Intestinal metabolomics of juvenile lenok (Brachymystax lenok) in response to heat stress

Integrating metabolomics and transcriptomics to analyze the differences of breast muscle quality and flavor formation between Daweishan mini chicken and broiler

The quality and flavor of chicken are affected by muscle metabolites and related regulatory genes, and the molecular regulation mechanism of meat quality is different among different breeds of chicken. In this study, 40 one-day-old Daweishan mini chicken (DM) and Cobb broiler (CB) were selected from each group, with 4 replicates and 10 chickens in each replicate. The chickens were reared until 90 d of age under the same management conditions. Then, metabolomics and transcriptomics data of 90-day-old DM (n = 4) and CB (n = 4) were integrated to analyze metabolites affecting breast muscle quality and flavor, and to explore the important genes regulating meat quality and flavor related metabolites. The results showed that a total of 38 significantly different metabolites (SDMs) and 420 differentially expressed genes (DEGs) were detected in the breast muscle of the 2 breeds. Amino acid and lipid metabolism may be the cause of meat quality and flavor difference between DM and CB chickens, involving metabolites such as L-methionine, betaine, N6, N6, N6-Trimethyl-L-lysine, L-anserine, glutathione, glutathione disulfide, L-threonine, N-Acetyl-L-aspartic acid, succinate, choline, DOPC, SOPC, alpha-linolenic acid, L-palmitoylcarnitine, etc. Important regulatory genes with high correlation with flavor amino acids (GATM, GSTO1) and lipids (PPARG, LPL, PLIN1, SCD, ANGPTL4, FABP7, GK, B4GALT6, UGT8, PLPP4) were identified by correlation analysis, and the gene-metabolite interaction network of breast muscle mass and flavor formation in DM chicken was constructed. This study showed that there were significant differences in breast metabolites between DM and CB chickens, mainly in amino acid and lipid metabolites. These 2 kinds of substances may be the main reasons for the difference in breast muscle quality and flavor between the 2 breeds. In general, this study could provide a theoretical basis for further research on the molecular regulatory mechanism of the formation of breast muscle quality and flavor differences between DM and CB chickens, and provide a reference for the development, utilization and genetic breeding of high-quality meat chicken breeds.

Comprehensive analysis of butyric acid impact on immunology, histopathology, gene expression, and metabolomic responses in pacific shrimp experiencing cold stress

In this study, our objective was to investigate the impact of dietary butyric acid (BA) on the homeostasis mechanism of Pacific shrimp under cold stress. Specifically, we analyzed its effects on immunity, antioxidant capacity, gene expression, and metabolomics response. To carry out this research, Litopenaeus vannamei were fed a diet supplemented with BA for 8 weeks. Following this feeding period, a total of 180 shrimp, with an average weight of 12.76 ± 0.38 g, were exposed to cold conditions, with the temperature decreasing from 28 °C to 14 °C within an hour. The results of our study revealed survival rates ranging from 90 % to 100 %. Shrimp that were fed a diet containing 1.5 % BA exhibited a significant increase in acid phosphatase (ACP) and alkaline phosphatase (AKP) activity. Conversely, the control groups showed an increase in aspartate aminotransferase (AST) and alanine transaminase (ALT) activity. Shrimp that consumed diets containing 1.5 % BA displayed the lowest malondialdehyde (MDA) levels with the highest superoxide dismutase (SOD) content. The shrimp fed the BA diet exhibited tightly organized hepatic tubules with a star-shaped lumen filled with numerous B and R cells. Furthermore, shrimp fed the BA diet demonstrated a significant increase in caspase 3 (CASP) expression. There were no significant variations in the expression levels of prophenoloxidase (ProPO), manganese superoxide dismutase (MnSOD), and glutathione S-transferase (GST) The metabolites of Dl-carnitine, acetyl-l-carnitine, propionylcarnitine, hexanoylcarnitine, palmitoylcarnitine, decanoylcarnitine, and Dl-carnitine exhibited significantly increased expression in shrimp that were fed BA, suggesting their role in the lipolysis process. Based on the findings, adding 2 % BA to the diet of Pacific shrimp helps reduce inflammation and oxidative stress when they are under cold stress.

Influences of Stocking Density on Antioxidant Status, Nutrients Composition, and Lipid Metabolism in the Muscles of Cyprinus carpio under Rice-Fish Co-Culture

Cyprinus carpio is a significant freshwater species with substantial nutritional and economic value. Rice-carp co-culture represents one of its principal cultivation methods. However, in the system, the optimal farming density for carp and the impact of high stocking density on their muscle nutritional composition have yet to be explored. Thus, the objective of the current study was to investigate the influences of stocking density on the muscle nutrient profiles and metabolism of C. carpio in rice-fish co-culture systems. Common carp were cultured at three stocking densities, low density (LD), medium density (MD), and high density (HD), over a period of 60 days. Following this, comprehensive analyses incorporating physiological, biochemical, and multi-omics sequencing were conducted on the muscle tissue of C. carpio. The results demonstrated that HD treatment led to a reduction in the antioxidant capacity of C. carpio, while resulting in elevated levels of various fatty acids in muscle tissue, including saturated fatty acids (SFAs), omega-3 polyunsaturated fatty acids (n-3 PUFAs), and omega-6 polyunsaturated fatty acids (n-6 PUFAs). The metabolome analysis showed that HD treatment caused a marked reduction in 43 metabolites and a significant elevation in 30 metabolites, primarily linked to lipid and amino acid metabolism. Additionally, transcriptomic analysis revealed that the abnormalities in lipid metabolism induced by high-stocking-density treatment may be associated with significant alterations in the PPAR signaling pathway and adipokine signaling pathway. Overall, our findings indicate that in rice-fish co-culture systems, high stocking density disrupted the balance of antioxidant status and lipid metabolism in the muscles of C. carpio.

High-Temperature-Induced Differential Expression of miRNA Mediates Liver Inflammatory Response in Tsinling Lenok Trout (Brachymystax lenok tsinlingensis)

High-temperature stress poses a significant environmental challenge for aquatic organisms, including tsinling lenok trout (Brachymystax lenok tsinlingensis). This study aimed to investigate the role of microRNAs (miRNAs) in inducing liver inflammation in tsinling lenok trout under high-temperature stress. Tsinling lenok trout were exposed to high-temperature conditions (24 °C) for 8 h, and liver samples were collected for analysis. Through small RNA sequencing, we identified differentially expressed miRNAs in the liver of high-temperature-stressed tsinling lenok trout compared to the control group (maintained at 16 °C). Several miRNAs, including novel-m0105-5p and miR-8159-x, showed significant changes in expression levels. Additionally, we conducted bioinformatics analysis to explore the potential target genes of these differentially expressed miRNAs. Our findings revealed that these miRNA target genes are involved in inflammatory response pathways, such as NFKB1 and MAP3K5. The downregulation of novel-m0105-5p and miR-8159-x in the liver of high-temperature-stressed tsinling lenok trout suggests their role in regulating liver inflammatory responses. To validate this, we performed a dual-luciferase reporter assay to confirm the regulatory relationship between miRNAs and target genes. Our results demonstrated that novel-m0105-5p and miR-8159-x enhance the inflammatory response of hepatocytes by promoting the expression of NFKB1 and MAP3K5, respectively. In conclusion, our study provides evidence that high-temperature stress induces liver inflammation in tsinling lenok trout through dysregulation of miRNAs. Understanding the molecular mechanisms underlying the inflammatory response in tsinling lenok trout under high-temperature stress is crucial for developing strategies to mitigate the negative impacts of environmental stressors on fish health and aquaculture production.

Effect of heat stress on blood biochemistry and energy metabolite of the Dazu black goats

The objective of this study was to determine the effects of heat stress (HS) on physiological, blood biochemical, and energy metabolism in Dazu black goats. Six wether adult Dazu black goats were subjected to 3 experimental periods: high HS (group H, temperature-humidity index [THI] > 88) for 15 d, moderate HS (group M, THI was 79-88) for 15 d, and no HS (group L, THI < 72) for 15 d. Rectal temperature (RT) and respiratory rate (RR) were determined on d 7 and 15 of each period, and blood samples were collected on d 15 of each period. All goats received glucose (GLU) tolerance test (GTT) and insulin (INS) tolerance test on d 7 and d 10 of each period. The results showed that HS decreased dry matter intake (DMI) and INS concentration (p < 0.05), and increased RT, RR, non-esterified fatty acid (NEFA), cortisol (COR), and total protein (TP) concentrations (p < 0.05). Compared to group L, the urea nitrogen (BUN) concentration increased and GLU concentration decreased in group H (p < 0.05). During the GTT, the area under the curve (AUC) of GLU concentrations increased by 12.26% (p > 0.05) and 40.78% (p < 0.05), and AUC of INS concentrations decreased by 26.04 and 14.41% (p < 0.05) in groups H and M compared to group L, respectively. The INS concentrations were not significant among the three groups (p > 0.05) during the ITT. A total of 60 differentially expressed metabolites were identified in response to groups H and M. In HS, changes in metabolites related to carbohydrate metabolism and glycolysis were identified (p < 0.05). The metabolites related to fatty acid β-oxidation accumulated, glycogenic and ketogenic amino acids were significantly increased, while glycerophospholipid metabolites were decreased in HS (p < 0.05). HS significantly increased 1-methylhistidine, creatinine, betaine, taurine, taurolithocholic acid, inosine, and hypoxanthine, while decreasing vitamin E in blood metabolites (p < 0.05). In summary, HS changed the metabolism of fat, protein, and energy, impaired GLU tolerance, and mainly increased amino acid metabolism to provide energy in Dazu black goats.

Redox state and metabolic responses to severe heat stress in lenok Brachymystax lenok (Salmonidae)

In order to provide new insights into the physiological responses of lenok (Brachymystax lenok: Salmonidae) to acute and severe heat stress (25°C, 48 h), dynamic changes in redox state and metabolic responses are studied combined biochemical index and non-targeted metabolome. Nicotinamide adenine dinucleotide (NAD⁺) consumption causes significant increases in ratio of reduced NADH to NAD⁺ and ratio of reduced nicotinamide adenine dinucleotide phosphate (NADPH) to NADP⁺, which induced the redox imbalance in heat stressed lenok. Lowered reduced glutathione/oxidized glutathione (GSH/GSSG) ratios suggested that more oxidized conditions occurred in heat-stressed lenok, leading to membrane lipid oxidation. The first few hours of heat stress promoted the activity of enzymes involved in anaerobic glycolysis (hexokinase, pyruvate kinase, lactic dehydrogenase) and glutamicpyruvic transaminase and glutamic oxaloacetic transaminase, which might lead to consumption of many carbohydrates and amino acid catabolism. These enzyme activities decreased with time in a possible compensatory strategy to manage anabolic and catabolic metabolism, maintaining the redox homeostasis. After 48 h of recovery, NAD⁺, carbohydrate levels and enzyme activities had returned to control levels, whereas many amino acids were consumed for repair and new synthesis. GSH remained at levels lower than controls, and the more oxidized conditions had not recovered, aggravating oxidative damage. Glutamic acid, glutamine, lysine and arginine may play important roles in survival of heat-stressed lenok.