فصلنامه فیزیولوژی و بیوتکنولوژی آبزیان
سال هشتم شماره 3 (پاییز 1399)

The genus of Bacillus, due to its higher resistance to harsh environmental conditions, is the most broadly used probiotic in aquaculture. Present study was designed to investigate the effects of Bacillus cereus on growth, digestive enzyme activity and serum biochemical and immunological indices in common carp (Cyprinus carpio). After the 14-day adaptation, fish with mean weight of 70.57±0.72g were allocated into 12 tanks (15 fish per tank) and fed basal diet (control group) and diets containing probiotic B. cereus in three doses, including 107, 108, and 109 CFU.g-1. After 45 days feeding, diet supplemented with higher dose of probiotic showed significantly better result of weight gain, digestive enzyme activities for trypsin, amylase and lipase, mean white blood cell and lymphocyte counts, total antibody level, lysozyme and protease activities than those with the control diet (p < 0.05). Meanwhile, albumin, triglyceride and aspartate aminotransferase levels were remarkably higher in medium and high doses than the control group (p < 0.05). Based on the present results, supplementation of probiotic B. cereus, especially at 109 CFU.g-1, is recommended to enhance the growth performance, hemato-immunological responses, and digestive enzyme activities in common carp.

The effects of Iron (Fe+2), copper (Cu+2) and zinc (Zn+2) trace elements on lipid and fatty acids of microalgae Spirulina platensis were investigated under laboratory conditions. The specimen cultured in Zarrouk media with 4 groups including control and 3 different concentrations of iron, zinc and copper trace elements with the volume of 10 times compare to control. Maximum and minimum of lipid contents were measured in iron and zinc treatments with 5.28 and 1.47% dry weight, respectively. The major group of fatty acids were C16:00, C18:00, C16:1n7, C18:1n9, C18:2n6 and C18:3n3. Maximum and minimum saturated fatty acids (SFA) were measured in iron and zinc treatments with 43.50 and 37.54 mg.g-1.dw-1, respectively. The highest value of mono and poly unsaturated fatty acids (MUFA and PUFA) were determined in zinc and iron treatments (53.19 and 39/51 mg g-1 dw-1), respectively, compared with other treatments. In conclusion, zinc treatment increased the contents of EPA, DHA, MUFA and omega 6 as compared to other treatments and the highest amount of PUFA was obtained in iron treatment.

The genetic diversity of Caspian lamprey, (Caspiomyzon wagneri) was studied using  the microsatellite technique in Shiroud River. 67 caudal and dorsal fin samples were collected from spawned Caspiomyzon wagneri caught from Shiroud River in autumn 2015 and spring 2016 seasons. Genomic DNA was extracted using ammonium acetate method and polymerase chain reactions (PCR) were conducted using 10 paired microsatellite primers. The quantity and quality of DNA were assessed using spectrophotometry and a horizontal electrophoresis in 1% agarose gel methods and were stained using silver nitrate method. The results showed that it was produced six polymorphic and four monomorphic loci. The average real and effective number of alleles in autumn migrant were 2.66 and 1.88 and 3.16 and 2.06 in spring migrant. The mean observed and expected heterozygosity in autumn migrant were calculated 0.239±0.101 and 0.363±0.116 and 0.374±0/110 and 0/434±0/093 in spring migrant, respectively. More loci were out of Hardy-Weinberg equilibrium (p < 0.05). Based on the analysis of molecular variance, Fst and Rst were 0.153 and 0.200 that showed significant differences (p < 0.01). This study gave evidence of the presence of two separated populations in studied river that should be considered in restructuring reserves.

The genetic diversity and population structure of cultured male and female herds of beluga sturgeon (Huso huso) brood stocks were estimated in International Sturgeon Research Institute using four DNA microsatellite loci. All loci were in polymorphic pattern. The number of alleles and observed heterozygosity ranged between 6-37 (mean 18) and 0-0.87 (mean 0.41), respectively. Allelic richness (Na) was acceptable and genetic variation was in moderate decreasing pattern.  For survey of genetic differentiation in individuals, the Fst was estimated at 0.045, indicating a low genetic differentiation among breeders. Samples from male herds in Spl-104 and Ls-19 loci were at Hardy-Weinberg equation and other loci showed a pattern of deviation from equilibrium, which could be as a result of reduced population size and the presence of an inbreeding phenomenon. According to the results obtained from molecular variance analysis, the genetic difference between two populations was 3%. The results of the study indicate that genetic diversity was low in the cultured beluga brood stocks, resulting in the reduction of wild beluga breeders in the southern basin of the Caspian Sea.

Swan mussel, Anodonta cygnea, is a freshwater bivalve inhabitant of Anzali wetland, which population is in danger due to pollution and habitat destruction by human manipulation. In the present study, some reproductive traits of this species were evaluated for one year period using microscopic and biometric studies. The mean length was 10.6±0.1cm, the mean width was 6±0.04cm, the mean height was 4±0.04cm, the mean weight was 132±3g and the mean age was 6±0.1 years old. In all shells, two sexes were separated. There was no external feature for sex determination. The frequency of female was 1.5 times that of male. The mean diameter of mature oocyte and sperm were 139.95±8.1 and 4.5±0.26μm, respectively, and the mean area of ​​them was 15255.58±1834.4 and 9.1±1.16μm2, respectively. The mean fecundity was 107844.6±20621.9. Both of male and female gonads were in developing phase in spring (May and June) and in summer (July and August). The spawning stage occurred in the fall and the post-spawning stage in the winter. The development of glochidia were completed in January and the release of them from the gill were occurred between January and March.

In this study, the occurrence of mycosporin-like amino acids in the sea urchin Echinometra mathaei from Persian Gulf was assessed for the first time. Mycosporine-like amino acids (MAAs) are UV-absorbing compounds that are synthesized by some organisms to counteract the harmful effects of UV radiation. Mycosporine-like amino acids in different parts of E. mathaei was assessed by HPLC and LC-MS analysis. Moreover, antioxidant ability of total extract of shell as well as its fractions were evaluate using DPPH assay. Combination of UV and LC-MS data values revealed the occurrence of Shinorine in the shell of E. mathaei. Total extract of urchin shell showed IC50 value of 231µg/mL which contributed to the mycosporine-like amino acid shinorine.

Alosa braschnikowi has the most abundant in the Southern Caspian and is considered as economic and valuable species. Hematological features of fish are one of the most valuable evidence of physiological stages in fish. For evaluating the effects of ages, sexes and reproductive stages on hematological, immunological and hormonal factors of Alosa braschnikowi, 37 specimens were randomly captured from the beach of Roudsar in February, March, April, May and November 2018. After fishing, blood samples were taken from fish and fish were compared based on sex, age groups (3, 4 and 5 years old) and reproductive stages (pre-spawning, during spawning and post-spawning) after measuring hematological, immunlogical and hormonal parameters. The result showed that there was no significant difference in hematological, immunological and hormonal factors between males and females (P>0.05) and only, eosinophils and testosterone had significant difference (p < 0.05). Comparison of different ages also showed that red blood cells, hemoglobin, hematocrit, cortisol and MCHC experienced significant difference (p < 0.05) and other factors didn’t have any difference (P>0.05). Also, in comparison with different reproductive stages, most factors had significant difference. Generally, hematological, immunological and hormonal factors of this fish were not affected by sex and were only partially influenced by age. However, reproductive stages often had a significant impact on these factors.

Marine echinoderms, including sea urchins, have a high ability to survive due to living in shallow environments that are suitable for the growth of microbes. Due to such unique characteristics, much attention has been paid to the purification and identification of a variety of bioactive compounds, especially antimicrobial peptides. Therefore, the present study aimed to investigate the coelomic fluid of the burrowing urchin (Echinometra mathaei), as the most abundant species in the Persian Gulf, and to extract the aqueous and organic phases from coelomocyte cells by a particular solvent. The results of the agar disk and well diffusion assays showed that the organic phase had a higher antibacterial activity, which could be attributed to its protein content. The organic phase at a concentration of higher than 12.5mg.mL-1 caused complete inhibition of the bacterial biofilm, while it destroyed the biofilm completely in the concentration of 100mg.ml-1. The organic phase lacked haemolytic activity at the concentration of 100mg.ml-1 and even inhibited the red blood cell haemolysis. Based on the results, it is suggested that the organic phase extracted from the burrowing urchin coelomocyte may be considered for the extraction and identification of antimicrobial compounds.