Jaqueline Ineu Golombieski

Transport of silver catfish (Rhamdia quelen) fingerlings at different times, load densities, and temperatures

Abstract Silver catfish (Rhamdia quelen) fingerlings (5–10 cm) were caught from a fish culture pond and placed in a tank for stomach emptying for 24 h. Fingerlings were then weighed and placed in plastic bags (5 l) with 1.5 l water and oxygen, which were kept at temperatures of 15, 20, and 25 °C. The load densities tested were 50, 67, 87, and 168 g l−1. When bags were opened after 6, 12, or 24 h, mortality, dissolved oxygen, pH, total ammonia, non-ionized ammonia, total hardness, nitrite, total alkalinity, and carbon dioxide levels were determined. There was fingerling mortality only at the load density of 168 g l−1 after 24 h of transport at 20 and 25 °C, suggesting that mortality increased with temperature and time of transport. The dissolved oxygen levels in the water were reduced throughout 24 h of transport in the load density of 168 g l−1 at 20 and 25 °C, but remained unchanged at the other load densities. The pH decreased significantly at all load densities and temperatures throughout 24 h. Total alkalinity, total ammonia, and carbon dioxide levels increased significantly up to 24 h of transport in all treatments. Non-ionized ammonia and nitrite levels were below 0.02 and 0.06 mg l−1, respectively. Total hardness ranged from 20 to 48 mg l−1 CaCO3. The best temperature for transporting fingerlings of this species in plastic bags is 15 °C, because up to 24 h there was no significant mortality even at the load density of 168 g l−1, dissolved oxygen levels were still high, and total ammonia and carbon dioxide presented the lowest increase. Transport at 25 °C and a load density of 168 g l−1 must not exceed 6 h due to the high levels of ammonia and carbon dioxide and low dissolved oxygen levels in the water.

Incubation of silver catfish, Rhamdia quelen (Pimelodidae), eggs at different calcium and magnesium concentrations

Abstract Ca 2+ and Mg 2+ are important for ionic regulation of freshwater fish because both ions influence the permeability of biological membranes, preventing diffusive flow and high ionic loss to water. The objective of this study was to analyze the hatchery rate and post-hatch survival of silver catfish ( Rhamdia quelen ) eggs at different Ca 2+ and Mg 2+ concentrations. Eggs were incubated in continuously aerated 4-l polyethylene bottles (600 eggs/bottle) at 24 °C and randomly divided into five treatments (three replicates per treatment) with different concentrations of Ca 2+ and Mg 2+ at hardness values of 70 and 150 mg l −1 CaCO 3 . There were also two control groups with hardness of values 20 mg l −1 CaCO 3 . Dissolved oxygen, pH, temperature, total alkalinity and nonionized ammonia levels in water were always satisfactory for fish culture throughout the experiments. The increase of water hardness to 70 mg l −1 CaCO 3 (all treatments) increased hatch rate, but the highest Ca 2+ level reduced post-hatch survival. However, the eggs incubated at water hardness of 150 mg l −1 CaCO 3 presented the lowest hatch rates and post-hatch survival values at higher Ca 2+ concentrations. These results suggest that the increase of water hardness to 70 mg l −1 CaCO 3 using either Ca 2+ or Mg 2+ improved hatch rate, but the increase of waterborne Ca +2 above 20 mg l −1 , irrespective of water hardness, is not indicated for incubation of silver catfish eggs because it reduces post-hatch survival.

Efficacy of Different Salt (NaCl) Concentrations in the Treatment of Ichthyophthirius multifiliis-Infected Silver Catfish, Rhamdia quelen, Fingerlings

ABSTRACT The objective of this study was to evaluate different salt concentrations in the treatment of Ichthyophthirius multifiliis. Silver catfish, Rhamdia quelen, fingerlings infected with I. multifiliis were submitted to four sodium chloride concentrations (g/L): 0,1,2, and 4 for 23 days. In a second experiment, fingerlings were maintained with 4 g/L salt, but for 45 days. Treatments with 2 and 4 g/L salt significantly increased fingerling survival compared with 0 and 1 g/L, and survival was significantly correlated with salt concentrations. In the second experiment, fish maintained at 4 g/L salt showed a gradual reduction of “white spots” and survival was 100%. Therefore, salt offers an alternative for treatment of silver catfish fingerlings infected with I. multifiliis.

Acetylcholinesterase enzyme activity in carp brain and muscle after acute exposure to diafuran

Exposicao a inseticidas em concentracoes elevadas no ambiente podem ocasionar efeitos adversos subletais em organismos aquaticos. Alevinos de carpa hungara (Cyprinus carpio, Linnaeus, 1758), carpa capim (Ctenopharyngodon idella, Valenciennes, 1844) e carpa cabeca grande (Aristichthys nobilis, Richardson, 1845) foram expostos ao diafuran, um inseticida utilizado na cultura do arroz no sul do Brasil. O objetivo deste estudo foi verificar a relacao entre concentracao letal mediana (CL50) do diafuran e a atividade da enzima acetilcolinesterase (AChE) em cerebro e musculo dessas especies, como um possivel biomarcador inicial da exposicao a este inseticida. A CL50 foi determinada com peixes expostos a concentracoes de diafuran em 96 h: carpa hungara: controle; 0,5; 1,0; 1,5; 2,0; 2,5 e 3,0 mg L-1; carpa capim: controle; 1,0; 2,0; 3,0 e 3,5 mg L-1 e carpa cabeca grande: controle; 0,5; 1,0; 1,5; 2,0; 3,0 e 4,0 mg L-1, bem como a determinacao da AChE em concentracoes proximas da CL50 para essas especies. Valores de CL50 (concentracoes nominais) foram de 1,81 mg L-1 para carpa hungara, 2,71 mg L-1 para carpa capim e 2,37 mg L-1 para carpa cabeca grande. Todas as carpas expostas ao diafuran estavam letargicas (menores concentracoes) ou imoveis. Diafuran inibiu significativamente a atividade da AChE em cerebro (~38 %) e musculo (~50 %) de todas as especies estudadas. Atividade da AChE em musculo para carpa cabeca grande foi mais alta que cerebro (14,44 contra 5,94 µmol min-1 g proteina-1, respectivamente). Este estudo demonstrou que concentracoes de diafuran utilizadas na cultura do arroz podem afetar o comportamento de Cyprinus carpio, Ctenopharyngodon idella e Aristichthys nobilis, e a atividade da acetilcolinesterase cerebral e muscular pode ser um biomarcador inicial de toxicidade deste inseticida.Exposicao a inseticidas em concentracoes elevadas no ambiente podem ocasionar efeitos adversos subletais em organismos aquaticos. Alevinos de carpa hungara (Cyprinus carpio, Linnaeus, 1758), carpa capim (Ctenopharyngodon idella, Valenciennes, 1844) e carpa cabeca grande (Aristichthys nobilis, Richardson, 1845) foram expostos ao diafuran, um inseticida utilizado na cultura do arroz no sul do Brasil. O objetivo deste estudo foi verificar a relacao entre concentracao letal mediana (CL50) do diafuran e a atividade da enzima acetilcolinesterase (AChE) em cerebro e musculo dessas especies, como um possivel biomarcador inicial da exposicao a este inseticida. A CL50 foi determinada com peixes expostos a concentracoes de diafuran em 96 h: carpa hungara: controle; 0,5; 1,0; 1,5; 2,0; 2,5 e 3,0 mg L-1; carpa capim: controle; 1,0; 2,0; 3,0 e 3,5 mg L-1 e carpa cabeca grande: controle; 0,5; 1,0; 1,5; 2,0; 3,0 e 4,0 mg L-1, bem como a determinacao da AChE em concentracoes proximas da CL50 para essas especies. Valores de CL50 (concentracoes nominais) foram de 1,81 mg L-1 para carpa hungara, 2,71 mg L-1 para carpa capim e 2,37 mg L-1 para carpa cabeca grande. Todas as carpas expostas ao diafuran estavam letargicas (menores concentracoes) ou imoveis. Diafuran inibiu significativamente a atividade da AChE em cerebro (~38 %) e musculo (~50 %) de todas as especies estudadas. Atividade da AChE em musculo para carpa cabeca grande foi mais alta que cerebro (14,44 contra 5,94 µmol min-1 g proteina-1, respectivamente). Este estudo demonstrou que concentracoes de diafuran utilizadas na cultura do arroz podem afetar o comportamento de Cyprinus carpio, Ctenopharyngodon idella e Aristichthys nobilis, e a atividade da acetilcolinesterase cerebral e muscular pode ser um biomarcador inicial de toxicidade deste inseticida.

Hypoxia acclimation protects against oxidative damage and changes in prolactin and somatolactin expression in silver catfish (Rhamdia quelen) exposed to manganese

The aim of this study was to assess the Mn toxicity to silver catfish considering Mn accumulation and oxidative status in different tissues, as well as pituitary hormone expression after acclimation to hypoxia. Silver catfish acclimated to hypoxia for 10 days and successively exposed to Mn (9.8 mg L(-1)) for an additional 10 days exhibited lower Mn accumulation in plasma, liver, kidneys and brain and prevented the hematocrit decrease observed in the normoxia group. Hypoxia acclimation also modified Mn-induced oxidative damage, which was observed by lower reactive species (RS) generation in gills and kidneys, decreased lipid peroxidation (LP) levels in gills, liver and kidneys and decreased protein carbonyl (PC) levels in liver, kidneys and brain. Manganese accumulation showed positive correlations with LP levels in gills and kidneys, as well as with PC levels in gills, liver and brain. In addition, hypoxia acclimation and Mn exposure increased catalase (CAT) activity in gills and kidneys and Na(+)/K(+)-ATPase activity in gills, liver and brain. Silver catfish that were acclimated under normoxia and exposed to Mn displayed increased pituitary prolactin (PRL) and decreased somatolactin (SL) expression. Interestingly, hypoxia acclimation prevented hormonal fluctuation of PRL and SL in fish exposed to Mn. These findings indicate that while the exposure of silver catfish to Mn under normoxia was related to metal accumulation and oxidative damage in tissues together with endocrine axis disruption, as represented by PRL and SL, hypoxia acclimation reduced waterborne Mn uptake, thereby minimizing oxidative damage and changes in hormonal profile. We hypothesized that moderate hypoxia is able to generate adaptive responses, which may be related to hormesis, thereby ameliorating Mn toxicity to silver catfish.

Alterations in fatty acid composition due to cold exposure at the vegetative stage in rice.

Rice is a tropical plant, so cold temperature may be detrimental to its development, depending on the genotype and environmental conditions. Degree of lipid unsaturation has been related to cold tolerance due to its effect on membrane stability. So, the aim of this study was to characterize the fatty acid composition and its alterations due to cold temperature in rice genotypes of diversified origin. Forty-four rice genotypes at the V4 stage were submitted to two temperature conditions: 10°C and 28°C for two days and after this they had their leaves collected for lipid extraction and quantification. Control plants were allowed to regrow until presenting four leaves fully expanded and then were subjected to 10°C for ten days for cold tolerance evaluation. Plant survival was measured seven days after recovery at 28°C and the genotypes were grouped in three cold tolerance classes: tolerant, intermediate and sensitive. These classes differed for total saturated and unsaturated fatty acids only under the cold temperature treatment. Further analysis of the more abundant fatty acids: linoleic, linolenic and palmitic, showed that the two last ones differed between tolerant and sensitive genotypes. Linolenic acid increased after cold exposure in cold tolerant genotypes while palmitic acid decreased, and an opposite behavior was found in the cold sensitive genotypes. These evidences indicate that these fatty acids are potential molecular markers useful for breeding programs as well as for future basic studies on cold tolerance in rice.

Growth and survival of silver catfish larvae, Rhamdia quelen (Heptapteridae), at different calcium and magnesium concentrations

Since the relative ratios of Ca2+ and Mg2+ can vary greatly from one water body to another, and lime used for the increase of water hardness or pH can have different ratios of Ca2+ and Mg2+ in its composition, the objective of this study was to analyze the growth and survival of silver catfish, Rhamdia quelen, larvae at different calcium and magnesium concentrations. After fertilization, eggs were randomly divided into 4 treatments (three replicates per treatment) with different concentrations of Ca2+ and Mg2+ at hardness values of 70 mg.L-1 CaCO3 (mg.L-1 : 5.2 Ca2+ and 14.12 Mg2+; 13.11 Ca2+ and 7.11 Mg2+; 20.26 Ca2+ and 2.86 Mg2+; 24.95 Ca2+ and 0.95 Mg2+) and 150 mg.L-1 CaCO3 (mg.L-1 : 5.2 Ca2+ and 32.70 Mg2+; 28.63 Ca2+ and 16.44 Mg2+; 44.68 Ca2+and 6.44 Mg2+; 62.78 Ca2+ and 0.95 Mg2+). There was also another group exposed to water hardness of 20 mg.L-1 CaCO3 (Ca2+ 5.2 mg.L-1 and Mg2+ 0.95 mg.L-1) at both experiments. The post-hatch larvae were transferred to continuously aerated 40 L polyethylene aquaria (400 larvae/tank) containing the same water as used for incubation. Samples of larvae were collected on days 0, 7, 14, and 21, and the length, weight, and specific growth rate were determined for each collection. Survival and biomass were calculated on day 21. At water hardness of 70 mg.L-1 CaCO3, the best survival and growth of silver catfish larvae was observed at water with 20.26 mg.L-1 Ca2+ and 2.89 mg.L-1 Mg2+, with similar results to the group exposed to water hardness of 20 mg.L-1 CaCO3. However, compared to the group exposed to water hardness of 20 mg.L-1 CaCO3, survival and growth were lower at 150 mg.L-1 CaCO3. Therefore, a hardness range of 20 to 70 mg.L-1 CaCO3 is recommended for silver catfish larviculture, but with 20.26 mg.L-1 Ca2+ and 2.89 mg.L-1 Mg2+ at 70 mg.L-1 CaCO3. Water hardness of 150 mg.L-1 CaCO3 is not recommended for this species.

Qualidade da água no consórcio de peixes com arroz irrigado

The goal of the present work was to evaluate quality parameters of the water utilized in combination of the fish culture with irrigate rice. The experiment was carried in low land area, with rice pre-germinate system associated with farming of carps and silver catfish, where the levels of dissolved oxygen, temperature, pH, hardness, total alkalinity, ammonia, nitrite and water transparency were weekly monitored. The physical-chemical characteristics of the water (temperature, pH, hardness, total alkalinity, ammonia, and nitrite) do not affect the growth and development of the fish in combination with irrigate rice for cultived species (60% commom carp, 20% grass carp, 10% silver catfish, 5% silver carp and 5% bighead carp) Although, the quantities of fish utilized and time of entry fingerlings affect certain water quality parameters (dissolved oxygen and water transparency) in general they maintain in levels adequate to with the standard for these species.

Lethal concentration of clomazone, metsulfuron-metil, and quinclorac for silver catfish, Rhamdia quelen, fingerlings

The goal of the present work was to determine the lethal concentration (LC50) (96h) of clomazone, metsulfuron-methyl, and quinclorac, herbicides used in rice culture, for the silver catfish, Rhamdia quelen. Fingerlings were exposed to different concentrations of the herbicides. The LC50s were 7.32µL L-1 for clomazone and 395mg L-1 for quinclorac. The LC50 for metsulfuron-methyl was not obtained since all fingerlings survived even at 1200mgL-1. Probably only clomazone can lead to mortality among silver catfish reared in the rice culture system.

Cladocers, Copepods and Rotifers in rice-fish culture handled with metsulfuron-methyl and azimsulfuron herbicides and carbofuran insecticide

O presente estudo determinou o efeito de metsulfuron-metilico, azimsulfuron e carbofuran nas comunidades: Cladocera, Copepoda e Rotifera presentes em lavouras de arroz irrigado com o sistema de rizipiscicultura. O experimento foi conduzido durante a safra agricola 2004/05 com oito tratamentos. As especies de peixes utilizadas foram: Cyprinus carpio, Ctenopharyngodon idella e Aristichthys nobilis, introduzidas sete dias apos a aplicacao dos tratamentos. Amostras de agua foram coletadas 17 dias antes e no(s) 1°, 3°, 10°, 18°, 31°, 51° e 75° dias apos a aplicacao dos tratamentos para a identificacao e a avaliacao de zooplâncton. Os resultados indicam que os herbicidas estudados nao afetaram a comunidade zooplanctonica e a aplicacao do inseticida carbofuran provocou efeitos negativos em Cladocera. Copepoda e Rotifera foram pouco afetados pelo carbofuran.