Eureka! Institutional Repository

Moschopoulos, V., 2020. Effect of dietary mint essential oil supplementation on performance and egg quality of laying hens. Master of Science thesis, Specialization “Precision Livestock Systems” of the Postgraduate Studies Programme “Master in Innovative Systems of Sustainable Agricultural Production”, Department of Agriculture, School of Geotechnical Sciences, International Hellenic University. Thessaloniki, Greece, pp. 1–130. In an experiment with 36 laying hens (ISA Brown), 79 weeks of age, effects of dietary mint essential oil (MEO, Mentha piperita L.) supplementation on layers’ performance and egg quality was determined. In the 8 week experiment, hens were allocated to three dietary treatments (MEO0, MEO500 and MEO1000) of 12 hens each, accommodated to 6 cages (replicates)/treatment of 2 hens each and received a specified amount of diet (concentrate mixture in mass form, 130 g/hen/day). The MEO was added to the diet at inclusion levels of 0, 500 and 1,000 mg/kg for treatments MEO0 (control), MEO500 and MEO1000, respectively. During the experiment, no differences (P>0.05) occurred among MEO treatments in final body weight (1,907 g), body weight change (20.1 g), feed intake (111.8 g), egg production (0.831 eggs/hen/day), production of cracked, thin-shelled and shell-less eggs (0.014 eggs/hen/day), egg weight (62.70 g), egg mass (52.05 g) and feed efficiency (2.188 g feed/g egg mass). In addition, yolk colour (6.88 vs. 7.54) increased (L: P<0.05) and albumen weight (41.57 g vs. 38.34 g) decreased (L: P<0.05), with increasing dietary MEO inclusion levels, and egg length and egg shape index increased (Q: P<0.05, maximum in treatment MEO500 and MEO1000, respectively). No other egg quality characteristics were affected (P>0.05). No differences (P>0.05) occurred among MEO treatments in yolk dry matter-DM (45.34 g DM/100 g) and albumen DM (9.76 g DM/100 g). Yolk lipid content (62.49 vs. 60.58 and 59.67 g/100 g yolk DM) and yolk water-soluble protein content (110.45 vs. 77.56 and 65.71 mg/g yolk DM) decreased (L: P<0.05), and antioxidant activity – DPPH (24.66 vs. 35.69 and 45.28 μg TE/g yolk DM) and antioxidant activity – ABTS (278.81 vs. 417.93 μg TE/g yolk DM) increased (L: P<0.05), with increasing dietary MEO inclusion levels. Dietary MEO supplementation, at inclusion levels up to 1,000 mg/kg of concentrate mixture, did not affect performance of laying hens and most egg quality characteristics, while decreased yolk lipid and water-soluble protein contents and increased yolk antioxidant activity.