Growth performance of nursery pigs fed diets containing increasing levels of a novel high-protein corn distillers dried grains with solubles

Abstract

The objective of this study was to use the recently determined ME and standardized ileal digestibility (SID) values of AA for a novel high-protein distillers dried grains with solubles (HP-DDGS; PureStream 40, Lincolnway Energy LLC, Nevada, IA) to determine the optimal dietary inclusion rates in diets for nursery pigs. Three hundred and sixty pigs (BW = 6.79 ± 0.02 kg) were blocked by BW, and pens within blocks were assigned randomly to one of four dietary treatments (10 pens/treatment, 9 pigs/pen). Dietary treatments consisted of adding 0%, 10%, 20%, or 30% HP-DDGS to nursery diets during phase 2 (days 7-21) and phase 3 (days 21-42) of a three-phase nursery feeding program. Diets within each phase were formulated to contain equivalent amounts of ME, SID Lys, Met, Thr, and Trp, Ca, standardized total tract digestible P, vitamins, and trace minerals. Calculated SID Leu to Lys ratios for 0%, 10%, 20%, and 30% HP-DDGS diets were 119%, 137%, 156%, and 173% in phase 2 diets and 120%, 131%, 143%, and 160% in phase 3 diets. The SID Ile to Lys ratios ranged from 60% to 69% in phase 2 diets and from 54% to 59% in phase 3 diets. The SID Val to Lys ratios ranged from 63% to 79% in phase 2 diets and 64% to 68% in phase 3 diets. Body weight and feed disappearance were measured weekly. During phase 2, ADG, ADFI, and G:F were reduced linearly (P < 0.01) as the diet inclusion rate of HP-DDGS increased. Similarly in phase 3, increasing dietary levels of HP-DDGS depressed ADG, ADFI, and G:F linearly (P < 0.01). Overall growth performance of phases 2 and 3 of nursery pigs was negatively affected by increasing levels of HP-DDGS in these diets. Pigs acquired a Streptococcus suis and Escherichia coli disease challenge during the experiment. Although no differences in morbidity were observed throughout the experiment, including HP-DDGS in diets tended to decrease (P = 0.08) mortality. In conclusion, a linear decrease in nursery pig growth performance was observed as increasing levels of HP-DDGS were added in diets, which was probably due to overestimation of SID AA content of the HP-DDGS, antagonistic effects of excess Leu, and the effects of relatively high fiber content.

Keywords: branched-chain amino acids; growth performance; high-protein distillers dried grains; leucine; nursery pigs.