Impact of feed additives in swine diets and the effect of corn particle size on metabolizable energy in gestating sows

Abstract

One experiment was conducted to evaluate the effect of formic acid and lignosulfonate addition on pellet quality. A second and third experiment were conducted to analyze the effect of 5 feed additives on PEDv and PRRSv in a feed matrix. A fourth study was conducted to analyze the effect of corn particle size on digestible and metabolizable energy in gestating sows. In experiment 1, 5 treatments consisting of a control, or the control with 2 levels of formic acid (0.36 % and 0.6%), or the control with a blended product containing 60% formic acid and 40% lignosulfonate (blended product was included at 0.6% and 1.0% of the diet). Diets were pelleted and analyzed pellet durability and hardness. Increasing formic acid in the diet decreased pH (P < 0.001). No evidence for differences (P > 0.05) were observed for pellet mill energy consumption, or pellet durability, regardless of testing method or pellet hardness when adding formic acid or lignosulfonate to the diet. In experiment 2, 12 chemical treatments 1) non-treated, individually inoculated virus controls (positive control), 2) 0.33% commercial formaldehyde-based product (Sal Curb; Kemin Industries, Inc.; Des Moines, IA), 3) 0.50% MCFA blend (1:1:1 ratio of C6:0, C8:0, and C10:0, Sigma Aldrich, St. Louis, MO), 4) 0.25%, 5) 0.50%, or 6) 1.00% of commercial dry mono and diglyceride-based product (Furst Strike; Furst-McNess Company, Freeport, IL), 7) 0.25%, 8) 0.50%, or 9) 1.00% of commercial dry mono and diglyceride-based product (Furst Protect; Furst-McNess Company, Freeport, IL), 10) 0.25%, 11) 0.50%, or 12) 1.00% dry mono and diglyceride-based experimental product (Furst-McNess Company, Freeport, IL). In total there were 12 treatments with 3 replications per treatment. A complete swine feed was treated with each chemical treatment before inoculation with 10⁶ TCID₅₀/g of feed with PEDV or PRRSV. PEDV or PRRSv RNA detection levels were then analyzed via quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR). Formaldehyde and MCFA decreased (P < 0.05) the detectable RNA concentration of PEDV and PRRSv compared to all other treatments. Furst Strike, Furst Protect, and the experimental product did not reduce detectable concentrations. In experiment 3, 4 chemical treatments were used 1) non-treated, individually inoculated virus controls (positive control), 2) 0.33% commercial formaldehyde-based product (Sal Curb; Kemin Industries, Inc.; Des Moines, IA), 3) 0.50% MCFA blend (1:1:1 ratio of C6:0, C8:0, and C10:0, Sigma Aldrich, St. Louis, MO). In total there were 4 treatments with 3 replications per treatment. A complete swine feed was treated with each chemical treatment before inoculation with 10⁶ TCID₅₀/g of feed with PEDV and PRRSv or a combination of the two. Sal Curb and MCFA both increased (P < 0.05) feed Ct values in the co-infection treatments for both viruses, whereas only Sal Curb increased Ct values when used against PRRSv (P < 0.05). The fourth and final experiment evaluated the effect of corn particle size on energy digestibility in gestating sows. Three particle sizes (400, 800, and 1200 μm) of corn were mixed into a complete gestation diet and fed to gestating sows (9 sows per treatment). Feed, feces, and urine were then analyzed for energy, nitrogen, and titanium dioxide levels to calculate digestible, metabolizable and nitrogen corrected metabolizable energy. Crude Protein, Digestible and Metabolizable energy (ME), nitrogen adjusted ME and Corn ME all increased (linear, P < 0.05) as particle size was reduced from 1200 to 400 μm.