Ground redberry juniper and urea in DDGS-based supplements do not adversely affect ewe lamb rumen microbial communities

Abstract Text:

Effects of using ground redberry juniper and urea in dried distillers grains with solubles (DDGS)-based supplements fed to Rambouillet ewe lambs (n = 48; 42 kg ± 3.8) on ruminal parameters and microbial communities were evaluated. In a randomized design study (40 d), individually-penned lambs were fed ad libitum, a basal diet of ground sorghum-sudangrass hay and of 1 of 8 supplements (6 lambs/treatment; 496 g/d; DM basis) in a 4 × 2 factorial arrangement with 4 concentrations of ground juniper (15, 30, 45, or 60% of DM) and 2 levels of urea (1 or 3% of DM). Growth performance, serum and fecal characteristics were reported. Ruminal fluid was collected via oral lavage at the end of the trial (d 34). Total VFA was unchanged (P > 0.51) with supplements. As a percentage of total VFA, propionic was similar (P = 0.34), acetic acid increased (P = 0.004) and butyric acid decreased (P = 0.03) as concentration of juniper increased in the supplement; urea did not have an effect (P > 0.10). Ammonia N was not affected (P > 0.12), but ruminal pH increased (P < 0.001) with juniper concentration; not with urea (P > 0.89). Treatment (individual juniper or urea concentrations, or juniper × urea) effects on operational taxonomic unit (OTU) abundance were not significant using ANOSIM (P > 0.05), AMOVA (P > 0.01), or PERMANOVA (P > 0.05). Treatments did not produce significantly different phylogenetic trees by structure (P> 0.05, unweighted UniFrac), but did produce some small, yet significant pairwise comparisons by abundance (weighted UniFrac). Samples did not significantly cluster by diet or supplements using metric multi-dimensional scaling plots. Families Prevotellaceae and BS11 gut group (Bacteroidetes) decreased with increasing concentrations of both juniper and urea, while families Acidaminococcaceae and S24-7 increased. Christensenellaceae and Lachnospiraceae increased with juniper concentration at a 1% urea. High concentrations of juniper were associated with Moraxella and Streptococcus, low concentrations of urea were associated with Fretibacterium, and high concentrations of urea were associated with Oribacterium and Pyramidobacter. In conclusion, on a low-quality basal hay diet, ewe lamb ruminal parameters can be attributed to differences in the concentrate:forage ratio, fiber, degradable N, and secondary compounds. Despite some differences in bacterial diversity between treatments, due to changes in volatile fatty acid profile, ammonium, and pH, there was not a significant difference in OTU presence or abundance.

Keywords: lambs, supplement, bacterial diversity