Response of blood biochemical metabolites, ruminal fermentation, and bacterial genetic diversity to chitosan supplementation in goats

Chitosan is a feed additive with multiple potential benefits for ruminant digestion, fermentation, and overall animal performance. This study evaluated the effects of dietary chitosan supplementation on serum metabolites, characteristics, and rumen microbial communities in Jabal Akhdar goats using 16S rRNA gene sequencing. Sixteen female goats (33.0 ± 2.5 kg body weight) were randomly assigned to two treatment groups (n = 8) in a completely randomized design. The control group received a basal diet, whereas the chitosan group was fed the basal diet supplemented with 360 mg chitosan/kg concentrate diet. Blood samples and rumen digesta were collected individually at 3 h post-morning feeding on days 14, 28, and 42 to assess serum biochemical metabolites, rumen fermentation parameters, and rumen microbial composition. In goats supplemented with chitosan, serum total protein (P = 0.023) and albumin (P < 0.001) concentrations were significantly increased, whereas blood urea nitrogen was markedly reduced (P < 0.001), with a tendency toward higher glucose concentrations (P = 0.070). Chitosan supplementation also decreased ruminal NH₃-N (P = 0.001) and total volatile fatty acid concentrations (P = 0.014), as well as acetate (P < 0.001), butyrate (P = 0.025), and the acetate-to-propionate ratio (P < 0.001), while increased propionate concentration (P = 0.004). Furthermore, chitosan altered the rumen bacterial composition. The relative abundance of the Chloroflexi phylum was higher (P = 0.012) in goats supplemented with chitosan, whereas Bifidobacterium merycicum relative abundance was reduced (P = 0.001) compared with the control group. In addition, the relative abundances of Actinobacteria (P = 0.063) and Tenericutes (P = 0.094) tended to increase in the rumen of chitosan-supplemented goats. These results indicate that supplementation with 360 mg chitosan/kg concentrate diet beneficially modulated the rumen bacterial community by enhancing propiogenesis, thereby improving feed fermentability and energy efficiency without compromising goat health.