Effects of combining increased lysine (protein) supply in late gestation and domperidone in lactation on sow and piglet performances

The aim of this project was to determine the impact of either increasing standardized ileal digestible (SID) Lys intake by 40% in gilts from days 85 to 111 of gestation, or combining that treatment with an increase in prolactin concentrations during lactation, on sow and piglet performances. On day 85 of gestation gilts were divided in three groups: (1) fed SID Lys at estimated NRC requirement (CTL, control, n = 23) until day 111 of gestation, (2) fed SID Lys at 40% above requirement via additional soybean meal (LYS, n = 22) until day 111 of gestation, or (3) fed SID Lys at 40% above requirement via additional soybean meal (LYSDOMP, n = 21) until day 111 of gestation and receiving domperidone throughout lactation. Experimental diets were isoenergetic. The LYSDOMP sows were injected daily with the dopamine receptor antagonist domperidone (0.5 mg/kg body weight, BW) from the day after farrowing until weaning. Additionally, they were fed 0.5 mg/kg BW of domperidone twice daily for the first 4 d of lactation. The CTL and LYS sows received injections and per os treatment with the vehicle. Litter size was standardized to 12 ± 1, and piglets were weighed on days 1, 7, and 22. Sow feed intake was recorded daily. Blood samples were collected on days 84 and 110 of gestation and days 1, 7, and 21 of lactation to measure prolactin, IGF-I, urea, free fatty acids (FFA), glucose (gestation only), and amino acids (gestation only). Milk samples were obtained on day 7 of lactation. Sow BW and backfat thickness throughout the study and feed intake in lactation were not affected by treatments (P > 0.10). Prolactin concentrations were greater for LYSDOMP compared with CTL and LYS sows on days 7 and 21 (P < 0.0001). Treatments did not alter IGF-I, glucose, or FFA concentrations at any time (P > 0.05), and urea was greater in LYS and LYSDOMP than CTL sows on day 110 of gestation (P < 0.05). Estimated milk yield or piglet growth rate was not affected by treatments (P > 0.10). In conclusion, feeding supplementary Lys (protein) in late gestation, either with or without domperidone in lactation, did not increase sow milk yield. Findings emphasize that a greater litter size was likely needed to see beneficial effects of supplementary Lys, and that the use of primiparous sows or inadequate lactational feed intake may have impeded the effects of the domperidone.