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After a demanding lactation period, sows need to restore body fat while avoiding excessive protein retention to prevent an increase in the maintenance energy demand and locomotory problems. Feeding sows sugar beet pulp (SBP) offers benefits such as increased satiety and high fermentability. This study aimed to investigate if an increased inclusion of SBP alters the retention of fat, protein, and energy during the restoration of backfat in early and mid-gestation.
Methods: In total, 46 sows were fed one of four dietary treatments with increasing SBP levels, providing dietary fiber at 119, 152, 185, and 217 g/kg. Sows were assigned to one of three feeding strategies (high, medium, low) based on backfat thickness at mating and reassessed at day 30. Body weight and backfat thickness were measured, and body pools of protein and fat were estimated using the deuterium oxide technique. Metabolites, energy, and nitrogen (N) balances were quantified from urine, faces, and blood samples collected on days 30 and 60. Heart rate was recorded on days 15 and 45 to estimate heat energy, and litter size and weight were recorded at farrowing.
Results: Results showed that in early gestation, body weight gain and body protein retention increased with higher fiber inclusion, while body fat retention increased numerically by 59%. Backfat gain was highest in sows fed the high fiber strategy, intermediate in the medium strategy, and negligible in the low strategy. Nitrogen intake, fecal N loss, and N balance increased linearly with fiber inclusion, while urinary N loss decreased. Fecal energy output and methane energy loss increased linearly while urinary energy output declined, resulting in higher metabolizable energy (ME) intake from 36.5 MJ ME/d in the low fiber group to 38.5 MJ ME/d in the high fiber group. Despite the expectation that more ketogenic energy would favor fat retention, increased ME intake and N efficiency led to greater weight and protein gain with higher fiber inclusion.
Conclusion: In conclusion, gestating sows can effectively utilize energy from fermentable fiber, improving fat and protein retention. However, increased dietary fiber intake predominantly enhanced protein retention, suggesting that dietary strategies need to be refined to optimize body composition in modern genotype sows.
Wisbech SJ, Nielsen TS, Bach Knudsen KE, Theil PK, Bruun TS. Effect of different feeding strategies and dietary fibre levels on energy and protein retention in gestating sows. Journal of Animal Science. 2024; 102: skae092. https://doi.org/10.1093/jas/skae092