Impact of Incorporating Defatted Black Soldier Fly Meal into Diet on Growth Performance, Serum Biochemical Parameters, Nutrient Digestibility, Morphology of the Intestinal Tract, and Immune Index of Brooding Laying Hens

The aim of this study was to investigate the impact of incorporating black soldier fly meal (BSFM) into the diet of brooding laying hens, with a focus on growth performance, serum biochemical markers, nutrient digestibility, intestinal morphology, and immune responses. A total of 480 one-day-old chicks (Hy-Line Brown, commercial flock) were randomly divided into four dietary treatment groups, each consisting of six replicates with 20 birds per pen. One group was fed a basal control diet (control/G0 group), while the remaining three groups were fed 3% (G3 group), 6% (G6 group), and 9% (G9 group) BSFM, respectively. The study lasted for 42 days. At both 21 and 42 days of age, several parameters were measured, including average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), and tibia length. Blood serum samples were also collected to assess biochemical and antioxidant indicators. Results showed that the ADG in the G3 group was significantly higher than the G0 group during the 1-21, 22-24, and 1-42 day periods (<i>p</i> < 0.05). The F/G ratio in the G3 group was significantly lower than that of the G0 group during the 1-21 day period (<i>p</i> < 0.05). However, there were no significant differences in ADFI or tibia length across the groups (<i>p</i> > 0.05). The total protein and globulin levels in the G3 and G6 groups were significantly higher than those in the G0 group (<i>p</i> < 0.05). Additionally, blood urea nitrogen levels in the G3 group were significantly higher than in the G0 group (<i>p</i> < 0.05). Conversely, triglyceride levels were significantly lower in the G3 and G6 groups compared to the G0 group (<i>p</i> < 0.05). Total antioxidant activity was significantly higher in the G6 and G9 groups than in the G0 group (<i>p</i> < 0.05). The treated groups also exhibited higher glutathione peroxidase (GSH-Px) activity and lower malondialdehyde (MDA) levels compared to the G0 group (<i>p</i> < 0.05). However, there were no significant differences in total superoxide dismutase activity across the groups (<i>p</i> > 0.05). In conclusion, this study indicates that BSFM can serve as a high-quality protein raw material in the process of laying hen breeding, highlighting its potential as a viable insect protein source in the poultry feed industry.