Abstract
BACKGROUND AND OBJECTIVES: This study aimed to assess the impact of diverse protein sources (soybean, mustard, rapeseed and black cumin [BC]) as dietary supplements on production performance, egg quality and gut microflora of Shaver Brown 579 commercial layers. METHODS: A randomized design allocated 324 hens over 4 months into six treatments with six replications for each treatment, each replication containing 09 birds. The treatments included T0 (control diet), T1 (basal diet + soybean), T2 (basal diet + mustard), T3 (basal diet + rapeseed), T4 (basal diet + mustard + BC) and T5 (Basal diet + Rapeseed + Black cumin). Production performances were assessed monthly and egg quality characters were assessed at 44th and 52nd weeks. RESULTS: Hens on diets featuring mustard, rapeseed and BC exhibited significantly higher body weight gain (BWG), without substantial impact on feed intake. The highest final body weight was observed in T5, with no mortality occurrences. No significant differences emerged in egg production, albumen index, shape index, shell breaking strength, shell thickness or shell percentage compared to control groups. However, egg weight showed significance in the third month (p < 0.05). Notably, dietary protein sources influenced gut microflora significantly (p < 0.05), with T0 having the highest microbial load and T5 the lowest. Egg production cost was the lowest in T4 (7.13 Tk. or $0.067/egg), where mustard oil cake and BC replaced soybean meal (SBM), whereas T1 recorded the highest cost (7.68 Tk. or $0.072/egg) using SBM. CONCLUSION: Mustard meal, rapeseed meal and BC are effective SBM substitutes in layer diets without any adverse effect on egg quality or production. These findings highlight the potential of mustard meal, rapeseed meal and BC as quality protein sources in commercial layer nutrition.