Consumo, digestibilidade e balanço de nitrogênio de rações contendo diferentes teores de torta de murumuru em dietas para ovinos

Abstract

This study aimed to assess the potential use of increasing levels of murumuru cake (Astrocaryum murumuru var. murumuru, M art.) (MC) in sheep diets as a replacement for Mombasa grass (Panicum maximum Jacq). Metabolic tests were performed with 20 castrated male sheep at Embrapa Amazônia Oriental, Belém, Pará, during 26 days. The experiment was arranged in a completely randomized design, with five diets and four replications. MC0: 100% grass; MC10: 10% MC and 90% grass; MC20: 20% MC and 80% grass; MC40: 40% MC and 60% grass; and MC60: 60% MC and 40% grass. The intake and the coefficient of apparent digestibility of dry matter (DMI and CDDM), organic matter (OMI and CDOM), crude protein (CPI and CDCP), neutral detergent fiber (NDFI and CDNDF), acid detergent fiber (ADFI and CDADF), ether extract (EEI and CDEE), cellulose (CELI and CDCEL), hemicellulose (HEMI and CDHEM), and nitrogen balance (NB) of experimental diets were determined. The intake of mineral material (MMI) and lignin (LIGI) were also determined. The DMI, OMI, MMI, CPI, NDFI, and ADFI displayed a decreasing linear effect with the replacement of Mombasa grass by MC in the diet. The EEI and the LIGI presented quadratic effects according to the replacement levels of MC in the diet. The CDDM, CDOM, and CDHEM displayed increasing linear effects, between MC0 and MC60. The CDEE, CDNDF, CDADF, and CDCEL displayed a quadratic effect, with optimum replacement levels of 56.65%, 41%, 31.33%, and 27.46%, respectively. The nitrogen balance presented a negative linear effect in the range of 0% to 60% of murumuru cake. One can conclude that murumuru cake is an alternative to the dietary supplementation of ruminants in replacing the Mombasa grass because it provides an increase in the digestibility of nutrients for sheep. However, a limited replacement level must be implemented, considering that from 27.46%, 31.33%, 41%, and 56.65% replacement, a decline occurs in the CDCEL, CDADF, CDNDF, and CDEE, respectively, although a negative nitrogen balance does not occur.