METHODS: A systematic literature search was performed in Scopus, Embase, Web of Science, and PubMed databases up to February 2020 for RCTs that investigated the effect of DHEA supplementation on testosterone levels. The estimated effect of the data was calculated using the weighted mean difference (WMD). Subgroup analysis was performed to identify the source of heterogeneity among studies.
RESULTS: Overall results from 42 publications (comprising 55 arms) demonstrated that testosterone level was significantly increased after DHEA administration (WMD: 28.02 ng/dl, 95% CI: 21.44-34.60, p = 0.00). Subgroup analyses revealed that DHEA increased testosterone level in all subgroups, but the magnitude of increment was higher in females compared to men (WMD: 30.98 ng/dl vs. 21.36 ng/dl); DHEA dosage of ˃50 mg/d compared to ≤50 mg/d (WMD: 57.96 ng/dl vs. 19.43 ng/dl); intervention duration of ≤12 weeks compared to ˃12 weeks (WMD: 44.64 ng/dl vs. 19 ng/dl); healthy participants compared to postmenopausal women, pregnant women, non-healthy participants and androgen-deficient patients (WMD: 52.17 ng/dl vs. 25.04 ng/dl, 16.44 ng/dl and 16.47 ng/dl); and participants below 60 years old compared to above 60 years old (WMD: 31.42 ng/dl vs. 23.93 ng/dl).
CONCLUSION: DHEA supplementation is effective for increasing testosterone levels, although the magnitude varies among different subgroups. More study needed on pregnant women and miscarriage.
METHODS: This study innovatively explores the potential of H. illucens larvae (HIL) protein as a peptone substitute for microbial culture media. Four commercial proteases (alkaline protease, trypsin, trypsase, and papain) were explored to hydrolyze the defatted HIL, and the experimental conditions were optimized via response surface methodology experimental design. The hydrolysate of the defatted HIL was subsequently vacuum freeze-dried and deployed as a growth medium for three bacterial strains (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli) to determine the growth kinetics between the HIL peptone and commercial peptone.
RESULTS: The optimal conditions were 1.70% w/w complex enzyme (alkaline protease: trypsin at 1:1 ratio) at pH 7.0 and 54 °C for a duration of 4 h. Under these conditions, the hydrolysis of defatted HIL yielded 19.25% ±0.49%. A growth kinetic analysis showed no significant difference in growth parameters (μmax, Xmax, and λ) between the HIL peptone and commercial peptone, demonstrating that the HIL hydrolysate could serve as an effective, low-cost alternative to commercial peptone. This study introduces an innovative approach to HIL protein resource utilization, broadening its application beyond its current use in animal feed.
New information: Five species are new records for Malaysia (Ctenogobiops mitodes, Epibulus brevis, Halichoeres erdmanni, H. richmondi and Scarus caudofasciatus) and 25 species are newly recorded in the Redang archipelago.