Aims Aeromonas hydrophila is an opportunistic bacterium, with a high capacity for biofilm production, which can cause severe damage in aquaculture. The objective of this study was to identify the chemical compounds of the essential oils of Lippia sidoides (EOLS) and Cymbopogon citratus (EOCC), and to evaluate the biocidal, antibiofilm and synergistic action with the antimicrobial florfenicol of these essential oils (EOs) against A. hydrophila. Methods and Results The antibacterial activity of EOLS and EOCC was verified by the minimum bactericidal concentration and by the action of these EOs against both forming and consolidated biofilms. The synergistic activity of EOs with florfenicol was performed using the checkerboard technique. The main component of EOLS and EOCC was carvacrol (44.50%) and α‐citral (73.56%), respectively. Both EOs showed weak inhibitory activity (≥3125.00 µg ml−1). Two bacterial isolates were able to produce biofilm, and EOLS and EOCC acted upon the bacterial isolates to prevent biofilm formation. A bactericidal effect was verified for EOLS in the previously consolidated biofilm for both isolates and for EOCC in only one of the isolates. In general, EOLS had a synergistic effect with florfenicol, while EOCF had an additive effect. Conclusions Both EOs were able to interfere with biofilm formation and did not have an antagonistic effect in combination with florfenicol. The best results were found for EOLS, which showed a synergistic effect with florfenicol and the ability to interfere in the formation of consolidated biofilm. Significance and Impact of the Study This study highlights the potential of EOLS and EOCC to interfere in biofilm and act in synergy with florfenicol to reduce the occurrence of A. hydrophila. Development of these compounds may contribute to the development of herbal medicines in aquaculture.

No abstract

No abstract

No abstract

ResumoAs lemnaceas são plantas aquáticas com grande potencial de uso como matéria prima para ração de peixes devido ao alto valor nutricional. O objetivo deste estudo foi avaliar a composição química e a qualidade nutricional de Lemna valdiviana submetida a diferentes concentrações de adubação com excremento de aves. O experimento foi realizado em delineamento inteiramente casualizado com três repetições. Os tratamentos foram: Controle (sem adubação); T1 -150g.m -3 , T2 -300g.m -3 e T3 -450 g.m -3 de excremento de aves fresco, distribuídos em dose única para fertilizar o cultivo de L. valdiviana. A dose que proporcionou a melhor qualidade nutricional de L. valdiviana foi 450g.m -3 de excremento de aves, com teor de proteína bruta de 19,66% na matéria seca, percentual de fibras de 13,06% e teor de 0,26% de P, 1, 63% de N, 0,37% de Na e 1,22% de Ca na massa seca. Os teores alcançados nesse estudo indicam a possibilidade da L. valdiviana ser considerada uma matéria prima de boa qualidade nutricional para ser utilizada em outros experimentos como complemento na ração para peixes. Unitermos: ração, valor nutricional, caracterização química, lemnas AbstractNutritional value of Lemna valdiviana Phil (Araceae) submitted to different concentrations of fertilization with excrement of birds. The lemnaceas are aquatic plants with great potential for use as raw material in the production of fish feed because they have a high nutritional value. The objective of this study was to evaluate the chemical composition and nutritional quality of Lemna valdiviana submitted to different

The objective of this research was to evaluate the effect of desensitisation by electronarcosis on the changes to the fatty acid profile of cobia (Rachycentron canadum) fillets stored at low sub-zero temperature. For stunning, 50, 100 and 150 V were used for 120 s and then exsanguination was performed, followed by storage at í 18 °C for 180 days. A total of 47 fatty acids were detected in cobia fillet samples, and most of the quantified fatty acids differed (p < 0.05) between treatments and storage times. The n6/n3 ratio did not differ (p > 0.05) among treatments; however, the n6/n3 ratio and Σhypocholesterolaemic fatty acids Æ©hypercholesterolaemic fatty acids ratio were significantly affected by the storage times and their outcomes. In general, the electronarcosis intensities used to numb cobia did not promote differences during the frozen storage of the fillets for most of the analysed variables but a significant effect of the storage time was noted within the treatments, with meat quality loss observed over time.

The effect on tambaqui fingerlings performance caused by diets containing two different carbohydrate sources was evaluated. Four isoproteic diets with different mango meal concentrations (0, 33, 66 and 100%) replacing cornmeal were tested. The feeding trial lasted 45 days and the feeding rate was 8% of total biomass. 240 tambaqui fingerlings with an initial weight average of 3.66g were distributed in 12 500-liter tanks in a recirculating water system with biofilter. Performance, feed intake, carcass yield, survival, total cholesterol, plasmatic free amino acids, hepatic aspartate aminotransferase(AST), hepatic glycogen and plasma glucose values were evaluated. The results showed that weight gain, daily weight gain, specific growth rate, apparent food consumption, cholesterol, AST and glycogen showed higher values in the treatments with the highest levels of mango meal. Apparent feed conversion, carcass yield, survival and plasma glucose were not affected by the two sources of carbohydrates tested. In conclusion, mango meal used in a practical diet for tambaqui improved growth performance.

The objective of this study was to evaluate the effect of pure glucose, glucose plus fructose, and fructose on the blood glucose of omnivorous fi sh tambaqui (Colossoma macropomum), Nile tilapia (Oreochromis niloticus), piau (Leporinus elongatus), and carnivorous fi sh hybrid Amazon catfi sh (Pseudoplatystoma fasciatum × Leiarius marmoratus), pacamã (Lophiosilurus alexandri), and traíra (Hoplias malabaricus). In each species, the dose 1 mL per fi sh with 1,000 mg kg of body weight -1 of glucose, fructose or glucose plus fructose were tested intraperitoneally. Blood glucose was measured at times 0 (control), 0.5, 1, 2, 4, 8, 16, and 24 h. The administration of 1,000 mg of glucose or glucose plus fructose per kg of live weight causes hyperglycemia in the omnivorous and carnivorous species studied. In the omnivorous species, glycemic levels were reduced from 2 to 4 h, and the regulation to baseline occurred from 4 to 8 h. In the carnivores fi sh, blood glucose levels declined between 1 and 8 h, and return to baseline was observed from 8 to 16 h. Tambaqui was also intolerant to high concentrations of fructose. Blood glucose levels are regulated in a shorter time in Nile tilapia (mainly), piau and pacamã.