Effect of microencapsulated organic acids-essential oils blend and protease on performance and gut health of broilers under nutritional challenges

This study examined the effects of microencapsulated organic acids and essential oils (EOA) combined with a protease (PRO) supplement on the growth performance and gut health of broilers subjected to nutritional challenges through a diet high in wheat and corn distillers dried grains with solubles (DDGS). The treatments were: 1) corn and soybean meal-based diet with high levels of wheat and corn DDGS (WD); 2) WD+microencapsulated organic acids and essential oils at 300 mg/kg (EOA); 3) WD+PRO at 125 mg/kg (PRO); and 4) WD+EOA at 300 mg/kg+PRO at 125 mg/kg (EOA+PRO). Body weight gain, feed intake and mortality rate did not differ among treatments (<i>p</i> > 0.05). However, feed conversion ratio from day 1-35 was lower in the EOA+PRO group than in the WD group (<i>p</i> < 0.05). The EOA+PRO group had a lower jejunal crypt depth (CD) and a higher villus height/crypt depth (VH/CD) ratio than the other groups (<i>p</i> < 0.01). The putrescine level was higher in the WD group than in the other groups (<i>p</i> < 0.05). On day 35, the EOA and EOA+PRO groups had higher claudin-1 mRNA expression than the WD and PRO groups (<i>p</i> < 0.01). Occludin mRNA expression was higher in the EOA and PRO groups than in the WD group (<i>p</i> < 0.01). In summary, the combination of EOA and PRO improved feed efficiency and gut health in broilers fed a high wheat and corn DDGS diet. This was demonstrated by decreased jejunal CD, increased VH/CD ratio, increased mRNA expression of claudin-1 at the tight junction and decreased putrescine content in the hindgut, suggesting an indirect effect on pathogenic bacteria.