The effect of lipid level on the growth and reproductive performance of female orange mud crab, Scylla olivacea (Herbst, 1796), during the fattening period

Abstract

This experiment aimed to evaluate the efficiency of formulated feeds with different lipid levels (T1 = 60 g/kg, T2 = 80 g/kg, T3 = 100 g/kg and T4 = 120 g/kg) in the biochemical composition of female orange mud crab, Scylla olivacea, during the fattening period. Experiments were conducted on 120 crabs with BW and CW of 186.42 ± 37.90 g and 10.24 ± 0.66 cm, respectively, for 90 days. The crabs were reared in tanks, and dissections were performed in 10 individuals per treatment every 30 days. Overall assessments disclosed that mud crabs fed the T4 showed the highest BWG (1.80 ± 0.78 g, 13.78 ± 1.81 g and 14.51 ± 3.81 g), SGR (0.03 ± 0.02%day−1, 0.19 ± 0.01%day−1 and 0.28 ± 0.02%day−1), GSI (9.90 ± 1.05%, 11.31 ± 1.68% and 17.30 ± 2.13%) and HSI (4.17 ± 0.52%, 5.22 ± 0.40% and 5.06 ± 0.45%) during fattening periods. Meanwhile, EPA and DHA were the most important fatty acids required for maturing ovaries in mud crabs. During 60- and 90-day culture period, higher EPA and DHA were noted in the ovary of mud crabs fed with T4 (EPA: 4.79 mg/g and 6.69 mg/g; DHA: 4.55 mg/g and 6.85 mg/g) compared with hepatopancreas (EPA: 1.84mg/g and 2.47 mg/g; DHA: 3.28 mg/g and 3.71 mg/g) (p < .05). The low fatty acid composition in the hepatopancreas indicates a nutrient transfer from the hepatopancreas to the ovaries for maturation. Two-way ANOVA suggested that 120 g/kg of feed with 60–90 days of duration would be the best for crab rearing.