%0 Journal Article
%T Effect of different feeding strategies and dietary fiber levels on energy and protein retention in gestating sows.
%A Wisbech SJ
%A Nielsen TS
%A Bach Knudsen KE
%A Theil PK
%A Bruun TS
%J J Anim Sci
%V 102
%N 0
%D 2024 Jan 3
%M 38659196
%F 3.338
%R 10.1093/jas/skae092
%X The aim of the study was to investigate whether increased inclusion of sugar beet pulp (SBP) alters retention of fat, protein, and energy when backfat (BF) is restored in early- and mid-gestation. In total, 46 sows were fed one of four dietary treatments with increasing inclusion of SBP providing dietary fiber (DF) levels of 119, 152, 185, and 217 g/kg; sows were assigned to one of three feeding strategies (FS; high, medium, and low) depending on BF thickness at mating and again at day 30 for the following month. On days 0, 30, 60, and 108, body weight (BW) and BF thickness were measured and body pools of protein and fat were estimated using the deuterium oxide technique. On days 30 and 60, urine, feces, and blood samples were collected to quantify metabolites, energy, and nitrogen (N) balances. On days 15 and 45, heart rate was recorded to estimate heat energy. At farrowing, total born and weight of the litter were recorded. In early gestation, BW gain (P < 0.01) and body protein retention increased (P < 0.05) with increasing fiber inclusion, while body fat retention increased numerically by 59%. The increase in BF was greatest for sows fed the high FS, intermediate when fed the medium strategy, and negligible for sows fed the lowest FS (P < 0.001). Nitrogen intake, N loss in feces, and N balance increased linearly, whereas N loss in urine tended to decrease with increasing inclusion of fibers in early gestation. Concomitantly, fecal energy output and energy lost as methane increased linearly (P < 0.001), while energy output in urine declined linearly. Total metabolizable energy (ME) intake therefore increased from 36.5 MJ ME/d in the low fiber group to 38.5 MJ ME/d in the high fiber group (P < 0.01). Changing the ME towards more ketogenic energy was expected to favor fat retention rather than protein retention. However, due to increased intake of ME and increased N efficiency with increasing fiber inclusion, the sows gained more weight and protein with increasing fiber inclusion. In conclusion, increased feed intake improved both fat and protein retention, whereas increased DF intake increased protein retention.<BR>Feeding sows sugar beet pulp (SBP) has many known benefits, for example, increased satiety and high fermentability. This study investigates the ability of the sow to utilize energy for fat retention when replacing part of starch with dietary fiber. After a demanding lactation, sows need to restore body fat, and concomitantly avoid excessive protein retention, which will increase energy demand for maintenance and risk of locomotory problems. The hypothesis in this study is that energy from fermented fibers is more efficient for fat retention than dietary starch. In the study, sows had numerically greater fat retention when fed high concentrations of fiber from SBP, but concomitantly sows unintendedly also increased their protein retention, which in turn substantially increased their body weight. Sows were allocated to one of three feeding strategies depending on their body condition score (lean, medium, or fat) in early gestation, and backfat was efficiently restored in most sows within a month. In conclusion, although gestating sows have a high capability to utilize energy from fermentable fiber, they are disposed to protein over fat retention. These aspects need to be addressed in the nutrition of modern genotype sows.