Métodos de coleta de fezes e determinação dos coeficientes de digestibilidade da fração protéica e da energia de alimentos para o pacu, Piaractus mesopotamicus (Holmberg, 1887)

Abstract

To improve the pacu (Piaracatus mesopotamicus) feeding in the growth phase, it's necessary to know the digestibility of the ingredients used in his diets. Initially, four fecal collection methods were analyzed (dissection, stripping, Guelph and modified Guelph), based on precision and versatility and also the most efficient time among fecal collection of the Guelph sedimentation systems, through crude protein digestibility coefficient of pacu basic diet. There was no difference among the fecal collection methods while the intervals of time among the collections were significantly different, which may interfere in the protein digestibility results. In a second stage, five proteins concentrated of animal origin, five of vegetable origin and four energetic were studied for estimating protein and energy digestibility coefficients using the stripping method. The rations contained 69.5% of a reference diet, 30.0% of the ingredient test and 0.5% of Cr2O3. In a general way, crude protein digestibility coefficients were high and did not differ from the wheat meal (93.89%) and feather flour (75.73%), respectively. However, blood and yeast showed lower crude protein digestibility (57.72% and 68.86%), respectively. Gross energy digestibility coefficients varied considerably among the feedstuffs, showing high values (above 90%) for the sorghum, rice meal and raw and toasted soy and lower values (smaller than 70%) for poultry by-product and blood meal, soybean meal, cotton and yeast. However, with regard to the fecal collection methods, the results showed that anyone can be adopted with safety for digestibility determination, if used accurately. In a general way, most of protein concentrate can be used as a very good protein source, except for blood meal and the yeast. The energy concentrate revealed to be a source of energy in pacu diets.