Journal of Coastal Life Medicine

288-292

Authors: Md. Abdus Samad, Md. Nahiduzzaman, Md. Ashrafuzzaman, Md. Abdur Rashid, Mastarin Akter

Objective: To determine the impacts of three different low cost diets in monoculture system on the growth and production of indigenous catfish Shingi, Heteropneustes fossilis (Bloch, 1794) (H. fossilis) in earthen ponds. Methods: The experiment was carried out for a period of six months with three treatment groups (T1, T2 and T3) each having three replicates in the research ponds of Department of Fisheries, University of Rajshahi. Protein levels of formulated feed used in three treatments were 31% in T 1, 29% in T2 and 27% in T3, respectively. Stocking density of H. fossilis was 250 individuals/decimal in each treatment. At stocking, all fingerlings were of mean length and weight of (4.30 ± 0.01) cm and (4.20 ± 0.02) g, respectively. Fish growth and water quality parameters of the experiment were measured fortnightly. Results: The mean values of water temperature, transparency, pH, dissolved oxygen, free CO2, alkalinity and NH3-N of water varied from (22.08 ± 1.78) to (22.35 ± 1.76) °C, (27.09 ± 0.92) to (28.01 ± 0.82) cm, 7.44 ± 0.06 to 7.52 ± 0.06, (4.47 ± 0.10) to (4.53 ± 0.08) mg/L, (6.31 ± 0.33) to (7.05 ± 0.17) mg/L, (105.72 ± 2.97) to (109.11 ± 4.57) mg/L and (0.010 8 ± 0.002 0) to (0.011 2 ± 0.001 0) mg/L, respectively. Mean values of the water quality parameters showed no significant differences (P > 0.05) among the treatments. The net weight gain and survival rate were found to be (43.90 ± 0.42) g and (83.21 ± 1.43)% in T1, (37.50 ± 0.67) g and (79.28 ± 1.36)% in T2 and (34.30 ± 0.62) g and (78.95 ± 2.53)% in T3, respectively, which were significantly (P < 0.05) different among the treatments. The minimum value [(1.10 ± 0.22)%] of specific growth rate (SGR) was recorded in T3; whereas the maximum value [(1.35 ± 0.25)%] was recorded in T 1. The values of feed conversion ratio (FCR) of H. fossilis were found to be 2.68 ± 0.34, 2.31 ± 0.12, 2.22 ± 0.05 in T1, T2 and T3, respectively. Significantly higher weight gain, SGR and survival rate of H. fossilis were found in T1. The net production (kg/ha) was also found significantly (P < 0.05) different among the treatments. Net production in T1 (2 249.98 ± 10.66) was significantly higher than that in T2 (1 829.34 ± 4.50) and T3 (1 652.05 ± 16.69). Cost-benefit ratio (CBR) in treatment T1 in the present study was higher (1:1.91) than that in the other two treatments. Conclusions: The overall production of H. fossilis and CBR in T1 were significantly higher. From the study, considering water quality, production and economics, it is proved that the higher growth and survival rate of H. fossilis was found with 31% protein level of the feed in earthen ponds of Bangladesh.

299-308

Authors: Amira Rekik, Habib Ayadi, Jannet Elloumi

Objective: To compare the spatial and seasonal distribution of dinoflagellates in relation to environmental factors in north (restored) and south (not yet restored) coasts of Sfax. Methods: The present study was conducted during the year of 2010 and 2011 at 12 stations for evaluation of the spatial and seasonal distribution of dinoflagellates and abiotic parameters. Results: Results revealed a striking difference between the two coasts regarding pH with strong acidification of seawater in the south, which may be caused by industrial activity. Suspended matter was more in the north than in the south, which may be reasonably attributed to the recently added soil that has not yet fully stabilised. Inverted microscopy analysis of dinoflagellates showed 35 and 28 taxa in the north and south coasts of Sfax, respectively. Dinoflagellates developed in association with an important proliferation of common species like Gymnodinium sp., Prorocentrum lima and Prorocentrum micans. Two distinct associations of dinoflagellates species were identified: a north association involving an important abundance of Peridinium sp. and Protoperidinium sp., and a south assemblage concerning mainly Prorocentum triestinum. Chlorophyll a concentrations on the north [(2.48 ± 2.12) mg/L] and south [(4.95 ± 6.60) mg/L] coasts of Sfax were not correlated with dinoflagellates abundance, probably explained by the fact that an important number of dinoflagellates species are deprived of chloroplasts. The highest heterotrophic dinoflagellates mean abundance was recorded in south Sfax coast (1.64 × 102 cells/L) during summer. Conclusions: This study shows that environmental variables were in relation with the dinoflagellates community composition which exhibited clear variations over the study area.

317-320

Authors: Malek Besbes Hlila, Kaouther Majouli, Hichem Ben Jannet, Maha Mastouri, Mahjoub Aouni, Boulbaba Selmi

Objective: To evaluate the antioxidant and α-glucosidase inhibitory activities of luteolin and luteolin 7-O-glucoside isolated from Scabiosa arenaria Forssk. Methods: Antioxidant activity was measured by the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay. The α-glucosidase inhibition was determined by colorimetric assay using the enzyme from Aspergillus niger, and the p-nitrophenyl glucopyranoside (pNPG) as substrate. Results: The two compounds showed remarkable inhibition of α-glucosidase (IC50 = 0.009 2 mg/mL and 0.014 mg/mL, respectively) and they appeared to be even more potent than acarbose. A kinetic binding study indicated that the two compounds used a mechanism of noncompetition to inhibit α-glucosidase. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay further showed that the aglycone form (luteolin) possessed the best antioxidant activity. Conclusions: The results showed that the two flavonoids had biological activities with high potential for food and pharmacological uses.