Effect of dietary orange and grapefruit peel on growth performance, health status, meat quality and intestinal microflora of broiler chickens

In our experiment we studied the effect of dietary orange peel (OP) and grapefruit peel (GP) on broilers health and thigh meat quality. The experiment was conducted on 126 Cobb 500 broiler chicks, assigned to three dietary treatments with 42 broilers per group. Each treatment was conducted in 3 experimental growth boxes, corresponding to 6 replicate pens per treatment and 7 broilers per pen. The growth boxes had identical size with a capacity of 3.5 m2 per box. Experimental dietary treatments differed from control diet (C) by addition of 2% OP or 2% GP supplement. A significant increase in body weight was exhibited in OP group compared to GP group (p < .05). Serum energetic profile (glucose, cholesterol and triglyceride) were lowered in both OP and GP supplemented groups compared to C birds (p < .05). Among fatty acids in thigh meat, OP group has increased the sum of PUFA compared to GP group. Dietary OP and GP have effectively reduced the oxidation process occurring during storage measured by the thiobarbituric acid–reactive substances (TBARS) values in thigh meat. Therefore, lipid oxidation was delayed by incorporating the two citrus peels in broiler diet. Monitoring the antimicrobial effect of OP and GP on intestinal and caecal microbiota population, the supplements reduced the growth of pathogenic Escherichia coli and Staphylococcus spp., proving their antimicrobial effect, while the beneficial bacteria, Lactobacillus spp. was significantly improved.Highlights The use of vegetable residues in the animal diets is an important economic and environmental factor. The positive effects were observed on thigh meat lipid oxidation, serum energetic profile and intestinal microflora of broiler chickens. Citrus peel in broilers feeding can act as natural antioxidant and feed additive