δ-Aminolevulinic acid, and lactulose supplements in weaned piglets diet: Effects on performance, fecal microbiota, and in-vitro noxious gas emissions

δ -Aminolevulinic acid (ALA) is a non-protein amino acid that plays a rate limiting role in the process of heme biosynthesis. Lactulose (LAC) is a kind of non-digestible oligosaccharides which has been shown to improve growth performance in weaning pigs through prebiotic actions. This study evaluated the efficacy of ALA, and LAC in weaned piglets. The study was conducted with one hundred seventy five [(Yorkshire×Landrace)×Duroc] weaned piglets in a 33 d feeding trial, and one of five diets: 1) CON (basal diet, no antibiotic); 2) ALA05 (CON+0.5g ALA/kg of diet); 3) ALA10 (CON+1g ALA/kg of diet); 4) LAC05 (CON+0.5g LAC/kg of diet); 5) LAC10 (CON+1g LAC/kg of diet). All data were statistically analyzed using the PROC MIXED procedure of SAS. Orthogonal contrasts were used to the effects of treatments. Weaning pigs fed diets with the ALA, and LAC had higher body weight (BW) compared with pigs fed the CON diet on d 19 (P=0.028, and 0.011), and d 33 (P=0.031, and 0.015), respectively. In addition, LAC supplementation had higher BW than ALA supplementation (P=0.046) on d 19. Piglets fed diets with ALA, and LAC had higher average daily growth (ADG), and feed efficiency (G:F) compared with piglets fed CON diet during phase 2 (d 6–19), and overall (d 1–33), respectively (P<0.05). Besides, LAC diets improved ADG (P=0.037), and G:F (P=0.024) compared with ALA diets during phase 2. Weaned piglets fed LAC increased dry matter (DM; d 19, and 33, respectively), nitrogen (d 33), and energy (d 19) digestibility compared with those fed CON diet (P<0.05). ALA supplementation increased DM digestibility compared with CON diet (P=0.041) on d 33. Piglets fed with the ALA diet increased serum total iron-binding capacity, hemoglobin, and hematocrit, and blood red blood cell compared with those fed the CON diet (P<0.05). Piglets fed with the LAC diet increased fecal Lactobacillus, and reduced E. coli counts (P<0.05) when compared with those fed the CON on d 19, and 33, respectively. Moreover, piglets fed with the LAC diets had higher fecal Lactobacillus (d 19, and 33), and lowered E. coli (d 33) than pigs those fed the ALA diets (P<0.05). The fecal moisture, and diarrhea score were not affected by dietary supplementation with ALA or LAC during the whole experiment. Piglets fed the LAC diets had reduced ammonia gas emissions compared with the CON diet on d 33 (P<0.001). In conclusion, results indicated that dietary supplementation of ALA, and/or LAC improved performance, and reduced noxious gas emissions in weaned piglets.