Data/hora: 13/06/2024 15:18:44

Provedor de dados: 	5	
País: 	France	
Título: 	Toxicity of ammonia to turbot juveniles: I. effects oil survival, growth and food utilisation	
Autores: 	Person-le Ruyet, Jeannine; Delbard, Christine; Chartois, Herve; Le Delliou, Herve.	
Data: 	1997-09	
Ano: 	1997	
Palavras-chave: 	Azote ammoniacal; Toxicité chronique; Taux de survie; Croissance; Alimentation; Ammonia; Chronic toxicity; Survival rate; Growth; Food efficiency; Psetta maxima.	
Resumo: 	Long-term effects of constant exogenous ammonia concentrations were investigated in two different batches of turbot juveniles (53 and 73 g) under controlled environmental and feeding conditions. Over the 84-day experiments, ambient un-ionized ammonia (UIA-N, NH3) concentrations were steady (coefficient of variation, 12-16 %) and water pH range was 7.88-7.99. Survival was maximum up to 0.33 mg.l(-1) UIA-N and at 0.73, 50 % mortalities were observed on day 52 (73 g) or day 77 (53 g). No-growth concentration was 0.73 mg.l(-1) UIA-N in the two groups and the 84-day lowest-observable-effect concentration range 0.14-0.33 mg.l(-1). In the most tolerant group (53 g), the 84-day no-observable-effect concentration was 0.14 mg.l(-1) UIA-N. The estimated 28-day efficient concentration that gave 50 % of the specific growth rate of controls ranged from 0.60 to 0.75 mg.l(-1) UIA-N. Specific growth rate to ambient ammonia concentration patterns were different in the two groups for the lowest concentrations (0.14-0.34) and similar to food intake to ammonia pattern. Food efficiency was negatively correlated to ambient ammonia concentration, with major changes in food conversion ratio, and protein utilisation observed above 0.33-0.70 mg.l(-1) UIA-N. The main change in body composition was an increase in water content in all ammonia-exposed fish. A significant increase in urea-N excretion rate was also observed over 0.33 mg.l(-1) UIA-N. Thresholds for growth were affected by exposure duration. Turbot juveniles growth capacity may be depressed by usual ambient ammonia concentrations under intensive farming conditions.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	http://archimer.ifremer.fr/doc/00188/29882/28354.pdf

DOI:10.1051/alr:1997034	
Editor: 	Gauthier-villars/editions Elsevier	
Relação: 	http://archimer.ifremer.fr/doc/00188/29882/	
Formato: 	application/pdf	
Fonte: 	Aquatic Living Resources (0990-7440) (Gauthier-villars/editions Elsevier), 1997-09 , Vol. 10 , N. 5 , P. 307-314	
Fonte: 	IFREMER-Elsevier, Paris