Nutrient absorption in two Bison bison herds on the Fort Peck Indian Reservation
Authors: Sun Rhodes Ryon , War Club Crystal , Rajendran Vazhaikkurichi M. , Topcliff Christina L. , Kelling Clayton L. , Coon Steven D. 
Published: May 2022

On the Fort Peck Reservation bison are separated into two pastures: a genetically pure bison herd (cultural herd) and a non‐genetically pure bison herd with cattle genes (business herd). Vital nutrients may be lacking in their diet, nutrients may not be absorbed or resident parasitic infections may block absorption. We are measuring the absorption of key nutrients such as short chain fatty acids (SCFA), glucose and essential trace metals. Ussing chamber studies ussing stomach tissue measure the absorption of some nutrients. Trace metals of copper and zinc are stored in the liver and measurements of those levels will determine deficiencies in the animals. It is also assumed that the same parasites that afflict cattle also populate bison. In addition, ruminants such as the bison rely on microbiota for proper digestion and absorption of SCFA and also require many of the same vital trace metals. Bison possess flaps of tissue that increase the surface area of the stomach compartments suggesting that nutrients are probably absorbed there but no studies have been performed to investigate this possibility. Plant materials were removed from the stomach compartments for future microbiota analysis. Fecal material has also been removed from the intestine and colon for microbiota comparison purposes comparing metal deficient animals with nourished animals. Tissue samples and fecal material from the two herds were removed and stored at 4˚ C for a week, and were analyzed for ova with Sheather’s Sugar Flotation Solution with a compound microscope. The remaining samples were stored for other experiments at 4˚ C. Results show higher infestation rates in the cultural herd than the business herd (0.4‐7.78 ova/gram for Strongyle, 0.4 ova/gram for Trichuris, 0.2‐0.67 ova/gram, and 0.6 ova/gram for Coccidia, versus the business herd which had no infestations). Next, we analyzed tract metal levels in liver samples between the two herds with mass spectroscopy. Essential trace metals were quantitatively shown to be deficient among the two herds. Copper levels were substantially lower at 7.8± 0.5 ppm for the cultural herd and 6.7±0.8) and for the business herd (normal levels are 87.5±16). Zinc values are also substantially lower at 30.57±0.5 for the cultural herd and 25± 2.6 for the business herd. (normal levels are 112.5± 12) Ussing Chamber experiments were performed on the reticulum (1st stomach) tissues of both cultural and business herds, with results in sodium‐glucose co‐transport in the first stomach of each of the twelve animals. Initial analysis of short circuit current (Isc) indicates glucose absorption (1.99±0.13 µAmp) and SCFA absorption (butyrate, 2.24±0.24 µAmp/ cm2) and however no differences seem to exist between the two herds. These studies suggest that there is a reduction of some nutrients such copper and zinc in bison that other nutrients such a glucose and SCFAs absorption does occur in the first stomach. Ova levels of the various herds is too low to have a significant effect on absorption of nutrients.