Effects of dietary biotin supplementation on glucagon production, secretion, and action

Revised D-A-CH reference values for the intake of biotin

Purpose

The reference values for biotin intake for Germany, Austria and Switzerland lead back to a report in 2000. Following a timely update process, they were revised in 2020.

Methods

For infants aged 0 to < 4 months, adequate biotin supply via human milk was assumed and in consequence the reference value reflects the amount of biotin delivered by human milk. For infants aged 4 to < 12 months, biotin intake was extrapolated from the reference value for younger infants. Due to missing data on average requirement, the reference values for biotin intake for children, adolescents and adults were derived based on observed intake levels. The reference value for lactating women considered in addition biotin losses via human milk.

Results

The reference value for biotin intake for infants aged 0 to < 4 months was set at 4 µg/day and for infants aged 4 to < 12 months at 6 µg/day. In children and adolescents, the reference values for biotin intake ranged from 20 µg/day in children 1 to < 4 years to 40 µg/day in youths 15 to < 19 years. For adults including pregnant women, 40 µg/day was derived as reference value for biotin intake. For lactating women, this value was set at 45 µg/day.

Conclusions

As deficiency symptoms of biotin do not occur with a usual mixed diet and the average requirement cannot be determined, reference values for an adequate biotin intake for populations from Germany, Austria and Switzerland were derived from biotin intake levels assessed in population-based nutrition surveys.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02756-0.

Dietary Supplementation with Enterococcus faecium R1 Attenuates Intestinal and Liver Injury in Piglets Challenged by Lipopolysaccharide

Simple Summary

The biological characteristics of E. faecium R1 and the effect of dietary supplementation with E. faecium R1 on the growth performance of weaned piglets were studied. The results showed that E. faecium R1 had the characteristics of effective bacteriostatic activity, acid resistance, bile salt resistance, and high-temperature resistance. Dietary supplementation with E. faecium R1 (6.5 × 10⁶ CFU/g) improved intestinal function of weaning piglets by decreasing diarrhea incidence. Further research found that dietary supplementation with E. faecium R1 (6.5 × 10⁶ CFU/g) attenuated intestinal and liver injury in piglets challenged by lipopolysaccharide.

Abstract

In this study, a strain of E. faecium R1 with effective bacteriostatic activity, acid resistance, bile salt resistance, high-temperature resistance was screened. To study the effect of E. faecium R1 on lipopolysaccharide (LPS)-induced intestinal and liver injury in piglets, twenty-four weaned female piglets were randomly assigned into one of three groups (8 piglets per group). Piglets in the control group and LPS group were fed a basal diet, piglets in the E. faecium group were fed the basal diet supplemented with E. faecium R1 (6.5 × 10⁶ CFU/g). On day 21 of the trial, piglets in the LPS group and E. faecium group were intraperitoneally administered LPS (100 μg/kg), piglets in the control group were administered the same volume of saline. Subsequently, blood samples were collected at 3 h, and intestinal, liver, and pancreas samples were collected at 6 h. Results showed that E. faecium R1 supplementation significantly decreased the diarrhea rate and feed to gain ratio, and dramatically reduced LPS-induced intestinal and liver injury in piglets. Compared with the LPS group, E. faecium R1 supplementation significantly increased the content of glucagon in plasma and IL-1β in the liver, and the mRNA levels of villin in jejunum and ileum and Bcl-xL and pBD-L in the ileum, and significantly decreased the contents of prostaglandin 2 and malondialdehyde in the liver and the activities of myeloperoxidase and aspartate aminotransferase in plasma in piglets. Moreover, E. faecium R1 improved the pancreatic antioxidant capacity in piglets, which was indicated by a significant increase in catalase activity and a decrease in total nitric oxide synthase activity. In summary, dietary supplementation with E. faecium R1 alleviates intestinal and liver injury in LPS-challenged piglets.

Dietary Biotin Supplementation Impairs Testis Morphology and Sperm Quality

Supplements containing pharmacological concentrations of biotin are commercially available over the counter. Classical toxicity studies have considered biotin administration as harmless; however, recent investigations have shown that biotin supplementation modifies tissue morphology without changes in toxicity markers, raising concerns about the consequences of morphological changes on tissues' functions and the safety of pharmacological concentrations of the vitamin. Testes are very sensitive to toxicants, and testicular histology is a reliable method to study its function. In this work, we investigated the effects of dietary biotin supplementation on testis morphology and spermatogenesis function using an experimental model, in which we have not observed unfavorable effects on other tissue functions or toxicity markers. Male BALB/cAnNHsd mice were fed a control or a biotin-supplemented diet (1.76 or 97.7 mg biotin/kg diet) for 8 weeks. Compared to the control group, the biotin-supplemented mice presented remarkable testis morphology changes, including increased spermatogonia layers; the cellular mechanism involved is related to increased proliferation. Sperm count and serum testosterone levels were not affected, but spermatozoa motility and morphology were significantly impaired in the biotin-supplemented mice. These results caution against the use of supplements with high concentrations of biotin and indicate that biotin's pharmacological effects on morphology need to be considered in toxicological studies.