Data/hora: 13/06/2024 06:29:13

Provedor de dados: | 5
País: | France
Título: | Affinage des huîtres creuses Crassostrea gigas en claires ostréicoles du Bassin de Marennes-Oléron : Etude des modifications de la Norme AFNOR-NF V 45 056
Autores: | Robert, Stephane; Goulletquer, Philippe; Soletchnik, Patrick; Geairon, Philippe; Le Moine, Olivier; Razet, Daniel; Faury, Nicole; Taillade, Sylvie.
Data: | 1998-12
Ano: | 1998
Palavras-chave: | Huître creuse; Crassostrea gigas; Affinage; Claires ostréicoles; AFNOR NF V 45-056; Pacific Cupped oyster; Crassostrea gigas; Growth; Oyster ponds; AFNOR NF V 45-056.
Resumo: | Within its oyster quality project, the Marennes-Oleron Professional Organization (SRC) aims to improve the zootechnic rearing conditions in ponds for the Pacific cupped oyster C. gigas "fines de claires" and "speciales de claires", presently specified by the French norm AFNOR NF V45-056 (AFNOR, 1985). The proposed modifications concern a seasonal management of the oyster biomass per m2 , using 1 and 3kg/m2, during 2 weeks from April 1rst to October 31, and 3 weeks from November 1 to March 31, respectively. The Shellfish Aquaculture Laboratory of Poitou-Charentes (LCPC) carried out experiments to address the professional and decision-makers request for an assessment of those modifications on the final oyster quality compared to the current rearing conditions. The experiments were based upon the expertise obtained from 1994 to 1997 by developing the research program entitled 'Oyster Ponds Valorization' and concerned two oyster growth monitorings during two seasons. Three variables were taken into account: 1) initial condition index, as specified by AFNOR index, 2) rearing time, and 3) biomass/m2. To test the 'initial condition index' effect, oyster batches showing various AFNOR index values were selected with similar age and size. Oyster batches were compared using the same early deployment time into ponds. Results were consistent with our 1994-1997 experiments, showing optimized condition by using the modified norm. This resulted mainly from the reduced rearing time in oyster ponds, therefore limiting oyster thinning and mortality rates. Basically, oyster thinning was correlated with increased lasting time in ponds. The rearing time to obtain the 'speciales de claires' brand (8 weeks) was not compensated by the reduced oyster density. In contrast, increased oyster biomass was compensated by the limited time in oyster ponds during the 2nd experiment. The initial condition index was critical for the final results and no AFNOR class downgrading resulted from using the modified norm. However, experiments were carried out using high condition index, ranging from 9 to 14. Proximate biochemical composition for ail oyster batches was modified by their stay in ponds. The decreasing AFNOR index was concomitant to an increased proteins and decreased lipids concentration. With regard to carbohydrates, 'speciales de claires' and 'new norm' were the most and least affected classes respectively. Environmental conditions were not stressful for oysters until end of March. Oxygen concentrations were not stressful for oysters over the experimental time. However, annual variability, and a likely early temperature increase would sensitize oysters at a 3 kg/m2 biomass in March due to resulting oxygen decrease. Therefore, lasting time in ponds and initial condition index remain the critical parameters for oyster rearing in those ponds which were eventually optimized by using the proposed 'new norm'. This advantage resulted from shorter rearing period in ponds. With a limited time in ponds, condition indices were at least similar between "speciales de claires" and "new norm" oysters. For both experiments, glycogen concentration trends were comparatively optimised by using the 'new norm' rearing conditions.
Tipo: | Text
Idioma: | Francês
Identificador: | http://archimer.ifremer.fr/doc/00102/21325/18948.pdf
Relação: | http://archimer.ifremer.fr/doc/00102/21325/
Formato: | application/pdf
Fonte: | 1998 Ifremer