Egg incubation and larval rearing of piava, Leporinus obtusidens: effect of pH / Incubação de ovos e larvicultura da piava, Leporinus obtusidens: efeito do pH

The aim of this study was to evaluate the effect of the pH of the water during Leporinus obtusidens egg incubation and larval rearing. During incubation of the eggs pH 5.0, 7.0 and 9.0 were tested. pH 7.0 produced the best results for fertilization rate, hatching, and weight of hatched larvae (29.62 ± 6.01%, 23.57 ± 2.81% and 0.63 ± 0.01 mg, respectively). As pH 5.0 caused total mortality of eggs, the pH range was expanded in larval rearing that used pH 5.0, 6.0, 7.0, 8.0 and 9.0. pH 5.0 and 6.0 were lethal to the larvae at 24 and 72 h, respectively. At pH 9.0, higher survival (87.22 ± 3.47%) and final weight (3.82 ± 0.19 mg) were registered, whereas the final length of the larvae was the same (P>0.05) for pH 7.0, 8.0, and 9.0. Incubation at extreme pH values was harmful to the development of the L. obtusidens eggs, while at neutral pH (7.0), the best hatching rate and weight of hatched larvae were obtained. During larval rearing, the acidic pH was lethal to the larvae within just a few hours of exposure, whereas higher larvae survival and final weight were registered at pH 9.0.(AU)

O objetivo deste estudo foi avaliar o efeito do pH da água durante a incubação dos ovos e a larvicultura de Leporinus obtusidens. Durante a incubação dos ovos foram testados os pH 5,0, 7,0 e 9,0. Em pH 7,0 foram obtidas as maiores taxas de fertilização e de eclosão e o maior peso das larvas eclodidas (29,62 ± 6,01%, 23,57 ± 2,81% e 0,63 ± 0,01 mg, respectivamente). Como o pH 5,0 causou mortalidade total de ovos, a faixa de pH testada na larvicultura foi ampliada, tendo sido testados os pH 5,0, 6,0, 7,0, 8,0 e 9,0. Os pH 5,0 e 6,0 foram letais para as larvas em 24 e 72 h, respectivamente. Em pH 9,0 foram registrados os maiores valores de sobrevivência (87,22 ± 3,47%) e peso final (3,82 ± 0,19 mg), enquanto o comprimento final das larvas foi o mesmo (P>0,05) em pH 7,0, 8,0 e 9,0. A incubação em valores extremos de pH foi prejudicial ao desenvolvimento dos ovos de L. obtusidens, enquanto em pH neutro (7,0) foram obtidas as maiores taxas de eclosão e peso das larvas eclodidas. Durante a larvicultura, o pH ácido foi letal para as larvas após poucas horas de exposição, enquanto a maior sobrevivência e peso final foram registrados em pH 9,0.(AU)

Egg incubation and larval rearing of piava, Leporinus obtusidens: effect of pH / Incubação de ovos e larvicultura da piava, Leporinus obtusidens: efeito do pH

The aim of this study was to evaluate the effect of the pH of the water during Leporinus obtusidens egg incubation and larval rearing. During incubation of the eggs pH 5.0, 7.0 and 9.0 were tested. pH 7.0 produced the best results for fertilization rate, hatching, and weight of hatched larvae (29.62 ± 6.01%, 23.57 ± 2.81% and 0.63 ± 0.01 mg, respectively). As pH 5.0 caused total mortality of eggs, the pH range was expanded in larval rearing that used pH 5.0, 6.0, 7.0, 8.0 and 9.0. pH 5.0 and 6.0 were lethal to the larvae at 24 and 72 h, respectively. At pH 9.0, higher survival (87.22 ± 3.47%) and final weight (3.82 ± 0.19 mg) were registered, whereas the final length of the larvae was the same (P>0.05) for pH 7.0, 8.0, and 9.0. Incubation at extreme pH values was harmful to the development of the L. obtusidens eggs, while at neutral pH (7.0), the best hatching rate and weight of hatched larvae were obtained. During larval rearing, the acidic pH was lethal to the larvae within just a few hours of exposure, whereas higher larvae survival and final weight were registered at pH 9.0.

O objetivo deste estudo foi avaliar o efeito do pH da água durante a incubação dos ovos e a larvicultura de Leporinus obtusidens. Durante a incubação dos ovos foram testados os pH 5,0, 7,0 e 9,0. Em pH 7,0 foram obtidas as maiores taxas de fertilização e de eclosão e o maior peso das larvas eclodidas (29,62 ± 6,01%, 23,57 ± 2,81% e 0,63 ± 0,01 mg, respectivamente). Como o pH 5,0 causou mortalidade total de ovos, a faixa de pH testada na larvicultura foi ampliada, tendo sido testados os pH 5,0, 6,0, 7,0, 8,0 e 9,0. Os pH 5,0 e 6,0 foram letais para as larvas em 24 e 72 h, respectivamente. Em pH 9,0 foram registrados os maiores valores de sobrevivência (87,22 ± 3,47%) e peso final (3,82 ± 0,19 mg), enquanto o comprimento final das larvas foi o mesmo (P>0,05) em pH 7,0, 8,0 e 9,0. A incubação em valores extremos de pH foi prejudicial ao desenvolvimento dos ovos de L. obtusidens, enquanto em pH neutro (7,0) foram obtidas as maiores taxas de eclosão e peso das larvas eclodidas. Durante a larvicultura, o pH ácido foi letal para as larvas após poucas horas de exposição, enquanto a maior sobrevivência e peso final foram registrados em pH 9,0.

Dietary salt and water pH effects on growth and Na+ fluxes of silver catfish juveniles - doi: 10.4025/actascianimsci.v33i3.11192 / Dietary salt and water pH effects on growth and Na+ fluxes of silver catfish juveniles - doi: 10.4025/actascianimsci.v33i3.11192

This study verified the optimum dietary salt level for the growth and ion regulation of silver catfish juveniles at different water pH levels (5.5, 7.0 and 9.0). The control diet was supplemented with NaCl to yield experimental diets with 0.5, 1.0 and 2.0% NaCl. Juveniles were collected at 15 and 35 days after the beginning of experiment for analyses of Na+ net fluxes. Exposure of silver catfish juveniles to alkaline or acidic water did not affect their survival. Fish fed with diets without NaCl supplementation and exposed to pH 7.0 showed significantly higher weight, length, specific growth rate and biomass per tank than those exposed to pH 5.5. Ionoregulatory disturbances of silver catfish maintained at all pH are less pronounced when fed higher dietary salt supplementation (1.0-2.0% NaCl). The increase of dietary NaCl reduced body Na+ loss and protected against the impact of acidic water on growth.

This study verified the optimum dietary salt level for the growth and ion regulation of silver catfish juveniles at different water pH levels (5.5, 7.0 and 9.0). The control diet was supplemented with NaCl to yield experimental diets with 0.5, 1.0 and 2.0% NaCl. Juveniles were collected at 15 and 35 days after the beginning of experiment for analyses of Na+ net fluxes. Exposure of silver catfish juveniles to alkaline or acidic water did not affect their survival. Fish fed with diets without NaCl supplementation and exposed to pH 7.0 showed significantly higher weight, length, specific growth rate and biomass per tank than those exposed to pH 5.5. Ionoregulatory disturbances of silver catfish maintained at all pH are less pronounced when fed higher dietary salt supplementation (1.0-2.0% NaCl). The increase of dietary NaCl reduced body Na+ loss and protected against the impact of acidic water on growth.

Dietary salt and water pH effects on growth and Na+ fluxes of silver catfish juveniles / Efeito do sal na dieta e do pH da água no crescimento de juvenis de jundiá

This study verified the optimum dietary salt level for the growth and ion regulation of silver catfish juveniles at different water pH levels (5.5, 7.0 and 9.0). The control diet was supplemented with NaCl to yield experimental diets with 0.5, 1.0 and 2.0% NaCl. Juveniles were collected at 15 and 35 days after the beginning of experiment for analyses of Na+ net fluxes. Exposure of silver catfish juveniles to alkaline or acidic water did not affect their survival. Fish fed with diets without NaCl supplementation and exposed to pH 7.0 showed significantly higher weight, length, specific growth rate and biomass per tank than those exposed to pH 5.5. Ionoregulatory disturbances of silver catfish maintained at all pH are less pronounced when fed higher dietary salt supplementation (1.0-2.0% NaCl). The increase of dietary NaCl reduced body Na+ loss and protected against the impact of acidic water on growth.

Este estudo verificou o melhor nível de dieta de sal para o crescimento e regulação iônica de juvenis de jundiá em diferentes níveis de pH da água (5,5; 7,0 e 9,0). A dieta controle foi suplementada com 0,5; 1,0 e 2,0% de NaCl. Juvenis foram coletados aos 15 e 35 dias de experimento para análise dos fluxos líquidos de Na+. A exposição de juvenis de jundiá para águas ácidas ou alcalinas não afetou sua sobrevivência. Exemplares alimentados com dietas sem adição de NaCl e expostos em pH 7,0 mostraram peso, comprimento, taxa de crescimento específico e biomassa/tanque significativamente maiores que aqueles expostos em pH 5,5. Distúrbios ionorregulatórios em jundiás mantidos em todos os pH são menos pronunciados quando em exemplares alimentados com dietas com maior suplmentação de sal (1,0-2,0% NaCl). O aumento de NaCl na dieta reduziu a perda de Na+ corporal e protegeu contra o impacto da acidez da água no crescimento dos juvenis.

Low water hardness and pH affect growth and survival of silver catfish juveniles

The objective of this study was to investigate the effects of exposure to low water hardness (0, 25 and 50mg CaCO3L-1) into the 6.0-8.0 pH range to silver catfish juveniles (Rhamdia quelen) survival and growth after 32 days. Juveniles kept at zero water hardness presented higher mortality at pH 7.0 and 8.0 than those submitted to other treatments. Weight of juveniles exposed to pH 6.0 and zero water hardness was significantly higher than those kept at the same water hardness and other pH. Survival and growth of juveniles exposed to 25 and 50mg CaCO3 L-1 was not affected in the 6.0-8.0 pH range. Therefore, the best water hardness for silver catfish juveniles growth is 25-50mg CaCO3 L-1 and at low water hardness (next zero) pH must be reduced.

O objetivo deste estudo foi investigar os efeitos da exposição em baixas durezas da água (0; 25 e 50mg CaCO3 L-1) na faixa de pH 6,0-8,0 no crescimento e na sobrevivência de juvenis de jundiás (Rhamdia quelen). Os juvenis foram expostos aos tratamentos durante 32 dias. Os indivíduos mantidos em dureza zero da água apresentaram maior mortalidade em pH 7,0 e 8,0 do que aqueles submetidos aos outros tratamentos. O peso dos juvenis expostos ao pH 6,0 com zero dureza da água foram significativamente maiores do que aqueles mantidos na mesma dureza e em outras faixas de pH. A sobrevivência e o crescimento dos indivíduos expostos em 25 e 50mg CaCO3L-1 não foi afetado na faixa de pH 6,0-8,0. Portanto, a melhor dureza da água para o crescimento e de juvenis de jundiá é 25-50mg CaCO3 L-1 e em baixa dureza da água (próxima a zero) o pH deve ser reduzido.

Low water hardness and pH affect growth and survival of silver catfish juveniles

The objective of this study was to investigate the effects of exposure to low water hardness (0, 25 and 50mg CaCO3L-1) into the 6.0-8.0 pH range to silver catfish juveniles (Rhamdia quelen) survival and growth after 32 days. Juveniles kept at zero water hardness presented higher mortality at pH 7.0 and 8.0 than those submitted to other treatments. Weight of juveniles exposed to pH 6.0 and zero water hardness was significantly higher than those kept at the same water hardness and other pH. Survival and growth of juveniles exposed to 25 and 50mg CaCO3 L-1 was not affected in the 6.0-8.0 pH range. Therefore, the best water hardness for silver catfish juveniles growth is 25-50mg CaCO3 L-1 and at low water hardness (next zero) pH must be reduced.

O objetivo deste estudo foi investigar os efeitos da exposição em baixas durezas da água (0; 25 e 50mg CaCO3 L-1) na faixa de pH 6,0-8,0 no crescimento e na sobrevivência de juvenis de jundiás (Rhamdia quelen). Os juvenis foram expostos aos tratamentos durante 32 dias. Os indivíduos mantidos em dureza zero da água apresentaram maior mortalidade em pH 7,0 e 8,0 do que aqueles submetidos aos outros tratamentos. O peso dos juvenis expostos ao pH 6,0 com zero dureza da água foram significativamente maiores do que aqueles mantidos na mesma dureza e em outras faixas de pH. A sobrevivência e o crescimento dos indivíduos expostos em 25 e 50mg CaCO3L-1 não foi afetado na faixa de pH 6,0-8,0. Portanto, a melhor dureza da água para o crescimento e de juvenis de jundiá é 25-50mg CaCO3 L-1 e em baixa dureza da água (próxima a zero) o pH deve ser reduzido.

Low water hardness and pH affect growth and survival of silver catfish juveniles

The objective of this study was to investigate the effects of exposure to low water hardness (0, 25 and 50mg CaCO3L-1) into the 6.0-8.0 pH range to silver catfish juveniles (Rhamdia quelen) survival and growth after 32 days. Juveniles kept at zero water hardness presented higher mortality at pH 7.0 and 8.0 than those submitted to other treatments. Weight of juveniles exposed to pH 6.0 and zero water hardness was significantly higher than those kept at the same water hardness and other pH. Survival and growth of juveniles exposed to 25 and 50mg CaCO3 L-1 was not affected in the 6.0-8.0 pH range. Therefore, the best water hardness for silver catfish juveniles growth is 25-50mg CaCO3 L-1 and at low water hardness (next zero) pH must be reduced.

O objetivo deste estudo foi investigar os efeitos da exposição em baixas durezas da água (0; 25 e 50mg CaCO3 L-1) na faixa de pH 6,0-8,0 no crescimento e na sobrevivência de juvenis de jundiás (Rhamdia quelen). Os juvenis foram expostos aos tratamentos durante 32 dias. Os indivíduos mantidos em dureza zero da água apresentaram maior mortalidade em pH 7,0 e 8,0 do que aqueles submetidos aos outros tratamentos. O peso dos juvenis expostos ao pH 6,0 com zero dureza da água foram significativamente maiores do que aqueles mantidos na mesma dureza e em outras faixas de pH. A sobrevivência e o crescimento dos indivíduos expostos em 25 e 50mg CaCO3L-1 não foi afetado na faixa de pH 6,0-8,0. Portanto, a melhor dureza da água para o crescimento e de juvenis de jundiá é 25-50mg CaCO3 L-1 e em baixa dureza da água (próxima a zero) o pH deve ser reduzido.

Dietary salt and water pH effects on growth and Na+ fluxes of silver catfish juveniles - doi: 10.4025/actascianimsci.v33i3.11192 / Dietary salt and water pH effects on growth and Na+ fluxes of silver catfish juveniles - doi: 10.4025/actascianimsci.v33i3.11192

This study verified the optimum dietary salt level for the growth and ion regulation of silver catfish juveniles at different water pH levels (5.5, 7.0 and 9.0). The control diet was supplemented with NaCl to yield experimental diets with 0.5, 1.0 and 2.0% NaCl. Juveniles were collected at 15 and 35 days after the beginning of experiment for analyses of Na+ net fluxes. Exposure of silver catfish juveniles to alkaline or acidic water did not affect their survival. Fish fed with diets without NaCl supplementation and exposed to pH 7.0 showed significantly higher weight, length, specific growth rate and biomass per tank than those exposed to pH 5.5. Ionoregulatory disturbances of silver catfish maintained at all pH are less pronounced when fed higher dietary salt supplementation (1.0-2.0% NaCl). The increase of dietary NaCl reduced body Na+ loss and protected against the impact of acidic water on growth.

This study verified the optimum dietary salt level for the growth and ion regulation of silver catfish juveniles at different water pH levels (5.5, 7.0 and 9.0). The control diet was supplemented with NaCl to yield experimental diets with 0.5, 1.0 and 2.0% NaCl. Juveniles were collected at 15 and 35 days after the beginning of experiment for analyses of Na+ net fluxes. Exposure of silver catfish juveniles to alkaline or acidic water did not affect their survival. Fish fed with diets without NaCl supplementation and exposed to pH 7.0 showed significantly higher weight, length, specific growth rate and biomass per tank than those exposed to pH 5.5. Ionoregulatory disturbances of silver catfish maintained at all pH are less pronounced when fed higher dietary salt supplementation (1.0-2.0% NaCl). The increase of dietary NaCl reduced body Na+ loss and protected against the impact of acidic water on growth.