MHC II-PI3K/Akt/mTOR Signaling Pathway Regulates Intestinal Immune Response Induced by Soy Glycinin in Hybrid Grouper: Protective Effects of Sodium Butyrate

Abstract

Soy glycinin (11S) is involved in immune regulation. As an additive, sodium butyrate (SB) can relieve inflammation caused by 11S. To further delve into the mechanisms. A diet containing 50% fishmeal was the control group (FM group), and the experimental groups consisted of the FM group baseline plus 2% glycinin (GL group), 8% glycinin (GH group), and 8% glycinin + 0.13% sodium butyrate (GH-SB group). The specific growth ratio (SGR), feed utilization, and density of distal intestinal (DI) type II mucous cells were increased in the GL group. In the serum, IFN-γ was significantly upregulated in the GL group, and IgG and IL-1β were upregulated in the GH group. IgG, IL-1β, and TNF-α in the GH-SB group were significantly downregulated compared to those in the GH group. The mRNA levels of mTOR C1, mTOR C2, and Deptor were upregulated in the GL, GH, and GH-SB groups in the DI compared with those in the FM group, while the mRNA levels of mTOR C1 and Deptor in the GH group were higher than those in the GL and GH-SB groups. 4E-BP1, RICTOR, PRR5, MHC II, and CD4 were upregulated in the GH group. TSC1, mLST8, and NFY mRNA levels in the GL and GH-SB groups were upregulated compared with those in the FM and GH groups. Western blotting showed P-PI3KSer294/T-PI3K, P-AktSer473/T-Akt, and P-mTORSer2448/T-mTOR were upregulated in the GH group. Collectively, our results demonstrate that low-dose 11S could improve serum immune by secreting IFN-γ. The overexpression of IgG and IL-1β is the reason that high-dose 11S reduces serum immune function, and supplementing SB can suppress this overexpression. Low-dose 11S can block the relationship between PI3K and mTOR C2. It can also inhibit the expression of 4E-BP1 through mTOR C1. High-dose 11S upregulates 4E-BP2 through mTOR C1, aggravating intestinal inflammation. SB could relieve inflammation by blocking PI3K/mTOR C2 and inhibiting 4E-BP2. Generally speaking, the hybrid grouper obtained different serum and DI immune responses under different doses of 11S, and these responses were ultimately manifested in growth performance. SB can effectively enhance serum immunity and relieve intestinal inflammation caused by high dose 11S.

Supplementing tributyrin to cottonseed protein concentrate‐based diets can improve growth performance, lipid metabolism and distal intestinal immunity in hybrid grouper ( Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

“…According to the results in Figure 2, at least 0.04% tributyrin should be supplemented to the feed to significantly improve the disease resistance of hybrid grouper. In addition, the slow release of butyric acid from tributyrin in the intestine could enhance the intestinal barrier, whilst it can supply energy to the intestinal epithelial cells and enhance host immunity (Yin et al, 2021). This may also be related to enhancing disease resistance in hybrid grouper.…”

Sinomenine Hydrochloride Ameliorates Fish Foodborne Enteritis via α7nAchR-Mediated Anti-Inflammatory Effect Whilst Altering Microbiota Composition

“…As fishmeal remains an important source of dietary protein in aquaculture diets, its increasing price and decreasing availability have given birth to a replacement of feed made from plant sources of dietary protein, such as soybean meal ( 1 ). The side effects resulting from plant-sourced proteins have occurred in many fish species, from carnivorous to herbivorous, such as salmon ( 2 ), grouper ( 3 ), zebrafish ( 4 , 5 ), and carp ( 6 ). Fish foodborne enteritis also is due to the dysregulation of oral tolerance, which is related to immunoregulation locally at the intestinal mucosa ( 7 ).…”

Effects of Low- and High-Level Gossypol and Sodium Butyrate Supplementation Under High-Level Gossypol Condition on Growth Performance and Intestinal Health of Hybrid Grouper (Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂)

“…At the end of the feeding experiment, all fish were starved for 24 h. First, the fish in each tank were counted and weighed, and the data obtained were used to calculate the WG, SGR, and survival (SR) and combined with the weight of feed consumed to calculate the feed coefficient ratio (FCR) (Yin et al, 2021a). For the intestine, part of the intestine near the cloacal pore, accounting for one-third of the total intestine of two randomly selected fish from each replicate, was stored in 4% formalin solution and used as paraffin-embedded TUNELstained sections; the distal intestine from four randomly selected fish from each replicate was stored at −80 • C and used for damage indicator determination, and the distal intestine from two randomly selected fish from each replicate was stored at −80 • C and used as PCR samples.…”