JOURNAL OF AQUACULTURE SCIENCES
Year:2018 | Volume:6 | Issue:8 |Papers Count:5

In the present study, the effect of enriched Dunaliella salina with zinc in 4 concentrations (0, 0.8, 1.6 and 3.2 mg L-1) was investigated on the growth, survival, and reproduction of Artemia parthenogenetica. Based on the results, on days 11, 17 and 21, the treatment of 3.2 mg L-1 and 0.8 mg L-1 had respectively the highest (7.07, 8.86 and 9.05 mm) and lowest (5.48, 7.06 and 7.25 mm) total length growth. In addition, survival rate decreased with increasing zinc content in the enrichment treatments and on days 11, 17 and 21. The lowest and highest survival rate was observed in the treatment of 3.2 and 0.8 mg L-1, respectively. To determine the reproductive efficiency of A. parthenogenetica, the number of nauplii, cysts produced per female, encysted embryos percentage and the reproductive period of each female were investigated. The highest reproductive period (13.6 days) and nauplii production (43.64 nauplii) were significantly observed in treatment 3.2 mg L-1 (P>0.05). Based on the results, the highest and lowest encysted embryos percentage in A. parthenogenetica were observed in treatment 0.8 and 3.2 mg L-1, respectively. The results also showed that D. salina are well-enriched with mineral zinc and there was a significant increase in the total length growth. However, with increasing levels of enrichment, there was no increase in survival rates and all reproductive performance.

The diversity among Artemia species proves the importance of morphologic and morphometeric investigations. Morphologic studies not only help in identification of close species, but also help to study the effects of environmental factors on the species and to identify the most influencing parameters on the morphologic changes. In this research investigated we investigated the simultaneous effect of salinity and temperature on morphologic changes in two populations of Artemia urmiana and Artemia parthenogenetica. The hatching of the cysts, feeding of nauplii and their culture were performed according to standard conditions. The Artemia from both populations were cultured under sailities 60, 120 and 180 g/L at 15, 24 and 30oC for a period of 30 days. Later the morpholpgic characteristics of adult Artemia were measured using a steriomicropscope equipped with drwing tube and digitizer. During this research over all 15 morphologic indices were measured at nine combinations of salinity and temperature. The results of analysis of variance showed that the average of measured parameters in both populations were higher at 24-60 treatment. Dendrogram of the cluster analysis based on morphologic characteristics seprated the two populations. In general Artemia urmiana and Artemia parthenogenetica demonstrated more regular groupings based on temperature and salinity respectively. Based on the discriminant analysis the width of uterus, maximum distance between two compound eyes, length of telson, total body length, distance of 3rd segment to end of abdomen, width of head, length of left antenna, length of right antenna, width of 3rd abdominal segment, maximum diameter of left eye, number of setae on left furca, number of setae on right furca, maximum diameter of right eye, length of furca and length of abdomen respectively showed increasing effect on separating the two population.

In this study, Otolithes rubber fillets were treated by sea cucumber Holothuria leucospilota extraction and then they were vacuum packed. Packed fillets were refrigerated at 4 centigrade for sixteen days. As an evaluation, microbial tests every four days including counting total bacteria, Pseudomonas, Enterobacteriaceae and hydrogen sulfide-producing bacteria were done. The results declared that during the period, the sum of the total bacteria in all treatments has increased and the maximum value of this index was maintained at 12th day in all treatments. Furthermore during the storage period, the number of bacteria which produce hydrogen sulfide and Pseudomonas and Enterobacteriaceae, were significantly greater than samples which were treated by sea cucumber Holothuria leucospilota extraction. Interestingly, there were no bacteria in the samples that were treated by sea cucumber Holothuria leucospilota 2% extraction for first four days. Also Enterobacteriaceae weren’t found in 1% and 2% extraction treatments until the 8th day of storage and the bacteria producing hydrogen sulfide weren’t seen in 2%, 1% and 0.5% extraction treatment until 12th, 8th and 4th day respectively. Results indicate dramatically that sea cucumber extraction has a considerable impact on samples including maintaining quality and increasing storage time of fish fillets in cold conditions. Notably 2% extract was more effective than other extracts concentrations in increasing survival of fillets.

This study was designed to determine the cultivation potentials and protein value of giant gourami as a new edible species and compare it with common carp as a common species. In order to analysis the growth phase of the giant gourami in a monoculture system and compare it with common carp, fishes were purchased in the same weight range (5±0.27 and 5.02±0.17 g, respectively) and presented to concrete pools in the same conditions, two treatments with 3 replicates. Fish were fed with common carp commercial diet of for one year. Growth performance such as survival rate, weight gain, SGR, FCR and price index showed more optimal results (P<0.05) in common carp, but the protein efficiency and visceral index in giant gourami improved, significantly (P<0.05). Fillet and carcass yields were significantly higher in giant gourami (P<0.05). The essential amino acids such as arginine, histidine, lysine, threonine and tryptophan, and non-essential amino acids including alanine and serine were remarkably higher in giant gourami compared to common carp (P<0.05). Also, there was no significant difference in EAA/NEAA at two groups of fish (P>0.05). Overall, the results of this study showed that common carp in the same condition in concrete pools was more able to grow than giant gourami, but better values for carcass yield and visceral index were obtained in giant gourami. In addition, according to the significant upgrading of the essential amino acids such as arginine, histidine, lysine, threonine and tryptophan and unnecessary amino acids including alanine and serine, and also the absence of significant differences in the EAA/NEAA at two species, due to the qualitative features and nutritional value of giant gourami, it can be considered as a valuable farmed fish.

The aim of this study was to investigate that the effect of commercial product of Multi-Behsil probiotic, including a mixture of several species of probiotic lactobacilli, bacilli, yeast and other probiotic microorganisms on growth and feeding performance in Oncorhynchus mykiss juveniles through the supplementation of diets. For this purpose, number of 600 fish juveniles with average mean weight 19.08±0.65 g were randomly introduced into 12 netting cages (size of 0.6´0.6´1 m with density of 50 fish per cage and placed in raceway concrete ponds). This experiment was conducted in a completely randomized design with a control group and three experimental treatments, M1, M2 and M3. In experimental treatments fish were fed with supplemented diets in levels of 200, 300 and 400 mg/kg of Multi-Behsil probiotic in diet for 45 days respectively. At the end of the trial, final weight and length, Average daily Growth, and Feed Conversion Efficiency showed significant differences in comparison with the control (P<0.05). There was no significant difference on specific growth rate, Thermal Growth Coefficient and Energy retention efficiency in comparison with the control group (P>0.05). While the crude protein (19.71%) and crude lipid (7.44%) of carcass in treatment of M3 had significantly increase (P<0.05) in comparison with the control group (crude protein 18.53% and crude lipid 7.17%). This study highlighted that the different levels of Multi-Behsil probiotic in rearing of Rainbow trout juveniles had different effects on growth and feeding performance in this fish.