Effect of Dietary Marula Nut Meal on Liver Lipid Content and Surrogate Markers of Liver and Kidney Function of Broiler and Layer Japanese Quail

Marula nut meal (MNM) can substitute soyabean meal (SBM) as a dietary protein source in Japanese quail diets without compromising growth performance and egg production. However, MNM has a high residual oil content which may impact metabolic health. The effects of MNM on hepatic lipid content and general, liver and kidney health have not been determined in both broilers and layers. Accordingly, two studies were run. In the broiler study two hundred 9-days old Japanese quail were randomly allocated to five diets wherein MNM replaced SBM on a crude protein (CP) basis at 0%, 25%, 50%, 75% and 100%, respectively, in both grower and finisher diets. In the layer study, sixty 5-weeks old Japanese maiden hens, individually housed, were randomly allocated to five-layer diets where MNM replaced SBM on a graded CP basis as for the broilers and fed for 8 weeks. At study termination the birds were slaughtered, blood collected and plasma harvested. Livers were excised, weighed and liver lipid content determined. Plasma surrogate markers of general health, liver and kidney function were determined. Dietary MNM had no effect (P > 0.05) on liver lipid content as well plasma surrogate markers of general health, liver and kidney function of the broiler quail. Dietary MNM at 75% of SBM CP significantly increased plasma phosphorus concentration of quail hens compared to that of counterparts fed control. Dietary MNM can be used in broiler and layer Japanese quail diets without risking development of fatty livers and compromising liver and kidney function.

Imbalanced Activation of Wnt-/β-Catenin-Signaling in Liver Endothelium Alters Normal Sinusoidal Differentiation

Endothelial wingless-related integration site (Wnt)-/β-catenin signaling is a key regulator of the tightly sealed blood–brain barrier. In the hepatic vascular niche angiokine-mediated Wnt signaling was recently identified as an important regulator of hepatocyte function, including the determination of final adult liver size, liver regeneration, and metabolic liver zonation. Within the hepatic vasculature, the liver sinusoidal endothelial cells (LSECs) are morphologically unique and functionally specialized microvascular endothelial cells (ECs). Pathological changes of LSECs are involved in chronic liver diseases, hepatocarcinogenesis, and liver metastasis. To comprehensively analyze the effects of endothelial Wnt-/β-catenin signaling in the liver, we used endothelial subtype-specific Clec4g-iCre mice to generate hepatic ECs with overexpression of Ctnnb1. In the resultant Clec4g-iCretg/wt;Ctnnb1(Ex3)fl/wt (Ctnnb1OE−EC) mice, activation of endothelial Wnt-/β-catenin signaling resulted in sinusoidal transdifferentiation with disturbed endothelial zonation, that is, loss of midzonal LSEC marker lymphatic vessel endothelial hyaluronic acid receptor 1 (Lyve1) and enrichment of continuous EC genes, such as cluster of differentiation (CD)34 and Apln. Notably, gene set enrichment analysis revealed overrepresentation of brain endothelial transcripts. Activation of endothelial Wnt-/β-catenin signaling did not induce liver fibrosis or alter metabolic liver zonation, but Ctnnb1OE−EC mice exhibited significantly increased plasma triglyceride concentrations, while liver lipid content was slightly reduced. Ctnnb1 overexpression in arterial ECs of the heart has been reported previously to cause cardiomyopathy. As Clec4g-iCre is active in a subset of cardiac ECs, it was not unexpected that Ctnnb1OE−EC mice showed reduced overall survival and cardiac dysfunction. Altogether, balanced endothelial Wnt-/β-catenin signaling in the liver is required for normal LSEC differentiation and for maintenance of normal plasma triglyceride levels.

Fetal programming by androgen excess impairs liver lipid content and PPARg expression in adult rats

It is known that prenatal hyperandrogenization induces alterations since early stages of life, contributing to the development of polycystic ovary syndrome affecting the reproductive axis and the metabolic status, thus promoting others associated disorders, such as dyslipidemia, insulin resistance, liver dysfunction, and even steatosis. In this study, we aimed to evaluate the effect of fetal programming by androgen excess on the hepatic lipid content and metabolic mediators at adult life. Pregnant rats were hyperandrogenized with daily subcutaneous injections of 1 mg of free testosterone from days 16 to 19 of pregnancy. The prenatally hyperandrogenized (PH) female offspring displayed two phenotypes: irregular ovulatory phenotype (PHiov) and anovulatory phenotype (PHanov), with different metabolic and endocrine features. We evaluated the liver lipid content and the main aspect of the balance between fatty acid (FA) synthesis and oxidation. We investigated the status of the peroxisomal proliferator-activated receptors (PPARs) alpha and gamma, which act as lipid mediators, and the adipokine chemerin, one marker of liver alterations. We found that prenatal hyperandrogenization altered the liver lipid profile with increased FAs levels in the PHanov phenotype and decreased cholesterol content in the PHiov phenotype. FA metabolism was also disturbed, including decreased mRNA and protein PPARgamma levels and impaired gene expression of the main enzymes involved in lipid metabolism. Moreover, we found low chemerin protein levels in both PH phenotypes. In conclusion, these data suggest that prenatal hyperandrogenization exerts a negative effect on the liver and alters lipid content and metabolic mediators’ expression at adult age.

Characterization of the Plasma Lipidome in Dairy Cattle Transitioning from Gestation to Lactation: Identifying Novel Biomarkers of Metabolic Impairment

The discovery of novel biomarkers for peripartal diseases in dairy cows can improve our understanding of normal and dysfunctional metabolism, and lead to nutritional interventions that improve health and milk production. Our objectives were to characterize the plasma lipidome and identify metabolites associated with common markers of metabolic disease in peripartal dairy cattle. Multiparous Holstein cows (n = 27) were enrolled 30 d prior to expected parturition. Blood and liver samples were routinely collected through to d 14 postpartum. Untargeted lipidomics was performed using quadrupole time-of-flight mass spectrometry. Based on postpartum measures, cows were categorized into low or high total fatty acid area under the curve (total FAAUC; d 1–14 postpartum; 4915 ± 1369 vs. 12,501 ± 2761 (μmol/L × 14 d); n = 18), β-hydroxybutyrate AUC (BHBAAUC; d 1–14 postpartum; 4583 ± 459 vs. 7901 ± 1206 (μmol/L × 14 d); n = 18), or liver lipid content (d 5 and 14 postpartum; 5 ± 1 vs. 12 ± 2% of wet weight; n = 18). Cows displayed decreases in plasma triacylglycerols and monoalkyl-diacylglycerols, and the majority of phospholipids reached a nadir at parturition. Phosphatidylcholines (PC) 32:3, 35:5, and 37:5 were specific for high total FAAUC, PC 31:3, 32:3, 35:5, and 37:5 were specific for high BHBAAUC, and PC 31:2, 31:3, and 32:3 were specific for high liver lipid content. PC 32:3 was specific for elevated total FA, BHBA, and liver lipid content. Lipidomics revealed a dynamic peripartal lipidome remodeling, and lipid markers associated with elevated total FA, BHBA, and liver lipid content. The effectiveness of nutrition to impact these lipid biomarkers for preventing excess lipolysis and fatty liver warrants evaluation.

Maternal provisioning gives young-of-the-year Hammerheads a head start in early life

For species that do not provide parental care after birth, excess maternal provisioning during development, beyond what is required for embryogenesis, provides offspring with resources to increase their chances of survival. Maternally derived resources are expected to be important for buffering offspring against limited food resources at birth or time needed to learn how to properly feed. Young-of-the-year (YOY) cryptic Scalloped Hammerheads (Sphyrna lewini) and Carolina Hammerheads (Sphyrna gilberti) were sampled from nurseries along the US Atlantic Coast and compared for a number of biological condition metrics across three developmental stages. Large declines in liver lipid content and hepatosomatic indices were found in neonatal sharks, using umbilical scar healing as a proxy for time since birth. Feeding commenced quickly as 96% of sharks had prey remnants in their stomachs. The combination of rapid exhaustion of maternally provided resources and high occurrence of stomachs with prey contents indicate that nursery quality, with respect to prey availability, may be important for YOY hammerhead survivorship. While externally the two species are morphologically similar, longer length-at-birth in S. lewini and higher hepatic condition in neonatal S. gilberti suggest that aspects of reproductive biology, including physiology, may differ between species. While more information is needed to distinguish life history differences between these two species, data collected from YOY may serve as a useful proxy to inform management when adult samples of cryptic species are difficult to collect.

Effects of Amino Acid Supplementation on Liver Lipid Content: A Randomized, Double-Blinded, Placebo-Controlled Trial

Objectives To test whether chronic ingestion of essential amino acids (EAAs) plus arginine lowers liver lipid content when compared with a placebo (non-essential amino acids; NEAAs). Methods Older adults (50–75 y) with elevated fasting plasma triacylglycerol (TAG) concentrations were recruited into the study. After screening (week -2), all participants ingested placebo (NEAAs; alanine, aspartic acid, and serine) capsules twice daily (between meals) for two weeks and 3 T nuclear magnetic resonance spectroscopy scans were used to determine baseline (week 0) liver lipid percentage. Participants were then randomised to receive capsules containing 11 g of EAAs plus arginine (n = 10) or NEAAs (n = 9) twice daily for eight weeks, using a double-blinded design. Follow-up NMR spectroscopy scans were conducted at eight weeks after the onset of randomised supplementation (week 8) to determine the impact on liver lipids. Results Liver lipid percentage (mean ± standard deviation) was not significantly altered by randomised supplementation in either the EAAs plus arginine group (Pre: 9.08 ± 7.90%; Post: 8.94 ± 6.91%; P = 0.65) or the NEAAs group (Pre: 10.23 ± 7.20%; Post: 9.65 ± 7.70%; P = 0.18). Change in fasting plasma TAG during placebo run-in (Week 0 minus screening) was significantly negatively correlated with change in liver lipid content (week 8 minus week 0) for the EAAs plus arginine group (r = −0.722; P = 0.02), but not for the NEAAs group A (r = −0.479; P = 0.19). Conclusions Eight weeks of essential amino acids plus arginine ingestion did not significantly lower liver lipid content in older adults. However, ingestion of non-essential amino acids during the run-in period may have influenced the effect on liver fat of subsequent randomised amino acid supplementation, suggesting further investigation is warranted. Funding Sources The study was sponsored by NIH/NIA (award to EB), and the Roy and Christine Sturgis Charitable Trust (award to NMH). Screenings and study visits were undertaken within the ITS-Clinical Research Center at UTMB, funded by NIH/NCRR, and within the UAMS Donald W. Reynolds Institute on Aging at UAMS, funded by NIH/NIA. NMH and EB were also funded by the Arkansas Biosciences Institute, the major research component of the Arkansas Tobacco Settlement Proceeds Act of 2000.

Hepatic IKKε expression is dispensable for high-fat feeding-induced increases in liver lipid content and alterations in glucose tolerance

There are endocrine and immunological changes that occur during onset and progression of the overweight and obese states. The inhibitor of nuclear factor-κB kinase-ε (IKKε) was originally described as an inducible protein kinase; whole body gene deletion or systemic pharmaceutical targeting of this kinase improved insulin sensitivity and glucose tolerance in mice. To investigate the primary sites of action associated with IKKε during weight gain, we describe the first mouse line with conditional elimination of IKKε in the liver (IKKεAlb–/–). IKKεAlb–/– mice and littermate controls gain weight, show similar changes in body composition, and do not display any improvements in insulin sensitivity or whole body glucose tolerance. These studies were conducted using breeder chow diets and matched low- vs. high-fat diets. While glycogen accumulation in the liver is reduced in IKKεAlb–/– mice, lipid storage in liver is similar in IKKεAlb–/– mice and littermate controls. Our results using IKKεAlb–/– mice suggest that the primary action of this kinase to impact insulin sensitivity during weight gain lies predominantly within extrahepatic tissues.

Variations in hepatic lipid species of age-matched male mice fed a methionine-choline-deficient diet and housed in different animal facilities

Background Non-alcoholic steatohepatitis (NASH) is a common disease and feeding mice a methionine-choline-deficient (MCD) diet is a frequently used model to study its pathophysiology. Genetic and environmental factors influence NASH development and liver lipid content, which was studied herein using C57BL/6 J mice bred in two different animal facilities. Methods Age-matched male C57BL/6 J mice bred in two different animal facilities (later on referred to as WT1 and WT2) at the University Hospital of Regensburg were fed identical MCD or control chows for 2 weeks. Hepatic gene and protein expression and lipid composition were determined. Results NASH was associated with increased hepatic triglycerides, which were actually higher in WT1 than WT2 liver in both dietary groups. Cholesterol contributes to hepatic injury but was only elevated in WT2 NASH liver. Ceramides account for insulin resistance and cell death, and ceramide species d18:1/16:0 and d18:1/18:0 were higher in the NASH liver of both groups. Saturated sphingomyelins only declined in WT1 NASH liver. Lysophosphatidylcholine concentrations were quite normal in NASH and only one of the 12 altered phosphatidylcholine species declined in NASH liver of both groups. Very few phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol species were comparably regulated in NASH liver of both animal groups. Seven of these lipid species declined and two increased in NASH. Notably, hepatic mRNA expression of proinflammatory (F4/80, CD68, IL-6, TNF and chemerin) and profibrotic genes (TGF beta and alpha SMA) was comparable in WT1 and WT2 mice. Conclusions Mice housed and bred in different animal facilities had comparable disease severity of NASH whereas liver lipids varied among the groups. Thus, there was no specific lipid signature for NASH in the MCD model.