Essential oil blends in broiler chicken diets on performance, intestinal health and antioxidant enzyme activity

Abstract

The objective was to evaluate the inclusion of different commercial products based on essential oils in the diet of broiler chickens challenged by Eimeria vaccine and Clostridium perfringens as replacements for growth-promoting antibiotics. A total of 720 one-day-old male broiler chicks from the Cobb 500^® strain were distributed in a completely randomized design, with six treatments, six replications and 20 birds per experimental unit. The treatments consisted of: NC: negative control - basal diet without growth-promoting antibiotics; PC: positive control - basal diet with inclusion of growth-promoting antibiotic; NC+A: basal diet with inclusion of 100g ton^-1 product composed of cinnamaldehyde, carvacrol and thymol; NC+B: basal diet with inclusion of 1000g ton^-1 product composed of cashew oil (Anacardium occidentale) and castor oil (Ricinus communis); NC+C: basal diet with inclusion of 150g ton^-1 of product composed of eucalyptus extract (Eucalyptus), carvacrol, cinnamaldehyde, paprika oleoresin and vehicle and NC+D: basal diet with inclusion of 300g ton^-1 of product composed of organic acids, blend of essential oils, turmeric, tannins, vitamin E and zinc. At four days of age, all birds received orally 20 times the dose of Eimeria spp. vaccine, and seven and 10 days into the experiment, all birds were challenged with culture Clostridium perfringens. At one, 21 and 42 days of age, birds and feed were weighed to determine zootechnical performance. At 14 days of age, blood was collected from one bird per experimental unit to evaluate the enzymes superoxide dismutase, catalase, lactate dehydrogenase and aspartate aminotrasferase. At 14 and 28 days of the experiment, one bird per experimental unit was sacrificed for cecum collection for analysis of short-chain fatty acids and intestine (jejunum) samples for analysis of the intestinal health index and histomorphometry of the jejunum. At 18 days of experiment, one bird per experimental unit was orally administered a dose of fluorexin dextran isothicionate (FTC-d) for intestinal permeability analysis. The data were subjected to analysis of variance followed by the SNK test. For those that did not present have normal distribution, the Kriskal-Walis test and the Dunn test were used. All statistical procedures were conducted at 5% probability. There was a difference (P≤0.05) in weight gain and feed conversion at 21 days of age of the birds. The use of product D can improve the feed conversion of birds when compared to the positive control treatment. There was a difference (P≤0.05) for the intestinal health index at 14 days of age of the birds, the birds from product D had a lower total injury score when compared to the negative control treatment, product A and product C. There was a difference (P≤0.05) for the activity of the enzyme superoxide dismutase and aspartate aminotransferase, the inclusion of product B decreased the production of superoxide dismutase at 14 days of age when compared to C. There was a difference in the production of aspartate aminotransferase at 14 days of bird age, the inclusion of products C and D increases production compared to the negative control treatment. The use of product D based on organic acids, a blend of essential oils, turmeric, tannins, vitamin E and zinc can replace antibiotics as a growth promoter, promoting better feed conversion and a lower intestinal injury score.