The objective of this study was to investigate the diet-induced metabolic changes that affect the brain tissue of juvenile pigs with NAFLD. This study explored the liver- brain axis and metabolic markers in the frontal cortex (FC) affected by liver damage. 18 male (M) and 20 female (F) Iberian pigs were randomly allocated to 1 of 3 high-fructose high-fat liquid diets (lard, olive oil, and coconut oil) and fed for 10 consecutive weeks. “Healthy” Iberian pigs were fed a eucaloric diet to establish a physiological baseline. Protein precipitation extraction using ultra-performance liquid chromatography-tandem quadrupole mass spectrometry was performed for primary metabolic and bile acid assays on FC samples. Univariate data were analyzed by one-way ANOVA, which included diet as the fixed effect and both replicate and pen nested in the diet as random effects. A more pronounced separation was observed in the PLS-DA between the COC and LAR/OLI diets. LC, C14:0 SM, and kynurenine, all metabolites linked to brain health, showed elevated levels in COC-fed pigs and reduced levels in animals fed OLI. Each of the three diets demonstrated heightened ratios of secondary bile acids to primary bile acids, with OLI-fed pigs showing increased TDCA:CA and TLCA:CA ratios associated with neurodegeneration (MahmoudianDehkordi et al., 2019). In conclusion, results may suggest that LAR could represent a more favorable dietary intervention for promoting brain health in pediatric NAFLD but further research is required.

Non-alcoholic fatty liver disease (NAFLD) represents the major cause of pediatric chronic liver pathology in the United States. The objective of this study was to investigate the effect of partial substitution of dietary lard by an isocaloric amount of olive or coconut oil on endpoints of NAFLD. Thirty-eight 15-d-old Iberian pigs housed in pens balanced for weight and sex were randomly assigned to receive 1 of 3 hypercaloric high-fructose high-fat (HFF) diets for 10 weeks: 1) lard (LAR; n=5 pens), 2) lard + olive oil (OLI, n=10), and 3) lard + coconut oil (COC; n=10). Additional pigs (BSL, n=4) were fed a eucaloric diet to establish baseline values. Animals were euthanized at 85 d of age after blood sampling. Liver tissue was collected for histology, metabolomics, and transcriptomics. Compared with BSL, OLI decreased high-density lipoproteins, phosphatidylcholines (PC), and total cholesterol in blood, and increased acylcarnitines in liver, whereas COC increased triacylglycerides (TAGs) in liver and blood. All HFF diets increased bile acids in liver, and decreased choline and fibroblast growth factor 19 in liver and blood. OLI and COC increased hepatic steatosis, necrosis, ballooning, and composite lesion score compared with LAR. OLI decreased gene expression of carnitine O-palmitoyltransferase 1, and COC increased expression of fatty acid binding proteins and acyl-CoA synthetase. In conclusion, partial replacement of dietary lard with olive and coconut oil dysregulated acylcarnitine metabolism and lipogenesis in the liver, increasing the severity of NAFLD in juvenile pigs.

The prevalence of non-alcoholic fatty liver disease (NAFLD) in children has increased over the past decades, creating a need for animal models that recapitulate the features of the pediatric disease. Iberian pigs have a leptin-resistant phenotype characterized by hyperleptinemia, hyperphagia, and extreme adipogenesis. We hypothesized that neonatal Iberian pigs fed a high fat high-fructose (HFF) diet will develop a pattern of liver injury resembling pediatric NAFLD. In addition, we sought to determine if a mixture of probiotics would prevent the disease. Animals were fed 1 of 4 diets containing (g/kg body weight × d) 0 g fructose, 11 g fat and 199 kcal (CON-N; n=8), 22 g fructose, 16 g fat and 300 kcal (HFF2-N; n=8), CON + probiotic (CON-P; n=6), or HFF2 + probiotic (HFF2-P; n=6) every 6 h for 70 d. The probiotic mixture (6.2 × 104 cfu/mL) contained Pediococcus acidilactici, Pediococcus pentosaceus, Lactobacillus plantarum and Bacillus amyloliquefaciens. Body weight was recorded every 3 d. Serum markers of liver injury and dyslipidemia were measured on d 40 and 65 at 2 h post feeding. Fasting leptin, insulin, glucose and homeostatic model assessment (HOMA) values were assessed on d 70. Liver and skeletal muscle (longissimus dorsi) were collected on d 70 for histology, triacylglyceride (TAG) quantification, relative gene expression, and Western blot analysis. Metabolomic analysis was performed on liver tissue and plasma. Body weight was not significantly greater in HFF fed pigs compared to CON. Leptin, alanine and aspartate aminotransferases, alkaline phosphatase, lactate dehydrogenase and total bilirubin were increased (P ≤ 0.001), and high and low density lipoproteins decreased (P ≤ 0.05) in HFF2-N and HFF2-P. Livers in HFF2-P and HFF2-N had higher relative weight and TAG (P ≤ 0.001), micro and macrovesicular steatosis, ballooning degeneration, Mallory-denk bodies, inflammation and necrosis, increased gene expression of TNFα, TGFβ, IL1α and PPARγ (P ≤ 0.001), and decreased ChREBP (P ≤ 0.001). A probiotic affect was seen as pigs fed CON-P and HFF2-P had higher insulin and HOMA values were increased (P ≤ 0.05). Western blot analysis showed dysregulation of autophagy in liver of pigs fed CON-P and HFF2-P, and in skeletal muscle of pigs fed CON-N and HFF2-N. Metabolomic analysis demonstrated dysregulation of one-carbon metabolism, the tricarboxylic acid cycle (TCA), the urea cycle, and amino acid metabolism of pigs fed HFF2 diets compared to CON diets. In conclusion, Iberian pigs fed a HFF diet recapitulate many pediatric NAFLD-associated features, in the absence of obesity and independently of probiotic supplementation, suggesting a potentially suitable model for pediatric NAFLD research. Furthermore, probiotic supplementation did not ameliorate the onset of NAFLD when fed in conjunction with a HFF diet.