Is spermatophore melanisation in captive shrimp (Litopenaeus vannamei) a result of an auto-immune response?

Structural alterations in the male reproductive system of the freshwater crayfish, Cherax quadricarinatus (Decapoda, Parastacidae)

“…Further analysis will be needed to confirm the absence of bacteria in the melanised spermatophores for C. quadricarinatus. However, Dougherty and Dougherty (1989) and Diamond et al (2008) did not find haemocytes in the reproductive tract either, in contrast to our study. Talbot et al (1989) characterized the syndrome as male reproductive tract degenerative syndrome (MRTDS) because it was present along the reproductive system of the shrimp.…”

“…As concerns the sperm count, no differences between brownish and normal spermatophores were found in C. quadricarinatus, as in P. muelleri (Díaz et al, 2001) and L. vannamei (Diamond et al, 2008), in contrast to the results reported by Chamberlain et al (1983) and Pascual et al (1998) for L. setiferus, L. vannamei and P. stylirostris. Under light microscope magnification, we did not observed abnormal sperm as was reported for L. vannamei (Dougherty and Dougherty, 1989;Diamond et al, 2008) and L. setiferus (Talbot et al, 1989).…”

“…In accordance to the reported by Talbot et al (1989) in the shrimp L. setiferus, we did not found black spermatophores in C. quadricarinatus, but different degree of colour from a very light tan to a dark brown colour. Dougherty and Dougherty (1989) and Diamond et al (2008) reported that they did not found any bacteria in the histological sections under light and electron microscopy (Dougherty and Dougherty, 1989) and in bacterial counts from agar plates (Diamond et al, 2008) of melanised vas deferens for L. vannamei. Since the presence of bacteria could be identified histologically only if they were present in great numbers, we are not able to discard their presence (e.g.…”

“…It is characterised by a reduction in sperm count and sperm viability leading to male infertility (Chamberlain et al, 1983;Leung-Trujillo and Lawrence, 1987;Pascual et al, 1998;Rosas et al, 2004 for revision). It is thought to be produced by stress, bacterial infection, inappropriate diet or problems of endocrine nature associated with environmental stress (Alfaro and Lozano, 1993;Chamberlain et al, 1983;Diamond et al, 2008;Dougherty and Dougherty, 1989;Leung-Trujillo and Lawrence, 1987;Rosas et al, 1993;Rosas et al 2004). This syndrome is usually referred as ''male reproductive tract degenerative syndrome" (Diamond et al, 2008;Talbot et al, 1989;Rosas et al, 2004 for revision) and its aetiology remains unknown.…”

“…Among other factors, it has been demonstrated that diseases affect the reproductive system, decreasing the reproductive performance. The darkening of the spermatophore, also named melanisation, was found in the reproductive system of males of the penaeid shrimps Litopenaeus setiferus Bray et al, 1985;Brown et al, 1979;Chamberlain et al, 1983;LeungTrujillo and Lawrence, 1987;Pascual et al, 1998;Rosas et al, 2004;Talbot et al, 1989), Litopenaeus vannamei (Alfaro and Lozano, 1993;Chamberlain et al, 1983;Diamond et al, 2008;Dougherty and Dougherty, 1989;Parnes et al, 2006;Perez Velazquez et al, 2001), Penaeus stylirostris (Chamberlain et al, 1983) and Pleoticus muelleri (Díaz et al, 2001), and in the caridean shrimp Macrobrachium rosenbergii (Harris and Sandifer, 1986). It is characterised by a reduction in sperm count and sperm viability leading to male infertility (Chamberlain et al, 1983;Leung-Trujillo and Lawrence, 1987;Pascual et al, 1998;Rosas et al, 2004 for revision).…”