Growth and antimicrobial activity of lactic acid bacteria from rumen fluid according to energy or nitrogen source

Abstract

-The objective of this study was to evaluate the effects of supplementation with different sources of energy and nitrogenous compounds on the in vitro growth and production of bacteriocin of lactic acid bacteria. Incubations were performed by using ruminal fluid from a rumen-fistulated Holstein-Zebu steer. The animal was kept on a Brachiaria decumbens pasture receiving 200 g/day of supplemental crude protein. Substrates and inoculum were placed in glass flasks considering eight treatments: cellulose, cellulose and casein, cellulose and soy peptone, cellulose and urea, starch, starch and casein, starch and soy peptone and starch and urea. Successive incubations were conducted to select microorganisms according to the energy sources and nitrogenous compounds. Starch favoured growth of lactic acid bacteria when compared to cellulose. Supplementation with true protein (soy peptone and casein) stimulated the growth of these bacteria when compared to the control (without supplementation with nitrogenous compounds). The addition of urea did not stimulate the growth of lactic acid bacteria. No antimicrobial activity was detected from colonies of isolated lactic acid bacteria. Sources of true protein increase the competition between non-structural and structural carbohydrates fermenting bacteria.

Nutritional aspects applied to grazing cattle in the tropics: a review based on Brazilian results

“…The NFC supply can actually increase the competition between fibrolytic and non-fibrolytic microbial species (EL-SHAZLY; DEHORITY; JOHSON, 1961;MOULD;ØRSKOV;MANN, 1983;COSTA et al, 2009;CARVALHO et al, 2011). In addition, because there is not enough nitrogen for adequate enzyme synthesis, the increase in NFC availability can increase the occurrence of energy spilling reactions in the non-fibrolytic microbial species, which will further decrease the efficiency of microbial growth (STROBEL; RUSSELL, 1986;SOUZA et al, 2010).…”

In vitro and in situ activity of carboxymethyl cellulase and glutamate dehydrogenase according to supplementation with different nitrogenous compounds

“…However, in the present study, competition between fibrolytic and non-fibrolytic species may exist (Carvalho et al, 2011) and the enhancement of fibrolytic bacteria (evidenced by an increase in CMCase activity) may be explained by considering the less favoured amylolytic bacteria, which use peptides more efficiently. Moreover, competition for nitrogenous compounds may favour cellulolytic bacteria when amino acids are provided because peptide assimilation by non-fibrolytic bacteria decreases the competitiveness of fibrolytic bacteria, which require more available nitrogen sources, such as amino acids and ammonia.…”

“…2 Differentials followed by * are different from zero according to the profile analysis (P<0.10). Table 5 -Concentration of ammonia nitrogen in rumen fluid (mg/dL) according to time after supplementation and nitrogen sources (in situ experiment) competition between groups of microbial species (Carvalho et al, 2011) because the favouring of a particular group reduces the production and efficiency of the other group, leading to a redistribution of microbial production among species groups in the environment. Cellulose is a linear polymer composed of β-1,4 glycosidic bonds with a simple primary structure and complex tertiary structure.…”

“…In a recent study, Carvalho et al (2011) reported that true protein supplementation stimulates the growth of nonfibrolytic bacteria possibly because this nitrogen source is not well used by fibrolytic bacteria.…”

Consumo e dinâmica ruminal da fibra em detergente neutro em bovinos em pastejo no período das águas recebendo suplementação com nitrogênio não-proteico e/ou proteína verdadeira

“…Esses efeitos deletérios da suplementação exclusiva com proteína verdadeira sobre a utilização de carboidratos fibrosos, denominados "efeito proteína" (Costa et al, 2009) são comumente observados na literatura (Cone & Van Gelder, 1999;Oliveira et al, 2005) e parecem estar associados ao estímulo sobre o crescimento de espécies não-fibrolíticas, ampliando a competição por substratos essenciais no ambiente ruminal (Carvalho et al, 2011).…”