An Integrated Bile Acids Profile Determination by UHPLC-MS/MS to Identify the Effect of Bile Acids Supplement in High Plant Protein Diet on Common Carp (Cyprinus carpio)

Long-term effects of Nε-carboxymethyllysine intake on intestinal barrier permeability: Associations with gut microbiota and bile acids

Advanced glycation end products (AGEs) in processed foods are closely linked to intestinal injury. However, the long-term effects of exposure to free Nɛ-carboxymethyl lysine (CML), a prevalent AGE molecule, on intestinal barrier integrity have been rarely evaluated. This study investigated the temporal effects of CML exposure on intestinal barrier permeability in C57BL/6N mice at diet-related doses over 12, 14, and 16 weeks. No significant changes were observed at 12 weeks, but CML exposure significantly increased intestinal permeability at 14 and 16 weeks, accompanied by elevated serum LPS levels, colonic histological damage, and reduced tight junction protein expression at 16 weeks. CML exposure also altered gut microbiota composition and intestinal bile acid (BA) profiles, specifically reducing TDCA, GDCA, and GCDCA levels. Given the important role of colonic BA receptor signaling in maintaining the intestinal barrier integrity, the impact of CML on BA receptor signaling was assessed. CML exposure significantly downregulated BA receptor TGR5-YAP signaling in mice, while no significant effects were observed in vitro, suggesting that the changes observed in TGR5-YAP signaling in vivo may not result from the direct effects of CML. Spearman's correlation analysis revealed strong associations between altered gut microbiota, BA levels, TGR5-YAP signaling, and intestinal barrier injury. This study highlighted the chronic health risks of long-term CML intake and provided new insights into the links between CML-induced intestinal toxicity, gut microbiota, BA profiles, and BA receptor signaling.

Dietary cholesterol intervention could alleviate the intestinal injury of Oreochromis niloticus induced by plant-based diet via the intestinal barriers

This study aims to explore the effects of supplementing cholesterol in plant-based feed on intestinal barriers (including physical barrier, chemical barrier, immune barrier, biological barrier) of GIFT strain tilapia (Oreochromis niloticus). Four isonitrogenous and isolipidic diets were prepared as follows: plant-based protein diet (Con group) containing corn protein powder, soybean meal, cottonseed meal, and rapeseed meal, with the addition of cholesterol at a level of 0.6 % (C0.6 % group), 1.2 % (C1.2 % group), and 1.8 % (C1.8 % group), respectively. A total of 360 fish (mean initial weight of (6.08 ± 0.12) g) were divided into 12 tanks with 30 fish per tank, each treatment was set with three tanks and the feeding period lasted 9 weeks. Histological analysis revealed that both the C0.6 % and C1.2 % groups exhibited a more organized intestinal structure, with significantly increased muscle layer thickness compared to the Con group (P < 0.05). Furthermore, in the C1.2 % group, there was a significant up-regulation of tight junction-related genes (claudin-14, occludin, zo-1) compared to the Con group (P < 0.05). 5-ethynyl-2'-deoxyuridine staining results also demonstrated a notable enhancement in intestinal cell proliferation within the C1.2 % group (P < 0.05). Regarding the intestinal chemical barrier, trypsin and lipase activities were significantly elevated in the C1.2 % group (P < 0.05), while hepcidin gene expression was considerably down-regulated in this group but up-regulated in the C1.8 % group (P < 0.05). In terms of the intestinal immune barrier, inflammation-related gene expression levels (tnf-α, il-1β, caspase 9, ire1, perk, atf6) were markedly reduced in the C1.2 % group (P < 0.05). Regarding the intestinal biological barrier, the composition of the intestinal microbiota indicated that compared to the Con group, both the 0.6 % and 1.2 % groups showed a significant increase in Shannon index (P < 0.05). Additionally, there was a significant increase in the abundance of Firmicutes and Clostridium in the C1.2 % group (P < 0.05). In summary, supplementation of 1.2 % cholesterol in the plant-based diet exhibits the potential to enhance intestinal tight junction function and improve the composition of intestinal microbiota, thereby significantly promoting tilapia's intestinal health.

Gut microbiota-bile acid crosstalk and metabolic fatty liver in spotted seabass (Lateolabrax maculatus): The role of a cholesterol, taurine and glycine supplement

The prevalent practice of substituting fishmeal with plant protein frequently leads to disturbances in bile acid metabolism, subsequently increasing the incidence of metabolic liver diseases. Bile acid nutrients such as cholesterol, taurine and glycine have been shown to enhance bile acid synthesis and confer beneficial effects on growth. Therefore, this study aimed to investigate the effects of cholesterol-taurine-glycine (Ch-Tau-Gly) supplement on bile acid metabolism and liver health in spotted seabass (Lateolabrax maculatus) fed a plant-based diet. Two isonitrogenous and isolipidic diets were formulated: (1) plant protein-based diet (PP); (2) PP supplemented 0.5% cholesterol, 0.5% taurine and 1.3% glycine (CTG). Each experimental diet was randomly fed to quadruplicate groups of 30 feed-trained spotted seabass in each tank. The results revealed that supplementing plant-based diet with Ch-Tau-Gly supplement led to an increase in carcass ratio (meat yield) in spotted seabass (P < 0.05), indirectly contributing positively to their growth. The dietary supplement effectively suppressed endogenous cholesterol synthesis in the liver, promoted the expression of bile acid synthesis enzyme synthesis, and simultaneously the expression of intestinal fxr and its downstream genes, including hnf4α and shp (P < 0.05). The reduction in Lactobacillus_salivarius and bile salt hydrolase (BSH) were observed in CTG group with concurrently increased conjugated chenodeoxycholic acid (CDCA) bile acids (P < 0.05), suggesting the enhancement of the hydrophilicity of the bile acid pool. In CTG group, fatty liver was alleviated with a corresponding increase in lipid metabolism, characterized by a downregulation of genes associated with lipogenesis and lipid droplet deposition, along with an upregulation of genes related to lipolysis. Our study underscored the ability of Ch-Tau-Gly supplement to influence the gut microbiota, leading to an increase in the levels of conjugated CDCA (P < 0.05) in the bile acid pool of spotted seabass. The interplay between the gut microbiota and bile acids might constitute a crucial pathway in the promotion of liver health. These findings offer a promising solution, suggesting that Ch-Tau-Gly supplement have the potential to promote the growth of aquatic species and livestock fed on plant-based diets while addressing issues related to metabolic fatty liver.

Enhancing growth, liver health, and bile acid metabolism of tilapia (Oreochromis niloticus) through combined cholesterol and bile acid supplementation in plant-based diets

The present study aimed to compare the nutritional effects of cholesterol, bile acids, and combination of cholesterol with bile acids in plant-based diets on juvenile genetically improved farmed tilapia (GIFT; Oreochromis niloticus). The isonitrogenous (321 g/kg crude protein) and isolipidic (76 g/kg crude fat) diets (Con diet) were based on plant protein sources, which included corn gluten meal, soybean meal, cottonseed meal and rapeseed meal. The Con diet was supplemented with 12 g/kg cholesterol (CHO diet), 0.2 g/kg bile acids (BAs diet), a combination of 12 g/kg cholesterol and 0.2 g/kg bile acids (CHO-BAs diet), respectively. Each diet was fed to three tanks in an indoor recirculating aquaculture system for 9 weeks. Results showed that compared to the Con group, fish had a higher weight gain rate, hepatosomatic index, and a lower feed conversion ratio in the CHO-BAs group. The highest levels of whole-fish fat and ash were found in the Con group. Serum parameters, including activities of alanine aminotransferase (ALT) and aspartate transaminase (AST), along with levels of glucose (GLU) and triglyceride (TG) except for total cholesterol (TCHO), were lower in the CHO, BAs, and CHO-BAs groups than those in the Con group (P < 0.001). Histological examination revealed that fish in the Con group exhibited severe hepatocyte vacuolization and diminished hepatocyte proliferation. Gene expression analysis indicated that the transcriptional levels of bile acid metabolism-related genes (including fxr, fgf19, bsep) were up-regulated in the CHO-BAs group (P < 0.05), whereas cholesterol metabolism-related genes (acly and hmgcr) were down-regulated in both CHO and CHO-BAs groups (P < 0.001). Moreover, UPLC-MS/MS analysis revealed that the higher taurine-conjugated bile acids (T-BAs), followed by free bile acids (Free-BAs) and glycine (G-BAs) were determined in tilapia bile. Among these, taurochenodeoxycholic bile acid was the predominant bile acid. Dietary bile acids supplementation also increased the proportion of T-BAs (tauro β-muricholic acid and taurodehydrocholic acid) while decreasing Free-BAs in the fish bile. In conclusion, the incorporation of cholesterol with bile acids into plant-based diets can effectively reduce cholesterol uptake, suppress bile acids synthesis, enhance bile acids efflux, and promote hepatocyte proliferation, which is helpful for maintaining the normal liver morphology in tilapia, and thus improving its growth performance.

Effects of paraprobiotics on bile acid metabolism and liver health in largemouth bass (Micropterus salmoides) fed a cottonseed protein concentrate-based diet

Cottonseed protein concentrate is a sustainable fishmeal alternative in aquafeed. A 10-week experiment was conducted to investigate the effects of a cottonseed protein concentrate-based diet with and without multi-strain yeast fractions (MsYF) on growth, bile acid metabolism, and health in largemouth bass. Four hundred fish (54.0 ± 0.0 g) were casually distributed into 16 tanks (4 replicates/diet). Fish were fed with 4 iso-nitrogen and iso-energetic diets 3 times daily, including a fishmeal diet (FM), a soy protein concentrate-based diet (SPC; replacing 81% fishmeal protein), a cottonseed protein concentrate-based diet (CPC; replacing 81% fishmeal protein), and a CPC diet supplemented with 800 mg/kg MsYF (CPCY). Results showed that the survival of SPC was the lowest, i.e., 48%, with no apparent diet effect among other treatments; we omitted the SPC in additional analyses. Fish fed cottonseed protein concentrate-based diets showed lower growth than FM (P < 0.05). Fish fed CPC showed the highest nuclear dense hepatic phenotypes ratio (50%), followed by CPCY (33%) and FM (17%). Further, dietary CPC increased hepatic total cholesterol and triglyceride levels with concurrently increased cholesterol synthesis but decreased triglyceride synthesis-associated transcription levels (P < 0.05). Furthermore, dietary CPC increased bile acid synthesis but decreased bile acid transport-associated transcription levels (P < 0.05), and then induced an increment of plasma cholic acid and hepatic chenodeoxycholic acid content and the decrement of genus Romboustia (P < 0.05). Regarding the effect of MsYF, fish fed CPCY reduced hepatic lipid accumulation and total plasma bile acid content (P < 0.05) compared to CPC, suggesting an improvement in liver health. Also, dietary MsYF could reverse the microbiota community structure showing a similar gut microbial composition to FM. In conclusion, 81% of fishmeal protein replaced by cottonseed protein concentrate suppressed growth and liver health, while dietary MsYF might mitigate the negative impact of a high cottonseed protein concentrate level diet on liver functions via gut microbiota regulation.

Clostridium autoethanogenum protein inclusion in the diet for broiler: Enhancement of growth performance, lipid metabolism, and gut microbiota

This study aimed to investigate the effects of dietary supplementation of the new single-cell protein Clostridium autoethanogenum protein (CAP) on growth performance, plasma biochemical indexes, liver histology, lipid metabolism, and gut microbiota in Cobb broilers. According to the randomized block experimental design, 960 Cobb broilers (1d old) were divided into six treatments with eight replicates of 20 birds each. Six isonitrogenous and isoenergetic diets were formulated with different contents of CAP (0, 1, 2, 3, 4, and 5%) to replace soybean meal (SBM). The results showed that the addition of CAP did not influence liver health when it exceeded 2%. The protein metabolism markers and feed conversion rate increased (P < 0.05), significantly improving the growth performance. When the content of CAP was greater than 4%, it could promote lipolysis without affecting lipogenesis, decreasing the abdominal fat rate. There was no significant difference in MDA between these groups (P = 0.948). The increase of SOD and GSH-Px indicated the enhancement of antioxidant response. Alpha diversity did not significantly differ between groups (P > 0.05). Inclusion of 4% or less CAP led to the increase in beneficial microbiota, the concentration of short-chain fatty acids (SCFAs) such as acetic acid, propionic acid, and butyric acid (P < 0.05), and the concentration of primary bile acids such as cholic acid and goose deoxycholic acid (P < 0.05). While the concentration of secondary bile acids such as taurocholic acid and taurine goose deoxycholic acid was decreased (P < 0.05). These results illustrated that the CAP had a high potential for application in poultry nutrition. In terms of improving growth performance and antioxidant capacity and reducing fat deposition rate, 4% CAP content is recommended.