The effect of benzoic acid with or without a direct-fed microbial on the nutrient metabolism and gas emissions of growing pigs

Authors: HUMPHREY, DALTON - Iowa State University; BERGSTROM, JON - Dsm Nutritional Products, Ltd; CALVO-PEREZ, ESTEFANIA - Dsm Nutritional Products, Ltd; Trabue, Steven - Steve; Scoggin, Kenwood; GREINER, LAURA - Iowa State University

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2022
Publication Date: 9/3/2022
Citation: Humphrey, D.C., Bergstrom, J.R., Pérez Calvo, E., Trabue, S.L., Scoggin, K.D., Greiner, L.L. 2022. The effect of benzoic acid with or without a direct-fed microbial on the nutrient metabolism and gas emissions of growing pigs. Journal of Animal Science. https://doi.org/10.1093/jas/skac296.
DOI: https://doi.org/10.1093/jas/skac296

Interpretive Summary: Diet formulations to improve both economic and environmental efficiency. Diet formulations can be design to lower emission and more efficiently nutrients. The use of non-nutritive feed additives (compounds that enhance growth) and probiotics (microorganism that improve growth) can be used to improve the efficiency of nutrient utilization in pigs. ARS researcher in Ames, Iowa, in collaboration with an Iowa State University researcher, conducted a swine feeding trial to evaluate the effects of supplementing benzoic acid, a growth promoting compound, with and without probiotic cultures had on the nutrient utilization and emissions of growing pigs. Feeding 0.3% benzoic acid did not affect nutrient digestibility, but reduced N excretion, and improved N retention compared to the standard diet. Benzoic acid in diets reduced urine and manure pH stabilizing NH3 in manure reducing emissions. However, supplementing with microorgamisms had no effect and when supplemented with benzoic acid weakened its positive effects. Information from this research will be of value to researchers, feed companies and growers looking for alternative feed ingredients to improve the environmental sustainability of swine production.

Technical Abstract: Twenty-four gilts (PIC 337X1050, PIC Genus, Hendersonville, TN) with an initial body weight (BW) of 33.09±1.33 kg were used to investigate the effects of benzoic acid (BA) with or without a Bacillus-based direct-fed microbial (DFM) on the nutrient metabolism and emissions of growing pigs. Pigs were blocked by BW, placed into metabolism stalls, and randomly assigned to one of four dietary treatments: basal control (PC), low nitrogen (NC), PC plus 0.3% BA (VevoVitall, DSM Nutritional Products), and PC plus 0.3% BA and 0.025% DFM (PureGro, DSM Nutritional Products). Pigs were fed a common diet from d 0 to 14, and the experimental diets were fed in two phases (d 14 – 28 and d 28 – 53). The experiment consisted of four collection periods, with each period subdivided into two sub-periods to measure gas emissions and nutrient balance. Pigs were weighed at the beginning of the experiment and at the end of each collection period. Gas emissions sub-periods lasted 72 hours. Twice daily, urine and feces were weighed, and urine pH was measured. After each period, manure was subsampled and taken to the lab to measure ammonia, hydrogen sulfide, carbon dioxide, and methane emissions. Urine and feces were quantitatively collected for 96 hours to measure nutrient digestibility (ATTD) and retention. Data were analyzed as repeated measures in SAS 9.4 (SAS Inst., Cary, NC) with fixed effects of treatment, collection period, and block. Pig was the experimental unit, and results were significant at P = 0.05. Pigs fed BA had the greatest ADG (922 g d-1) compared to pigs fed NC (849 g d-1), with intermediate ADG for pigs fed PC (882 g d-1) or BA+DFM (906 g d-1). The ATTD of dry matter, gross energy, phosphorus, and nitrogen did not differ between treatments (P = 0.093). However, the ATTD of calcium was reduced in pigs fed BA+DFM compared to pigs fed BA (60.97 vs. 69.20%; P = 0.012). Pigs fed BA or NC excreted less nitrogen in urine compared to PC and BA+DFM (P = 0.034), which contributed to greater nitrogen retention in BA compared to PC (66.46 vs. 60.67%; P = 0.016). Furthermore, decreased manure pH from pigs fed BA or NC resulted in lower NH3 emissions compared to pigs fed BA+DFM or PC. There was no effect of dietary treatment on manure H2S, CH4, or CO2 emissions. In conclusion, supplementing 0.3% benzoic acid improved nitrogen retention and reduced manure pH and ammonia, similarly to feeding pigs low protein, but improved the ADG of pigs when compared to feeding a low protein diet.