Effect of Dried Distillers Grains With Solubles and Red Osier Dogwood Extract on Fermentation Pattern and Microbial Profiles of a High-Grain Diet in an Artificial Rumen System

Walaa Mohamed Sayed Gomaa; Atef Mohamed Saleem; Tao Ran; Long Jin; Mohamed Samir; Emma J McGeough; Kim Ominski; Lingyun Chen; Wenzhu Yang

doi:10.3389/fvets.2021.644738

Effect of Dried Distillers Grains With Solubles and Red Osier Dogwood Extract on Fermentation Pattern and Microbial Profiles of a High-Grain Diet in an Artificial Rumen System

Front Vet Sci. 2021 Apr 9:8:644738. doi: 10.3389/fvets.2021.644738. eCollection 2021.

Authors

Walaa Mohamed Sayed Gomaa^{1

2}, Atef Mohamed Saleem³, Tao Ran⁴, Long Jin¹, Mohamed Samir⁵, Emma J McGeough⁶, Kim Ominski⁶, Lingyun Chen⁷, Wenzhu Yang¹

Affiliations

¹ Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada.
² Department of Animal Nutrition and Clinical Nutrition, Assiut University, Assiut, Egypt.
³ Department of Animal and Poultry Production, South Valley University, Qena, Egypt.
⁴ College of Pastoral Science and Technology, University of Lanzhou, Lanzhou, China.
⁵ Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt.
⁶ Department of Animal Science and National Centre for Livestock and the Environment, University of Manitoba, Winnipeg, MB, Canada.
⁷ Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.

Abstract

The objective of this study was to evaluate the effect of dried distillers grains with solubles (DDGS) and red-osier dogwood (ROD) extract on in vitro fermentation characteristics, nutrient disappearance, and microbial profiles using the rumen simulation technique. The experiment was a completely randomized design with a 2 × 2 factorial arrangement of treatments and four replicates per treatment. A basal diet [10% barley silage, 87% dry-rolled barley grain, and 3% vitamin and mineral supplement, dry matter (DM) basis] and a DDGS diet (as per basal diet with 25% of wheat DDGS replacing an equal portion of barley grain) were supplemented with ROD extract at 0 and 1% (DM basis), respectively. The experimental period was 17 d, consisting 10 days of adaptation and 7 days of data and sample collection. The substitution of wheat DDGS for barley grain did not affect gas production; disappearances of DM, organic matter, and crude protein; total volatile fatty acid (VFA) production; and microbial protein production. However, replacing barley grain with wheat DDGS increased (P = 0.01) fermenter pH and molar proportion of branched-chain VFA, switched (P = 0.06) the fermentation pattern to higher acetate production due to increased (P = 0.01) disappearance of neutral detergent fiber (NDF), and decreased (P = 0.08) methane (CH₄) production. In the basal barley diet, the ROD extract increased the acetate to propionate (A:P) ratio (P = 0.08) and reduced the disappearance of starch (P = 0.06) with no effect on any other variables. No effects of ROD in the DDGS diet were observed. The number of operational taxonomic unit (OTUs) and the Shannon diversity index of the microbial community had little variation among treatments. Taxonomic analysis revealed no effect of adding the ROD extract on the relative abundance of bacteria at the phylum level with either the basal diet or DDGS diet, while at the genus level, the microbial community was affected by the addition of both DDGS and the ROD extract. Prevotella and Fibrobacter were the most abundant genera in the basal diet; however, Treponema became the most abundant genus with the addition of the ROD extract. These results indicated that the substitution of wheat DDGS for barley grain may mitigate enteric CH₄ emissions. The trend of reduced starch fermentability and increased NDF disappearance with the addition of ROD extract suggests a reduced risk of rumen acidosis and an improvement in the utilization of fiber for cattle-fed high-grain diet.

Keywords: DDGS; RUSITEC; fermentation pattern; high grain diet; red osier dogwood extract.