O experimento objetivou estimar as exigências de proteína bruta (PB) e energia metabolizável (EM) para máximo desempenho de machos de codornas japonesas criadas para a produção de carne e determinação da idade de abate que resultasse em peso máximo das aves. Quatrocentos e cinqüenta codornas foram utilizadas em delineamento experimental de blocos ao acaso, com cinco repetições de seis codornas por unidade experimental. Os tratamentos, de dietas formuladas a partir da combinação de cinco níveis de PB (18, 20, 22, 24 e 26%) e três níveis de EM (2800, 3000 e 3200kcal/kg de ração), foram alocados nas parcelas e os quatro períodos experimentais nas sub-parcelas. As variáveis estudadas durante os quatro períodos (5 a 16; 16 a 27; 27 a 38 e 38 a 49 dias de idade) foram consumo de ração (CR), ganho de peso (GP), conversão alimentar (CA) e peso vivo (PV). No período total (5 a 49 dias de idade) foram estudados consumo de ração acumulado (CRA), ganho de peso acumulado (GPA) e conversão alimentar acumulada (CAA). As exigências estimadas de PB e EM durante o primeiro (5 a 16) e terceiro (27 a 38) períodos foram 26 e 2800 e 18% e 3200kcal/kg de ração, respectivamente. A exigência de PB no segundo período (16 a 27 dias de idade) foi de 26%, não sendo possível estimar a exigência energética. No quarto (38 a 49 dias de idade) período experimental a exigência estimada de EM foi de 3200kcal/kg de ração, não sendo possível estimar a exigência protéica. No período total as exigências protéica e energética, estimadas para máximos ganhos de peso acumulados, foram de 26% e 3200kcal/kg de ração, respectivamente. As idades estimadas que resultaram em PV máximo dependeram do nível de PB e de EM da dieta, variando de 57 a 85 e 60 a 74 dias, respectivamente.

This study evaluated the effects of high phytase doses and soybean meal ( SBM ) with different CP content on growth performance, ileal nutrient digestibility, digestible energy, plasmatic myo -inositol, phosphate release in vitro, and bone composition of broiler chickens. One thousand two hundred 1-day-old broilers were distributed in a 2 × 2 completely randomized factorial arrangement, with 2 phytase doses (1,000 and 2,500 phytase units [ FYT ]/kg of feed) and 2 SBM with different CP concentrations (45 and 47%), totaling 4 treatments with 12 replicates of 25 birds each. The chickens received feed and water ad libitum. Diets were based on corn and SBM, with different inclusions of soybean hull used to dilute the CP content of SBM according to each treatment. The inclusion of 2,500 FYT increased weight gain from 0 to 21 d ( P < 0.05), whereas growth performance from 22 to 42 d was not affected, and SBM had no effect on growth performance. At day 21, ileal digestibility of dry matter, ash, and P, and digestible energy were greater in diets with 2,500 FYT/kg ( P < 0.05), as well as phosphate in vitro release ( P < 0.01) compared to the lower dose. At day 42, diets with SBM 47% CP and 2,500 FYT/kg promoted greater digestibility of dry matter, ash, CP, Ca, P, and digestible energy ( P < 0.001), and greater phosphate release ( P < 0.05) in comparison to other treatments. myo -inositol level in the plasma at 21 and 42 d was higher with the use of 2,500 FYT compared to 1,000 FYT ( P < 0.05). The higher phytase dose increased tibia ash, toe ash, and Seedor Index ( P < 0.05) at day 21, and the Ca content in tibia was higher with 2,500 FYT and SBM 47% CP at day 42. In conclusion, higher phytase doses for broilers improve weight gain, myo -inositol provision, and bone mineral composition. Nutrient ileal digestibility can be enhanced by higher phytase doses when in combination with SBM of greater nutritional quality.

We evaluated the influence of enzymatic supplementation on the growth performance and cecal microbiota of broilers. A total of 2160 1-day-old male chicks were used in a 3 × 2 × 2 factorial arrangement (three corn hybrids, two drying temperatures −80 and 110 °C, with or without the inclusion of an enzymatic blend (amylase, xylanase, and protease) (20 birds/pen, n = 9). For all performance and digestibility parameters, we observed, in general, isolated effects of the corn hybrids and drying temperature. Birds that received the enzymatic blend in the diet showed better weight gain from 1 to 21 days (d) and better digestibility coefficients of nutrients at 42 d. Birds fed diets with corn dried at 80 °C showed a better feed conversion ratio from 1 to 42 d. At 21 d of age, enzymatic supplementation had positive effects on jejunum morphology. Enzyme supplementation increased the abundance of the phylum Tenericutes, class Bacilli and Mollicutes, reduced Clostridia, and increased the abundances of the families Lactobacillaceae, Anaeroplasmataceae, and O_RF39;F. In conclusion, the addition of amylase, xylanase, and protease led to a better nutrient digestibility, performance, and intestinal morphology. In addition, enzyme supplementation changed the diversity, composition, and predicted function of the cecal microbiota at d 21.

According to scientific literature, glycerol in the diet can spare glucogenic amino acids by inhibiting the activity of enzymes, such as glutamate dehydrogenase, thereby promoting protein deposition in muscle tissues. Therefore, the objective of this study was to evaluate the effect of three sources of glycerine (crude glycerine from soybean oil--CGSO, mixed crude glycerine from frying oil and lard--MCG and a semipurified glycerine from soybean oil--SPGSO) in four concentrations in the diet (17.5, 35.0, 52.5 and 70.0 g of each type of glycerine/kg of feed) on the activity of hepatic glutamate dehydrogenase, performance and protein content in the breast of broilers, during 22-35 days of age (experiment I) and 33-43 days of age (experiment II). In both experiments, an increase in MCG induced a linear decline in glutamate dehydrogenase activity (p < 0.05). In contrast, increasing the concentration of SPGSO in the diet caused a linear increase in enzyme activity (p < 0.05). There was no (p > 0.05) isolated effect of glycerine on the enzyme activity in either evaluated phase; however, during 33-42 days of age, MCG inhibited (p < 0.05) the glutamate dehydrogenase activity by up to 34.43%. During 22-35 days of age, the diet containing SPGSO induced a higher protein content (p < 0.05) in the breast, and regardless of the source utilized, the maximum protein deposition was estimated (p < 0.05) when broilers were fed with 55.08 g glycerine/kg of diet. There was no (p > 0.05) interaction or isolated effects of the sources and levels of glycerine on the protein content in the breast of broilers at 33-42 days of age, and moreover, all diets containing glycerine promoted a similar protein deposition in the breast compared with birds that received the diet without glycerine. The bird age also showed to influence the feed intake and weight gain of broilers fed diet containing glycerine. It is concluded that for both rearing phases, an increase in glycerine in the diet did not necessarily reduce the glutamate dehydrogenase activity, and the protein deposition in the breast of broilers may not be strictly correlated with the activity of this enzyme.

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