Effects of ethanol extract of elecampane (Inula helenium L.) rhizome on growth performance, diet digestibility, gut health, and antioxidant status in broiler chickens

Abstract

This study tested the efficacy of ethanol extract of elecampane (Inula helenium L.) rhizome (EEER) upon growth performance and physiological characteristics of broiler chickens. A total of 360 one-day-old male broiler chickens were randomly allocated to 4 treatments with 6 replicates and 15 chickens per replicate. Treatments consisted of different EEER concentrations (0, 250, 500, or 1000 mg/kg) included in a diet of 3-phase feeding program (starter, grower, and finisher) during the periods of 1–10, 11–24 and 25–42 days of age, respectively. Feed intake was not affected by dietary treatments throughout the study. However, considering the grower and finisher periods or the whole experiment, there were linear improvements in body weight gain and feed conversion ratio with increasing inclusion rate of EEER (P < 0.05). Increasing dosages of EEER produced linear increases in digestibility of dry matter, organic matter, ether extract, and gross energy (P < 0.05). Apparent digestibility of crude protein was not different among diets. A decrease in the count of Escherichia coli (P < 0.05; quadratic) and Clostridium spp. (P < 0.05; linear) along with an increase in the count of Lactobacillus spp. (P < 0.05; linear and quadratic) was also observed with dietary EEER. Diet supplementation with EEER showed positive effects on intestinal mucosa development and intestinal antioxidant capacity. In ileum, there were linear increases in villus height and villus/crypt ratio and linear decreases in crypt depth and total mucosa thickness with increasing addition of EEER (P < 0.05). A linear increase in villus height and a parallel increase in villus/crypt ratio was also evident in the jejunum (P < 0.05). However, crypt depth and total mucosa thickness of the jejunum were not influenced by dietary treatments. In both the jejunal and ileal mucosa, dietary EEER induced a dose-related increase in the activities of superoxide dismutase, catalase, and glutathione peroxidase (P < 0.05), which was accompanied by a linear decrease in the content of malondialdehyde (P < 0.05). In conclusion, EEER can be considered as a suitable feed additive, which can have positive effects on growth performance, intestinal flora, and gastrointestinal health in broiler chickens.