Carotenoids are the most abundant lipid-soluble phytochemicals and are used as dietary supplements to protect against diseases caused by oxidative stress. Astaxanthin, a xanthophyll carotenoid, is a very potent antioxidant with numerous beneficial effects on cellular functions and signaling pathways. In this study, using spleen cells from healthy Balb/c mice, we report the bio-functional effects of an astaxanthin-rich extract (EXT) prepared from the microalga Haematococcus pluvialis and its astaxanthin monoesters-rich fraction (ME) and astaxanthin diesters-rich fraction (DE) obtained by fractionation of EXT using countercurrent chromatography (CCC). After incubation under standard culture conditions (humidity, 37 °C, 5% CO2, atmospheric oxygen), the viability of untreated splenocytes, as determined by the trypan blue exclusion assay, the MTT assay, and the neutral red assay, decreases to approximately 75% after 24 h compared with naïve splenocytes. This effect correlated with the decrease in mitochondrial membrane potential and the transition of ~59% of cells to the early stage of apoptosis, as well as with the decreased ROS production, indicating that hyperoxia in cell-culture deteriorates cell functions. They are restored or stimulated by co-cultivation with EXT, ME, and DE up to 10 μg/mL in the order EXT > DE > ME, suggesting that esterification increases bioavailability to cells in vitro. ROS and H2O2 concentrations reflect mRNA transcriptional activity of Nrf2, superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 1, as well as SOD-mediated ROS conversion, whereas they inversely correlate with iNOS-mediated NO production. The highest-tested concentration of EXT, ME, and DE (40 μg/mL) is detrimental to cells, probably because of the overwhelming scavenging activity of astaxanthin and its esters for the reactive oxygen/nitrogen species required for cellular functions and signal transduction at low physiological concentrations. In this study, we demonstrate that differential activities of ME and DE contribute to the final antioxidant and cytoprotective effects of astaxanthin extract, which is beneficial in preventing a wide range of ROS-induced adverse effects, with DE being more effective. In addition, the selection of physioxia-like conditions for pharmacological research is highlighted.
- Publikační typ
- časopisecké články MeSH
Výskum probiotík pre akvakultúru je v ranom štádiu a pre ich implementáciu je potrebné vykonať ešte množstvo experimentov. Laktiplantibacily patria medzi mikroorganizmy, ktoré sa najčastejšie používajú na prípravu probiotických preparátov. Doterajšie výsledky nie sú postačujúce, práve preto sú potrebné ďalšie štúdie. Výber probiotík pre akvakultúru a ich vývoj pre komerčné využitie v akvakultúre je mnohostupňový a multidisciplinárny proces vyžadujúci si v prvej etape základný a neskôr aj aplikovaný výskum a posúdenie jeho použitia v praxi. Cieľom štúdie bolo pripraviť probiotické krmivo pre ryby s využitím pomocných látok a následne sledovať prežívateľnosť probiotických bakteriálnych buniek v krmive počas 9-mesačného skladovania pri chladničkovej (4 °C) a izbovej teplote (22 °C). Na prípravu krmiva bol použitý kmeň Lactobacillus plantarum R2 Biocenol™ (CCM 8674) (podľa novej taxonómie Lactiplantibacillus plantarum), potenciálne využiteľný pre probiotické účely v akvakultúre. Lepšia prežívateľnosť probiotických bakteriálnych buniek bola zaznamenaná vo vzorkách krmiva A (Aquatex 41 HMD) v porovnaní so vzorkami probiotických peliet B (Inicio 918-2). Keďže oxidácia mastných kyselín v krmive ovplyvňuje nutričnú kvalitu jednotlivých komponentov krmiva, predpokladáme, že vyššie množstvo oleja v krmive B negatívne ovplyvnilo prežívateľnosť probiotických bakteriálnych buniek. Najvyššie počty životaschopných probiotických baktérií boli zaznamenané pri 4 °C skladovania krmiva. Po 9 mesiacoch skladovania pri chladničkovej teplote počty laktiplantibacilov vo vzorkách krmiva A klesli z hodnoty 7,30 log10KTJ/g na počet 5,57 log10KTJ/g. Teplota je považovaná za rozhodujúci faktor ovplyvňujúci životaschopnosť a prežívateľnosť probiotických baktérií počas doby skladovania.
Research in probiotics for aquaculture is at an early stage of development and much work is still needed. Lactiplantibacilli belong to the microorganisms most frequently used to prepare the probiotics. The available information is inconclusive, since few experiments with sufficiently robust design have been conducted to permit critical evaluation. The development of probiotics applicable to commercial use in aquaculture is a multistep and multidisciplinary process requiring both empirical and fundamental research, full-scale trials, and an economic assessment of its use. The aim of the study was to prepare a probiotic aquafeed via excipients and subsequently to observe the survival of probiotic bacterial cells in the feed during the nine months storage period at a refrigerator (4 °C) or room temperature (22 °C). The strain Lactobacillus plantarum R2 Biocenol™ (CCM 8674) (according to the new taxonomy Lactiplantibacillus plantarum), potentially usable as a probiotic in aquaculture, was administered to prepare the aquafeed. Better survival of probiotic bacterial cells was recorded in a samples of pellets A (Aquatex 41 HMD) compared to the samples of probiotic pellets B (Inicio 918-2). Since oxidation of fatty acids in feed affects the nutritional quality of individual feed components, we assume that higher amounts of oil in feed B negatively affected the survival of probiotic bacterial cells. The highest numbers of viable probiotic bacteria cells were recorded at 4 °C storage of probiotic feed samples. The number of lactiplantibacilli dropped from 7.30 log10CFU . g–1 to 5.57 log10CFU . g–1 after the nine months storage period of feed samples A at 4 °C. Temperature is considered as a critical factor influencing probiotic viability and survival during storage period.
