Corn substitution by mesquite bean flour (Prosopis juliflora) maintains growth and improves protein metabolism of Nile tilapia juveniles (Oreochromis niloticus).

The objective of this study was to evaluate the potential of mesquite bean flour (Prosopis juliflora) as an energy ingredient in extruded diets for juvenile Nile tilapia (Oreochromis niloticus). Two experiments were carried out: the first consisted of a study to evaluate the chemical composition and digestibility of the energy and nutrients of MBF; the second consisted of a growth test, in which juveniles consumed diets containing different proportions of corn substitution by MBF, in which zootechnical, hematological, physiological, and metabolic variables were evaluated. It was observed that MBF has a chemical composition similar to corn, as well as the apparent digestibility of energy and nutrients. The higher sucrose/starch ratio of the ingredient stands out, as well as the difference in digestibility (p < 0.05) between the predominant carbohydrates 87.63 and 99.25% for starch and sucrose, respectively. In the growth assay, no difference was observed between zootechnical variables (p > 0.05), and sucrase and alkaline phosphatase activities were increased (p < 0.05), which was not observed for amylase and lipase (p > 0.05). The hematological variables did not change (p > 0.05). Metabolic variables indicate a reduction in gluconeogenesis from amino acids, as can be seen by the reduction in liver transaminase levels (ALT and AST) and glutamate dehydrogenase (GDH), as well as the greater availability of free amino acids in plasmas (p < 0.05). Thus, it can be said that MBF has a high nutritional value and can totally replace corn in diets for juvenile tilapia and the metabolic findings indicate a potential protein-sparing effect.

Composição bromatológica e digestibilidade aparente de alimentos encontrados na região semiárida brasileira para arraçoamento de tilapia rosa em cultivos / Chemical composition and apparent digestibility of f eed found in the brazilian semiarid region for tilapia rosa feeding on cultivation

Neste trabalho, avaliou-se o coeficiente de digestibilidade aparente da matéria seca, proteína bruta e a energia digestível de seis alimentos (raspa de mandioca, grão de sorgo, feno de atriplex, feno de gliricídia, feno de leucena e resíduo de vitivinícola) disponíveis no semiárido brasileiro, para a tilápia rosa. As rações foram marcadas com 0,1 por cento de óxido crômico III. Utilizaram-se seis caixas circulares contendo 1000 litros de volume útil. Em cada caixa foi colocada uma gaiola circular de tela plástica, com 20 peixes cada (peso inicial de 80g). Os peixes foram arraçoados diariamente, três vezes ao dia. Para a coleta das fezes, cada gaiola foi colocada no início da noite em cubas de fibra de vidro cônicas com capacidade de 250L. O coeficiente de digestibilidade aparente dos ingredientes testados foi calculado com base no teor de óxido crômico III nas amostras de fornecidos e fezes, por análise de espectrofotometria de absorção atômica. Dentre os alimentos avaliados, os melhores valores de CDA para a MS foram referentes à raspa de mandioca e ao sorgo. Os melhores valores do CDA para a PB foram referentes à raspa de mandioca, sorgo e feno de gliricídia. O alimento avaliado com melhor valor de energia digestível foi o feno da atriplex.

This study evaluated the apparent digestibility coefficient of dry matter, crude protein and digestible energy (Kcal kg-1) for six ingredients (cassava chips, sorghum grain, atriplex hay, gliricídia hay, leucaena hay and wine residues) available in Brazilian semi-arid for pink tilapia feed. The feed were stained with 0.1 percent of chromic oxide III. A total of six circular tanks containing 1000 liters of volume were used. In each one was placed a circular cage of plastic screen with 20 fish each (initial weight of 80g). The fish were hand fed daily 3 times a day. To collect feces each cage was placed in the evening in conical 250L fiberglass tanks. Apparent digestibility of the ingredients tested was calculated based on the content of chromic oxide III in the samples offered and in the feces by atomic absorption spectrophotometry to the nutrient feed and feces, according to standard procedure. Among ingredients evaluated the best CDA values for MS were to cassava chips and sorghum. The best CDA values for CP were to cassava chips, sorghum and gliricidia hay. Atriplex hay was the ingredient with better digestible energy value.