Effect of Diet Compositions on Colony Strength Parameters, and the Enzymatic Activity of Apis mellifera L. During Floral Scarcity

Dearth periods associated with less floral resources negatively impact Apis mellifera colony performance. Artificial diets offer nutritional supplements to sustain bee colonies under stressful conditions. An eight-week feeding trial was conducted using various artificial diets (eight diets, including a control diet), formulated with varying quantities of pulses, yeast, fenugreek powder, vegetable oil, dry apricot powder, and powdered sugar. Colony performance of bees subjected to different artificial diets was evaluated based on diet consumption, brood area, adult bee population, worker bee longevity, honey production, and enzymatic activity. Diet-7, which uniquely combined lupin, mung bean, and chickpea flours, proved the most efficacious and was the most consumed diet (84.29 ± 1.61 g), while diet-1 showed the lowest consumption (35.30 ± 1.08 g). Maximum brood area was recorded in colonies which were offered diet-7 (1385.95 ± 14.91 cm2), followed by diet-6, whereas the lowest was observed in the control (831.03 ± 18.95 cm2). The adult bee population was highest in diet-7 (21,594.50 ± 94.55 bees/hive), while lowest in the control (diet-0) (12,625.43 ± 385.06 bees/hive). Worker bee longevity was greatest in diet-7 (49.40 ± 0.41 days) and lowest in the control group (37.01 ± 0.39 days). Honey production was also highest in diet-7 (8.86 ± 0.21 kg), while lowest in the control (2.79 ± 0.35 kg). The results further showed that the enzymatic activities of bees were significantly improved due to diet-7, with the highest values for amylase (48.62 ± 0.23 U/mg), lipase (16.85 ± 0.20 U/mg), proteinase (25.21 ± 0.18 U/mg), and α-glucosidase (39.21 ± 0.21 U/mg). In conclusion, statistical analyses confirmed that diet-7 emerged as the most effective artificial diet, enhancing colony performance across all evaluated parameters. Future research should aim to optimize diet formulations and evaluate their effectiveness on colony health, including gut microbiome and immune function, across different seasons and ecological regions.