This study describes the fatty acids, total carotenoids, and cell diameter characteristics of the female ovary and hepatopancreas of the mud crab, Scylla olivacea, with comparisons at different ovarian maturation stages. Seventy-one S. olivacea individuals at all stages of ovarian maturation were sampled from the Setiu wetlands, Terengganu, Malaysia. The ovary and hepatopancreas of each crab were used for morphological studies, histological and biochemical analyses (fatty acid composition and total carotenoids). Morphological observations indicated there was an increase in ovarian gonado-somatic index (GSI), with color changes from translucent to dark red; however, a relatively consistent hepato-somatic index (HSI) in the hepatopancreas, with the color ranging from yellow to yellowish-brown. Histological analysis indicated that oocyte diameter was positively correlated with GSI. Hepatopancreatic tubules had a relatively constant diameter from Stage 2 to 4, with increased proportions of R- and B-cells. Biochemical analysis indicated there was a significant increase in total carotenoids in the ovary during maturation. The hepatopancreas, however, had relatively consistent total carotenoid concentrations that were greater than those of the ovary. Overall, the lipid analysis results indicated there were lesser concentrations of fatty acids in the hepatopancreas, while in the ovary there were increasing concentrations during maturation. The lesser concentrations of fatty acids in the hepatopancreas than ovary suggested that energy was transferred to the ovary for future embryonic and larval development. The relationship between the hepatopancreas and the ovary in nutrient content is an important finding in providing a baseline to formulate an optimal diet for improved mud crab hatchery practices.
Understanding Macrobrachium rosenbergii ovarian maturation control at the genome level is an important aspect for increasing larvae production. In this study, an ovarian maturation related gene, M. rosenbergii vWD domain and three Kazal-type domains of a gene (MrvWD-Kazal) have been studied. The MrvWD-Kazal gene was isolated using a rapid amplification of cDNA end (RACE) method and the relative abundances of MrvWD-Kazal mRNA in the ovary, hepatopancreas, stomach, intestine and gill were determined by using the quantitative PCR technique. The MrvWD-Kazal gene is composed of 2194 bp with an open reading frame (ORF) of 1998 bp encoding 665 amino acids and has great similarity to the M. nipponense vWD-Kazal gene (91%). The qPCR analyses indicated the relative abundance of MrvWD-Kazal mRNA transcript varied among different stages of ovarian function (P < 0.05), but there were no differences abundance in hepatopancreas, stomach, intestine and gill (P> 0.05). In the ovary, relative abundance of MrvWD-Kazal mRNA transcript gradually increased with ovarian maturation from Stages 1 (Spent; 1.00-fold), to 2 (Proliferative; 3.47-fold) to 3 (Premature; 6.18-fold) and decreased at Stage 4 (Mature; 1.31-fold). Differential relative abundances of MrvWD-Kazal mRNA transcript in the ovary indicate the MrvWD-Kazal protein may have an important function in ovarian maturation of M. rosenbergii. The results of this study also indicate the MrvWD-Kazal is not involved in regulation of the reproductive related function of the hepatopancreas, digestive system (stomach and intestine) and respiratory system (gill).
Matched MeSH terms: Hepatopancreas/growth & development