Female Broodstock Reproductive Output, Larval Rearing And Spat Survival Of Black Lipped Oyster (Pinctada Margaritifera)

Overexploitation of Pinctada margaritifera as one of the natural resource was leading to a dramatic loss of its population in the north coast of Persian Gulf. Low abundance and density existing in the natural beds and poor larval recruitment prompted research on hatchery propagation of this species. Further research should be carried out to improve the survival and growth of larvae produced through artificial propagation. This study addressed important issues in relation to the supplementation of polyunsaturated fatty acids (PUFA) in diet and their role in egg quality and biochemical composition, and larval growth and survival; microalgae biochemical composition and its role in larvae culture; and spat settlement and transfer time to the sea farm. In the first experiment, the effects of supplementary PUFA on oogenesis and hatching rate of P. margaritifera broodstock were compared with naturally fed oysters and those fed only microalgae. Supplementary food was effective (P < 0.05) on producing larger sized eggs (57.6 μm) and larvae (80.1 μm), and higher percentage of P. margaritifera D shape larvae (31.3%). Palmitic (16:0) and stearic (18:0) acid were the major saturated fatty acids in neutral and polar parts of gonad lipid. Oysters fed with supplementary PUFA had more docosahexaenoic acid (DHA) and less monounsaturated fatty acids (MUFA) in their gonad. The ratio of n-3/n-6 fatty acids in neutral lipid was the best representative of differences in conditioning of oysters for spawning and interpretation of the results of egg size and hatching performance. In the second experiment, the effects of partial supplementation of the diet with PUFA on growth and survival of P. margaritifera D-shape and umbo larvae were investigated. PUFA supplemented in droplet form did not increase the growth and survival of D-shape and umbo P. margaritifera larvae compared to those fed fresh algae of T. Iso (P > 0.05). Considering results of size range of larvae, it can be concluded that through the grading process, a great number of larvae would be lost in treatments with supplementary diet compared to those fed with T. Iso only. D-shape and umbo larvae showed a similar performance in survival, with the highest related to larvae fed with fresh algae followed by 10, 30 and 100% of diet replaced with PUFA emulsions. While the lowest survival attributed to the unfed larvae

Anesthetizing Pinctada radiata with MS-222

The effect of MS 222 for inducing anesthesia in 60 P. radiata was studied under different concentration and various stimulating factors. Based on the results of mortality rate, induction time, duration of anesthesia, recovery time, responses of the organism to the anesthetic and handling, it was concluded that the concentration of 1ppt of MS-222 was the best for inducing anesthesia, in P. radiata

Production of tropical oyster seed in hatchery

Oysters have been collected from wild since long time ago for human consumption. Recent development in aquaculture has allows the production of its seed in hatchery. Factors favoring the oyster production are stocking density, water quality and the availability of live food. These factors can increase the growth and survival of the oyster. Fundamental knowledge on life cycle and biology of oyster is important as it can become the basis for successful development of oyster culture. Due to the limited seed supply, hatchery produce seedlings are important to support the development of oyster industry

Effects of location and time of Pinctada margaritifera spat transfer from hatchery, on its growth and mortality in the sea

This study reports on the effects of different locations and hatchery transfer time on the growth and mortality of P. margaritifera spat. In the first experiment spat of P. margaritifera were transferred to the sea farms in Hendurabi and Lavan Islands at 25, 50, and 65 days post settlement and a Control was kept in the hatchery. Retaining spat in the hatchery more than 25 days after settlement did not improve the growth and mortality of juveniles. Spat grown in Hendurabi were significantly greater in size compared to those grown in hatchery and Lavan at the end of experiment (P < 0.05). Growth curve both in hatchery and sea farms best conformed to cubic model. In the second experiment, 55 days old spat from two propagation trials at a size circa 0.5 mm were deployed to the Hendurabi on 5th September and 7th October 2008 and were reared for five months accordingly. Spat of first deployment were significantly greater in size than second deployment at the end of experiment (P < 0.05). Maximum (0.34 mm d− 1) and minimum (0.11 mm d− 1) daily growth rate (DGR) were observed in September and October 2008 respectively. Mean DGR in fall was more than double in winter. There was positive correlation between water temperature and DGR, whereas food abundance, as expressed by concentration of chlorophyll-a, had a negligible effect

Effects of dietary peppermint (Mentha piperita) essential oil on survival, growth, cannibalism and hepatopancreatic histopathology of Portunus pelagicus juveniles

A two-part experiment was performed to determine whether dietary peppermint oil could improve the growth and/or decrease aggression among blue swimmer crab, Portunus pelagicus early juveniles. A total of five isonitrogenous diets were made that contained increasing peppermint oil levels of 0.00, 0.05, 0.10, 0.50 or 1.00%. These diets were fed to 45 replicate crabs in each treatment (total of 225 crabs) for 12 days, the final sizes and weights were measured, and then placed in 3 replicate containers (30 in total/treatment) to allow the opportunity for cannibalism over 10 days. After 10 days, the remaining crabs were examined for any histopathological changes in gills or hepatopancreas. Results showed dietary peppermint oil, at the tested levels, had no effect on the growth or cannibalism, in either experiments (p > 0.05). However, there were substantial changes in the hepatopancreatic histopathology that included thinner tubules and significantly less B- and R-cells from 0.10% dietary peppermint oil and above. The unaffected growth or cannibalism indicate that the levels of dietary peppermint oil used were insufficient and further investigations are required, particularly on the implications to the hepatopancreatic changes

Apparent digestibility coefficients and nutritional value of Iranian cottonseed meal varieties for rainbow trout (Oncorhynchus mykiss)

Three different varieties of cottonseed meal (CSM) were evaluated to measure the apparent digestibility coefficient (ADC) of the nutrients using chromic oxide (Cr2O3) as an indigestible marker. Five experimental diets were prepared and mixed with 1% of Cr2O3, 2% of mineral and vitamin each of which were premixed. Diet 1 was used as the control diet. Diets 2, 3, 4 and 5 were formulated using 70% of the control diet together with 30% of each ofthe cottonseed meal Pak (CSMP), cottonseed meal Sahel (CSMS), cottonseed meal Akra (CSMA), and soya bean meal (SBM), respectively, in three replications.The ADC of the three CSM varieties was measured to be 53.8-62.7%, 60.2-66.6% and 75.6-82.4% for dry matter, fat and crude protein, respectively. Survival rate for all fishes used in this study was more than 98%. Fishes fed with the CSM diets were not significantly different compared with those fed with the SBM diet in terms of survival rate (p>0.05). Apparent protein digestibility of CSMP and CSMS showed no significant difference with SBM (p>0.05). Therefore, it could be concluded that two kinds of CSM could be used as a replacement for SBM in rainbow trout as a protein source

The effects of dietary supplements of polyunsaturated fatty acid on pearl oyster, Pinctada margaritifera L., gonad composition and reproductive output

Black-lip pearl oyster, Pinctada margaritifera broodstock was collected from the wild. Egg production, hatching rate and larval development were compared between oysters induced to spawn within 2 days after collection in the wild (T1), oysters fed a pure microalgae diet during 24 days before spawning (T2) and oysters fed the same microalgal diet in which 10% of the algae were replaced with 2 μm polyunsaturated fatty acid (PUFA)-rich microspheres (T3). Administration of lipid microspheres resulted in larger sized eggs, a higher percentage of D-larvae and larger sized 48-h-old larvae (P0.05). The gonads of oysters fed supplementary PUFA contained more docosahexaenoic acid (DHA) and less monounsaturated fatty acids. Higher level of DHA in gonads of T3 was associated with oogenesis and embryogenesis success. The n-3/n-6 ratio in the neutral lipid fraction provides a good indication of the spawning condition and predicting egg size and hatching rate

Seasonal variation of catalase and heavy metal enzyme (Pb, Cd, Ni) in Pinctada radiata in Persian Gulf, Iran

We have different possibilities and tools to assess the impact of pollution on marine ecosystems. The ecotoxicological approaches are based on the use of biomonitors and biomarkers. The purpose of our study was to evaluate the antioxidant enzyme catalase (CAT) as biomarkers in an edible species, Pinctada radiata (Mollusca, Bivalvia) associated with the environmental pollution(heavy metal, Cd, Pb, Ni) in the Persian gulf. Samples were collected seasonly from march 2012 till march 2013 at three station in the Persian gulf (Nakhilo, Hendorabi and lavan Islnad). Mollusc bivalves (Pinctada radiata) with the same shell length (40-50mm) were collected from the sampling sites, transferred to the laboratory and dissected the same day. The mantle was dissected and samples were prepared for biomarker analyses and measuring the heavy metal in soft tissue. The enzyme concentration were determined by using standard methods. Biochemical data showed a no significant The results concluded from the amount of heavy metals in the sediment and soft tissue of pearl oyster(pinctada radiata) show no significant correlation with the level of catalase enzyme. The present study strongly suggests that monitoring programs should compare sites with similar physicochemical characteristics when using a complementary biomarker approach

Refined oil production from Patin catfish (Pangasianodon hypophthalmus) by-products

In this study, oil was extracted from the liver and visceral fat of Patin (Pangasianodon hypophthalmus) and refined. The yield of oil after refining was 49.98%. The major yield loss (34.20%) happened during the degumming procedure. Fatty acids found in the crude and refined oil were C12:0, C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C18:4, C20:0, C20:1, C20:4, C20:5, and C22:6. The dominant saturated, monounsaturated and polyunsaturated fatty acids were C16:0, C18:1 n-9, and C18:2 n-6, respectively. The total amounts of monounsaturated fatty acids did not change significantly during refining procedure (p>0.05), whereas the total amount of saturated and polyunsaturated fatty acids changed significantly (p<0.05). The n-3 to n-6 ratios of crude, degummed, neutralized, bleached, and deodorized oils were 1.11, 1.06, 1.05, 1.02, and 1.01, respectively

Proximate and fatty acid composition of liver and fatty tissue of patin catfish (Pangasianodon hypophthalmus)

The visceral storage fat and liver of patin catfish (Pangasianodon hypophthalmus) are normally discarded, which incurs cost and can cause environmental pollution. However, these may be potential sources to extract fish oil. The proximate and fatty acid compositions of liver and fatty tissue of patin catfish were investigated to evaluate the suitability of these by-products for extracting fish oil. Fat was extracted using a low temperature solvent extraction method. The average fat content of fatty tissue and liver of females were 77.64 and 11.71%, respectively, whereas in males this was73.23 and 9.59%, respectively. Fatty acids found in the extracted oil of these byproducts were C12:0, C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C18:4, C20:0, C20:1, C20:4, C20:5, and C22:6.The major fatty acids presented in these tissues were palmitic (C16:0), oleic (C18:1n-9), and linoleic acid (C18:2 n-6). The total amount of polyunsaturated fatty acids of liver from male and female patin catfish were 13.31 and 13.30%, respectively, whereas in the fatty tissue these were11.64 and 12.09%, respectively. The n-3 to n-6 ratios of liver and fatty tissue of females were 1.61and 0.95, respectively, whereas in male fish these were 1.31 and 1.05, respectively. Results of this study indicated that the liver and fatty tissues of patin catfish are suitable sources of fish oil specifically due to the presence of monounsaturated and n-3 polyunsaturated fatty acids