Ekonomska efikasnost dodavanja maltoze u ishrani mlađi nilske tilapije (оrеоchrоmis nilоticus)

Diets developed for aquaculture require good stability to avoid dissolution from exposure, especially carbohydrates. Five experimental diets were formulated to contain different maltose levels (20, 25, 30 and 35%). Maltose retention at 15, 30, and 60 minutes was investigated in the laboratory. The result of the experiments showed that maltose leaching increased by increasing time of immersion (30 min),and it was 100% for feed 20, containing25% maltose, and 95% for feed 30,containing 35% maltose. The growth was correlated to the data produced from the leaching of dietary maltose, and significant differences (P < 0.05) in mean final weight and mean weight gain between groups have been recorded. The fish fed diet which contained 35% maltose achieved the best growth, economic efficiency and relative economic efficiency comparing with other tested diets.Hrana koja se proizvodi zа аkvаkulturu zаhtеvа dоbru stаbilnоst, kаkо bi sе izbеglо njeno rаspаdаnje u toku primene, nаrоčitо uglјеnih hidrаtа. Pеt еkspеrimеntаlnih hrаna je fоrmulisаno tаkо dа sаdrže rаzličitе količine mаltоze (20, 25, 30 i 35%). Postojanost maltoze u toku 15, 30, i 60 minutа ustanovljeno je u lаbоrаtоrijskim uslovima. Ekspеrimеntalni rеzultаti su pоkаzаli dа se natapljenost mаltоzom povećava sa pоvеćаnjеm vrеmеnа potapanja (30 min) i bilo је 100% zа hrаnu 20, sa 25% mаltоze i 95% zа hrаnu 30, sa 35% mаltоzе. Porаst је bio u kоrеlаciјi sа podacima koji su dobijeni za natapanje diјеtеtske mаltоze, а ustanovljene su znаčајnе rаzlikе (p <0,05) u srednjim vrednostima finalne mase kao i u prirastu srednjih vrednosti masa između grupa. Ribа koja je hranjena hranom koja je sаdržala 35% maltoze оstvаrilа je nајbоlјi prirаst, еkоnоmsku еfikаsnоst i rеlаtivnе еkоnоmskе еfikаsnоsti u pоrеđеnju sа drugim ispitanim hranama

Production of Cellulose from Barley Husks as a Partial Ingredient of Formulated Diet for Tilapia Fingerlings

Cellulose is the most abundant renewable polysaccharide on earth and it is widely used in many aspect and industries such as food industry, pharmaceutical, and many more. Due to the increasing demand in the market, studies and work to produce cellulose are still rapidly developing. In this study, barley husks was pretreated in hot water at 100°C and followed with liquid oxidation process with 30% H2O2 at 60°C. Through the hot water treatment, cellulose in the barley husks was successfully recovered as glucuronic acid, saccharides, cellulose and thus leaving fats. Results obtained also show that after treatment, the barley husks is made up 66.00% cellulose. This cellulose can be used as source of the digestible carbohydrate in fish feed which can help in reducing the cost of feed production. Keywords: Barley husks, hot water treatment, liquid phase oxidation, cellulos

The embryonic development of orange mud crab, Scylla olivacea (Herbst, 1796) held in the captivity

This study attempts to observe and record early embryonic developments of the orange mud crab, Scylla olivacea. The period taken by the eggs to hatch was 8 days and the colour of the eggs gradually changed from yellow to brown, gray and dark gray. During the embryonic development, the developing embryos reached the blastula stage within 24 hours with a mean egg diameter of 329.91 ± 6.62 µm. The embryo developed into the gastrula stage on the 2nd day with a mean egg diameter of 337.10 ± 8.37 µm. Eyes were consequently observed on the 3rd day and there was a further increase in the yolk-free portion with a mean egg diameter of 338.16 ± 6.57 µm. On the 4th day, the eye-spot became crescent and there was a clearer tissue formation with a mean egg diameter of 358.45 ± 14.80 µm. Meanwhile, on the 7th day prior hatching, there were many chromatophores present, mostly dark in colour and the yolk granules had further reduced in size. The heart beats faster than previous days before and the embryo occupied most of the available egg volume with a mean egg diameter of 377.26 ± 11.50 µm

Natural diet of blue swimming crab, portunus pelagicus at Strait of Tebrau, Johor, Malaysia

Knowledge of natural diet in Portunus pelagicus is essential to understand its nutritional requirements, its interactions with other organisms and its potential for culture. The natural diet of P. pelagicus was studied in Strait of Tebrau, Johor, Malaysia via gut content analysis and molecular analysis. A total of 30 identifiable fatty acids were detected in foregut content of P. pelagicus. Fatty acid 18:3ω3 act as a mangrove detritus marker was found to be the most abundant in foregut content of both sexes of P. pelagicus and has higher value in female. PUFA was the main fatty acid found in foregut content of P. pelagicus and major contributed by fatty acid 18:3ω3, 20:5ω3 and 22:6ω3. Marine animal’s marker was found to be the dominant in foregut content of P. pelagicus and that indicated that marine animals were the main food source of P. pelagicus. In conclusion, this study showed that P. pelagicus is a primarily omnivores crab with preference of marine animal and with addition and/or incidental fed plant items

Metabolomic analysis of marine and mud crabs based on antibacterial activity

Isolated compounds from marine invertebrates are being increasingly known to possess various pharmacological activities with which many useful drugs have been developed. Crabs contain bioactive compounds including antibacterial, antifungal and antiviral metabolites, isolated from various tissues and organs that have revolutionized treatment of serious diseases. The present study represents the first attempt to investigate and compare the natural antibacterial properties from whole extract of marine blue swimmer crab, Portunus pelagicus, and mud crab, Scylla tranquebarica, against fish pathogenic bacteria. Liquid chromatography/mass spectrometry utilizing a time-of-flight (TOF) mass analyser (LC/MS-QTOF) based metabolomics approach was used to characterize the variation in secondary metabolite production in P. pelagicus and S. tranquebarica crab habitats in Malaysia. Different metabolites are evaluated in both crab species using LC/MS-QTOF. Initially a total of 75 metabolites were identified and only 19 metabolites satisfied the P-Corr cut-off point of less than 0.01 and at least 2-fold change. These metabolites, which contain anti-inflammatory and antibacterial properties, were down regulated in S. tranquebarica samples and up regulated in P. pelagicus samples. In vitro bioassay of methanolic P. pelagicus extracts showed the best antimicrobial response against Gram positive bacteria, Streptococcus agalactiae, and Gram negative bacteria, Vibrio alginolyticus, Klebsiella pneumoniae, and Escherichia coli, with a statistically significant difference (P < 0.05) of P. pelagicus extracts as compared to S. tranquebarica. The results indicate that both types of crab extracts are bactericidal at higher concentrations and bacteriostatic at lower concentrations. This manuscript reports the role of marine and mud crabs with specific emphasis on their secondary metabolites, and discusses current and future developments in both the production of desired crab metabolites and their potential uses in pharmaceutical industries