Digestibilidade aparente de dietas práticas com diferentes relações energia:proteína em juvenis de pirarucu

The objective of this work was to determine the apparent digestibility of nutrients and energy of diets for pirarucu (Arapaima gigas) juveniles. Eight experimental diets containing four energy:protein ratios (11, 10.1, 9, 8 kcal digestible energy per gram of crude protein) and two non-protein energy sources (soybean oil and poultry fat) were tested in a 4x2 factorial scheme, in triplicates. Two hundred and forty pirarucu juveniles weighting 96.8±2.3 g were distributed in 24 cylindrical-conical fiberglass tanks, adapted for feces collection (modified Guelph system). Fish were fed twice a day to apparent satiation, with experimental diets containing 0.5% of chromium oxide as inert marker in order to determine the apparent digestibility coefficients. Diets containing an energy:protein ratio of 9 kcal digestible energy per gram of crude protein resulted in significantly lower apparent digestibility coefficient for dry matter, crude protein and non-nitrogenous extract. The highest apparent digestibility coefficients for crude fat was obtained with soybean oil. The dietary energy:protein ratio influences the nutrient and energy apparent digestibility coefficients to pirarucu juveniles

Proximate and fatty acid composition of three tuna species from Hadhramout coast of the Arabian Sea, Yemen

The Proximate and fatty acid composition were evaluated in three species of tuna; Yellowfin tuna (Thunnus albacares), longtail tuna (T. tonggol), little tuna (Euthynnus affinis) caught from Hadhramout coast of the Arabian Sea. The results of proximate composition showed high protein content in the flesh of all species, ranged from 22.52% to 24.36%. The average moisture, lipid and ash contents in the flesh of the three fish species were in the range of 70.13–74.0%, 2.34–4.66% and 1.25–1.37%, respectively. The fatty acid profile of all fish was dominated by saturated fatty acids, (31.76–36.77%), followed by polyunsaturated fatty acids (31.21–31.59%) and then monounsaturated fatty acids (20.58–25.87%). Palmitic acid, docosahexaenoic acid (DHA) and oleic acid were the most abundant fatty acids in the flesh of all species, with values in the range of 19.69–24.05%, 18.49–20.48% and 11.62–15.75%, respectively. The flesh of all fish contained almost similar levels of omega-3 polyunsaturated fatty acids (omega-3 PUFA), ranging from 26.60 to 27.08%. The majority of these omega-3 PUFA was primarily contributed by DHA (69.51–75.63%), then eicosapentaenoic acid (EPA, 13.98–17.52%). These results demonstrate that the three species of tuna studied in the present work are excellent sources of protein and the health-beneficial omega-3 polyunsaturated fatty acids

Antimicrobial Activity of Various Plant Extracts on Pseudomonas Species Associated with Spoilage of Chilled Fish

The antimicrobial activity of various plant extracts on Pseudomonas bacteria isolated from spoiled chilled tilapia (Oreochromis sp.) was evaluated in this study. In the first stage of this study, red tilapia was subjected to chilled storage (4°C) for 3 weeks, and spoilage bacteria were isolated and identified from the spoiled fish. Pseudomonas was the dominant bacteria isolated from the spoiled fish and further identification revealed that P. putida, P. fluorescens and Pseudomonas spp. were the main species of this group. In the second stage, methanolic extracts of 15 selected plant species were screened for their antimicrobial activity, by agar disc diffusion method, against the Pseudomonas isolates. Results indicated that most of the extracts had different degrees of activity against the bacterial isolates. The strongest activity was exhibited by bottlebrush flower (Callistemon viminalis) extract. This was followed by extracts from guava bark (Psidium guajava) and henna leaf (Lawsonia inermis). Moderate antimicrobial activities were observed in extracts of clove (Syzygium aromaticum), leaf and peel of tamarind (Tamarindus indica), cinnamon bark (Cinnamomum zeylanicum), wild betel leaf (Piper sarmentosum) and fresh thyme (Thymus spp.). Weak or no antimicrobial activity was observed from the remaining extracts. The potential antimicrobial activity shown by some plant extracts in this study could significantly contribute to the fish preservation