Abstract To fully define the amino acid (AA) requirements of sows during early gestation, whole-body AA demands need to be characterized. This study aimed to characterize whole-body protein deposition and plasma AA profile from breeding to day 24 of gestation in seven sows in 2 consecutive parities. The same sows were bred following estrus synchronization approximately 53 days after weaning (Parity 5; 203 ± 7.4 kg; the ‘recovered’ parity) and bred 4-5 days after weaning (parity 6; 250 ± 5.5 kg; the ‘unrecovered’ parity). Sows were fed 1.80 kg once daily of a gestation diet (3158 ME kcal/kg; 0.54 % SID Lys; 0.3% titanium dioxide) in the ‘recovered’ and ‘unrecovered’ parities starting 5 days prior to breeding. After farrowing, litters were standardized to 14 piglets, and sows weaned 12.8 ± 1.5 piglets. Nitrogen (N) balance collections (fecal and total urine via bladder catheters) were completed at 3 time points (days: 1-3, 11-13, 21-24) in early gestation of both the ‘recovered’ and ‘unrecovered’ parity. Blood was collected in the morning before feeding at least once during each time point. Feed, urine, and feces were analyzed for N; N digestibility, N retention, and whole-body protein deposition (Pd) were calculated. Data was analyzed using PROC TTEST of SAS comparing ‘recovered’ sows with ‘unrecovered’ sows. The analyzed N intake was 30 g/d in the ‘recovered’ and 31.8 g/d in the ‘unrecovered’ due to differences in the analyzed N content of the respective diet batches. The total tract digestibility of dry matter (95.2 vs 95.1%) and the urine output (kg/d) were not different (P = 0.96) between the ‘recovered’ and the ‘unrecovered’ sows. Over the first 21 days of gestation, the ‘recovered’ sows had lower (P 0.01) N excreted in urine (22.2 vs 38.9 g/d) compared to the unrecovered sows, while there was no difference (P = 0.82) in N excreted in the feces (2.48 vs 2.58 g/d). Thus, the ‘recovered’ sows had positive N retention and Pd (5.21 and 32.5 g/d, respectively). The ‘recovered’ sows had greater (P 0.05) plasma concentration of LYS, MET, and HIS in the first 21 days of gestation compared to the ‘unrecovered’. The ‘unrecovered’ sows had negative N retention and Pd (-9.59 and -59.9 g/d, respectively). At the d1-3 time point, the ‘unrecovered’ sows had 82, 39, 35, 17, and 50 percent higher (P 0.01) concentration of VAL, PHE, ILE, LEU, and TRP, respectively, compared to ‘recovered’ sows. The difference in overall N metabolism in early gestation between ‘recovered’ and ‘unrecovered’ sows is likely reflective of mammary tissue involution. Specifically, the contribution of AA from mammary tissue involution in the first 21 days of gestation may need to be considered to appropriately characterize the dietary AA needs of the recently bred female.
Atoo et al. (Wed,) studied this question.