Deliverables
The ruminant is less efficient than other species in the utilization of dietary protein. Nitrogen losses from ruminants are exceptionally high, particularly in grazing animals. This is an environmental problem as well as an economic one, because of the impact of nitrogen-rich excreta on the environment. Improving the protein retention in the rumen could be done by the suppression of the population of rumen ciliate protozoa. Protozoa consume large quantities of bacteria in the rumen, their breakdown can result in a decrease of the net yield of microbial protein from rumen fermentation of up to 50%. If the protozoa could be suppressed, there would be less ammonia formation and less need for dietary protein supplementation.
The project results showed that this can be achieved by orally administering, suitably via the animal feed or the drinking water, an additive containing one or more components of plant materials selected from the group consisting of Lonicera japonica, Gentiana asclepidea, Gentiana lutea, Eugenia caryophyllata, Bellis perennis, Olea europaea, Symphytum officinale, Carduus pycnocephalus, Paeoniae alba radix, Populus tremula, Prunus avium, Salix caprea, Rheum nobile, Helianthemum canum, Arctostaphylos uva-ursi, Peltiphyllum peltatum, Epilobium montanum, Knautia arvensis, Latuca sativa and Urtica dioica and extracts thereof, and â-myrcene. The total amount of the components administered to an animal is suitably from 0.02mg to 20g per day and kg bodyweight.
Dietary protein entering the rumen is broken down in an apparently uncontrolled way, resulting in ammonia formation and subsequent loss of nitrogen in the urine. The low efficiency of nitrogen retention, which represents a major economic loss, causes metabolic stress in the animal, and also places a burden on the environment, by way of nitrogen-rich wastes. If the breakdown process could be decreased these problems would be decreased. Rumen-up studies have shown that the components of a subgroup consisting of plant materials from Helianthemum canum, Arctostaphylos uva-ursi, Epilobium montanum, Knautia arvensis and Peltiphyllum peltatum and extracts thereof, considerably reduce the ruminal proteolysis. In addition, all of these components inhibit the activity of protozoa and most of them have also beneficial influences on other essential fermentation parameters, such as the methane production, the amount of volatile fatty acids, the digestibility, the microbial biomass and/or the fermentation efficiency. The most suitable components are plant materials from Arctostaphylos uva-ursi, Knautia arvensis and Helianthemum canum and extracts thereof. Most preferred components are plant materials from Knautia arvensis and its extracts, especially methanol extracts.
Lactic acid is normally only a minor product of rumen fermentation. However, when a rapidly degraded feed is introduced too quickly, or when concentrates form a high proportion of the diet, volatile fatty acid production will exceed the buffering capacity of the rumen. This may lead to a so low pH value in the rumen that only lactic acid-producing bacteria can grow. As lactic acid is a stronger acid than the volatile fatty acids, pH falls even more, the recovery of the normal fermentation becomes impossible, and the animal dies.
More typically, however, ruminants on high-concentrate diets suffer sub-clinical acidosis, which is distressing and decreases production efficiency although not life-threatening. Chemical buffers can reverse this condition, but it would be better if the growth of the lactic acid-producing bacteria could be suppressed.
The project results showed that plant materials from Lactuca sativa and Urtica dioica and extracts thereof lower the activity and/or the formation of lactic acid. Lactuca sativa, sometimes called Lactuca virosa, also diminishes the methane production and the protozoal activities and increases the formation of volatile fatty acids. Urtica dioica has also additional effects and inhibits the proteolysis and protozoal activities and favours the formation of volatile fatty acids.
Plant materials from Carduus pycnocephalus, Paeoniae alba radix, Populus tremula, Prunus avium, Salix caprea, and Rheum nobile and extracts thereof form a group, components of which are suitably used to decrease the methanogenic activity in the rumen digesta. For these components no important detrimental effects have been observed on other fermentation parameters. Preferred components are the plant materials from Carduus pycnocephalus, Populus tremula, and Rheum nobile and extracts thereof, especially preferred are Carduus pycnocephalus and Rheum nobile. These plants have the potential to decrease methane emissions, and thus to decrease greenhouse gas emissions, as methane is a potent greenhouse gas.
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