Fatty acid (FA) metabolism depends on tissue dynamics, with liver having a key role. We examine the ability of cis-acting variants affecting gene expression (cis-eQTLs) to capture additive genetic variance for a total of 68 traits (8 carcass traits and the content of 20 FAs in adipose tissue, liver and muscle) in a population of 332 Duroc pigs with genotypes for 37,700 autosomal SNPs. A total of 1,601 hepatic cis-eQTLs tagged by 1,312 cis-SNPs were used to build a cis-Genomic Relationship Matrix (cis-GRM) and compare it to the GRM built with a set of 36,388 remaining SNPs (rem-GRM). We examined the power of the cis-GRM at capturing heritability (h2) based on four genomic-based models: M1 with a GRM (tot-GRM) built with the totality of 37,700 SNPs; M2 with the cis-GRM only; M3 with the rem-GRM only; and M4 with both the cis-GRM and the rem-GRM. Compared to the h2 estimated from M1 (hM12), the equivalent from M2 (hM22) was best for adipose tissue with a non-zero estimate of hM22in 19 out of 20 FAs and averaging 96.27% of hM12. In muscle tissue, hM22 was > 0 in 4 FAs and averaging 111.84% of hM12. In contrast, the estimated hM22 for FA content in liver was > 0 in 10 FAs and averaged 61.87% of hM12. Finally, for carcass traits hM22 was > 0 for all 8 traits and averaged 76.32% of hM12. The exceptional performance of M2 at capturing genetic variation for FA in adipose tissue was attributed to the numerical stability of FA content in adipose tissue compared to liver or muscle. To determine the significance of the performance of M2, we ran 10,000 random permutation tests of a poor-performer trait, carcass weight (CWT) (hM22 = 49.25% of hM12); and a good-performer trait, dihomo-γ-linolenic acid (C20:3(n-6)) in adipose tissue (hM22 = 109.96% of hM12). The empirical p-values were 98.85%, and 0.10% for CWT and C20:3(n-6) respectively, indicating that a random set of 1,312 SNP could perform as good or better than M2 for CWT almost always, while almost never could rival M2 for C20:3(n-6). Hence, C20:3(n-6) content is affected by the pleiotropic activity of all cis-eQTL and the major-effect cis-eQTL of FADS1. Our results reflect the life-long activity of cis-eQTL genes and demonstrate that, under a sound biological context, a low-density SNP panel derived from cis-eQTL can be used to capture a significant amount of additive genetic variance for FA composition in adipose tissue.
Abstract Chronic heat stress induces systemic inflammation and impairs growth performance in feedlot livestock. We sought to determine if anti-inflammatory interventions could improve muscle growth and efficiency in heat-stressed finishing lambs. Commercial wethers (40.8 ± 0.7 kg) were fed under heat stress (40 °C) and administered 0.15 mg/kg injectable dexamethasone every 72 h (n = 11), 1200 mg oral fish oil twice daily (n = 11), or no intervention (n = 11). Pair-fed controls were housed under thermoneutral conditions (19 °C, n = 12). Lambs were necropsied after 30 d. Heat stress-induced inflammation was characterized by greater (P < 0.05) circulating (i.e., extracellular) heat shock protein 70 (HSP70) and TNFα that followed a modest, transient increase (P < 0.05) in circulating cortisol. Heat stress also reduced (P < 0.05) circulating eicosapentaenoic acid (EPA) and skeletal muscle (i.e., intracellular) HSP70, which are anti-inflammatory. Daily fish oil partially or fully resolved (P < 0.05) heat stress effects on TNFα, cortisol, EPA, and intramuscular HSP70, but not circulating HSP70. Dexamethasone partially or fully resolved (P < 0.05) heat stress effects on cortisol, EPA, and intramuscular HSP70 but did not resolve TNFα and further worsened (P < 0.05) circulating HSP70. Heat stress-induced insulin resistance was indicated by greater (P < 0.05) circulating insulin and IGF-1 that was resolved (P < 0.05) by fish oil but not dexamethasone. Final bodyweights, average daily gain, and gain-to-feed ratios indicative of growth efficiency were reduced (P < 0.05) by heat stress but recovered (P < 0.05) by fish oil and dexamethasone. Live-animal estimates of ribeye area and fat-free muscle mass were reduced (P < 0.05) by heat stress, as was actual mass for 4 of 6 individual muscles weighed at necropsy. Poor muscle growth in heat-stressed lambs was facilitated in part by reductions (P < 0.05) in total (i.e., pax7+) and tended reductions (P < 0.10) in differentiated (i.e., myogenin+) myoblast populations. Differentiated (but not total) myoblasts tended to be recovered (P < 0.10) by fish oil and dexamethasone interventions, resulting in full or partial recovery of several muscle growth indicators. These findings show that induction of systemic inflammation contributes substantially to impaired muscle growth and efficiency in heat-stressed feedlot lambs. As such, inflammation is a feasible mechanistic target for improving outcomes of heat stress with anti-inflammatory bioactive nutrients.
Abstract The objective of the present study was to assess the effect of length of stay in first postpartum pen (LSPP) on BCS change (ΔBCS), health status, culling within the first 60 days in milk (DIM, CULL60), culling through 305 DIM (CULL305), milk yield, milk components, and reproductive performance of Holstein cows. A total of 817 multiparous Holstein cows from two farms were enrolled in cohorts of 45 to 50 cows every two weeks at 21±3 d before parturition. At calving, cows were randomly assigned to one of three LSPP groups: 7 (n = 260), 14 (n = 283) or 21 (n = 274) DIM. Within farm, cows were managed under the same pre- and postpartum feeding programs. Serum calcium (Ca) was assessed within 48 h after calving, and ΔBCS was assessed between calving and 28±3 DIM. Serum β-hydroxybutyrate was assessed at 7±3 and 14±3 DIM to assess hyperketonemia (≥1.2 mmol/L). Health events within the first 30 DIM were recorded, and cows were categorized into one of four groups: 1) non-disease (ND); 2) cows with only hyperketonemia (KET); 3) cows with hyperketonemia plus one other health condition (KET+); or 4) cows experiencing ≥1 health event excluding hyperketonemia (SICK). Cows sold or died were classified as culling to assess CULL60 and CULL305. Presence of a functional corpus luteum (CL, ≥1.0 ng/mL) was determined at 28±3 DIM using serum progesterone. Pregnancy per AI (PAI) for first service and time to pregnancy up to 305 DIM were assessed. Milk yield, milk fat, milk protein, and energy-corrected milk (ECM) were assessed at the first DHI test and up to 305 DIM. Data were analyzed using linear mixed models, generalized linear mixed models, or Cox proportional hazard models. Health status, ΔBCS, Ca, CULL60, functional CL, milk yield, milk components, and ECM at first DHI test did not differ (P > 0.05) among LSPP groups. Cows with an LSPP of 7 DIM tended (P = 0.081) to have reduced CULL305 with shorter time to pregnancy up to 305 DIM compared to cows with an LSPP of 21 DIM (P = 0.005). Compared to cows with an LSPP of 21 DIM, cows with an LSPP of 7 DIM had increased cumulative 305 DIM milk fat by 9.4% (P = 0.029) and ECM by 9.6% (P = 0.017), and tended to have increased milk protein by 8.2% (P = 0.059), whereas cows with an LSPP of 14 DIM did not differ. These findings show that ΔBCS, health status, and CULL60 were not affected by LSPP in multiparous cows. However, cows with an LSPP of 7 DIM had improved pregnancy and achieved greater cumulative milk fat and ECM yields up to 305 DIM.
Diabetic cardiomyopathy (DCM), a diabetes-specific myocardial pathology, is a significant contributor to diabetes-related heart failure. Endoplasmic reticulum (ER) stress plays a crucial role in DCM, yet its upstream regulatory mechanisms remain incompletely elucidated. Cellular heterogeneity in DCM was investigated by analyzing single-cell transcriptomic data from the Gene Expression Omnibus. A mouse DCM model was established and validated using echocardiography, serum biochemical assays, and histological analysis. TNFAIP1 expression was detected by Western blot. A high glucose-induced DCM cellular model was constructed using HL-1 cardiomyocytes and neonatal cardiomyocytes (NMCMs). Cell injury and TNFAIP1 expression were assessed via TUNEL staining, Annexin V/PI staining, CellRox probe, RT-qPCR, and Western blot. Finally, a TNFAIP1-knockdown DCM mouse model was constructed, and the in vitro results were further validated by echocardiography, serum biochemical assays, histological analysis, and other methods. Single-cell analyses revealed the enrichment of TNFAIP1+ cardiomyocytes in DCM, with their differentially expressed genes enriched in p38 MAPK and apoptosis signaling pathways. TNFAIP1 expression was significantly upregulated in both DCM mouse and cellular models. TNFAIP1 overexpression activated p38 MAPK-mediated ER stress, increased ROS levels, and promoted apoptosis, whereas TNFAIP1 knockdown produced the opposite effects. These effects were significantly reversed by the p38 MAPK pathway inhibitor SB203580, the ER stress inhibitor TUDCA, and the ER stress inducer Thapsigargin. Finally, in vivo experiments further confirmed that TNFAIP1 knockdown ameliorated the progression of myocardial injury in DCM mice. TNFAIP1 promotes DCM progression via the p38 MAPK-mediated ER stress-apoptosis axis, identifying TNFAIP1 as a novel potential therapeutic target for DCM.
This cohort study quantifies the long-term effects of highly pathogenic avian influenza (HPAI) H5N1 on cumulative milk yield and milk yield trajectories during the affected lactation, and carryover effects in the subsequent lactation; and evaluates the relationship between antibody response and affected status under field conditions. A cohort of 1,845 lactating Holstein cows from a commercial dairy herd affected by HPAI H5N1 was monitored across current and subsequent lactations. Affected status was defined as >= 30% decline in daily milk yield relative to a 7-d baseline. Milk yield trajectories were analyzed using generalized additive mixed models with spline-based smooth terms for time, including a random intercept for cow and fixed effects for parity, stage of lactation, and HPAI affected status. Associations between antibody response and affected status were evaluated using multivariable logistic and linear regression models, adjusted for parity and stage of lactation. Affected animals (n = 772) had an average cumulative milk loss of 9.6% (1,109 kg) per 305 d, representing an average loss of $569 per affected cow. Greater losses occurred in multiparous (-12.4%) than primiparous cows (-3.9%). Retention into the subsequent lactation was similar between affected and unaffected cows (69.8% vs. 69.2%, respectively), and no evidence of carryover effects was detected. Based on post-outbreak serologic testing (n = 121), multiparous cows had greater odds of testing ELISA-positive for antibodies to HPAI than primiparous cows (odds ratio [OR] = 2.48, 95% CI: 1.07-6.28). The adjusted predicted proportions of cows classified as affected based on the milk yield decline criterion during the HPAI outbreak were 63.2% among ELISA-positive cows, 42.1% among ELISA-suspect cows, and 33.2% among ELISA-negative cows. The ELISA-positive cows had greater odds of experiencing severe milk yield decline than ELISA-negative cows (OR = 3.45, 95% CI: 1.44-8.69). Cows with stronger antibody response had greater odds of being classified as affected based on milk yield decline (OR = 0.51 per 0.05 sample-to-negative increase; 95% CI: 0.35-0.75). Overall, cows affected during the HPAI outbreak had substantial milk yield and economic losses during the affected lactation. Limited recovery was most evident among multiparous cows and among cows affected in early lactation, regardless of parity. No evidence of carryover effects was observed in the subsequent lactation. Stronger post-outbreak antibody responses were associated with affected status during the outbreak, defined by milk yield decline as a clinically relevant sign.
