Morphological, Histological, and Physiological Responses of Female Orange Mud Crab, Scylla olivacea (Herbst, 1796), Fed with Different Dietary Lipid Levels

Abstract

The main focus of the study was to assess the effect of lipid levels on the reproduction of the female orange mud crab, Scylla olivacea. Four isonitrogenous feed (~420 g/kg) were formulated with different lipid percentages: T 1 = 60 g / kg , T 2 = 80 g / kg , T 3 = 100 g / kg , and T 4 = 120 g / kg . A feeding trial was carried out on 120 matured female mud crabs for 90 days with 30 replicates in each treatment. Based on the morphological, histological, and hormonal analysis of each crab, the performances of each experimental diet were tested. The results of the experiment disclosed positive body weight gain (BWG) and specific growth rate (SGR), with the highest value recorded in crabs that were fed T4 (BWG: 14.43 ± 1.14 g ; SGR: 0.10 ± 0.01 % da y − 1 ). The highest gonado-somatic index (GSI) and hepato-somatic index (HSI) were noted in mud crabs that were fed T4, each with a value of 14.51 ± 1.13 % and 5.23 ± 0.55 % , respectively ( P < 0.05 ). The histological assessment revealed that the highest oocyte diameter was recorded in mud crabs fed T4 ( 192.80 ± 21.93 μm), where the oocyte diameter was correlated with the progesterone (Pg) concentrations in the ovary with r = 0.73 . Evidence also indicated that Pg and estradiol (E2) are important in the ovarian development in S. olivacea and their concentrations were affected by the lipid levels. An overall analysis revealed that 120 g/kg of lipid in the diet contributes to optimal reproductive performance in Scylla olivacea. Yet, a further experiment is expected to be carried out in the future to determine the nutrient-dose response as 120 g/kg lipid may not be the optimum lipid level for reproductive and growth performance in S. olivacea. Moreover, the extrapolation of data from this study can be used as guidelines in feed formulation for developments in future research in adult crustaceans.

Effects of Dietary Lipid Levels on Growth and Gonad Development of Onychostoma macrolepis Broodfish

“…The present research is the first to study the effect of dietary lipid levels on gonad development of O. macrolepis broodstock. The current results showed that no significant differences were noted in the histological features of ovary sectioning in O. macrolepis broodstock among five dietary groups; a similar result was found in orange mud crabs' ovaries [57]. While in Chinese sturgeon, higher dietary lipid levels improved ovarian development, with a higher percent of mature oocytes and larger giant oocyte (diameter), especially for the 24-month feeding period [58].…”

The Role of Cholesterol during the Ovarian Maturation and Lipid Metabolism of Female Chinese Mitten Crab (Eriocheir sinensis)

“…Similarly, in this study, we also found that long-term feeding of a diet with 0.27% cholesterol can significantly improve the BW, HSI, and GSI of Eriocheir sinensis. BW, HSI, and GSI are three important indexes in the process of broodstock breeding, which can directly determine the reproductive performance [10,31]. In addition, cholesterol has no significant effect on the CF and MY of crabs, but the SR of cholesterol deficiency group is significantly reduced.…”

“…The broodstock nutrition of shrimp and crab has always been a weak point in the study of aquatic nutrition. Currently, research on the nutrition of shrimp and crab is mostly focused on the juvenile stage [10][11][12][13][14]. However, shrimps and crabs have different nutrient requirements at different growth stages, especially during the ovarian development stage, the broodstock needs to accumulate a large amount of nutrients to meet the requirements of ovarian development [9,15,16].…”

Evaluation of common natural diets used in female orange mud crab, Scylla olivacea (Herbst, 1796) reared in captivity

“…The histological study was done based on the standard histological procedure previously done by Aaqillah-Amr et al (2022). Meanwhile, fatty acid analyses were carried out in both ovary and hepatopancreas following the one-step method analysis by Abdulkadir and Tsuchiya (2008).…”

“…Meanwhile, the morphological analysis of the ovary was based on the measurement of the gonadosomatic index (GSI) following de Vlaming et al (1982). All calculations were as followed:The histological study was done based on the standard histological procedure previously done by Aaqillah‐Amr et al (2022). Meanwhile, fatty acid analyses were carried out in both ovary and hepatopancreas following the one‐step method analysis by Abdulkadir and Tsuchiya (2008).…”