Digestibilidade aparente de dietas práticas com diferentes relações energia:proteína em juvenis de pirarucu

The objective of this work was to determine the apparent digestibility of nutrients and energy of diets for pirarucu (Arapaima gigas) juveniles. Eight experimental diets containing four energy:protein ratios (11, 10.1, 9, 8 kcal digestible energy per gram of crude protein) and two non-protein energy sources (soybean oil and poultry fat) were tested in a 4x2 factorial scheme, in triplicates. Two hundred and forty pirarucu juveniles weighting 96.8±2.3 g were distributed in 24 cylindrical-conical fiberglass tanks, adapted for feces collection (modified Guelph system). Fish were fed twice a day to apparent satiation, with experimental diets containing 0.5% of chromium oxide as inert marker in order to determine the apparent digestibility coefficients. Diets containing an energy:protein ratio of 9 kcal digestible energy per gram of crude protein resulted in significantly lower apparent digestibility coefficient for dry matter, crude protein and non-nitrogenous extract. The highest apparent digestibility coefficients for crude fat was obtained with soybean oil. The dietary energy:protein ratio influences the nutrient and energy apparent digestibility coefficients to pirarucu juveniles

Effects of the dietary protein : lipid ratio on growth and nutrient utilization in gilthead seabream (Sparus aurata L.)

International audienc

Optimum dietary crude protein requirement for juvenile cachama Piaractus brachypomus Exigência ótima de proteína bruta para juvenis de pirapitinga, Piaractus brachypomus

A growth experiment was conducted to determine the optimal dietary protein requirement for juvenile cachama, Piaractus brachypomus. Six semi-purified isoenergetic experimental diets using casein and gelatin as protein sources were formulated to contain graded levels of protein (16, 20, 24, 28, 32 and 36%). Fish initially averaging 15.52&plusmn;0.33g (mean&plusmn;SD) were randomly distributed into the tanks (500L) as groups of 20 fish and fed to apparent satiation twice daily for 60 days. The results showed that feed consumption, feed conversion ratio, fish weight gain, specific growth rate, protein efficiency ratio and protein productive value were affected by dietary protein level (P<0.05) . No significant differences were observed in proximal composition of carcass (P<0.05) in response to dietary protein. Analysis of dietary protein level x WG with a second order polynomial regression suggested a requirement of 31.6% CP for optimum growth.<br>O presente experimento foi realizado para determinar o requerimento ótimo de proteína em dietas para juvenis de pirapitinga, Piaractus brachypomus. Foram formuladas seis dietas experimentais semi-purificadas, iso-energéticas e com diferentes níveis de proteína (16, 20, 24, 28, 32 e 36% de PB) usando caseína e gelatina como fontes de proteína. Os peixes com peso inicial 15,52&plusmn;0,33g (média&plusmn;SD) foram distribuídos aleatoriamente em grupos de 20 animais por tanque; foram alimentados durante 60 dias, duas vezes/dia até aparente saciedade. Os resultados mostraram que o consumo de alimento, taxa de conversão de alimento, ganho de peso, taxa de crescimento específico, taxa de eficiência de proteína e valores produtivos da proteína e da energia foram significativamente afetados pelos níveis de proteína das dietas (P<0,05). Não foram observadas diferenças significativas na composição proximal da carcaça (P<0,05) entre tratamentos. A análise do ganho de peso em função dos níveis de proteína da dieta, realizada utilizando regressão polinomial de segundo grau, deu um requerimento de 31,6% de proteína para ótimo crescimento de juvenis de pirapitinga