Physical treatment and protease or probiotic supplementation and feather meal digestibility by broilers

Context. Improving the utilisation of alternative protein ingredients in livestock production will reduce feeding costs and improve industry sustainability. Feather meal (FM) is an abundant, alternative protein source with a high protein content but poor amino acid (AA) digestibility. Aim. This study evaluated strategies for improving AA digestibility of FM. Methods. Experiment 1 examined the effects of physical treatment with ultrasound, microwave and autoclaving on FM AA profile and digestibility. Experiment 2 evaluated the dietary addition of a protease (Ronozyme ProAct, 200 and 600 mg/kg; RPA) and a probiotic (BioPlus 400, 1500 mg/kg) on FM AA digestibility. Apparent ileal digestibility was determined by feeding each treatment to four replicate groups of six birds in Experiment 1 and five replicate groups of seven birds in Experiment 2, and then collecting the contents of the lower half of the ileum. Key results. None of the physical treatments improved (P > 0.05) the AA profile or ileal AA digestibility of FM. Dietary supplementation with RPA at 200 mg/kg or BioPlus 400 at 1500 mg/kg did not significantly (P > 0.05) influence the apparent ileal AA digestibility of FM. However, the higher concentration of RPA (600 mg/kg) significantly (P < 0.05) increased the apparent ileal AA digestibility of FM. Conclusion. The increased digestibility of FM by the protease and numerical increase (P < 0.1) by the probiotic (1500 mg/kg) presumably reflects keratinase activity of both feed supplements. Implications. The results of this study indicated that there is scope for further improvement in the nutritive value of FM for broilers.