Early weaned piglets are vulnerable to diarrhea because of weaning stress and immaturity of intestinal tract. Compelling evidence suggests that gut microbiota is vital to host health. However, it is not well understood on the composition and succession of piglet gut microbiota during the weaning transition. In our two trials, total 17 commercial piglets were studied in a pig farm in Jiangxi Province, China. Fresh feces were collected for four times (10 days before weaned, weaned day, 10 days after weaned, 21 days after weaned) by rectal massage. Fecal bacterial composition was assessed by 16S rRNA gene V3–V4 regions sequencing by Illumina Miseq platform. The results showed that the gut microbiota of piglets shifted quickly after weaned and reached relatively stable level in 10 days after weaned. The alpha diversity increased significantly with the age of piglets. The microbiota of suckling piglets was mainly represented by Fusobacterium, Lactobacillus, Bacteroides, Escherichia/Shigella, and Megasphaera. This pattern contrasted with that of Clostridium sensu stricto, Roseburia, Paraprevotella, Clostridium XIVa, and Blautia, which were major representative genera after weaned. In summary, we delineated the development of piglet gut microbiota during the weaning transition. This study helps us understand the maturing development of gut microbiota in commercial piglets.
Astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione), a high-value ketocarotenoid with a broad range of applications in food, feed, nutraceutical, and pharmaceutical industries, has been gaining great attention from science and the public in recent years. The green microalgae Haematococcus pluvialis and Chlorella zofingiensis represent the most promising producers of natural astaxanthin. Although H. pluvialis possesses the highest intracellular astaxanthin content and is now believed to be a good producer of astaxanthin, it has intrinsic shortcomings such as slow growth rate, low biomass yield, and a high light requirement. In contrast, C. zofingiensis grows fast phototrophically, heterotrophically and mixtrophically, is easy to be cultured and scaled up both indoors and outdoors, and can achieve ultrahigh cell densities. These robust biotechnological traits provide C. zofingiensis with high potential to be a better organism than H. pluvialis for mass astaxanthin production. This review aims to provide an overview of the biology and industrial potential of C. zofingiensis as an alternative astaxanthin producer. The path forward for further expansion of the astaxanthin production from C. zofingiensis with respect to both challenges and opportunities is also discussed.
An HPLC method, for the simultaneous determination of the degradation products of ascorbic acid,
was employed to investigate the degradation of ascorbic acid in aqueous solution at different pH
values. After ascorbic acid aqueous solutions were heated at 100 °C for 2 h, four main degradation
products, furfural, 2-furoic acid, 3-hydroxy-2-pyrone, and an unidentified compound, were separated
and determined. In an acid aqueous solution, ascorbic acid was converted to 2-furoic acid and
3-hydroxy-2-pyrone via dehydroascorbic acid under aerobic conditions, whereas under anaerobic
conditions, ascorbic acid degraded to furfural. Low pH conditions favored the formation of furfural,
2-furoic acid, and 3-hydroxy-2-pyrone; at extremely low pH (i.e., pH 1), the formation of furfural
dominated. In an alkaline aqueous solution, the unknown compound became the main degradation
product of ascorbic acid; at pH 10, only very small amounts of furfural and 3-hydroxy-2-pyrone
with no 2-furoic acid were detected. Our results suggest that, in a hydrogen-ion-catalyzed
environment, the anaerobic degradation of ascorbic acid to furfural is the main degradation pathway
in an aqueous solution.
Keywords: Ascorbic acid; dehydroascorbic acid; degradation; furfural; 2-furoic acid; 3-hydroxy-2-pyrone; HPLC
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