Replacement of Antibiotic Growth Promoter by Probiotic in the Diet Increases Intestinal Peptide Transporter RNA Expression in Broilers

Probiotics and essential oils have been investigated as replacements for antibiotic growth promoters (AGP) by improving the performance and gut health of chickens. However, studies reported contrasting responses from these additives in intestinal digestion and absorption. We investigated the effects of addition of Bacillus subtilis (Probiotic), a essential oil blend (carvacrol , cinnamaldehyde, cineol and pepper extract) or their combination in the expression of genes related to digestion and absorption in coob® broilers, by RT-qPCR. Birds were created throughout the period in accordance with the strain recommendations. Basal diet was used as negative control and the avilamycin AGP as positive. At 21 and 42 days of age, 6 birds per treatment were slaughtered to collect the mucosa of the ileum to analysis. The investigated genes were: aminopeptidase N (APN) , sucrase isomaltase (SI), maltase-glucoamylase (MGA), intestinal transporter peptide-1 (PEPT1), transporter of glucose and galactose Na⁺ dependent-1 (SGLT-1), glucose transporter, galactose and fructose independent Na⁺-2 (GLUT -2) and ATP ase Na⁺/ K⁺ (ATP1A-1). Birds fed probiotics showed relative amounts of mRNA of PEPT-1 greater than those fed with AGP and that birds fed essential oil, respectively, at 21 and 42 days. Also at 42 days, the expression of the ATP1A-1 gene in birds fed probiotic exceeded the observed in birds fed AGP, as those who received the basal diet. The improvement in ATP1A-1 and PEPT-1 RNA expression observed herein should be evaluated for translation into protein and in the uptake of peptides in the gut in probiotic fed broilers.