PSV-15 - Effect of functional amino acids and fiber on growth performance of post-weaning pigs

Abstract: This study evaluated the effect of increasing levels of functional amino acids (FAA), including Met, Thr, and Trp with 1.4% standardized ileal digestible (SID) Lys on performance and the effect of high levels of fiber when high levels of FAA combined. A total of 216 pigs [21 days old; 6.46 ± 0.63 kg body weight (BW)] were allotted to one of 6 treatments with 3 pigs of single sex per pen, and 12 replicates/treatment. Treatments were: 1) Control basal diet (BD), 2) BD + 23% more Met+Cys (HMet), 3) BD + 22% more Thr (HThr), 4) BD + 20% more Trp (HTrp), 5) BD + 20% more Met, Thr, and Trp (HFAA, with 9% NDF and 4%ADF), 6) HFAA+ high fiber (27% NDF and 18% ADF in diet by adding soy hulls at expense of corn, HFAA+HF). The experiment lasted for 42 days and pigs were fed experimental diets for 21 days followed by a common diet for the last 21 days. Pigs fed HFAA+HF diet were initially fed HFAA diet for the first 8 days and followed by HFAA+HF diet for the next 13 days, and fed the common diet during the last 21 days. On days 0, 9, 21, and 42, BW and feed intake were recorded, and fecal scores (1 as normal to 4 as watery diarrhea) were assessed during the trial. Data were analyzed using the lme4 package of R 4.1.2, and the statistical models included the fixed effect of treatment and random effect of sex and BW block. Growth performance data were analyzed as single factor ANOVA, whereas stool quality was analyzed using ordinal model. Contrasts were used to test the effects of FAA (by comparing treatments 2, 3, 4, and 5 to BD and fiber (by comparing HFAA+HF to HFAA). Pigs fed HFAA had reduced (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI) from day 21 to 42 and tended (P < 0.10) to have reduced overall ADG compared to BD. Increasing individual amino acids did not affect performance, with the exception that pigs fed HTrp tended (P < 0.10) to have increased gain:feed (G:F) from day 21 to 42 compared to BD. High fiber levels did not affect ADG or ADFI, however, it reduced (P < 0.05) G:F during the whole trial compared to HFAA. Treatment did not influence stool quality. In conclusion, combination of high levels of Met, Thr, and Trp with SID 1.4% Lys under non-disease challenged conditions resulted in a reduction of performance, but this was not the case with increased individual amino acids, and high fiber level with high level of FAA reduced feed efficiency of pigs.