Changes of phosphatidylcholine and fatty acids in germ cells during testicular maturation in three developmental male morphotypes of Macrobrachium rosenbergii revealed by imaging mass spectrometry.

Tanapan Siangcham,Noritaka Masaki,Mitsutoshi Setou,Takahiro Hayasaka,Saowaros Suwansa-Ard,Prasert Sobhon,Peter J Hanna,Piyachat Chansela,Morakot Sroyraya,Attakorn Engsusophon,Jaruwan Poljaroen,Shree Ram Singh

doi:10.1371/journal.pone.0120412

Abstract

Testis maturation, germ cell development and function of sperm, are related to lipid composition. Phosphatidylcholines (PCs) play a key role in the structure and function of testes. As well, increases of polyunsaturated fatty acids (PUFA) and highly unsaturated fatty acids (HUFA), especially arachidonic acid (ARA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are essential for male fertility. This study is the first report to show the composition and distribution of PCs and total fatty acids (FAs) in three groups of seminiferous tubules (STs) classified by cellular associations [i.e., A (STs with mostly early germ cells), B (STs with mostly spermatids), and C (STs with spermatozoa)], in three morphotypes of Macrobrachium rosenbergii, [i.e., small male (SM), orange claw male (OC), and blue claw male (BC)]. Thin layer chromatography exhibited levels of PCs reaching maxima in STs of group B. Imaging mass spectrometry showed remarkably high signals corresponding to PC (16:0/18:1), PC (18:0/18:2), PC (18:2/20:5), and PC (16:0/22:6) in STs of groups A and B. Moreover, most signals were detected in the early developing cells and the intertubular area, but not at the area containing spermatozoa. Finally, gas chromatography-mass spectrometry indicated that the major FAs present in the testes were composed of 14:0, 16:0, 17:0, 18:0, 16:1, 18:1, 18:2, 20:1, 20:2, 20:4, 20:5, and 22:6. The testes of OC contained the greatest amounts of these FAs while the testes of BC contained the least amounts of these FAs, and there was more EPA (20:5) in the testes of SM and OC than those in the BC. The increasing amounts of FAs in the SM and OC indicate that they are important for spermatogenesis and spermiogenesis. This knowledge will be useful in formulating diets containing PUFA and HUFA for prawn broodstocks in order to improve testis development, and lead to increased male fecundity.

Highlights

Macrobrachium rosenbergii, the giant freshwater prawn, is one of the most economically important species for global freshwater prawn farming [1,2]
We focused on the localization and quantification of PCs, and the composition of fatty acids (FAs), including polyunsaturated fatty acids (PUFA) and highly unsaturated fatty acids (HUFA), in the testes of three developmental male morphotypes of M. rosenbergii, and in during three phases of seminiferous tubules (STs) maturation which contain different stages of developing germ cells
We focused on the changes of PCs and FAs during ST maturation, and developmental stages of male morphotypes during maturation from young small male (SM) to mature blue claw male (BC) [39]

Summary

Introduction

Macrobrachium rosenbergii, the giant freshwater prawn, is one of the most economically important species for global freshwater prawn farming [1,2]. Ovarian lipid compositions, especially triacylglycerols (TAGs) and phospholipids (PLs), have been determined for Serolis pagenstecheri [7], Serolis cornuta [7], Penaeus monodon [8], Penaeus semisulcatus [9], M. rosenbergii [10], Litopenaeus vannamei [11], Fenneropenaeus indicus [12], Cherax quadricarinatus [13], Portunus sanguinolentus [14], Albunea symmysta [15], and Penaeus merguiensis [16], and indicated that lipid changes are associated with ovarian maturation and embryonic development This has provided data for formulated balanced lipid diets for females. A knowledge of lipid composition in the testes of developing males of M. rosenbergii is needed in order to formulate balanced diets for the improvement of male fecundity

Methods

Results

Conclusion