نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکدۀ کشاورزی، دانشگاه بوعلی سینا، همدان، ایران
2 علوم دامی، دانشکدۀ کشاورزی، دانشگاه بوعلی سینا، همدان، ایران
3 هیئت علمی گروه علوم دامی دانشگاه بوعلی سینا همدان
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objectives: Given the escalating global population and its growing demand for animal protein resources, the significance of maximizing livestock production efficiency has doubled. Owing the low efficiency of rumen fermentation, the rumen manipulation has emerged as an effective strategy to improve feed efficiency and reduce nutrient wastage, thereby reducing environmental impact. In this context, the use of feed additives, particularly plant-derived secondary metabolites has attracted the attention of animal nutritionists as an effective strategy and sustainable solution in recent decades. Therefore, this study aimed to investigate in vitro the comparative effects of different levels of essential oil and extract of spearmint on gas volume production, rumen digestion parameters, and methane production.
Materials and Methods: The essential oil of spearmint (MSEO) was extracted by steam distillation method using a Clevenger apparatus, and its extract (MSEX) was obtained using 85% methanol followed by ultrasonic bath and centrifugation. In this study, the effects of spearmint essential oil and extract on rumen digestion and fermentation parameters of a high-concentrate diet for dairy cows were evaluated at six concentration levels: zero (as control), 150 (low dose), 300 and 450 (moderate doses), and 600 mg/L (high dose) and the treatment effects were analysed statistically using a complete randomised design with combined analysis.
Results: The volume of gas produced after 24 h of incubation changed quadratically (P< 0.01), and the percentage of methane production decreased linearly and non-linearly (linear and quadratic) with increasing dose of MSEO and MSEX, respectively (P< 0.01), as the high dose of MSEO and MSEX resulted in an 8.2% and 12.7% reduction in the percentage of methane production, respectively, compared to the control (P<0.01). The true in vitro dry matter and organic matter digestibility of the substrate decreased linearly with increasing dose of both MSEO and MSEX (P< 0.01). The microbial mass (MB) and efficiency of microbial biomass synthesis (EMBS) were affected only by MSEX, and increased non-linearly and linearly, respectively, with increasing dose of MSEX (P< 0.01),with the highest MB and EMBS (16.7% and 25.3% increase, respectively, compared to the control) observed at 450 and 600 mg/L of MSEX, respectively (P<0.01). Ammonia concentration increased and decreased linearly with increasing dose of the essential oil and extract of spearmint, respectively (P< 0.05), As at the high dose, MSEO increased ammonia by 46.5% while MSEX decreased ammonia by 13.6% compared to the control (P< 0.05). Total volatile fatty acid concentration decreased linearly with both MSEO and MSEX dosages (P< 0.01). The molar proportion of propionate increased non-linearly with both MSEO and MSEX dosages (P< 0.01), as the 150 mg/L level of MSEO and that of 600 mg/L of MSEX increased the proportion of propionate by 6.4% and 7.6% respectively compared to the control (P<0.01).
Conclusion: In conclusion, the results of this study showed that despite the negative effects of both MSEO and MSEX at high doses on rumen fermentation, the use of spearmint dry extract at low and moderate doses (equivalent to fairly 150 to 450 g/d for dairy cattles) could have have promising effects in improving rumen fermentation. The reduction in methane and ammonia production, and the improvement in microbial biomass and microbial biomass synthesis efficiency are indications of the beneficial effects of spearmint extract on rumen fermentation, which, in addition to improving production efficiency, may contribute to mitigating the environmental impact of ruminants, which requires further in vivo research under field conditions.
کلیدواژهها [English]
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