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In order to determine the effect of three collections of Tithonia diversifolia (mv-12, mv-14 and mv-17), collected in the eastern region of Cuba, on the ruminal microbial population of cattle, an experiment under in vitro conditions was developed. The control treatments with Cynodon nlemfuensis (star grass) were compared: star grass + mv-12; star grass + mv-14 and star grass + mv-17. The three collections were included at a rate of 20 % of the dry matter. The crude protein content was 19-23 % of the dry matter. With the materials mv-14 and mv-17 higher populations of cellulolytic bacteria were obtained, at three and six hours after starting fermentation with respect to that obtained with star grass. The three collections doubled the population of proteolytic bacteria three hours after starting fermentation, while at six hours only mv-12 produced effects in this bacterial group. The methane values were 37.4, 32.6, 33.2 and 32.33 g/kg of digested organic matter for the control, and the treatments mv-12, mv-14 and mv-17, respectively. Although they did not differ between plant materials, mv-12, mv-14 and mv-17 produced less methane than the star grass treatment only (P = 0.0477). It is concluded that the treatments mv-12, mv-14 and mv-17 caused modifications in the ruminal ecosystem, by increasing the population of total cellulolytic organisms and proteolytic bacteria; in addition to reducing the protozoan population. The methane estimated from crude protein concentration also decreased. [ABSTRACT FROM AUTHOR]

In order to study the effect of five inclusion levels of mulberry (Morus alba cv. cubana) on methanogens and some main cellulolytic populations within rumen liquor of water buffalos (Bubalus bubalis), and contribute to the knowledge of the action mechanism by which the Cuban variety of mulberry reduces ruminal methanogenesis, an in vitro fermentation was carried out and five inclusion levels (0, 15, 20, 25 and 30%) of M. alba vc. cubana to a diet based on star grass (Cynodon nlemfuensis) were evaluated. Total, methanogenic and cellulolytic (Fibrobacter succinogenes, Ruminococcus albus) bacteria, and fungi were identified and quantified by polymerase chain reaction in real time. The percentage of cellulolytic and methanogenic bacteria, regarding total bacteria population was evaluated, as well as the delta delta Ct (ΔΔCt) and the expression of different ruminal microbial populations, in relation to control treatment. The inclusion of M. alba cv. cubana did not affect the studied ruminal microbial populations. The percentage of representation of F. succinogenes, R. albus and methanogens, regarding total bacteria was not affected with the inclusion of this variety of mulberry on the diet. Values of ΔΔCt and expression relative to control treatment of microbial populations evidenced that diets containing mulberry tree had the same difference and the same expression relative to the control treatment. It can be concluded that inclusion of M. alba cv. cubana on diet not affect the main microbial populations that degrade the fiber in the rumen, which could be used as a strategy for reducing methane production in the rumen. The mechanism by which this plant is able to reduce ruminal methanogenesis is not through direct effect on methanogens. [ABSTRACT FROM AUTHOR]

Objective. Determine the population density of cellulolytic bacteria, Butyrivibrio fibrisolvens and the concentration of vaccenic acid, by supplementing diets consisting of kikuyu grass (Pennisetum clandestinum Hoechst. Ex Chiov.) as base ingredient, together with cassava flour and biomass (effluent from ethanol production) in rumen simulator-Rusitec. Materials and methods. Four treatments (T) were evaluated, these were composed as: T1/Control 1: 100% kikuyu grass with a total protein intake of 23.9%, T2: a mixture of 70% kikuyu grass, 20% biomass and 10% cassava flour with a total protein intake of 19.4%; T3/Control 2: 100% kikuyu grass, with a 17.8% protein intake and T4: 70% kikuyu grass, 20% biomass and 10% cassava flour with a 15.3% protein intake. One and two-way variance analysis was made and the Pearson correlation coefficient was determined. Results. An increase was observed in the population density of viable cellulolytic bacteria (CFU/ml) and B. fibrisolvens statistically significant (p<0.005) with treatment T2, in contrast to T1, T3 and T4 treatments. In addition, there was a significant increase in the concentration of vaccenic acid (mg/L) in the ruminal content in Rusitec with the same treatment (T2). Conclusions. Results obtained in this ruminal simulation study are evidence to the benefits of kikuyu grass together with cassava flour and biomass diet implementation on the growth of ruminal cellulolytic and B. fibrisolvens bacteria, as well as on the production of vaccenic acid. The study also suggests the nutritional potential that such supplements could provide to grazing bovine feeding. [ABSTRACT FROM AUTHOR]