Effects of natural plant extracts on ruminal protein degradation and fermentation profiles in continuous culture1

Abstract

Eight dual-flow continuous culture fermenters were used in four consecutive periods of 10 d to study the effects of six natural plant extracts on ruminal protein degradation and fermentation profiles. Fermenters were fed a diet with a 52:48 forage:concentrate ratio (DM basis). Treatments were no extract (CTR), 15 mg/kg DM of a mixture of equal proportions of all extracts (MIX), and 7.5 mg/kg DM of extracts of garlic (GAR), cinnamon (CIN), yucca (YUC), anise (ANI), oregano (ORE), or pepper (PEP). During the adaptation period (d 1 through 8), samples for ammonia N and VFA concentrations were taken 2 h after feeding. On d 9 and 10, samples for VFA (2 h after feeding), and peptide, AA, and ammonia N concentrations (0, 2, 4, 6, and 8 h after feeding) were also taken. Differences were declared at P < 0.05. During the adaptation period, total VFA and ammonia N concentrations were not affected by treatments. The acetate proportion was higher from d 2 to 6 in CIN, GAR, ANI, and ORE, and the propionate proportion was lower from d 2 to 4 in CIN and GAR, and from d 2 to 5 in ANI and ORE, compared with CTR. However, the proportion of individual VFA (mol/100 mol) was similar in all treatments after d 6, except for valerate in d 9 and 10, which was lower in PEP (2.8 +/- 0.27) compared with CTR (3.5 +/- 0.27). The average peptide N concentration was 31% higher in MIX, and 26% higher in CIN and YUC compared with CTR (6.5 +/- 1.07 mg/100 mL). The average AA N concentration was 17 and 15% higher in GAR and ANI, respectively, compared with CTR (7.2 +/- 0.77 mg/100 mL). The average ammonia N concentration was 31% higher in ANI and 25.5% lower in GAR compared with CTR (5.5 +/- 0.51 mg/100 mL). The accumulation of AA and ammonia N in ANI suggested that peptidolysis and deamination were stimulated. The accumulation of AA N and the decrease in ammonia N in GAR suggests that deamination was inhibited. The accumulation of peptide N and the numerical decrease in AA N in CIN suggest that peptidolysis was inhibited. Results indicate that plant extracts modified ruminal fermentation, but microbes were adapted to some extracts after 6 d of fermentation. Therefore, data from short-term in vitro fermentation studies may lead to erroneous conclusions, and should be interpreted with caution. Careful selection of these additives may allow the manipulation of protein degradation in the rumen.

Design, implementation and interpretation of in vitro batch culture experiments to assess enteric methane mitigation in ruminants—a review

“…However, this technique does not generate reliable information for agents that are only effective for decreasing CH 4 emissions over an extended period (Castro-Montoya et al, 2015). Furthermore, results from screening studies Durmic et al, 2010) are often inconclusive and may be conflicting due to variation in dosage, chemical structure of the test substance or compound, diet, combination of treatments applied, adaptation of rumen microbes or the form in which an agent is introduced into the system (Cardozo et al, 2004. Substantial decreases of CH 4 production in vitro (Tan et al, 2011) have been reported, but in several cases these have been accompanied by adverse effects on feed degradation, with the implication that a similar effect may occur in vivo which would compromise diet digestibility and animal performance.…”

Impacto de óleos essenciais de plantas brasileiras sobre parâmetros de fermentação ruminal, digestibilidade e balanço de nitrogênio em ovinos

“…Alterações semelhantes foram observadas para óleos essenciais de cinamaldeído, alho e anis, porém não avaliaram o efeito desses aditivos na proporção individual dos AGCC no rúmen. Cardozo et al (2004), ao trabalharem com óleo essencial de pimenta não encontraram efeito na concentração individual dos AGCC, somente para a concentração de valerato. Um efeito notável durante o período de adaptação foi observado para os óleos essenciais de cinamaldeído, alho, anis e orégano que afetaram a proporção molar de C2 e C3 e C4 entre os dias dois e seis de fermentação, não havendo diferença após o dia seis.…”

“…Estes resultados indicam que o extrato de cinamaldeído estimula a proteólise e inibe a peptidólise (CARDOZO et al, 2004).…”

“…Não foi observado interação tratamento vs dia para nenhum dos AGCC. Esta ausência de efeito pode ter sido devido as dosagens utilizadas no presente estudo, visto que os efeitos dos óleos essenciais nos parâmetros ruminais são dose dependente (CARDOZO et al, 2004 CTL= dieta controle negativo, sem adição de aditivos; MON = dieta controle positivo com adição de monensina sódica, 25 mg/kg de matéria natural; 1,09 = dieta com adição de 109 mL/100 Kg de MS de óleo essencial de Aroeira frutos (Schinus terebinthifolius); 2,18 = dieta com adição de 218 mL/100 Kg de MS de óleo essencial de Aroeira frutos (Schinus terebinthifolius); 3,27 = dieta com adição de 327 mL/100 Kg de MS de óleo essencial de Aroeira frutos (Schinus terebinthifolius). Os dados do presente estudo estão de acordo com Targer e Krause (2011) que trabalharam com três óleos essenciais (cinamaldeído, eugenol e capsicum), não encontrando efeito para pH ruminal (média 5,72).…”

“…Não foi observado interação tratamento vs dia para nenhum dos AGCC. Esta ausência de efeito pode ter sido devido as dosagens utilizadas no presente estudo, visto que os efeitos dos óleos essenciais nos parâmetros ruminais são dose dependente (CARDOZO et al, 2004 FRASER et al, 2007; WANG et al, 2009; YANG et al, 2010a,b;ANASSORI et al, 2011; GIANNENAS et al, 2011;KHOLIF et al, 2012;. …”