Zinc-enriched Probiotic Preparations Promote the Growth and Development of Zinc-deficient Rats and the Effect on Mineral Absorption

Objective: To investigate the effects of zinc-enriched probiotic preparations on the growth and development of zinc-deficient rats and the expression of transporter genes related to zinc and calcium mineral absorption. Methods: Thirty-six 3-week-old SD rats were randomly divided into six groups, including a blank control group, a zinc-deficient model group, and four intervention groups, with a 21-day experimental period. Observed apparent indicators in rats, Micro-CT for detecting femoral bone density and trabecular number, assay kits for measuring serum levels of growth hormone (GH), insulin-like growth factor-1 (IGF-1), and testosterone (T), biochemical analyzer for detecting serum zinc and alkaline phosphatase (ALP) levels, and RT-qPCR method for detecting gene expression levels of zinc transport proteins (Znt1, Znt2, Zip4) and vitamin D receptor (Vdr) in small intestine tissue. Results: The zinc-enriched probiotic formulation significantly increased food intake, body weight, and femoral weight in rats (P<0.001), elevated serum zinc levels and alkaline phosphatase (ALP) activity (P<0.0001), and enhanced the levels of growth-related hormones such as growth hormone (GH), insulin-like growth factor-1 (IGF-1), and testosterone (T) (P<0.01, P<0.05, P<0.0001), thereby comprehensively promoting growth and development. It regulated the expression of zinc transport protein genes in the small intestine to maintain systemic zinc homeostasis and upregulated the expression of the calcium absorption-related gene vitamin D receptor (Vdr) mRNA (P<0.0001) to facilitate calcium absorption. Conclusion: The zinc-enriched probiotic preparation can promote the growth and development of zinc-deficient rats, enhance the absorption of zinc and calcium, and alleviate bone development disorders caused by zinc deficiency. The effect of zinc-enriched probiotic is better than that of zinc gluconate in the absorption and utilization of zinc and the regulation of hormones related to growth and development.