Browsing by Author "Ivan Koh Chong Chu"

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    Effect of salinity on embryonic development and hatching of hybrid grouper, Epinephelus fuscoguttatus x epinephelus lanceolatus
    (2016) Ivan Koh Chong Chu; Borhan Nurhamizah; Zahri Noor Dee’ana; Mustafa Sufian
    Groupers are high valued finfish in the Southeast Asian regions. The hybrid grouper Epinephelus fuscoguttatus x E. lanceolatus (TGGG), is a relatively new hybrid that is in high demand due to its good taste and faster growth compared to tiger grouper E. fuscoguttatus. This study establishes and compares the optimum salinity parameters required for successful egg incubation of the two groupers. Eggs were obtained from female E. fuscoguttatus through hormone treatment of 500 IU/kg body weight of human chorionic gonadotrophin (hCG) and fertilized with sperm from E. fuscoguttatus and E. lanceolatus. Eggs were then transferred into incubation aquariums filled with 1 L water at salinities of 15, 20, 25, 30 and 35 ppt. Egg development was observed every hour till hatching occurred. Hatching rates (HR), timing and deformation rate (DR) was recorded. Stages of embryonic development showed no difference in all salinities but differing development speed was observed at certain salinities. Eggs of TGGG hatched faster than tiger grouper at identical salinities. The results indicated that eggs of both groupers had a wide range of salinity tolerance from 25-35 ppt with significantly lower HR and higher DR (P<0.05) at 15 and 20 ppt. The optimal incubation salinity was 30 ppt for TGGG (HR = 70.9±7.12%; DR = 13.3±2.35%) and E. fuscoguttatus (HR = 37.3±6.1%; DR = 20.0±2.9%). Occurrence of abnormal larvae significantly increased with suboptimal salinity.
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    Genetic Diversity in Farmed Tiger Grouper Broodstock Inferred by Partial Cytochrome b Gene
    (International Journal of Chemical, Environmental & Biological Sciences (IJCEBS), 2015) Noraini Che Hassan; Abdul Hadi Abdul Aziz; Nabilah Mohamad Ali; Nur Asma Ariffin; Ivan Koh Chong Chu; Sufian Mustafa; Shahreza Md. Sheriff
    A study was conducted to determine the genetic diversity of a farmed tiger grouper Epinephelus fuscoguttatus broodstock population located in Tanjung Demong, Terengganu using Cytochrome b (Cyt-b) gene. A total of 51 broodstock were collected and subjected to DNA extraction. PCR amplification of partial Cyt-b was conducted using a universal Cyt-b primer. The fragments were then purified, sequenced and the genetic relationship among individuals was analyzed. A total of 402 bp length of partial Cyt-b gene was obtained from each sample. Genetic distance among individuals ranged between 0.002 – 0.018. Seven haplotypes were found within the population with 2 haplotypes (Hap01 and Hap02) are commonly shared by most individuals. Phylogenetic analysis showed broodstocks is divided into two major groups. However, 47 individuals were clustered in 1 group with shallow genetic divergence. These findings indicate the tiger grouper broodstock have low genetic diversity and most of the individuals might be originating from a single population. Genetic diversity of mtDNA cyt-b of E. fuscoguttatus would be useful in tiger grouper broodstock management in breeding program for seed production.