The effect of early-age food restriction on heat shock protein 70 response in heat-stressed female broiler chickens

Prenatal auditory stimulation and impacts on physiological response to feed restriction in broiler chickens at market age

Feed restriction could induce physiological stress in broiler chickens, leading to welfare issues. Prenatal stimulation could improve stress-coping mechanisms in poultry. The present study aimed to elucidate the effects of subjecting developing embryos to auditory stimulation on physiological stress response to feed restriction in broiler chickens at market age. A total of 423 hatching eggs of Cobb 500 (Gallus domesticus) were subjected to the following auditory treatments: 1) no additional sound treatment other than the background sound of the incubator's compressors at 40 dB (CONTROL), 2) exposure to pre-recorded traffic noise at 90 dB (NOISE), and 3) exposure to Mozart's Sonata for Two Pianos in D Major, K 488 at 90 dB) (MUSIC). The NOISE and MUSIC treatments were for 20 min/h for 24 h (a total of 8 h/d), starting from embryonic days (ED) 12 to hatching. On d 42, an equal number of birds from each prenatal auditory stimulation (PAS) group were subjected to either ad libitum feeding (AL) or 30-h of feed restriction (FR) in a completely randomised design. The FR chickens exhibited significantly higher serum levels of corticosterone (CORT), and heat shock protein (HSP) 70 compared to those of AL. Prenatal auditory stimulation, particularly NOISE, led to lower serum levels of CORT and alpha-1-acid glycoprotein (AGP) levels compared to the CONTROL group. Additionally, NOISE significantly increased brain mRNA glucocorticoid receptor and HSP70 gene expression. The cecal population of E. coli and Lactobacillus spp. was not significantly affected by prenatal auditory stimulation. In conclusion, our findings suggest that prenatal auditory stimulation, particularly NOISE, positively impacts broiler chickens' ability to cope with feed restriction.

The beneficial effect of nanomethionine supplementation on growth performance, gene expression profile, and histopathology of heat-stressed broiler chicken

This study investigated the effects of nanomethionine (nano-meth) on performance, antioxidants, and gene expression of HSP70, HSP90 and Heat Shock factor-1 (HSF-1) from the liver, and TLR4 from the jejunum, of broiler chickens reared under normal temperatures or under heat stress. Three hundred 1-day-old chicks were randomly assigned to 5 treatment groups. Group 1 served as control. Under normal temperature, birds in group 2 received nano-meth (10 mL/L of drinking water) from d1 until the experiment ended. Group 3 birds were heat-stressed (HS) and did not receive any supplementation. Group 4 received nano-meth in the same dose from d1 old until experiment ended, and the birds were exposed to HS. Group 5 birds were HS and received supplementation of nano-meth during the HS period only. Nano-meth improved (P < 0.0001) final body weight, weight gain, feed conversion ratio, and also decreased (P < 0.0001) the effect of HS on growth performance. Reduction (P < 0.0001) in malondialdehyde and changes in antioxidant enzymes GPX and CAT activity indicated the antioxidant effect of nano-meth. Nano-meth supplementation caused an increase in the expression of HSP70 , HSP90 and HSF1, and a downregulation of TLR4 gene expression. Additionally, nano-meth-supplemented groups showed marked improvement in the histological liver structure, intestinal morphology and villus height compared to control or HS groups.

Physiological, haematological and electroencephalographic responses to heat stress in Katjang and Boer goats

The present study aimed to determine the effect of repeated heat stress on serum levels of cortisol (CORT), acute phase proteins (APP) and heat shock protein (HSP) 70, haematological indicators, and electroencephalographic (EEG) response in the native Katjang and exotic Boer goats. Six female Katjang (15.7 kg ± 0.68) and six female Boer (16.8 kg ± 1.16) goats aged 5 to 6 months old were exposed to 38 ± 1℃ for 8 h, and the procedure was repeated at three different weeks (weeks 1, 2 and 3). Measurements of rectal temperatures and EEG activity and collection of blood samples were conducted before heat exposure (0 h), immediately after the heat exposure (8 h), and 8 h after completion of heat exposure (16 h) (recovery period). The current results revealed that the Boer animals had significantly higher rectal temperatures (RT), haemoglobin (Hb) and packed cell volume (PCV) counts than their Kajang counterparts. There were significant breed × stage of heat treatment (SHT) × week of heat treatment (WHT) interactions for neutrophil to lymphocyte ratios (NLR). In general, the Katjang animals had elevated NLR compared to those of Boer. The Boer goats had reduced capacity to express serum HSP70 compared to their Katjang counterparts following the heat challenge at week 3. Boer goats demonstrated higher delta waves than the Katjang group, which suggested the former were more stressed following the heat exposure. Breed had a negligible effect on CORT, APP, WBC counts and backfat thickness. Our findings suggested that the Katjang breed, as measured by RT, HB and PCV count, and EEG activity, could be more tolerant to heat stress than Boer. The Katjang goats showed higher HSP70 expression than their Boer counterparts, suggesting improved thermoregulation in the former.

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.

Prenatal auditory stimulation induces physiological stress responses in developing embryos and newly hatched chicks

Prenatal stress may evoke considerable physiological consequences on the developing poultry embryos and neonates. The present study aimed to determine prenatal auditory stimulation effects on serum levels of ceruloplasmin (CPN), alpha-1-acid glycoprotein (AGP), corticosterone (CORT), and heat shock protein 70 (Hsp70) regulations in developing chicken embryos and newly hatched chicks. Hatching eggs were subjected to the following auditory treatments; 1) control (no additional sound treatment other than the background sound of the incubator's compressors at 40 dB), 2) noise exposure (eggs were exposed to pre-recorded traffic noise at 90 dB) (NOISE), and 3) music exposure (eggs were exposed to Mozart's Sonata for Two Pianos in D Major, K 488 at 90 dB) (MUSIC). The NOISE and MUSIC treatments were for 20 min/h for 24 h (a total of 8 h/d), starting from embryonic days (ED) 12 to hatching. The MUSIC (1.37 ± 0.1 ng/mL) and NOISE (1.49 ± 0.2 ng/mL) treatments significantly elevated CPN at ED 15 compared to the Control (0.82 ± 0.04 ng/mL) group and post-hatch day 1 (Control, 1.86 ± 0.2 ng/mL; MUSIC, 2.84 ± 0.4 ng/mL; NOISE, 3.04 ± 0.3 ng/mL), AGP at ED 15 (Control, 39.1 ± 7.1 mg/mL; MUSIC, 85.5 ± 12.9 mg/mL; NOISE, 85.4 ± 15.1 mg/mL) and post-hatch day 1 (Control, 20.4 ± 2.2 mg/mL; MUSIC, 30.5 ± 4.7 mg/mL; NOISE, 30.3 ± 1.4 mg/mL). CORT significantly increased at ED 15 in both MUSIC (9.024 ± 1.4 ng/mL) and NOISE (12.15 ± 1.6 ng/mL) compared to the Control (4.39 ± 0.7 ng/mL) group. On the other hand, MUSIC exposed embryos had significantly higher Hsp70 expression than their Control and NOISE counterparts at ED 18 (Control, 12.9 ± 1.2 ng/mL; MUSIC, 129.6 ± 26.4 ng/mL; NOISE, 13.3 ± 2.3 ng/mL) and post-hatch day 1 (Control, 15.2 ± 1.7 ng/mL; MUSIC, 195.5 ± 68.5 ng/mL; NOISE, 13.2 ± 2.7 ng/mL). In conclusion, developing chicken embryos respond to auditory stimulation by altering CPN, AGP, CORT, and Hsp70. The alterations of these analytes could be important in developing embryos and newly hatched chicks to cope with stress attributed to auditory stimulation.

Comparative genomics and selection analysis of Yeonsan Ogye black chicken with whole-genome sequencing

Yeonsan Ogye (OGYE; Gallus gallus domesticus) is a rare indigenous chicken breed that inhabits the Korean Peninsula. This breed has completely black coloring, including plumage, skin, eyes, beak, and internal organs. Despite these unique morphological characteristics, the population of OGYE has declined without in-depth research into their genome research. Therefore, this study aimed to compare the whole genome of OGYE to 12 other chicken populations, including ancestral breed, commercial breeds, Chinese indigenous breeds, and Korean native chickens. We focused on revealing the selection signature of OGYE, which has occurred through environmental pressures in the Korean Peninsula. Genome-wide selection analysis has identified local adaptation traits, such as egg development, that contribute to fetal viability and innate immune response to prevent viral and microbes infection in OGYE. In particular, SPP1 (Secreted Phosphoprotein 1), HSP90AA1 (Heat Shock Protein 90 Alpha Family Class A Member 1), and P2RX4 (Purinergic Receptor P2X 4) could have considerable involvement in egg development and RNASEL (Ribonuclease L), BRIP1 (BRCA1 Interacting Protein C-terminal Helicase 1), and TLR4 (Toll-Like Receptor 4) are crucial for the determination of the innate immune response. This study revealed the unique genetic diversity of OGYE at the genome-wide level. Furthermore, we emphasized the sustainable management of genetic resources and formulated breeding strategies for livestock on the Korean Peninsula.

Oxidative Stability, Carcass Traits, and Muscle Fatty Acid and Amino Acid Profiles in Heat-Stressed Broiler Chickens

The objective was to elucidate the effects of chronic heat stress on carcass traits, muscle oxidative stability, muscle fatty acids and amino acid profiles in broiler chickens. A total of 100-day-old male Ross broiler chicks were divided into two equal groups of five replicates. The control group (TN) was maintained on a thermoneutral condition, while the experimental group (HS) was subjected to 8 h of heat stress (34 °C). The HS group showed lower dressing percentage and breast yield compared with the TN group (p = 0.040 and 0.042, respectively). Meanwhile, heat stress significantly increased the percentage of abdominal fat in broiler chickens (p = 0.001). The HS group showed significantly lower levels of PUFA (linoleic, docosahexaenoic and eicosapentaenoic) in the breast (p = 0.003, 0.002 and 0.001, respectively) and thigh (p = 0.001, 0.009 and 0.003, respectively) muscles than did the TN group. The levels of α-lenolinec acid in the breast and thigh muscles did not differ between both experimental groups (p = 0.818 and 0.060, respectively). With exception of threonine, tyrosine and phenylalanine, the levels of essential AA in the breast muscles were significantly (p ˂ 0.05) reduced in the HS group. The HS group showed significantly higher concentration of malondialdehyde (MDA) in the breast muscles (p = 0.032). Meanwhile, the concentration of MDA in the thigh muscles did not differ between both experimental groups (p = 0.149). Furthermore, the HS group showed significantly lower superoxide dismutase and catalase in heart tissues (p = 0.005 and 0.001, respectively). In conclusion, chronic thermal stress deteriorates carcass yield and the oxidative stability of breast muscles, as well as the levels of PUFA and essential AA in broiler chickens. However, the oxidative stability of thigh muscles was not affected.

Muscle Antioxidant Activity and Meat Quality Are Altered by Supplementation of Astaxanthin in Broilers Exposed to High Temperature

This study investigated the effect of dietary astaxanthin (AST) on the meat quality, antioxidant status, and immune response of chickens exposed to heat stress. Four hundred and eighty male broilers were assigned to four treatments including AST0, AST20, AST40, and AST80 with 0, 20, 40, and 80 ppm astaxanthin supplementation levels, respectively. There was a linear decrease of malondialdehyde (MDA) in leg muscle. Catalase and superoxide dismutase levels in the plasma were linearly increased. There was a linear increase in the level of total antioxidant capacity in the leg muscle. The 3-ethylbenzothiazoline-6-sulfonate reducing activity of leg muscle was significantly increased in the AST80 treatment. The AST40 treatment showed an increase in 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity of leg muscles. Breast meat redness and yellowness were linearly increased. The astaxanthin-supplemented treatments exhibited lower drip loss and MDA concentration of leg muscle compared with the AST0 treatment at days 3 and 9 of storage. Supplementation of 40 or 80 mg/kg astaxanthin significantly decreased heat shock protein (HSP)27, HSP70, tumor necrosis factor alpha, and interleukin-6 expression in the livers. The feather corticosterone was significantly lower in the astaxanthin-supplemented treatments than in the AST0 treatment. In conclusion, astaxanthin decreased the hyperthermic stress level and improved meat quality, and antioxidant status of chickens exposed to heat stress.

Acute Heat Stress Induces the Differential Expression of Heat Shock Proteins in Different Sections of the Small Intestine of Chickens Based on Exposure Duration

In this study, we examined the protein and gene expression of heat shock proteins (HSPs) in different sections of the small intestine of chickens. In total, 300 one-day-old Ross 308 broiler chicks were randomly allocated to the control and treatment groups. The treatment group was divided into four subgroups, according to the duration of acute heat exposure (3, 6, 12, and 24 h). The influence of heat stress on the protein and gene expression of HSP70, HSP60, and HSP47 in different sections of the small intestine of chickens was determined. The protein expression of HSP70 and HSP60 was significantly higher at 6 h in the duodenum and jejunum and 12 h in the ileum. The HSP47 protein expression was significantly higher at 3 h in the duodenum and ileum and at 6 h in the jejunum. The gene expression levels of HSP70, HSP60, and HSP47 were significantly higher at the 3 h treatment group than the control group in the duodenum, jejunum, and ileum. The glutamate pyruvate transaminase and glutamate oxaloacetate transaminase levels were significantly higher at 12 and 24 h in the serum of the blood. Acute heat stress affected the expression of intestinal proteins and genes in chickens, until the induction of heat tolerance.

Evaluation of heat stress effects on cellular and transcriptional adaptation of bovine granulosa cells

Background

Heat stress is known to affect follicular dynamics, oocyte maturation, and fertilization by impairing steroidogenic ability and viability of bovine granulosa cell (bGCs). The present study explored the physiological and molecular response of bGCs to different heat stress intensities in-vitro. We exposed the primary bGCs to heat stress (HS) at 39 °C, 40 °C and 41 °C along with control samples (38 °C) for 2 h. To evaluate the impact of heat stress on bGCs, several in vitro cellular parameters including cell apoptosis, intracellular reactive oxygen species (ROS) accumulation and HSP70 kinetics were assessed by flow cytometry, florescence microscopy and western blot, respectively. Furthermore, the ELISA was performed to confirm the 17β-estradiol (E₂) and progesterone (P₄) levels. In addition, the RNA sequencing (RNA-Seq) method was used to get the molecular based response of bGCs to different heat treatments.

Results

Our findings revealed that the HS significantly decreased the cell viability, E₂ and P₄ levels in bGCs, whereas, increased the cellular apoptosis and ROS. Moreover, the RNA-Seq experiments showed that all the treatments (39 °C, 40 °C and 41 °C) significantly regulated many differentially expressed genes (DEGs) i.e. BCL2L1, STAR, CYP11A1, CASP3, SOD2, HSPA13, and MAPK8IP1 and pathways associated with heat stress, apoptosis, steroidogenesis, and oxidative stress. Conclusively, our data demonstrated that the impact of 40 °C treatment was comparatively detrimental for cell viability, apoptosis and ROS accumulation. Notably, a similar trend of gene expression was reported by RT-qPCR for RNA-seq data.

Conclusions

Our study presented a worthy strategy for the first time to characterize the cellular and transcriptomic adaptation of bGCs to heat stress (39, 40 and 41 °C) in-vitro. The results infer that these genes and pathways reported in present study could be useful candidates/indicators for heat stress research in dairy cattle. Moreover, the established model of bGCs to heat stress in the current study provides an appropriate platform to understand the mechanism of how heat-stressed bGCs can affect the quality of oocytes and developing embryo.

Cellular and Molecular Adaptation of Bovine Granulosa Cells and Oocytes under Heat Stress

Simple Summary

Heat stress can have large effects on most aspects of reproductive function in dairy cows. A hot environment can increase blood, rectal, and uterine temperatures, alter ovarian folliculogenesis, suppress fertility, oogenesis, and embryogenesis and ultimately reduce conception and pregnancy rates. Among the components of the female reproductive tract, the ovarian pool of follicles and their enclosed granulosa cells and oocytes are highly sensitive to hyperthermia. Many effects of elevated temperature on granulosa cells and developing oocytes involve increased production of reactive oxygen species, subsequently induce cellular apoptosis, and decrease the developmental ability of oocytes to be fertilized. Furthermore, heat stress-associated reproductive disorders are associated with altered progesterone and reduced estradiol production by ovarian follicles. The review mainly focuses on the follicle-enclosed granulosa cells and oocytes, provides new insights into the cellular and molecular adaptations of granulosa cells and oocyte under heat stress, depicts the role of the follicle microenvironment, and discusses some mechanisms that might underlie oocyte impairment. This study provides a possible way for the genetic adaptation to heat stress both for the regulation of body temperature and cellular resistance to elevated temperature.

Abstract

Heat stress has long been recognized as a challenging issue that severely influences the reproductive functions of dairy cattle, disrupting oocyte development during fetal growth. These detrimental effects of heat stress are the result of either the hyperthermia associated with heat stress or the physiological adjustments made by the heat-stressed animal to regulate body temperature. In addition, elevated temperatures have been implicated in increasing the production of reactive oxygen species. Thus, understanding the impact of heat stress on reproductive functions, from a cellular to molecular level, might help in selecting heat-resilient dairy cattle and developing heat stress mitigation strategies. In the present paper, we have attempted to describe the changes in the reproductive system and function of dairy cattle in response to heat stress by reviewing the latest literature in this area. The review provides useful knowledge on the cellular and genetic basis of oocyte and granulosa cells in heat-stressed dairy cattle, which could be helpful for future research in this area.

Effect of chronic heat stress on some physiological and immunological parameters in different breed of broilers

The differences in physiological and immunological parameters and pathological damage to organ tissues exposed to chronic heat stress provide the basis for evaluating heat resistance of different chicken breeds (white recessive rock [WRR] and The Lingshan [LS]). Ninety broilers of each breed were divided equally into a chronic heat stress group and a no heat stress group. The effects of chronic heat stress on the physiological and immunological parameters of broilers were analyzed using flow cytometry, ELISA, RT-qPCR, etc. Under heat stress conditions: (1) H and H/L values were significantly increased (P < 0.01) in the 2 breeds, and were higher in the WRR broilers than in the LS broilers at a late stage (P < 0.05). Although the corticosterone levels were also significantly increased (P < 0.01) in both breeds, they were lower in the 49 d WRR broilers than in the LS broilers (P < 0.01). The number of leukocytes were significantly increased in the 49 d WRR broilers (P < 0.01), whereas the number of CD3+, CD8+ cells, and erythrocytes were significantly reduced (P < 0.05). A significantly (P < 0.01) lower number of CD3+, CD4+ T-lymphocytes, and CD4+/CD8+ were present in WRR compared to that in the LS broilers. (2) The HSP70 transcript was significantly increased in the WRR broilers (P < 0.01), and was higher than the level in the LS broilers. The expression level of HSP70 protein was significantly (P < 0.05) increased in WRR broilers. (3) The WRR broilers developed cardiac and leg muscle inflammatory cellular hyperplasia and local inflammatory lesions, as well as cerebral meningitis and inflammatory hyperplasia of the brain tissue. The LS broilers developed mild cerebral inflammatory hyperplasia and mild inflammatory cellular proliferation in the leg muscle. In conclusion, under heat stress conditions, the relative physiological and immunological parameters were worse in the WRR broilers than in the LS broilers. The WRR broilers showed poor heat tolerance as evidenced from the expression of HSP70 and the extent of histopathological damages.

Impact of Heat Stress on Cellular and Transcriptional Adaptation of Mammary Epithelial Cells in Riverine Buffalo (Bubalus Bubalis)

The present study aims to identify the heat responsive genes and biological pathways in heat stressed buffalo mammary epithelial cells (MECs). The primary mammary epithelial cells of riverine buffalo were exposed to thermal stress at 42°C for one hour. The cells were subsequently allowed to recover at 37°C and harvested at different time intervals (30 min to 48 h) along with control samples (un-stressed). In order to assess the impact of heat stress in buffalo MECs, several in-vitro cellular parameters (lactate dehydrogenase activity, cell proliferation assay, cellular viability, cell death and apoptosis) and transcriptional studies were conducted. The heat stress resulted in overall decrease in cell viability and cell proliferation of MECs while induction of cellular apoptosis and necrosis. The transcriptomic profile of heat stressed MECs was generated using Agilent 44 K bovine oligonucleotide array and at cutoff criteria of ≥3-or ≤3 fold change, a total of 153 genes were observed to be upregulated while 8 genes were down regulated across all time points post heat stress. The genes that were specifically up-regulated or down-regulated were identified as heat responsive genes. The upregulated genes in heat stressed MECs belonged to heat shock family viz., HSPA6, HSPB8, DNAJB2, HSPA1A. Along with HSPs, genes like BOLA, MRPL55, PFKFB3, PSMC2, ENDODD1, ARID5A, and SENP3 were also upregulated. Microarray data revealed that the heat responsive genes belonged to different functional classes viz., chaperons; immune responsive; cell proliferation and metabolism related. Gene ontology analysis revealed enrichment of several biological processes like; cellular process, metabolic process, response to stimulus, biological regulation, immune system processes and signaling. The transcriptome analysis data was further validated by RT-qPCR studies. Several HSP (HSP40, HSP60, HSP70, HSP90, and HSPB1), apoptotic (Bax and Bcl2), immune (IL6, TNFα and NF-kβ) and oxidative stress (GPX1 and DUSP1) related genes showed differential expression profile at different time points post heat stress. The transcriptional data strongly indicated the induction of survival/apoptotic mechanism in heat stressed buffalo MECs. The overrepresented pathways across all time points were; electron transport chain, cytochrome P450, apoptosis, MAPK, FAS and stress induction of HSP regulation, delta Notch signaling, apoptosis modulation by HSP70, EGFR1 signaling, cytokines and inflammatory response, oxidative stress, TNF-alpha and NF- kB signaling pathway. The study thus identified several genes from different functional classes and biological pathways that could be termed as heat responsive in buffalo MEC. The responsiveness of buffalo MECs to heat stress in the present study clearly suggested its suitability as a model to understand the modulation of buffalo mammary gland expression signature in response to environmental heat load.

Dietary supplementation of L-glutamine and L-glutamate in broiler chicks subjected to delayed placement

This study was conducted to investigate the effect of dietary glutamine (Gln) + glutamic acid (Glu) supplementation on growth performance and physiological stress response in broiler chickens subjected to 24 h delay in placement. Equal number of day-old broiler chicks were assigned to either immediate placement or with 24 h delay in placement with no access to feed and water. Chicks from each placement group were fed either standard starter diet (control) or standard starter diet +1% AminoGut (AG; mixture of 10% Gln and 10% Glu) from 1 to 21 d. Blood and duodenal samples were collected at 21 d for analysis of serum levels of ceruloplasmin (CER), ovotransferin (OVT) and α-1 acid glycoprotein (AGP), duodenal heat shock protein (HSP) 70 expression, and villi length and crypt depth. Results showed that delayed placement for 24 h was detrimental to weight gain during the starter phase (1 to 21 d) but not thereafter. AG supplementation was not able to eliminate that reduction in weight gain and feed intake during the starter stage. However, the observed enhancement in villi length and crypt depth at d 21 resulted in improvement of FCR and weight gain during the finisher stage (22 to 42 d) and consequently the overall period (1 to 42 d). Broiler chickens supplemented with AG also showed lower mortality rate, and higher AGP, OVT, CER, and HSP 70 expression compared to their control counterparts. Based on AGP, OVT, CER, and HSP 70 expression, there is no indication that delayed placement was physiologically stressful to the broiler chickens at 21 d of age.

Environmental temperature and stocking density effects on acute phase proteins, heat shock protein 70, circulating corticosterone and performance in broiler chickens

An experiment was conducted to determine the effect of different stocking densities on serum corticosterone (CORT), ovotransferrin (OVT), α1-acid glycoprotein (AGP) and ceruloplasmin (CP) concentrations, brain heat shock protein (HSP) 70 expression and performance in broiler chickens exposed to unheated and heated conditions. Day-old chicks were stocked at 0.100 m(2)/bird (low density (LD)) or 0.063 m(2)/bird (high density (HD)), in battery cages and housed in environmentally controlled rooms. From 21 to 35 days of age, birds from each stocking density group were exposed to either 24 or 32 °C. Growth performance was recorded during the heat treatment period, and blood and brain samples were collected to determine CORT, OVT, AGP, CP and HSP 70 levels on day 35. Heat treatment but not stocking density was detrimental to growth performance. There were significant temperature × density interactions for CORT, CP and OVT on day 35. Although HD elevated CORT, CP and OVT when compared to LD, the effects of the former were more obvious under heated condition. Both temperature and density had significant effect on AGP and HSP 70. In conclusion, irrespective of temperature, high stocking density was physiologically stressful to broiler chickens, as indicated by CORT, AGP, CP, OVT and HSP 70, but not detrimental to growth performance and survivability. As it was shown in the present study, AGP, CP and OVT could be useful biomarkers to determine the effect of overcrowding and high temperature on the welfare of broiler chickens.

Cerulenin upregulates heat shock protein-70 gene expression in chicken muscle

Lines of evidence suggested that systems involved in the regulation of the stress responses and energy homeostasis are highly integrated. Because cerulenin, the natural antibiotic product of the fungus Cephalosporium ceruleans and a broad-spectrum fatty acid synthesis (FAS) inhibitor, has been shown to affect food intake and energy balance, and because the biomarker of stress Hsp-70 gene was found to interact directly with fatty acids, we hypothesized that cerulenin may regulate Hsp-70 gene expression. Therefore, the present study was undertaken to examine this issue. Cerulenin administration significantly (P < 0.05) decreased food intake and induced Hsp-70 mRNA levels in muscle, but not in liver or hypothalamus of 2-wk-old broiler chickens. These changes were accompanied by an unpregulation of muscle uncoupling protein and carnitine palmitoyltransferase 1 mRNA levels. This result indicated that the regulation of Hsp-70 gene expression in normal chickens, as estimated by oxidative stress indices [TBA reacting substances, ferric reducing/antioxidant power, and ceruloplasmin oxidase activity] levels, is tissue-specific. In attempt to discriminate between the effect of cerulenin and cerulenin-reduced food intake on Hsp-70 gene expression, we also evaluated the effect of food deprivation on the same cellular responses. Food deprivation for 16 h did not affect Hsp-70 gene expression in all tissues examined, indicating that the effect of cerulenin is independent of the inhibition of food intake. To ascertain whether the effect of cerulenin is direct or indirect, we carried out in vitro studies. Cerulenin treatment did not affect Hsp-70 gene expression in Leghorn male hepatoma and quail myoblast cell lines, suggesting that the observed effect in vivo may be mediated through the central nervous system.

Appearance of leptin-HSP70 correlation, in type 2 diabetes

In vitro and in vivo studies have shown conflicting results regarding heat shock protein (HSP) and leptin correlation. More importantly both HSP70 and leptin are correlated with C reactive proteins. The purpose of the present study was to study the correlation between serum HSP70 and leptin levels in patients with type 2 diabetes stratified according to gender. We performed a cross sectional study on the established groups of patients with type 2 diabetes defined as 1: patients with long standing diabetes for more than 3 years; and 2: patients with newly diagnosed diabetes within recent 6 months who were not on any glucose lowering treatment other than by dietary means alone and 3: healthy controls. Patients with long standing diabetes had higher HSP70, HbA1c and triglyceride than controls. Serum leptin levels were significantly lower in patients with newly diagnosed diabetes. Women with type 2 diabetes had higher leptin levels compared to men, both before and after treatment. We showed a positive correlation between leptin and HSP70 levels in women with type 2 diabetes. The correlation was strongest in women with newly diagnosed diabetes (r = 0.59) and was attenuated in women who were on treatment (r = 0.3). The significance of this correlation was only observed in women with type 2 diabetes. There was no correlation between leptin and HSP70 in men. The positive correlation between leptin and HSP is observed in chronic inflammation such as type 2 diabetes. It could be hypothesized that the observed correlation between serum HSP70 and leptin implies a higher state of chronic inflammation.

Review of human-animal interactions and their impact on animal productivity and welfare

Humans and animals are in regular and at times close contact in modern intensive farming systems. The quality of human-animal interactions can have a profound impact on the productivity and welfare of farm animals. Interactions by humans may be neutral, positive or negative in nature. Regular pleasant contact with humans may result in desirable alterations in the physiology, behaviour, health and productivity of farm animals. On the contrary, animals that were subjected to aversive human contact were highly fearful of humans and their growth and reproductive performance could be compromised. Farm animals are particularly sensitive to human stimulation that occurs early in life, while many systems of the animals are still developing. This may have long-lasting impact and could possibly modify their genetic potential. The question as to how human contact can have a positive impact on responses to stressors, and productivity is not well understood. Recent work in our laboratory suggested that pleasant human contact may alter ability to tolerate various stressors through enhanced heat shock protein (hsp) 70 expression. The induction of hsp is often associated with increased tolerance to environmental stressors and disease resistance in animals. The attitude and consequent behaviour of stockpeople affect the animals’ fear of human which eventually influence animals’ productivity and welfare. Other than attitude and behaviour, technical skills, knowledge, job motivation, commitment and job satisfaction are prerequisites for high job performance.

Changes in heat shock protein 70, blood parameters, and fear-related behavior in broiler chickens as affected by pleasant and unpleasant human contact

An experiment was conducted to determine the effects of combining both pleasant and unpleasant contacts with human beings on physiology and behavior of broiler chickens. Birds were subjected to the following treatments: (i) received no physical or visual contact with humans (control); (ii) from d 1 to 28, chicks were individually stroked gently for 30 s once daily (PL); (iii) from d 1 to 28, chicks were picked up individually, suspended by both legs, exposed to recorded noise, and swung gently for 15 s once daily (UNPL); (iv) from d 1 to 14 and from d 15 to 28, chicks were subjected to PL and UNPL, respectively (PL-UNPL); and (v) from d 1 to 14 and from d 15 to 28, chicks were subjected to UNPL and PL, respectively (UNPL-PL). On d 42, birds from each treatment group were road-transported for 3 h. Heat shock protein (hsp) 70 expression, plasma levels of corticosterone, serum creatine kinase concentration, heterophil/lymphocyte ratios (HLR), and tonic immobility duration were determined pre- and posttransit. There were significant (P < 0.05) duration of transportation × human contact treatment interactions for HLR and hsp 70 density. Following transit, the PL chicks had significantly (P < 0.05) lower HLR and greater hsp 70 density than the other groups. The corticosterone of PL and UNPL chicks were lower than their control, PL-UNPL, and UNPL-PL counterparts. The PL and PL-UNPL treatments were effective in shortening tonic immobility duration significantly (P < 0.05). Except for UNPL-PL, the serum creatine kinase activity of PL was significantly lower than the other groups. In conclusion, subjecting birds to pleasant human contact reduced stress and fear reactions to transportation by enhancing the ability to express hsp 70 in the brain. Unpleasant human contact had adverse effect on the birds' response to transportation. Early age pleasant experience with humans failed to negate the adverse effects of subsequent unpleasant contact.

Dietary supplementation of Zingiber officinale and Zingiber zerumbet to heat-stressed broiler chickens and its effect on heat shock protein 70 expression, blood parameters and body temperature

The present study was conducted to assess the effects of dietary supplementation of Zingiber officinale and Zingiber zerumbet and to heat-stressed broiler chickens on heat shock protein (HSP) 70 density, plasma corticosterone concentration (CORT), heterophil to lymphocyte ratio (HLR) and body temperature. Beginning from day 28, chicks were divided into five dietary groups: (i) basal diet (control), (ii) basal diet +1%Z. zerumbet powder (ZZ1%), (iii) basal diet +2%Z. zerumbet powder (ZZ2%), (iv) basal diet +1%Z. officinale powder (ZO1%) and (v) basal diet +2%Z. officinale powder (ZO2%). From day 35-42, heat stress was induced by exposing birds to 38±1°C and 80% RH for 2 h/day. Irrespective of diet, heat challenge elevated HSP70 expression, CORT and HLR on day 42. On day 42, following heat challenge, the ZZ1% birds showed lower body temperatures than those of control, ZO1% and ZO2%. Neither CORT nor HLR was significantly affected by diet. The ZO2% and ZZ2% diets enhanced HSP70 expression when compared to the control groups. We concluded that dietary supplementation of Z. officinale and Z. zerumbet powder may induce HSP70 reaction in broiler chickens exposed to heat stress.

Changes in heat shock protein 70 expression and blood characteristics in transported broiler chickens as affected by housing and early age feed restriction

An experiment was conducted to determine the effects of 2 types of housing systems and early age feed restriction on heat shock protein (hsp) 70 expression and blood parameters in broiler chickens subjected to road transportation. On d 1, female chicks were housed either in windowless environmentally controlled chambers (temperature was set at 32 degrees C on d 1 and gradually reduced to 23 degrees C by d 21; CH) or in conventional open-sided houses (OH) with cyclic temperatures (minimum, 24 degrees C; maximum, 34 degrees C). Equal number of chicks from each housing system were subjected to either ad libitum feeding or 60% feed restriction on d 4, 5, and 6 (FR). On d 42, all of the birds were crated and transported for 6 h. Birds raised in OH had smaller increases in heterophil:lymphocyte ratios and plasma corticosterone concentrations than those of CH. Subjecting birds to FR dampened heterophil:lymphocyte ratios and corticosterone reactions to transportation. After 4 h of transportation, the OH birds had greater hsp 70 expression than their CH counterparts. Within the CH, the FR chicks showed higher hsp 70 density than those of the ad libitum-fed group. Except for glucose, housing system had a negligible effect on serum levels of cholesterol, potassium, and chloride. Collectively, the results suggest that the improved tolerance to transport stress in OH and FR chicks could be associated with better hsp 70 expression.

The effects of vitamin C and E supplementation on heat shock protein 70 response of ovary and brain in heat-stressed quail

1. The effects of vitamin C (L-ascorbic acid) and vitamin E (alpha-tocopherol acetate) supplementation on egg production and heat shock protein 70 (Hsp70) response of ovary and brain in the Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature were evaluated. 2. The birds (n = 540; 55 d old) were randomly assigned to 18 groups consisting of 3 replicates of 10 birds each in a 2 x 3 x 3 factorial arrangement of treatments. Birds were kept in wire cages in a temperature-controlled room at either 22 degrees C (thermo-neutral, TN) or 34 degrees C (heat stress, HS) for 8 h/d (09:00 to 17:00 h; until the end of the study) and fed on a basal diet or the basal diet supplemented with either three levels of vitamin C (0, 250 and 500 mg of L-ascorbic acid/kg of diet) or three levels of vitamin E (0, 250 and 500 mg of dl-alpha-tocopheryl acetate/kg of diet). 3. Feed intake and egg production were not affected by vitamin C and E supplementation under thermo-neutral conditions. However, feed intake and egg production were increased with the vitamin C or E supplementation either singly or in combination in heat-stressed quail. When vitamin was added, feed intake and egg production of quails under TN were different from those raised under HS. However, in the absence of supplemental vitamins, feed intake and egg production at TN and HS were no different. 4. Heat exposure increased serum corticosterone levels and Hsp70 expression. Serum corticosterone level was significantly decreased by vitamin C or E supplementation in HS groups for quail. Ovary and brain Hsp70 expression linearly decreased as dietary vitamin C or vitamin E supplementation increased in heat-stressed groups. However, Hsp70 expression of ovary and brain was not affected by vitamin C or E supplementation under thermo-neutral conditions. 5. The present study showed that a combination of dietary vitamin C (500 mg) and E supplementation (500 mg) may alleviate some heat stress effects of heat shock proteins of ovary and brain and egg production of Japanese quail.

Crating and heat stress influence blood parameters and heat shock protein 70 expression in broiler chickens showing short or long tonic immobility reactions

Two hundred thirty-five 1-d-old broiler chickens showing short or long tonic immobility responses were classified as low fear (LF) or high fear (HF) responders, respectively. On d 41, they were subjected to either crating or heat challenge (34 +/- 1 degrees C) for 3 h and its effect on plasma corticosterone concentration, heterophil/lymphocyte ratios, and heat shock protein (HSP) 70 expression in brain tissue were determined. Crating and heat exposure elevated heterophil/lymphocyte ratios in both LF and HF birds. Circulating corticosterone, however, was greater in HF than LF birds after crating and heat challenge. Although differences between fear responder group for HSP 70 were negligible before heat challenge, after 3 h of heat exposure, the response was greater for the HF than the LF group. Both LF and HF showed similar increases in HSP 70 after crating.

Leptin downregulates heat shock protein-70 (HSP-70) gene expression in chicken liver and hypothalamus

Heat shock protein (HSP)-70 is expressed in normal and stressed cells but is highly stress-inducible. Although leptin has long been suggested to be involved in the regulation of stress response, its interaction with the HSP-70 gene is still unknown, under both unstressed and stressed conditions. The present study has aimed to investigate the effect of leptin on HSP-70 gene expression in normal chicken liver, hypothalamus, and muscle. Continuous infusion of recombinant chicken leptin (8 mug/kg per hour) at a constant rate of 3 ml/h for 6 h in 3-week-old broiler chickens significantly (P < 0.05) decreased food intake and HSP-70 mRNA levels in liver and hypothalamus, but not in muscle. In an attempt to discriminate between the effect of leptin and of leptin-reduced food intake on HSP-70 gene expression, we also evaluated the effect of food deprivation on the same cellular responses in two broiler chicken lines genetically selected for low (LL) or high (FL) abdominal fat pad size. Food deprivation for 16 h did not affect HSP-70 gene expression in any of the studied tissues indicating that the effect of leptin was independent of the inhibition of food intake. Regardless of the nutritional status, HSP-70 mRNA levels were significantly (P < 0.05) higher in the hypothalamus of FL compared with LL chickens consistent with higher mRNA levels for hypothalamic corticotropin-releasing factor. To assess, whether the effects of leptin were direct or indirect, we carried out in vitro studies. Leptin treatments did not affect HSP-70 mRNA levels in a leghorn male hepatoma cell line or quail myoblast cell line suggesting that the effect of leptin on HSP-70 gene expression is mediated through the central nervous system. Furthermore, HSP-70 gene expression was gender-dependent with significantly (P < 0.05) higher levels in male than in female chickens.

Effects of early age feed restriction and heat conditioning on heat shock protein 70 expression, resistance to infectious bursal disease, and growth in male broiler chickens subjected to heat stress

The effects of early age feed restriction and heat conditioning on heat shock protein (HSP) 70 expression, antibody production, resistance to infectious bursal disease (IBD), and growth of heat-stressed male broiler chickens were investigated. Chicks were divided into 4 groups: 60% feed restriction on d 4,5, and 6 (FR); exposure to 36 +/- 1 degrees C for 1 h from d 1 to 21 (HT); combination of FR and HT (FRHT); and control. From d 35 to 50, heat stress was induced by exposing birds to 38 +/- 1 degrees C and 80% RH for 2 h/d. On d 36, each bird was administered 10 times the normal dose of live IBD vaccine. After heat exposure, the FRHT birds had higher HSP 70 density (d 41) and weight gain (from d 35 to 49) and lower bursal histological score (BHS) (d 51) than their HT and control counterparts. The HSP 70 expression and BHS of FR birds were not significantly different from those of the other 3 groups during the heat exposure period. Heat shock protein 70 and BHS data were negatively correlated (r = -0.33, P = 0.0008). We concluded that FRHT could improve weight gain and resistance to IBD in male broiler chickens under heat stress conditions. The improved heat tolerance and disease resistance in FRHT birds could be attributed to better HSP 70 response.