Recipient Organization
MONTANA STATE UNIVERSITY
(N/A)
BOZEMAN,MT 59717
Performing Department
(N/A)
Non Technical Summary
Heavy metals are significant threats to human and animal health. Meat production animals, like cattle, can be exposed to heavy metals by ingesting contaminated feed and water. If exposures are high enough, animals fail to thrive, fail to gain weight, and are more susceptible to disease. Also, metals might enter the food chain in retail meat products and impact human health. Currently, there is little information regarding safe exposure levels for Ag animals. This project will generate this important information using controlled, experimental exposures in groups of beef cattle (steers). Groups of steers will be exposed to increasing doses of heavy metals and the lowest dose at which their liver and immune systems are affected will be identified. During these experiments, we will also determine whether meat and other retails products from these animals accumulate metals following exposure.Microorganisms living in the gut of cattle, called the "microbiome", help protect these animals from toxic effects of heavy metals and other contaminants. Bison and cattle have similar gut microbiomes and we know that bison living in Yellowstone National Park are naturally exposed to very high levels of metals in surface waters originating from hot springs and geysers. We think that bison drinking water with high levels of metals might host gut microorganisms with special abilities to detoxify toxic metals. If so, these microorganisms might help producers minimize the metal exposure in their herds and ultimately minimize metals in the food chain and human exposure. We will collected samples (stool and urine) from exposed and unexposed bison herds and identify microorganisms important for detoxifying heavy metals.
Animal Health Component
25%
Research Effort Categories
Basic
75%
Applied
25%
Developmental
0%
Goals / Objectives
The first objective of this project is to conduct experimental exposures in cattle to the top four metal toxicants threatening human health. In mammals, the gut microbiome helps detoxify metals, suggesting microbiome-focused therapies could mitigate spillover into the food chain. The second objective of this project is to identify the most efficient, potentially novel, metal detoxifying mechanisms among bovine gut microbes. We propose to evaluate the gut microbiome of bison (Bison bison) that overwinter in geothermal areas with high levels of toxic metals in Yellowstone National Park. An observational study is proposed to collect samples (feces and urine) from overwintering bison, identify metal tolerant/resistant microorganisms and statistically correlate their abundance with metal content in urine. Validation of metal detoxification activities will be performed by cloning enriched loci and performing in vitro bioassays. Stakeholders in the bison industry helped guide development of this project and are now collaboratively providing expertise and sampling opportunities. Results from this work will lead to improved risk assessment and provide key information for metal mitigation strategies by the gut microbiome.
Project Methods
Effort 1 - No observable adverse effect level (NOAEL) quantification. Groups of experimental stocker steers will be purchased and sourced from MSU farms. Groups will be exposed to escalating doses of the 4 most important metals to human health (arsenic, lead, mercury, and cadmium). Blood will be drawn from animals and analyzed for hallmark signs of toxicosis (e.g., liver enzymes and immune response). The lowest level at which cattle show signs of toxicosis to each metal will be reported.Effort 2 - Animals exposed to NOAEL for each metal will be euthanized and metals will be quantified in typical retail products. These experiments will be repeated at higher doses to help quantify risk of metals entering the food chain via beef exposed to higher levels of metals. Metals will be quantified using inductively coupled plasma mass spectrometry (ICP-MS).Effort 3 - Bison and beef cattle are important US meat production animals. Bison naturally inhabit areas with high toxic metals, which increases the likelihood of exposure. Metal exposure in bison will be compared between groups overwintering in high exposure (Yellowstone National Park) and low exposure (control herd at Flying D Ranch) areas. Metal exposures will be quantified by quantifying levels in stool and urine.Effort 4 - Microbiomes from high and low exposed bison will be evaluated for its ability to detoxify harmful metals using shotgun metagenomic sequencing.