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In vitro ruminal fermentation dynamics of isoenergetic (10.9 MJ ME kg-1) and isoproteic (12.1% CP) diets for cattle were determined, with gradual replacement levels of 0.0 (T0, control), 32.4 (T32), 77.6 (T78) and 100.0 % (T100) of ground corn grain, on a dry basis, mainly by integral sweet potato silage. Accumulated gas production during the 96 h of in vitro fermentation was analyzed with a mixed generalized linear model. the increases in gas production during the initial stage were 73.0, 80.0, 98.0 and 103.8, in the intermediate stage were 82.0, 75.5, 73.2 and 70.5, and in the final were 50.0, 51.8, 45.2 and 44.8 mL g-1 of incubated organic matter (incOM) for T0, T32, T78 and T100, respectively. In the initial stage, the highest increases of T78 and T100 were attributed to the greater availability of soluble carbohydrates and sugars. In the intermediate period, the increase in T0 was explained by the degradation of protein matrix that surrounds corn starch. In the final stage, the lower increases were related to the limited availability of fermentable substrates and microbial recycling. On average, T78 and T100 showed greater fermentative potential (259.2 mL.g-1 incOM), microbial efficiency rate (0.13), maximum speed (12.4 mL.g-1 incOM h-1) and less time to reach maximum speed (9.90 h). It is concluded that, in in vitro conditions, diets with sweet potato integral silage provided greater nutrient availability for ruminal microorganisms, which favors energy supply for the different metabolic processes in the rumen. [ABSTRACT FROM AUTHOR]

The effect of the inclusion of Moringa oleifera in the nutritional value of silages of C. purpureus cv. Cuba CT-169 was evaluated mixed in five proportions (100.0, 80:20, 60:40, 40:60 and 20:80, humid base). The chemical composition of the silage improved in terms of a higher crude protein and lower neutral detergent fibre when M. oleifera was included (P˂0.00). The analysis of the in vitro gas production showed an interaction between the two factors in the three phases of the fermentation (P˂0.05). In the initial and in the intermediate phase the highest gas production was in the treatments with Moringa oleifera respect to the silage of C. purpureus. Nevertheless, in the final phase the silage gas production of C. purpureus was higher respect to the others at 96 and 120 hours. Kinetic parameters indicated that 100 % of C. purpureus tended to show the highest fermentative potential (113.3 mLg-1 OM inc). The highest Vmax was obtained with the silage of 60 % of M. oleifera (0.739 mL.g-1 OM inc h-1), although the lowest TVmax was reached with 40 % of M. oleifera. Silage with 40 % of M. oleifera showed the highest MBS in relation to the other treatments, except in silage with 20 % of the tree plant (P˂0.05). It is concluded that the inclusion of the M. oleifera in mixed silage improved the nutritive quality of the products obtained when levels of proteins are increased and those of NDF are reduced respect to the grass used. Silage with 40 % of inclusion of M. oleifera was the best combination due to the adequate levels of CP and lower NDF and also its fermentation indicated higher Vmax, lower TVmax and higher microbial efficiency in comparison to other treatments. [ABSTRACT FROM AUTHOR]

An experiment was conducted under in vitro conditions for determining the effect of a raw saponin extract on the ruminal microbial population and in vitro methane production with star grass (Cynodon nlemfuensis) substrate. Treatments were designed according to the quantity of saponin extract: 1) control, without saponins, 2) 0.6 %, 3) 1.2 % and 4) 1.8 % of the DM of raw saponin extract. The basal diet was star grass (C. nlemfuensis). The saponin extract was obtained from Sapindus saponaria fruit and its saponin content was of 139.5 mg, equivalent of diogenin.mL-1. There was a reduction in protozoa population, regardless the saponin level. Its effect on the main cellulolytic bacteria, determined by PCR-RT, showed that the amount of Fibrobacter succinogenes was not modified while the values of Ruminococcus albus were 25.92; 26.72; 25.2 and 22.35 CT for the levels 0; 0.6; 1.2 and 1.8 %, respectively. The acetic acid concentration was not modified by the saponins; the propionic was reduced with 1.2 % inclusion. The concentration of valeric acid was 0.68; 0.62; 0.52 and 0.49 mmol.L-1 for 0, 0.6; 1.2 and 1.8 % of saponin extract, respectively. Saponins increased methanogenic representation and methane production. It is concluded that the saponin extract modulates the fermentative process on reducing protozoa, does not modify the presence of F. succinogenes and decreases that of R. albus, probably due to the fact that both utilize the same resource, space and carbon source in the rumen. The quantity of methanogens was higher with 1.2 and 1.8 % coinciding with the highest methane production. [ABSTRACT FROM AUTHOR]

An experiment was conducted under in vitro conditions for determining the effect of a raw saponin extract on the ruminal microbial population and in vitro methane production with star grass (Cynodon nlemfuensis) substrate. Treatments were designed according to the quantity of saponin extract: 1) control, without saponins, 2) 0.6 %, 3) 1.2 % and 4) 1.8 % of the DM of raw saponin extract. The basal diet was star grass (C. nlemfuensis). The saponin extract was obtained from Sapindus saponaria fruit and its saponin content was of 139.5 mg, equivalent of diogenin.mL-1. There was a reduction in protozoa population, regardless the saponin level. Its effect on the main cellulolytic bacteria, determined by PCR-RT, showed that the amount of Fibrobacter succinogenes was not modified while the values of Ruminococcus albus were 25.92; 26.72; 25.2 and 22.35 CT for the levels 0; 0.6; 1.2 and 1.8 %, respectively. The acetic acid concentration was not modified by the saponins; the propionic was reduced with 1.2 % inclusion. The concentration of valeric acid was 0.68; 0.62; 0.52 and 0.49 mmol.L-1 for 0, 0.6; 1.2 and 1.8 % of saponin extract, respectively. Saponins increased methanogenic representation and methane production. It is concluded that the saponin extract modulates the fermentative process on reducing protozoa, does not modify the presence of F. succinogenes and decreases that of R. albus, probably due to the fact that both utilize the same resource, space and carbon source in the rumen. The quantity of methanogens was higher with 1.2 and 1.8 % coinciding with the highest methane production. [ABSTRACT FROM AUTHOR]