Fig. 3
Intestinal damage of housefly larvae fed by different groups. A Positive trypan blue staining was present in the Cu, CuK, P, and CuP groups. No signs of tissue damage were observed in the Lb and K larvae. B Damaged tissue sections of domestic fly larvae in different experimental groups (100 ×). Abbreviations: Lb, Luria–Bertani medium; Cu, CuSo4; K, K. pneumoniae solution; CuK, Mixed solution of K. pneumoniae and CuSO4; P, K. pneumoniae phage; CuP, Mixed solution of K. pneumoniae phage and CuSO4. Asterisks indicate significant differences at *p < 0.05, **p < 0.01, ***p < 0.001,****p < 0.0001