JOURNAL OF FISHERIES SCIENCE AND TECHNOLOGY (JFST)
Year:2013 | Volume:1 | Issue:1|Papers Count:6

In this study, the effect of fructooligosaccharide as a prebiotic on the growth and density of lactobacillus in intestine of stellate (Acipenser stellatus) has been investigated. To do this, 90 individuals of stellate fingerlings (ten in each replications) were prepared with an average weight of 30.16±0.14 gr from International Sturgeon Research Institute. This study was carried out in a completely randomized design with three replications in fiberglass tanks with 2000 liters volume. They were fed with feed containing 0, 1 and 2 percents of fructooligosaccharide (Raftilos P95, Sigma Company).Results indicated that feed with one percent fructooligosaccharide had a significant effect (P<0.05) on weight gain, SGR, FCR, FE, PER and HI.The number of colonies regarding to lactobacillus showed a significant increase compared to the control (in one percent fructooligosaccharide).Results indicated that fructooligosaccharide as a prebiotic (in level of one percent in feed) caused good growth capabilities and feed efficiency through increasing the density of lactobacillus in intestine.

Uncoated fish burgers were produced in order to expand the variety of products from Silver carp, Hypophthalmichthies molitrix, and increase the consumption of this fish species. On the other hand in order to compare the effect of ascorbic acid and vacuum packaging on rancidity inhibition and microbial quality, 3 different treatments of fish burger were produced: 1. Burger with common packaging (Control group), 2. Burger with vacuum packaging 3. Burger with 500 ppm ascorbic acid in common packaging. All the treatments were stored in -18oC for 6 months after freezing by a spiral freezer in -35oC. Chemical, microbiological and sensory evaluations were determined from time 0 and after that monthly until the 6th month. The TVB-N value increased during the storage period but it never passed out of the standard range. The TBA value increased in all treatments but in ascorbic acid treatment it was significantly lower than the other two groups. The pH amounts during storage period decreased in all treatments homogeneously. Microbial counts in all treatments and especially in vacuum packed burgers decreased during the storage period. Organoleptic test demonstrated the preference of burgers treated by ascorbic acid. The shelf life of control group and burgers with vacuum packaging was determined 3 months at least. The shelf life of treated burgers with ascorbic acid was determined about 6 months specially based on the TBA index and sensory evaluation. Vacuum packaging was more effective to protect burgers of chemical and microbial changes compared to common packaging.

Twenty five individuals of Javelin grunter, Pomadasys kaakan, collected from Abadan (29o N and 48o E) and Bandar Abbas (27° N and 56° E) stations along the Persian Gulf, was analyzed for relationship between two populations of this species, using Amplified Fragment Length Polymorphism (AFLP). A total of 410 putative loci were detected by six primer combinations, 88 of which were polymorphic (21.46%). The proportion of polymorphic loci in the Abadan and Bandar Abbas stations was calculated 88.64 and 68.18%, respectively. Average of heterozygosity in the Abadan (0.330) was higher than Bandar Abbas (0.222), which may be correlated with the environmental and ecological conditions of these stations. Nei’s genetic distance for the two populations was estimated 0.112.The phylogenetic tree revealed a clear distinction line between the two populations, supporting that dispersal of eggs and larvae in the Persian Gulf is spatially restricted. Pattern of isolation by distance was observed in this species, indicating that the gene pool of P. kaakan in the Persian Gulf was not homogeneous. The results also showed that AFLP is a potent technique for genetic fingerprinting and species identification.

In order to determine effects of chicken and cattle manures in culture of Chlorococcum, an experiment was designed in six treatments including; 0.1, 0.4, 0.8 g/l of chicken manure and 0.1, 0.4, 0.8 g/l of cattle manure as completely randomize design with three replicates for 28 days.Results showed that the mean maximum density (87.1´105 cell/ml), specific growth rate (0.054 day-1), algal dry biomass (0.644 g/l), and chlorophyll a (9.42 mg/l) were obtained with 0.8 mg/l chicken manure. In order to compare performance of these manures with other culture media, second experiment with five treatments including; BBM (control) (Bold’s Basal Medium), BBM+soil extract, 0.8 g/l chicken manure, 0.8 g/l cattle manure and mixture of all treatment (BBM, BBM+soil extract, chicken manure and cattle manure) was designed as completely randomize design with three replicates for 15 days. Comparative results showed that BBM+ soil extract had highest algal density (11.6 x 106 cells/ml), highest algal dry biomass (0.81 mg/ml), maximum SGR (0.13 /day), highest chlorophyll a (10.15 mg/l) and minimum doubling time (4.97 days). In conclusion, performance of BBM+soil extract was better in terms of biomass and growth parameters of Chlorococcum.

This study was carried out to investigate the replacement of corn gluten meal in fish diets and the effects of it on blood biochemical and hematological parameters of common carp juvenile. Juvenile's carp with an average of 11.5±0.5g and 9±1cm weights and length respectively, were fed with experimental diets for 8 weeks. Diets with 31% crude protein and 3100 kcal kg-1 raw energy and alternative levels of 150, 270 and 490 (gr kg-1) and a control diet without corn gluten were made. At the end of the experiment, blood biochemical parameters including glucose, cholesterol, triglycerides, and also hemoglobin, hematocrit, white blood cells (WBC) and red blood cells (RBC) in juveniles fed the experimental diets showed a significant difference (P<0.05) compared to the control group. However, juveniles fed with diets 1 to 4 did not have any significant difference in the amount of total protein and MCV, MCH and MCH (P>0.05). Furthermore, with replacing the amounts of corn gluten in experimental diets, it was concluded that growth and nutritional factors in treatments compared with the control group decreased significantly (P<0.05). The results show that plant protein source of corn gluten meal is not a good alternative for fish meal and must be replaced in a level less than the one used in this research.

The main concern in fish transportation is about minimizing stress during transportation. In this study, the effects of zeolite and clove essence on rainbow trout survival and stress were investigated during transportation.4 treatments (each one includes 3 replicates) consisting of control, clove essence (25 mg/l), zeolite (14g/l) and clove essence (25mg/l)+(14g/l) were considered.156 fish (an average weight about 80±4.4 g) with a density of 130 kg/m3 were distributed randomly. Survival rates, cortisol and glucose levels were measured and analyzed (as indicators of stress) at zero, 6, 12 and 18 hours after the beginning of transportation. In the end, the results showed a significant difference in the survival rates as the control group had the lowest rates (P<0.05). There were no significant differences in cortisol and glucose levels at zero, 6 and 12 hours in different treatments, while the control group had the highest levels of cortisol and glucose at 18 hours (P<0.05). The results of this study showed that by using clove essence and zeolite in long-term transportation of rainbow trout (over than 12 hours), cortisol and glucose can be reduced, therefore reducing fish stress and mortality.