A comparison between water exchange and settling tank as a method for suspended solids management in intensive biofloc technology systems: effects on shrimp (Litopenaeus vannamei) performance,water quality and water use          下载免费PDF全文

Rafael Arantes  Rodrigo Schveitzer  Caio Magnotti  Katt Regina Lapa  Luis Vinatea 《Aquaculture Research》2017,48(4):1478-1490

Biofloc systems rely on microbial processes in the water column to recycle animal waste products, reducing the need for water exchange. These increases biofloc concentration in the water and some form of removal is needed. An experiment was carried out to evaluate two management practices to control biofloc in Litopenaeus vannamei culture. Six tanks (48 m³) were divided into two treatments: water exchange and solid settler. Shrimp were stocked at 164 shrimp m^?2 and with 0.67 g of weight. After 61 days, shrimp under solid settler treatment demonstrated mean weight of 12.7 ± 0.5 g with survival of 73.8 ± 1.4%, and those under water exchange had a final weight of 10.1 ± 0.2 g and survival rate of 57.8 ± 11.1%. Total suspended solids did not differ between the treatments: 326.8 ± 24.9 mg L^?1 for water exchange and 310.9 ± 25.3 mg L^?1 for solid settlers. Settleable solids and productivity/respiration ratio was higher (P < 0.05) in water exchange treatment, indicating differences in physical and biological characteristics of bioflocs. Solids removal method influenced the water use, in which 1150 ± 249 L of water was necessary to produce one kilogram of shrimp using water exchange strategy, and 631 ± 25 L kg^?1 with the use of settlers. Our results indicate that continuous operation of settlers can reduce variability in solids characteristics and water quality variables such as ammonia. Both strategies are efficient in controlling biofloc concentrations of the water; however, settlers can reduce water use and improve shrimp production.  相似文献   

Salt stress alters the morphoanatomy and primary and secondary metabolites of the leaves and rhizomes of Curcuma longa L.     

Bonacina  Cristine  Nascimento  Andressa Bezerra  Barbosa  Letícia Neris  de Souza  Silvia Graciele Hülse  Magalhães  Hélida Mara 《Journal of Crop Science and Biotechnology》2023,26(2):215-226

Journal of Crop Science and Biotechnology - During cultivation, environmental factors can cause changes in the metabolism of Curcuma longa L. that limit its development. This study evaluated the...  相似文献   

Effect of environmental factors on the fatty acid profiles and physicochemical composition of oysters (Crassostrea gasar) in Amazon estuarine farming     

Osnan Lennon Lameira Silva  Antnia Rafaela Gonalves Macedo  Emília do Socorro Conceio de Lima Nunes  Keila Diniz Campos  Leiliane Cristina Cardoso Araújo  Xenna Tiburo  Anne Suellen Oliveira Pinto  Maria Regina Sarkis Peixoto Joele  Micheli da Silva Ferreira  Ana Carolina Ramos da Silva  Renata Santana Lorenzo Raices  Adriano Gomes da Cruz  Leandro Juen  Rossineide Martins da Rocha 《Aquaculture Research》2020,51(6):2336-2348

The objective of this study was to evaluate the effect of environmental factors on the fatty acid profiles and physicochemical composition of Crassostrea gasar cultured in two locations with differences in salinity and precipitation gradients. The study period was divided into four seasonal divisions—the rainy–dry transition period, the dry season, dry–rainy transition and the rainy season. The salinity, pH and temperature were measured at each site during specimen collection. A total of 712 oyster samples were used for fatty acid profiling and physicochemical analysis. Salinity and precipitation were the environmental parameters that influenced the fatty acid profile and physicochemical characteristics of oysters. C. gasar exhibited excellent values of n3 polyunsaturated fatty acids (DHA, EPA and eicosatrienoic), with a predominance of these acids during periods of higher precipitation. Variations in precipitation and salinity resulted in significant differences in oyster nutritional characteristics. Oysters grown in Amazonian estuaries can be considered nutritious throughout the year, with better conditions during the rainy season.  相似文献   

A Study of the degradation in vitro of Organochlorine Compounds by the Meat Starter Micro-organism Micrococcus varians     

Susana Bayarri  Antonio Herrera  Agustín A. Ario  Regina Lzaro  Pilar Conchello 《Pest management science》1997,50(2):147-151

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