Eighteen lactating goats (38.86 ± 2.06 kg) were randomly allocated to three groups. One group was fed a low-concentrate (LC) diet (forage:concentrate = 6:4), while the other two groups were fed a high-concentrate (HC) diet (forage:concentrate = 4:6) or an HC diet supplemented with sodium butyrate (BHC) for 20 weeks. Samples of ruminal fluid, milk, hepatic blood plasma, and mammary gland tissue were prepared for the experimental analysis. The lipopolysaccharide (LPS) concentration, caspase-3 and -8 enzymatic activity, caspase-3 and -8 mRNA expression, and NF-κB (p65), phosphorylated-p65, bax, cytochrome c, and caspase-3 protein expression were higher in the HC group than those in the LC group; however, the levels of these parameters were lower in the BHC group than those in the HC group. Moreover, bcl-2 mRNA and protein expression was higher in the BHC group than that in the HC or LC groups, and no significant difference was observed between the HC and LC groups. Thus, feeding lactating goats an HC diet induces apoptosis in mammary cells, and supplementing the diet with sodium butyrate reduces the concentrations of LPS and proinflammatory cytokines, subsequently attenuating the activation of NF-κB and caspase-3 and eventually inhibiting apoptosis in mammary cells.
Keywords: NF-κB; dairy goats; high concentrate; mammary cell apoptosis; sodium butyrate.