L-Histidine attenuates NEFA-induced inflammatory responses by suppressing Gab2 expression.

Non-esterified fatty acids (NEFAs), key to energy metabolism, may become pathogenic at elevated levels, potentially eliciting immune reactions. Our laboratory's findings of reduced L-histidine in ketotic states, induced by heightened NEFA concentrations, suggest an interrelation with NEFA metabolism. This observation necessitates further investigation into the mitigating role of L-histidine on the deleterious effects of NEFAs. Our study unveiled that elevated NEFA concentrations hinder the proliferation of Bovine Mammary Epithelial Cells (BMECs) and provoke inflammation in a dose-responsive manner. Delving into L-histidine's influence on BMECs, RNA sequencing revealed 2124 genes differentially expressed between control and L-histidine-treated cells, with notable enrichment in pathways linked to proliferation and immunity, such as cell cycle and TNF signaling pathways. Further analysis showed that L-histidine treatment positively correlated with an increase in EdU-555-positive cell rate and significantly suppressed IL-6 and IL-8 levels (p < 0.05) compared to controls. Crucially, concurrent treatment with high NEFA and L-histidine normalized the number of EdU-555-positive cells and cytokine expression to control levels. Investigating the underlying mechanisms, Gab2 (Grb2-associated binder 2) emerged as a central player; L-histidine notably reduced Gab2 expression, while NEFA had the opposite effect (p < 0.05). Gab2 overexpression escalated nitric oxide (NO) production and IL6 and IL8 expression. However, L-histidine addition to Gab2-overexpressing cells resulted in NO concentrations indistinguishable from controls. Our findings collectively indicate that L-histidine can counteract NEFA-induced inflammation in BMECs by inhibiting Gab2 expression, highlighting its therapeutic potential against NEFA-related metabolic disturbances.

UFL1 regulates cellular homeostasis by targeting endoplasmic reticulum and mitochondria in NEFA-stimulated bovine mammary epithelial cells via the IRE1α/XBP1 pathway.

Elevated levels of NEFA caused by negative energy balance in transition cows induce cellular dyshomeostasis. Ubiquitin-like modifier 1 ligating enzyme 1 (UFL1) can maintain cellular homeostasis and act as a critical regulator of stress responses besides functioning in the ubiquitin-like system. The objective of this study was to elucidate the UFL1 working mechanism on promoting cellular adaptations in bovine mammary epithelial cells (BMECs) in response to NEFA challenge, with an emphasis on the ER and mitochondrial function. The results showed that exogenous NEFA and UFL1 depletion resulted in the disorder of ER and mitochondrial homeostasis and the damage of BMEC integrity, overexpression of UFL1 effectively alleviated the NEFA-induced cellular dyshomeostasis. Mechanistically, our study found that UFL1 had a strong interaction with IRE1α and could modulate the IRE1α/XBP1 pathway of unfolded protein response in NEFA-stimulated BMECs, thereby contributing to the modulation of cellular homeostasis. These findings imply that targeting UFL1 may be a therapeutic alternative to relieve NEB-induced metabolic changes in perinatal dairy cows.

Comparative Metabolomic Profiling of L-Histidine and NEFA Treatments in Bovine Mammary Epithelial Cells.

Non-esterified fatty acids (NEFAs) are pivotal in energy metabolism, yet high concentrations can lead to ketosis, a common metabolic disorder in cattle. Our laboratory observed lower levels of L-histidine in cattle suffering from ketosis, indicating a potential interaction between L-histidine and NEFA metabolism. This relationship prompted us to investigate the metabolomic alterations in bovine mammary epithelial cells (BMECs) induced by elevated NEFA levels and to explore L-histidine's potential mitigating effects. Our untargeted metabolomic analysis revealed 893 and 160 metabolite changes in positive and negative models, respectively, with VIP scores greater than 1 and p-values below 0.05. Notable metabolites like 9,10-epoxy-12-octadecenoic acid were upregulated, while 9-Ethylguanine was downregulated. A pathway analysis suggested disruptions in fatty acid and steroid biosynthesis pathways. Furthermore, L-histidine treatment altered 61 metabolites in the positive model and 34 in the negative model, with implications for similar pathways affected by NEFA. Overlaying differential metabolites from both conditions uncovered a potential key mediator, 1-Linoleoylglycerophosphocholine, which was regulated in opposite directions by NEFA and L-histidine. Our study uncovered that both NEFA L- and histidine metabolomics analyses pinpoint similar lipid biosynthesis pathways, with 1-Linoleoylglycerophosphocholine emerging as a potential key metabolite mediating their interaction, a discovery that may offer insights for therapeutic strategies in metabolic diseases.

The Protective Role of Vitamin E against Oxidative Stress and Immunosuppression Induced by Non-Esterified Fatty Acids in Bovine Peripheral Blood Leukocytes.

High levels of non-esterified fatty acids (NEFAs) during the transition period lead to increased oxidative stress and immunosuppression in cows. Feeding them a vitamin-E-supplemented diet reduces reactive oxygen species (ROS) levels in the blood and diminishes immunosuppression in the transition period. However, whether the restoration of immune cell function occurs through the direct action of vitamin E in cells is still a topic that requires further discussion. Therefore, in this experiment, we aimed to investigate the effect of NEFAs on peripheral blood leukocytes (PBLs) and whether vitamin E mitigates the impact of NEFAs. We employed three groups: (1) blank, (2) NEFA only, and (3) pre-culturing with vitamin E before NEFA treatment (VENEFA). In peripheral blood mononuclear cells (PBMCs), there were no differences in vitamin E content among the three groups. However, in the vitamin E pre-treatment group, the vitamin E levels of polymorphonuclear neutrophils (PMNs) were significantly higher than those in the other two groups. NEFA levels increased malondialdehyde (MDA) levels in PBMCs, but pre-treatment with vitamin E reduced accumulation of MDA levels. Regarding the expression of proinflammatory genes, NEFAs increased the expression of interleukin-1ß in PBMCs and colony-stimulating factor 2 in PMNs. Vitamin E pre-treatment restored the increase in interleukin-1ß levels caused by NEFAs in PBMCs. None of the groups affected the phagocytosis of PMNs. Few studies have confirmed that NEFAs cause oxidative stress in bovine PBLs. In summary, this study found that NEFAs induce oxidative stress in PBLs and alter the expression of inflammation-related genes; meanwhile, vitamin E can reduce some of the effects caused by NEFAs. This result may suggest that vitamin E can assist bovine PBLs in resisting the immune suppression caused by an NEB during the transition period.

MANP in Hypertension With Metabolic Syndrome: Proof-of-Concept Study of Natriuretic Peptide-Based Therapy for Cardiometabolic Disease.

Hypertension and metabolic syndrome frequently coexist to increase the risk for adverse cardiometabolic outcomes. To date, no drug has been proven to be effective in treating hypertension with metabolic syndrome. M-atrial natriuretic peptide is a novel atrial natriuretic peptide analog that activates the particulate guanylyl cyclase A receptor. This study conducted a double-blind, placebo-controlled trial in 22 patients and demonstrated that a single subcutaneous injection of M-atrial natriuretic peptide was safe, well-tolerated, and exerted pleiotropic properties including blood pressure-lowering, lipolytic, and insulin resistance-improving effects. (MANP in Hypertension and Metabolic Syndrome [MANP-HTN-MS]; NCT03781739).

Effects of dietary chromium supplementation on blood biochemical parameters in dairy cows: A multilevel meta-analytical approach.

Chromium (Cr) has been reported to modulate blood biochemistry in dairy cows. However, there is a discrepancy in the literature regarding the effects of dietary Cr supplementation on various blood parameters. This meta-analysis aimed to evaluate the effects of Cr supplementation in dairy cows on blood glucose, insulin, glucagon, nonesterified fatty acid (NEFA), cortisol, and serum total protein (STP) concentrations. Following relevant literature data extraction, a 3-level meta-analytical random effect model was fitted to the data expressed as standardized mean difference (SMD) of outcome measures of control versus Cr-supplemented cows (i.e., difference in mean between control and treatment group or pooled standard deviation). The SMD can be categorized as having a small effect (0.20), a moderate effect (0.50), and a large effect (0.80). The meta-regression identified the potential sources of heterogeneity, including the body weight of cows, experimental duration/duration of Cr supplementation, blood sampling time (3 wk before parturition until 4 wk after parturition categorized as the transition period, else as the nontransition period), and form of Cr complexes. Blood glucose did not differ significantly between control and Cr-supplemented cows with an estimated SMD of µ = 0.0071 (95% confidence interval [CI]: -0.212 to 0.226). The effect of Cr supplementation on blood insulin was also nonsignificant with an SMD of µ = 0.0007 (95% CI: -0.191 to 0.193). Cows receiving Cr supplements had significantly higher levels of glucagon than controls (95% CI: 0.116 to 0.489), with an estimated SMD = 0.303. Combined transition and nontransition data suggest Cr supplementation did not affect the concentration of NEFA. However, in transition cows, Cr supplementation significantly decreased blood NEFA levels as compared with controls (95% CI: -0.522 to -0.0039), with estimated SMD = -0.263. The estimated SMD was µ = -0.1983 (95% CI: -0.734 to 0.337) for cortisol and -0.0923 (95% CI: -0.316 to 0.131) for total protein. In summary, Cr supplementation in the transition cows decreased NEFA concentration. Blood glucose, insulin, cortisol, and STP concentrations were unaffected. However, Cr supplementation increased glucagon concentration.

The impact of dairy matrix structure on postprandial lipid responses.

This review presents evidence related to the postprandial responses after consumption of dairy products focusing on the effect of the dairy matrix and lipid response, which was also presented as part of a speech at the Nutrition Society Winter Conference, January 2023. The key findings are that the dairy product(s) that differentiate from others in the postprandial TAG response are products with a semi-solid structure. There were no differences in lipid responses between cheese and butter. The main factors viscosity, fat globule size and milk fat globule membrane do not seem to explain the effect of the dairy matrix in the acute postprandial response. In summary, it is very difficult to investigate the effects of the dairy matrix per see and with the few studies conducted to date, no clear cause and effect can be established. Future research should focus on the semi-solid dairy matrix, and studies investigating specifically the yoghurt matrix are warranted.

Effect of postpartum drenching on plasma parameters of cows at a large-scale dairy farm.

The aim of the present study was to explore the influence of postpartum drenching with a feed additive on the plasma concentration of biochemical parameters while factoring in prepartum rumination times (RT). One hundred and sixty-one cows were fitted with a Ruminact© HR-Tag approximately 5 days before calving. Drenching and control groups were established based on calving dates. Animals in the drenched group were treated three times (Day 1/day of calving/, Day 2, and Day 3 postpartum) using a feed additive containing calcium propionate, magnesium sulphate, yeast, potassium chloride and sodium chloride mixed in approximately 25 L of lukewarm tap water. Blood samples were collected on Days 1, 2, 3, 7 and 12. Cows with below the average RT were categorised as "low rumination" and those above it as "high rumination" animals. Drenching decreased the plasma concentrations of total protein, urea and creatinine and increased the levels of alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and chloride. Low rumination time prepartum resulted in higher concentrations of beta-hydroxybutyrate, total protein and activities of alkaline phosphatase and GGT, while it decreased the activity of ALT and the concentrations of calcium, magnesium, sodium and potassium. The day of lactation had an effect on all parameters except for potassium.

Higher circulating levels of non-esterified fatty acids are associated with faster kidney function decline in post-menopausal women with type 2 diabetes: a pilot prospective study.

AIMS: Currently, there is little and inconsistent evidence regarding the possible adverse effects of circulating levels of non-esterified fatty acids (NEFA) on kidney function decline in patients with type 2 diabetes mellitus (T2DM). METHODS: We followed for a median of 4.6 years 85 post-menopausal women with non-insulin-treated T2DM and preserved kidney function at baseline. Serum NEFA concentrations were measured using an enzymatic colorimetric method. Glomerular filtration rate (eGFR) was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. RESULTS: Enrolled patients had a baseline mean eGFRCKD-EPI of 83 ± 12 mL/min/1.73 m2 and a median serum NEFA concentration of 662 uEq/L (interquartile range 524-842 uEq/L). During the follow-up period, 13 patients developed kidney function decline at follow-up (defined as an eGFRCKD-EPI decline ≥ 30% from baseline). In Cox proportional hazards regression analyses, higher serum NEFA levels were significantly associated with an increased risk of developing kidney function decline (adjusted-hazard ratio 3.67, 95% CI 1.64-8.22, p < 0.001; for each 1-SD increment, i.e., 262 uEq/L), even after adjustment for waist circumference, hemoglobin A1c, C-reactive protein, HOMA-estimated insulin resistance, hypertension, dyslipidemia, microalbuminuria, baseline eGFRCKD-EPI, as well as temporal changes in HbA1c levels or the use of renin-angiotensin system inhibitors over the follow-up. CONCLUSIONS: The findings of this exploratory prospective study show that in post-menopausal women with T2DM and preserved kidney function at baseline, higher circulating levels of NEFA were strongly associated with a faster kidney function decline, even after adjustment for established renal risk factors and potential confounders.

Association of vitamin D status with redox balance and insulin resistance and its predicting ability for subclinical pregnancy toxemia in pregnant sheep.

The study aimed to evaluate the role of vitamin D on redox balance, insulin resistance and its predicting value for subclinical pregnancy toxemia (SPT) in pregnant ewes. At four weeks pre-lambing, fifteen healthy pregnant ewes were divided into two groups, ewes with sufficient vitamin D (25-hydroxy-vitamin D (25VitD) (SVD, n = 9) and ewes with insufficient 25VitD (ISVD, n = 6). Blood samples were collected at 4 weeks pre-lambing using modified frequently sampled intravenous glucose tolerance test for the estimation of various metabolites. The baseline glucose, insulin, non-esterified fatty acid (NEFA), fructosamine, beta-hydroxy butyric acid (ß-BHA), calcium, phosphorus concentration and total oxidant status (TOS) did not differ significantly between the two groups, however, total antioxidant capacity (TAC) was significantly (p = 0.031) low in ISVD ewes. Area under the curve for glucose, insulin, elimination rate of glucose and peak insulin also did not differ significantly between the two groups. Correlation analysis revealed, positive association of 25VitD with fructosamine, calcium and TAC, and negative correlation with NEFA and TOS. Subsequent blood sampling at 2 weeks pre-lambing and at lambing showed significant difference in NEFA (p = 0.001), ß-HBA (p = 0.001), and fructosamine(p = 0.012) between the two groups. A significant time x group interaction was observed in NEFA (p = 0.019), ß-HBA (p = 0.031), and fructosamine (p = 0.026) concentration. The NEFA concentrations were increased and fructosamine decreased at 2 weeks pre-lambing and at lambing along with significantly increased ß-HBA at 2 weeks pre-lambing in ISVD compared to SVD. Taking 0.8 mmol/L ß-HBA as the cut off limit for SPT, ISVD ewes had higher odds of developing SPT two weeks prior to lambing (OD 16.00; p = 0.042) and at lambing (OD 10; p = 0.077). This study concludes that 25VitD significantly influence redox balance and energy profile and serves as a valuable predictor for SPT in pregnant sheep.

NEFA Dynamics in Adults With Severe Obesity and Insulin Resistance: No Coupling to the rs9939609 FTO Risk Allele.

Context: The FTO gene is highly expressed in adipose tissues; however, whether nonesterified fatty acids (NEFA) dynamics are impacted by FTO has not been rigorously tested for in a uniformly obese study population comprising both sexes. Objective: To test for associations of the rs9939609 FTO risk allele with NEFA suppression. Methods: We investigated 97 subjects with severe obesity but without diabetes, having genotype TT (n = 32), AT (n = 31), or AA (n = 34) in a cross-sectional observation study. NEFA suppression was assessed from a low-dose hyperinsulinemic euglycemic clamp with glucose-tracer as well as from the response to a standardized meal. Insulin sensitivity was assessed by hepatic and total insulin sensitivity measurements in the clamp and by the Matsuda index during the meal. Variables of possible importance for NEFA dynamics were primarily assessed by linear regression. Results: No genotype associations with fasting or suppressed NEFA were found, whether in the clamp or meal situation (P > .7 for all comparisons). Independent of genotype, higher fasting concentrations of NEFA and larger NEFA suppression were found in female compared with male subjects. Fasting NEFA or degree of suppression were not associated with total fat mass or body mass index. The respiratory quotient was negatively associated with NEFA suppression. Conclusion: In a gender-mixed adult population of obese individuals, an FTO obesity-risk allele did not affect fasting NEFA nor suppression thereof. These negative results on NEFA dynamics appear strengthened by the documentation of gender influence and associations with parameters reflective of insulin resistance.

Changes in Body Reserves, Non-Esterified Fatty Acids, and Leptin during the Reproductive Lifespan of the Rabbit Female.

The aim of this work is to study changes in body weight, perirenal fat thickness (PFT), and non-esterified fatty acid (NEFA) and leptin concentrations throughout the reproductive life of the rabbit female and their correlations when a semi-intensive reproductive rhythm is applied. A total of 46 lactating females were used. Body weight, PFT, and NEFA and leptin concentration were recorded at 12 weeks of age, at first mating and delivery, and at second, third, and fourth mating, 12th d of gestation, and delivery. The highest body weight was detected on the 12th d of any gestation, around 4280 g, and the lowest weight was at delivery, around 4030 g. PFT increased until third mating. NEFA and leptin concentration showed a cyclical pattern throughout the reproductive lifespan of the females. NEFAs presented the highest concentration at delivery within each reproductive cycle and levels decreased over the course of the deliveries (0.423 mmol/L at first delivery, 0.406 mmol/L at second delivery, 0.371 mmol/L at third delivery, and 0.309 mmol/L at fourth delivery). Similar NEFA concentrations at mating and on the 12th d of gestation were obtained. Leptin showed the highest concentrations at mating within each reproductive cycle. Leptin decreased between mating and delivery in all reproductive cycles and it was close to 1 ng/mL HE. Low or null correlations were shown between body weight, PFT, and NEFA and leptin concentration at mating, 12th d of gestation, and delivery. In conclusion, females are able to maintain a semi-intensive reproductive rhythm across four parities weighing around 4 kg from first mating. Females had an increased perirenal fat thickness until third delivery, and their NEFA concentration was maximum at delivery and leptin concentration was maximum at mating. Body weight, PFT, and NEFA and leptin concentration should be measured during critical moments of reproductive life in order to determine body condition and energy mobilization, due to their low or null correlations.

Association of precalving serum NEFA concentrations with postpartum diseases and reproductive performance in multiparous Holstein cows: Cut-off values.

BACKGROUND: High concentrations of NEFA relative to a defined reference or 'cut-point' values before calving can predict the risk of specific or collective periparturient disease events. OBJECTIVES: A field-based cohort study was conducted to evaluate the value and critical points of serum nonesterified fatty acids (NEFA) at the precalving time to predict the occurrence of postpartum diseases and reproductive performance in dairy cows. METHODS: Blood samples were taken from 521 high-yielding dairy cows at 1 week (±3 days) before calving and NEFA levels were measured. Health and reproduction information of each cow includes dystocia, retained placenta, milk fever, metritis, mastitis, pregnancy in the first insemination and pregnancy in the first two inseminations, and culling in the first 60 days of lactation and milk production. RESULTS: Our results show that there are significant relationships between precalving NEFA with the probability of pregnancy at the first and the first two inseminations after calving. The cows that had NEFA concentrations less than 0.5 mmol/L at the last week of pregnancy were 3.51 and 3.15 times more likely to be pregnant at first insemination and the first two inseminations, respectively. Also, our results showed that there are significant relationships between precalving NEFA concentration and the likelihood of dystocia and milk fever. The probability of dystocia and milk fever occurrence were 2.56 and 1.91 times greater in those cows that had NEFA concentrations more than 0.3 mmol/L, respectively. CONCLUSIONS: The present results indicated that Increasing NEFA during the prepartum period could adversely affect the reproductive efficiency of dairy cows.

Predicting Pregnancy Outcome in Dairy Cows: The Role of IGF-1 and Progesterone.

The purpose of this study was to determine the link between insulin-like growth factor 1 (IGF-1), progesterone (PROG), non-esterified fatty acids (NEFAs), ß-hydroxybutyrate (BHB), and glucose (GLU) and pregnancy probability after the first artificial insemination (AI) and during the first 100 days in milk (DIM), during the critical transition period. We determined levels of serum IGF-1, PROG, NEFA, BHB, and GLU in Holstein dairy cows via ELISA, using blood samples collected 7 days before parturition (DAP) until 21 days postparturition (DPP). The group was split into cows diagnosed pregnant at 100 DIM (PREG) and those that did not conceive at 100 and 150 DIM (NPREG). Serum IGF-1 and PROG median levels at 7 DAP were significantly higher in PREG vs. NPREG (p = 0.029), the only statistically significant differences across the subgroups. At 7 DAP, IGF-1 levels within the initial group showed a strong negative correlation with PROG (r = -0.693; p = 0.006), while for the PREG subgroup, the IGF-1 levels exhibited a very strong positive correlation with GLU (r = 0.860; p = 0.011) and NEFA (r = 0.872; p = 0.013). IGF-1 and PROG levels detected at 7 DAP may be useful to predict pregnancy at 100 DIM. The positive correlation of NEFA and GLU levels during the transition period demonstrates that the initial group is not in NEB; thus, the NEFA level was not a decisive factor for reproduction success.

Essential Fatty Acid Deficiency Associates with Growth Faltering and Environmental Enteric Dysfunction in Children.

Environmental enteric dysfunction (EED) is characterized by intestinal inflammation, malabsorption and growth-faltering in children with heightened exposure to gut pathogens. The aim of this study was to characterize serum non-esterified fatty acids (NEFA), in association with childhood undernutrition and EED, as potential biomarkers to predict growth outcomes. The study comprised a cohort of undernourished rural Pakistani infants (n = 365) and age-matched controls followed prospectively up to 24 months of age. Serum NEFA were quantified at ages 3-6 and 9 months and correlated with growth outcomes, serum bile acids and EED histopathological biomarkers. Serum NEFA correlated with linear growth-faltering and systemic and gut biomarkers of EED. Undernourished children exhibited essential fatty acid deficiency (EFAD), with low levels of linoleic acid and total n-6 polyunsaturated fatty acids, compensated by increased levels of oleic acid and increased elongase and desaturase activities. EFAD correlated with reduced anthropometric Z scores at 3-6 and 9 months of age. Serum NEFA also correlated with elevated BA and liver dysfunction. Essential fatty acid depletion and altered NEFA metabolism were highly prevalent and associated with acute and chronic growth-faltering in EED. The finding suggests that targeting early interventions to correct EFAD and promote FA absorption in children with EED may facilitate childhood growth in high-risk settings.

Serum growth differentiation factor-15 and non-esterified fatty acid levels in patients with coronary artery disease and hyperuricemia.

BACKGROUND: High serum NEFA and GDF-15 are risk factors for CAD and have been linked to detrimental cardiovascular events. It has been hypothesized that hyperuricemia causes CAD via the oxidative metabolism and inflammation. The current study sought to clarify the relationship between serum GDF-15/NEFA and CAD in individuals with hyperuricemia. METHODS: Blood samples collected from 350 male patients with hyperuricemia(191 patients without CAD and 159 patients with CAD, serum UA > 420 µmol/L) to measure serum GDF-15 and NEFA concentrations with baseline parameters. RESULTS: Serum circulating GDF-15 concentrations(pg/dL) [8.48(6.67,12.73)] and NEFA levels(mmol/L) [0.45(0.32,0.60)] were higher in hyperuricemia patients with CAD. Logistic regression analysis revealed that the OR (95% CI) for CAD were 10.476 (4.158, 26.391) and 11.244 (4.740, 26.669) in quartile 4 (highest) respectively. The AUC of the combined serum GDF-15 and NEFA was 0.813 (0.767,0.858) as a predictor of whether CAD occurred in male with hyperuricemia. CONCLUSIONS: Circulating GDF-15 and NEFA levels correlated positively with CAD in male patients with hyperuricemia and measurements may be a useful clinical adjunct.

Effect of body condition loss in early lactation Holstein cows on plasma IGF-I, prolactin and NEFA during breeding period and its association with some reproductive indices.

The associations between early lactation changes in the body condition score (BCS) and mid-lactation levels of blood insulin-like Growth Factor-I (IGF-1), prolactin, insulin, nonesterified fatty acids (NEFA), milk production and some reproductive indices were investigated. Monthly milk yield and BCS were recorded. Blood samples were collected on days 60, 90, and 120 (±5 days) of lactation. Twelve and 17 cows showed BCS losses ≤0.75 and >0.75 on day 60, respectively. BCS losses ≤0.75 till day 60 after calving enhanced the IGF-I concentration on day 90 (57.8 ± 10.7 vs. 35.6 ± 17.8 ng/mL; p = .001). The differences in blood metabolites were prominent on day 90. Trends of insulin changes between day 60 BCS (p = .04) groups were different. Inverse correlations were detected between IGF-I and NEFA (-0.6, p = .001), IGF-I and milk production (-0.4, p = .05), NEFA and prolactin (-0.8, p < .001) on day 90. Higher percentages of cows with BCS loss >0.75 (day 60) showed their first heat after day 40 postpartum. In conclusion, irrespective of BCS at the time of breeding, the level of BCS loss during the first 60 days of lactation may affect further reproductive performance due to prolonged alterations of IGF-I, NEFA, prolactin and insulin levels. The extent of postpartum BCS loss may be a predictor of the metabolic status of cows during mid-lactation.

Nutritional Metabolites as Biomarkers of Previous Feed Intake in European Rabbit (Oryctolagus cuniculus): Applications on Conservation.

European wild rabbit (Oryctolagus cuniculus) populations have drastically reduced, and recently, rabbits have been classed as "endangered" by the IUCN. This animal plays an important ecological role in Mediterranean ecosystems and its introduction could significantly contribute to ecological restoration. Rabbits have high nutrient requirements that apparently cannot be covered in all ecosystems, and there are clues that nutrition can limit their abundance and density. On the other hand, some studies reflect the effects of food availability on the metabolomic status of other animal species, but there are no specific studies on this keystone species. The main aim of this work is to find biomarkers to assess the previous levels of ingestion of European rabbits (Oryctolagus cuniculus). To address this gap, gastric content and blood samples were collected from European rabbits (n = 99) in a Mediterranean area for the analysis of glucose, non-esterified fatty acids (NEFA), plasmatic urea nitrogen (PUN), albumin, glutamate and total protein metabolites. Depending on their previous feed intake (gastric content and the ratio between the gastric content and the weight of the animal), the animals were divided into two groups (lower and normal previous feed intake). Our work shows that the metabolomic profiles of the animals were affected. Levels of glucose (+82%; p = 0.0003), NEFA (−61%; p = 0.0040) and PUN (+139%; p < 0.001) were different in the animals with lower previous feed intake than the animals with normal previous feed intake. This work summarises that metabolic phenotype can be interesting when seeking to discover the limiting nutrients and food availability in diets that could affect the ecological fitness and conservation of European wild rabbits. It is important to mention that in this work, only the effects on six different metabolites have been analysed and more studies are necessary to complement the knowledge of possible metabolites that indicate the level of ingestion in this species and others. These (and new) biomarkers could be used as a tool to provide information about individual or population characteristics that other physiological parameters cannot detect, improving the conservation physiology field.

SNPs in apolipoproteins contribute to sex-dependent differences in blood lipids before and after a high-fat dietary challenge in healthy U.S. adults.

BACKGROUND: The effect of genetic polymorphisms on fasting blood lipid levels have been widely studied but the effects of these within the context of a high-fat meal challenge remain less characterized. The current study aimed to investigate the association of SNPs in lipoprotein-related genes with blood lipid profiles in healthy adults in the U.S. METHODS: Subjects (n = 393) between 18-66 years of age with BMIs ranging from 18.5-45 kg/m2 were enrolled the cross-sectional Nutritional Phenotyping Study. Among them, 349 subjects (men: 48%; women: 52%) gave consent for genotyping. SNPs in APOA5, APOB, APOC3, APOE, and LDLR were assessed. The association between lipid markers and genotypes was tested separately for each SNP with analysis of variance (ANOVA), adjusted for sex, age, and BMI. We also examined two-factor interactions between SNPs and sex, age, or BMI. RESULTS: Women carrying the C allele of rs3135506 in APOA5 or men carrying the C allele of rs429358 in APOE had reduced HDL-cholesterol levels during fasting and postprandially. The C allele in APOE was also correlated to increased LDL-C levels. The TT genotype of rs2854116 in APOC3 was associated with elevated total cholesterol. Additive effect of the risk alleles of APOA5 and APOE or APOC3 and APOE was detected. Nevertheless, the tested SNPs had little impact on the postprandial triglyceride responses to the high-fat challenge meal. We found no significant effects of SNPs in APOB (rs1042034) or LDLR (rs2228671) on triglycerides, cholesterol, or free fatty acid levels. CONCLUSIONS: In healthy adults, fasting and postprandial cholesterol levels are strongly correlated with the tested APOA5, APOE, and APOC3 genotypes. Sex contributes to the genetic impact of the tested SNPs on lipid profiles. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02367287. Registered February 20, 2015, https://clinicaltrials.gov/ct2/show/NCT02367287 .