Plasma Nonesterified Fatty Acids Research Articles

235 Evaluation of an exogenous fibrolytic enzyme combination in forage-based growing diets fed to growing beef cattle

Abstract Crossbred steers [n = 73; 287±19 kg initial body weight (BW)] were used in an 84-d growing study to investigate the effects of feeding an exogenous xylanase and cellulase combination product (EFE) and wheat straw (WS) inclusion level on the growth performance of growing beef cattle. Treatments were arranged as a 2 × 2 factorial with two levels of WS, either 5% (low; LS) or 15% (high; HS) of diet dry matter, and two inclusion rates of exogenous fibrolytic enzymes, 0 (none; N) or 750 g/ton (enzyme; E; Bovizyme CX; Danisco Animal Nutrition and Health; Wilmington, DE) of diet. Body weights and blood samples were collected every 28 d. Individual intake data were collected using an automated feeding system (Insentec Roughage Intake Control, Hokofarm B.V., Marknesse, The Netherland). Average daily gain (ADG), dry matter intake (DMI), gain to feed ratio (G:F), plasma glucose (GLU), plasma non-esterified fatty acids (NEFA), and plasma urea nitrogen (PUN) were analyzed using PROC MIXED (SAS Ins. Inc., Cary, N.C.). Animal was the experimental unit and fixed effects included blocks of body weight (n = 3) and original source of steers (n = 2). The model included the level of WS (LS, HS), level of EFE (N or E), and WS × EFE interactions. There were no WS × EFE interactions (P ≥ 0.31) for all measured traits. Supplementing EFE resulted in no differences (P ≥ 0.16) for ending BW, ADG, DMI, G:F, NEFA, and PUN. However, within HS diet, inclusion of E numerically increased ADG by 0.05 kg/d compared with N (1.29 vs. 1.24 kg/d; HSE vs. HSN, respectively; P > 0.31). Steers consuming E diets tended to have greater GLU compared with N (4.92 vs. 4.80 µmol/L, respectively; P = 0.10). Between levels of straw inclusion, ending BW was greater for steers consuming LS diet compared with HS diet (413 vs. 393 kg, respectively; P < 0.0001). Resulting in greater ADG for steers consuming LS diet compared with HS diet (1.49 vs. 1.26 kg, respectively; P < 0.01). Dry matter intake was greater for steers consuming LS diet than HS diet (9.06 vs. 8.33 kg, respectively; P < 0.01). Therefore, G:F was improved for steers consuming LS diet compared with HS diet (0.165 vs. 0.151, respectively; P < 0.01). Steers consuming LS diet had decreased NEFA compared with HS diet (311 vs. 376 µmol/L, respectively; P < 0.01). Results from this study indicate that regardless of the inclusion level of WS, supplementing growing steers with EFE did not influence growth performance. However, replacing ten percent of corn silage with WS reduced the energy concentration of the diet, decreasing growth performance.

Feed restriction affects milk performances and decreases milk lipolysis in dairy ewes

Spontaneous lipolysis results in the breakdown of milk fat by the lipoprotein lipase (LPL; EC: 3.1.1.34), an enzyme present in milk. Free fatty acids (FFA) and by-products released in milk during lipolysis can alter both the organoleptic value of milk (off-flavours release) and technological properties of dairy products (decrease in creaming capabilities). Current climate change is having significant impacts on the feeding of grazing animals, with negative consequences on the availability and quality of grass. We and others have demonstrated that dietary restriction increases milk lipolysis in the cow species. However, no data about the impact of feed restriction on milk lipolysis is available in the ewe species. Thus, this paper aims to investigate the effect of feed restriction on milk characteristics with regard to lipolysis values in dairy ewes. Two groups of 24 multiparous Lacaune ewes in mid-lactation received a “non-restricted” (NON RESTR) control diet (100 % of ad libitum DM intake) or a “restricted” (RESTR) diet (65 % of ad libitum DM intake) according to a 2 X 2 crossover design. Milk gross composition together with lipolysis analyses were performed. Blood samples were also screened for metabolites or hormones concentrations. The RESTR treatment induced a decrease in milk production (- 21 % compared with control treatment) and a modification of the metabolism of dairy ewes characterized by an increase in plasma non-esterified fatty acids (NEFA), which represents the balance between adipose tissue mobilization and the use of NEFA by other tissues (+ 153 %), cholesterol (+ 17 %) and β-hydroxybutyrate (+ 4 %) levels. As a result, a decrease in body weight of dairy ewes was observed (-7 %). Feed restriction also resulted in a decrease in milk lipolysis estimated by the milk FFA measured by the copper-soap method (- 63 % and - 62 %, respectively for morning and evening milking) or by the reference Bureau of Dairy Industry (BDI) method (- 51 % and – 57 %, respectively for morning and evening milking). The decrease in milk spontaneous lipolysis under feed restriction was not associated with a decrease in lipoprotein lipase activity in ewes. These results will be completed with proteomic and lipidomic studies in milk samples to better understand mechanisms initiated in the ewe species specifically with regard to lipolysis in milk.

Role of Adiponectin in the Androgen-Mediated Cardiometabolic Complications in a Rat Model of Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-age women and is associated with a high prevalence of obesity, adipose insulin resistance (adipose IR), and insulin resistance (IR). Adipose IR is an early metabolic defect in the development of whole-body IR. Specific evaluation of adipose IR and its consequences on the whole-body metabolic state in women with PCOS has not been thoroughly investigated. Adiponectin is a peptide secreted by adipocytes that increases insulin sensitivity. PEG-BHD1028 is a novel potent peptide adiponectin receptor agonist. Despite that PEG-BHD1028 modulates insulin sensitivity in different models of diabetes, the potential of PEG-BHD1028 to attenuate androgen-mediated adipose IR and obesity remains unknown. Hypothesis: We tested the hypothesis that PEG-BHD1028 attenuates adipose IR and obesity in a rat model of PCOS. Methods: To induce PCOS, four-week-old female Sprague Dawley rats were implanted with dihydrotestosterone (DHT) silastic tubes (7.5 mg) or placebo (PBO) for 90 days (n=4-8/group). During the final three weeks of DHT treatment, rats received PEG-BHD1028 (25 μg/kg/day) subcutaneously. Body weight (BW) by gravimetry, fat and lean mass were measured by Echo-MRI. Fasting plasma insulin was measured by ELISA. Fasting plasma glucose and non-esterified fatty acids (NEFA) were measured with a clinical chemistry analyzer. HOMA-IR, an index of systemic IR, and adipose IR (fasting insulin x fasting NEFA) were calculated. Protein levels of insulin signaling markers including IRS1, p-IRS1 (Ser1101), PI3 kinase p110, Akt, p-Akt (SER473), GLUT4, mTOR, p-mTOR (Ser2481) were quantified in the retroperitoneal fat by Western-blot. Results: DHT significantly (p<0.05) increased BW (352.67± 6.93 vs 250.88 ± 5.26 g), fat mass (20.82 ± 1.48 vs 9.44 ± 1.81 g), and lean mass (316.92 ± 4.15 vs 224.45 ± 4.79 g), compared to PBO group. DHT significantly (p<0.05) increased HOMA-IR and adipose IR by 75% and 80%, respectively, compared to PBO group. DHT downregulated retroperitoneal fat p-IRS-1, IRS-1, p-mTOR, mTOR, GLUT4, PI3 kinase and Akt protein expression by 50% to 70% while upregulating p-Akt by 1.8- fold compared to the PBO group. PEG-BHD1028 significantly decreased BW, fat mass and lean mass while attenuating IR by 34.7% reduction in HOMA-IR and significantly (p<0.05) decreased adipose IR by 51.6% in PCOS rats. Interestingly, PEG-BHD1028 significantly (p<0.05) upregulated p-IRS-1, IRS-1, p-mTOR, mTOR and p-AKT levels by 2.6-, 3-, 2.2-, 4-, 2.6- fold, respectively with no impact on the other insulin signaling markers compared to vehicle-treated group. Conclusion: PCOS rats exhibit obesity and lower adiponectin levels that are associated with both adipose and whole-body insulin resistance. Activating adiponectin receptors with PEG-BHD1028 attenuated PCOS-associated obesity and adipose IR. Significance: Targeting adiponectin signaling could be a novel and effective therapeutic approach to mitigate metabolic dysfunction in females with excess androgens. Supported by NIH-NIGMS grant P20GM121334 (L.L.Y.C. and D.G.R.), NIH-NIGMS grant P20GM121334, P20GM104357, NIH-NHLBI grant P01HL51971, NIH-NIMHD-P50MD017338 and University of Mississippi Medical Center Medical Student Research Program (R.C.) and the Robert M. Hearin Foundation (R.C.). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Responses of selected plasma metabolites to a two-day nutritional challenge of goats divergently selected for functional longevity

Understanding the extent to which genetics × environment plays a role in shaping individual strategies to environmental challenges is of considerable interest for future selection of more resilient animals. Accordingly, the objective of this study was to evaluate the metabolic responses to a nutritional challenge of goats divergently selected for functional longevity based on plasma metabolites and the repeatability of these responses across 2 experimental farms and years. We carried out 6 different experimental trials from years 2018 to 2022 (4 trials on site Bourges (2018-21) and 2 trials (2021-22) on site Grignon) in which 267 first kidding goats, daughters of Alpine bucks divergently selected for functional longevity, longevity plus (n = 137), and longevity minus (n = 130), were exposed to a 2-d nutritional challenge in early lactation. The experiments consisted of a 5 or 7-d control period (pre-challenge) on a standard lactation diet followed by a 2-d nutritional challenge with straw-only feeding and then a 7 or 10-d recovery period on a standard lactation diet, for site Bourges and Grignon, respectively. During the challenge plasma metabolite composition was recorded daily. Linear mixed-effects models were used to analyze all traits, considering the individual as a random effect and the 2x2 treatments (i.e., genetic line and year nested in site) and litter size as fixed effects. The linear mixed-effects model using a piecewise arrangement was used to analyze the response/recovery profiles to the nutritional challenge. Random parameters estimated for each individual, using the mixed-effects models without the fixed effects of genetic line, were used in a Sparse Partial Least Square Discriminant Analysis (sPLS-DA) to compare the goat metabolism response to the challenge on a multivariate scale. The plasma metabolites, glucose, β-hydroxybutyrate (BHB), and nonesterified fatty acids (NEFA), and urea concentrations responded to the 2-d nutritional challenge. Selection for functional longevity did not affect plasma glucose, NEFA, BHB, and urea response/recoveries to a 2-d nutritional challenge. However, site, trial, and litter size affected these responses. Moreover, the plasma metabolites seem not to fully recover to prechallenge levels after the recovery phase. The sPLS-DA analysis did not discriminate between the 2 longevity lines. We observed meaningful between-individuals' variability in plasma BHB, especially on the prechallenge and rate of response and rate of recovery from the 2-d nutritional challenge (CV = 26.2%, 36.1%, and 41.2%, repeatability = 0.749, 0.322, and 0.741, respectively). Plasma NEFA recovery from challenge also demonstrated high between-individuals' variability (CV = 16.4%, repeatability = 0.323). Selection for functional longevity did not affect plasma metabolites responses to a 2-d nutritional challenge in dairy goats. Plasma NEFA and BHB response/recovery presented high between-individuals' variability, indicating individual adaptative characteristics to nutritional challenges not related to the environmental conditions but to inherent individual characteristics.

Feed restriction of lactating cows triggers acute downregulation of mammary mTOR signaling and chronic reduction of mammary epithelial mass

While there is generally no consensus about how nutrients determine milk synthesis in the mammary gland, it is likely that the mechanistic target of rapamycin complex 1 (mTORC1) plays a role as a key integrator of nutritional and mitogenic signals that can influence a multitude of catabolic and anabolic pathways. The objectives of this study were to evaluate acute changes (<24 h) in translational signaling, in addition to chronic changes (14 d) in mammary gland structure and composition, in response to a severe feed restriction. Fourteen lactating Holstein dairy cows were assigned to either ad libitum feeding (n = 7), or a restricted feeding program (n = 7). Feed-restricted cows had feed removed after the evening milking on d 0. Mammary biopsies and blood samples were collected 16 h after feed removal, after which cows in the restricted group were fed 60% of their previously observed ad lib intake for the remainder of the study. On d 14, animals were sacrificed and mammary glands dissected. In response to feed removal, an acute increase in plasma nonesterified fatty acid concentration was observed, concurrent to a decrease in milk yield. In mammary tissue, we observed downregulation of the mTORC1-S6K1 signaling cascade, in addition to reductions in mRNA expression of markers of protein synthesis, endoplasmic reticulum biogenesis, and cell turnover (i.e., transcripts associated with apoptosis or cell proliferation). During the 14 d of restricted feeding, animals underwent homeorhetic adaptation to 40% lower nutrient intake, achieving a new setpoint of 14% reduced milk yield with 18% and 29% smaller mammary secretory tissue dry matter and crude protein masses, respectively. On d 14, no treatment differences were observed in markers of protein synthesis or mammary cell turnover evaluated using gene transcripts and immunohistochemical staining. These findings implicate mTORC1-S6K1 in the early phase of the adaptation of the mammary gland's capacity for milk synthesis in response to changes in nutrient supply. Additionally, changes in rates of mammary cell turnover may be transient in nature, returning to basal levels following brief alterations that have sustained effects.

Clusters of adipose tissue dysfunction in adults with type 2 diabetes identify those with worse lipidomic profile despite similar glycaemic control.

To investigate clusters of adipose tissue dysfunction, that is, with adipose tissue insulin resistance (ADIPO-IR) and large waist circumference (WC), identify a worse lipidomic profile characterised by a high proportion of lipids rich in saturated fatty acids (SFA). Hierarchical clustering based on WC and ADIPO-IR (calculated as fasting plasma non-esterified fatty acids times fasting plasma insulin, FFA×INS), was performed in 192 adults with overweight/obesity and type 2 diabetes (T2D) treated with metformin (HbA1c=7.8%). Free fatty acid composition and lipidomic profile were measured by mass spectrometry (GC-MS and LC-MSQTOF). Indexes of fatty acid desaturation (stearoyl-coA desaturase-1 activity, SCD116=palmitoleic acid/palmitic acid and SCD118=oleic acid/stearic acid) and of insulin resistance (HOMA-IR) were also calculated. Three clusters were identified: CL1 (ADIPO-IR=4.9±2.4 and WC=96±7cm, mean±SD), CL2 (ADIPO-IR=6.5±2.5 and WC=114±7cm), and CL3 (ADIPO-IR=15.0±4.7 and WC=107±8cm). Insulin concentrations, ADIPO-IR, and HOMA-IR significantly increased from CL1 to CL3 (all p<0.001), while fasting glucose concentrations, HbA1c, dietary lipids and caloric intake were similar. Moreover, CL3 showed significantly higher concentrations of monounsaturated free fatty acids, oleic and palmitoleic acids, triglycerides (TAG) rich in saturated FA and associated with de novo lipogenesis (i.e., TAG 46-50), higher SCD116, SCD118, ceramide (d18:0/18:0), and phosphatidylcholine aa(36:5) compared with CL1/CL2 (all p<0.005). High ADIPO-IR and large WC identify a worse lipid profile in T2D characterised by complex lipids rich in SFA, likely due to de novo synthesis given higher plasma monounsaturated FFA and increased desaturase activity indexes. ID NCT00700856 https://clinicaltrials.gov.

The value of neck adipose tissue as a predictor for metabolic risk in health and type 2 diabetes

Upper-body adiposity is adversely associated with metabolic health whereas the opposite is observed for the lower-body. The neck is a unique upper-body fat depot in adult humans, housing thermogenic brown adipose tissue (BAT), which is increasingly recognised to influence whole-body metabolic health. Loss of BAT, concurrent with replacement by white adipose tissue (WAT), may contribute to metabolic disease, and specific accumulation of neck fat is seen in certain conditions accompanied by adverse metabolic consequences. Yet, few studies have investigated the relationships between neck fat mass (NFM) and cardiometabolic risk, and the influence of sex and metabolic status. Typically, neck circumference (NC) is used as a proxy for neck fat, without considering other determinants of NC, including variability in neck lean mass. In this study we develop and validate novel methods to quantify NFM using dual x-ray absorptiometry (DEXA) imaging, and subsequently investigate the associations of NFM with metabolic biomarkers across approximately 7000 subjects from the Oxford BioBank. NFM correlated with systemic insulin resistance (Homeostatic Model Assessment for Insulin Resistance; HOMA-IR), low-grade inflammation (plasma high-sensitivity C-Reactive Protein; hsCRP), and metabolic markers of adipose tissue function (plasma triglycerides and non-esterified fatty acids; NEFA). NFM was higher in men than women, higher in type 2 diabetes mellitus compared with non-diabetes, after adjustment for total body fat, and also associated with overall cardiovascular disease risk (calculated QRISK3 score). This study describes the development of methods for accurate determination of NFM at scale and suggests a specific relationship between NFM and adverse metabolic health.

Fat supplement for dairy cows during early lactation – potentials, challenges, and risks – a meta-analysis

ABSTRACT The most critical challenge in early lactation is to meet the increasing energy demand for milk production, which results in a negative energy balance (EB). The objective of this study was to evaluate the productive performance and plasma metabolite responses of early lactating dairy cows fed diets supplemented with increasing levels of different fat sources. Diets were categorized as diets supplemented with saturated fatty acid rich fat sources (SFAR), with Ca-soaps of fatty acids (CaFA), and with polyunsaturated fatty acid rich fat sources (PUFAR). There was an interaction between crude fat level and source for dry matter intake (DMI); each percentage-unit increase reduced DMI by 0.38 and 0.77 kg/d in CaFA and PUFAR, respectively, and increased DMI by 0.55 kg/d in SFAR. Corrected milk yield increased by 0.44 kg/d for each percentage-unit increase in crude fat level. Plasma non-esterified fatty acid (NEFA) concentration increased with 0.04 mmol/L per percentage-unit increase. In conclusion, the increased crude fat level increased corrected milk yield. Fat supplementation in early lactation does not seem to cause negative effects on productive performance or metabolism, and despite a small increase, both plasma NEFA and β-hydroxybutyrate (BHB) concentrations stayed below the threshold for incidence of subclinical ketosis.

85 Evaluation of a Saccharomyces cerevisiae fermentation product on performance, plasma metabolites, rumen parameters, and fecal pathogen shedding in feedlot steers

Abstract The objective of the experiment was to evaluate a commercial Saccharomyces cerevisiae fermentation product (SCFP; NaturSafe, Dimond V, Cedar Rapids, IA) on performance, plasma metabolites, rumen parameters, and fecal pathogen shedding in feedlot steers. Crossbred steers (n = 61; 271 ± 48.1 kg) were sourced from 3 different research units at Oklahoma State University and assigned to 1 of 3 experimental treatments in a randomized complete block design. Steers were group housed in pens equipped with an automated individual feed intake system. Treatments consisted of a negative control (CON), CON with tylosin phosphate (TYL; 9.9 mg · kg-1 of diet DM), or CON with SCFP (1.63 g · kg-1 of diet DM). Body weight and feed efficiency did not differ among treatments (P ≥ 0.12). However, steers fed SCFP tended to have greater ADG from d 35 to 56 (P = 0.10). In addition, steers fed SCFP exhibited increased DMI from d 56 to 112 (P = 0.03), a tendency for increased DMI from d 112 to final (P = 0.07), and increased DMI overall (P = 0.05). There was no treatment × time interaction for pH, pH change, or lactate concentrations in rumen fluid (P ≥ 0.11), but all were impacted by time (P &amp;lt; 0.01). A treatment × time interaction (P &amp;lt; 0.01) was detected for fecal pH and fecal pH change, with the pH being greater in TYL fed steers on d 56 and in CON fed steers on the final day. Steers that consumed CON had a reduced fecal pH (P &amp;lt; 0.01) and steers consuming SCFP tended to have a reduced fecal pH (P = 0.08) from d 35 to 56 compared with TYL fed steers, while both CON and SCFP fed steers experienced an increase in fecal pH from d 56 to 112 (P &amp;lt; 0.01). A time effect was detected (P ≤ 0.04) for plasma glucose, lactate, urea nitrogen, and non-esterified fatty acid concentrations among treatment groups. A treatment × time interaction was observed (P &amp;lt; 0.02) for stx2 genes of Shiga toxin producing Escherichia coli (STEC) in individual fecal samples where SCFP and TYL fed steers tended to exhibit an increased concentration compared with CON fed steers on d 14, while on d 190 CON and SCFP fed steers exhibited an increased concentration compared with TYL fed steers. Overall, STEC, E. coli O157:H7, and Salmonella concentrations were all impacted by time (P &amp;lt; 0.001). This experiment suggests that SCFP could be utilized as a potential alternative to TYL in feedlot cattle without adversely affecting cattle performance. However, SCFP did not impact pathogen shedding. In addition, CON fed steers performed similarly to both SCFP and TYL fed steers.

The Effect of Supplementing White Sweet Lupine Grain Meal (Lupinus albus L.) on Blood and Milk Metabolites, Milk Yield, and Quality of Dairy Cows in Ethiopia

Feed is the cornerstone of dairy production, serving as a crucial input for sustainable milk production. This trial aimed to investigate the effect of white sweet lupine grain meal inclusion on feed intake, blood and milk metabolites, milk yield, and quality. The experimental cows had a parity of 2±0.71 (mean ± SD), a daily milk yield of 12.72 ± 0.9, and an average body weight of 412.6 ± 21.5 kg. The varying proportions of treatment diets were: 75, 50, 25 and 0% (T1, T2, T3 and T4) treatment groups respectively. Data collected during the study were subjected to analysis of variance to determine significant differences. Cows fed diet T1 showed a better dry matter (10.39 kg/day), organic matter (7.31 kg/day), nitrogen (2.42 kg/day), and NDF intakes (3.75 kg/day) that had significant difference on (p&lt;0.05). When lupine inclusions dropped from 75 to 50 and even to 25%, the N digestibility decreased from 76.63, 70.66, and 65.6%, respectively, and the digestibility of N in all treatment diets significantly decreased (p &lt; 0.01). Once more, cows fed T1 diet had the highest (p&lt;0.01) plasma glucose concentration (116.81 mg/dl) among the four experimental groups. Cows fed T2 and T4 diets showed significant variation at (p&lt;0.05) in plasma glucose levels, with values of 108.7 and 110.16 mg/dl, respectively. Cows fed T1 had relatively lower plasma beta-Hydroxybutyric acid and non-esterified fatty acid concentrations (p&lt;0.05) than others, with mean values of 3.23 and 1.28 mg/dl respectively. The partial inclusion of white sweet lupine grain meal up to the level of 75% is highly suggested as a better alternative feed source.

Bile acids metabolism in the gut-liver axis mediates liver injury during lactation

AimsThe obesity epidemic, especially in pregnant women, linked to a higher risk of liver diseases. Bile acids (BAs) are known to participate in liver metabolism, but this function during obesogenic reproductive process remains largely uncertain. The study aims to identify whether a high-fat diet (HFD) during pregnancy negatively disturbs liver metabolism and the potential role of BAs and gut microbiota (GM)in a sow model. Main methodsReproductive (RP) or non-reproductive (NRP) sows were fed a 15 % HFD containing compound oil. Body condition, blood parameters, and BAs levels/profile during gestation and lactation were monitored. The tissues and colonic GM were collected after euthanasia at the end of lactation. HepG2 hepatocytes were used to test the effects of BAs on liver damage and the mechanism. Key findingsReproductive sows fed an HFD (HF-RP) experienced increased weight loss, and elevated plasma non-esterified fatty acid (NEFA) during lactation, consistent with exacerbated lipolysis, aggravating the risk of liver damage. HF-RP sows exhibited an enlarged BAs pool size and alterations in composition (higher levels of CDCA and LCA species) along with a drastic change in the GM (increased Firmicutes/Bacteroidetes ratio and declined Lactobacillus abundance). Furthermore, the liver FXR-SHP pathway, BAs synthesis and transport underwent adaptive regulation to sustain the BAs homeostasis and hepatic lipid metabolism. CDCA alleviated endoplasmic reticulum (ER) stress induced by palmitic acid via FXR pathway, in HepG2 cells. SignificanceLactation BAs metabolism signal in gut-liver axis coordinated the risk of liver damage induced by exacerbated lipolysis in obesogenic pregnancy.

Short-term responses of meat ewes facing an acute nutritional challenge in early-mid lactation.

Simulating a consequence of a climate change event on feed availability, responses of Mediterranean meat ewes facing an acute undernutritional challenge (CHA; i.e., fed only low nutritional value cereal straw) were evaluated at a sensitive physiological stage (i.e., early suckling). Forty Romane ewes were chosen at early-mid pregnancy (around 2 mo) according to parity (20 primiparous, PRIM; 20 multiparous, MULT); feed efficiency genetic line of their sires (residual feed intake [RFI]; efficient, RFI-, n = 10 per parity; inefficient, RFI+, n = 10 per parity); litter size (i.e., bearing twins, diagnosed by ultrasonography); body weight (BW, kg) and body condition score (BCS) (initial BW and BCS [mean ± SD]: 51.6 ± 7.41kg; 2.5 ± 0.20, respectively; representing flock' averages per parity). Effects on dry matter intake (DMI), ewes' BW and BCS, subcutaneous dorsal fat thickness (DFT), energy metabolism (plasma non-esterified fatty acids [NEFA], β-hydroxybutyrate (β-OHB), glucose, urea, triiodothyronine [T3]), and lambs' growth (BW and average daily gain [ADG]; g/d) were examined before, during and after CHA. Individuals' profiles of the response-recovery to CHA were described using a piecewise mixed-effects model. The fixed effect of parity and genetic line and the random effect of individual (ewe) were considered. A linear mixed-effects model was fitted to explore the effects on lambs' growth. The 2-d straw-only CHA had significant effects on most of the recorded parameters. Meaningful drops and recoveries were observed on ewes' DMI, BW, and DFT with effect on postchallenge levels. BW, BCS, DFT, or DMI were also affected by parity (MULT > PRIM) but not by genetic line. Plasma NEFA, β-OHB, glucose, urea, and T3 responded well to CHA with drops in T3, urea, and glucose levels, whereas NEFA and β-OHB significantly increased after CHA. MULT ewes presented sharper β-OHB recovery from CHA than PRIM (P ≤ 0.05). With this study, we provide tangible and necessary data for an emerging field of research. Our results give new insights into how such a short and abrupt CHA affects some key zootechnical and physiological parameters, and to what extent the impacts of CHA and the ewes' response-recovery are influenced. It also revealed potential between-individual differences in the adaptive capacities of ewes, which require further exploration.

Towards sustainable aquaculture: Assessing polychaete meal (Alitta virens) as an effective fishmeal alternative in European seabass (Dicentrarchus labrax) diets

In recent years, the pursuit of sustainable aquaculture practices has focused on alternatives to fisheries-derived ingredients, to avoid economic and environmental unsustainability. Low-trophic organisms, such as polychaetes, could be a suitable alternative to fishmeal due to their high protein content. This study aimed to investigate the feasibility of replacing fishmeal with the polychaete meal (Alitta virens; PM) in diets for European seabass (Dicentrarchus labrax; Wi, ∼14.5 g). Four isoproteic (51% dry matter, DM) and isolipidic (17% DM) diets were fed to seabass juveniles: a fishmeal-based diet (FM) and three experimental diets with PM at inclusion levels of 2.5% (PM2.5), 5% (PM5), and 10% (PM10), replacing 10%, 20% and 40% of fishmeal, respectively. After 93 days of feeding, the effects of the PM on growth, digestibility, nutrient utilization, plasma metabolites, liver lipogenic activity, and anterior intestine histomorphology were analyzed. The environmental impact of all diets was also assessed. All diets were well-accepted by the fish, and promoted equal growth performance, ensuring high feed efficiency. The muscle EPA + DHA content in all dietary groups exceeded the recommended levels for human consumption. Hepatic lipogenesis and plasma triglyceride and non-esterified fatty acids (NEFA) levels were increased in fish fed PM2.5, suggesting that the PM promoted alterations in lipid metabolism, especially at low inclusion levels. PM2.5 also seemed to enhance the absorption capacity of the anterior intestine by increasing villus length and goblet cells number/area, albeit without impacting nutrient digestibility and growth performance. Furthermore, copper digestibility increased with higher levels of PM inclusion. The assessment of environmental sustainability indicated that the experimental diets incorporating PM present a more sustainable option compared to fishmeal. Overall, this study demonstrated that PM can serve as a sustainable alternative to fishmeal, replacing it by up to 40%, without compromising European seabass growth and nutrient utilization, while guaranteeing a high nutritional quality fillet for human consumption. The best environmental performance could be achieved with a diet comprising 5% to 10% (w/w) PM content. However, further research is needed to understand the underlying mechanisms of PM's effects on intermediary metabolism and its potential as a functional ingredient.

Chromium propionate in turkeys: effects on insulin sensitivity

The objective of this study was to evaluate the effects of dietary chromium (Cr), as Cr propionate (Cr Prop), on measures of insulin sensitivity in turkeys. Plasma glucose and nonesterified fatty acid (NEFA), and liver glycogen concentrations were used as indicators of insulin sensitivity. One-day-old Nicholas Large White female poults (n=336) were randomly assigned to dietary treatments consisting of 0 (control), 0.2, 0.4, or 0.6 mg supplemental Cr/kg diet. Each treatment consisted of 12 replicate cages with 7 turkeys per cage. Final BW were taken on d 34, and on d 35 two birds from each cage were sampled for plasma glucose and NEFA, and liver glycogen determination at the initiation (fed state) and termination (fasted state) of a 24-h fast. Following a 24-h fast, 2 turkeys per cage were refed (refed state) their treatment diet for 4 h, and then harvested. Feed/gain and ADG did not differ between control and Cr-supplemented turkeys over the 34-d study, but feed intake tended (P=0.071) to be greater for controls than turkeys receiving 0.4 mg Cr/kg diet. Fed turkeys had greater plasma glucose (P=0.002) and liver glycogen (P=0.001) concentrations, and lower (P=0.001) NEFA concentrations than fasted birds. Turkeys refed after fasting had greater (P=0.001) plasma glucose and liver glycogen concentrations, and lower (P=0.001) plasma NEFA levels than fed turkeys. Liver glycogen and plasma NEFA concentrations did not differ among control and Cr-supplemented birds in the fed, fasted, or refed state. Plasma glucose concentrations were not affected by treatment in fed or fasted turkeys. Turkeys supplemented with 0.2 or 0.4 mg Cr/kg and refed after fasting had lower (quadratic, P=0.038) plasma glucose concentrations than controls. Plasma glucose concentrations in refed birds did not differ among Cr-supplemented turkeys. The lower plasma glucose concentration in Cr-supplemented turkeys following refeeding is consistent with Cr enhancing insulin sensitivity.

Cold Exposure Regulates Hepatic Glycogen and Lipid Metabolism in Newborn Goats.

Cold exposure influences liver metabolism, thereby affecting energy homeostasis. However, the gene regulatory network of the liver after cold exposure remains poorly understood. In this study, we found that 24 h cold exposure (COLD, 6 °C) increased plasma glucose (GLU) levels, while reducing plasma non-esterified fatty acid (NEFA) and triglyceride (TG) levels compared to the room temperature (RT, 25 °C) group. Cold exposure increased hepatic glycogen content and decreased hepatic lipid content in the livers of newborn goats. We conducted RNA-seq analysis on the livers of newborn goats in both the RT and cold exposure groups. A total of 1600 genes were identified as differentially expressed genes (DEGs), of which 555 genes were up-regulated and 1045 genes were down-regulated in the cold exposure group compared with the RT group. Cold exposure increased the expression of genes involved in glycolysis, glycogen synthesis, and fatty acid degradation pathways. These results can provide a reference for hepatic lipid and glycogen metabolism in newborn goats after cold exposure.

Short communication: Predicting blood plasma non-esterified fatty acid and beta-hydroxybutyrate concentrations from cow milk-addressing systematic issues in modelling.

Negative energy status in early lactation is linked to a variety of metabolic disorders, reduced fertility, and decreased milk production. To improve the energy status of cows by breeding and management, the identification of negative energy status is crucial. While biomarkers such as non-esterified fatty acid (NEFA) concentration and beta-hydroxybutyrate (BHB) in blood plasma could be used to identify a negative energy state, measuring them directly from blood is both invasive and expensive. In this work, we developed prediction equations for blood plasma NEFA and BHB levels based on mid-IR spectral measurements of milk. The models were fitted using partial least squares regression and evaluated using both cross-validation and independent-herd validation. A total of 3183 spectral records from 606 lactations originating from three different herds were utilised. R2 values of 0.53 (RMSE=0.206mmol/l, RMSE of cross-validation (RMSECV) 0.217mmol/l) for NEFA and 0.63 (RMSE=0.326mmol/l, RMSECV=0.353mmol/l) for BHB were obtained. Furthermore, relatively similar prediction accuracies were found for BHB (RMSE of prediction (RMSEP) 0.411mmol/l and 0.422mmol/l) and NEFA (RMSEP=0.186mmol/l and 0.221mmol/l) when model training was done using two herds and validated on the third herd. The results from the model fits confirm that it is possible to build blood plasma BHB and NEFA models based on mid-IR spectra that are sufficiently accurate for practical use.

Effects of OmniGen® PRO on ruminal fermentation, stress, and inflammation of Holstein cattle induced with a subacute ruminal acidosis

The aim of our study was to examine the effects of an immunomodulatory feed additive (OmniGen® PRO, Phibro Animal Health, Teaneck, NJ) on ruminal fermentation homeostasis and biomarkers of stress and inflammation in dairy heifers following subacute ruminal acidosis (SARA). Holstein heifers (n = 32, 8.4 ± 0.3 months old) were allocated to receive two treatments based on body weight (BW). Treatments were (1) control (CON; n = 16, no additive) and (2) OmniGen® PRO (OGPRO, n = 16, 10 g/100 kg BW, top-dressed). From d 1 to 69, and d 72 to 77, heifers were fed ad libitum a basal TMR formulated for early lactation. On d 70, the TMR offerings were reduced by 50% based on the intake of the previous 3 days. On d 71, heifers were fed ad libitum a starch challenge diet, which was a 50/50 mix steam-rolled barley and the basal TMR on a DM basis, to induce SARA. Rumen fluid and blood samples were collected on d 66, 71, and 73. Prior to the challenge, DMI, ADG, and feed efficiency were not affected by treatment. Following the challenge, all heifers experienced a 43% decline in DMI. Rumen pH was lower on the challenge day than pre and post challenge but was unaffected by treatment. Ruminal lactate was negligible pre and post challenge but increased on the challenge day; OGPRO reduced ruminal lactate compared to CON. At all sampling points, rumen total VFA were higher in OGPRO than in CON. The challenge caused fluctuations in the acetate to propionate ratio in CON, while OGPRO heifers had less variation. Two days post challenge, OGPRO heifers tended to have lower plasma cortisol, haptoglobin, and non-esterified fatty acids (NEFA) than CON heifers. The OGPRO heifers maintained the mean corpuscular hemoglobin concentration (MCHC) and platelet concentration after the challenge, while their levels declined in CON. In this study, supplementing OGPRO to heifers fed an early lactation diet improved rumen fermentation measures prior to the starch challenge and reduced the negative effects of the challenge on rumen fermentation. In addition, following the challenge, indicators of systemic inflammation tended to be lower in heifers supplemented with OGPRO.

Effects of dietary rumen-protected choline supplementation to periparturient dairy cattle on inflammation, metabolism, and performance during an intramammary lipopolysaccharide challenge

Recent studies have suggested that dietary rumen-protected choline (RPC) supplementation can modulate immune function, attenuate inflammation, and improve performance in periparturient dairy cattle; however, this has yet to be evaluated during a mastitis challenge. Therefore, the objective of this study was to examine the effects of supplementation and dose of RPC on metabolism, inflammation, and performance during an intramammary lipopolysaccharide (LPS) challenge. Parous Holstein cows (parity, mean ± SD, 1.9 ± 1.1 at enrollment) were blocked by calving month and randomly assigned within block to receive either 45 g/d of RPC (20.4 g/d of choline ions; CHOL45, n = 18), 30 g/d of RPC (13.6 g/d of choline ions; CHOL30, n = 21), or no RPC (CON, n = 19) as a top-dress starting 24 d before expected calving until 21 d postpartum. Cows were alternately assigned within treatment group to either receive an intramammary LPS challenge (200 μg in each rear quarter; Escherichia coli O111:B4) or not at 17 DIM. Before the challenge, CHOL45 and CHOL30 cows produced 3.4 and 3.8 (±1.2 SED) kg/d more milk than CON, respectively. Dietary RPC supplementation did not mitigate the milk loss associated with the intramammary LPS challenge; however, CHOL45 and CHOL30 cows produced 3.1 and 3.5 (±1.4 SED) kg/d more milk than CON, respectively in the carryover period (22 to 84 DIM). Dietary RPC supplementation enhanced plasma β-hydroxybutyrate (BHB) concentrations before the LPS challenge, and increased plasma nonesterified fatty acids (NEFA) and acetylcarnitine concentrations during the LPS challenge, potentially reflecting greater adipose tissue mobilization, fatty acid transport and oxidation. Aside from trimethylamine N-oxide and sarcosine, which were increased in CHOL45-LPS as compared with CON-LPS, most other choline metabolite concentrations in plasma were unaffected by treatment, likely because more choline was being secreted in milk. Plasma lactic acid concentrations were decreased in CHOL45-LPS and CHOL30-LPS as compared with CON-LPS, suggesting a reduction in glycolysis or an enhancement in the flux through the lactic acid cycle to support gluconeogenesis. Plasma concentrations of fumaric acid, a byproduct of AA catabolism and the urea cycle, were increased in both choline groups as compared with CON-LPS during the LPS challenge. Cows in the CHOL45 group had greater plasma antioxidant potential before the LPS challenge and reduced plasma methionine sulfoxide concentrations during the LPS challenge compared with CON-LPS, suggesting an improvement in oxidant status. Nevertheless, concentrations of inflammatory markers such as haptoglobin and tumor necrosis factor α (TNFα) were not affected by treatment. Taken together, our data suggest that the effects of dietary RPC supplementation on milk yield could be mediated through metabolic pathways and are unlikely to be related to the resolution of inflammation in periparturient dairy cattle. Lastly, dose responses to dietary RPC supplementation were not found for various economically important outcomes including milk yield, limiting the justification for feeding a greater dietary RPC dose in industry.

Resveratrol reverses Palmitic Acid-induced cow neutrophils apoptosis through shifting glucose metabolism into lipid metabolism via Cav-1/ CPT 1-mediated FAO enhancement

Elevated plasma nonesterified fatty acids (NEFAs) affect neutrophils function and longevity during the periparturient period in dairy cows. Previous research has shown that resveratrol (RSV) may protect cell viability from NEFA-induced damage by regulating energy metabolism. However, it is unclear whether RSV has a protective effect on palmitic acid (PA)-treated neutrophils. The aim of this study was to investigate the molecular regulatory mechanism of the protective effect of RSV on neutrophils. The results showed that treatment with high concentrations of RSV (50 μM, 100 μM) maintained neutrophils activity by inhibiting neutrophils apoptosis (P < 0.05). Further analysis showed that high concentrations of RSV enhanced fatty acid oxidation (FAO) to produce ATP by promoting the expression of CAV1, ACSL-1 and CPT1 (P < 0. 05) while inhibiting glycolysis by suppressing PFK1 activity (P < 0. 05) and reducing glucose transport-related protein (GLUT1/GLUT4) expression by inhibiting glucose uptake (P < 0.05). These results suggest that RSV protects neutrophils from PA-induced apoptosis by regulating energy metabolism. Our results revealed that RSV protects neutrophils from PA-induced apoptosis by shifting glucose metabolism to lipid metabolism. This study tenders to a meaningful understanding of the effects of RSV on neutrophils function in periparturient cows suffering from negative energy balance (NEB).

Effects of the timing of protein infusion on the daily rhythms of milk synthesis and plasma hormones and metabolites in dairy cows

Milk synthesis exhibits a daily rhythm that is modified by the timing of feed intake. However, it is unknown how specific nutrients entrain this daily rhythm. Amino acids have an important role in milk synthesis, and may have a role in entrainment of mammary circadian rhythms. The objective of this study was to determine the effects of intestinally absorbed protein on daily rhythms of milk and milk component synthesis and key plasma hormones and metabolites. Nine lactating Holstein cows were assigned to 1 of 3 treatment sequences in a 3 × 3 Latin square. Treatments included abomasal infusions of 500 g/d of sodium caseinate either continuously throughout the day (CON), for 8 h/d from 0900 to 1700 h (DAY), or for 8 h/d from 2100 to 0500 h (NGT). Cows were milked every 6 h during the final 8 d of each period. A 24-h rhythm was fit to data using cosine analysis and the amplitude and acrophase were determined. Night infusion of protein decreased the daily milk yield and milk protein yield by 8.2% and 9.2%, respectively. Milk fat yield was increased 5.5% by DAY and milk fat concentration was increased 8.8% by NGT. Milk yield exhibited a daily rhythm in all treatments, with NGT increasing the amplitude of the daily rhythm 33% compared with CON. Milk fat concentration fit a daily rhythm in CON and NGT, but not DAY, whereas milk protein concentration fit a daily rhythm in CON and DAY, but not NGT. Moreover, DAY abolished the daily rhythm of plasma glucose concentration, but induced rhythms of plasma insulin and nonesterified fatty acid concentrations. Results suggest that feeding increased protein levels during the early part of the day may increase milk fat yield and modify energy metabolism through increased daily variation in insulin-stimulated lipid release, but additional research focused on feeding multiple diets across the day is required.