Dietary L-arginine supplementation during late gestation in sows is associated with their backfat loss during lactation

The loss of backfat thickness in sows during lactation period is commonly observed in swine commercial herds under tropical climate. High backfat loss in lactating sows contribute to increase weaning-to-estrus interval. However, increasing the amount of feed during late gestation may cause high backfat thickness at farrowing, and lead to dystocia. Arginine is a precursor for nitric oxide synthesis, an important part for protein, fat and hormone synthesis. Arginine supplementation increases brown adipose tissue and protein synthesis in sows. The present study aims to investigate the effect of L-arginine supplementation in sow’s diet during late gestation on relative loss of backfat thickness of sows during lactation.

The study was carried out in a commercial swine herd in Thailand. Sows were allocated to four experimental groups: Group I (control), sows were fed a conventional gestation diet; Group II, sows were supplemented with 0.5% L-arginine; Group III, sows were supplemented with 1.0% L-arginine; and Group IV, sows were supplemented with 1.7% L-alanine. The feeding protocols were carried out from week 13 of gestation until farrowing. A total of 166 sows were included in this study. Sow’s backfat thickness was measured at the P2 level using A-mode ultrasonography at farrowing and at weaning. Backfat loss and relative loss of backfat (%) was calculated.

On average, the backfat thickness at farrowing were 14.5, 14.5, 13.9 and 15.9 mm in group I to IV, respectively. At weaning, backfat thickness of sows were 11.9, 12.6, 12.2 and 13.8 mm in Group I to IV, respectively. The backfat thickness at farrowing was positively correlated with the backfat loss and the relative backfat loss (r = 0.565 and 0.329, n = 160, respectively; P < 0.001). Arginine supplementation significantly influenced the relative backfat loss (P = 0.047). On the other hand, parity and interaction between group and parity did not influence the relative backfat loss (P > 0.05, respectively). The relative backfat loss in Group III sows (11.8%) was lower than Group I sows (16.9%, P = 0.019), but did not differ from Group II (12.6%, P > 0.05) and Group IV (13.5%, P > 0.05). On average, primiparous sows lost 14.0% of backfat and multiparous sows lost 13.5% of backfat during lactation period.

In conclusion, 1.0% L-arginine supplementation during late gestation is associated with a reduced relative backfat loss during lactation in sows.

Disclosure of Interest: M. Nuntapaitoon Conflict with: Research and researcher industrial Fund, R. Muns: None Declared, P. Tummaruk: None Declared.