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 supplement on the growth performance and gut health of broilers subjected to nutritional challenges through a diet high in wheat and corn distiller's 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 + protease at 125 mg/kg (PRO); and 4) WD + EOA at 300 mg/kg + protease at 125 mg/kg (EOA + PRO). Body weight gain, feed intake and mortality rate did not differ among treatments (p &gt; 0.05). However, feed conversion ratio from day 1-35 was lower in the EOA+PRO group than in the WD group (p < 0.05). The EOA+PRO group had a lower crypt depth (CD) and a higher villus height/crypt depth (VH/CD) ratio than the other groups (p < 0.01). The putrescine level was higher in the WD group than in the other groups (p < 0.05). On day 35, the EOA and EOA+PRO groups had higher claudin-1 mRNA expression than the WD and PRO groups (p < 0.01). Occludin mRNA expression was higher in the EOA and PRO groups than in the WD group (p < 0.01). In summary, the combination of EOA and protease improved feed efficiency and gut health in broilers fed a high wheat and corn DDGS diet. This was demonstrated by decreased 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.