Integrative Analysis of Energy Partition Patterns and Plasma Metabolomics Profiles of Modern Growing Pigs Raised at Different Ambient Temperatures

Abstract

This study explores the energy partition patterns of modern growing pigs at 25 kg and 65 kg raised at gradient-ambient temperatures. It also investigates the underlying changes in plasma under such conditions, based on the integrative analysis of indirect calorimetry and non-target metabolomics profiling. Thirty-six barrows with initial BW of 26.4 ± 1.9 kg and 24 barrows with initial BW of 64.2 ± 3.1 kg were successively allotted to six respiration chambers with ambient temperatures set as 18 °C, 21 °C, 23 °C, 27 °C, 30 °C, and 32 °C, and four respiration chambers with ambient temperatures set as 18 °C, 23 °C, 27 °C, and 32 °C, respectively. Each pig was kept in an individual metabolic crate and consumed feed ad libitum, then transferred into the respiration chamber after a 7-day adaptation period for 5-day indirect calorimetry assay and 1-day fasting. As the ambient temperature increased from 18 °C to 32 °C, the voluntary feed intake, metabolizable energy intake, nitrogen intake, and retention, total heat production, and energy retention as a protein of growing pigs at 25 kg and 65 kg all linearly decreased (p < 0.05), with greater coefficients of variation for pigs at 65 kg when temperatures changed from 18 °C to 32 °C. The cortisol and thyroid hormone levels in the plasma of 25 kg pigs linearly decreased as the ambient temperature increased from 18 °C to 32 °C (p < 0.05), and 13 compounds were identified through metabolomics analysis, including up-regulated metabolites involved in fatty acid metabolism, such as adrenic acid and down-regulated metabolites involved in amino acid metabolism, such as spermidine at 32 °C. These results suggested that modern growing pigs at heavier bodyweight were more sensitive to high temperatures on energy intake and partition. Most of the identified metabolites altered at high ambient temperatures are associated with suppressed fatty acid oxidation and elevated lipogenesis and protein degradation.

Hydroxy Selenomethionine Improves Meat Quality through Optimal Skeletal Metabolism and Functions of Selenoproteins of Pigs under Chronic Heat Stress

“…Acute heat stress activates the hypothalamo-pituitary-adrenal axis, which leads to the release of cortisol [46]. Early studies reported CHS-induced decrease of serum cortisol in pigs [42,48,49]. In the present study, CHS led to significant reduction in serum cortisol concentration (Figure 4A), which may be due to the decreased motion of the pigs.…”

Non-targeted Metabolomics Analysis Based on LC–MS to Assess the Effects of Different Cold Exposure Times on Piglets

“…In the present study, the level of citric acid was upregulated only in the 6-h cold exposure group compared with the NT group, which may be associated with the effects of different cold conditions. The pigs suffered longer cold stress times (24, 48 h, and 5 days), and variations in the citric acid level were not detected ( Zhang et al, 2017 ; Zhang et al, 2020 ). Marai and Habeeb (2010) noted that the citric acid contents also decreased in the milk of Friesian cows and semen of buffalos under high-temperature conditions.…”

“…Except for the differential metabolites between the cold exposure groups and the control, many of the identified metabolites did not show differences; however, some differential metabolites have been observed under different cold stress conditions in previous studies. For example, deoxyuridine, indoleacetic acid, histidine, phenylacetylglycine, enterostatin, methoxyacetic acid, dihydroxyfumarate, creatinine, and oxypurinol were identified as differential metabolites in the serum or cecal mucosa samples under long-term cold stress conditions ( Zhang et al, 2020 ; Yang et al, 2021 ). Researchers have pointed out that metabolites are mainly associated with the physiological activities of energy metabolism and muscle contraction ( Zhang et al, 2020 ; Yang et al, 2021 ).…”

Effects of Ambient Temperature on the Performance and Thermoregulatory Responses of Commercial and Crossbred (Brazilian Piau Purebred Sires × Commercial Dams) Growing-Finishing Pigs

“…Accordingly, Kouba et al [ 32 ] reported a decrease in thyroid gland weight by 23% at 31 °C compared to pair-fed pigs reared at 20 °C. In addition, Zhang et al [ 33 ] reported lower T 3 and T 4 levels in 25 kg BW pigs when ambient temperature increased from 18 °C to 32 °C. The current study shows that high ambient temperature results in an overall decrease in thyroid hormone concentrations.…”