TBT Effects on the Development of Intersex (Ovotestis) in Female Fresh Water PrawnMacrobrachium rosenbergii

Abstract

The impact of tributyltin (TBT) on the female gonad and the endocrine system in Macrobrachium rosenbergii was studied. Prawns were exposed to environmentally realistic concentrations of 10, 100, and 1000 ng/L of TBT for 6 months. Dose dependent effects were noticed in TBT exposed prawns. At 1000 ng/L TBT caused ovotestis formation (formation of male germ cells in ovary). Presence immature oocytes, fusion of developing oocytes, increase in interstitial connective tissues, and its modification into tubular like structure and abundance of spermatogonia in the ovary of TBT treated prawns. The control prawn ovary showed normal architecture of cellular organelles such as mature oocytes with type 2 yolk globules, lipid droplets, normal appearance of yolk envelop, and uniformly arranged microvilli. On the other hand, type 1 yolk globules, reduced size of microvilli, spermatogonial cells in ovary, spermatogonia with centrally located nucleus, and chromatin distribution throughout the nucleoplasm were present in the TBT treated group. Immunofluorescence staining indicated a reduction in vitellin content in ovary of TBT treated prawn. Moreover, TBT had inhibited the vitellogenesis by causing hormonal imbalance in M. rosenbergii. Thus, the present investigation demonstrates that TBT substantially affects sexual differentiation and gonadal development in M. rosenbergii.

Zebrafish sex differentiation and gonad development after exposure to 17α-ethinylestradiol, fadrozole and their binary mixture: A stereological study

“…The most frequently reported manifestation of intersex is the presence of single or multiple oocytes which normally grow into the testis (Bahamonde et al, 2013;Nolan et al, 2001;Randak et al, 2009) which is in agreement with previous occurrences reported both in zebrafish (Brion et al, 2004;Hill and Janz, 2003;Örn et al, 2003) and in studies with similar treatments and other fish species (Afonso et al, 2001;Gao et al, 2010;Peranandam et al, 2014). This result indicates that Fad exposure, although potentiating masculinization, may at the concentration used not completely transform females into males, as some of the gonads still present oocytes, or the exposure time was not sufficient to masculinize all females as they have an asynchronous gonad maturation.…”

Effects of Organotins on Crustaceans: Update and Perspectives

“…Imposex is characterized by the formation of male sexual organs such as penis and vas deferens in these females ( 19 , 86 ). Although some studies show an early sexual reversal (intersex) in crustaceans exposed to TBT, these changes are less marked than those occurring in mollusks ( 31 , 88 ). Nevertheless, other detrimental effects on the reproductive system of different species of crustaceans were found in both females and males ( 27 , 88 – 90 ).…”

“…Although some studies show an early sexual reversal (intersex) in crustaceans exposed to TBT, these changes are less marked than those occurring in mollusks ( 31 , 88 ). Nevertheless, other detrimental effects on the reproductive system of different species of crustaceans were found in both females and males ( 27 , 88 – 90 ). The mechanism by which TBT causes these damages is still unclear, and there are different possible sites of action ( 80 , 86 , 89 ).…”

“…The stimulatory effects of steroids on crustacean reproduction are well recognized; however, it was only with the development of modern omics technology that genes of steroidogenic enzymes and putative steroid receptors were identified ( 31 , 39 , 94 – 98 ). In female M. rosenbergii , TBT reduced 17β-estradiol in the hemolymph and ovary and increased T levels in the ovary ( 88 ), while in males, TBT reduced T levels in testis ( 73 , 90 ) (Figure 2 ) ( 53 , 94 ). In crustaceans, an alternative action proposed was that TBT could block T excretion, but results are still inconclusive ( 18 , 93 , 99 , 100 ).…”

“…Unlike mollusks, when female crustaceans are exposed to TBT, there is no formation of complete male sex organs ( 31 ). Nevertheless, in M. rosenbergii , the treatment with TBT (10, 100, and 1000 ng L −1 ) for 45 days altered ovarian morphology and induced spermatogonia and ovotestis (with spermatocytes and structures similar to seminiferous tubules) ( 88 ). In the hermit crab C. vittatus , TBT induced several degrees of ovarian disorganization with follicular atresia and irregular oocytes although there was no formation of male sexual structures ( 27 ).…”