Abstract

SANDOVAL GONZALEZ, Laura et al. In vitro fermentation and the correlation of the nutritional content of leucaena associated with star grass. Rev. Mex. Cienc. Agríc [online]. 2016, vol.7, n.spe16, pp.3185-3196. ISSN 2007-0934.

The in vitro fermentation was determined by the technique of gas production of Leucaena leucocephala (Ll) and Cynodon nlemfuensis (Cn) 35, 42, 49, 56, 63 and 70 days of regrowth (DR) of an intensive silvopastoral system in San Luis Potosi, Mexico, in the windy season. A sample batch of fodder randomized, with three replications was taken by DR. The variables were: maximum volume (Vm; mL g-1), rate (S; h-1) and delay time (L; h) of gas production, and in vitro digestibility of dry matter (DIVMS): these they were correlated with mineral content and FDN, FDA, PC, EE, cellulose and lignin. The Vm, DIVMS and S were higher, and L lower for Ll with respect to Cn (0.039 vs 0.026 h-1; 258.9 vs 227.1 mL g-1; 63.6 vs 42.8%; and 1.93 vs 5.63 h). For both fodder Vm, DIVMS and S were higher (p< 0.05; 73.23 and 47.98%; 307 and 272 mL g-1; 0.044 and 0.29 h-1) at 35 DR. The DR affected the fermentation variable, the grass Cn greater than the Ll legume. The variables fermentation and DIVMS were negatively correlated (R= -0.681, p< 0.01) with FDA in both forages. To Leucaena, the EE was negative correlation (R= -0.68, p< 0.01); while for Cn it was positive correlation (R= 0.642, p< 0.01) with PC. Regarding minerals, the correlation was positive (p< 0.01) with P for both forages. In the legume, K, Fe and Cu was positively correlated (p< 0.01). It DIVMS only negatively correlated with Ca:P ratio for lecuaena. It was concluded that, according to the fermentation of Cn and Ll in a silvopastoral system, they should be grazed 35 DR, and increase in Cn content PC and P in Ll, which can be achieved by fertilizing with P and inoculating mycorrhizal.

Keywords : fiber; gas production kinetics; proximal analysis.