This paper were carried out with caecectomised broilers for evaluation of the effects of the feed intake levels on the methodology of forced feeding, for evaluation of the metabolizable energy (apparent metabolizable energy - AME, true metabolizable energy - TME, apparent corrected by the nitrogen metabolizable energy - AMEn and true corrected - TMEn), using as feeds tests the wheat and some of its by-products randomly distributed in fatorial outline of 2 x 8, (levels x feeds) with four repetitions. The method used for the evaluation of ME was the forced feeding. All the broilers were submitted to a fast of 30 hours and forced to ingest 25 and 50 grams of the pure feeds of an only time. In the two levels a treatment was left in fast, for the determination of the metabolic losses and endogenous. In the feeds and excrete, dry matter, crude protein and gross energy they were analyzed. The averages were compared by the test of Student Newman Keuls. Evaluated the effects of the consumption levels on the metabolizable energy obtained by the methodology of Sibbald, it was observed that the values of AME for over all treatments were affected for the amount of ingested feed, and in the lowest consumption level the values of AME were significantly lower. Wheat bran and the by-products values obtained for TME were higher in the level of lower consumption. With regard to the relationship AME/TME, would be logical to wait larger relationships at low consumption levels, as well as it was found, once the effects of the metabolic and endogenous losses present larger influences in the calculation of TME in low ingestions. AMEn was affected strongly by the ingestion levels, presenting significant differences in all the treatments. These results are due to the excretion of metabolic fecal energy (FEm) more the energy endogenous urinary (EUe) that depresses the values of EMA in low consumptions. With relationship TMEn, only the clear wheat flour shown difference among the feeds tested, with lowest value of TMEn in the smallest consumption level. The other treatments did not show any significant differences. The relationship between AMEn and TMEn was larger in the smallest consumption levels.
Birds; forced feeding; consumption levels; metabolizable energy
