Synergistic Effect of Citric By-Product, Fibrolytic Enzyme and Lactobacillus spp. to Enhance Broiler Performance

This study evaluated the effects of citric acid by-product (CABP), either alone or in combination with fibrolytic enzyme (F) and <i>Lactobacillus</i> spp. (L), in broiler diets. A total of 160 one-day-old male Arbor Acres broiler chicks (average initial body weight 43.0 ± 0.16 g) were randomly assigned to four CABP-based diets (4 replicates × 10 birds each): 12% CABP, CABP+F (0.05%), CABP+L (0.025%), and CABP+FL (0.05% F + 0.025% L). Birds were fed for 35 days in three phases: starter (days 1-10), grower (days 11-24), and finisher (days 25-35). Compared with the CABP-only group, broilers receiving CABP+F, CABP+L, or CABP+FL exhibited higher body weight and weight gain during the finisher and overall phases (<i>p</i> < 0.05). Carcass traits did not differ significantly among treatments, although meat hardness was reduced in the CABP+FL group (<i>p</i> < 0.05). Additive-supplemented groups also showed changes in intestinal morphology, with a lower villus height-to-crypt depth ratio compared with CABP alone. Red blood cell counts were not different between CABP and CABP+L, while hepatic enzyme activities (ALT, AST, ALP) remained unchanged across treatments, indicating no adverse effects on liver function. Overall, supplementation of CABP-based diets with fibrolytic enzymes and/or <i>Lactobacillus</i> spp. improved broiler performance and certain meat quality traits relative to CABP alone, without negative impacts on liver health or carcass yield. However, as no conventional corn-soy control diet was included, the results should be interpreted as comparisons within CABP-based diets.