2007 Annual Report
1a.Objectives (from AD-416)
1) The identification and characterization of amino acid degrading microorganisms in the caprine rumen; and .
2)the development of a methodological platform from which to test products that inhibit amino acid degrading microbes or otherwise protect feed amino-nitrogen in meat goats.
1b.Approach (from AD-416)
Amino acid degrading bacteria will be enriched and isolated using roll tubes and agar plates in an anaerobic chamber in goats. The microbes found in greatest numbers will be enriched and isolated using roll tubes and agar plates in an anaerobic chamber. The phylogeny of the isolates will be determined by small ribosomal subunit DNA homology. The physiology of the isolates will be evaluated with hypothesis-driven experimentation. Particular attention will be given to the ability to degrade protein, catabolize amino acids, and persist in the rumen environment. The techniques will include, but not be limited to: spectrophotometry, enzymatic assays, gas and liquid chromatography, and sequencing pertinent genes (e.g. amino acid catabolic enzymes). Data will be interpreted in light of extant literature on the bovine model hyper-ammonia producing bacteria (HAB). Goats will be fitted with ruminal connulae for sampling, and the herd will be pastured (tall fescue, orchard grass, clover, sorghum-Sudan grass). Amino acid degrading bacteria will be enumerated in using serial dilution. Population counts will be compared to dietary nitrogen, urine/blood urea, and rumen ammonia. Weight gain, immunoglobulin levels, and parasite load will be monitored to ascertain animal health. Known counts of laboratory-grown bacteria will be added to the rumen, so the impact on amino acid degradation can be precisely measured. This later experiment will be conducted after the fashion of Kock's Postulates, which are a well-established method to determine the cause of an infection. Protocols to test feed additives and management practices will be developed based on the numbers, activities, and characteristics of the native microbial flora found in this study.
This report serves to document research conducted under a Specific Cooperative Agreement between ARS and the Kentucky State University. Additional details of research can be found in the report for the in-house project 6440-21310-001-00D, "Enhance Forage-Based Livestock Production Systems." Characterized hyper ammonia-producing bacteria are responsible for feed amino acid degradation in the bovine and ovine rumens, but few studies include goats. Moreover, many American meat goat ranchers use monensin to treat coccidiosis, but its effects on caprine rumen bacteria are undetermined. Five amino acid catabolizing isolates (all members of Family Peptostreptococcaceae) were obtained from the rumens of Boer goats, and the specific rates of amino acid deamination were >325 nmol mg cell protein-1 min-1. The results indicate that similar bacteria can occupy the hyper ammonia-producing guild in the bovine and caprine rumens. However, some of the caprine isolates have the ability to become monensin resistant, a trait that appears to be apomorphic among the Peptostreptococcaceae. This is the first report of Peptostreptococcaceae in the caprine rumen, and also the first report of monensin-resistant Peptostreptococcaceae in any environment. Studies such as this are required to develop a base of knowledge about the composition and physiology of caprine gastrointestinal microbiome, and to inform applied, field research.
Our scientist works closely with the collaborator on a regular basis concerning. Further, the scientist meets with the Research Leader at least bimonthly for a mentoring meeting and discusses progress with the Research Leader.