Effects on mimosa tannin on the degradation of proteins in the rumen of cattle (Bos indicus)

Three studies were conducted to determine the role of Mimosa tannin in the rumen of grade cattle (Bos indicus) at UP Los Baños [College, Laguna, Philippines]. Study 1 was aimed at evaluating the effects of Mimosa tannin on the protein precipitation complex through radial diffusion assay (RDA) in legume tree leaves of Gliricidia (Gliricidia sepium)and Leucaena (Leucaena leucocephala). At 6% Mimosa tannin, the protein precipitation could be detected. In the second part of Study 1, addition of tannin to the pelletized Gliricidia at 6% allowed and not allowed to stand for 2 hr before pelletizing could not perform the ring binding in the RDA, hence the precipitation could not be detected. This result may be due to our heating during pelletizing and drying, causing the tannin content to be inactivated. Study 2 was aimed at determining the effects of Mimosa tannin on the solubility of protein in legume tree leaves. Four grade cattle with an average of 350 plus or minus 50 kg live weight, fitted with permanent rumen cannula, were used in study 2. Leaves of Leucaena and Gliricidia were macerated using mortar and pestle. Immediately after maceration, the Gliricidia was treated with Mimosa tannin at dosage of 0%, 3% and 6% on a DM [dry matter] basis, allowed to stand for 1 hr before oven-drying at 60 degC for 48 hrs. The dried samples were milled in a hammer mill before being inserted in the polyester bags with 5 g of each sample. The feed samples were preparedin duplicate and incubated for 6,12,24,48 and 72 hr. The results showed that increasing the time of incubation in the rumen ensures that more crude protein of feed is digested in the rumen and less in the intestines, where they should be. Addition of 6% Mimosa tannin to the macerated legume tree leaves protected DM digestibility and CP [ crude protein] digestibility of the feed in the rumen. Study 3 aimed at determining the effects of feed preparation on the protein so lubility of tannin-treated Gliricidia. Three grade cattle from the same group of animals in study 2 were used. The samples were inserted in the rumen cannula. The pellets consisted of 75% Gliricidia/Leucaena, 10% rice bran, and 15% molasses on a DM basis. Three percent of urea was added to the mixture on DM basis before pelletizing. Results showed that allowing the feed to stand for 2 hr before pelletizing gave a chance to the tannin to bind the mixture feeds, as a result, the solubility of the feed in the rumen can be reduced. Addition of urea to the feed generally reduced the amount of rumen undegradable protein or bypass protein, because non-protein nitrogen is readily degradable in the rumen.