Effects of Benzoic Acid and Enzyme Blend on Growth Performance, Nutrient Digestibility, and Diarrhea Incidence in Weaned Pigs

To facilitate the reduction in antibiotics used to manage post-weaning diarrhea (PWD), alternative dietary management strategies are required. Two such nutritional strategies, inclusion of benzoic acid and enzyme blend, were studied in weaned pigs (n = 200; 7.0 kg BW; Duroc × Large White/Landrace F₁). Diets fed were based on wheat, barley, soybean meal, and canola meal and were formulated without antibiotics to provide 5.3 g standardized ileal digestible (SID) Lys/Mcal NE that resulted in 22%-CP diets. At 7 d post-weaning, pigs were assigned in a randomized complete block design to be fed 5 diets for 21 d: positive control (Ctrl+; 2.37 Mcal NE/kg enriched with canola oil); negative control (Ctrl–; 2.27 Mcal NE/kg by reducing canola oil), and 3 diets that supplemented the Ctrl– diet with either 0.5% benzoic acid (BA), 0.045% enzyme blend (ENZ; phytase, β-glucanase, xylanase, and α-amylase), or both BA and ENZ (BAE). For the entire study, growth performance and apparent total tract digestibility (ATTD) of CP and GE did not differ between Ctrl– and Ctrl+ diets. The Ctrl– diet had lower (P<0.05) predicted NE value than Ctrl+ diet (2.41 vs. 2.52 Mcal/kg of DM). The ADG was greater (P<0.05) for the BA diet than for the Ctrl– diet (482 vs. 435 g). The BAE diet had greater (P < 0.05) ATTD of CP (79.6 vs. 82.4%), ATTD of GE (80.9 vs. 83.2%), and predicted NE value (2.56 vs. 2.41 Mcal/kg of DM) than the Ctrl‒ diet. In wk 2, diarrhea incidence [identified as a pen with at least 1 pig with diarrhea] was lower (P<0.05) for the BAE diet than for the Ctrl‒ diet (44.3 vs. 64.3%). Diarrhea incidence was affected (P<0.001) by week and was 40, 56, and 22 % for wk 1, 2, and 3, respectively. Ileal digesta pH was lower (P<0.05) for the ENZ diet than for the Ctrl‒ diet (6.27 vs. 6.76). In summary, BA increased ATTD of nutrients and BW gain. The BAE increased ATTD of nutrients and reduced incidence of PWD. In conclusion, supplementation of BA and /or ENZ might enhance nutrient utilization and reduce PWD thereby increasing growth performance in weaned pigs.