Browsing by Author "Mohamad N. Azra"

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    Digestive enzyme profiles from foregut contents of blue swimming crab, Portunus pelagicus from Straits of Johor, Malaysia
    (Journal of the Association of Arab Universities for Basic and Applied Sciences, 2016-10-17) Ambok-Bolong Abol-Munafi; Nordiana Pilus; Roswati Md Amin; Mohamad N. Azra; Mhd Ikhwanuddin
    This study describes the digestive enzyme profiles from foregut contents of the blue swimming crab, Portunus pelagicus (L.), from Straits of Johor, Malaysia. Adult male (mature and immature) and female (ovarian maturation stages 1–4) blue swimming crabs were assayed for the presence of digestive enzymes (protease, trypsin, amylase and lipase) in the foregut. The results show that in some instances, significant differences in enzyme activities were observed between the sexes of P. pelagicus. Protease, trypsin, and amylase were detected in all gonad maturation stages, suggesting that crabs including immature males can readily digest dietary protein and carbohydrates, but not lipids. Trypsin (except for ovarian maturation Stage 4) and lipase (ovarian maturation Stage 4 and mature male only) activities were considerably higher than amylase, indicating that dietary proteins and lipids are more important than carbohydrates and, thus, suggests a carnivorous diet. In conclusion, the changes in enzyme activities between the different maturation stages and sexes reflect natural changes in diet and feeding abilities of P. pelagicus.
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    Effects of various microalgae on fatty acid composition and survival rate of the blue swimming crab Portunus pelagicus larvae
    (Indian Journal of Geo-Marine Sciences, 2016) Mhd Taufik; Zainuddin Bachok; Mohamad N. Azra; Mhd Ikhwanuddin
    Present study is to examine effect of various microalgae on Fatty Acid (FA) of Portunus pelagicus larvae. Larvae were subjected to five different treatments; T1, T2, T3, T4 and T5. T1: rotifer and Artemia only; T2: rotifer, Artemia and Chaetoceros sp.; T3: rotifer, Artemia and Chlorella sp.; T4: rotifer, Artemia and Isochrysis sp. and T5: rotifer, Artemia and Nannochloropsis sp. Highest FA component in Zoea 3 was saturated FA group of T2 with concentration 26.06±26.23mg/g. For monounsaturated FA group, highest FA component in Zoea 1 was T5 with concentration 9.88±0.34mg/g. FA component in polyunsaturated FA group in Zoea 4, T4 with concentration 9.33±0.45mg/g was highest. For survival rate, highest survival rate obtained from T4 with 10.21%±0.45. In this study, essential FA requirement in each stage of P. pelagicus larvae can be reveal. Species of microalgae suitable for larvae can be characterized and selected for hatchery purpose.