This experiment was conducted to assess the comparative effects of dietary antibiotics and oregano essential oil ( OEO ) addition on growth performance, antioxidant status and intestinal health of broilers. A total of 384 one-day-old broilers were randomly allocated to 4 treatments with 6 replicates of 16 broilers each. The 4 treatments were: an antibiotic-free control diet (control), control + 20 mg/kg colistin sulfate and 20 mg/kg virginiamycin (antibiotics), control + 200 mg/kg natural oregano essential oil ( NOEO ), and control + 200 mg/kg synthetic oregano essential oil ( SOEO ). The experiment lasted for 42 d. Results showed that birds fed with OEO had greater ( P < 0.05) average daily gain ( ADG ) and lower ( P < 0.05) feed conversion ratio ( FCR ) than those fed with control diet during d 1 to 21. Besides, birds fed with NOEO had the greatest ( P < 0.05) ADG in the four groups during d 22 to 42. The serum oxidative stress parameters showed that OEO improved ( P < 0.05) the activities of glutathione peroxidase ( GSH-Px ), superoxide dismutase ( SOD ) and glutathione reductase ( GR ) of birds on day 21 and the activity of total antioxidant capacity ( T-AOC ) of birds on d 42. Relative to control, NOEO increased ( P < 0.05) the activity of T-AOC in jejunum and decreased ( P < 0.05) the level of malondialdehyde ( MDA ) in serum and jejunum. Moreover, OEO supplementation increased ( P < 0.05) the concentrations of sIgA in duodenum and jejunum, Lactobacillus and total anaerobes in cecum, as well as activities of trypsin, chymotrypsin, lipase and amylase in duodenum, but restrained ( P < 0.05) the amount of Escherichia coli . The NOEO supplementation increased ( P < 0.05) total anaerobes of broilers on d 42 and the villus height to crypt depth ratio ( VH/CD ) of ileum. These results suggest that OEO improved antioxidant status and intestinal health of broilers which contributed to the growth performance improvement of broilers. Dietary OEO supplementation can be a promising alternative to antibiotic growth promoters for improving poultry production.

An experiment was conducted to determine effects of wheat bran (WB) phytase on production performance and nutrient utilization in laying hens. Three hundred and seventy-five Lohmann hens at 32 weeks of age were randomly allotted to treatments of fifteen hens per pen with five pens per treatment. Five experimental diets were formulated. Diet one (control) contained 0.19% inorganic phosphate (Pi) from dicalcium phosphate. On the basis of diet 1, diet 2 and 3 were formulated to contain WB 5% and 10%, respectively. In diet 4 and 5, the WB was fixed at the level of 10% with Pi level adjusted to 0.14% in diet 4 and completely replaced with 500 U/kg microbial phytase in diet 5. The results showed that treatment three improved egg yield (P = 0.142), feed conversion ratio (FCR) (P = 0.011), utilization of crude protein (CP) (P = 0.060) and total phosphorus (tP) (P < 0.001), and serum Pi concentration (P = 0.016) compared with the control. Ten percent of WB replacing 0.05% Pi did not influence either egg yield or nutrient utilization. Compared with the control, treatment five improved FCR (P = 0.011) and utilization of CP (P = 0.060) and tP (P < 0.001), but did not influence either performance or serum parameters. The current study suggests that wheat bran could be used successfully in laying hen diets and wheat bran and microbial phytase supplemented together could replace inorganic phosphate completely.

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