Assessment of herbs and spices extracts/meal on rumen fermentation: a review

Abstract

The ban on antibiotics use in animal agriculture especially in Europe and the increased awareness of the consumers about the health hazards that occurs due to the use of antibiotics as feed additives in animal nutrition triggered a need for natural and safe feed additives such as plant extracts. Therefore, there is a need to explore/exploit different natural plant products to achieve better production in farm animals. Herbs and spices are known to have health benefits on animals when used as feed additives in animal nutrition. For effective use of herbs and spices, they can be added to feed as dried plants or as extracts. Ruminants have been adapted to fill an important ecological niche because of their specially adapted digestive tract that allows them to survive on fibrous feeds. However, the degradation of these feeds in the rumen leads to loss in terms of methane production and nitrogenous wastage. Methane loss represents about 12% of the gross energy of feed fed to the animals. Because of these reasons, there is need to manipulate the rumen microbial ecosystem for the purpose of improving ruminants production efficiency. Recently, many researchers have diverted their attentions to the use of extracts/meal from herbs and spices because of their great potentials. Many researches has been carried out by various researchers using different extracts/meal of some herbs and spices using in vitro gas production techniques to manipulate rumen microbial ecosystem in order to improve the productivity of ruminants. From the findings of these researches, it can be concluded that extracts of herbs and spices have a great potential in manipulating the process of rumen fermentation thereby reducing methane production, decreasing ammonium concentration and other rumen fermentation parameters.