Potential role of rumen microbiota in altering average daily gain and feed efficiency in meat goats fed simple and mixed pastures using bacterial tag-encoded FLX amplicon pyrosequencing

Authors: Min, Byeng Ryel; GURUNG, NAR - Tuskegee University; SHANGE, RAYMOND - Tuskegee University; SOLAIMAN, SANDRA - Tuskegee University

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/7/2019
Publication Date: 8/5/2019
Citation: Min, B., Gurung, N., Shange, R., Solaiman, S. 2019. Potential role of rumen microbiota in altering average daily gain and feed efficiency in meat goats fed simple and mixed pastures using bacterial tag-encoded FLX amplicon pyrosequencing. Journal of Animal Science. 97(8):3523-3534. https://doi.org/10.1093/jas/skz193.
DOI: https://doi.org/10.1093/jas/skz193

Interpretive Summary: Efficient meat production by cattle, goat and sheep are dependent on micro-organisms in the animal's first stomach called the rumen. However, there have been few studies to a potential role of rumen micro-organisms to enhance animal growth performance and feed efficiency in goats fed simple diets and mixed feed-pasture diets. Scientists from USDA-ARS (Bushland, TX) and Tuskegee University (Tuskegee, AL) studied how the rumen microbiome affects animal growth performance, rumen fermentation, microbial activities from grazing ruminants. The current results showed that increased body weight gain was associated with a specific type of bacteria. These data will be used to better understand feed efficiency and animal growth performance in goats.

Technical Abstract: Cost-effective and feasible production system of meat goats requires that grazed forages are converted to profitable goat meat product. However, there are studies as how altering forage type influences ruminal fermentation parameters and animal growth performance and interact with microbiota in meat goats. Our objective for current study was to examine whether the comparative abundance of the Bacteroidetes (B) and Firmicutes (F) bacterial phyla in meat goats fed simple and mixed forages influenced average daily gain (ADG) and rumen fermentation parameters. In the present study, a molecular approach, bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) was applied to accomplish diversity analyses of rumen bacterial populations. Thirty-six Kiko-cross growing meat goats (body weight (BW) = 27.7 ± 2.83 kg) at approximately 7 mo of age were used in this study. Animals were randomly allocated to three pasture treatment groups (n = 12) as follows: (1) bermudagrass pasture (BG; Cynodon dactylon), (2) sunn hemp forage (SH; Crotalaria juncea), and (3) BG + SH forage combinations. There were two replicates per treatment and animals grazed these pastures for 45-d. Results indicated that treatments had similar initial BW, but final BW and ADG were higher (P < 0.01) for SH and BG + SH combinations than for BG alone. Animal ADG and rumen fermentation (acetate to propionate; A/P ratios) were highly correlated with the abundance of various bacterial populations within the rumen microbiome. There were linear decreases in percentage of Bacteroidetes (R2 = -0.84; P < 0.05) associated with decreasing ADG. In contrast, increased ADG was linearly associated with higher percentages of Firmicutes (R2 = 0.79; P < 0.05), F/B ratios (R2 = 0.88; P = 0.07), total VFA (R2 = 0.45; P < 0.05), and lower A/P ratio (R2 = -0.72; P < 0.01). This suggests that the substrates (diets) and bacterial community have the role in adapting host biological parameters in meat goats. The abundance examination of both Bacteroidetes and Firmicutes will be useful for exploring the structure of gut microbiota as an estimate of animal performance.