JOURNAL OF AQUATIC ANIMALS & FISHERIES
Year:2012 | Volume:3 | Issue:9|Papers Count:8

The effects of salinity stress on survival rates of larvae of Litopenaeus vannamei shrimp was tested for Six nutritional treatments each with three replicates were fed to shrimp larvae (average weight, 0.0013 g) including control treatment which was Artemia nauplii unenriched and second to sixth which were Artemia nauplii enriched with 200, 400, 600, 800 and 1000mg garlic extract per kg feed, respectively. The One way ANOVA results showed that all treatments had differences significantly in terms of survival rates of larvae compare to control group (P<0.05) and among shrimp groups, whose were fed Artemia enriched with 200mg garlic extract per kg feed had the best growth, survival rates and length (0.0062 mg, 81.6% and10.6mm) compared to others.Treatment 3 (with concentration of 400mg garlic extract per kg of feed) and control group after the second treatment, performed better growth and survival rates in shrimp larvae than the other treatments but the lowest survival rate evaluated in shrimps fed Artemia nauplii enriched with 600T 800 and 1000 mg garlic extract per kg feed, orderly. Regarding to specific growth rate (SGR) treatments 2and 3were higher compared to other treatments significantly (P<0.05).

This study has been conducted to determine the effect of Postlarva of Litopenaeus vannamei stocking density on growth and survival index and was carried out in 9 ponds (one hectar) from April to August 2011 in a field belonging to 647 Ata corporation in Gowater Site in Chabahar. After pond prepartion, postlarvaes at PL15 in three different densities of 15, 20 and 25 square meter (labeld treatment 1, 2, 3 respectivly) with three replicates for each one have been stored. Physical and chemical factors of water such as tempreture, oxygen, pH twice daily (morning and evening) and also salinity and transparency have been measured once a day. Feeding of postlarva during culture period based on requirements in different age and weight, levels and in different environmental conditions was performed using Internal food concentrates. biometric practices of shrimps by way of cast net and feeding trays once every ten days have been calculated and recorded. Culture management practices were similar for all ponds. The results of the effect of density in 115 days rearing on growth indices between treatments 1 and 2 and 3 of the final product and the mean weight, showed significant differences in all three treatments at 95% confidence level (P<%5), Also in terms of survival rate treatments 1 and 2 showed significant diffrences in comparison with treatment 3 (P<%5). The overall Results of mean weight at 115 days growing in treatment 1 and 135 days growing in treatments 2 and 3, respectively, 17.93±.23 and 16.68±.07 and 15.64±.12 g and the final production order of, 2460±78.1, 3033 ± 76.38, 3200±50 kg and average daily growth were .18±.002, .14±.002, .13±.001 g per day, respectively. Also the highest survival rate and the lowest feed conversion ratio that were 91.44±1.72 and 1.3±.06 which belonged to treatment 1 and the lowest survival rate and highest feed conversion ratio were respectively 81.86±.78 and 1.57±.03 which belonged to treatment 3 is obtained. The results of economic surreys at different densities showed that the highest mean weight of treatment 1 and the lowest feed conversion, were economically better than other treatments. Also with Increasing the stocking density, economic profit decreased.

Results show that this species (122 specimens) has the average total length of 171.2 ±31.6 mm, average total weight of 62.9±19.7 g, and average age of 3.49±0.9 year. Average number of scales on the lateral line is 50.83±1.8, soft rays of dorsal fin were 7.96±0.2, and anal fin rays were 17.58±1.0.The average head length was 24.47±1.9%, eye diameter was 6.1±0.4%, the maximum body height was 26.17±1.4%, height and length of dorsal fin were 20.22±1.5 and 10.96±0.8% respectively, height and length of anal fin were 12.66±0.8% and 18.17±1.5% respectively. The distance between the pectoral and ventral fins was 24.18±1.7% and the distance between the ventral and anal fins was 20±1.5%. The pre-dorsal length was 52.21±1.7% of the standard length. The brood stocks and fingerlings were different in one meristic characteristic and 9 morphometric parameters. Female and male Brood stocks were different in 12 morphometric characteristics, especially in body height, dorsal and anal fin lengths. Also from the appearance of fish point of view the matured males had epithelial turbecles on the head and body, the body color is relatively darker than females. Also the color of ventral and anal fins was more light-red than females.

In this study, Saline solutions containing cations (Na+, K+, Ca+2, Mg+2) were used to investigate the effect of ions on motility characteristics of spermatozoa (sperm movement duration and percentage of motile spermatozoa) and fertilizing capacity of sperm (fertilization rate, hatching rate, larvae length during hatching, larvae length during active feeding and survival rate) in Aristichthys nobilis. To test the effects of ions on sperm motility, Na+ (NaCl) (1495, 1886 and 2277 mg/L), K+ (KCl) (819, 936 and 1503 mg/L), Mg2+ (MgCl2) (48, 72 and 96 mg/L) and Ca2+ (CaCl2) (20, 50 and 70 mg/L) were used. The results showed highest sperm movement duration in solutions containing 1503 mg/L KCL, 50 mg/L CaCl2, 2277 mg/L NaCl and 48 mg/L MgCl2 respectively. Among tested ions, solutions containing NaCl had more influence on fertilizing capacity of spermatozoa than other ions. Our results showed that solutions containing CaCl2 had a negative effect on fertilizing capacity of spermatozoa. Understanding the effects of these ions could be useful to the aquaculture industry and subsequently to improving the quality of fish sperm during artificial propagation.

A comparative study was conducted on concentration of heavy metalsHg, Cd, Pbin the muscle and shell of Fenneropenaeus indicus in marine, 2011. Three kilogaram were collected shrimp of marine too weight 13.18±0.78 g. Metals were extracted from the tissues using wet digestion method and concentration of the heavy metals were measured by Atomic Absorption Spectrophotometer Perkin Elmer 4100 from Kimia Pajohe Alborz labratory (Shahrekord). Concentration of heavy metals in muscle were lower than in shell of shrimp. Concentration of heavy metals in the muscle and shell of Fenneropenaeus indicus were measured Pb>Cd>Hg. In this study concentration of Hg, Cd, Pbin the muscle and shell of Indian shrimpsignificant difference (P<0.05). Mean of Hg in muscle and shell were measured 0.034±0.002 and 0.045±0.003 mgKg-1 and concentration of Cd in muscle and shell were 0.101±0.005 and 0.120±0.007 mgKg-1, respectively. Also concentration of Pb in muscle and shell were measured 0.133±0.005 and 0.164±0.004 mgKg-1. Concentrations of Cd in muscle were higher thancomparison of WHO standards. Concentrations of Hg and Pb were higher thancomparison of WHO and FDA and were lower thancomparison of UKMAFF and NHMRC.

This Study was done in order to evaluate the effect of dietary prebiotic yeast cell wall (Saccharomyces cerevisiae) so called (YCW) on growth indices of Acipenser nudiventris fingerlings. 240 cultural ship fingerlings weighted average number (±SD) 7.61±0.01 g for 8 weeks were fed by four different diets including 0, 0.5, 1 and 1.5% YCW in basal diet in form of 4 treatments (following control, 1, 2 and 3). The treatments in twelve 500L fiberglass tank with density of 20 fish in each tank, in the form of 4 treatments with 3 replicates were randomly distributed. The results showed that growth indices such as final weight, specific growth rate, average daily growth, feed convertion ratio in all treatments had no statisical significant differences in compared with the control (P>0.05). Hepatosomatic index in treatments fed by YCW was significantly higher than control (P 0.05). Condition factor only in treatment 2 was significantly higher than control. Survival rate in all treatments was significantly higher than control. The experiment indicated that YCW didn t influence ongrowth indices highly in Acipenser nudiventris.

In this study, effect of astaxanthin on growth, pigmentation and blood factors were studied in rainbow trout weighted average (93±0.64g) in pools of Mr. Sarshar farm that was located in the 3000 Road of Tonekabone region of Mazandaran province for 8 weeks. Two treatments and three replicates were employed as follows: Treatment A: fed with commercial diet (control), treatment B: 41mg/kg astaxanthin. All treatments were fed in hours 8, 12, 16 respectively. It should be considered that the feeding rate of biomass weight were examined after each took biometrics. Finally, blood samples were taken from the caudal vein of the fish. The results revealed a significant difference between treatments in terms of weight and length (p<0.05) and no significant difference in food intake and growth performance parameters, including FCR, SGR, GR, BWI% and survival rate between treatments (p>0.05). In terms of pigmentation between experimental treatments, astaxanthin was created more change color than control group that using of SalmoFanTM, the degree color of meat in the end of period reach to 28o. Results of blood factors showed that between WBC, RBC, Hb, HCT, Lymphocytes, Neutrophils, Monocytes and IgM were significant differences between treatments (p<0.05). So we can conclude that 41mg/kg astaxanthin dietary, due to economy, would be proper diet in feeding of rainbow trout propagation.

This research was carried out in the August of 2011 in Shahid Maleki Warm Water Fish Culture Centre in Ahwaz, and that aim was to evaluation of optimum level Nacl bath for disinfection in figerlings of bighead carp (4.38±0.59 g) common carp (5.43±0.87 g) and grass carp (5.28±0.65 g) during transport. After 1h response to different salinity (1>, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 ppt) we observed that salinity up to and include 18 ppt do not produce significant abnormal behavior and mortality in trial fishes. But salinities above of 20 ppt produced adverse effects on survival and behavior and normal appearance. These results demonstrate that using up to short-term (1h) Nacl bath (18ppt) to reduce the incidence of diseases, mortality and transportation could be suggested in our trial condition.