نشریه علوم و فنون شیلات
سال پنجم شماره 2 (پیاپی 15، تابستان 1395)

Biofilter is one of key components of recirculating aquaculture system (RAS) that affect initial investment, executing cast and success or unsuccess of system. Hence in this research, performance of barley straw, wood chip, sponge (as cheap and available media) and PVC pure pipe (to compare) based biofilters was surveyed in Common carp recirculating aquaculture system. To conduct this research 12 pilot recirculating aquaculture systems designed and 50 common carp individuals (mean weight: 4/8 g) were stocked in each system. After activation period (about 1 month), waste removal efficiency of biofilters and growth performance of Common carp were surveyed. Results indicated that sponge based biofilters had the best performance. Barley straw and wood chip based biofilters showed acceptable waste removal efficiency, while PVC pure pipe biofilters had poor performance. The highest feeding and growth performance of fish were observed in systems involved barley straw based biofilter. In conclusion barley straw, wood chip and sponge because of having low cast, being available, having relatively high specific surface area and showing acceptable waste removal efficiency, can be used in RAS and semi reuse systems.

In this study the effect of edible coating containing pomegranate peel extract (PPE) on the quality and shelf life of silver carp (Hypophthalmichthysmolitrix)fillet was investigated during refrigerated storage at 4 Cº. The total phenolic content (262.5 mg tannic acid/g sample) and DPPH free radical scavenging activity (87%) of PPE using methanol as solvent were determined. The mixture of edible coating was prepared (60% cool water 30% wheat flour 10% corn flour). Freshly fish fillet were assigned to three treatments: control (fillet without PPE); fillet treated with 5% PPE (T1) and 10% PPE (T2). Chemical (pH, and thiobarbituric acid (TBA)) and microbiological (total viable count (TVC) and psychrotrophic count (PTC)) analysis were used to evaluated the effect of PPE during refrigerated storage. The results show that addition of PPE considerably delayed lipid oxidation in silver carp fillet in T1 and T2 compared with control samples. According to microbiological assay, T1 and T2 samples on 12th of storage reached to maximum acceptability limit (7 log10 CFU/g) while it was happened on 9th of storage for control samples.

In this study, gelatin was first extracted by alkaline and acidic treatment including 0.19 N NaOH and 0.12 N acetic acid solution by ratio of skin of rainbow trout (Oncorhynchus mykiss (to solution of 1 to 7 and then heat treatment in 50 °C. Then, hydrolysed by alcalase enzyme for 4 hours with the ratio of enzyme to the substrate 1 to 100 and the degree of hydrolysis were measured after 4 hours. DPPH and ABTS free radical scavenging activity, as well as reducing power assay of gelatin hydrolysate were measured. The results showed that the degree of hydrolysis after 4 hours was 46/7%. Also the highest DPPH and ABTS free radical scavenging and reducing power at concentration of 10 mg/ml were 39/8%, 50/7%, and 0/123, respectively. The skin from fish filleting can be a suitable raw material for extraction of peptides with biological activities. The results showed that peptides derived from rainbow trout fish skin gelatin can be considered as a natural antioxidant.

The effect of human chorionic gonadotropin (hCG) on the immune response, biochemical parameters and serum enzymes in adult male and female goldfish during breeding season was investigated. Mature male and female received an intramuscular injection of human chorionic gonadotropin (hCG) 1/ IU hCG g/ BW and the control group was injected with saline solution. Twelve and 24 hours after hCG injection, blood samples were taken from broodstock and immune parameters (IgM, IgG, C3, C4), biochemical and enzymes (glucose, uric acid, urea, cholesterol, total protein, triglycerides, calcium, creatinine, albumin, HDL, LDL, AST and ALT) were measured. There were no significant changes in IgM levels in females between 12 and 24 hours after hCG injection compared to the control group (P>0.05). However, IgM level in male showed a gradual decrease in comparison to control fish (P

The effects of alcoholic extract from pomegranate (Punica granatum) peel on some hematological and biochemical parameters, including RBC, Hb, Hct, MCV, MCH, MCHC, WBC, TP, CHO, GLU, LDL, HDL, Glb, TG, GOT, GPT, Alb, ALK, LDH, and lysozyme activity of common carp )Cyprinus carpio( fingerlings (11.73 ± 1.81g) were studied for a period of 75 days. Treatments included different concentrations of ethanol extract of pomegranate peel (Zero: control, 50, 150, 300 and 600 mg/kg of diet). At the end of experiment, all fish were sedated for morphometric measurement and blood sampling. Significant increases in Hb, Hct and RBC in groups 300 and 600 mg/kg of diet were observed (P

Protein compounds were extracted from the mucus of sea anemone, Stichodactyla haddoni, and their effects on the gills of rainbow trout, Oncorhynchus mykisswere examined. Sea anemone samples were collected from the intertidal zone of the eastern coast of Hormuz Islandand frozen samples were transported to the laboratory. Then the mucus was extracted using of the PBS solvent and doses of 5, 10 and 24 mg/dry weight of total protein was injected into the tail vein of the fish. Upon the inactivation of fish, histopathological changes were examined using of the classical histological method. Lethal signs were observed in the gills, including aneurysm, hypertrophy of epithelial cells, lamella clubbing and deformation, subepithelial edema, lamella congestion in the interlamellar region and necrosis. The damages were more serious with increasing doses. The results showed that protein compositions of the mucus can cause numerous lesions in the gill tissue of fish, which act as an excretory, respiratory and ionic regulation tissue, the failure of which can lead to failure of fish’s vital functions that can be one of the reasons for the death of the hunted fish.
The results showed that the protein compositions of mucus can cause numerous lesions in the gill tissue, as an excretory, respiratory and ionic regulation tissue lead to failure of it functions that itself can be one of the reasons hunted fish death.

The effect of edible whey protein coating and dill (Anethum graveolens) essential oil on the quality and shelf-life of silver carp’s fillets, Hypophthalmichthys molitrix,during refrigeration storage was evaluated. Fillets were immersed in whey protein solution (10%), dill essential oil (5%) and a mixture of whey protein (10%) and dill essential oil (5%), then packed and stored in refrigerator (4˚C). Chemical (PV, TBA and TVB-N) and microbial (TVC and PTC) parameters were measured at 0, 3, 6, 9, 12, 15 and 18 days. The amount of peroxide value and thiobarbitoric acid significantly increased (P

In the current study, the effect of fresh water and different salinities of 15, 35 and 50 ppt on growth, feeding, body composition, glucose and cortisol in Asian sea bass (Lates calcarifer); were investigated. 180 fingerlings with average weight of 34.36±0.41 gram in 12 circular fiberglass tanks with 300 liter volumes were administered. Feedinng was done to satiation twice a day for 30 days. At the end of the experiment, biometry carried out and plasma and carcass samples were collected for estimating blood biochemical parameters and whole body composition. The obtained results showed that freshwater treatment had a significant difference in growth and feeding performance with other treatments (p

The present study was conducted to evaluate the effect of Lactobacillus plantarum (KC426951) isolated from the intestine of rainbow trout Guilan on growth factors, carcass composition and the intestinal bacterial flora of rainbow trout (Oncorhynchus mykiss) was conducted. Rainbow trout weighing 3.56±2.24 for 2 weeks were consistent with environmental rearing conditions. Five groups of fish were fed with diets containing 106 (T1), 107 (T2), 108 (T3), 109 (T4), 1010 (T5) cfu g-1 of L. plantarum and control group (T6) without diet containing probiotics were fed for 60 days. Results showed that final weight, final length, growth rate, percent weight were gained in treatment 2 the highest and 5 the lowest level in treated. Also, FCR lowest rates in treatment 2 and treatment 5 were accounted for most (p

The antimicrobial and physico-mechanical properties of fish gelatin-alginate film incorporated with oregano (Origanum vulgare L.) essential oil (OEO) were assessed. The blended films were prepared with 75% fish gelatin and 25% sodium alginate and OEO (0, 0.5, 1.0, 1.5%) was added to the film solutions. Results showed that adding 0.5% OEO into films improved tensile strength about 2.54 MPa compared to the control films. The incorporation of 1.5% essential oil decreased tensile strength and the elongation percentage by 3.16 MPa and 15.59%, respectively; water vapor permeability, viscosity and opacity also significantly declined (P