Supplementing a Clay Mineral-Based Feed Additive Modulated Fecal Microbiota Composition, Liver Health, and Lipid Serum Metabolome in Dairy Cows Fed Starch-Rich Diets

Abstract

Starch-rich diets are a commonly adopted strategy in order to sustain high milk yields in dairy cows. However, these diets are known to increase the risk of gut dysbiosis and related systemic health disorders. This study aimed to evaluate the effects of supplementing a clay mineral-based feed additive (CM; Mycofix® Plus, BIOMIN) on fecal microbiota structure, fecal short-chain fatty acid (SCFA) fermentation, serum metabolome, and liver health in primiparous (PP, n = 8) and multiparous (MP, n = 16) early-lactation Simmental cows (737 ± 90 kg of live body weight). Cows were randomly assigned to either a control or CM group (55 g per cow and day) and transitioned from a diet moderate in starch (26.3 ± 1.0%) to a high starch diet (32.0 ± 0.8%). Supplementation of CM reversed the decrease in bacterial diversity, richness, and evenness (p < 0.05) during high-starch diet, demonstrating that CM supplementation efficiently eased hindgut dysbiosis. The CM treatment reduced levels of Lactobacillus in PP cows during starch-rich feeding and elevated fecal pH, indicating a healthier hindgut milieu compared with that in control. Butyrate and propionate levels were modulated by CM supplementation, with butyrate being lower in CM-treated MP cows, whereas propionate was lower in MP but higher in PP cows. Supplementing CM during high-starch feeding increased the concentrations of the main primary bile salts and secondary bile acids in the serum and improved liver function in cows as indicated by reduced levels of glutamate dehydrogenase and γ-glutamyl-transferase, as well as higher serum albumin and triglyceride concentrations. These changes and those related to lipid serum metabolome were more pronounced in PP cows as also corroborated by relevance network analysis.

Keywords: dairy cattle; feed additive; hindgut microbiota; parity; systemic health.

Graphical Abstract

Figure 1

Effects of clay mineral (CM) × parity interaction on hindgut milieu parameters during moderate-grain feeding (M), followed by 4 weeks of high-grain feeding (H-wk1 to H-wk4). Dot plots illustrate fecal concentrations of (A) propionate, (B) butyrate, (C) isobutyrate, (D) valerate, (E) lactate, and (F) fecal pH. Control (CON) and treatment (CM) samples are show in blue and yellow, respectively. (*) indicates a difference by trend within parities (0.05 < p ≤ 0.10), and (**) indicates significant differences within parities (p ≤ 0.05).

Figure 2

Rarefaction curves indicating the number of operational taxonomic units (OTUs) during moderate-grain feeding (M), week 1 of high-grain feeding (H-wk1), and week 4 of high-grain feeding (H-wk4). Control (CON) and treatment (CM) samples are show in blue and yellow, respectively.

Figure 3

Alpha diversity indices. (A) Observed features, (B) Pielou's evenness index, (C) Shannon index, and (D) Faith's phylogenetic diversity of the fecal microbiota of early-lactation multiparous (MP) and primiparous (PP) cows during transition from moderate- to high-grain diets (after 1 and 4 weeks). (**) indicates differences between CON and CM in the same week (p ≤ 0.05). Control (CON) and treatment (CM) samples are show in blue and yellow, respectively.

Figure 4

Phylogenetic clustering of fecal microbiota based on principal coordinates analysis (PCoA) plots in regard to the weighted UniFrac distance matrix. Cows fed a 40% concentrate diet (M diet, red) followed by 4 weeks of a 60% concentrate diet (H diet week 1, blue; week 4, orange). Principal components (axis) 1, 2, and 3 indicate the % of variation explained between the samples.

Figure 5

Overall microbiota composition, given by the most abundant (A) phyla and (B) families.

Figure 6

Effect of CM supplementation in primiparous and multiparous cows fed a 40% concentrate diet for 1 week (M) and a 60% concentrate diet for 4 weeks (H-wk1 to H-wk4) on blood metabolites and liver health parameters. (A) triglycerides, (B) albumin, (C) GLDH, (D) GGT, (E) haptoglobin. **indicates significant differences within parities (p ≤ 0.05).

Figure 7

Relevance network analysis showing the most significant pairwise associations (A) between liver parameters and serum metabolome and (B) between fecal microbiota and fermentation profile impacted by feed additive feeding assessed using sparse partial least squares regression (|r| = 0.3).