Feasibility for Bioconversion of Slaughterhouse Rumen Contents to Bioprotein Supplement by Yeast for Feeding of Livestock Animals

Rumen contents are containing relatively digested and undigested foods, that in case of processing is re-feed the animals. In this project, the rumen contents for dehydration was mixed with 20% typical straw and were sprayed with concentrated sulfuric acid (at a ratio of 1.5% by weight) for acid hydrolysis, then three percent molasses + three percent solution of ammonia was added as silage additives for enrichment and ensiled in polyethylene barrels for 21 to 30 days. After ensiling time, the silage was assessed from quality and appearance parameters and required samples were taken for microbial tests. At this stage the silage were used as a substrate (pasteurized and unpasteurized) for yeast culture. For conducting of them project in two forms rumen contents (pasteurized and unpasteurized) were inoculated with three levels (1.5, 3 and 4.5 percent by weight) of a suspension containing at least cellulose degrading yeast 3×109 cfu and incubated at temperature 28-30°C for three to four days (72-96 hours). At the end of each stage, the final product were measured from chemical composition and invitro digestibility. This project was carried out by factorial 2×3 in completely randomized design (CRD) with 6 treatments and 4 replications. The results showed that due to the low pH in the test samples by acid hydrolysis and also due to high levels of propionic acid in the rumen contents, the used yeast in experimental treatments could not have significant growth and proliferation, and the amount of microbial biomass production did not come out as expected. So the most economical method, is recommended ensiling of rumen contents after dehydration and acid hydrolysis with 1.5 percent and enrichment by biochemical method with molasses and ammonia.