Breeding performance of Bithynia siamensis goniomphalos populations in relation to prevalence of Opisthorchis viverrini in Northeastern region of Thailand Thanathip Lamkom 1,*, Dechnarong Phosri 1 Department of Fisheries, Faculty of Agriculture, Ubon Ratchathani University, Warin chamrab, THAILAND

Opisthochiasis, together with associated cholangiocarcinoma, is one of the human parasitic diseases in lower Mekong area, e.g. Thailand, Lao PDR, Cambodia, and Vietnam (Waikagul, 1998; Sripa et al., 2011; Sitthithaworn et al., 2012). Introduction The prevalence of liver fluke infection in Thailand was found in many provinces of Northeast region. Source: Sripa et al. (2011)

Liver fluke, Opisthorchis viverrini can infect and inhabit within the intrahepatic bile ducts of human through undercooked fish (Grundy-Warr et al., 2012). Source: modified from Petney et al. (2012) Bithynia siamensis goniomphalos is recognized as the specific host of transmission in life cycle of liver fluke. Introduction

4 Bithynia siamensis goniomphalos There are 3 species in Thailand; B. funiculata, B. s. siamensis, and B. s. goniomphalos Bithynia snails are oviparous animals which can spawn eggs (3-8 eggs per set) on the natural materials (rocks and gravels). At C, the developmental period of B. s. goniomphalos eggs ranged days (Kruatrachue et al., 1982). Introduction

The habitat of B. s. goniomphalos was commonly found in the lentic waters, e.g. lakes, ponds, reservoirs and flooding area. The richness of snail populations depend on physical and chemical parameters of water quality, e.g. salinity ( ppt), water depth (30 cm), temperature ( C), and dissolved oxygen ( ppm) (Petney et al., 2012). Introduction

Objectives  To study on the breeding performance, spawning period, total number of spawned eggs, and hatching period of B. siamensis goniomphalos in 3 populations.  To study on the embryonic development of B. siamensis goniomphalos.

Materials and methods  Site selection LA = Lam pao reservoir NH = Nong harn reservoir UB = Ubonrat reservoir 1 2 3

8 Materials and methods  Bithynia samples ♂ ♀ ♂ ♀

Materials and methods  Broodstock

Materials and methods  Breeding studies male:female = 2:3 (per box) Water temperature = 28±1 0 C Light:dark = 8:16 hr

Materials and methods  Breeding studies

12 The embryonic development of Bithynia was divided into 5 stages; cleavage, morula, gastrula, trochophore, and hippo stages. The yellowish zygote was encapsulated within gelatine which protected the eggs. 1 st day 5 th day The 3-4 rows of fertilized eggs were attached tightly on the bottom of aquarium. Results

1 st hr 4 th hr 6 th hr 9 th hr 12 st hr 20 th hr 22 th hr Zygote Cleavage Morula Embryonic development

26 th hr 28 th hr 44 th hr Trochophore Veliger 54 th hr 63 h hr 69 th hr Embryonic development

Hippo 102 th hr 117 th hr 164 th hr

eye foot mouth midgut gland operculum proboscis shell stomach tentacle heart 100 µm

 Spawning period NH = 7 th -60 th (54 days) LA = 8 th -60 th (53 days) UB = 8 th -53 th (46 days) Breeding performances Figure 1 The spawned eggs per day of B. s. goniomphalos in laboratory at 28±1 0 C for 60 days.

 Total number of spawned egg NH = 580±72 eggs LA = 434±123 eggs UB = 276±76 eggs Breeding performances Figure 2 The percentage of total spawned eggs of B. s. goniomphalos in laboratory at 28±1 0 C for 60 days.

 Hatching period Breeding performances NH = 7 th -13 th (7 days) LA = 8 th -13 th (6 days) UB = 8 th -13 th (6 days) Figure 3 The hatching period of B. s. goniomphalos eggs in laboratory at 28±1 0 C.

Discussions and conclusions  The period of embryonic development in three populations ranged 7-13 days.  There are 5 stages of embryonic development; cleavage, morula, trochophora, veliger, and hippo stages.  The breeding performances, spawning period, total number of spawned egg, and hatching period, of snail samples in NH population was faster than the other populations because the environment in NH wetland can support the viable number and embryonic development.

Source: Cantacessi et al. (2013)  The increased specific host, B. s. gonionphalos can accelerate opportunity of O. viverrini prevalence. Discussions and conclusions  Kiatsopit et al. (2012) explained that the highest number of B. s. goniomphalos was found in Sakon Nakhon (NH) province. NH LA UB  Sripa et al (2011) reported that Sakon Nakhon area (NH) showed the highest incidence of cholangiocarcinoma (CCA).

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