To investigate the supplemental effects of Hermetia illucens larvae meal (HILM) on the production, egg quality, yolk fatty acid composition, egg amino acid content, oxidative status, and immune indexes of laying hens. A total of 432 Xuefeng black-bone chickens (45-week-old) were randomly assigned to 4 treatments with 6 replicates per treatment and 18 hens in each replicate. The laying hens were fed the basal diet supplemented with 0%, 1%, 3%, and 5% HILM (CON, HILM-1, HILM-3, and HILM-5, respectively) for 56 d. The experimental diets were isonitrogenous and isoenergetic. The highest egg weight and Haugh unit were obtained with 3% HILM supplementation, but the HILM-3 or HILM-5 supplementation have negative effect on the eggshell thickness, yolk index, and albumen height during the early stage of the experiment. The HILM supplementation linearly or quadratically (p < .05) increased the C14:0, C17:0, C18:2n6c, C20:2 contents of yolk, the Glu, Val, Met, Phe, and Leu contents of egg, the T-SOD and CAT activities, and the NDV-Ab and AIV-Ab levels of plasma. With increasing supplementation of HILM in the basal diet, FCR, the C16:0 and C16:1 contents of yolk, MDA content and IL-2 level of plasma decreased both linearly or quadratically (p < .05). In conclusion, Hermetia illucens larvae meal can be a suitable alternative protein source for Xuefeng black-bone chicken. Dietary supplementation of 3% HILM in basal diets may be a feasible means of effectively increasing the production performance of laying hens, and partially enhanced hens' antioxidant capability and immune function. HIGHLIGHTS Supplementation of 1% HILM had no effect on laying hens, and supplementation of 3% HILM increased the egg weight and Haugh unit. Supplementation of 3% HILM or 5% HILM have a negative effect on the eggshell thickness, yolk index, and albumen height during the early stage of the experiment. Supplementation of 3% HILM increased the C14:0, C17:0, and C20:2 contents of yolk, the Glu, Val, Met, Phe, and Leu contents of egg. The plasma antioxidant status and immune response improved by dietary addition of HILM at 3% levels.

The addition of Hermetia illucens larvae meal (HILM) to the feed could contribute to particular antimicrobial and intestinal health in animal husbandry. This study was conducted to investigate the effects of HILM on intestinal morphology and microbial diversity in different intestinal segments of Xuefeng black-bone chickens. All of 432 birds (45 weeks old) were randomly assigned to four equal groups with six replicates and 18 hens in each replicate: (A) basal diet, (B) basal diet with 1% HILM, (C) basal diet with 3% HILM, and (D) basal diet with 5% HILM. The results showed that, compared with the basal diet group, the HILM supplement significantly increased the abundance-based coverage estimator (ACE) and Chao index in cecum (p &lt; 0.05). Diet with 1% HILM significantly increased the villus height (VH) of the duodenum (p &lt; 0.05) and cecum microbial diversity as represented by the Simpson index (p &lt; 0.05). In particular, 1% HILM displayed a markedly increase in the genus unclassified Bacteroidales (cecum, p &lt; 0.05). A basal diet with 3% HILM markedly increased the beneficial genus Romboutsia (jejunum, p &lt; 0.05). Also, principal component analysis (PCA) cluster analysis showed that 3% of HILM was more individual than other groups (p &lt; 0.05). However, 5% HILM decreased the VH and the ratio of villus height to crypt depth (VH/CD) of the jejunum and increased beneficial bacteria such as Staphylococcus (p &lt; 0.05), which was regarded as pathogenetic genera. In conclusion, we found that HILM improved intestinal morphology and increased microbiological diversity and species abundance. Together, dietary supplementation of 1 or 3% HILM might benefit the intestinal morphology and intestinal microbiota of Xuefeng black-bone chicken. However, the addition of 5% HILM could decrease VH and the ratio of VH/CD of the jejunum and increased pathogenetic genera. HILM was an excellent protein substitute for Xuefeng black-bone chickens, which could meet the nutritional requirements under the condition of less feed. These results provide information for HILM meal as an alternative source of soybean meal in Xuefeng black-bone chickens’ feed.

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