Inclusions of diverse sorghum hybrids in diets based on wheat-sorghum blends support entirely satisfactory broiler...

This study compared five diverse sorghum hybrids (Liberty, Cracka, Buster, Resolute, A66) in broiler chicken diets on growth performance, carcass traits, energy utilisation and nutrient digestibility from 14 to 30 days post-hatch. The five sorghums were included in diets based on wheat-sorghum blends with fixed inclusions of 380 g/kg sorghum, 250g/kg wheat and 165 g/kg soybean meal. A total of 360 mixed-sex, Ross 308 broiler chickens were randomly allocated to five dietary treatments, with six replicate cages per treatment and 12 birds per cage. Significant differences were not observed in growth performance across the five dietary treatments, which also applied to carcass traits at day 30. Significant differences between treatments were observed for apparent metabolisable energy (AME; P = 0.009) and nitrogen-corrected AME (AMEn; P = 0.002) where Resolute was inferior to the other four hybrids. There were significant differences for distal jejunal starch digestibility coefficients (P = 0.001), which ranged from 0.857 to 0.907 around a mean of 0.892. Significant differences were observed in the jejunum (P = 0.001) and ileum (P = 0.025) for protein (N) digestibilities, which averaged 0.400 and 0.654, respectively. Instructively, rapid visco-analysed (RVA) starch pasting profiles were correlated with several performance parameters. Indeed, all five RVA starch pasting parameters (peak, trough, breakdown, final, setback) were positively correlated with FCR, indicating their potential as indicators of sorghum starch quality in poultry feed. Finally, the average growth performance supported by the five sorghum hybrids in diets based on wheat-sorghum blends comfortably exceeded current Aviagen objectives for weight gain by 21.3 % (1543 versus 1272 g/bird) and feed intake by 20.7 % (2200 versus 1822 g/bird) and fractionally improved FCR by 0.42 % (1.426 versus 1.432). Thus, the observed broiler growth performance was entirely satisfactory and given its drought tolerance, sorghum remains a sustainable and viable grain option for Australian chicken-meat industry depending on its landed cost at feed-mills relative to wheat.