Targeted-Release Organic Acids and Essential Oils Improve Performance and Digestive Function in Broilers under a Necrotic Enteritis Challenge

SIMPLE SUMMARY: Controlling digestive diseases in the poultry industry is crucial to maximize profitability. Necrotic enteritis (NE) is a real threat for poultry that leads to high financial losses. Microencapsulated blends of organic acids and essential oils have gained increasing interest as feed additives that could alleviate the effects of these diseases by controlling the intestinal microbiota and enhancing the gut function of broiler chickens. Organic acids actually used as feed additives, including short-chain fatty acids (C1-C6), medium-chain fatty acids (C7-C12), and other organic acids, may show a range of variable physiological effects in the animals when combined with different phytogenic compounds. This study was designed to understand the mechanisms of action of these feed additives, their effect on intestinal morphology and growth performance, as well as their interaction with the gut microbiome. Our results provide evidence on the importance of designing proper combinations and doses of these additives to enhance growth performance, the microbiota profile, and histomorphology. Dietary supplementation of 0.5 g/kg of BUTYTEC-PLUS and 2 g/kg of ACITEC-MC as microencapsulated blends are recommended to improve broiler chickens performance under NE challenge due to their positive effect on gut microbiome and the absorptive capacity of the intestine. ABSTRACT: An experiment was performed to evaluate the effect of four different microencapsulated blends of organic acids (OA) and nature-identical aromatic compounds (AC) on growth performance and gut health of broilers challenged with a recycled NE litter. A total of 600 one-day-old male Ross 308 broilers were randomly assigned to five treatments consisting of a basal diet (as negative control) supplemented with each of the tested microencapsulated blends: OA1 (malic and fumaric acid) + AC; 2.5 g/kg; OA2 (calcium butyrate+fumaric acid) + AC; 1.7 g/kg; MCFA (capric-caprylic; caproic and lauric acid) + AC; 2 g/kg; and MCFA + OA3 (calcium butyrate+fumaric and citric acid) + AC; 1.5 g/kg. The AC used was the same for all treatments; including cinnamaldehyde, carvacrol, and thymol (8:1:1), as major compounds. Three tested blends enhanced growth performance by improving intestinal histomorphology (p < 0.001). The tested blends enhanced the abundance of some beneficial families such as Ruminococcaceae and Lachnospiraceae; while reducing that of harmful ones such as Enterobacteriaceae and Helicobacteraceae. A further dose-response experiment showed that 0.5 g/kg of the blend 2 and 2 g/kg of the blend 4 improved growth performance and intestinal histomorphology of chickens on d 42 and decreased fecal Enterobacteriaceae and C. perfringens counts. Similar effects to the previous experiment were observed for cecum microbiota.