PSI-17 Interactive Effects of Folic Acid and Zinc Oxide on Nursery Pig Growth Performance

Abstract

Abstract A total of 360 barrows (600×241, DNA; initially 5.5±0.029 kg) were used in a 38-d growth study to evaluate the effects of including increasing levels of folic acid (Rovimix Folic Acid, DSM, Parsippany, NJ) with or without pharmacological levels of Zn provided by zinc oxide (ZnO) on growth performance and fecal characteristics of nursery pigs. Pigs were weaned at approximately 19-d of age and randomly allotted to 1 of 6 dietary treatments. A total of 72 pens were used with 5 pigs/pen and 12 replications/treatment. Dietary treatments were arranged in a 3×2 factorial with main effects of folic acid (0, 20, or 40 mg/kg) and ZnO (3,000 mg/kg of Zn in phase 1 and 2,000 mg/kg in phase 2, or no added Zn other than 110 mg/kg from the trace mineral premix). Diets were corn-soybean meal based and fed in 2 phases. A common phase 3 diet with no folic acid and 110mg/kg of Zn was fed to all pigs. No significant (P > 0.10) folic acid×ZnO interactions were observed. For the experimental period (d 0 to 24), pigs fed diets with pharmacological levels of Zn had improved (P ≤ 0.030; Table 1) d 24 BW, ADG, and ADFI. There was a quadratic (P < 0.05) response for d 24 BW, ADG, and ADFI where pigs were fed 20 mg/kg folic acid had poorer performance compared with pigs fed 0 or 40 mg/kg. For the common period (d 24 to 38), pigs previously fed diets without pharmacological Zn had improved (P = 0.028) feed efficiency compared with pigs previously fed pharmacological levels of Zn. Additionally, a quadratic (P= 0.008) response was observed in ADG and ADFI when pigs were previously fed folic acid with pigs fed 20 mg/kg having poorer performance compared with pigs fed 0 or 40 mg/kg. Overall (d 0 to 38), there was a quadratic (P ≤ 0.003) response in final BW, ADG, and ADFI when pigs were fed folic acid with pigs fed 20 mg/kg having reduced performance compared with pigs fed 0 or 40 mg/kg; however, no overall differences (P > 0.10) were observed when pigs were fed diets with or without pharmacological levels of Zn in phase 1 and 2 diets. No statistical differences (P > 0.10) in mortality were observed when pigs were fed diets with or without pharmacological levels of Zn although pigs fed no supplemental folic acid had numerically the lowest mortality. Fecal DM percentage was greater (P = 0.007) on d 24 compared with d 9, with pigs fed diets with added Zn having reduced (P< 0.001) frequency of diarrhea presence. In conclusion, the addition of 40 mg/kg folic acid did not influence nursery pig performance, but a negative response was observed at 20 mg/kg, regardless of Zn inclusion in the diet.