Transport stress induces heart damage in newly hatched chicks via blocking the cytoprotective heat shock response and augmenting nitric oxide production

Low temperature alleviated the adverse effects of simulated transport stress on the intestinal health in Chinese soft-shelled turtle Pelodiscus sinensis

Transport stress always poses a threat to aquatic animals. Transportation under low temperatures was often used to relieve transport stress in practical production of Chinese soft-shelled turtle Pelodiscus sinensis, but their effect on the turtle's intestinal barrier remains unclear. In this study, P. sinensis (initial weight 200 ± 20 g) were exposed to simulated transport stress for 12 h at control (30 °C) and low (20 °C) temperature, and then recovery for 24 h, and each treatment had 4 replicates with each replicate containing 4 turtles. The results showed that transportation induced obvious morphological and histological damages in intestinal villus, with a down-regulated expression of the tight junction related genes. Besides turtles in transport group showed an oxidative stress in intestine, which stimulated a physiological detoxification response together with apoptosis. Low temperature transport plays a mitigative effect on the transport stress of turtle intestine via relieved stress response. Specifically, the intestinal villus/crypt (V/C) ratio and the expression of tight junction genes in the low-temperature group were significantly higher compared to the control temperature group, while stress response parameters such as intestinal cortisol levels and hsp expression were significantly lower in the low-temperature group. Additionally, low temperature alleviated oxidative damage and apoptosis caused by transport stress relative to the control temperature group. However, the protective effect of low temperature on P. sinensis intestine was limited, especially after the temperature recovery stage. Overall, the findings of the present study demonstrated that transport stress would induce the disruption of intestinal integrity and oxidative damage, also activated the mucosal immunity and antioxidant enzyme system response of turtles. It was also suggested that low temperature could alleviate the adverse effects of transport stress on intestinal integrity through modulation of oxidative status and apoptosis, whereas much less impact after temperature recovery.

Inhibition of mtDNA-PRRs pathway-mediated sterile inflammation by astragalus polysaccharide protects against transport stress-induced cardiac injury in chicks

Transport stress (TS) not only weakens poultry performance but also affects animal welfare. Additionally, TS can evoke cardiac damage by triggering sterile inflammation in chicks, but the underlying mechanism is not fully understood. Here, we aimed to elucidate how TS induces sterile inflammation and heart injury and to clarify the antagonism effect of astragalus polysaccharides (APS). We randomly divided 60 chicks (one-day-old female) into 5 groups (n = 12): Control_0h (Con_0h) group (chicks were slaughtered at initiation), Control group (stress-free control), TS group (simulated TS exposure for 8 h), TS plus water (TS+W) group, and TS plus APS (TS+APS) group. Before simulation transport, the chicks of TS+W and TS+APS groups were, respectively, dietary with 100 μL of water or APS (250 μg/mL). H&E staining was employed for cardiac histopathological observation. ELISA assay was used to measure oxidative stress marker levels (GSH, GPX, GST, and MDA). A commercial kit was used to isolate the mitochondrial portion, and qRT-PCR was employed to measure the mitochondrial DNA (mtDNA) levels. Furthermore, we evaluated the activity of mtDNA-mediated NF-κB, NLRP3 inflammasome, and cGAS-STING inflammatory pathways and the expression of downstream inflammatory factors by Western Blotting or qRT-PCR. Our findings revealed that APS notably relieved TS-induced myocardial histopathological lesions and infiltrations. Likewise, the decrease in proinflammatory factors (TNF-α, IL-1β, and IL-6) and IFN-β by APS further supported this result. Meanwhile, TS caused severe oxidative stress in the chick heart, as evidenced by decreased antioxidant enzymes and increased MDA. Importantly, APS prevented mtDNA stress and leakage by reducing oxidative stress. Interestingly, TS-induced mtDNA leakage caused a series of inflammation events via mtDNA-PRRs pathways, including TLR21-NF-κB, NLRP3 inflammasome, and cGAS-STING signaling. Encouragingly, all these adverse changes related to inflammation events induced by mtDNA-PRRs activation were all relieved by APS treatment. In summary, our findings provide the first evidence that inhibition of mtDNA-PRRs pathway-mediated sterile inflammation by APS could protect against TS-induced cardiac damage in chicks.

N-carbamylglutamate supplementation induces functional egg production in layers by modulating liver transcriptome profiles

Eggs rich in polyunsaturated fatty acids (PUFA), known as functional eggs, are animal products deemed beneficial to human health and possess high economic value. The production of functional eggs involves supplementing exogenous additives with the ability to regulate lipid metabolism. As N-Carbamylglutamate (NCG) serves as an endogenous arginine synthesizer, and arginine acts as the substrate for the formation of nitric oxide (NO), the biological function of NCG is partially mediated by NO. NO is a key regulatory molecule in lipid metabolism, suggesting that NCG may also have the ability to modulate lipid metabolism. In order to assess the capacity of NCG in regulating liver lipid metabolism and its potential application in producing functional eggs, we conducted a study to investigate the effects of dietary supplementation of NCG on production performance, serum, and liver NO levels, yolk fatty acid composition, and the liver transcriptome of layers. In this study, we utilized 30 layers of the Jinghong No.1 breed, all aged 45 wk. All the birds were randomly divided into 2 groups. Each group had 5 replicates, and each replicate had 3 birds. We provided them with different diets: one group received the basic diet, and the other group's diet was supplemented with 0.08% NCG. The experiment lasted for 14 wk. The results did not reveal any positive impact of NCG on production performance. However, NCG supplementation elevated NO levels in serum and liver, along with an increase in yolk PUFA, ω-3, and ω-6 fatty acids. Liver transcriptome analysis identified 124 upregulated differentially expressed genes (DEGs) and 43 downregulated DEGs due to NCG supplementation. Functional annotation using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database highlighted 3 upregulated DEGs (CPT1A, MOGAT1, and CHKA) and 2 downregulated DEGs (FASN and ETNPPL) associated with lipid metabolism. Pathway enrichment analysis revealed that CPT1A was enriched in the AMPK signaling pathway and the PPAR signaling pathway, while FASN was enriched in the AMPK signaling pathway. Thus, CPT1A and FASN are potential functional genes related to lipid metabolism facilitated by NCG supplementation. In summary, our study suggests that NCG supplementation modulates liver lipid metabolism, leading to the production of functional eggs in layers.

Effects of transport stress on the oxidative index, apoptosis and autophagy in the small intestine of caprine

BACKGROUND

Introducing new goat breeds or transferring adult goats from farms to slaughterhouses requires transportation, which can engender adverse effects, such as oxidative stress, pathological cell apoptosis and autophagy. Current evidence suggests that malondialdehyde (MDA) is a metabolite of lipid peroxidation during oxidative stress, while superoxide dismutase (SOD) and catalase (CAT) can alleviate injury caused by free radicals and reactive oxygen species (ROS). Meanwhile, Bcl-2, Bax, LC3B, PINK1 and Parkin are important proteins that participate in pathological cell apoptosis and autophagy. This study aimed to investigate the effects of transportation stress on oxidative stress indexes and expressions of Bcl-2, Bax, LC3B, PINK1 and Parkin in the small intestine of goats. Twelve healthy adult male goats from western Jiangxi province were randomly divided into control, 2 h transportation stress, and 6 h transportation stress groups (n = 4 per group).

RESULTS

Our results showed that MDA in the small intestine significantly increased after transportation, while SOD and CAT activities decreased, with a significantly increased apoptosis rate of the small intestine cells. The jejunum and duodenum exhibited the highest apoptosis rate in the 2 h and 6 h transportation groups, respectively. The expression of apoptosis-related genes Bcl-2 and Bax and their corresponding proteins exhibited varying degrees of down-regulation or up-regulation, while Bcl-2 and Bax genes in the small intestine were upregulated in the 6 h transportation group. In addition, autophagosomes and autophagolysosomes were found in various parts of the small intestine by transmission electron microscopy, and autophagy-related genes LC3B, PINK1 and Parkin were significantly down-regulated in the 2 h group and up-regulated in the 6 h group.

CONCLUSIONS

Our results indicate that the contents of MDA, SOD and CAT in the small intestine, the expression of pathologic apoptosis-related genes Bcl-2 and Bax, and autophagy-related genes LC3B, PINK1 and Parkin correlated with stress duration caused by transportation. Moreover, this study provides a foothold for further studies on the mechanism of transportation stress in goats and improving animal welfare.

Heat Shock Protein Response to Stress in Poultry: A Review

Compared to other animal species, production has dramatically increased in the poultry sector. However, in intensive production systems, poultry are subjected to stress conditions that may compromise their well-being. Much like other living organisms, poultry respond to various stressors by synthesising a group of evolutionarily conserved polypeptides named heat shock proteins (HSPs) to maintain homeostasis. These proteins, as chaperones, play a pivotal role in protecting animals against stress by re-establishing normal protein conformation and, thus, cellular homeostasis. In the last few decades, many advances have been made in ascertaining the HSP response to thermal and non-thermal stressors in poultry. The present review focuses on what is currently known about the HSP response to thermal and non-thermal stressors in poultry and discusses the factors that modulate its induction and regulatory mechanisms. The development of practical strategies to alleviate the detrimental effects of environmental stresses on poultry will benefit from detailed studies that describe the mechanisms of stress resilience and enhance our understanding of the nature of heat shock signalling proteins and gene expression.

Zebrafish (Danio rerio) as a model organism for screening nephrotoxic chemicals and related mechanisms

Because of essential role in homeostasis of the body fluid and excretion of wastes, kidney damage can lead to severe impacts on health and survival of humans. For most chemicals, nephrotoxic potentials and associated mechanisms are unclear. Hence, fast and sensitive screening measures for nephrotoxic chemicals are required. In this study, the utility of zebrafish (Danio rerio) was evaluated for the investigation of chemical-induced kidney toxicity and associated modes of toxicity, based on the literature review. Zebrafish has a well-understood biology, and many overlapping physiological characteristics with mammals. One such characteristic is its kidneys, of which histology and functions are similar to those of mammals, although unique differences of zebrafish kidneys, such as kidney marrow, should be noted. Moreover, the zebrafish kidney is simpler in structure and easy to observe. For these advantages, zebrafish has been increasingly used as an experimental model for screening nephrotoxicity of chemicals and for understanding related mechanisms. Multiple endpoints of zebrafish model, from functional level, i.e., glomerular filtration, to transcriptional changes of key genes, have been assessed to identify chemical-induced kidney toxicities, and to elucidate underlying mechanisms. The most frequently studied mechanisms of chemical-induced nephrotoxicity in zebrafish include oxidative stress, inflammation, DNA damage, apoptosis, fibrosis, and cell death. To date, several pharmaceuticals, oxidizing agents, natural products, biocides, alcohols, and consumer chemicals have been demonstrated to exert different types of kidney toxicities in zebrafish. The present review shows that zebrafish model can be efficiently employed for quick and reliable assessment of kidney damage potentials of chemicals, and related toxic mechanisms. The toxicological information obtained from this model can be utilized for identification of nephrotoxic chemicals and hence for protection of public health.

Dietary live yeast supplementation alleviates transport-stress-impaired meat quality of broilers through maintaining muscle energy metabolism and antioxidant status

BACKGROUND

This experiment was to investigate the effect of dietary live yeast (LY, 1 × 10¹⁰  CFU g^-1 ) supplementation on serum metabolic parameters, meat quality as well as antioxidant enzyme activity of transported broilers. A total of 192 one-day-old broilers were randomly assigned to four treatments with six replicates and eight chicks per replicate: a basal diet without transportation (CON), a basal diet containing 0 (T), 500 (T + LY₅₀₀ ) and 1000 mg kg^-1 (T + LY₁₀₀₀ ) LY with 3 h of transportation after feeding for 42 days, respectively. The serum and muscle samples of broilers were collected immediately after 3 h of transportation.

RESULTS

A higher (P < 0.05) final body weight and average daily weight gain were observed in T + LY₁₀₀₀ group compared with CON and T groups. The T + LY₁₀₀₀ group reduced (P < 0.05) the serum lactate contents and improved (P < 0.05) the pH_24h and decreased (P < 0.05) the drip loss in muscles of transported-broilers. Also, the T + LY₁₀₀₀ group enhanced (P < 0.05) the total-antioxidant capacity and reduced (P < 0.05) the malondialdehyde in serum and muscles. Besides, the messenger RNA (mRNA) expression of avian uncoupling protein (avUCP) in muscles was down-regulated (P < 0.05) of T + LY₁₀₀₀ group compared with T group.

CONCLUSION

Dietary LY supplementation alleviates transport-stress-impaired meat quality of broilers through maintaining muscle energy metabolism and antioxidant status. Therefore, LY may serve as a potential protector for broilers under transport stress in the future. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Non-Targeted Metabolomic Analysis of Chicken Kidneys in Response to Coronavirus IBV Infection Under Stress Induced by Dexamethasone

Stress in poultry can lead to changes in body metabolism and immunity, which can increase susceptibility to infectious diseases. However, knowledge regarding chicken responses to viral infection under stress is limited. Dexamethasone (Dex) is a synthetic glucocorticoid similar to that secreted by animals under stress conditions, and has been widely used to induce stress in chickens. Herein, we established a stress model in 7-day-old chickens injected with Dex to elucidate the effects of stress on IBV replication in the kidneys. The metabolic changes, immune status and growth of the chickens under stress conditions were comprehensively evaluated. Furthermore, the metabolic profile, weight gain, viral load, serum cholesterol levels, cytokines and peripheral blood lymphocyte ratio were compared in chickens treated with Dex and infected with IBV. An LC-MS/MS-based metabolomics method was used to examine differentially enriched metabolites in the kidneys. A total of 113 metabolites whose abundance was altered after Dex treatment were identified, most of which were lipids and lipid-like molecules. The principal metabolic alterations in chicken kidneys caused by IBV infection included fatty acid, valine, leucine and isoleucine metabolism. Dex treatment before and after IBV infection mainly affected the host’s tryptophan, phenylalanine, amino sugar and nucleotide sugar metabolism. In addition, Dex led to up-regulation of serum cholesterol levels and renal viral load in chickens, and to the inhibition of weight gain, peripheral blood lymphocytes and IL-6 production. We also confirmed that the exogenous cholesterol in DF-1 cells promoted the replication of IBV. However, whether the increase in viral load in kidney tissue is associated with the up-regulation of cholesterol levels induced by Dex must be demonstrated in future experiments. In conclusion, chick growth and immune function were significantly inhibited by Dex. Host cholesterol metabolism and the response to IBV infection are regulated by Dex. This study provides valuable insights into the molecular regulatory mechanisms in poultry stress, and should support further research on the intrinsic link between cholesterol metabolism and IBV replication under stress conditions.

Transport Stress Induced Cardiac NO-NOS Disorder Is Mitigated by Activating Nrf2/HO-1/NQO1 Antioxidant Defense Response in Newly Hatched Chicks

With the development of the intensive poultry industry, the health problems of chickens caused by transportation have attracted more and more attention. Transport stress reduces performance, immune function, and meat quality in chicks, which has become one of the most important factors that endanger the development of the poultry industry. Currently, studies on the effects of transport stress have mainly focused on the performance of livestock and poultry to be slaughtered. However, the effects of transport stress on heart damage and oxidative stress in newborn chicks have not been reported. In this study, we selected newborn chicks as the object. This study was intended to explore the effects of transport stress on the heart damage of newly hatched chicks. The findings suggested that transport stress could cause oxidative stress in the hearts of newly hatched chicks by increasing the levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and decreasing the contents of Total antioxidant capacity (T-AOC), and the activities of antioxidant enzymes (SOD), together with increasing the activities of antioxidant enzymes (Catalase (CAT) and Glutathione S-transferase (GST)). Transport stress disrupted the balance between oxidation and antioxidant systems. The Nrf2 signaling pathway was activated by transport stress and triggered the transcription of antioxidant signaling. In short, transport stress-induced nitric oxide (NO)—nitric oxide synthases (NOS) system metabolic disorders and cardiac oxidative stress are mitigated by activating the nuclear factor-erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1)/NAD(P)H quinone oxidoreductase-1 (NQO1) antioxidant defense response in newly hatched chicks.

Astragalus polysaccharide alleviates transport stress-induced heart injury in newly hatched chicks via ERS-UPR-Autophagy dependent pathway

Transport stress (TS) not only affects animal welfare but also eventually leads to higher morbidity and mortality. Moreover, TS could induce heart injury in animals, but the possible mechanism has yet to be fully explored. Astragalus polysaccharide (APS) is a main active component of Radix Astragali, which has an extensive anti-stress effect. However, the effect of APS on TS-induced heart injury has not yet been elucidated. In this study, a chick model of simulated TS was used. 240 newly hatched chicks were arranged into 4 groups: Control (Con), Transport group (T), Transport + water group (TW), and Transport + APS group (TA). Before transport, the chicks of the TW and TA groups were treated with deionized water and APS (0.25 mg/mL, 100 µL) by oral drops respectively. The histopathological analysis of myocardial tissue was assessed by hematoxylin and eosin staining. qRT-PCR and Western Blotting assays were employed to measure the expression of genes and proteins. Semiquantitative PCR was performed for the X box-binding protein-1 (XBP-1) mRNA splicing assay. The results indicated that APS significantly reduced TS-induced myocardial histopathological changes. Meanwhile, TS induced endoplasmic reticulum stress (ERS), evidenced by an activation of the unfolded protein response (UPR) signaling pathway and up-regulation of ERS-markers (P < 0.05). Moreover, TS markedly triggered autophagy induction by activating AMP-activated protein kinase (AMPK), reflected by augmented LC3-II/LC3-I, AMPK phosphorylation and autophagy-related genes (ATGs) expression (P < 0.05). Importantly, our study manifested that treatment of APS could reduce TS-induced ERS and AMPK-activated autophagy, accordingly alleviating heart injury of transported chicks. In summary, these findings indicate that TS induces heart injury in chicks via an ERS-UPR-autophagy-dependent pathway, and APS as an effective therapeutic method to alleviate it.

Day-old chicken quality and performance of broiler chickens from 3 different hatching systems

In on-farm hatching systems, eggs are transported at d 18 of incubation to the broiler farm, where chickens have immediate access to feed and water after hatching. In hatchery-fed systems, newly hatched chickens have immediate access to feed and water in the hatchery and are transported to the farm thereafter. Conventionally hatched chickens can remain without access to feed and water up to 72 h after hatching until placement on the farm. The current study compared day-old chicken quality, performance, and slaughter yield of broiler chickens that were on-farm hatched (OH), hatchery-fed (HF), or conventionally hatchery-hatched (HH). The experiment was performed in 6 rooms in 1 house. Each room contained 2 duplicate pens with approximately 1,155 chickens per pen; 2 rooms with each 2 duplicate pens were assigned to 1 treatment. The experiment was repeated during 3 consecutive production cycles. Chickens originated from young parent stock flocks. Results showed that HF and OH chickens were heavier and longer than HH chickens at day (D) 1. Relative weight of stomach and intestines were highest for OH chickens. The OH chickens had worse day-old chicken quality in terms of navel condition and red hocks than HH and HF chickens. Treatments did not differ in first wk and total mortality. From D0 until slaughter age, body weight was highest for OH, followed by HF and HH. Furthermore, carcass weight at slaughter age (D40) was highest for OH chickens, followed by HF and HH chickens. Breast fillets showed a higher incidence of white striping and wooden breast in HF and OH chickens compared with HH chickens. In conclusion, the current study showed that both OH and HF chickens of young parent flocks had better growth performance, which could explain the higher prevalence of breast myopathies, compared with HH. The worse day-old chicken quality for OH compared with HH and HF does not seem to affect first wk mortality and later life performance.

Enriched environment housing improved the laying hen's resistance to transport stress via modulating the heat shock protective response and inflammation

An enriched environment can promote adaptability of animals to cope with complex environments. A total of 18-week-old 216 laying hens were randomly divided into 2 groups; of which, one group was housed in conventional battery cages (CC, n = 36), and the others were housed in furnished cages (FC, n = 180). At the end of 64 wk of age, 24 chickens of each group were selected for 4-hour transport treatment. The spleen tissues of laying hens were collected before transportation (BT), immediately after transportation, and at 48 h after transportation to detect the expression of the heat shock protective response signaling pathway and inflammatory factors. Serum samples were collected to detect the content of immune cytokines. Transport stress decreased heat shock proteins (HSP; including Small HSP, HSP27, HSP40, HSP60, HS70, HSP90, HSP110) in the CC group (P < 0.05), whereas there was no significant difference in the expression of HSP (except for Small HSP and HSP40) in the FC group (P > 0.05) immediately after transportation. At 48 h after transportation, mRNA levels of HSP (except for Small HSP and HSP40) in the FC group were upregulated, which were higher than those at BT (P < 0.05). The changes in HSP60, HSP70, and HSP90 protein levels had similar tendencies. The results showed that housing in furnished cages alleviated the inhibition of expression of HSP in the hens' spleen induced by transport stress. In addition, the hens housed in the FC group had lower expression levels of proinflammatory factors (nuclear transcription factor-kappa B, inducible nitric oxide synthase, cyclooxygenase-2, prostaglandin E synthase, inflammatory cytokines [IL-1β and IL-6], and tumor necrosis factor alpha) (P < 0.05). We suggest that the enriched environment can reduce transport stress damage in laying hens and improve resistance to transport stress by regulating expression of heat shock response proteins and inflammatory cytokines.

Stress Associated with Simulated Transport, Changes Serum Biochemistry, Postmortem Muscle Metabolism, and Meat Quality of Broilers

Simple Summary

The objective of this study was to investigate the effects of the transportation on broilers through the use of a vibration and motion simulation machine. Short-term transport stress induced significant physiological changes in broiler chickens. Simulation of the vibration and motion associated transport for 2 h altered hormonal secretion and blood biochemical characteristics. However, after 4 h, the birds appear to regain homeostatic equilibrium. Despite this, the stress activated antioxidant defenses, acidified muscles and increased peroxidation, as well as decreasing the meat quality of broilers. This study supports and extends previous work that identified transportation as a major risk in relation to bird welfare and meat quality.

Abstract

Many factors contribute to the stress of transporting broilers from the farm to the processing plant. Using a motion simulation machine, a total of 144 male broilers were employed to determine the effect of motion, vibration, and feed withdrawal during transportation on serum biochemical parameters, postmortem muscle metabolism, and meat quality of broilers. The results indicated that transportation did not affect the activity of lactate dehydrogenase, γ-glutamyl transferase, aspartate aminotransferase, creatine kinase, and glucose in the serum, glutathione peroxidase in the breast and thigh muscle, nitric oxide synthase (NOS) in the breast, and heat stress protein 70 mRNA expression level in the liver (p > 0.05). Serum triiodothyronine, thyroxine, and insulin concentration declined with 2 h transportation (p < 0.05) and recovered with 4 h transportation (p < 0.05). NOS concentration in the thigh increased with 2 h transportation (p < 0.05) and recovered with 4 h transportation (p < 0.05). Two-hour and 4 h transportation increased the activity of superoxide dismutase in both muscles. Malondialdehyde, lactic acid, and drip loss_{24 h} in both thigh and breast muscles increased, and glycogen in both muscles decreased with increasing transportation times (p < 0.05). Two-hour transportation did not influence pH_{45 min} and pH_{24 h} in the breast and thigh muscle, but these indexes decreased with 4 h transportation. This experiment supports and extends previous work that identified transportation as a major risk in relation to bird welfare and meat quality.

L-theanine attenuates transport stress-induced impairment of meat quality of broilers through improving muscle antioxidant status

This study was to investigate the effect of dietary L-theanine (THE) supplementation (0, 600 mg/kg) on growth performance, carcass traits, immune organ indexes, meat quality, and muscle antioxidant status of transported broilers. A total of 180 one-day-old male Ross 308 broilers were randomly allotted to 2 treatment groups including a THE-free group with 12 replicates of 10 birds each and a THE group with 6 replicates of 10 birds each. On the morning of day 42, after a 9-h fast, the birds of THE-free group were divided into 2 equal groups, and then all birds in the 3 groups were placed into 18 crates and were transported according to the following protocols: 0-h transport of birds in the THE-free group (control group), 3-h transport of birds in the THE-free group (T group), and 3-h transport of birds in the THE group (T + THE group). Results showed that dietary THE supplementation improved feed conversion ratio and birds' final body weight (P < 0.05), while transport and dietary THE supplementation did not affect carcass traits of broilers (P > 0.05). Transport increased bird live weight loss, drip loss, L*24 h, muscle malondialdehyde (MDA), protein carbonyl (PC) and lactate contents, while it decreased thymus, spleen, and bursa of Fabricius indexes, pH24h, a*, and muscle total antioxidant capacity (T-AOC), catalase (CAT), and glutathione peroxidase (GSH-PX) activities and glycogen content (P < 0.05). Nevertheless, compared with birds in the T group, birds in the T + THE group exhibited increased thymus, spleen, and bursa of Fabricius indexes, pH24h, a*24 h, and muscle T-AOC, CAT, and GSH-PX activities and glycogen content, and decreased drip loss, L*24 h, and muscle MDA, PC, and lactate contents (P < 0.05). This study provided the first evidence that dietary THE supplementation prevented transport-stress-impaired immune organ indexes and meat quality of broilers, and the reason for maintenance of meat quality by supplementation of THE may be partly ascribed to the changed muscle glycolysis metabolism and antioxidant status.

Ethanol exposure in prenatal and early postnatal induced cardiac injury in rats: involvement of oxidative stress, Hsp70, ERK 1/2, JNK, and apoptosis in a 3-month follow-up study

Alcohol exposure during pregnancy induces a wide range of structural and functional abnormalities in the fetal heart. However, the underlying mechanism of this phenomenon is not well known. This study was undertaken to elucidate probable mechanisms of myocardial damage induced by prenatal and early postnatal ethanol treatment. Pregnant Wistar rats received ethanol 4.5 g/kg BW once per day from the seventh day of gestation (GD7) throughout lactation. The oxidative stress injury of the myocardium in pups was evaluated by measuring levels of oxidative stress biomarkers. Histopathological examinations and Western blot were performed to evaluate histological features, apoptosis, and molecular alterations in the myocardial tissue of male pups on the postnatal day 21 (PN-21) and postnatal day 90 (PN-90). The results showed that maternal ethanol consumption caused oxidative stress (impaired total antioxidant capacity and malondialdehyde), histological changes, and apoptosis of the myocardium in the pups on PN-21 and PN-90. At the molecular levels, Western blot analysis revealed that ethanol modulated the protein expression of p-ERK1/2, p-JNK, and Hsp70 in the myocardial tissue of the pups after 21 and 90 days of birth compared with the controls. These findings revealed that maternal ethanol intake induced cardiac toxicity in part, mediated by oxidative stress and apoptosis in the pups. A further mechanism study revealed that ethanol enhanced ERK1/2 and JNK phosphorylation and Hsp70 protein expression.

Di-(2-ethylhexyl) phthalate (DEHP)-induced hepatotoxicity in quail (Coturnix japonica) via suppression of the heat shock response

Di-(2-ethylhexyl) phthalate (DEHP) is a widespread environmental toxicant that severely impacts agricultural production and animal and human health. Nevertheless, DEHP-induced hepatotoxicity at the molecular level in quail remains unexplored. The heat shock response (HSR), involving heat shock proteins (HSPs) and heat shock transcription factors (HSFs), is a highly conserved molecular response that is triggered by stressors, especially exposure to toxicants. To explore the DEHP-induced hepatotoxicity that occurs via regulation of HSR in birds, female quail were dosed with DEHP by oral gavage (0, 250, 500 and 1000 mg/kg) for 45 days. Based on histopathological analysis, the livers of the DEHP-treated groups exhibited structural alterations of hepatocytes, including mitochondrial swelling, derangement of hepatic plates, inflammatory cell infiltration and adipose degeneration. Ultrastructural evaluation of the livers of DEHP-treated quail revealed swollen mitochondria, partial disappearance of mitochondrial membranes and cristae, nuclear chromatin margination and nuclear condensation. The expression of HSF1 and HSF3 significantly decreased after DEHP exposure. The levels of HSPs (HSP10, HSP25, HSP27, HSP40, HSP47, HSP60, HSP70 and HSP90) were significantly downregulated in the livers of DEHP-treated quail. In this study, we concluded that DEHP exposure resulted in liver function damage and hepatotoxicity by reducing the expression of HSFs and HSPs in quail liver, which inhibited the protective effect of the HSR signaling pathway.

The role of N6-methyladenosine RNA methylation in the heat stress response of sheep (Ovis aries)

With the intensive development of the sheep industry and increasing global temperatures, heat stress in sheep has become an increasingly severe and important issue in recent years. The level of N6-methyladenosine (m6A) RNA methylation changes in response to stress plays important roles in stress responses. However, the role of m6A in the heat stress response of sheep remains unclear. To explore this issue, we measured heat stress protein (HSP) expression, liver function indexes, m6A on RNA, m6A-related enzyme expression, and tissue damage in sheep that had been subjected to heat stress. At the transcriptome level, our results showed significant increases in m6A on RNA and increased mRNA levels of HSPs (HSP70, HSP90, and HSP110) and m6A-related enzymes [METTL3 (methyltransferase-like 3), METTL14 (methyltransferase-like 14), WTAP (wilms tumor 1-associated protein), FTO (fat mass and obesity-associated protein), ALKBH5 (alkB homologue 5), YTHDF1-3 (YTH domain family proteins), and YTHDC1-2 (YTH domain-containing proteins)] following heat stress. At the protein level, the expression of METTL3, YTHDF1-2, and YTHDC2 showed no significant differences following heat stress. However, in contrast to its mRNA level after heat stress, the protein expression of YTHDF3 was reduced, while the expression of HSPs (HSP70, HSP90, and HSP110), METTL14, WTAP, FTO, ALKBH5, YTHDF3, and YTHDC1 increased in line with their measured mRNA levels. Histological experiments revealed that heat stress caused varying degrees of damage to sheep liver tissue. Moreover, immunohistochemical staining indicated that the m6A-related enzymes were expressed in sheep hepatocytes, and differences in expression patterns were observed between the control and heat stress groups. In summary, differences in the level of m6A and the expression of m6A-related enzymes in the liver of sheep were observed after heat stress. This indicates that m6A is involved in the regulation of heat stress in sheep. Our findings provide a new avenue for studying the responses to heat stress in sheep.

Di (2-ethyl hexyl) phthalate (DEHP)-induced kidney injury in quail (Coturnix japonica) via inhibiting HSF1/HSF3-dependent heat shock response

Di (2-ethyl hexyl) phthalate (DEHP) as a plasticizer can leach away from the plastic and hence entrances into the animal food chain which caused serious hazard in organs of animals, but there are few studies on DEHP kidney toxicity. The heat-shock response (HSR) consisting of the HSPs and HSFs plays an important role in various toxicity stress conditions. To investigate the influence on kidney toxicity and the modulation of HSR during DEHP exposure, female quail were fed the diet with 0, 250, 500 and 750 mg/kg DEHP by gavage administration for 45 days. The shrinkages of glomeruli and dilation of kidney tubule epithelia cells were observed in the kidney of DEHP-exposed quail. DEHP treatment could significantly decrease the expressions of HSP25, HSP27, HSP47, HSP60, while the expressions of HSP10, HSP40, HSP70, HSP90, HSP110 were upregulated in the kidney. In addition, the expression levels of HSF1 and HSF3 were significantly increased under DEHP. This is the first study to demonstrate quail exposure to DEHP is in fact detrimental to bird kidney. Besides, DEHP could attack HSR by affecting the synthesis of HSFs to mediate the transcription of the HSPs resulting in kidney damage.