Effect of protein level in maternal and weanling diets on performance and fecal consistency of weaned pigs

Low protein levels in weaning diets have been associated with lower risk for diarrhea, which could improve piglets’ gut health, and decrease antibiotic use in animal production. The mismatch theory presumes that animals can be prepared during fetal development for certain postnatal situations. Therefore, we investigated the effect of two levels of crude protein in late-gestation diet and piglet post weaning diet on the offspring’s susceptibility for diarrhea post weaning and performance until slaughter.
The hypothesis was tested in a 2x2 factorial trial, with high and low protein levels in sow diets (12 vs 17% crude protein (CP)) during the last five weeks of gestation and high or low, one-phase nursery diet (16.5 vs 21% CP). Resulting in four treatments of the four combination of high (H) and low (L) protein diets. All diets were supplemented with amino acids (AA), to reach or exceed the ideal AA-composition. The faecal consistency was measured during the nursery phase of the piglets. Performance of the piglets was registered from birth until slaughter. Statistical analysis was performed using RStudio with linear mixed-effect models (lme4 package), pairwise comparison and estimated measures of means (emmeans package).
For performance, no difference was found between treatments. Daily gain (g) did not differ from weaning until 9 weeks (LL 372.00±20.3, LH364.00±7.23, HL370.00±18.8, HH 377.00±4.92), or from 9 weeks until slaughter (LL 766.85±16.62, LH 807.07±32.31, HL 792.11±24.4, HH 804.87±21.15). Feed conversion ratio did not differ from weaning until 9 weeks (LL 1.39±0.04, LH 1.42±0.02, HL 1.42±0.03, HH 1.35±0.02) or from 9 weeks until slaughter (LL 2.45±0.02, LH 2.53±0.05, HL 2.48±0.03, HH 2.39±0.07). For faecal consistency, no interaction between maternal and piglet diet was found. Lower protein in the gestation diet lead to higher diarrhea scores post weaning, while lower protein in the piglet diets tended to lead to lower diarrhea scores. In summary, the difference in dietary protein levels for sows and piglets did influence weaning diarrhea, but did not influence the performance of piglets.