Responses of diploid and triploid Pacific oysters Crassostrea gigas to Vibrio infection in relation to their reproductive status
|Author(s)||De Decker Sophie2, Normand Julien2, Saulnier Denis2, Pernet Fabrice3, Castagnet Sophie2, Boudry Pierre1|
|Affiliation(s)||1 : IFREMER, Lab Physiol Invertebres, F-29280 Plouzane, France.
2 : IFREMER, Lab Genet & Pathol, F-17390 Ronce Les Bains, La Tremblade, France.
3 : IFREMER, Lab Environm Ressources Languedoc Roussillon, F-34203 Sete, France.
|Source||Journal Of Invertebrate Pathology (0022-2011) (Academic Press Inc Elsevier Science), 2011-02 , Vol. 106 , N. 2 , P. 179-191|
|WOS© Times Cited||28|
|Keyword(s)||Experimental vibriosis, Crassostrea gigas, Vibrio, Survival distribution function, Triploidy, Reproductive effort|
|Abstract||Several Vibrio species are known to be pathogenic to the Pacific oyster Crassostrea gigas. Survival varies according to pathogen exposure and high mortality events usually occur in summer during gametogenesis. In order to study the effects of gametogenetic status and ploidy (a factor known to affect reproduction allocation in oysters) on vibriosis survival, we conducted two successive experiments. Our results demonstrate that a common bath challenge with pathogenic Vibrio splendidus and Vibrio aestuarianus on a mixture of mature, spawning and non-mature oysters can lead to significant mortality. Previous bath challenges, which were done using only non-mature oysters, had not produced mortality. Immunohisto-chemical analyses showed the affinity of Vibrio for gonadic tissues, highlighting the importance of sexual maturity for vibriosis infection processes in oysters. Mortality rate results showed poor repeatability between tanks, however, in this bath challenge. We then tested a standardized and repeatable injection protocol using two different doses of the same combination of two Vibrio species on related diploid and triploid oysters at four different times over a year. Statistical analyses of mortality kinetics over a 6-day period after injection revealed that active gametogenesis periods correspond to higher susceptibility to vibriosis and that there is a significant interaction of this seasonal effect with ploidy. However, no significant advantage of triploidy was observed. Triploid oysters even showed lower survival than diploid counterparts in winter. Results are discussed in relation to differing energy allocation patterns between diploid and triploid Pacific oysters. (C) 2010 Elsevier Inc. All rights reserved.|