JOURNAL OF FISHERIES SCIENCE AND TECHNOLOGY (JFST)
Year:2015 | Volume:4 | Issue:2|Papers Count:10

The effect of delayed icing of common carp (Cyprinuscarpio) on the quality of the produced surimi was in vestigated.The fish were divided into three groups after trapping; one group was kept in ice immediately, while the second and third groups were kept in ice after 3 and 6 hours delay, respectively. The produced surimi from these fish groups were stored in refrigerator for 15 days, after which were tested chemically (TBA, TVB-N, pH) and micro bially (total bacteria count) every 3 days.Results showed that TBA in 6 hours delay treatment was significantly higher than that in control and 3 hours delay. TBA levels in control plots increased until day 12 and then decreased, while in 6 hours delay an increasing trend until the end of the period was recorded. The TVB-N in the ice delayed samples exceeded the allowable level after 3 days storage, while in control treatment it exceeded the limit at the end of the period. PH values in different treatments showed no significant differences.The lowest pH value (7.03) was recorded in 6 hours delay treatment and the highest pH value (8.37) was recorded in the control at the end of the storage period. The total bacterial counts (TVC) increased in all treatments during the period and the maximum of TVC (4.68 log cfu / g) was recorded in 6-hour delay samples. Based on these results, the delayed icing of common carp lead to loss of produced surimi quality.

The effects of dietary nucleotide at 5 levels of 0.0% (Control), 0.15%, 0.25%, 0.35% and 0.5% on the body composition and fatty acids of the grouper, Epinephelus coioides, with initial weight of 10.70±0.29 g was investigated for a period of 10 weeks. The results indicated improved growth parameters upon adding nucleotide.The best value of growth parameters were observed at nucleotide level of 0.35% that statistically showed higher values for final weight, weight gain and condition factor than other treatments (P<0.05).There was no significant difference in survival (P>0.05). The 0.35% nucleotide level also resulted in a better fatty acids profile, including EPA, EPA+DHA and n-3 than the control. However, 0.5% nucleotide showed significantly higher saturated fatty acids, MUFA and n3/n6 than the control.No significant differences were observed in arachidonic acid and DHA among the treatments (P>0.05). Chemical analysis showed the highest muscle protein in 0.15% and the highest muscle fat in 0.15 and 0.25 treatments, which were significantly higher (P<0.05) than the control group. The results of this study showed that dietary nucleotide has positive effects on growth performance and fatty acid profile of the grouper and the 0.35% level had a better performance.

Thegro wth performance of cyprinids larvae (Cyprinuscarpio, Hypophthalmichthysnobilisand Ctenopharyngodonidella) fed with the nauplii fromdifferentArtemiaspecies, including A. parthenogenetica, A. fransiscanaand A. urmiana as well as a probiotic mixture (Bacillus subtilis and B. licheniformis) was investigated. Fish larvae (100±15 mg) were allocated into 54 circular fiberglass tanks filled with 10 liters of water (density of 5 fish per liter) and fed for 4 weeks with the designated diets. At the end of the feeding trial, feed and growth indices [final weight, specific growth rate (SGR), condition factor (CF) and food efficiency] and body composition (crude protein, crude lipid, ash and moisture) were assessed. Significant differences were observed in feed and growth parameters especially in terms of specific growth rate and feed efficiency (P<0.05). The highest and lowest growth and feeding efficiency were observed in C. idella fed with A. parthenogeneticanauplii and H.nobilis fed with A. urmiananauplii, respectively. Subsequently, elevated growth performance (final weight, final length and SGR) was observed in C. idella fed with nauplii of A. parthenogenetica and probiotic compared to other group (P<0.05).

The effects of mucal proteins of sea anemone, Stichodactyla haddoni, on different stages of embryonic development of zebra fish (D. rerio) were examined. The sea anemone samples were collected from the intertidal areas of the Hormuz Island (Persian Gulf), and were frozen at -160oC. Protein and peptide components were extracted by 100% methanol. Following the total protein assessment by ELISA, three concentrations (2.1, 3.7 and 7.4 mg/ml distil water) were prepared. From each concentration, 2 ml was added to the microplates containing 150 zebra fish eggs each, with 2 replications; microplates with normal aquarium water was also used as control group. The eggs were incubated for 72 hrs and the process of embryonic development was observed every 6 to 12 hours. Results showed that the embryonic development was normal in the control group, while the eggs treated with 3.7 and 7.4 mg/ml of mucal proteins degenerated and blackened in less than 12 hours. Also a delay in the phase of growth in embryonic development was observed in the group with 1.2 mg/ml of protein. Our results showed that the mucal proteins from this sea anemone can affect embryonic development rapidly, causing delayed growth at low concentration, and cell lysis and embryonic degeneration at high concentrations.

The aim of this study, in the first step, was to recover the protein content in wastewater of fish meal factories using chitosan, chitosan nanoparticles and chitosan-aluminum sulphate composition. In the second step, the extracted protein was assessed for its essential amino acids profile. Also, the reduced amount of proteins in the waste water was evaluated by measuring different parameters such as turbidity, pH, COD. Finally, chitosan nanoparticles characteristics were investigated using atomic force microscopy. Results showed that turbidity, COD and soluble protein significantly decreased upon adding different concentrations of chitosan, nanoparticle of chitosan and chitosan-alum (p<0.05). The maximum protein recovery was related to chitosan-alum composition and chitosan nanoparticles with no significant difference between these two treatments. Evaluation of recovered protein in term of amino acids profiles showed that there were essential amino acids such as histidine, lysine, methionine and phenylalanine in protein of fish meal wastewater.

The effect of different levels of betaine and tryptophan on growth and resistance to salinities in the Caspian roach was investigated. Fish (1.90±0.04 g body weight) were divided into 9 groups (4 treatments groups containing betaine (0.5 and 1), tryptophan (0.25 and 0.5), betaine and tryptophan mixtures (0.25- 0.5, 0.25, -1, 0.5- 0.5 and 0.5- 1), and control group). After recording the growth factors, the fish were exposed to salinities (12, 16 and 20 ppt) and clinical symptoms and mortality rate were recorded. No mortality occurred in 12 ppt salinity. At 16 ppt, the lowest mortality (16.66%) was recorded in the treatment containing 1% betaine and 0.5% tryptophan, while the highest mortalty (59.98%) occurred in the control group. At 20 ppt salinity, 100% mortality occurred within 6 hours in the control, while in the other treatments 100%-mortality occurred after 24 hours. Behavioral symptoms, such as jerky movements, ataxia, increased respiratory rate, were more prominent in higher salinities. Tryptophan did not reduce food consumption meaningfully.Increaesd food consumption as the result of betaine did not show significant effect on the fish growth rate.

The antibiotic properties of eight cyanobacteria (blue-green algae) species from Anzali Wetland was investigated on several bacterial species through vacuum distillation and simple mechanical methods. The result showed that Anabaena sp., A. variabilis, A. flos-aquae and Aphanizomenonflos-aquaehad negative effect on the growth of Staphylococcus aureusandA. flos-aquaeand A. oscillaroideshad negative effects on the growth of E. coli. The growth of Candida albicans yeast was greatly reduced by Aphanizomenonflos-aquae, A. variabilis, and A. oscillaroides.Among the investigated algae only A. oscillaroides could reduce the growth of Pseudomonassp.

A 27 day study was undertaken to evaluate the effects of aqueous extracts of Hypericumperforatum on hemato-serological parameters and survival of rainbow trout (Oncorhynchusmikiss) under thermal stress (20±2oC). A total of 360 rainbow trout (97.2±1.6g) were divided randomly into four groups and immersed in different concentrations (0, 250, 500 and 750 ppm) (T0, T25, T50 and T75) of aqueous extracts of H. perforatum. The blood samples were collected on day 12 and 27 and hemato-serological parameters were determined. In stage 1, the total red blood cell, hemoglobin and hematocrit didn’t show a significant difference among controls and treatments but in stage 2, those parameters were significantly increased in T50 and T75 compared to T0 and T25. The total white blood cell, lymphocytes, total protein, albumin, and total IgM showed a significant increase in treatments compared to control but the results in the neutrophils was opposit. The MCV and MCH didn’t significantly change in two stages but the MCHC of T75 were significantly higher than T0 and T25. The glucose of T50 and T75 were significantly lower than T0 and T25. The hepatic enzymes, ALT and AST of T75 significantly increased compared to other groups in stage2. The highest and lowest survival rates were observed in T50 and T0, respectively. Based on the results, it seems that Hypericum perforatum could control the effects of stress and increase the survival rate of rainbow trout when exposed to chronic heat stress.

Effects of feeding Artemianauplii enriched with PHB (0, 0.1, 0.3 and 1 g/L concentration) on the growth performance, body composition, digestive enzyme activity and hindgut bacterial community in the Persian sturgeon hatchlings were investigated. PHB treatment significantly (p≤ 0.05) decreased growth performances of the hatchlings. The PHB also significantly increased the total saturated fatty acids (SFA) and n6, but decreased the total MUFAs, C18: 3n3, n3 and n3/n6. PHB also altered digestive enzyme by significantly decreasing the total protease, amylase, and lipase. Based on molecular analysis, PHB changed the microbial community in the hindgut of the hatchlings where less dominant bands were observed. Our results show that PHB has negative effects on the Persian sturgeon hatchlings. Further studies are needed to find out the optimal concentration of PHB to apply in early larval rearing of sturgeon.

This study was to up-grade a model leading to a more accurate prediction of growth and body composition in rainbow trout. Based on an earlier model (FGS2) predicting fat and protein retention in relation to feed level and composition, we tested the model using the latest nutritional experiment conducted on rainbow trout. The result showed that our model predicted more accurately by up-grading digestibility estimates for protein, fat and carbohydrate and also maintenance and feeding metabolism than that of FGS2. A more accurate prediction observed in relation to wet weight gain and protein retention can be resulted from the correction of digestibility estimates, calculation of heat loss based on feed composition and changing of routine metabolism coefficient.