The effect of herbs and their associated essential oils on performance, dietary digestibility and gut microflora in young chickens from 7-28 days of age
Résumé
1. The effect of the dietary inclusion of 5 culinary herbs or their essential oils on the growth, digestibility and intestinal microflora status in female broiler chicks was assessed. From 7-28 days of age, either a basal control diet without supplement was fed or one of 10 others, consisting of the basal diet with either 10g/kg herb (thyme, oregano, marjoram, rosemary or yarrow) or 1 g/kg of essential oil. 2. Body mass and feed consumption were measured on a weekly basis and used to calculate chick performance. Total viable counts of lactic acid bacteria, coliforms, anaerobes and Clostridium perfringens were determined. Apparent nutrient digestibilities were calculated from the measured values for gross energy, N, DM, and organic matter, and the sialic acid concentration was also measured. 3. Thyme oil or yarrow herb inclusion in the diets had the most positive effects on chick performance, while oregano herb and yarrow oil were the poorest supplements. Interestingly, only thyme and yarrow in these diets had a different effect when introduced as an herb or oil. 4. Dietary treatment had no effect on the intestinal microflora populations, AME or the calculated coefficients of digestibility. The greatest concentration of sialic acid was measured in the birds fed dietary thyme oil. However, less sialic acid was excreted in those birds fed diets with marjoram, oregano or yarrow herbs, or with oregano or rosemary oils, than in the controls. 5. Plant extracts may be an alternative to conventional dietary supplements and may improve broiler chick performance. They may also influence gut health and endogenous secretions. This effect may depend on the type of extract used, which suggests the chemical composition of a plant supplement is important in obtaining optimal effects.
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