Heat inactive Bacillus subtilis var. natto regulate Nile tilapia (Oreochromis niloticus) intestine microbiota and metabolites involved in the intestine phagosome response.

In this study, we evaluated the intestinal microbiota, intestinal and fecal metabolites production and the intestinal RNA-seq analysis of the Nile tilapia intestine after feeding with 105and 107 of the inactive Bacillus subtilis var. natto. First, we assessed the influence of heat inactive Bacillus subtilis var. natto on the growth performance, biochemical blood analysis, and evaluated the liver/body, spleen/body and intestine/body ratio. This evidence was known feeding with inactive Bacillus subtilis var. natto was able to improve the growth performance after 4 weeks, but not to affect the inflammatory biochemical blood parametres total protein (T-pro), albumin (Alb), Alb/T-pro ratio, creatine-phospho-kinase (CPK) and lactate dehydrogenase (LDH). Further, in the intestine microbiota, the Lactobacillaceae, Firmicutes, Chromatiales, and Rhodobacteria, was significantly higher than the control and the Firmicutes/Bacteroidetes ratio (F/B), which was indicated with a significantly increased. The intestine tissue metabolites OPLS-DA analysis indicated that the prominent bioactive metabolites changed. The peonidin-3-glucoside, l-Tyrosine, 1-Deoxy-1-(N6-lysino)-d-fructose was significantly increased. The feces metabolite OPLS-DA analysis indicated that the palmitelaidic acid, 5-KETE, tangeritin was significantly increased. In the transcriptome, the Gene Ontology (GO) analysis was found to enhance the intestine intestinal immune network. Combine of these evidence, feeding of the heat inactive Bacillus subtilis var. natto exactly improved the O. niloticus growth performance and regulation of the microbiota to promote the metabolites. In the transcriptome analysis, it was found to involve in the intestine immune phagosome response. Summarized of this study, the heat inactive Bacillus subtilis var. natto was reported to affect Nile tilapia intestine microbiota, and could positively regulate the intestine and fecal metabolites production to improve the intestine immune network.

Red Algae "Sarcodia suieae" Acetyl-Xylogalactan Downregulate Heat-Induced Macrophage Stress Factors Ddit3 and Hyou1 Compared to the Aquatic Animal Model of Nile Tilapia (Oreochromis niloticus) Brain Arachidonic Acid Expression

Anthropogenic climate change is known to be an increased stress that affects aquatic animal behavior and physiological alternations, which can induce the animal's death. In order to known whether the extracted acetyl-xylogalactan function on the regulation of the external high temperature induced death, we first selected the mammalian cell line "RAW 264.7" used in the previous experiment to evaluate the extracted acetyl-xylogalactan function. We aimed to evaluate the effects of the acetyl-xylogalactan on the RAW 264.7 macrophages and Nile Tilapia stress factor expression under the heat environment. In the in vitro cell observation, we assessed the cell survival, phagocytic activity, intracellular Ca2+ level, mitochondria potential exchange, apoptotic assay findings, galactosidase activity, RNA-seq by NGS and real-time polymerase chain reaction (QPCR) expression. In the in vivo Nile Tilapia observation aimed to evaluate the blood biochemical indicator, brain metabolites exchange and the liver morphology. In our evaluation of RAW 264.7 macrophages, the RNA sequencing and real-time polymerase chain reaction (PCR) was shown to upregulate the expression of the anti-apoptosis Cflar gene and downregulate the expression of the apoptosis factors Ddit3 and Hyou1 to protect macrophages under heat stress. We already knew the extracted acetyl-xylogalactan function on the mammalian "RAW 264.7" system. Following, we used the aquatic Nile Tilapia model as the anthropogenic climate change high temperature experiment. After feeding the Nile Tilapia with the acetyl-xylogalactan, it was found to reduce the brain arachidonic acid (AA) production, which is related to the NF-κB-induced apoptosis mechanism. Combined with the in vitro and in vivo findings, the acetyl-xylogalactan was able to reduce the heat induced cell or tissue stress.

Acid external and internal environment exchange the Oreochromis niloticus tissue immune gene expression compared to the mouse macrophage polarization model.

The water environment plays an important role in animal physiology. In this study, we sought to evaluate the effect of the acid environment on the Oreochromis niloticus (Nile tilapia) internal microenvironment immune response compare to the mouse macrophage model (J77A.1). The acid environment treated mouse macrophage J774A.1 model have shown that acidic treatment is able to polarize macrophages into M2-like macrophages via an increase in Ym1, Tgm2, Arg1, Fizz1, and IL-10 expression. Metabolic analysis of mouse macrophages (J774A.1) at pH 2 vs. pH 7 and pH 4 vs. pH 7 have been shown to promote the expression of intracellular acetylcholine, choline, prochlorperazine, L-leucine, and bisphenol A,2-amino-3-methylimidazo[4,5-f] quinolone metabolites in the M2-like macrophage. Immune gene expression of the O. niloticus spleen and liver treated at pH 2, 4, and 7 was shown to reduce TNF-α, IL-1 ß, IL-8, and IL-12 expression compared to pH 7 treatment. Immune gene was induced in O. niloticus following culture at pH 5, 6, and 7 fresh water environment. Taken together, we found that the acid internal environment polarizes tissues into an M2 macrophage developmental microenvironment. However, if the external environment is acid, tissues are exposed to an M1 macrophage developmental microenvironment.