet of juvenile Acipenser baerii.

Length-weight relationships and fecundity of 93 individual female Acipenser persicus broodstocks were investigated. The specimens were caught during 2001-2005 from Golestan, Mazandaran and Guilan provinces along the southern coast of the Caspian Sea. Total length and weight of each fish was measured to the nearest 1cm and 100 g, respectively. Age determination was carried out by using transects of the first ray of pectoral fin. The absolute fecundity was assessed by egg count per weight unit of all eggs existed in the body. The specimens were from 13 to 20 years old, of which the 16 years old had the highest proportion with 23.7%. Range of total length and weight were 132.5 to 211 cm and 14 to 42 kg, respectively. Mean absolute fecundity was estimated 267810 ± 92570. Total length, weight and absolute fecundity of fish increased with age in all cases, showed a significant positive correlation (p