Effect of various medicinal plant essential oils obtained from semi-arid climate on rumen fermentation characteristics of a high forage diet using in vitro batch culture

Abstract

Eighteen natural medicinal plant essential oils and garlic oil obtained from semi-arid climate were conducted to evaluate their effects on in vitro rumen microbial fermentation and their effectiveness for decrease in vitro ruminal methane production. 50 ml of buffered rumen fluid (1:2; rumen fluid: buffer solution) were introduced in 125 ml serum bottles containing 500 mg of 80:20 alfalfa hay to concentrate as basal diet and or basal diet plus 1 µ/ml of medium of medicinal essential oils or garlic oil (6 replicates for each treatment) and incubated for 24 h at 38.7°C. Head space gas pressure of each bottle was recorded using a pressure transducer at 2, 4, 6, 8, 10, 12, 16 and 24 h of the incubation and a sample was collected to determine methane concentration. In the end of incubation pH measured and samples were collected for ammonia nitrogen concentration and dry matter (DM) and crude protein (CP) disappearance were recorded and feed fermentation efficiency (FFE = mg IDMD/ ml accumulative gas produced at 24 h post incubation) were calculated. Medicinal plant essential oils which caused an increase in FFE and decrease in gas production in-contrast with those in control were selected as the candidates for gas analysis and determine their effects on methane concentration. All essential oils resulted in a significant decrease (P < 0.05) in total gas production (except in Rosemary, Dill, Clove, Fennel, Pistachio hull and black pepper) and both IDMD and ICPD (except in Black pepper, Rosemary and Dill). Of the 19 samples tested coriander, rosemary, cinnamon, red basil, oregano 2, black pepper, cumin, caraway and dill that selected as the candidates for gas analysis and determine their effects on methane concentration increase in FFE and decrease in gas production in contrast with those in control. Increase in FFE was more noticeable for thyme, lemon pulp and cinnamon essential oils (22, 21.95 and 3.2 times more than those of control, respectively). Results indicated that coriander, cinnamon, red basil, oregano 2, cumin, caraway and dill essential oils caused a significant decrease (P < 0.05) in total methane production (1. 5, 0.3, 1.0, 1.3, 1.1, 1.1 and 2.0 compared with 2.3 in control as mmol/g DM incubated, respectively).

Effects of essential oils from medicinal plants acclimated to Benin on in vitro ruminal fermentation of Andropogon gayanus grass

“…Similar to the current experiment, it was observed that O. basilicum decreased DMD along with GP (DM incubated basis) of a 80:20 alfalfa hay:concentrate diet at 1000 mg L −1 . A previous report indicated that O. basilicum exhibited antimicrobial activity against a wide range of Gram‐positive and Gram‐negative bacteria due its high content of estragole, corroborating the reduction in digestibility observed in the present experiment.…”

“…Consistent with effects exhibited by C. aurantifolia in the present study, others reported that Citrus limon (1000 mg L −1 ), C. reticulata (333–1000 μL L −1 ) and C. sinensis (200–1200 mg L −1 ) contain chiefly limonene and decreased DMD and GP (DM incubated basis) from a range of dietary substrates . In an in vitro study, limonene was found to be responsible for the effects of C. reticulata on rumen microbial activity.…”

“…Jahani-Azizabadi et al 27 observed that O. basilicum (estragole type) inhibited methane production per g DM, in agreement with the current study. In contrast, this author also observed that O. basilicum decreased methane production per g DMD.…”

“…In contrast, DMD of ground alfalfa hay: concentrate at (50:50) and (80:20) were adversely affected by M. piperita (menthol type) when it was included at dosages of 500-1000 mg L −1 and 1 mL L −1 , respectively. 23,27 Consistent with effects exhibited by C. aurantifolia in the present study, others reported that Citrus limon (1000 mg L −1 ), C. reticulata (333-1000 L L −1 ) and C. sinensis (200-1200 mg L −1 ) contain chiefly limonene and decreased DMD and GP (DM incubated basis) from a range of dietary substrates. 24,25,27 In an in vitro study, 24 limonene was found to be responsible for the effects of C. reticulata on rumen microbial activity.…”

“…M. piperita is rich in menthol and menthone, and in agreement with our results, Patra and Yu observed negligible effects on DMD while GP (DM incubated basis) decreased from ground alfalfa hay:dairy concentrate (50:50) when it was included at 250 mg L −1 . In contrast, DMD of ground alfalfa hay: concentrate at (50:50) and (80:20) were adversely affected by M. piperita (menthol type) when it was included at dosages of 500–1000 mg L −1 and 1 mL L −1 , respectively …”