Evaluation of potentials of bioactive compounds extracted from purple onion (Allium cepa L.) for culturing Lactobacillus plantarum to develop probiotics in broilers

This study evaluated potentials of purple onion (Allium cepa L.) extract and its application in probiotics as a feed additive for broilers. The results showed that purple onion extract contained compounds with prebiotic potential with high contents of Fructooligosaccharide, Quercetin 3,40-diglucoside, Quercetin 40-monoglucoside and Quercetin aglycone, which promoted the growth of all three strains L. plantarum 1582, L. plantarum WCFS1, L. plantarum JDM1, especially at 40% dilution. The strain L. plantarum 1582, which exhibited superior probiotic properties (acid resistance 8.97 log CFU/g, bile salt tolerance 10.42 log CFU/g, temperature tolerance 7.51 - 8.10 log CFU/g, maintaining a high cell density in gut after 24 - 72 h 4.93 - 5.96 log CFU/g), was used in the in vivo purple onion fermented product test. Oral administration of the fermented product to broiler chickens showed that L. plantarum 1582 survived well in the gastrointestinal tract, especially in the small intestine and ceca for 24 - 48 h. It can be concluded that the purple onion extract has potential as a prebiotic and the purple onion-fermented product with L. plantarum 1582 can be used as a feed additive. However, further in vivo studies are needed to evaluate the efficacy of this product under real conditions.