Metabolic Effects of Dietary Glycerol Supplementation in Muscle and Liver of European Seabass and Rainbow Trout by 1H NMR Metabolomics

Association between dietary total choline and abdominal aorta calcification among older US adults: A cross-sectional study of the National Health and Nutrition Examination Survey

BACKGROUND

Numerous studies indicate a potential bidirectional association between dietary choline intake and its derivative, betaine, and subclinical atherosclerosis. However, little research has been conducted on the relationship between dietary choline and severe abdominal aortic calcification (SAAC).

METHODS

This cross-sectional study analyzed population-based data from the National Health and Nutrition Examination Survey (2013-2014). Choline intake and food sources were measured using two 24-h dietary-recall interviews. The abdominal aortic calcification score was measured using a dual-emission x-ray absorptiometry scan. To assess the relationship between choline intake and SAAC, the study utilized restricted cubic spline and a multivariable logistic regression model.

RESULTS

Among the 2640 individuals included in the study, 10.9% had SAAC. After adjusting for all selected covariates, compared with the lowest quartile of dietary choline, the odds ratios of SAAC for the second-quartile, third-quartile, and fourth-quartile dietary choline intake were 0.63 (95% confidence interval [CI], 0.43-0.93), 0.63 (95% CI, 0.42-0.94), and 0.77 (95% CI, 0.5-1.16), respectively. The study found an L-shaped relationship between dietary choline and SAAC in the dose-response analysis. Subgroup analyses did not demonstrate any statistically significant interaction effects for any subgroup.

CONCLUSION

The study found that a higher intake of dietary choline is associated with a lower prevalence of SAAC. The dose-response analysis revealed an L-shaped relationship between dietary choline and SAAC. However, further studies are warranted to investigate the direct role of choline in the development of SAAC.

Prediction of Feed Efficiency and Performance-Based Traits in Fish via Integration of Multiple Omics and Clinical Covariates

Fish aquaculture is a rapidly expanding global industry, set to support growing demands for sources of marine protein. Enhancing feed efficiency (FE) in farmed fish is required to reduce production costs and improve sector sustainability. Recognising that organisms are complex systems whose emerging phenotypes are the product of multiple interacting molecular processes, systems-based approaches are expected to deliver new biological insights into FE and growth performance. Here, we establish 14 diverse layers of multi-omics and clinical covariates to assess their capacities to predict FE and associated performance traits in a fish model (Oncorhynchus tshawytscha) and uncover the influential variables. Inter-omic relatedness between the different layers revealed several significant concordances, particularly between datasets originating from similar material/tissue and between blood indicators and some of the proteomic (liver), metabolomic (liver), and microbiomic layers. Single- and multi-layer random forest (RF) regression models showed that integration of all data layers provide greater FE prediction power than any single-layer model alone. Although FE was among the most challenging of the traits we attempted to predict, the mean accuracy of 40 different FE models in terms of root-mean square errors normalized to percentage was 30.4%, supporting RF as a feature selection tool and approach for complex trait prediction. Major contributions to the integrated FE models were derived from layers of proteomic and metabolomic data, with substantial influence also provided by the lipid composition layer. A correlation matrix of the top 27 variables in the models highlighted FE trait-associations with faecal bacteria (Serratia spp.), palmitic and nervonic acid moieties in whole body lipids, levels of free glycerol in muscle, and N-acetylglutamic acid content in liver. In summary, we identified subsets of molecular characteristics for the assessment of commercially relevant performance-based metrics in farmed Chinook salmon.

Carbohydrate tolerance in Amazon tambaqui (Colossoma macropomum) revealed by NMR-metabolomics - Are glucose and fructose different sugars for fruit-eating fish?

In the present study, two approaches were followed to evaluate the metabolic responses of tambaqui (Colossoma macropomum), a frugivorous species, to intraperitoneal (IP) administration of glucose (GLU) and fructose (FRU) in fed (FED) and 10-day fasted (FAST) fish. Glucose and fructose tolerance tests were performed to assess the carbohydrate utilization and complementary NMR-metabolomics analyses were done to elucidate the impacts of sugar mobilization on the metabolic profile of plasma, liver and muscle. Blood was sampled from FED groups at 0, 3, 6 and 24 h; and at 0 and 24 h from FAST groups. Significant differences were observed in the hyperglycaemic peak between sugars at 3 h (GLU - 13.7 ± 2.0 mM vs. FRU - 8.7 ± 1.1 mM; saline 6.3 ± 0.6 mM) and on the return to normoglycaemia (GLU - 8.5 ± 2.2 mM vs. FRU - 5.2 ± 0.9 mM; saline 4.9 ± 0.6 mM) 6 h after IP on the FRU fish. The NMR-metabolomics approach allowed to conclude that tambaqui seems to be more responsive to the feeding regime (FED vs. FAST) than to the injected sugar (FRU vs. GLU). From the studied tissues, plasma showed no significant variations between feeding regimes at 24 h after IP, while muscle and liver revealed some variations on the final metabolome profile between FED and FAST groups. The metabolome variations between feeding regimes are indicative of changes on the amino acid utilization. Fish from FAST group seem to utilize amino acids as energy source rather than for protein synthesis and muscle growth. Variations on glucose concentration in muscle can also indicate different utilization of the sugars depending on the feeding regime.

Digesta and Plasma Metabolomics of Rainbow Trout Strains with Varied Tolerance of Plant-Based Diets Highlights Potential for Non-Lethal Assessments of Enteritis Development

The replacement of fishmeal in aquafeeds is essential to the sustainability of aquaculture. Besides the procurement of alternative protein sources, fish can also be selected for better performance on plant-based alternative diets. Rainbow trout (Oncorhynchus mykiss) is one such species in which the strain ARS-Sel has been selected for higher growth and enhanced utilization when fed soy-based diets. The aim of this study was to compare fish growth and plasma and digesta metabolomes between ARS-Sel and two commercial strains (CS-1 and CS-2), when fed plant-protein (PM) and fishmeal-based (FM) diets, and to correlate them with the onset of enteritis. An NMR-metabolomics approach was taken to assess plasma and digesta metabolite profiles. Diet and strain showed significant effects on fish growth, with the ARS-Sel fish receiving the PM diet reaching the highest final weight at sampling. Multivariate analysis revealed differences between plasma and digesta metabolite profiles of ARS-Sel and CS (CS-1 considered together with CS-2) PM-fed groups in the early stages of enteritis development, which was confirmed by intestinal histology. As reported in previous studies, the ARS-Sel strain performed better than the commercial strains when fed the PM diet. Our findings also suggest that metabolomic profiles of plasma and digesta, samples of which can be obtained through non-lethal methods, offer valuable insight in monitoring the occurrence of enteritis in carnivorous aquaculture species due to plant-based diets.

Integrated metabolomic and gene expression analyses to study the effects of glycerol monolaurate on flesh quality in large yellow croaker (Larimichthys crocea)

To improve the quality of cultured large yellow croaker (Larimichthys crocea), this study was performed to study the impacts of glycerol monolaurate (GML) on the nutritional value, growth performance, muscle texture, and taste intensity of L. crocea. The results showed that GML as a feed additive significantly increased the crude lipid content and reduced the diameters of muscle fibers, which in turn markedly altered the flesh texture in terms of cohesiveness. Moreover, the taste indicators (umami and richness) and flavor-related amino acid (glutamic acid, glycine, and proline) contents of L. crocea muscle were significantly higher in the GML group. Metabolomic and gene expression analyses showed that GML supplementation could significantly improve amino acid biosynthesis and metabolism, promote protein and lipid synthesis, and activate myogenic-related signaling pathways of L. crocea. Consequently, adding an appropriate amount of GML to fish feed would be conducive to providing healthy, nutrient-rich and acceptably flavored aquatic-products.

Hepatic Glycerol Metabolism-Related Genes in Carnivorous Rainbow Trout (Oncorhynchus mykiss): Insights Into Molecular Characteristics, Ontogenesis, and Nutritional Regulation

Glycerol metabolism in rainbow trout is poorly studied even though it is at the interface between lipid and glucose metabolism. Moreover, glycerol can be an important ingredient in new aquafeed formulation to decrease the catabolism of dietary amino acids. Thus, the present study aimed to characterize for the first time the different genes coding for key enzymes and proteins involved in hepatic glycerol metabolism. From the trout genomes, all the paralogous genes coding for glycerol transport (aqp9b), glycerol kinase (gk2a and gk5), glycerol-3-phosphate phosphatase (pgp), and glycerol-3-phosphate dehydrogenase (gpd1a, gpd1b, and gpd1c) were identified. The ontogenesis determined that the capacity to metabolize glycerol begins with the apparition of the liver during the development (stage 22) and are more expressed at the endogenous–exogenous feeding period (stage 35). The postprandial regulation of the expression of these genes in juvenile trout showed that the postprandial peak of expression is between 4 and 24 h after the last meal for many of the genes, demonstrating that glycerol metabolism could be nutritionally regulated at a molecular level. However, surprisingly, no regulation of the mRNA abundance for the glycerol metabolism-related genes by different levels of dietary glycerol (0, 2.5, and 5%) have been detected, showing that hepatic glycerol metabolism is poorly regulated at a molecular level by dietary glycerol in rainbow trout juveniles.