RESUMO
The effects of dietary digestible protein (DP) levels (22, 26, 29, 32, and 34%) and different stressors (cold-induced stress, CIS; heat/dissolved oxygen-induced stress, HDOIS; transport-induced stress, TIS; and size-sorting-induced stress, SSIS) on hemato-biochemical parameters were evaluated. Four hundred and forty Nile tilapia fingerlings were distributed into 40-250 L aquaria and fed experimental diets for 110 days, and fed each of the five experimental diets, that were randomly distributed to eight replicates per treatment. Then, different groups of fish were subjected to one type of stress. Groups of 40 fish were used on CIS (17 °C), HDOIS (32 °C), and TIS (4 h), and a group of 140 fish on SSIS (15 min air exposure and 60 s handling). There was no effect on hemato-biochemical profile when DP levels were compared, neither before nor after stress; however, there was a significant stress effect. Digestible protein did not mitigate stress response under SSIS and CIS; lymphopenia and neutrophilia were the main cell-mediated immune response; dietary 22 and 26% DP impaired oxygenation on SSIS and TIS; fish under HDOIS and SSIS demanded more energy using triglycerides as an energy source; the diet formulated to contain 22% DP was not adequate to keep homeostasis under temperature stress. Cluster analysis showed that, for DP levels below the requirement for growth, SSIS and CIS were considered the most stressful conditions. At 34% DP level, HDOIS response was comparable to that of non-stressing conditions.(AU)
Assuntos
Animais , Biossíntese de Proteínas , Resposta ao Choque Térmico/fisiologia , Ciclídeos/fisiologiaRESUMO
We evaluated the economic responses of Nile tilapia in the final stage (450 to 800 g) fed diets containing five levels of digestible protein (DP): 20, 23, 26, 29 and 32% and two digestible energy levels (DE): 3,000 and 3,300 kcal kg-1 based on the sale of whole animals or fillet. This experiment was carried out into 50 m3 net cages in an aquaculture area located in Paranapanema River, Palmital - São Paulo State, Brazil, from November 21st, 2010 to January 21st. Economic performance indicators were: gross revenue, partial production cost, net revenue, leveling point, balance point, benefit cost ratio and cost of feed kg-1 gain. Twenty-nine percent of DP and 3,000 kcal DE kg-1 diet provided better economic performance for sale of whole fish, meaning higher net revenue (R$ 23.09 net cage-1) and benefit cost ratio (1.08), besides the lowest balance point (R$ 3.91 kg-1). Thirty-two percent of DP and 3,000 kcal DE kg-1 diet provided the lowest cost of feed kg-1 (R$ 2.53), leveling point (17.35 kg net cage-1) and balance point (R$ 13.63 kg-1), besides the highest benefit cost ratio (1.54) when the fish were sold in fillet form. Diets with 29% and diet with 32% digestible protein, both of them with 3,000 kcal of digestible energy kg-1 diet provides better economic responses in Nile tilapia reared in net cages (450 to 800 g), to be sold, respectively, whole or fillets form.
Avaliaram-se as respostas econômicas da produção de tilápia-do-nilo na fase de terminação (450 a 800 g), alimentadas com dietas contendo cinco níveis de proteína digestível (PD): 20, 23, 26, 29 e 32% e dois de energia digestível (ED): 3.000 e 3.300 kcal kg-1 de dieta, com base na venda de animais inteiros ou filés. A pesquisa foi conduzida em 50 tanques-rede (1 m3), em área aquícola localizada no rio Paranapanema, Palmital-SP, Brasil, de 21 de novembro de 2010 à 21 de janeiro de 2011. Os indicadores de desempenho econômico calculados foram: receita bruta, custo de produção parcial, receita líquida, ponto de nivelamento, ponto de equilíbrio, relação benefício custo e custo da ração kg-1. A dieta contendo 29% de PD e 3.000 kcal de ED kg-1 proporcionou melhor desempenho econômico para venda de peixes inteiros, ou seja, maior receita líquida (R$ 23,09 tanque-rede-1) e relação benefício custo (1,08), além do menor ponto de equilíbrio (R$ 3,91 kg-1). A dieta com 32% de PD e 3.000 kcal de ED kg-1 possibilitou para a venda de filés o menor custo da ração kg-1 (R$ 2,53), menor ponto de nivelamento (17,35 kg tanque-rede-1) e de equilíbrio (R$ 13,63 kg-1), além da mais alta relação benefício custo (1,54). A dieta contendo 29% e a dieta contendo 32% de proteína digestível, ambas com 3.000 kcal de energia digestível kg-1 proporcionam melhores respostas econômicas de tilápias-do-nilo recriadas em tanques-rede (450 a 800 g), ao serem vendidas, respectivamente, inteiras e na forma de filés.
Assuntos
Animais , Ciclídeos , Custos e Análise de Custo , Proteínas Alimentares , Ração Animal/economiaRESUMO
We evaluated the economic responses of Nile tilapia in the final stage (450 to 800 g) fed diets containing five levels of digestible protein (DP): 20, 23, 26, 29 and 32% and two digestible energy levels (DE): 3,000 and 3,300 kcal kg-1 based on the sale of whole animals or fillet. This experiment was carried out into 50 m3 net cages in an aquaculture area located in Paranapanema River, Palmital - São Paulo State, Brazil, from November 21st, 2010 to January 21st. Economic performance indicators were: gross revenue, partial production cost, net revenue, leveling point, balance point, benefit cost ratio and cost of feed kg-1 gain. Twenty-nine percent of DP and 3,000 kcal DE kg-1 diet provided better economic performance for sale of whole fish, meaning higher net revenue (R$ 23.09 net cage-1) and benefit cost ratio (1.08), besides the lowest balance point (R$ 3.91 kg-1). Thirty-two percent of DP and 3,000 kcal DE kg-1 diet provided the lowest cost of feed kg-1 (R$ 2.53), leveling point (17.35 kg net cage-1) and balance point (R$ 13.63 kg-1), besides the highest benefit cost ratio (1.54) when the fish were sold in fillet form. Diets with 29% and diet with 32% digestible protein, both of them with 3,000 kcal of digestible energy kg-1 diet provides better economic responses in Nile tilapia reared in net cages (450 to 800 g), to be sold, respectively, whole or fillets form.(AU)
Avaliaram-se as respostas econômicas da produção de tilápia-do-nilo na fase de terminação (450 a 800 g), alimentadas com dietas contendo cinco níveis de proteína digestível (PD): 20, 23, 26, 29 e 32% e dois de energia digestível (ED): 3.000 e 3.300 kcal kg-1 de dieta, com base na venda de animais inteiros ou filés. A pesquisa foi conduzida em 50 tanques-rede (1 m3), em área aquícola localizada no rio Paranapanema, Palmital-SP, Brasil, de 21 de novembro de 2010 à 21 de janeiro de 2011. Os indicadores de desempenho econômico calculados foram: receita bruta, custo de produção parcial, receita líquida, ponto de nivelamento, ponto de equilíbrio, relação benefício custo e custo da ração kg-1. A dieta contendo 29% de PD e 3.000 kcal de ED kg-1 proporcionou melhor desempenho econômico para venda de peixes inteiros, ou seja, maior receita líquida (R$ 23,09 tanque-rede-1) e relação benefício custo (1,08), além do menor ponto de equilíbrio (R$ 3,91 kg-1). A dieta com 32% de PD e 3.000 kcal de ED kg-1 possibilitou para a venda de filés o menor custo da ração kg-1 (R$ 2,53), menor ponto de nivelamento (17,35 kg tanque-rede-1) e de equilíbrio (R$ 13,63 kg-1), além da mais alta relação benefício custo (1,54). A dieta contendo 29% e a dieta contendo 32% de proteína digestível, ambas com 3.000 kcal de energia digestível kg-1 proporcionam melhores respostas econômicas de tilápias-do-nilo recriadas em tanques-rede (450 a 800 g), ao serem vendidas, respectivamente, inteiras e na forma de filés.(AU)