What question did this study set out to answer?

The aim is to evaluate how calcium gluconate supplementation affects hindgut microbiota and volatile fatty acids in steers.

April 4, 2026Open Access

Evaluation of the Hindgut Microbiota and Volatile Fatty Acid Profile of Steers Fed Finishing Feedlot Ration Supplemented with or Without Calcium Gluconate

Key Points

The aim is to evaluate how calcium gluconate supplementation affects hindgut microbiota and volatile fatty acids in steers.
20 Angus steers assigned to control and treatment groups based on weight.
Treatment group received 16 g/head/day of calcium gluconate for 55 days.
Digesta samples collected from the cecum, colon, and rectum at slaughter.
Microbial composition analyzed using 16S rRNA gene sequencing.
Data evaluated with a General Linear Model.
Increased acetate and propionate concentrations in the HFCG treatment group's digesta.
No difference in species richness between treatment groups.
Increased abundances of Erysipelotrichaceae and Peptostreptococcaceae in the cecal community of the HFCG group.
Elevated Ruminococcaceae and Muribaculaceae abundances in the colon microbiota of the HFCG group.
Changes in bacterial populations are important for gut health and fatty acid formation.

Abstract

Growing Angus steers (n = 20) were blocked by weight and randomly assigned to one of two treatment groups: Control group (CON, n = 10) fed a feedlot ration ad libitum, or a ruminally protected hydrogenated fat-embedded calcium gluconate (HFCG) treatment group (HFCG, n = 10), which was fed the control ration top-dressed at 16 g/head/day for 55 days. During the slaughter process, digesta samples were collected from the cecum, colon, and rectum. Acetate concentrations were greater in the cecal and rectal digesta of steers (p ≤ 0. 05) in the HFCG treatment group. Propionate concentrations were greater in the cecal, colonic, and rectal (p ≤ 0. 05) digesta of steers in the HFCG treatment group. Butyrate concentrations were greater (p = 0. 098) in the colon digesta of steers in the HFCG treatment group; however, they were not different in the cecal and rectal digesta. To determine the microbial composition within each section of the hindgut, DNA was extracted, and 16S rRNA gene sequencing was performed. Data were analyzed using a General Linear Model with dietary treatment as the main effect. Species richness in the cecum, colon, and rectum was not different between treatments. Erysipelotrichaceae, Peptostreptococcaceae, and Atopobiaceae abundances were increased (p ≤ 0. 05) in the cecal bacterial community of steers in the HFCG group, while a significant decrease (p ≤ 0. 05) in Rikenellaceae and Muribaculaceae abundances was recorded within the same bacterial community. In the colon bacterial community of steers in the HFCG group, Ruminococcaceae and Muribaculaceae abundances were elevated (p ≤ 0. 05), while there was a reduction (p ≤ 0. 05) in Lachnospiraceae, Erysipelotrichaceae, Atopobiaceae, and Peptostreptococcaceae abundances. Paeniclostridium, Romboutsia, and Turicibacter abundances were increased (p ≤ 0. 05) in the cecal bacterial community of steers in the HFCG group, while there was a decrease (p ≤ 0. 05) in RikenellaceaeRC9 gutgroup abundance within the same bacterial community. In the colon microbiota of steers in the HFCG group, Turicibacter abundance was decreased (p ≤ 0. 05). Supplementing growing steers with HFCG impacted some members of the bacterial populations, which have important roles in gut homeostasis and health, along with the formation of beneficial end-products in the gastrointestinal tract.

Evaluation of the Hindgut Microbiota and Volatile Fatty Acid Profile of Steers Fed Finishing Feedlot Ration Supplemented with or Without Calcium Gluconate

Key Points

Abstract

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