Canine obesity is a complex metabolic disorder driven by luminal dysbiosis, impaired gut barrier function, and metaflammation. Following PRISMA 2020 guidelines, this systematic review evaluated the efficacy of pro-, pre-, and postbiotics in modulating the gut-adipose tissue axis in overweight dogs (BCS ≥ 6/9) or diet-induced obesity models. Searches across PubMed and Dimensions (April 2026) identified seven eligible experimental trials. Results suggest that postbiotic Bifidobacterium animalis subsp. lactis CECT 8145 reduced postprandial glucose AUC by 6 % strictly during energy restriction. Pasteurized Akkermansia muciniphila postbiotics limited diet-induced weight gain, though glucoregulatory impacts were highly strain-specific (AKK2 reduced fasting glucose and insulin resistance indexes, whereas EB-AMDK19 exerted no significant effect). Specific probiotics (including Enterococcus faecium, Bifidobacterium lactis, Lactiplantibacillus plantarum and Bifidobacterium breve) attenuated fasting hyperinsulinemia and preserved circulating adiponectin, but lipid profile improvements (triglycerides and total cholesterol) were inconsistent across trials. In dogs, increased luminal short-chain fatty acids are not consistently mirrored by endocrine responses, so the coupling between microbial metabolites and incretin signaling remains incomplete. A critical lack of standardized reporting for species-validated insulin sensitivity metrics was identified. In conclusion, microbiome-targeted therapies, particularly inanimate postbiotics, may represent useful adjunctive strategies to mitigate metabolic dysregulation in obesogenic environments. However, clinical efficacy remains strictly strain-specific and dependent on host energy balance. Given the scarcity of high-certainty evidence, future trials must integrate dynamic physiological assessments with species-validated surrogate indexes alongside standardized dietary controls.
Metabolism of serotonin (5-HT) by gut microorganisms has been demonstrated in several species. However, information regarding 5-HT metabolism by rumen microbiota remains limited. The objective of this study was to evaluate ruminal metabolism of 5-HT-related metabolites and subsequent changes in circulating concentrations in bovines following oral administration of 5-Hydroxytryptophan (5-HTP). In vitro incubation of rumen fluid with 5-HTP (100 µM), 5-HT (100 µM), or 5-Hydroxyindoleacetic acid (5-HIAA; 100 µM) were assessed to evaluate the degradation and metabolization of these compounds. In an in vivo experiment, cows received oral administration of 5-HTP at doses of 0 or 10 mg/kg of body weight. Ruminal fluid and blood samples were collected at multiple time points following 5-HTP administration. In vitro incubation of 5-HTP rapidly disappeared resulting in a significant reduction after 60 min and complete disappearance by 480 min, without a corresponding increase in 5-HT concentrations; however, 5-HIAA concentrations increased. The incubation of 5-HT in rumen fluid caused a slight and transient increase in 5-HIAA concentrations. Oral administration of 5-HTP increased the area under the curve (AUC) for ruminal concentrations of tryptophan, 5-HTP, 5-HT, and 5-HIAA. The intake of 5-HTP increased ruminal concentration of 5-HT and 5-HIAA. Additionally, the AUC of serum 5-HT and 5-HIAA concentrations increased. Rumen microorganisms rapidly metabolize free 5-HTP, resulting in low efficiency of 5-HT production; however, this process still makes a significant contribution to circulating 5-HT concentrations in the host.
In sheep production, bacterial infections often cause embryo implantation failure and early pregnancy loss, resulting in substantial economic losses. These detrimental effects are closely associated with bacterial lipopolysaccharide (LPS)-induced disruption of uterine function, mediated via inflammation and oxidative stress. Although nitric oxide synthase 1 (NOS1) has been established to play a regulatory role in the induction of oxidative stress, its precise role during the peri-implantation period in sheep remains unclear. In this study, pregnant ewes during three critical periods of embryo implantation in sheep (days 12, 16, and 20) were intrauterinely perfused with LPS (50 μg/ewe) or PBS via laparoscopy and endometrial tissues were collected at the maternal-fetal interface at 24 h post-perfusion to evaluate dynamic changes in receptivity and redox status. A two-way ANOVA revealed that LPS had significant inhibitory effects on the expression of the implantation-related genes ITGB1 and ITGB5, while treatment-by-day interactions were detected for HOXA10, HOXA11, ITGB3, and RSAD2, indicating that LPS disrupts the dynamic transcriptional programming of implantation both gene- and stage-specifically. Furthermore, LPS significantly decreased superoxide dismutase (SOD) and catalase (CAT) activities, increased malondialdehyde (MDA) levels, and upregulated NOS1 expression in vivo. To clarify the role of NOS1, we performed siRNA-mediated knockdown in a sheep endometrial epithelial cell line primed to a receptive state sequentially with progesterone, 17β-estradiol, and recombinant ovine interferon-tau. RNA-seq of NOS1-knockdown cells revealed significant enrichment of oxidative stress pathways, particularly glutathione metabolism. Functionally, NOS1 knockdown attenuated LPS-induced reactive oxygen species (ROS) accumulation, restored SOD and CAT activities, alleviated MDA damage, and partially rescued the expression of key implantation-related genes. Collectively, our findings revealed that LPS impairs endometrial receptivity by inducing oxidative stress and upregulating NOS1. Targeted inhibition of NOS1 in vitro effectively mitigates these deleterious effects, highlighting NOS1 as a critical mediator of LPS-associated implantation failure and a potential therapeutic target for improving reproductive efficiency in sheep.
Oxidative stress caused by production of reactive oxygen species (ROS) due to normal metabolism and/or external environment results in changes in follicular fluid microenvironment, oxidation of oocyte DNA (8‑hydroxy-2'deoxyguanosine levels; 8-OHdG) and poor-quality oocyte. Therefore, the present investigation was designed to evaluate the relationship between oocyte quality and intra-follicular environment (melatonin, 8-OHdG, 17β-estradiol and progesterone concentrations) in different sized follicles during summer and winter in water buffaloes. Slaughterhouse-derived ovaries were subjected for collection of follicular fluid from three (n = 42 each category in summer and winter) different categories of follicle based on diameter (Small: 8-9.9 mm; Medium: 10-11.9 mm; Large: 12-14 mm). Individual follicles were treated as independent observational units and analyzed using a factorial model including effects of season, follicular size, and their interaction. The results revealed higher (P < 0.05) melatonin and 17β-estradiol concentrations were associated with larger follicles and improved oocyte quality. Melatonin was positively associated (P < 0.05) with 17β-estradiol concentrations in different follicular categories during both seasons. Conversely, 8-OHdG followed an inverse association (P < 0.05) with melatonin in different categories of follicles during both seasons. Irrespective of follicles size, data revealed that good-quality oocytes (Grade A) were associated with higher melatonin concentrations, 102.11±3.88 pg/mL and 116.59±3.32 pg/mL in summer and winter, respectively. Ordinal logistic regression analysis identified melatonin concentration as the only significant independent predictor of oocyte quality (β=-0.226, OR=0.798; P < 0.001). Thus, it may be concluded that higher intra-follicular melatonin concentrations were associated with lower oxidative DNA damage and improved oocyte quality in water buffalo.
This study investigated the combined effects of light wavelength and photoperiod on adipokine responses, stress-related biomarkers, growth performance, and oxidative status in broilers. A total of 288 one-day-old male Ross 308 broilers were assigned to four treatment groups in a 2 × 2 factorial design based on light colour (white or green) and photoperiod pattern (continuous or intermittent) over a 42-day experiment. Body weight, feed intake, and feed conversion ratio (FCR) were recorded experimental period, and on day 42, serum biomarkers and oxidative stress markers in liver, heart, and kidney tissues were evaluated. Green light reduced serum visfatin and chemerin concentrations compared with white light (P < 0.05). Intermittent lighting reduced corticosterone and heat shock protein 70 concentrations but increased creatine kinase compared with continuous lighting (P < 0.05). Growth performance responses were mainly reflected in body weight and feed intake; FCR responses were limited to specific growth periods, with no significant effect on overall 0-42-day FCR. Among treatment combinations, intermittent-green lighting produced the highest final body weight and increased renal superoxide dismutase (SOD) activity and reduced glutathione (GSH) concentration relative to the other combinations. Overall, these findings indicate that light wavelength and photoperiod jointly influence metabolic, endocrine, and oxidative responses in broilers, and that intermittent green lighting may be considered a practical management approach for modulating selected growth-related and physiological responses under intensive rearing conditions.
Plasma concentrations of steroid hormones and pregnancy-related protein markers provide insight into critical reproductive processes in cattle. Handling and storage conditions are important to maintain the integrity of blood samples as the stability of biomolecules may be sensitive to environmental conditions, such as temperature or solar exposure. Blood was collected from pregnant Angus beef cows by jugular venipuncture into EDTA tubes to determine the impact of post-collection environmental conditions on plasma concentrations of progesterone (P4), prostaglandin F2α metabolite (PGFM), and pregnancy-associated glycoproteins (PAGs). Samples were randomly assigned to shade (28°C) or direct sunlight exposure (37°C) and incubated for 10, 30, or 60 min then cooled, or remained controls (ice-water bath only). Samples were transported to the lab on ice and plasma was isolated by centrifugation. Overall, plasma concentrations of P4 decayed (P < 0.0001) at 30 (15.2%) and 60 min (33.3%) in both environmental conditions compared to controls. Plasma concentrations of PGFM and PAGs were not affected (P > 0.8) by environmental exposure conditions or incubation duration. This study highlights the impact of time between blood collection and adequate cooling to reduce the potential degradation of key reproductive biomolecules in plasma.
Periparturient metabolic diseases remain a major challenge to the productivity, health, and welfare of small ruminants. Traditionally, disorders including pregnancy toxemia, early lactation ketotic disorders, hypocalcemia, and hypomagnesemia have been considered distinct disease entities arising primarily from nutritional deficiencies during late gestation and early lactation. However, increasing evidence suggests these conditions represent interconnected manifestations of disrupted physiological adaptation during the transition from pregnancy to lactation. During this period, maternal tissues must coordinate nutrient partitioning among maternal maintenance, fetal growth, placental function, colostrum production, and milk synthesis. Rapid fetal growth during late gestation, declining dry matter intake, and increasing mammary demand impose substantial energetic and mineral requirements that challenge metabolic homeostasis, particularly in prolific females carrying multiple fetuses. Failure of adaptive mechanisms regulating glucose metabolism, lipid mobilization, mineral homeostasis, oxidative balance, and endocrine signaling reduce capacity to adapt to increasing nutritional demands during gestation and lactation. This review integrates current understanding of metabolic adaptation during the periparturient period in small ruminants, with emphasis on interactions among nutrient partitioning, placental demand, fetal growth, and mammary function. Relationships among energy metabolism, mineral regulation, oxidative stress, inflammatory signaling, and endocrine adaptation in the context of maternal health, neonatal viability, and lactational performance are discussed highlighting the importance of coordinated maternal, placental, fetal, and mammary adaptation in regulating susceptibility to periparturient metabolic disease in small ruminants.
Brown adipose tissue (BAT) serves as a crucial thermogenic tissue in newborn goats, playing an important role in maintaining their core body temperature through adaptive thermogenesis. Initially, we found that nicotinamide (NAM) content was significantly higher in BAT (0.047 μg/g, n = 6 biological replicates) than that in white adipose tissue (WAT, 0.021 μg/g, n = 6 biological replicates). However, the effect of NAM on goat brown adipocytes remains unknown. The experimental results revealed that NAM enhanced lipid deposition, mitochondrial DNA content and the expression of uncoupling protein 1 (UCP1) in brown adipocytes. Here, 20 μM isoproterenol (ISO), a non-selective agonist for β-adrenergic receptors (β-ARs), was used to simulate cold exposure in brown adipocytes. We found that 2 mM NAM treatment significantly elevated lipid deposition and amplified thermogenesis of brown adipocytes under ISO-induced cold conditions. Furthermore, we found that NAM enhanced UCP1 promoter activity involving the EBF2 binding site, suggesting potential involvement of EBF2 in promoting UCP1 expression and thermogenesis in brown adipocytes. These findings offer new insights into nutritional strategies for enhancing BAT thermogenesis with NAM in goats.
Nutritional strategies to reduce oxidative stress (OS) and to improve female reproductive performance include supplementation with flavonoids such as quercetin (QUR), that may modulate OS and ovarian function depending on age and reproductive status. To evaluate whether QUR supports the onset of reproductive life or alleviates age-related OS, juvenile rabbit females (J; 8 weeks of age) and adult rabbit does previously subjected to repeated semi-intensive cycles (A; 12-13.5 months-old) received oral QUR supplementation (300 mg/kg, JQ and AQ) or remained untreated (JC and AC) for 8 weeks. Serum TNF-α and IL-1β (ELISA), antioxidant capacity (FRAP) and malondialdehyde (MDA) levels (TBARS) were monitored at the beginning, midpoint, and end of the experiment. At the endpoint, body composition was evaluated bioelectrical impedance analysis (BIA). Following in vivo ovulation induction, ovaries and blood samples were collected 14 h post-ovulation. Ovarian reserve was assessed by follicle counting, serum anti-Müllerian hormone (AMH) quantification (ELISA), and ovarian immunohistochemistry. Follicular apoptosis was evaluated by TUNEL assay, and steroidogenesis analysing serum oestradiol (E2), progesterone (P4) levels, and E2/P4 ratio (ELISA). QUR did not affect OS or inflammatory markers. MDA concentrations decreased over time in adults but remained unchanged in juveniles (p < 0.05) and antioxidant capacity increased during the first 4 weeks in adults and decreased in juveniles (p < 0.05). Age affected ovarian weight, P4 levels and P4/ E2 ratio (p < 0.05), with higher values in adults regardless of treatment. Follicular reserve declined with age (p < 0.05), although serum AMH levels and ovarian AMH immunoexpression were unchanged. In juveniles, QUR increased body energy content and serum P4 concentrations. No other ovarian parameters differed among groups or ages. In conclusion, under non-productive conditions, females showed no OS or inflammation compromising follicular reserve. QUR modulated energy reserves and luteal function in juveniles at the onset of reproductive life. Overall, oxidative status appears to be driven primarily by productive cycles rather than flavonoid supplementation.
The objective of this study was to determine the effects of winter environmental conditions and production systems on targeted mRNA expression profile of hair follicles (HF) in cattle, specifically focusing on genes regulating stress, inflammation, cellular integrity, and coat color. Two cattle breeds (Bos indicus, Brahman and Bos taurus, Angus) were subjected to two production systems without (NAT) or with a commonly used growth-promoting technology in commercial feedlots, TRT [100-200 mg of trenbolone acetate and 14-28 mg estradiol benzoate anabolic implants, in-feed monensin/tylosin (35/7 g/ton DM) and ractopamine hydrochloride (27 g/ton DM)] for a 180 day-period in Colorado State, USA (n = 50 steers/group). Growth performances were monitored and hair follicles were collected on a monthly basis from October 2023 to March 2024. Total RNA was extracted, reverse transcribed, and target genes were amplified by qPCR using 2^-ΔΔCt method. Angus cattle exhibited significantly higher ADG and FE from October through February compared to their Brahman counterparts, with the TRT production system further improving FE (P < 0.05) during November-December and January-February relative to the NAT system. A significantly higher gene expression of Cxcr2 and a lower expression of Asip were observed in the Angus breed compared to the Brahman counterparts. This breed-specific differential expression may reflect the differences in hair coat characteristics and physiological adaptive pathways. Compared to the NAT system, TRT treatment significantly upregulated the expression of Xcl1 and Asip while downregulating that of Cxcr2. These changes were consistent with the effects of anabolic steroids, antibiotics, and/or ractopamine. The expression of heat shock proteins (Hsp60, Hsp70, Hsp90), cytokines (IL6, IL18, Tnfα, Crp, IL10), chemokines and their related receptors (Xcl1, Cxcl12/14, Ccl2/4/5/20, Ccr2, Cxcr1/2), tight junction proteins (Cldn1, Ocln), and coat color-associated genes (Asip, Mc1r, Bmp2, Hoxc12, Lef1, Zhx3) followed seasonal patterns with peaks in October-November and/or December-February, which coincided with low temperatures. Collectively, to our knowledge, this is among the first studies showing a differential gene expression between breeds (Angus vs. Brahman), production systems (TRT vs. NAT), and season. By identifying hair follicle gene expression signatures associated with cold stress in beef cattle, this study provides a foundation for future mechanistic investigations.
The short-term buck-to-buck effect refers to the rapid stimulation of LH, testosterone, and sexual behavior in resting males after the introduction of a sexually active (SA) buck, but the long-term effects of such exposure remain unclear. This study investigated whether prolonged exposure to SA bucks stimulates endocrine activity and sexual behavior in recipient males. Recipient males were exposed either to two sexually inactive bucks undergoing sexual activation induced by a photoperiodic treatment (SA; n = 6) or to two sexually inactive (SI) bucks (n = 5). Testosterone concentrations were low and similar between groups before and during the first two weeks after exposure (P > 0.05). Thereafter, testosterone increased in recipient males exposed to SA bucks and remained higher than in those exposed to SI bucks from mid-February to mid-March (P < 0.05), before declining to comparable levels in both groups. By the end of April, testosterone concentrations were higher in males exposed to SI bucks (P < 0.05). At the time of introduction of the stimulus bucks, neither stimulus bucks nor the recipient males exhibited nudging behavior. Thereafter, from late February onward, recipient males exposed to SA bucks exhibited more frequent nudging behavior than those exposed to SI bucks (P < 0.05). These findings demonstrate that prolonged exposure to SA bucks progressively stimulates endocrine activity and socio-sexual behavior in recipient males, providing evidence for a long-term buck-to-buck effect. Notably, behavioral responses persisted even when testosterone declined, whereas delayed hormonal changes in SI-exposed males were not associated with behavioral activation.
Measuring T4 concentrations is an essential part of the diagnostic workup of dogs with suspected thyroid disease. While T3-determination provides valuable additional information in selected cases, the diagnostic benefit of rT3 still needs to be investigated. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) enables simultaneous quantification of TT4, TT3, and TrT3 with high precision and sensitivity, offering potential improvements in canine endocrinological assessments. The aims of this study were to develop and validate a LC-MS/MS method for the measurement of TT4, TT3, and TrT3 in canine serum, to establish reference intervals in clinically healthy dogs, and to compare the LC-MS/MS values with TT4 and TT3 results evaluated by routine chemiluminescence assays (CLIA). Leftover serum samples from 105 clinically healthy dogs, with unremarkable laboratory screenings, were analyzed by LC-MS/MS and reference intervals were determined according to the ASVCP guidelines: 11.44 - 46.38 nmol/l for TT4, 0.807 - 2.152 nmol/l for TT3 and 0.165 - 0.833 nmol/l for TrT3. Further, TT4 and TT3 values were compared to CLIA measurements with a bias of 0% for TT4 and +56% for TT3. Intra- and interassay-precision CVs (%) were below 4.00% and 9.80% for TT4, 4.73% and 6.60% for TT3 and 5.88% and 6.50% for TrT3, respectively. This study shows that the antibody-independent LC-MS/MS is a valid method to determine total canine T4, T3 and rT3 concentrations with high accuracy and provides a sound basis for future research in this species.
Ruminants experience major metabolic stress during the periparturient period, leading to negative energy balance (NEB), oxidative stress, and inflammation. While NEB is well studied in dairy cows, molecular responses to feed restriction in locally adapted fat-tailed sheep breeds remain unclear. This study aimed to study the effect of phased feed restriction and parturition on hepatic genes related to antioxidant defense, NADPH regeneration, and inflammation in Lori Bakhtiari and Turki Qashqai ewes. Twenty ewes were used in this study. The control group (Ctrl; n=10) received pre- and postpartum diets to meet 100% of the energy requirements. The Feed Restricted group (FR; n=10) received a diet to simulate a sudden energy deficit prepartum and postpartum. Liver biopsies were collected on week -3 and 3 relative to parturition. Pro-inflammatory cytokines (IL-6, IL-8, TNFα) were unaffected by FR or parturition. The hepatic mRNA expression of GCLM remained constant in the FR group but decreased in the Ctrl group postpartum. In addition, GCLM mRNA abundance was lower in the FR group compared to the Ctrl group prepartum, but higher postpartum. The hepatic mRNA expression of SRXN1 increased postpartum in the FR group but remained constant in Ctrl. In addition, SRXN1 showed higher abundance in the FR group than in the Ctrl group both prepartum and postpartum. Both hepatic mRNA expression of GPX3 and GPX4 were constant in the FR group but increased in the Ctrl group postpartum. Thus, no differences in GPX3 and GPX4 were detected between groups prepartum but were lower in the FR group compared to the Ctrl group postpartum. In addition, FR downregulated the hepatic mRNA expression of GCLC, G6PD, 6PGD, CAT, SOD1, and SOD3, while increasing GR1. Parturition decreased the hepatic mRNA expression GCLC, G6PD, 6PGD, and TXNRD1, and increased Hb, SOD1, and SOD3 mRNA abundance. Feed restriction reduced key hepatic antioxidant and NADPH-regenerating genes, while parturition further intensified oxidative processes. Despite these sudden changes in dietary energy prepartum and postpartum, inflammatory cytokines remained constant, indicating that fat-tailed ewes prioritize redox adaptation over inflammation under nutritional stress and parturition-related metabolic demands.
Feline hyperthyroidism is a prevalent endocrine disorder in geriatric cats, but studies regarding thyroid scintigraphic characteristics in South American populations are lacking. The aim of this study was to evaluate thyroid scintigraphic findings in cats with hyperthyroidism from Argentina. In this retrospective study, 536 hyperthyroid cats underwent 99mTc-pertechnetate thyroid scintigraphy, and the thyroid-to-salivary gland (T/S) ratio was determined. The median age of affected cats was 12 years (IQR 10-18 years). Bilateral asymmetric thyroid involvement was the most frequent scintigraphic presentation (38%), followed by bilateral symmetric (14.2%) and unilateral disease (31%) using size-based criteria. Multifocal uptake patterns were identified in 5.6% of cats, ectopic thyroid tissue in 11.2%, and scintigraphic features suggestive of thyroid carcinoma in 5.6%. The median T/S ratio was 2.8 (IQR 2.2-3.4) which exceeds the reference interval for clinically normal cats (<1.5). Cats exhibiting T/S ratios ≥2.1 demonstrated significantly higher serum total thyroxine (TT4) concentrations (8.1 μg/dl, IQR 6.8-10.2 μg/dl) than those with T/S ratios between 1.6 and 2 (5.3 μg/dl, IQR 4.9-6.2 μg/dl). A strong positive correlation was observed between T/S ratio and TT4 concentration (Spearman's ρ = 0.76, p < 0.001). These findings provide a comprehensive characterization of scintigraphic patterns in hyperthyroid cats from Argentina, constituting the largest cohort reported in the region to date. The comparatively high prevalence of ectopic thyroid tissue and suspected carcinoma highlights the relevance of scintigraphic assessment for diagnosis, staging, and therapeutic planning in cats with hyperthyroidism.
Maternal nutritional restriction during gestation impairs placental vascular development; however, the underlying mechanisms in goats are still not fully understood. This study investigated the effects of feed restriction (70 % of ad libitum intake) from day 50 of gestation until parturition on placental vascular morphometry and the expression of key angiogenic factors. Placentas from control goats (C, n = 5) and feed-restricted goats (PFR, n = 5) were analyzed using immunohistochemistry, histomorphometry, and RT-qPCR. Nutritional restriction significantly reduced the number of blood vessels while increasing their mean area and perimeter, without affecting vascular density. Immunohistochemistry revealed a marked reduction in FGF2 and ANGPT2 expression, accompanied by a compensatory increase in ANGPT1 and CD31. Transcriptional analysis showed an upward trend in the expression of genes such as KDR, while ANGPT1 expression was significantly increased. Overall, these findings indicate that maternal undernutrition induces adaptive vascular remodeling, characterized by fewer but larger vessels and selective modulation of angiogenic pathways, suggesting a compensatory mechanism aimed at preserving placental function under nutrient stress.
Sex steroids can modulate the daily pattern of behavior, body temperature, and metabolism in sheep. However, in young male sheep, chronic androgen exposure is required to trigger changes on these patterns. The aim of this study was to compare the daily behavioral (eating, ruminating, standing, lying, and sleeping), body temperature (eye and rectal), glucose and insulin concentrations, and sensitivity to insulin patterns in 5-6-month-old male lambs castrated shortly after birth and acutely or chronically treated with androgens. Thirty male lambs were treated with: 1) a single im dose of 100 mg of cyclopentyl testosterone propionate 48 h before the recordings (AcT; n = 10); 2) three weekly im doses as the one administrated to AcT with the last simultaneous to the administration to the AcT lambs (ChT; n = 10); 3) no hormonal treatment, remaining as controls (Con; n = 10). The treatments modified only the acrophase of eating (P = 0.02) and the glycemic robustness (P = 0.04), without altering other characteristics of the daily pattern of the variables evaluated. The ChT lambs showed an ∼ 1-h delay in the acrophase of the percentage of time spent eating compared with the AcT lambs (P = 0.01), as well as greater glycemic robustness than the Con lambs (P = 0.03). Acute androgen treatment was ineffective, whereas chronic treatment only had a slight impact on the daily patterns evaluated. The rigidity exhibited in all the other responses studied reinforces the conclusion that these patterns, which result from evolution favoring animal adaptation to the light-dark cycle, are highly conserved.
This study compared the in vitro stability of equine plasma adrenocorticotrophic hormone (ACTH) and serum insulin measured by chemiluminescent assay (CLA; Siemens Immulite 2000XPi) and immunofluorescent assay (IFA; Tosoh AIA-900) after storage at 4°C or room temperature (approximately 21°C) for clinically relevant periods. Fresh equine EDTA blood for ACTH and coagulated blood for insulin were aliquoted and analysed immediately (T0) and after storage. ACTH was assessed at 24, 48 and 72 hours; insulin was assessed at 24 hours, 72 hours and 7 days. Percentage recovery relative to T0 was analysed by repeated-measures ANOVA and confirmed by linear mixed-effects modelling. Agreement between assays at T0 was assessed using Bland-Altman analysis, with additional evaluation of normality of inter-assay differences, proportional bias and log-transformed ratio-based agreement. ACTH concentrations declined significantly over time at both temperatures with both assay methods. Under refrigeration, ACTH recovery was significantly greater with IFA than CLA at all time points, whereas no significant inter-assay difference was detected at room temperature. Bland-Altman analyses showed that baseline ACTH agreement varied with concentration magnitude, indicating proportional bias on the original scale; log-transformed analysis reduced this concern for refrigerated ACTH, although some residual concentration-dependent disagreement remained at room temperature. In contrast, insulin remained comparatively stable, with no meaningful assay-by-time interaction and no clear evidence of proportional bias on the original scale. These findings support prompt chilled handling of ACTH samples and suggest that, when immediate analysis is not possible, the IFA method provides results closer to the initial ACTH concentration than the CLA method, whereas insulin appears relatively robust to short-term storage conditions.
Chronic kidney disease (CKD) in dogs is a progressive disorder, often accompanied by metabolic and inflammatory alterations. Insulin resistance (IR) is well documented in humans with CKD; however, supporting evidence is lacking in dogs with CKD. The present study aimed to investigate the presence of IR in dogs with CKD, examine its association with renal function markers (creatinine and symmetric dimethylarginine [SDMA]) and pro-inflammatory cytokines, and assess differences according to CKD stage. This retrospective cross-sectional study included 66 client-owned dogs: 30 healthy controls and 36 dogs with CKD. Dogs with CKD were staged as 1-2 (n = 20) or 3-4 (n = 16) according to the International Renal Interest Society (IRIS) guidelines. Fasting blood samples were analyzed for serum glucose, insulin, creatinine, SDMA, interleukin (IL)-6, IL-8 (C-X-C motif chemokine ligand 8; CXCL8), IL-18, and tumor necrosis factor (TNF)-α levels. Indices of IR and β-cell function were calculated using the homeostasis model assessment (HOMA)-IR and HOMA-β. Dogs with CKD had significantly higher insulin and HOMA-IR values than healthy controls (P < 0.05), whereas no differences were observed for HOMA-β values. HOMA-IR values did not differ between CKD stages 1-2 and 3-4, and no correlation was found with creatinine or SDMA. In contrast, IL-6, IL-18, and TNF-α concentrations were significantly elevated (P < 0.05) and positively correlated with HOMA-IR in dogs with CKD. These findings suggest that IR in dogs with CKD might be associated with pro-inflammatory cytokines, although no association was observed between IR and CKD severity.
Horses with equine metabolic syndrome (EMS) are at an increased risk of laminitis following corticosteroid use. Ertugliflozin reduces hyperinsulinemia in horses with EMS, and thereforemay be a management option to reduce the insulin spike seen post corticosteroid use. It was hypothesised that oral ertugliflozin, administered before and after intra-articular (IA) triamcinolone acetonide (TA), will significantly lower the insulin response in comparison to placebo. A randomised, blinded, placebo-controlled, crossover design was performed on eight adult standardbred geldings with no history of laminitis. Once a day, horses were orally-administered with either 0.05 mg/kg of ertugliflozin or volume-matched placebo for four days before and four days after IA TA (18mg) was administered into a middle carpal joint. Horses then had a two-week washout period before the same process was repeated with the alternative treatment (ertugliflozin or placebo) and opposite carpal joint injected. During the eight-day treatment periods, blood was collected each day at 8 am and 12 pm for analysis of blood insulin, glucose and triglycerides concentrations. Using Bayesian modelling, the maximum plasma insulin concentration (Cmax) for the post-TA period was 40.2 μIU/mL (95% credible interval: 13.2, 65.7) with placebo and 16.7 μIU/mL (95% CI: 1.76, 40.1) with ertugliflozin. There was a 99.13% probability that the ertugliflozin Cmax was lower than that for placebo. In conclusion, four once-daily doses of oral ertugliflozin (0.05 mg/kg) given prior to and again following IA TA administration, attenuated the rise in plasma insulin concentrations in non-insulin-dysregulated horses.
The implantation period is crucial for the establishment of pregnancies in cows. Interferon τ (IFNτ) is produced during early implantation and acts in autocrine, paracrine and endocrine fashions on other endocrine systems. One of these is the insulin-like growth factor 1 (IGF-1) system, which is important for cell growth, proliferation, and therefore pregnancy establishment. This study investigated the effect of IFNτ on the expression of hepatic IGF-binding proteins (IGFBPs) in vitro. Primary bovine hepatocytes in a 2D sandwich culture model were stimulated with recombinant bovine IFNτ (rbIFNτ; 0.1-10.0 ng/mL) for six hours. The mRNA expression of IGFBP-1 to -7 and acid labile subunit (ALS) was measured using qRT‒PCR, and protein production was confirmed using western ligand blotting. All the IGFBPs (1-7) and ALS were expressed at basal levels in primary bovine hepatocytes, with IGFBP-2 to -4 secreted at appreciable concentrations in the medium. The expression of IGFBP-2 to -6 was stimulated by IFNτ, (treatment with rbIFNτ vs. control; IGFBP-2: for 0.5 ng/mL rbIFNτ, p = 0.0166; IGFBP-3: for 0.5 ng/mL, 5.0 ng/mL, and 10.0 ng/mL rbIFNτ, p = 0.0293, p = 0.0252, and p = 0.0099; IGFBP-4: for 0.5 ng/mL rbIFNτ, p = 0.0024; IGFBP-5: for 0.5 ng/mL and 10 ng/mL rbIFNτ, p = 0.0008 and p = 0.0421; IGFBP-6: for 0.1-10.0 ng/mL rbIFNτ, p = 0.0498-0.0022). These results indicate modulation of the IGF-system through IFNτ, which may contribute to adaptations supporting the early establishment of pregnancies in cattle.
