Effect of the tropical forage calliandra on microbial protein synthesis and ecology in the rumen

Abstract

Aims: To determine the effect of condensed tannins in Calliandra calothyrsus (calliandra) on rumen microbial function. Methods and Results: Microbial populations, ruminal protein synthesis and fermentation end-products were measured in sheep fed roughage hay supplemented with calliandra (30%), with and without inclusions of polyethylene glycol (PEG) to counteract the effect of tannin. Molecular and conventional enumeration techniques were used to quantify rumen bacteria, fungi and protozoa, and protein synthesis was predicted from estimates of urinary purine excretion. The total number of cellulolytic bacteria, including populations of Fibrobacter succinogenes and Ruminococcus spp., was signi®cantly lower in sheep supplemented with calliandra and these populations increased when animals were treated with PEG. By contrast, protozoa and fungi and the microbial group containing Bacteroides-Porphyromonas-Prevotella bacteria appeared to be less affected. The ef®ciency of microbial protein synthesis in the rumen was not altered signi®cantly. Conclusions: Calliandra caused signi®cant shifts in rumen microbial populations without changing the ef®ciency of protein synthesis. Signi®cance and Impact of the Study: The effect of calliandra tannins on rumen digestion may result more from complexing with nutrients than direct inhibition of micro-organisms.

Eubacterium pyruvativorans sp. nov., a novel non-saccharolytic anaerobe from the rumen that ferments pyruvate and amino acids, forms caproate and utilizes acetate and propionate

“…It was similar to these other isolates in its ability to grow on trypticase in the absence of sugars, its non-saccharolytic metabolic properties and its sensitivity to monensin. Like most of the isolates obtained in this way, with the exception of the Clostridium botulinum-like isolate Lp1284 (McSweeney et al, 1999), it was not proteolytic. Most importantly from the point of view of ruminal ecology, isolate I-6 T produced NH 3 rapidly from amino acids.…”

“…Strain I-6 T thus appeared to be typical of the nonsaccharolytic HAP bacteria isolated from the rumen first by Russell and his colleagues , 1989Paster et al, 1993;Russell et al, 1988) and subsequently by Attwood et al (1998) and McSweeney et al (1999). It was similar to these other isolates in its ability to grow on trypticase in the absence of sugars, its non-saccharolytic metabolic properties and its sensitivity to monensin.…”

Associative effects between forages on feed intake and digestion in ruminants

“…Dietary-condensed tannins (CT), occurring particularly in legumes such as sainfoin (Onobrychis vicifolia) and Lotus corniculatus L., bind to proteins inhibiting their degradation in the rumen (McSweeney et al, 2001b). When dietary protein concentrations are low and fibre concentrations are high, CT are detrimental, decreasing digestibility, intake and animal performance by limiting microbial growth (Min et al, 2005), fibrolytic activity (McSweeney et al, 2001a) or amino-acid absorption from the intestine (Waghorn, 2008). However, when protein concentrations exceed animal requirements for CP, these effects can improve performance (Barry and McNabb, 1999).…”

Efeito dos taninos condensados de forrageiras nativas do semi-árido nordestino sobre o crescimento e atividade celulolítica de Ruminococcus flavefaciens FD1

“…Pouca atenção foi dada à interação entre os taninos e os microrganismos ruminais (McSweeney et al, 2001).…”

“…Essas plantas, a exemplo da maioria das leguminosas tropicais, A presença de taninos na dieta diminui a digestibilidade dos carboidratos fibrosos, levando a decréscimo na produção de ácidos graxos voláteis, de gases e do valor energético dos alimentos (Kumar e Singh, 1984). Esses efeitos são atribuídos às ligações dos taninos solúveis com componentes da parede celular, tendo como resultado complexos indigestíveis ou inacessíveis às enzimas bacterianas (CanoPoloche, 1993), à redução da atividade enzimática, com inativação de importantes enzimas microbianas, ou ainda a uma modificação da microflora, devido à ação bacteriostática ou bactericida do tanino (Kumar e Vaithiyanathan, 1990;Nelson et al, 1997;Mcsweeney et al, 2001). …”