Comparative study on the effect of dietary ß-carotene and phycocyanin extracted from Spirulina platensis on immune-oxidative stress biomarkers, genes expression and intestinal enzymes, serum biochemical in Nile tilapia, Oreochromis niloticus.

The current trial investigated the roles of ß-carotene and phycocyanin extracted from Spirulina platensis on growth, serum biochemical, digestive enzymes, antioxidant defense, immune responses, and immune gene expression in Nile tilapia (Oreochromis niloticus). Fish (1.52 ± 0.10 g) were randomly stocked to three treatments with three replicates (12 fish per replicate) in nine aquaria (60 L glass aquarium for each), and reared for 70-days. Three tested diets were formulated to be isonitrogenous and isolipidic, and were offered for experimental fish until ad-libitum three times daily at 09:00 a.m., 11.00 a.m. and 3:00 p.m. The first diet (control) was without supplementation. About 50 mg ß-carotene and 50 mg phycocyanin kg-1 were supplemented to the other experimental diets, respectively. Results indicated that feed intake was not (P > 0.05) differ among experimental diets. Compared to control diet wight gain and specific growth rate were significantly (P < 0.05) in fish fed diet containing ß-carotene, while, the highest weight gain and the best FCR were detected in phycocyanin diet. Survival fish among treatments was significantly (P < 0.05) differ and the highest survival rate was showed in fish fed diet supplemented with phycocyanin. Either ß-carotene or phycocyanin significantly (P < 0.05) improved the intestinal digestive enzymes compared with control diet, where the highest values of chymotrypsin, trypsin, lipase and amylase were noticed in fish fed phycocyanin. Diets supplemented with ß-carotene and phycocyanin significantly (P < 0.05) improved hematology parameters contents compared with to the control diet, and the best contents were detected in fish fed diet supplemented with phycocyanin. The highest significant (P < 0.05) phagocytic, lysozyme, immunoglobulin M (IgM), superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and total antioxidant capacity (T-AOC) activities were recorded in diet supplemented with phycocyanin. The transcripts of interferon gamma and interleukin 1ß genes were (P < 0.05) up-regulated in the liver of fish fed diet supplemented with ß-carotene and phycocyanin, but expression of HSP70 gene down-regulated in fish fed ß-carotene and phycocyanin containing diet compared control. The highest gene expression of the interferon gamma and interleukin 1ß was observed in fish fed phycocyanin.

Biological Characterization of Water in Damietta Branch of the Nile River, Egypt.

BACKGROUND AND OBJECTIVE: Damietta branch is one of the two main branches of the Nile River (Egypt), that often inhabited by many aquatic organisms, which affect and reflect its water characteristics. This study examine the relation between submerged macrophytes, their epiphytic microalgae and bacterial communities as well as the variations in their distribution and species composition with respect to season and location. MATERIALS AND METHODS: Macrophytes, epiphytes and water samples were collected from 5 sites distributed along Damietta branch. Macrophytes, epiphytes and bacterial indicators of pollution were identified using standard methods. RESULTS: Three submerged macrophytes (Myriophyllum spicatum, Ceratophyllum demersum L. and Potamogeton crispus) and 191 epiphytic algal taxa dominated by 87 Bacillariophyta and 62 Chlorophyta were recorded with significance seasonal and spatial variations. Myriophyllum spicatum was the most frequent macrophyte (p = 100%) and represent about 100, 100, 97.4 and 64.9% kg DW m-2 of the total collected macrophytes biomass during autumn, winter, spring and summer respectively. The relation between some epiphytic algal species and specific macrophytes was evident and the high organic pollution tolerant algal species like, Melosira granulata, Nitzschia palea, Synedra ulna, Oscillatoria limosa, Microcystis aeruginosa were recorded. Results of bacteriological analysis revealed a significance difference in total viable bacterial counts developed on either 22 or 37°C, total coliform, fecal coliform, fecal streptococci and Escherichia coli attributed to the seasons and sites. CONCLUSION: The results indicated different relations between macrophytes, epiphytes and bacteria, which is a useful biological tool for characterization of water quality in Damietta branch for different purposes.