Disease & heat resistance

Metabolic indicators of heat-tolerant phenotypes in cattle: insights from blood metabolomics of Angus and Nellore under natural heat stress

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Abstract

Improving heat-tolerace is important for sustainable livestock production, particularly in regions facing rising temperatures. Angus (Bos taurus) and Nellore (Bos indicus) represent two contrasting genetic backgrounds for thermotolerance, providing a useful model to identify metabolic traits linked to resilience. This study applied untargeted blood metabolomics to characterize how these breeds respond to natural heat stress (HS) and to identify metabolites with potential value as physiological indicators in breeding programs. Blood samples were collected from five sunlight exposed animals per breed (Nellore and Angus) in early February 2016, during peak HS, and again in mid-June 2016, during the cooler season. Whole-blood profiles were generated using untargeted metabolomics (liquid chromatography combined with an Orbitrap mass spectrometer) and evaluated with multivariate analyses (hierarchical clustering, principal component analysis, orthogonal-projections to latent structures discriminant analysis, and variables' importance in projection analysis). Pathway analysis was performed using B. taurus and B. indicus libraries, as reported on Kyoto Encyclopedia of Genes and Genomes. A breed multivariate separation was clear under HS, with Nellore showing a metabolic configuration consistent with efficient energy management and minimal accumulation of stress-related intermediates. Angus, in contrast, exhibited metabolic patterns suggestive of increased lipid mobilization and mitochondrial burden, reflected in higher levels of long-chain acyl-carnitines and lysophospholipids. Comparisons between HS and post-HS periods showed that several metabolite classes, including amino acids, peptides, phospholipids, and nucleotide derivatives, were consistently affected in both breeds, though often with opposite directions of change. Notably, among 22 common discriminating metabolites phospholipids and lysophospholipids showed opposite accumulation values. Particularly, we found 7 phospholipids and hydrolytic products, including LysoPC(20:4(8Z,11Z,14Z,17Z)), LysoPE(22:2(13Z,16Z)/0:0), LysoPC(24:0), LysoPE(24:0/00), PA(20:4(5Z,8Z,11Z,14Z)e/2:0), PE(18:3(9Z,12Z,15Z)/P-16:0), and PC(14:1(9Z)/14:1(9Z)), that were significantly (p < 0.05) higher in the Angus-HS group (cumulative Log2Fold-Change = 3.73) when compared with Nellore-HS group (cumulative Log2Fold-Change = -7.95), sustaining the hypothesis of differences in cell-membrane dynamics and oxidative balance having a role into heat tolerance in Nellore. Additionally, pathway analyses indicated purine metabolism and porphyrin-related routes as shared components of the HS response. Among the common purine metabolites affected by HS we found 5-aminoimidazole ribotide (AIR), which was at a lower level in Nellore (-1.92; p < 0.05) than Angus (-0.34; p < 0.05) under HS conditions. 5-AIR is an intermediate in the purine biosynthesis pathway, then its reduction could signal a shift in nucleotide biosynthesis or a redistribution of purine intermediates in response to the physiological demands imposed by HS. Also, a reduction of cAMP (a key metabolite) in both breeds reflected its role as a central mediator of HS adaptation, with more marked depletion in Nellore, thus suggesting a more efficient activation of stress-regulatory mechanisms. These differences support the hypothesis that thermotolerant cattle adopt strategies that minimize the energetic cost of maintaining homeostasis during heat exposure.

Keywords: 2026

How to Cite:

Rocchetti, G., Errico, M., Capra, E., Milanesi, M., Fappani, , Garcia, J., de Paula Nogueira, G., Utsunomiya, Y., Lucini, L., Perez O’Brien, A. & Ajmone Marsan, P., (2026) “Metabolic indicators of heat-tolerant phenotypes in cattle: insights from blood metabolomics of Angus and Nellore under natural heat stress”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2286653. doi: https://doi.org/10.31274/wcgalp.24080

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