In vitro fertilization and hybridization potential of the Indian white shrimp (Penaeus indicus).

Managing the reproduction of shrimp farmed in captivity is essential for selective breeding and interspecies hybridization. Procedures have not been developed for conducting in vitro fertilization in penaeid shrimp. In this study, the feasibility of in vitro fertilization (IVF) of the pre-ovulatory oocyte of Penaeus indicus was examined. Additionally, the processes of fertilization and possibility of hybridizing P. indicus with P. monodon with utilization of IVF procedures was also evaluated. The IVF was conducted by dissecting ovaries with fully developed follicles, and mixing these (~0.1 million oocytes) with 1 mL of a sperm suspension. Evaluations for fertilization and embryonic development occurred every l5 min. The eggs collected from the ovaries had the capacity for activation and fertilization. The hatching rate was 5.5 ± 1.1% of the total number of eggs fertilized, and 8.2 ± 4.8% of the nauplii developed to the post-larval stage. Results from the scanning electron micrograph evaluations provided detailed information about the changes occurring as a result of IVF in P. indicus. Interspecific hybridization of P. indicus with P. monodon did not result in hatching of embryos from the eggs, although 1% of eggs were fertilized. A reliable and inexpensive IVF procedure was developed, therefore, IVF could be an efficacious procedure for facilitation of intraspecific cross production in a penaeid breeding program. Furthermore, it was determined that IVF could be a possible procedure for interspecies hybridization between closely related species to circumvent prezygotic barriers in reproductive processes.

Co-Infection of Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) and White Spot Syndrome Virus (WSSV) in the Wild Crustaceans of Andaman and Nicobar Archipelago, India.

The present study was intended to screen the wild crustaceans for co-infection with Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) and White Spot Syndrome Virus (WSSV) in Andaman and Nicobar Archipelago, India. We screened a total of 607 shrimp and 110 crab samples using a specific polymerase chain reaction, and out of them, 82 shrimps (13.5%) and 5 (4.5%) crabs were found positive for co-infection of IHHNV and WSSV. A higher rate of co-infection was observed in Penaeus monodon and Scylla serrata than other shrimp and crab species. The nucleotide sequences of IHHNV and WSSV obtained from crab in this present study exhibited very high sequence identity with their counterparts retrieved from various countries. Histopathological analysis of the infected shrimp gill sections further confirmed the eosinophilic intra-nuclear cowdry type A inclusion bodies and basophilic intra-nuclear inclusion bodies characteristics of IHHNV and WSSV infections, respectively. The present study serves as the first report on co-infection of WSSV and IHHNV in Andaman and Nicobar Archipelago, India and accentuates the critical need for continuous monitoring of wild crustaceans and appropriate biosecurity measures for brackishwater aquaculture.