“In this study, we selected a peptide from fish (tilapia) skin that induces significant changes in the intestinal microflora of mice and reduces the Firmicutes/Bacteroidetes ratio, which is linked to obesity,” the team of South Korean researchers wrote in the journal Nutrients.
Given the known associations of gut microbiota dysbiosis with diseases ranging from inflammatory bowel disease, Crohn’s disease, and ulcerative colitis to type 2 diabetes, autoimmune diseases and behavioral disorders, the researchers asserted that “consumption of probiotics or prebiotics has more value as a therapeutic agent than just a nutritional supplement”.
To this end, they present the study in the context of developing a gut microbiota-based screening strategy to select nutritional supplements as prebiotic medications.
Study details
The study randomly assigned eight-week-old male C57BL/6 mice fed a high-fat diet to one of six different peptide groups (fish collagen, soybean type A, B, and yeast type A, B, C) or a distilled water control group. Mice consumed 100 μL of their alloted substance by gavage daily over the 10-day study period.
For the gut microbiota analyses, the researchers collected feces on the third and seventh day after peptide treatment and sacrificed the mice on the tenth day to remove their intestines for further investigation. The analysis of fecal samples revealed that Bacteroidetes and Firmicutes accounted for close to 90% of the total microbiota in all treatment groups.
“Interestingly, compared with the control group, fish collagen-derived peptides significantly decreased the F/B ratio, whereas other peptides did not affect this ratio,” the researchers wrote.
The collagen peptide treatment increased the abundance of Bacteroidetes to 64% and decreased Firmicutes to 31% in the gut compared with the control group (38% and 54%, respectively). Other increases in specific bacterial taxa detected in the collagen peptide group: Clostridium_sensu_stricto_1, Faecalibaculum, Bacteroides, and Streptococcus, known for their anti-obesity effects.
The anti-obesity effects
The researchers noted that since collagen peptide consumption demonstrated significant reduction in the F/B ratio in normal mice, its anti-obesity effect was expected.
“Early research on the relationship between obesity and gut microbiota established that significant fractions of intestinal Bacteroidetes and Firmicutes are altered in obese mice compared with those in lean mice,” they wrote.
Beyond the changes to the composition of the gut microbiota, the study found that the alterations led to activation of metabolic pathways, such as polysaccharide degradation and essential amino acid synthesis, which are associated with obesity inhibition.
“[C]ollagen peptide also effectively reduced all obesity signs caused by a high-fat diet, such as abdominal fat accumulation, high blood glucose levels, and weight gain,” the researchers added, specifying that mice in the collagen peptide group gained considerably less weight than mice fed a high-fat diet alone.
Source: Nutrients 2023, 15(11), 2610
“Collagen Peptide Exerts an Anti-Obesity Effect by Influencing the Firmicutes/Bacteroidetes Ratio in the Gut”
doi: doi.org/10.3390/nu15112610
Authors: Ga Hyeon Baek et al.
