A two-component feeding strategy with high supply of energy and lysine ensured a high milk yield, minimal mobilization and improved feed efficiency of lactating sows1

Abstract This study investigated the impact of energy supply and dietary lysine concentration on body reserve mobilization pattern, milk yield, nutrient balances and feed efficiency of sows fed 1 of 4 different dietary treatments. Two dietary components were formulated to meet the requirement for maintenance (basal; low in lysine) and milk production (lactation; high in lysine). A total of 24 second-parity lactating sows were assigned to the dietary treatments using 2-component feeding strategies. Sows were supplied either high (HE) or low (LE) energy (i.e. two feeding levels), and within each feeding level, sows were supplied with high (HL) or low (LL) dietary lysine concentration from their total ration. The four dietary strategies, HEHL, HELL, LEHL, and LELL, were obtained by supplying different amounts and ratios of the basal and the lactation components. The dietary strategies were defined to generate distinct mobilization patterns in the four groups, i.e mainly muscle mobilization (HELL), mainly fat mobilization (LEHL), muscle + fat mobilization (LELL), or no mobilization (HEHL). Sows and piglets were weighed on d 2, 7, 14, 21, and 28 of lactation and milk samples were collected weekly. Sows were enriched with deuterium oxide on d 3 and 28 of lactation to estimate body mobilization. Sows fed LEHL and LELL strategies lost greater BW (P = 0.005), mobilized greater body protein (P = 0.001) and body fat (P = 0.01) than HEHL or HELL fed sows. Sows fed HEHL and LELL (12.9 kg/d) had greater milk yield than sows fed LEHL (11.6 kg/d) with HELL fed sows being intermediate (12.7 kg/d; P = 0.04). Negative energy balances and mobilization of body fat and protein were observed for all 4 dietary strategies to various extent, indicating that sow mobilization pattern is rather complex. The study revealed that high BW loss and high body reserve mobilization are not necessary to achieve a high milk yield when dietary supply of nutrients were optimized according to the requirements. Feed efficiency, evaluated as net energy corrected for mobilization of body reserves, was greater in HEHL and HELL strategies (P