The inclusion of organic acid to cereal feed improves growth performance in Pigs

The perspective ban on zinc oxide (ZnO) in pig feed in Europe is a major challenge facing the swine industry. The objective of this experiment was to compare the performance and health of post-weaned pigs fed either cereal (450g/kg wheat and 150g/kg barley) that was treated with an organic acid and salt blend (OA) at harvest time (4kg/tonne) or at diet manufacture (4 kg/tonne), with ZnO. The 144 pigs were assigned to one of 6 groups and fed for 35 days : (1) Dried cereal diet (DCD); (2) OA treated cereal diet at harvest (OATCD); (3) DCD+ZnO; (4) OATCD+ZnO; (5) DCD+OA at diet manufacture; (6) OATCD+OA (n=8 replicates/group). The dried and treated cereals were stored for 270 days before manufacture and dry matter content of the dried-wheat, treated-wheat, dried-barley and treated-barley was 14.2%, 16.7%, 14.6% and 16.4% respectively. The ZnO was included at 3300 ppm for 21 days and reduced to 1550 ppm thereafter. A faecal score (FS) system of 1- 5 was implemented to monitor the diarrhoea incidence (1=very hard,5=very loose). There was a cereal x additive interaction (P< 0.05) on daily gain (ADG) and daily intake (FI). The DCD + ZnO increased ADG (0.453 vs 0.404 vs 0.398, SE 0.024) and FI (0.725 vs 0.656 vs 0.630, SE 0.025) compared to DCD and DCD + OA diets. However, TCD + ZnO had no effect on ADG (0.405 vs 0.471 vs 0.462 , SE 0.025) and FI (0.674 vs 0.697 vs 0.742, SE 0.025) compared to TCD and TCD + OA diets. The ZnO reduced FS (2.074 vs 2.627 vs 2.716, SE 0.036) compared to the OA and non-additive diets. In conclusion, the addition of OA to cereals at harvest time is more beneficial to pig performance than at diet manufacture and gave growth performance similar to ZnO.