HC Diet Research Articles

Astaxanthin attenuates glucose-induced liver injury in largemouth bass: role of p38MAPK and PI3K/Akt signaling pathways

BackgroundAstaxanthin (ASX) has been documented to exert beneficial influence on various processes in fish. Largemouth bass (Micropterus salmoides) serves as a common model for studying glucose-induced liver disease, making it imperative to investigate the regulatory mechanisms underlying its liver health.MethodsLargemouth bass were fed with a control diet (CON), a high carbohydrate diet (HC), or a HC diet supplemented astaxanthin (HCA) for 8-weeks, followed by the glucose tolerance test (GTT). Primary hepatocytes were treated with low glucose and high glucose combined with different concentrations of astaxanthin for 48 h. The histopathology, enzymology, transcriptomics, molecular biology and cell biology were combined to investigate the mechanism of liver injury.ResultsThis study provides evidence for the protective effects of ASX against growth performance reduction and hepatic liver injure in largemouth bass fed HC diet. In GTT, HCA diet exhibited an improvement in glucose tolerance following glucose loading. Although HCA diet did not restore the expression of insulin resistance-related genes in livers at different time during the GTT, the addition of ASX in the long-term HC diet did improve the insulin resistance pathway by regulating the PTP1B/PI3K/Akt signaling pathway. Hepatic transcriptome analyses showed that ASX plays an essential role in the modulation of glucose homeostasis in response to treated with HC diet. In in vitro study, ASX treatment resulted in an exaltation in cell viability and a reduction in the rate of cell apoptosis and reactive oxygen species (ROS). Additionally, astaxanthin was observed to improve apoptosis induced by high-glucose via p38MAPK/bcl-2/caspase-3 signaling pathway.ConclusionsAstaxanthin exhibited a protective effect against apoptosis by regulating p38MAPK/bcl-2/caspase-3 pathway, and ameliorated insulin resistance by activating the PTP1B/PI3K/Akt pathway. This study elucidated the mechanism of astaxanthin in the liver injury of largemouth bass from a new perspective and provided a new target for the treatment of insulin resistance.Graphical

Glibenclamide alters the brain protein profile and morphometry of hippocampal regions in mice fed with a high-refined carbohydrate diet

A high-refined carbohydrate diet (HC diet) has shown impacts not only on metabolic disorders, but also on cognitive and behavioral functions. However, its effects at the protein and morphological level in the brain are not known. In order to investigate the differential expression of proteins in the brain of Balb/c mice fed with a HC diet and treated or not with glibenclamide, biochemical and histological assays were performed. The brains of animals fed for eight weeks with a standard rodent diet or HC diet, and treated or not with glibenclamide for four weeks were homogenized and the supernatant was subjected to 12.5% ​​SDS-PAGE. The brains were also blocked and 3 μm sections were stained with Hematoxylin-Eosin and analyzed using light microscopy. The electrophoretic profile of samples from untreated animals revealed protein expression without significant differences, while the group treated with glibenclamide revealed protein bands with differential expression (44.8, 42.2 and 39.8 KDa). The proteins were predicted using a bioinformatic tool and it is suggested that, for the most part, they are related to the energy metabolism of the brain. Histological analysis of the hippocampus demonstrated similarities between animals fed with a standard diet and HC diet, but with differences in the number of neurons in the CA2 and CA3 regions, and a tendency to cell death in the dentate gyrus of animals group HC diet. These results revealed one of the regions of the brain affected by excess carbohydrates, as well as candidate proteins for proteomic analysis to further investigate the effects of dietary sugars on molecular mechanisms and neurogenesis in the hippocampus.

Influence of maternal α-lipoic acid supplementation in Sprague Dawley rats on maternal and fetal metabolic health in pregnancies complicated by obesity

The objective of this study was to investigate the influence of α-lipoic acid (LA; R enantiomer) supplementation on maternal and fetal metabolic health in pregnancies complicated by maternal obesity. Forty female Sprague-Dawley rats were randomized to one of 4 treatment groups (n=10/group) throughout prepregnancy (3 weeks) and gestation (20 days): (1) a low calorie control (CON); (2) a high calorie obesity-inducing diet (HC); (3) the HC diet with 0.25% LA (HC+LA) or; (4) the HC diet pair-fed to match the caloric intake of the HC+LA group (HC+PF). On gestation day 20, pregnant rats were placed under anesthesia for collection of maternal/fetal blood and tissues. Compared with the HC group, LA-supplemented mothers demonstrated lower maternal prepregnancy and gestational weight gain (GWG), improved glycemic control (lower homeostatic model assessment for insulin resistance), and higher cholesterol concentrations in serum [high-density lipoprotein cholesterol (HDL-C) and low-and very-low density lipoprotein cholesterol (LDL/VLDL) fractions] and liver. Male and female fetuses from LA-supplemented mothers exhibited lower body weight, improved insulin sensitivity, and evidence of altered lipid metabolism including lower serum HDL-C, lower serum triglyceride (TG), and increased hepatic TG accumulation. Although maternal LA supplementation showed some benefit for both mothers and fetuses with respect to obesity and glycemic control, concern about the potential longer-term implications of liver cholesterol (mothers) and TG accumulation (fetuses) needs further investigation.

Postnatal Consumption of Black Bean Powder Protects against Obesity and Dyslipidemia in Male Adult Rat Offspring from Obese Pregnancies.

The adverse influence of maternal obesity on offspring metabolic health throughout the life-course is a significant public health challenge with few effective interventions. We examined if black bean powder (BBP) supplementation to a high-calorie maternal pregnancy diet or a postnatal offspring diet could offer protection against the metabolic programming of metabolic disease risk in adult offspring. Female Sprague Dawley rats were randomly assigned to one of three diets (n = 10/group) for a 3-week pre-pregnancy period and throughout gestation and lactation: (i) a low-caloric control diet (CON); (ii) a high-caloric obesity-inducing diet (HC); or (iii) the HC diet with 20% black bean powder (HC-BBP). At weaning [postnatal day (PND) 21], one male pup from each dam was weaned onto the CON diet throughout the postnatal period until adulthood (PND120). In addition, a second male from the HC group only was weaned onto the CON diet supplemented with BBP (CON-BBP). Thus, based on the maternal diet exposure and offspring postnatal diet, four experimental adult offspring groups were compared: CON/CON, HC/CON, HC-BPP/CON, and HC/CON-BBP. On PND120, blood was collected for biochemical analysis (e.g., lipids, glycemic control endpoints, etc.), and livers were excised for lipid analysis (triglycerides [TG] and cholesterol) and the mRNA/protein expression of lipid-regulatory targets. Compared with the CON/CON group, adult offspring from the HC/CON group exhibited a higher (p < 0.05) body weight (BW) (682.88 ± 10.67 vs. 628.02 ± 16.61 g) and hepatic TG (29.55 ± 1.31 vs. 22.86 ± 1.85 mmol/g). Although maternal BBP supplementation (HC-BBP/CON) had little influence on metabolic outcomes, the consumption of BBP in the postnatal period (HC/CON-BBP) lowered hepatic TG and cholesterol compared with the other treatment groups. Reduced hepatic TG in the HC/CON-BBP was likely associated with lower postnatal BW gain (vs. HC/CON), lower mRNA and protein expression of hepatic Fasn (vs. HC/CON), and lower serum leptin concentration (vs. CON/CON and HC groups). Our results suggest that the postnatal consumption of a black-bean-powder-supplemented diet may protect male rat offspring against the programming of obesity and dyslipidemia associated with maternal obesity. Future work should investigate the bioactive fraction of BBP responsible for the observed effect.

48 The ruminal microbiome of conventionally and artificially raised lambs fed high-concentrate and high-forage post-weaning diets

Abstract Artificially rearing lambs on milk replacer impacts development of the ruminal microbiome. The objective was to evaluate the extent to which pre-weaning management influences the ruminal microbiome of lambs during finishing. A finishing study was conducted using 32 Polypay conventionally-raised (CR; n = 10 rams, 6 ewes) or artificially raised (AR; n = 10 rams, 6 ewes) lambs weaned at 56 d of age. Following weaning, lambs were adapted to a HC (85:15 concentrate:forage) diet for 35 d. Lambs were then blocked by sex and body weight and randomly assigned to either continue receiving HC or abruptly transition to a HF (50:50 concentrate:forage) diet. Individually-housed lambs were fed ad libitum through a target slaughter weight (rams: 59.0; ewes: 54.4 kg). Rumen fluid samples were collected via oral intubation on d 0, 14, 28, and when lambs reached slaughter weight. Analysis of 16S rRNA gene sequences was conducted in QIIME 2 (v.2023.2). Taxonomy was assigned with SILVA (SSU 138). Diversity was analyzed by PERMANOVA. Random forest classification was applied to determine if pre-weaning management and diet could be predicted using microbial composition. Alpha diversity did not differ in CR vs. AR lambs at the initial sampling (P &amp;gt; 0.22), but species richness was greater in HR lambs regardless of pre-weaning management from d 14 through slaughter (P &amp;lt; 0.01). Beta diversity did differ between CR and AR at the initial sampling (P ≤ 0.02). The influence of pre-weaning management was still present in weighted UniFrac distances by d 14 (P = 0.09), but effects of pre-weaning management were no longer apparent from d 28 through slaughter (P ≥ 0.28). Similarly random forest modeling was able to predict pre-weaning management in initial samples (accuracy: 0.75 ± 0.15). Accuracies decreased over the study period (d 14: 0.58 ± 0.07; d 28: 0.50 ± 0.15; slaughter: 0.45 ± 0.07), whereas model performance improved for prediction of diet (d 14: 0.83 ± 0.15; d 28: 0.87 ± 0.12; slaughter: 0.97 ± 0.07). The most important feature in predicting pre-weaning management at initial sampling belonged to Ruminococcus, and 9 ASV assigned to Prevotella were among the most important features in the model. Five features were present in the top 20 most important features for both the initial and finishing models, and included ASV assigned to Streptococcus, Lactobacillus, and Bifidobacterium. These results illustrated continued impacts of early-life management on ruminal microbiome composition at the beginning of the finishing period, even though CR and AR lambs had been adapted to the same diet for more than 1 mo. While pre-weaning effects were muted over the course of finishing as diet became the predominant factor, the influence of early-life management was still detectable by the end of the finishing period.

Effects of High-Concentrate-Induced SARA on Antioxidant Capacity, Immune Levels and Rumen Microbiota and Function in Goats.

This study aims to explore the antioxidant, immune, and enzyme metabolism aspects in goats experiencing subacute ruminal acidosis (SARA). Furthermore, we seek to elucidate the relationship between the symbiotic microbiota of goats and their metabolic function. Sixteen goats were equally divided into two groups and fed a normal-concentrate diet (NC, 55% concentrate) or a high-concentrate diet (HC, 90% concentrate) for five weeks. We found that the HC diet reduced the total antioxidant capacity (T-AOC) (p = 0.022) and increased interleukin-1β (IL-1β) (p = 0.015), interleukin-4 (IL-4) (p = 0.008) and interleukin-6 (IL-6) (p = 0.002) concentration of goats. Simultaneously, the HC diet significantly increased the concentrations of alkaline phosphatase (ALP) and amylase (AMY) in the blood and rumen fluid of goats (p < 0.05). Microbial analysis in the rumen of goats revealed that the HC diet decreased bacterial richness and diversity, as evidenced by the changed observed species, Chao 1, PD whole tree and Shannon when compared to the NC diet (p < 0.01). The proportion of Proteobacteria increased while that of Spirochaetes and Fibrobacteres significantly decreased with the HC diet (p < 0.05). The Christensenellaceae_R-7_group and Ruminococcaceae_UCG-010 in rumen was notably decreased when a diet was switched from 55% concentrate diet to 90% concentrate diet (p < 0.05). Additionally, microbial functional potentials deduced that the HC diet significantly increased the abundance of the citrate cycle (TCA cycle) (ko00020) associated with carbohydrate metabolism (p = 0.028). Furthermore, the HC diet significantly increased the glutathione metabolism (ko00480) associated with the metabolism of other amino acids (p = 0.008). Our findings suggested that SARA reduced the total antioxidant capacity and increased levels of inflammatory factors in goats, as well as decreased rumen bacterial species and abundance.

Alternate feeding between high- and low- carbohydrate based diets improves the growth digestive capacity, liver glycometabolism for common carp (Cyprinus carpio)

Use of high-concentrate carbohydrate in fish diets will bring negative influence on the growth and glycometabolism. The current research, with common carp, was designed to investigate the efficiency of alternate feeding between high- and low- carbohydrate based diets in weakening these negative effects. Two control groups were, respectively, fed to the low carbohydrate diets (LC group, 100 g/kg cassava starch) and the high carbohydrate diets (HC group, 400 g/kg cassava starch) for 56 d, meanwhile other groups were subjected to every 1 d, 7 d, 14 d and 28 d alternation between the HC and LC diets, respectively (referred as R1, R7, R14 and R28). All experimental diets were fed to triplicate groups of 30 common carp (initial weight 1.17 ± 0.03 g). All four alternate groups achieved optimal growth and feed efficiency compared to the HC group. The R14 group possessed significantly higher weight growth rate, protein efficiency ratio, specific growth rate, intestinal index and condition factor, and significantly lower feed conversion ratio compared to the HC group. Fish in that group had higher protein content in whole body, higher expressions of growth hormone and insulin-like growth factor 1 in hepatopancreas and elevated intestinal activities of trypsin, amylase and alkaline phosphatase. Relative expressions of rapamycin, phosphatidylinositol 3-kinase, protein kinase B, Forkhead frame protein 1 A/1B, hexokinase, pyruvate kinase, glucokinase, phosphofructokinase, glucose transporter 2, glucose transporter 4, and sodium glucose cotransporter were also enhanced in the R14 group compared to HC group. Additionally, there was no difference in growth parameters between the LC group and four alternate groups. Alternate feeding between different carbohydrate level diets could enhance the growth, improve the digestive capacity and strengthen the glycometabolism to heighten the utilization ability of fish to high-carbohydrate diets, but this alternate cycle should be within reasonable limits. Briefly, it was concluded that the alternate cycle of 14 d was best.

Maternal pea fiber supplementation to a high calorie diet in obese pregnancies protects male offspring from metabolic dysfunction in adulthood.

We investigated the influence of maternal yellow-pea fiber supplementation in obese pregnancies on offspring metabolic health in adulthood. Sixty newly-weaned female Sprague-Dawley rats were randomized to either a low-calorie control diet (CON) or high calorie obesogenic diet (HC) for 6-weeks. Obese animals were then fed either the HC diet alone or the HC diet supplemented with yellow-pea fiber (HC + FBR) for an additional 4-weeks prior to breeding and throughout gestation and lactation. On postnatal day (PND) 21, 1 male and 1 female offspring from each dam were weaned onto the CON diet until adulthood (PND 120) for metabolic phenotyping. Adult male, but not female, HC offspring demonstrated increased body weight and feed intake vs CON offspring, however no protection was offered by maternal FBR supplementation. HC male and female adult offspring demonstrated increased serum glucose and insulin resistance (HOMA-IR) compared with CON offspring. Maternal FBR supplementation improved glycemic control in male, but not female offspring. Compared with CON offspring, male offspring from HC dams demonstrated marked dyslipidemia (higher serum cholesterol, increased number of TG-rich lipoproteins, and smaller LDL particles) which was largely normalized in offspring from HC + FBR mothers. Male offspring born to obese mothers (HC) had higher hepatic TG, which tended to be lowered (p = 0.07) by maternal FBR supplementation.Supplementation of a maternal high calorie diet with yellow-pea fiber in prepregnancy and throughout gestation and lactation protects male offspring from metabolic dysfunction in the absence of any change in body weight status in adulthood.

Early programming effects of a hyperglucidic diet on carbohydrate and lipid metabolism in gibel carp (Carassius gibelio)

Previous nutritional studies have shown that intermediate metabolism in early fish development is highly plastic, and thus we hypothesized that there may be an early programming effect of a hyperglucidic diet on carbohydrate utilization in gibel carp. To test our hypothesis, gibel carp CAS Ⅴ (mean body weight: 0.10 g) were fed a high-carbohydrate/low protein (HC/LP) or low carbohydrate/high protein (LC/HP) diet for three weeks, and then were fed with normal feed for 12 weeks and a hyperglucidic diet for one week. We found that early HC/LP stimulus inhibited growth performance but altered the expression of glucose metabolism genes. After long-term feeding on the normal diet, the effects of early HC/LP stimulus were eliminated; these involved plasma metabolites, hepatic cholesterol, glycogen and triglyceride content, and glucose and lipid metabolism. However, the early HC stimulus group showed a better ability to maintain plasma glucose hemostasis when again given the HC diet. The capacity of carbohydrate and lipid metabolism in juvenile gibel carp was improved in the early HC diet group, as indicated by upregulated expression of genes related to glycolysis, lipid transport (gk, akt, srebp1, acc, fas, hsl, and acly) and downregulated expression of genes involved in gluconeogenesis (fbpase). Moreover, the early HC diet significantly upregulated AKT protein expression levels. The DNA methylation levels of akt in the HC/LP group were significantly lower than those in the LC/HP group. Overall, the study suggests that early HC stimulus in juvenile gibel carp can result in better carbohydrate utilization through DNA methylation of critical elements in the insulin signaling pathway.

Comparing Self-Reported Dietary Intake to Provided Diet during a Randomized Controlled Feeding Intervention: A Pilot Study.

Systematic and random errors based on self-reported diet may bias estimates of dietary intake. The objective of this pilot study was to describe errors in self-reported dietary intake by comparing 24 h dietary recalls to provided menu items in a controlled feeding study. This feeding study was a parallel randomized block design consisting of a standard diet (STD; 15% protein, 50% carbohydrate, 35% fat) followed by either a high-fat (HF; 15% protein, 25% carbohydrate, 60% fat) or a high-carbohydrate (HC; 15% protein, 75% carbohydrate, 10% fat) diet. During the intervention, participants reported dietary intake in 24 h recalls. Participants included 12 males (seven HC, five HF) and 12 females (six HC, six HF). The Nutrition Data System for Research was utilized to quantify energy, macronutrients, and serving size of food groups. Statistical analyses assessed differences in 24 h dietary recalls vs. provided menu items, considering intervention type (STD vs. HF vs. HC) (Student's t-test). Caloric intake was consistent between self-reported intake and provided meals. Participants in the HF diet underreported energy-adjusted dietary fat and participants in the HC diet underreported energy-adjusted dietary carbohydrates. Energy-adjusted protein intake was overreported in each dietary intervention, specifically overreporting beef and poultry. Classifying misreported dietary components can lead to strategies to mitigate self-report errors for accurate dietary assessment.

Effects of diets differing in the concentrate-to-roughage ratio on meat quality and fatty acids composition in abomasal digesta and meat from thin-tail and fat-tail Brazilian ovine breeds

Fat-tail ovine breeds are known proposed to have distinctive lipid metabolism compared with thin-tail breeds. This hypothesis was investigated evaluating the effects of two types of diets (high vs low concentrate diet - HC vs LC) fed to two sheep breeds (fat-tail or thin-tail sheep) on fatty acid (FA) composition of abomasal digesta and meat quality. Forty lambs (20 fat-tail lambs and 20 thin-tail lambs) distributed in a randomized complete block design and fed two diets with different roughage: concentrate proportion. Breed slightly modified the FA profile of abomasal digesta and meat, but the 18:3 n-3 rumen biohydrogenation was increased in fat-tail lambs, resulting in a reduction of 18:3 n-3 meat proportion of fat-tail lambs fed HC diet and increased it in meat from thin tail lambs fed LC diet. The HC diet increased dry matter intake, and consequently FA intake, changing extensively the FA abomasal content and profile and increased the fat and protein content in meat. However, breed did not affect the meat fat content and BCFA, as proposed, but the fat-tail lambs decreased n-3 PUFA content and increased n-6 PUFA and t10–18:1 content (mg/100 g fresh meat), reducing the nutritional value of meat.

B-003 Decrease in Serum apoE-rich HDL-cholesterol May Be Associated With Cholesterol Accumulation in the Liver of Rats Fed A High-cholesterol Diet

Abstract Background Free cholesterol accumulation in the liver has been suggested to be one of risk factors for the progression of non-alcoholic fatty liver to non-alcoholic steatohepatitis. Therefore, a non-invasive approach to assess hepatic cholesterol accumulation in the early stage without elevation of liver enzymes (AST and ALT) may be useful in clinical setting. In this study, we show that serum apoE-rich HDL-cholesterol level is a possible indicator for predicting hepatic cholesterol accumulation in rats with diet-induced simple liver steatosis. Methods Male Sprague-Dawley rats (8 weeks) were purchased from Charles River Laboratories. Four different diets were obtained from Oriental Yeast; control diet (MF), high-fat diet (HF; 68% MF, 30% palm oil, and 2% cholic acid), high-cholesterol diet (HC; 95.5% MF, 2.5% cholesterol, and 2% cholic acid), and high-fat/high-cholesterol diet (HFC; 81.75% MF, 15% palm oil, 1.25% cholesterol, and 2% cholic acid). The rats were randomly divided into 4 groups and fed as follows. The control and HFC groups received the MF and HFC diets for 8 weeks, respectively. The HF/HC group received the HF diet for the first 4 weeks and the HC diet for the next 4 weeks. The HC/HF group received the HC diet first, then the HF diet. Blood and liver tissue specimens were collected under anesthesia. Total HDL fractions were isolated from whole sera by the polyethylene glycol precipitation method, and applied into a cation-exchange column (HiTrap SPHP, GE healthcare) for determining apoE-rich HDL-cholesterol levels. Correlations between variables were assessed with Spearman’s correlation coefficient (rs). Results Total cholesterol content of the liver was significantly higher in the HFC (11.1-fold, P &amp;lt; 0.001), HF/HC (9.1-fold, P &amp;lt; 0.001), and HC/HF (5.8-fold, P &amp;lt; 0.001) groups than the control group. Hepatic free cholesterol was also higher in the HFC (5.5-fold, P &amp;lt; 0.001), HF/HC (3.9-fold, P &amp;lt; 0.001), and HC/HF (3.3-fold, P &amp;lt; 0.001) groups. Hepatic triglycerides were slightly increased in the HC/HF (1.6-fold, P &amp;lt; 0.01) and HFC (1.5-fold, P &amp;lt; 0.05) groups. Serum apoE-rich HDL-cholesterol was significantly decreased in the HF/HC (0.21-fold, P &amp;lt; 0.001), HC/HF (0.25-fold, P &amp;lt; 0.001) and HFC (0.42-fold, P &amp;lt; 0.01) groups. The HFC group had significantly higher serum ALT (3.0-fold, P &amp;lt; 0.05) and AST (2.3-fold, P &amp;lt; 0.01) levels, compared with the control groups. There was a significant increase in hepatic mRNA expression of TNF-α (24.8-fold, P &amp;lt; 0.01) and TGF-β (3.8-fold, P &amp;lt; 0.001) only in the HFC group, indicating liver inflammation and stellate cell activation. To exclude the effects of hepatocyte injury on apoE-rich HDL metabolism, rats with ALT less than 100 U/mL (n = 16) were included in the following analysis. ApoE-rich HDL-cholesterol levels were significantly and inversely correlated with hepatic total cholesterol (rs = −0.535, P &amp;lt; 0.05) and free cholesterol (rs = −0.532, P &amp;lt; 0.05) levels but not with hepatic triglycerides. Furthermore, the ratio of ALT to apoE-rich HDL-cholesterol was more highly correlated with hepatic total cholesterol (rs = 0.626, P &amp;lt; 0.01) and free cholesterol (rs = 0.632, P &amp;lt; 0.01). There was no such correlation for apoE-poor HDL-cholesterol. Conclusion: The present observations suggest that serum apoE-rich HDL-cholesterol levels may be a useful indicator for cholesterol accumulation in the liver of cholesterol-fed rats.

Comparative study of carbohydrate levels on growth, oxidative stress and glucolipid metabolism of hybrid fish between Megalobrama amblycephala (♀) × Culter alburnus (♂) and Culter alburnus

The present study used hybrid fish (Megalobrama amblycephala ♀ × Culter alburnus ♂, abbreviated as BT) and topmouth culter (Culter alburnus, abbreviated as TC) as research subjects to assess and compare the effects of carbohydrate on the growth, oxidative stress and glucolipid metabolism of the two fish. The TC (initial weight, 13.10 ± 0.10 g) and BT (initial weight, 12.85 ± 0.13 g) were fed isonitrogenous (43% crude protein) and isolipidic (6.5% crude lipid) diets with carbohydrate levels of 10% (LC diet) and 30% (HC diet) for 11 weeks, respectively. The results showed that the HC diet resulted in a significant decrease in specific growth rate (SGR) of both fish. However, the SGR in BT was significantly higher than in TC, regardless of diet. Furthermore, HC diet significantly increased serum alanine transaminase (GPT) and hepatic malondialdehyde (MDA) content, decreased hepatic catalase (CAT) activity and resulted in increased hepatocyte volume, nucleus deficiency and nucleus deviation from the center of cytoplasm in both fish. However, BT had significantly higher glutathione peroxidase (GPx) activity and lower serum GPT and aspartate transaminase (GOT) content compared to TC. The HC diet induced significant increases in hepatosomatic index (HSI), liver lipid droplet area, liver glycogen, serum glucose (GLU) and triglyceride (TG) content in both fish. However, HSI and lipid droplet area were significantly higher in BT than in TC, while serum GLU and TG content were significantly lower in BT than in TC. Both fish can adapt to the HC diet by up-regulating the expression of glycolysis-related gene (glucokinase (gk)) and lipogenesis-related genes (acetyl-CoA carboxylase a (acca), fatty acid synthase (fas)). However, the expression levels of glucose transporter 2 (glut2), glycolysis-related gene (phosphofructokinase liver b (pfklb)) and lipogenesis-related genes (sterol regulatory element-binding protein 1 (srebp1), ATP citrate lyase a (aclya)) were increased only in BT fed HC diet. In summary, the BT liver has stronger glucose transport, glycolysis, and lipid tolerance compared to TC, thus exhibiting better glucose homeostasis and growth performance. It indicates that hybridization may help to produce new strain of fish with high carbohydrate utilization capacity.

Influence of the concentrate inclusion level in a grass silage–based diet on hepatic transcriptomic profiles in Holstein-Friesian dairy cows in early lactation

Excessive negative energy balance in early lactation is linked to an increased disease risk but may be mitigated by appropriate nutrition. The liver plays central roles in both metabolism and immunity. Hepatic transcriptomic profiles were compared between 3 dietary groups in each of 40 multiparous and 18 primiparous Holstein-Friesian cows offered isonitrogenous grass silage-based diets with different proportions of concentrates: (1) low concentrate (LC, 30% concentrate + 70% grass silage); (2) medium concentrate (MC, 50% concentrate + 50% grass silage), or (3) high concentrate (HC, 70% concentrate + 30% grass silage). Liver biopsies were taken from all cows at around 14 d in milk for RNA sequencing, and blood metabolites were measured. The sequencing data were analyzed separately for primiparous and multiparous cows using CLC Genomics Workbench V21 (Qiagen Digital Insights), focusing on comparisons between HC and LC groups. More differentially expressed genes (DEG) were seen between the primiparous cows receiving HC versus LC diets than for multiparous cows (597 vs. 497), with only 73 in common, indicating differential dietary responses. Multiparous cows receiving the HC diet had significantly higher circulating glucose and insulin-like growth factor-1 and lower urea than those receiving the LC diet. In response to HC, only the multiparous cows produced more milk. In these animals, bioinformatic analysis indicated expression changes in genes regulating fatty acid metabolism and biosynthesis (e.g., ACACA, ELOVL6, FADS2), increased cholesterol biosynthesis (e.g., CYP7A1, FDPS, HMGCR), downregulation in hepatic AA synthesis (e.g., GPT, GCLC, PSPH, SHMT2), and decreased expression of acute phase proteins (e.g., HP, LBP, SAA2). The primiparous cows on the HC diet also downregulated genes controlling AA metabolism and synthesis (e.g., CTH, GCLC, GOT1, ODC1, SHMT2) but showed higher expression of genes indicative of inflammation (e.g., CCDC80, IL1B, S100A8) and fibrosis (e.g., LOX, LUM, PLOD2). This potentially adverse response to a HC diet in physically immature animals warrants further investigation.

Effects of dietary forage-to-concentrate ratio on fat deposition, fatty acid composition, oxidative stability and mRNA expression of sirtuins genes of subcutaneous fat in sheep (Ovis aries)

ABSTRACT This study was carried out to evaluate the effects of dietary concentrate: forage (C: F) ratio on fat deposition, fatty acid composition, oxidative stability and mRNA expression levels of sirtuins genes associated with adipose tissue metabolism of subcutaneous fat in Black Tibetan sheep. Three diets with different C: F (HC: 70:30, IC:50:50 and LC: 30:70) were fed to fifteen weaned male lambs (2-month-old, 10.05 ± 0.96 Kg). The experiment lasted for 120 d. Five lambs from each group were randomly selected and slaughtered at the end of the experiment. The subcutaneous fat thicknesses increased with increasing concentrate level (P < 0.05). The concentration of polyunsaturated fatty acid (PUFA), C15:1 and C18:2n decreased by feeding the HC diet (P < 0.05). Both glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities significantly increased as dietary concentration levels decreased (P < 0.05). Additionally, SIRT1 and SIRT2 expression level was downregulated (P < 0.05) with increasing concentration supplementation (P < 0.05 and P < 0.05, respectively). In conclusion, the addition of 70% concentration supplementation is not recommended in Black Tibetan sheep, considering that no benefits were observed for nutrient utilization, oxidative stability or economic returns, while the supplementation of C: F at 50:50 proved to be suitable for finishing lambs.

1610-P: Fatty Acid–Binding Protein 4 as a Biomarker for Remission of Type 2 Diabetes

Elevated levels of circulating Fatty Acid Binding Protein 4 (FABP4), also named adipocyte FABP (A-FABP), are associated with obesity, diabetes mellitus, insulin resistance, hypertension, and cardiovascular risk. FABP4 is a protein found in high levels in both macrophages and adipocytes. Release of FABP4 from adipocytes via lipolysis, and release from macrophages during inflammation, plays a key role in development of insulin resistance and diabetes mellitus. We studied the effect of a high protein (HP; 30% protein, 40% carbohydrate, 30% fat) diet vs high carbohydrate (HC;15% protein, 55% carbohydrate, 30% fat) diet in patients recently diagnosed with Type 2 Diabetes (T2D). We determined the levels of circulating FABP4 and metabolic parameters in the HP vs HC groups at baseline and 6 months after consuming the respective diets. Participants (14) were randomized to a HP or HC diet for 6 months. All food was provided and designed for weight loss. After 6 months on the HP diet, 100% of the subjects had remission of T2D to Normal Glucose Tolerance (NGT), whereas only 16.6% of subjects on HC diet had remission of T2D. The HP diet group exhibited significant improvement in a) insulin sensitivity (p=0.001), b) inflammatory cytokines (p=0.001), C) cardiovascular risk factors (p=0.004) compared to the HC diet group at 6 months. Although weight loss in both groups was around 10% at 6 months, the HP group lost % fat mass, whereas, the HC group lost both % muscle and fat mass. Average level of FABP4 decrease after 6 months was 12,831 pg/ml in the 8 participants on the HP diet, compared to only a 1183 pg/ml average decrease after 6 months for the 6 HC participants. Conclusions: These data showed a significant decrease of circulating FABP4 in the HP but not HC diet group and suggests that a high protein diet could be an optimal way to reduce FABP4 levels in the blood. This could subsequently lower the risk of development/progression of insulin resistance, T2D, inflammation and cardiovascular risk conditions and serve as a biomarker. Disclosure F.B.Stentz: None. Funding AD Baskin

A high-concentrate diet induces mitochondrial dysfunction by activating the MAPK signaling pathway in the mammary gland of dairy cows

Subacute rumen acidosis can lead to mastitis in dairy cows. Mitochondrial dysfunction is closely related to the inflammatory response. This experiment was conducted to investigate the effects of a high-concentrate diet on mammary gland inflammation and mitochondrial damage in dairy cows. Twelve Holstein dairy cows in mid-lactation were randomly divided into 2 groups and fed a 40% concentrate (low concentrate, LC) diet or a 60% concentrate (high concentrate, HC) diet. Cows were fed individually, and the experiment lasted for 3 wk. After the experiment, mammary gland tissue, blood, and rumen fluid were collected. Compared with the LC diet, the HC diet significantly decreased rumen pH; the pH was <5.6 for more than 3 h. The HC diet also increased the concentration of LPS in the blood (7.17 ± 1.25 µg/mL vs. 12.12 ± 1.26 µg/mL), which indicated that feeding the HC diet successfully induced subacute rumen acidosis. The HC diet also increased the concentration of Ca2+ (34.80 ± 4.23 µg/g vs. 46.87 ± 7.24 µg/g) in the mammary gland and upregulated the expression of inflammatory factors IL-6 (1,128.31 ± 147.53 pg/g vs. 1,538.42 ± 241.38 pg/g), IL-1β (69.67 ± 5.86 pg/g vs. 90.13 ± 4.78 pg/g), and tumor necrosis factor-α (91.99 ± 10.43 pg/g vs. 131.75 ± 17.89 pg/g) in mammary venous blood. The HC diet also increased the activity of myeloperoxidase (0.41 ± 0.05 U/g vs. 0.71 ± 0.11 U/g) and decreased the content of ATP (0.47 ± 0.10 µg/mL vs. 0.32 ± 0.11 µg/mL) in the mammary gland. In addition, phosphorylation of JNK (1.00 ± 0.21 vs. 2.84 ± 0.75), ERK (1.00 ± 0.20 vs. 1.53 ± 0.31), and p38 (1.00 ± 0.13 vs. 1.47 ± 0.41) and protein expression of IL-6 (1.00 ± 0.22 vs. 2.21 ± 0.27) and IL-8 (1.00 ± 0.17 vs. 1.96 ± 0.26) were enhanced in cows of the HC group, indicating that the mitogen-activated protein kinase (MAPK) signaling pathway was activated. Compared with the LC diet, the HC diet reduced the protein expression of mitochondrial biogenesis-related proteins PGC-1α (1.00 ± 0.17 vs. 0.55 ± 0.12), NRF1 (1.00 ± 0.17 vs. 0.60 ± 0.10), TFAM (1.00 ± 0.10 vs. 0.73 ± 0.09), and SIRTI (1.00 ± 0.44 vs. 0.40 ± 0.10). The HC diet promoted mitochondrial fission and inhibited mitochondrial fusion by reducing protein expression of MFN1 (1.00 ± 0.31 vs. 0.49 ± 0.09), MFN2 (1.00 ± 0.19 vs. 0.69 ± 0.13), and OPA1 (1.00 ± 0.08 vs. 0.72 ± 0.07), and by increasing that of DRP1 (1.00 ± 0.09 vs. 1.39 ± 0.10), MFF (1.00 ± 0.15 vs. 1.89 ± 0.12), and TTC1/FIS1 (1.00 ± 0.08 vs. 1.76 ± 0.14), leading to mitochondrial dysfunction. The HC diet increased mitochondrial permeability by upregulating the protein expression of VDAC1 (1.00 ± 0.42 vs. 1.90 ± 0.44), ANT (1.00 ± 0.22 vs. 1.27 ± 0.17), and CYPD (1.00 ± 0.41 vs. 1.82 ± 0.43). Taken together, these results indicated that feeding the HC diet induced mitochondrial damage via the MAPK signaling pathway in the mammary gland of dairy cows.

High-concentrate diet elevates histone lactylation mediated by p300/CBP through the upregulation of lactic acid and induces an inflammatory response in mammary gland of dairy cows

High-concentrate diet can cause metabolic diseases, such as subacute ruminal acidosis (SARA), and secondary mastitis. To investigate the effect of SARA induced by high-concentrate diet on the lysine lactylation (Kla) and inflammatory responses in the mammary gland of dairy cows and the mechanism between them, we selected twelve mid-lactation Holstein cows with similar body conditions for modelling. They were randomly divided into two groups, fed a low-concentrate diet (LC) and a high-concentrate diet (HC) for 21 days. Our results showed that high-concentrate diet feeding significantly reduced ruminal pH, and the pH was below 5.6 for more than 3 h per day, indicating successful induction of the SARA model. Lactic acid concentrations in mammary gland and plasma were higher in the HC group than that in the LC group. HC diet feeding significantly up-regulated the expression levels of the Pan Kla, H3K18la, p300/CBP and monocarboxylate transporter 1 (MCT1) in the mammary gland. In addition, the mRNA expression levels of inflammatory factors were significantly regulated, including IL-1β, IL-1α, IL-6, IL-8, SAA3, and TNF-α, while the anti-inflammatory factor IL-10 was down-regulated. The mammary gland of HC group was structurally disorganized with incomplete glandular vesicles, with a large number of detached mammary epithelial cells and inflammatory cells infiltration. The up-regulation of TLR4, TNF-α, p-p65, and p-IκBα indicated that the TLR4/NF-κB signaling pathway was activated. In conclusion, this study found that HC diet feeding can induce SARA and increase the concentration of lactic acid in mammary gland and plasma. Then, lactic acid could be transported into cells by MCT1 and up-regulate the expression level of histone lactylation mediated by p300/CBP, and subsequently promote the activation of TLR4/NF-κB signaling pathway, ultimately causing inflammatory responses in the mammary gland.

A high-concentrate diet induces inflammatory injury via regulating Ca2+/CaMKKβ-mediated autophagy in mammary gland tissue of dairy cows.

Calmodulin-dependent protein kinase β (CaMKKβ) is closely related to Ca2+ concentration. An increase in Ca2+ concentration in the cytoplasm activates CaMKKβ, and activated CaMKKβ affects the activities of AMPK and mTOR and induces autophagy. A high-concentrate diet leads to Ca2+ disorder in mammary gland tissue. Therefore, this study mainly investigated the induction of mammary gland tissue autophagy by a high-concentrate diet and the specific mechanism of lipopolysaccharide (LPS)-induced autophagy in bovine mammary epithelial cells (BMECs). Twelve mid-lactation Holstein dairy cows were fed with a 40% concentrate diet (LC) and a 60% concentrate diet (HC) for 3 weeks. At the end of the trial, rumen fluid, lacteal vein blood, and mammary gland tissue were collected. The results showed that the HC diet significantly decreased rumen fluid pH, with a pH lower than 5.6 for more than 3 h, indicating successfully induction of subacute rumen acidosis (SARA). The mechanism of LPS-induced autophagy in BMECs was studied in vitro. First, the cells were divided into a Ctrl group and LPS group to study the effects of LPS on the concentration of Ca2+ and autophagy in BMECs. Then, cells were pretreated with an AMPK inhibitor (compound C) or CaMKKβ inhibitor (STO-609) to investigate whether the CaMKKβ-AMPK signaling pathway is involved in LPS-induced BMEC autophagy. The HC diet increased the concentration of Ca2+ in mammary gland tissue and pro-inflammatory factors in plasma. The HC diet also significantly increased the expression of CaMKKβ, AMPK, and autophagy-related proteins, resulting in mammary gland tissue injury. In vitro cell experiments showed that LPS increased intracellular Ca2+ concentration and upregulated protein expression of CaMKKβ, AMPK, and autophagy-related proteins. Compound C pretreatment decreased the expression of proteins related to autophagy and inflammation. In addition, STO-609 pretreatment not only reversed LPS-induced BMECs autophagy but also inhibited the protein expression of AMPK, thereby alleviating the inflammatory response in BMECs. These results suggest that inhibition of the Ca2+/CaMKKβ-AMPK signaling pathway reduces LPS-induced autophagy, thereby alleviating inflammatory injury of BMECs. Therefore, SARA may increase the expression of CaMKKβ by increasing Ca2+ levels and activate autophagy through the AMPK signaling pathway, thereby inducing inflammatory injury in mammary gland tissue of dairy cows.

Effects of Genistein on Lipid Metabolism, Antioxidant Activity, and Immunity of Common Carp (Cyprinus carpio L.) Fed with High-Carbohydrate and High-Fat Diets.

A 56-day feeding trial was conducted to investigate the effects of genistein on growth, lipid metabolism, antioxidant capacity, and immunity of common carp fed with high-carbohydrate or high-fat diets. Five diets were used to feed fish: control diet (5% fat; CO), high-fat diet (11% fat; HF), high-carbohydrate diet (45% carbohydrate; HC), and HF or HC diet with 500 mg/kg genistein (FG or CG). Results showed that final body weight (FW) and specific growth rate (SGR) were significantly reduced, but the supplementation with genistein resulted in higher values of FW and SGR than the HF or HC group. Both high carbohydrate and high fat belong to high-energy diets, which may promote lipid deposition. Genistein obviously decreased liver triglyceride (TG) content and alleviated hepatic fat vacuolation in the HF and HC groups. The expression of lipid metabolism genes (cpt-1 and atgl) was markedly higher in the FG group than in the HF group. The lipid synthesis-related genes (fas, acc, and pparγ) were elevated in high-energy diets but recovered to the control level or reduced after genistein treatments. With respect to fatty acid transporter genes, fatp increased in the FG group, and cd36 increased in the CG group. Furthermore, the antioxidant and immune indexes, such as total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), acid phosphatase (ACP), and lysozyme (LZM) activities, were decreased, while malonate aldehyde (MDA) content, activities of alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were enhanced in the HF and HC groups. The antioxidant and immunity values could be ameliorated by treatment with genistein. Moreover, the transcript levels of antioxidant-related genes (cat, gr, and nrf2) in the liver and anti-inflammatory factors (tgf-β and il-10) and lyz in the head kidney tissue were promoted, although the expression levels of proinflammatory factors (tnf-α and il-6) declined in the genistein supplementation group, which confirmed the antioxidant and immune-enhancing effects of genistein. Therefore, 500 mg/kg genistein could ameliorate the negative effects of high-energy diets on immunity.