Background: This in vitro study aimed to compare the hindgut fermentability and digestibility of four different sources of polyphenols, namely orange (Citrus sinensis) peel (ORP), pomegranate (Punica granatum) peel (PMP), Indian blackberry (Syzygium cumini) pulp (IBP), and Jerusalem artichoke (Helianthus tuberosus) tuber (JAT), and their influence on the viability of a canine-origin probiotic, Lactobacillus johnsonii CPN23.
Results: An in vitro gas production test carried out using the four substrates for a period of 72 h with dog faecal inoculum indicated that the total gas production, dry matter, and organic matter digestibility were significantly (P < 0.001) higher with JAT, whereas they were lowest for PMP. Short-chain fatty acids production was significantly higher (P < 0.001) with ORP and JAT, with the least values recorded for PMP. The ammonia-nitrogen production was significantly (P < 0.001) higher with JAT than with ORP, IBP, and PMP, and a lower (P < 0.001) pH was evident with ORP, JAT, and IBP than with PMP. Viability of L. johnsonii CPN23 was tested in the presence of the polyphenol-rich extract from each of the four sources at varying doses (50, 500, 1000, 2500, and 5000 μg mL-1 ). PMP extract showed the highest inhibitory effect on the probiotic bacteria's growth in a dose- and time-dependent manner (P < 0.001). ORP and IBP extracts were stimulatory at the optimum dosage, whereas JAT reduced probiotic activity significantly at all doses tested.
Conclusion: Overall, the results indicate a higher hindgut fermentability of JAT, ORP, and IBP, suggesting their potential beneficial effects for gut health application. An interaction study between polyphenol extract and L. johnsonii CPN23 showed a stimulatory effect of polyphenolic extracts from ORP and IBP on probiotic growth at optimal dosage. Consistent with the fermentation study findings, PMP extract reduced the growth of L. johnsonii CPN23 irrespective of the doses tested. © 2021 Society of Chemical Industry.
Keywords: fermentation; fruit by-products; hindgut; interaction; polyphenols; probiotic.
© 2021 Society of Chemical Industry.