Author(s): Angel R, Dalloul RA, Doerr J
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Abstract From hatch to 18 d of age broilers were fed starter diets with (0.9 kg/ton) or without direct fed microbial (DFM). At 18 d, birds were weighed and, within DFM treatment (trt), randomly assigned to battery pens. In Exp 1, a 2 x 2 factorial arrangement of nutrient density [control (C, 19.3\% protein (CP), 0.84\%, Ca 0.37\% nonphytin P (nPP); and 17.1\% CP, 0.8\% Ca, and 0.3\% nPP in the grower (Gr) and finisher (Fn) diets, respectively) and moderate (M) (17\% CP, 0.69\% Ca, 0.30\% nPP; 15\% CP, 0.66\% Ca, 0.25\% nPP in the Gr and Fn diets, respectively)] and DFM concentration [0 or 0.9 kg/ton (++)] was used. Exp 2 was a 2 (DSM at 0 and 0.45 kg/ton) x 3 (nutrient densities) factorial. Exp 2 included a low (L) nutrient density that differed from diet M only in Ca and nPP concentrations and an added trt, diet M with 0.45 kg/ ton DFM as in Exp 1. At the end of the Gr and Fn weight, feed efficiency, apparent nutrient retention were determined, and 4 birds per pen were sampled for tibia ash. In Exp 2, gains in the Gr phase were 1,122.0, 983.7, 1,121.5, 930.7, and 1,151.5 g in birds fed the C, M, M+, L, and L+ diets, respectively. Addition of DFM to the M diet overcame the negative effect of nutrient concentration on performance but not when the L diet was fed. Nutrient level and DFM affected apparent protein, Ca, and P retention at 32 or 42 d of age with retention increasing as nutrient level decreased and with DFM added to the diet. Ca and P retention at 28 d (Exp 1) was higher in birds fed M++ (45.8 and 46\%, respectively) than in those fed the C diet (38.7 and 40.0\%, respectively). Feeding the M and L diets resulted in lower tibia ash than that of birds fed the C diet, but the addition of DFM to low nutrient diets overcame this negative effect.
This article was published in Poult Sci
and referenced in Biological Systems: Open Access