Fatty Acid Composition of Hepatopancreas and Gonads in Both Sexes of Orange Mud Crab, Scylla olivacea Cultured at Various Water Flow Velocities.

Muhammad Taufik,Mhd Ikhwanuddin,Ambok Bolong Abol-Munafi,Ismail Shahrul,Abdul Rahman Mohd Nordin

doi:10.21315/tlsr2020.31.2.5

Abstract

Nutritional quality of the hepatopancreas and gonads of orange portunid mud crab, Scylla olivacea was evaluated for each gender under four treatment of different water velocities (0, 20, 40 and 60 cm s−1), in terms of nutrient reserve and nutrient for reproduction. About 56 crabs were used in this study in which fatty acids composition was analysed using gas chromatography mass-spectrometry (GC-MS). For hepatopancreas analysis, monounsaturated fatty acids (MUFAs) were present in the highest fatty acids concentration, followed by polyunsaturated fatty acids (PUFAs) and, saturated fatty acids (SFAs). However, long-chain polyunsaturated fatty acids (LC-PUFAs) were displayed in low concentration in the hepatopancreas. Total fatty acid (TFAs) composition was significantly higher at moderate velocity of 20 cm s−1 compared to other water velocity treatments. For gonad analysis, 20 cm s−1 showed the highest TFA concentration of 93.34 mg g−1 while, the lowest concentration of 3.90 mg g−1 occurred at 0 cm s−1. There were significant differences in male and female crab’s fatty acids contents of gonads at all flow velocities challenged (p < 0.05). PUFAs and MUFAs were dominant while, SFAs were observed at low concentration. This study revealed that, concentration of PUFAs increased as gonad maturation increased. The decreasing concentration of hepatopancreas fatty acids over the culture period indicated that nutrient was shifted from the hepatopancreas, to be used as energy reserved to gonads for further growth of eggs and offspring. The linkages between water flow strength, hepatopancreas, and gonad fatty acids concentrations, is fundamental knowledge useful in establishing efficient habitat velocities selection which will improve aquaculture production of mud crabs with high quality broodstock.

Highlights

Basic knowledge of how water velocities employed in rearing systems may impact the physiology of culture species is crucial to enhance the management of reproductive development in broodstock, especially with respect to recirculating aquaculture systems (RAS) or, indoor culture systems
Nutritional value of fatty acids is crucial to the diet of cultured species and, they exert a major impact on other vital requirements such as survival, spawning, and repair of damaged tissue (Amran et al 2018)
At velocity 20 cm s–1, monounsaturated fatty acids (MUFAs) was highest with the range of 0.70 to 35.07 mg g–1, SAFAs with a range of 1.30 to 16.70 mg g–1 and, polyunsaturated fatty acids (PUFAs) with a range of 0.90 to 9.27 mg g–1

Summary

Introduction

Basic knowledge of how water velocities employed in rearing systems may impact the physiology of culture species is crucial to enhance the management of reproductive development in broodstock, especially with respect to recirculating aquaculture systems (RAS) or, indoor culture systems. The portunid crab (genus Scylla) is in high demand as a global aquaculture species because of its high price, unique flavour, high meat yield, rigid muscle and sweet flesh (Ikhwanuddin et al 2015; Abol-Munafi & Azra 2018; Kunsook & Dumrongrojwatthana 2017; Ikhwanuddin et al 2018). Hepatopancreas is the main tissue where fatty acids are reserved. The hepatopancreas fatty acids change when crabs mature (Abol-Munafi et al 2016). The hepatopancreas reserves energy for survival, shedding and reproduction (Sarapio et al 2017) and, acts as a store for vitellogenin (Wang et al 2014; Liu et al 2018).

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