Mammary nutrient uptake in sows fed supplementary dietary fiber and fat during lactation

Dietary fiber (DF) and fat, as precursors of ketogenic energy substrates, are hypothesized to enhance de novo milk fat synthesis and thereby increase milk yield in lactating sows. This study aimed to evaluate the effects of high DF and fat supplementation during lactation on mammary nutrient uptake, milk production, and growth performance of the piglets. Ten cross-bred gestating sows (Danish Landrace × Danish Yorkshire; initial average body weight: 276.00 ± 17.53 kg, mean ± SD; parity: 3 to 5, with a distribution of 4, 4, and 2 sows at parities 3, 4, and 5, respectively) were selected and assigned to either a control diet (Con; n = 5) or a high fiber and fat supplemented diet (FF; n = 5) from day 5 of lactation until weaning on day 28 of lactation. Sows were surgically fitted with two indwelling catheters in the mammary vein and one in the femoral artery on day 75 ± 2 of gestation. A blood flow marker was infused into one of the mammary veins at a rate of 3.0 mmol/h, and eight blood samples were collected at hourly intervals on day 7 and day 17 of lactation, respectively. One sow from the Con and two sows from the FF group had low feed intake (