Effect of dietary chitosan on growth performance, hematological parameters, intestinal histology and stress resistance of Caspian kutum (Rutilus frisii kutum Kamenskii, 1901) fingerlings.

This study was conducted to investigate the effects of dietary chitosan on growth performance, hematological parameters, intestinal histology, stress resistance and body composition in the Caspian kutum (Rutilus frisii kutum, Kamenskii, 1901) fingerlings. Fish (1.7 ± 0.15 g) were fed diets containing chitosan at different levels (0, 0.25, 0.5, 1 and 2 g kg(-1) diet) for a period of 60 days. Results showed that the feed conversion ratio significantly decreased in fish fed diet containing 1 g kg(-1) of chitosan compared to the other groups (P < 0.05), but there were no significant differences between treatments in terms of specific growth rate and condition factor (P > 0.05). Leukocyte increased in fish fed diet containing 2 g kg(-1) of chitosan compared to the other groups (P < 0.05). Lymphocytes, eosinophils and neutrophils did not significantly change among dietary treatments (P > 0.05). Also, the chitosan supplementation did not affect the whole-fish body composition (P > 0.05). Light microscopy demonstrated that the intestinal villus length increased in fish fed diet containing 1 g kg(-1) of chitosan compared to control group (P < 0.05). While 11 and 13 ‰ salinity and 30 °C thermal stress had no effect, 1 g kg(-1) of chitosan (P < 0.05) showed highest survival rate (70 %) in 34 °C thermal stress. The results showed that chitosan in the diet of the Caspian kutum fingerlings could improve feed conversion ratio, the nonspecific defense mechanisms and resistance to some of the environmental stresses.

Study the seasonal steroid hormones of common carp in Caspian Sea, Iran.

In this investigation, serum steroid hormones such as testosterone (T), 17ß-estradiol (E2) and progesterone (P) in 12 female of the migratory population of Common carp (Cyprinus carpio) in southeast of Caspian Sea during a year from May 2011 to May 2012 were studied. The results of present study revealed that changes in levels of steroid hormones, (E2) and (T) were closely correlated to ovarian development. There was significant difference in level of 17 ß- estradiol between autumn and winter seasons that the highest of 17-ß estradiol level was observed in autumn season. In the case of progesterone hormone, higher levels was recorded in summer season and there was significant difference between summer and spring seasons and lower level of testosterone was observed in spring season.

Effect of copper sulfate on the survival and growth performance of Caspian Sea kutum, Rutilus frisii kutum.

The aim of present study was to determine the LC50/96 h value of copper sulfate and determine the growth performance of Caspian Sea kutum) Rutilus frisii kutum (fingerlings during 60-days sub-lethal copper (Cu). After acclimation period to two weeks, for determine the LC50/96 h value, total of 27 aquarium with a capacity of 60 L each stocked with 10 fishes an aquarium. Tunney four aquarium and 8 concentrations of (Cu) composed the 24 treatments while 3 other aquaria were used as control. For each treatment, three replications were conducted. And experiment to determine the growth performance fish were transferred into fiberglass aquaria of 200 L water capacity for growth trials. The treated fish were kept in the aquarium containing sub-lethal concentrations of Cu (0.11 and 0.23 mg L(-1)) and affected to grow for 60 days, while control fish were placed in metal free water. The results indicated that median lethal concentrations (LC50) of copper to Caspian Sea kutum for 96 h exposure was 2.310 ppm. The chronic sub-lethal water-borne Cu exposure to the fish exerted that fish had significantly decreased final body weight in comparison to control group. The copper sulfate also had significant negative effects on specific growth rate (SGR) and feed conversion efficiency (FCE) in comparison to those fed the control group. The feed conversion ratio (FCR) and condition factor (CF) were significantly increased in comparison with the control group (P < 0.05). Also survival rate in experimental treatments in comparison with control group, was significantly decreased (P < 0.05). The treated fish exhibited significantly lower body weight and length gains than that of control. The increments of fish weights, fork and total lengths, condition factor, feed intake and condition factor of treated and control fish varied significantly during study period. Hence, concluded that copper sulfate is toxic for Caspian sea kutum (Rutilus frisii kutum).

Effects of acidic water in combination with aluminum on swimming behavior and survival of yolk-sac larval in Goldfish (Carassius auratus gibelio).

Yolk-sac fry of Goldfish (Carassius auratus gibelio) were exposed to various concentrations of Al and pH for 3, 7 and 10 days. In this study number of dead fish, total length of larvae, yolk sac length, swimming activity, the number of gill cover movements and the number of heart beat was measured. The lowest and highest number of gill cover movements belong to the waters containing 50 mg L-1 of aluminum, pH 5.25 and acidic waters with pH 6.7 respectively. There was no significant difference in the number of heartbeat between control group and larvae exposure to acidic waters with pH 6.7 and waters containing 150 mgL-1 of aluminum and the highest number of heartbeat belong to these larvae than other experiment doses. The larval of Goldfish in the all experiment doses lost their swimming ability after 3 days. The highest number of swimming larvae and also lowest number of non-swimming larvae significantly belong to control group compared to other experiment doses (p < 0.05). The larval in the control group only were maintained their swimming activity after 7 and 10 days and in the all experiment treatments lost their swimming ability. There was significant difference in the number of dead larvae and the number of non-swimming larvae between control group and larvae exposure to acidic waters and waters containing 300 mgL-1 of aluminum and pH 4.75 (p < 0.05) and lowest number of non-swimming larvae was observed in the control group. Also the highest of yolk sac length belong to the waters containing 600 mgL-1 of aluminum and pH 4.75. The larvae of Goldfish were not survived in the waters containing 300 and 600 mgL-1 of aluminum and waters with low acidity after 7 days.

Allozyme variability in populations of trout (Salmo trutta) from the rivers of Russia and Iran.

For the first time, an analysis was carried out of allozyme variability in trout (Salmo trutta) from three rivers of Iran. We studied 23 gene loci coding enzymes: glycerol-3-phosphate dehydrogenase (G3PDH), aspartate aminotransferase (AAT), malate dehydrogenase (MDH), lactate dehydrogenase (LDH), creatine kinase (CK), malic enzyme [NADP-dependent MDH] (MEP), superoxide dismutase (SOD), esterase (EST), and esterase D (EST-D). The obtained data demonstrate the similarity between the trout samples from different rivers of Iran according to genetic characteristics. Taking into account the differences by allozyme markers of allele frequencies and allele composition of some loci, we should expect that Iranian trout diverges significantly in genetics from the other trout populations of the Caspian Sea.