Exigência proteica e respostas metabólicas de juvenis de piapara (Megaleporinus obtusidens)
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Data
2019-02-27
Autores
Almeida, Viviane do Nascimento Santana de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo do trabalho foi determinar a exigência proteica e os efeitos da proteína da dieta em indicadores fisiológicos e bioquímicos da piapara (Megaleporinus obtusidens). Para tanto, 300 juvenis (24 ± 1,26 g) foram distribuídos em 20 caixas de 130 L, totalizando 15 peixes/caixa. Foram formuladas 5 dietas isoenergéticas e com níveis crescentes de proteína digestível (21, 24, 27, 30 e 33% PD). Após 77 dias de alimentação, foi realizada a biometria dos peixes para avaliação dos parâmetros de desempenho produtivo e os indicadores fisiológicos: concentração de metabólitos no sangue (amônia sérica e triglicerídeos), relações somáticas, atividade hepática da alanina aminotransferase (ALT) e aspartato aminotransferase (AST) e atividade da enzima málica e glicose-6-fosfato desidrogenase (G6PDH). A cada sete dias, foram determinadas a concentração de amônia total, pH, condutividade elétrica e concentração de oxigênio dissolvido na água das caixas. O delineamento experimental foi inteiramente casualizado com 5 tratamentos e 3 repetições. Os resultados de desempenho produtivo foram submetidos à análise de variância (ANOVA) e à regressão polinomial. No peso final, taxa de crescimento específico, ganho de peso e conversão alimentar foi observado efeito linear (p<0,05) e no consumo não houve efeito significativo. Na concentração de amônia na água foi observada diferença (p<0,05), sendo observado efeito linear com o aumento de proteína. Na concentração de triglicerídeos sérico, amônia sérica, índice hepatossomático (IHS), concentração de glicogênio hepático e lipídio hepático, não foram observadas diferenças (p>0,05). No índice gorduro-viscerossomático (IGVS) e enzima málica, foi observado um efeito quadrático, com ponto máximo de 25,77% PD e 27,08% PD, respectivamente. No lipídio muscular e na atividade da G6PDH, houve um efeito linear, sendo observado nos animais que receberam a dieta com o menor nível proteico a maior concentração de lipídio. Na atividade hepática da AST houve um efeito linear, sugerindo um desbalanço de aminoácidos essenciais na dieta, enquanto a atividade da ALT não foi observada diferença (p>0,05). Nas condições experimentais do presente estudo, quando maior o nível de proteína digestível da dieta maior foi crescimento dos peixes, com reflexos nos indicadores fisiológicos dos peixes, não sendo possível a determinação da exigência proteica da piapara, sugerindo a necessidade de novos estudos.
The objective of this work was to determine the protein requirement and the effects of dietary protein on physiological and biochemical indicators of piapara (Megaleporinus obtusidens). For this, 300 juveniles (24 ± 1.26 g) were distributed in 20 boxes of 130 L, totaling 15 fish / box. Five diets were formulated isoenergetic and with increasing levels of digestible protein (21, 24, 27, 30 and 33% PD). After 77 days of feeding, the fish biometry was performed to evaluate the parameters of productive performance and the physiological indicators: concentration of metabolites in the blood (serum ammonia and triglycerides), somatic relations, liver enzymatic activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity and lipogenesis, malic enzyme and glucose-6-phosphate dehydrogenase (G6PDH). Every 7 days, the concentration of total ammonia, pH, electrical conductivity and oxygen concentration dissolved in the water of the boxes were determined. The experimental design was completely randomized, with 5 treatments and 3 replicates. The results of productive performance were submitted to analysis of variance (ANOVA) and polynomial regression. In the final weight, specific growth rate, weight gain and feed conversion was observed linear effect (p<0,05) and in consumption there was no significant effect (p>0,05). At the concentration of ammonia in the water, a significant difference (p <0.05) was observed with a linear effect. In the serum triglycerides concentration, serum ammonia, hepatosomatic index (HSI), level of hepatic glycogen and hepatic lipid, no significant differences were observed. In the fat-viscerosomal index (IGVS) and malic activity, a quadratic effect was observed, with a maximum point of 25.77 and 27.08% PD, respectively. In the muscle lipid level and G6PDH activity, there was a linear effect (p<0,05), where the animals that received the diet with the lowest protein level had the largest reserve. In the liver, a linear effect (p<0,05) was observed in the AST activity, suggesting an imbalance of essential amino acids in the diet, while in the ALT activity no significant difference was observed. At the experimental conditions, growth increased with increasing in the digestible protein, with reflexes on the physiological indicators of fish, and it is not possible to determine the protein content of piapara, suggesting the need for further studies.
The objective of this work was to determine the protein requirement and the effects of dietary protein on physiological and biochemical indicators of piapara (Megaleporinus obtusidens). For this, 300 juveniles (24 ± 1.26 g) were distributed in 20 boxes of 130 L, totaling 15 fish / box. Five diets were formulated isoenergetic and with increasing levels of digestible protein (21, 24, 27, 30 and 33% PD). After 77 days of feeding, the fish biometry was performed to evaluate the parameters of productive performance and the physiological indicators: concentration of metabolites in the blood (serum ammonia and triglycerides), somatic relations, liver enzymatic activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity and lipogenesis, malic enzyme and glucose-6-phosphate dehydrogenase (G6PDH). Every 7 days, the concentration of total ammonia, pH, electrical conductivity and oxygen concentration dissolved in the water of the boxes were determined. The experimental design was completely randomized, with 5 treatments and 3 replicates. The results of productive performance were submitted to analysis of variance (ANOVA) and polynomial regression. In the final weight, specific growth rate, weight gain and feed conversion was observed linear effect (p<0,05) and in consumption there was no significant effect (p>0,05). At the concentration of ammonia in the water, a significant difference (p <0.05) was observed with a linear effect. In the serum triglycerides concentration, serum ammonia, hepatosomatic index (HSI), level of hepatic glycogen and hepatic lipid, no significant differences were observed. In the fat-viscerosomal index (IGVS) and malic activity, a quadratic effect was observed, with a maximum point of 25.77 and 27.08% PD, respectively. In the muscle lipid level and G6PDH activity, there was a linear effect (p<0,05), where the animals that received the diet with the lowest protein level had the largest reserve. In the liver, a linear effect (p<0,05) was observed in the AST activity, suggesting an imbalance of essential amino acids in the diet, while in the ALT activity no significant difference was observed. At the experimental conditions, growth increased with increasing in the digestible protein, with reflexes on the physiological indicators of fish, and it is not possible to determine the protein content of piapara, suggesting the need for further studies.
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Palavras-chave
Nutrição, Piscitultura, Nativos, Enzimas, Nutrition, Fish farming, Natives, Enzymes