Application of enzyme-linked immunosorbent assay (ELISA) for the study of reproduction in the Manila clam Ruditapes philippinarum (Mollusca: Bivalvia): II. Impacts of Perkinsus olseni on clam reproduction

• Published in: Aquaculture 2006-02, Vol.251 (2), p.182-191
• Main Authors: Park, Kyung-Il, Figueras, Antonio, Choi, Kwang-Sik
• Format: Article
• Language: English
• Subjects: Animal aquaculture; Animal populations; Animal productions; Animal reproduction; Aquaculture; Biological and medical sciences; clams; condition index; disease detection; disease prevalence; ELISA; enzyme-linked immunosorbent assay; Fundamental and applied biological sciences. Psychology; Gametogenesis; General aspects; gonadosomatic index; Immunoassay; Invertebrates; Korea; mollusc culture; Mollusca; Mollusks; Parasites; Perkinsus; Perkinsus olseni; protein content; Reproductive output; Ruditapes philippinarum; spawning
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2005.06.003

We investigated the effects of infection by the protozoan Perkinsus olseni on the reproduction of female Manila clams, Ruditapes philippinarum, from a population in Gomso Bay, Korea. The reproductive effort of the clams was assessed by ELISA using a clam egg-specific antibody and was expressed as a weight-based gonadosomatic index (GSI). The number of Perkinsus infecting each clam was estimated from the gills using Ray's fluid thioglycollate medium (RFTM) along with a NaOH digestion assay. We found that reproductive effort was negatively correlated with the intensity of the Perkinsus infection: more heavily infected clams produced fewer eggs during the spawning period from May to August. Frequency of spawning was also negatively correlated with the level of Perkinsus infection; heavily infected clams (HIC) exhibited a single spawning pulse in late July, whereas lightly infected clams (LIC) showed three spawning peaks in mid-May, late July, and late August. Egg production of HIC was only 30–75% of LIC during spawning. The level of total protein in LIC was also higher year round than in HIC. In conclusion, our investigation demonstrates that a high level of Perkinsus infection affects spawning frequency and reduces egg production, which may have long-term impacts on clam recruitment and population growth.