114 Late-Breaking: Gestation stage, lactation, and partial substitution of hydroxy minerals with methionine hydroxy analogue chelated minerals impacts nutrient retention.

Abstract The impact of stage of gestation, lactation, and trace mineral source on nutrient retention was evaluated using 16 parity 2 through 6 sows per treatment. Total fecal and urine collection periods were from days 40 to 44 and 96 to 100 of gestation. Lactation nutrient digestibility was determined using titanium dioxide as an inert marker. Gestating sows were fed once daily. Treatments provided 100 mg/kg of Zn, 20 mg/kg of Cu and 40 mg/kg of Mn either in the hydroxy (Selko®, Indianapolis, IN) form (ITM) or as a 50:50 blend of ITM and methionine-hydroxy-analogue-bis-chelate (NOVUS International Inc, Chesterfield, MO) form (MHAC:ITM). Diets contained 1,000 units/kg of phytase and 50 ng/kg of 25-OH-D3. Data normality was verified using Proc Univariate (SAS Inst. Inc., Cary, NC). Data were analyzed using the Proc Mixed procedure of SAS V9.4 with treatment as a fixed variable and block as a random variable. Analyzed gestation diet Zn, Cu, and Mn averaged 198, 35, and 88 mg/kg, respectively. Analyzed lactation diet Zn, Cu, and Mn were 121, 29, and 66 mg/kg, respectively. Late gestation tended to have greater ATTD of insoluble fiber (P < 0.10) and ash (P < 0.05) and greater retention of Ca, P (P < 0.05), and Na (P < 0.01) than early gestation. Retention of K was less (P < 0.01) in late vs. early gestation. Zn, Cu, and Fe retention tended to be greater (P < 0.01) in late vs. early gestation. Retention of Mn was unaffected by gestation stage. The ATTD of DM, N, GE, total and insoluble fiber, fat, ash, Ca, P, Mg, and Na were all less (P < 0.001) in lactation than gestation. Trace mineral program did not impact ATTD of DM, N, GE, or fiber (P >0.10). Fat digestibility tended to improve with MHAC:ITM in late (P < 0.10) but not early gestation. Retention of N was greater for the ITM treatment in early (P < 0.05) and late (P < 0.10) gestation. Retention of Ca and P was greater for MHAC:ITM in late gestation (P < 0.05). The mineral source did not affect early gestation trace mineral retention (P >0.10). Late gestation retention of Zn tended (P < 0.10) to be greater while Cu and Fe retention were greater for MHAC: ITM (P < 0.05). In lactation, Ca (P < 0.02), P (P < 0.01), and Mg (P < 0.01) ATTD were greater with MHAC:ITM. Lactation Zn loss was greater with MHAC:ITM (P < 0.001), while greater Cu loss was with ITM (P < 0.05). The ATTD of Mn was negative 10% for the MHAC:ITM treatment compared with a positive 3% for the ITM sows (P < 0.001). Results demonstrate greater mineral retention late gestation vs. other phases and greater late gestation mineral retention when Zn, Cu, and Mn are supplied in the MHAC:ITM blend.