Lactiplantibacillus plantarum ameliorated the negative effects of a low-protein diet on growth performance, antioxidant capacity, immune status, and gut microbiota of laying chicks

This experiment was conducted to investigate the effects of adding <i>Lactiplantibacillus plantarum</i> to a low-protein diet on the growth performance, ability immune status, and intestinal microbiota of 0-21-day-old layer chickens. A total of 180 one-day-old healthy Hy-line brown laying chicks were randomly divided into three groups with three replicates each of 20 chicks. The control group was fed a basal diet containing 19% protein, the low-protein (LP) group was fed a diet containing 17% protein, and the probiotic (LPL) group was fed with the 17% protein diet supplemented with <i>L. plantarum</i> (1.0 × 10⁹ CFU/kg). The growth performance, antioxidant capacity, immune status, and gut microbiota of laying chickens were detected. We found that <i>L. plantarum</i> supplementation increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and levels of immunoglobulin (Ig) A, IgG, and interleukin-10 (IL-10) in serum of 17% protein +1.0 × 10⁹ CFU/kg <i>L. plantarum</i> (LPL) compared to the 19% protein group (control). Furthermore, <i>L. plantarum</i> supplementation increased the liver index, GSH-Px and T-AOC activity in serum, and changed the microflora structure, diversity, and polyketose unit bioanabolic metabolism of 17% protein +1.0 × 10⁹ CFU/kg L. plantarum (LPL) compared to the 17% protein group (LP). In conclusion, <i>L. plantarum</i> supplementation could compensate for the adverse effects of low-protein diets in chicks, and the combination of a low-protein diet and <i>L. plantarum</i> is a feasible way to reduce protein in the diet.