Data/hora: 05/06/2024 18:45:36

Provedor de dados: 	5	
País: 	France	
Título: 	Caractérisation précoce de la mortalité des lignées divergentes de Crassostrea gigas (G2)	
Autores: 	Degremont, Lionel; Soletchnik, Patrick; Doner, Anne.	
Data: 	2002-06-13	
Ano: 	2002	
Palavras-chave: 	Mortalités; Sélection; Physiologie; Genetique; Crassostrea gigas; Huîtres.	
Resumo: 	2001 shows how important the "R" and "S" biological families are for experimentation as well as the need to "preserve" these families from mortality during the first year. The "experimental nursing" conditions do not allow the conservation of dozens of families with many members for 6 to 8 months. Precocious characterisation at around 4-5 months enables a first selection of the biological material, as well as a first answer to the "in lab" genetical selection of the families. After the first results in 2001 (Céline de Ambroggi, LCPC, L. Degremont), two "precocious characterisation of mortality" experiments are carried out in 2002 on the divergent lineage of some genetical families (LGP production). Two 15 day long experiments are conducted in la Tremblade from June 13th, 2002 (exp. 1) to July 04th, 2002 (exp.2). 23 then 16 second generation families are tested. Families are placed in trays and polyester raceways (experiment 1) and raceway and norten basket (experiment 2). Oysters are counted 2-3 times a week. After 7 days a 2 hours and 40° thermic stress is administered to the oysters in order to quicken the mortality answer (experiment 1). Oxygen, salinity and temperature are measured on a daily basis during these experiments. Despite 8 families missing during the second experiment, table 2 takes into account the ranks from the LSD tests of the variance analysis of the normalised mortality rates. If some sensitive (K, N, P) and resisting ("R") families present average mortality rates for this batch or mitigated rates according to the experiment, other "resisting" (A, D, H) or "sensitive" (AB, M, W) families, confirm, during the second experiment, the first results. During the second test, the thermic stress is administered after 7 days. 6 days later, mortality rates reach 15, 23 and 33% for the "resisting", "control" and "sensitive" stocks. During the second experiment, without thermic stress, equivalent mortality is reached in 17 days, with rates of 9, 27 and 35 % for the "resisting", "control" and "sensitive" stocks Mortality can happen in a few days for those families, well characterised from a genetical point of view, and with a low genetical dispersion. As a preliminary to mortality characterisation of the genetical families on marine estuaries (Cares 2002), the results of these two experiments demonstrate the existence of a hereditary component in "mortality". Such clear-cut results also show that the hereditary factor alone cannot be responsible (Boudry, com. pers.). Other factors are implied and ad up to this hereditary component. These results confirm the 2001 experiments and show how, during the May-July period (temperature over 19-20°C, relation to maturation?), nurseries and concrete raceways are conducive to mortality	
Tipo: 	Text	
Idioma: 	Francês	
Identificador: 	http://archimer.ifremer.fr/doc/2002/acte-3406.pdf	
Editor: 	Présentation Séminaire MOREST, 13-15 novembre 2002, Brest	
Relação: 	http://archimer.ifremer.fr/doc/00000/3406/	
Formato: 	application/pdf