Impact of narasin on manure composition and microbial ecology, and gas emissions from finishing pigs fed either a corn-soybean meal or a corn-soybean meal-dried distillers grains with solubles diets

Authors: Kerr, Brian; Trabue, Steven - Steve; VAN WEELDEN, MARK - Iowa State University; ANDERSEN, DANIEL - Iowa State University; PEPPLE, LAURA - Puck Custom Enterprises, Inc

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2018
Publication Date: 1/1/2018
Citation: Kerr, B.J., Trabue, S.L., van Weelden, M., Andersen, D., Pepple, L. 2018. Impact of narasin on manure composition and microbial ecology, and gas emissions from finishing pigs fed either a corn-soybean meal or a corn-soybean meal-dried distillers grains with solubles diets. Journal of Animal Science. 96:1317-1329. https://doi.org/10.1093/jas/sky053.
DOI: https://doi.org/10.1093/jas/sky053

Interpretive Summary: Lipophilic ionophores allow for attachment to cell membranes of bacteria, with a higher affinity towards Gram-positive bacteria, fungi, and coccidia than towards Gram-negative bacteria. Past studies have shown that feeding ionophores may improve pig growth performance, but has little impact on energy and nutrient digestibility, especially in finishing pigs. There are also data to suggest that ionophores may affect manure microbial ecology which could therefore affect manure composition and gas emissions. The current study was conducted to determine the impact of narasin supplementation to finishing pigs fed either corn-soybean meal or diets containing distillers dried grains, on subsequent manure composition, manure gas emissions, and manure microbial ecology. In general, data from this experiment indicate that feeding finishing pigs a diet which contains an elevated level of indigestible fiber resulted in more fiber in the manure which therefore dramatically affected manure composition, gas emissions, and microbial ecology, while narasin supplementation to the diet did not exhibit a significant effect on any of these parameters in the resultant swine manure. This information is important for nutritionists at universities, feed companies, and pig production facilities for determining the effect of feeding different diets (low or high fiber) or the ability of an ionophore to affect manure composition and gas emissions from manure storage facilities, each of which provides a basis from which to assess a diet's environmental impact and economic value.

Technical Abstract: An experiment was conducted to determine the effect of feeding finishing pigs either a corn-soybean (CSBM) diet or a CSBM diet supplemented with 30.34% distillers dried grains with solubles (DDGS), in combination with either 0 or 30 mg narasin/kg of diet, on subsequent manure composition, manure microbial ecology, and manure gas emissions. Two separate groups of 24 gilts (initial BW = 145.1 kg, SD = 7.8 kg) were allotted to individual metabolism crates that allowed for total but separate collection of feces and urine during the 48-d collection period. After each of the twice-daily feedings, feces and urine from each crate was collected and added to its assigned enclosed manure storage container. Each container contained an individual fan system that pulled a constant stream of air over the manure surface for 2 wk prior to air (d 52) and manure sampling (d 53). After manure sampling, the manure in the tanks was dumped and the tanks cleaned for the second group of pigs. Except for total manure Ca and P output as a percent of intake and for manure methane product rate and biochemical methane potential (P = 0.08), there were no interactions between diet composition and narasin supplementation. Narasin supplementation resulted in increased manure C (P = 0.05), increased manure DM, C, S Ca, and phosphorus as a percent of animal intake (P = 0.07), and increased manure volatile solids and foaming capacity (P = 0.09). No effect of narasin supplementation was noted on manure VFA concentrations or any of the gas emission parameters measured (P = 0.29). In contrast, feeding finishing pigs a diet containing DDGS dramatically affected manure composition as indicated by increased concentration of DM, C, ammonia, N, and total and volatile solids (P = 0.01), increased manure DM, N, and C as a percent of animal intake (P = 0.01), increased manure total VFA and phenols (P = 0.05), increased gas emissions of ammonia, volatile sulfur compounds, phenols, and indoles (P = 0.06), increased methane production rate (P = 0.01), and slight differences in microbial ecology (R = 0.47). In conclusion, feeding finishing pigs a diet which contains an elevated level of indigestible fiber resulted in more fiber in the manure which therefore dramatically affected manure composition, gas emissions, and microbial ecology, while narasin supplementation to the diet did not exhibit a significant effect on any of these parameters in the resultant swine manure.