EFFECTS OF SUPPLEMENTAL THREONINE ON THE PHYSIOLOGICAL RESPONSE, BONE MORPHOMETRY AND BONE MINERALS OF BROILER CHICKENS

Abstract

This study was carried out to evaluate the effect of supplemental threonine on the performance, physiological response, bone morphometry and bone minerals of Arbor Acres broiler chickens. One hundred and sixty (160) unsexed birds were randomly divided into four treatments. Each treatment had 4 replicates with each replicate having 10 birds. Thr1 (0 mg/kg), Thr2 (250 mg/kg), Thr3 (500 mg/kg) and Thr4 (750 mg/kg). Growth performance, physiological and bone health parameters were collected using standard protocols. Thr3 resulted in higher (P<0.05) final weight (2397.56g) compared to Thr1 (2322.08g), Thr2 (2327.04g) and Thr4 (2302.93g). Rectal temperature in Thr1 (42.76 0C) was significantly elevated (P<0.05) compared to Thr2 (42.58 0C), Thr3 (42.55 0C) and Thr4 (42.58 0C). Elevated respiratory rate (101.94 breaths/minute) and heart rate (216.92 beats/minute) were observed in Thr4. All bone minerals were significantly elevated (P<0.05) in Thr3. Density of the right femur in Thr2 (1.05) was higher (p<0.05) than that of Thr1 (0.09). Seedor index was also higher (p<0.05) in Thr1 (0.21) compared to Thr2 (0.18), Thr3 (0.17) and Thr4 (0.19). Thickness of left posterior epiphysis was significantly reduced (p<0.05) in Thr2 (11.10mm) compared to Thr3 (14.62mm) and Thr4 (15.04mm). The right anterior epiphysis was also influenced (p<0.05), Thr3 (13.00mm) and Thr4 (12.82mm) were thicker than Thr1 (8.46mm). The right posterior epiphysis had it width thicker (p<0.05) in Thr3 (16.07mm) compared to Thr1 (12.24mm). The study concluded that supplementing threonine at 500mg in diet of broilers improved the physiological status of the birds which in turn enhanced growth, thermo-response and bone health.