Effects of dietary threonine:lysine ratioes and sanitary conditions on performance, plasma urea nitrogen, plasma-free threonine and lysine of weaned pigs

• Main Authors: Balachandar Jayaraman, John Htoo, Charles Martin Nyachoti
• Format: Article
• Language: English
• Published: KeAi Communications Co., Ltd. 2015-12-01
• Series: Animal Nutrition
• Subjects: Threonine:lysine ratio; Sanitation; Weaned pigs; Growth performance
• Online Access: http://www.sciencedirect.com/science/article/pii/S2405654515300378

Two 21 d-experiments were conducted to determine the optimum standardized ileal digestible (SID) threonine:lysine ratio (Thr:Lys) for weaned piglets reared under clean (Exp. 1) or unclean (Exp. 2) sanitary conditions and fed antibiotic-free diets. In each experiment, 90 mixed-sex pigs (Duroc × [Yorkshire × Landrace]; initial BW 7.2 ± 0.3 kg) were randomly assigned to 5 dietary treatments each with 6 replicates (3 pigs per pen). The dietary treatments were 5 graded levels of SID Thr:Lys (55, 59, 63, 67 and 71%). Diets were corn-wheat-soybean meal-based with a constant SID Lys of 1.18% that was set to be second limiting amino acid. In Exp. 1 and Exp. 2, plasma-free Thr increased (P = 0.05) with increasing dietary SID Thr:Lys. In Exp. 1, the SID Thr:Lys for gain-to-feed ratio (G:F) was optimized at 65%. In Exp. 2, the estimated optimal SID Thr:Lys for overall G:F was 66.5%. In conclusion, an average optimal SID Thr:Lys of 65 and 66.5% could be used to optimize feed efficiency for weaned pigs under clean and unclean sanitary conditions, respectively.