Influence of dietary thymol and carvacrol preparation and/or an organic acid blend on growth performance, digestive organs and intestinal microbiota of broiler chickens

This experiment was designed to investigate the effects of supplementation with plant extract, either alone or in combination with an organic acid on growth performance, intestinal organ measurements and intestinal microbiology. One-day-old male Ross 308 strain broiler chicken (n=96) were allocated to 4 dietary treatments in a randomized complete block design. Dietary treatments were: (i) basal diet (as a control) (C), (ii) basal diet + organic acid mixture feed (OA), (iii) basal diet + plant extract (PE) and (iv) basal diet + organic acid mixture + plant extract feed (OA+PE). Body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were not improved by supplementation of OA or PE to the diets. Proventriculus, gizzard, hearth, liver, pancreas, abdominal fat and bursa of Fabricious weights were not significantly affected by dietary treatments. OA and PE diets resulted in increased weight and length of duodenum, jejenum, ileum and caceum. However, differences between treatments were not statistically significant (P>0.05). Supplementation of organic acid has positive effect on ileal microbiology. In ileal digesta, LAB and yeast counts were significantly (P<0.001) increased for birds fed OA and PE, whereas Escherichia coli counts were significantly (P