In vitro cultivation of Maritrema novaezealandensis (Microphallidae): the effect of culture medium on excystation, survival and egg production.

In this study, the effect of the composition of culture medium on excystation, growth, survival and egg production was investigated for the recently discovered microphallid trematode Maritrema novaezealandensis. Metacercariae from the two second intermediate crab hosts, Macrophthalmus hirtipes and Halicarcinus whitei, were incubated in either: (1) 0.85% saline solution, (2) the commercial cell culture medium, NCTC-109, (3) NCTC-109 supplemented with 20%, or (4) NCTC-109 supplemented with 40% chicken serum. Furthermore, excysted metacercariae were cultured for 5 days in each of the three media: NCTC-109 and NCTC-109 supplemented with 20% or 40% chicken serum. Excystment was rapid for all media used in the experiment. However, metacercariae in 0.85% saline solution had a significantly lower excystment rate over the first 4 h of incubation compared to the other media. Egg production was highest in specimens cultured in media with a supplement of chicken serum and reached a maximum after 2 days of cultivation. Growth, however, did not occur after the first day of cultivation in any of the three media.