Feeding distillers dried grains with solubles and organic trace mineral sources to swine and the resulting effect on gaseous emissions1

Abstract

The objective of the study was to evaluate the dietary effects of distillers dried grains with solubles (DDGS) with either inorganic or organic trace mineral sources on air emissions. Three diets were compared: a corn- and soybean meal-based control diet (Con), a diet containing 20% DDGS with inorganic trace mineral sources (20In), and a diet containing 20% DDGS with organic trace mineral sources (20Org). Groups of 6 pigs were allocated randomly to 1 of 12 environmentally controlled rooms for a 98-d experiment. A total of 72 pigs were blocked into 3 light and 3 heavy BW groups to minimize BW variation. Average initial BW for the light and heavy blocks were 22.6 kg and 27.0 kg, respectively. Concentrations and airflow of NH₃, H₂S, N₂O, CH(4), CO₂, and nonmethane total hydrocarbons (NMTHC) were measured in the exhaust air from each room. Body weight gain (94 kg per pig; P = 0.36) and G:F (0.39; P = 0.79) were not different as a result of diet, although a reduced feed intake was observed in pigs offered 20Org (P < 0.05). Total daily H₂S emission mass was greater (P = 0.03) in rooms where the 20In diet was offered (462.26 mg) compared with rooms where the Con (354.62 mg) and 20Org (323.10 mg) diets were offered. No dietary effect (P = 0.47) was observed when H₂S emissions were adjusted for S consumption (14.38 mg of H₂S emitted daily per gram of S consumed). Compared with NH₃ emitted on the Con diet, the daily mass of NH₃ emitted decreased by 7.6% when pigs were fed 20In and increased by 11.0% in rooms where the 20Org was fed (P < 0.05). On a N consumption basis, feeding swine 20In significantly reduced NH₃ emissions compared with 20Org and Con, whereas NH₃ emissions from pigs fed 20Org were significantly greater than emissions from pigs fed the Con diet (P < 0.01). The NH₃ emission mass from rooms offered the Con, 20In, and 20Org diets was 120.1, 109.8, and 142.8 mg/g of N consumed/d, respectively (P < 0.01). Feeding DDGS with either inorganic or organic trace mineral sources increased the daily emission masses of CH₄ and NMTHC (P < 0.01), but not N₂O emissions. Plasma urea N (P = 0.64), albumin (P = 0.39), globulin (P = 0.75), and total bilirubin concentrations (P = 0.82) were not different between diet groups. Results demonstrated that DDGS will increase H₂S, CH₄, NH₃, and NMTHC emissions from pigs, but organic sources of trace minerals are a promising mitigation strategy to alleviate the adverse effect of DDGS on H₂S emissions.