Interaction between Protein Sources (wheat gluten and protein concentrate from soy and potato) and Starch Sources (pre-gelatinized and native pea starch) on Weanling Pig Growth Performance and Diarrhea Incidence

The interaction between 2 protein sources [wheat gluten (9.1%) and protein concentrate from soy and potato (7.36% and 5.09%, respectively)] and 2 starch sources [digestible starch (20% pre-gelatinized pea starch) and resistant starch (20% native pea starch)] on growth performance and diarrhea incidence of weanling pigs were investigated. A total of 240 weaned piglets (24 d of age, 7.24 ± 0.40 kg BW) were randomly allocated to 40 pens in a 2 × 2 factorial arrangement of treatments (6 pigs/pen; 10 pens/treatment). The 4 diets were: (1) wheat gluten + pre-gelatinized pea starch, (2) wheat gluten + native pea starch, (3) soy and potato protein concentrate + pre-gelatinized pea starch, (4) soy and potato protein concentrate + native pea starch. Diets were formulated to be isocaloric (2,400 kcal NE/kg), isonitrogenous (19% CP), equal in SID Lys (1.28%), Met+Cys (0.77%), Trp (0.26%), Thr (0.80%), Ile (0.74%), Val (0.84%), and met CVB (2016) recommendations. Pig ADG, ADFI, and G:F were determined weekly and fecal score was determined daily. Data were analyzed using PROC MIXED of SAS with starch, protein, and interaction of starch and protein sources as fixed effects and block as the random effect. During wk 1 post-wean, no differences in growth performance and diarrhea incidence were observed among pigs fed dietary treatments. Overall (wk 0 to 6), pigs fed soy and potato protein concentrate resulted in 18% higher ADG, 18% greater ADFI, and 3 kg greater final BW than those fed wheat gluten (P < 0.05). From wk 2 to 4, diarrhea incidence was 38.4% in pigs fed soy and potato protein concentrate which was greater (P < 0.05) compared with pigs fed wheat gluten (26.9%), while the opposite trend was observed from wk 5 to the end of the study, in which pigs fed soy and potato protein concentrate had 5.5% diarrhea incidence which was less (P < 0.05) compared with wheat gluten (14.7%). Increasing resistant starch in the soy and potato protein concentrate diet reduced diarrhea incidence, while its inclusion in the diet containing wheat gluten led to a tendency for higher diarrhea incidence from wk 5 after weaning (P < 0.10). Study results suggest that soy and potato protein concentrate improves growth performance in weanling pigs, and combining with resistant starch in the diet from wk 5 post-wean can decrease diarrhea incidence. Wheat gluten can be beneficial in reducing diarrhea incidence in the first 4 wks post-wean.