The Addition of Hot Water Extract of Juncao-Substrate Ganoderma lucidum Residue to Diets Enhances Growth Performance, Immune Function, and Intestinal Health in Broilers

The purpose of this experiment was to investigate the effects of Hot Water Extract of Juncao-substrate <i>Ganoderma lucidum</i> Residue (HWE-JGLR) on the immune function and intestinal health of yellow-feather broilers. In an animal feeding experiment, 288 male yellow-feather broilers (1 day old) were randomly allocated to four treatment groups with six replicates of 12 birds each. The control (CON) group was fed a basal diet. HJ-1, HJ-2, and HJ-3 were fed a basal diet supplemented with 0.25%, 0.50%, and 1.00% HWE-JGLR, respectively. The feeding trial lasted for 63 d. The results showed increased ADFI (<i>p</i> = 0.033) and ADG (<i>p</i> = 0.045) of broilers in HJ-3, compared with the CON group. Moreover, higher contents of serum IL-4 and IL-10 and gene expression of IL-4 and IL-10 in jejunum mucosa and lower contents of serum IL-1β and gene expression of IL-1β in jejunum mucosa in HJ-3 were observed (<i>p</i> < 0.05). Additionally, the jejunal mucosal gene expression of <i>Claudin-1</i> and <i>ZO</i>-<i>1</i> in HJ-2 and HJ-3 was higher than that in the CON group (<i>p</i> < 0.05). As for the microbial community, compared with the CON group, the ACE index, Shannon index, and Shannoneven index of cecal microorganisms in HJ-2 and HJ-3 were elevated (<i>p</i> < 0.05). PCoA analysis showed that the cecal microbial structure of broilers in HJ-2 and HJ-3 was different from the CON group (<i>p</i> < 0.05). In contrast with the CON group, the broilers in HJ-2 and HJ-3 possessed more abundant Desulfobacterota at the phylum level and <i>unclassified Lachnospiraceae</i>, <i>norank Clostridia vadinBB60 group</i> and <i>Blautia</i> spp. at the genus level, while <i>Turicibacter</i> spp. and <i>Romboutsia</i> spp. were less (<i>p</i> < 0.05). In conclusion, dietary supplementation with HWE-JGLR can improve growth performance, enhance body immunity and intestinal development, and maintain the cecum microflora balance of yellow-feather broilers.