Thermoneutral Group Research Articles

Impacts on performance of growing-finishing pigs under heat stress conditions: a meta-analysis.

High ambient temperatures are a challenge for animal production around the world, and they are one of the major reasons for economic and productive losses in pig production. Under stress conditions, the energy contribution to productive functions is reduced, generating health imbalances, decreased productivity rates and changes in animal behavior. Despite the numerous articles published on this subject, the variability of results on performance parameters is high. For this reason, the objective of the present study was to evaluate the actual impact of high ambient temperature (HAT) (29°C to 35°C) on growing-finishing pig performance, compared with animals kept in a thermoneutral environment (TNT) (18°C to 25°C), based on meta-analysis. Data on average daily gain (ADG), average daily feed intake (FI) and feed gain ratio (F:G) were extracted from 22 (n = 22) papers published in scientific journals. The values were analyzed using an expansion of the t-test, considering the random effect of each study. Results showed that HAT reduced the values of ADG (654.38 vs 595.81g/d) and FI (2.141 vs 1.875g/d) when compared with the thermoneutral group. There was no statistical difference between the F:G values for both groups. In conclusion, high ambient temperatures negatively influence performance parameters of growing-finishing pigs when compared with those in thermoneutral conditions.

174 Follicular fluid extracellular vesicles obtained from Holstein cows kept under thermoneutral or heat stress conditions modify gene expression of in vitro-matured oocytes

Heat stress (HS) has a massive impact on bovine reproduction. In cows, some of these deleterious effects involve follicular development and oocyte quality. Extracellular vesicles (EV) secreted by granulosa cells play a critical role in the intrafollicular environment by directly influencing cumulus cells and oocyte functions. The objective of this study was to investigate the effect of follicular fluid EV obtained from Holstein cows kept under thermoneutral (TN) or HS conditions, on in vitro bovine oocyte maturation. Non-lactating Holstein cows were synchronized with the Ovsynch protocol and also received an intravaginal progesterone device. From ovulation day (Day 1), cows were randomly assigned to TN (26°C, 73% humidity; n=12) or HS (36°C, 70% humidity; n=12) environments. On Day 9, 2 follicles (F1 and F2) were individually aspirated and all remained follicles were ablated. Then, on Day 14, newly formed F1 and F2 were also aspirated. Follicular fluid from all follicles from each treatment was pooled and EV were obtained according to Silveira et al. (2017 PLoS One 12, 1-25) and diluted in PBS (100μL of PBS per mL of follicular fluid centrifuged). Pools of 20 cumulus-oocyte complexes (COC) grade 1 or 2 (Stojkovic et al. Biol Reprod 200164, 904-992], predominantly from Bos indicus, were submitted to the following treatment groups: Control (n=4): matured in 90μL of TCM-199 with Eagles’ salts, glutamine, NaHCO3, pyruvate, amikacin, and FSH (base medium); TN (n=4): matured in 81μL of base medium+9μL of TN EV suspension; and HS (n=4): matured in 81μL+9μL of HS EV suspension. All treatments were carried out at 38.5°C for 24h in a humid atmosphere with 5% CO2. After 24h of maturation, COC were evaluated for meiotic progression (Hoechst 33342 stain), DNA integrity (TUNEL stain), and expression of genes related to oocyte quality (TaqMan assay, Applied Biosystems/Thermo Fisher Scientific, Waltham, MA, USA). Results were analysed using ANOVA followed by Tukey post hoc test (P<0.05). When the experimental groups were compared with the control group, there was no treatment effect on meiotic progression, DNA integrity, or gene expression of cumulus cells. In the oocytes of the TN group, the genes HSF1, IGFBP2, BMP15, GDF9, CDCA8, HAS2, RPL15, STAT3,and PFKP were less expressed. We concluded that oocytes matured in the presence of EV from follicular fluid of cows kept under TN conditions had lesser expression of genes related to oocyte quality. This study was supported by FAPESP (Grant #2012/18297-7) and CAPES Foundation of Brazil.

Impact of strain and duration of thermal stress on carcass yield, metabolic hormones, immunological indices and the expression of HSP90 and Myogenin genes in broilers

The aim was to elucidate the effects of strain and the duration of thermal stress (36 °C) on the carcass yield, metabolic hormones, immunological parameters and the relative expression of liver heat shock protein 90 (HSP90) and Myogenin genes. Two hundred and seventy day-old chicks (135 of each breed; Ross 308 and Cobb 500) were used in this trial. The birds were divided into 3 equal groups (CON: thermoneutral condition; S1 and S2 groups were subjected to 4 and 6 h of daily thermal stress, respectively. The relative bursa weight in the thermonuteral Ross broilers, but not Cobb broilers was significantly greater than both heat-stressed groups (P = 0.001). The serum Na and phosphorus levels were significantly decreased when both broiler strains subjected to 6 h of thermals stress (P = 0.020 and 0.022, respectively). A linear decrease in the serum T3 level was recorded in both broiler strains as the duration of thermal stress increases (P = 0.001). In both broiler strains, heat stress up-regulate the expression of liver HSP90 gene compared with the thermoneutral group (P = 0.012). Meanwhile, the S2 group of Ross broilers showed a significantly lower IgG level (P = 0.027). Moreover, thermal stress for 6 h down-regulate the relative expression of Myogenin gene compared with the S1 and thermoneutral groups (P = 0.005). In conclusion, thermal stress for 6 h down-regulate the mRNA expression of liver Myogenin, concomitantly with an increase in the expression of HSP90 gene in both broiler strains. These results could be helpful in the markers assisted selection to develop more heat-tolerant broiler strains.

N-Acetyl cysteine improves performance, reproduction, antioxidant status, immunity and maternal antibody transmission in breeder Japanese quail under heat stress condition

This study was conducted to evaluate the effects of N-Acetyl cysteine (NAC) supplementation on the productive and reproductive performance, antioxidant status and immune response in breeder quails reared under heat stress (HS). A total of 100 breeder quails were divided into four groups. One group was kept in an environmentally controlled room (22 °C) and considered as thermoneutral (TN) and three groups were kept at the 34 °C and fed with either a basal diet or the basal diet supplemented with 2.5 or 5 g/kg NAC. Heat stress decreased performance in birds fed the basal diet (P < 0.05) compared with the TN group. Higher feed intake (P < 0.05) and egg production (P < 0.05), improved feed efficiency (P < 0.05), haugh unit and hatchability variables (P < 0.05) occurred in NAC supplemented groups compared with the group reared under HS. Birds receiving NAC under HS had higher maternal serum IgG and egg yolk IgY indicating that the NAC in the diets improved the immune response of birds. Quails receiving the NAC diets exhibited higher (P < 0.05) plasma and liver activities of superoxide dismutase, catalase and glutathione peroxidase as well as lower (P < 0.05) plasma and liver levels of malondialdehyde compared with the HS group fed the basal diet. In addition, dietary supplementation with NAC increased (P < 0.05) the titers of antibodies for both primary and secondary injections in quails exposed to HS and elevated the antibody titer against SRBC to a level similar to that of quails under TN condition. Supplementation of the diet with NAC increased (P < 0.05) stimulation indices 24 and 36 h after the injection of phytohaemagglutinin compared with the basal group exposed to HS. All breeder quails receiving the NAC supplement had lower (P < 0.05) heterophil and H/L ratios as well as higher (P < 0.05) lymphocytes than quails fed the basal diet under the same stress conditions. All quails receiving NAC in the diet had lower (P < 0.05) plasma levels of triglycerides, total cholesterol, and LDL-cholesterol as well as higher (P < 0.05) plasma levels of HDL-cholesterol compared with the quails fed the basal diet and exposed to the same HS conditions. It could be concluded from this trial that, quails receiving NAC under HS exhibited egg production, egg quality, reproductive performance, antioxidant status and immune response similar to quails exposed to TN condition. Our results suggest that dietary supplementation with NAC could improve the performance of quails by reducing the negative effects of HS and could thus be considered to be a new nutritional strategy for the alleviation of the adverse effects of HS.

Effects of chronic thermal stress on growth performance, carcass traits, antioxidant indices and the expression of HSP70, growth hormone and superoxide dismutase genes in two broiler strains

The objective was to investigate the effects of genetic type and the duration of chronic thermal stress (36 °C) on the growing efficiency, carcass traits, antioxidant status, and the expression of liver heat shock protein 70 (HSP70), growth hormone (GH) and superoxide dismutase (SOD) genes. Two hundred and seventy one-day-old chicks (135 male chicks of each breed; Ross 308 and Cobb 500) were used in this work. On the 21st day of age, birds were allocated randomly into 3 equal groups till the 42 days of age (CON:raised in a thermoneutral condition; HS1 and HS2 groups were subjected to 4 and 6 h of daily thermal stress, respectively). Regardless of genetic type, thermal stress decreased the dressing percentage in broilers when compared with the thermoneutral conditions (p = 0.039). In both broiler strains, thermal stress for 6 h (HS2) increased the heterophil to lymphocyte ratio (p = 0.036) and the serum albumin, cholesterol and triglyceride levels (p = 0.023, 0.012 and 0.005, respectively) compared with the thermoneutral group. Under the thermonuteral and heat stress conditions, the Ross broiler chickens showed a significant lower serum triiodothyronine level compared with the Cobb boilers (p = 0.042). It is interesting to note that the expression of HSP70 in the liver of heat-stressed Ross broilers, either 4 or 6 h, was significantly (p = 0.002) higher than that reported in the heat-stressed Cobb broilers. In both broiler strains, the thermal stress for 6 h up-regulate the expression of SOD gene (p = 0.001), but down-regulate the expression of GH gene (p = 0.021) when compared with the CON group. In conclusion, chronic thermal stress down-regulate the mRNA expression of liver GH, concomitantly with an increase in the expression of HSP70 and SOD genes in both broiler strains. This could be useful in the identification of molecular genetic markers to assist in selecting broilers that are more tolerant to heat stress.

Supplementation of Bacillus subtilis-based probiotic reduces heat stress-related behaviors and inflammatory response in broiler chickens.

Probiotics reduce stress-related inflammation and abnormal behaviors in humans and rodents via regulation of the microbiota-gut-brain axis. The objective of this study was to determine if probiotic, Bacillus subtilis, has similar functions in broiler chickens under heat stress (HS). Two hundred forty 1-d-old broiler chicks were assigned to 48 pens with 4 treatments: Thermoneutral (TN)-RD (regular diet), TN-PD (the regular diet mixed with 1 × 106 CFU/g feed probiotic), HS-RD and HS-PD. Probiotic (Sporulin) was fed from day 1; and HS at 32°C for 10 h daily was initiated at day 15. The data showed that final BW, average daily gain , and feed conversion efficiency were improved in PD groups as compared to RD groups regardless of the ambient temperature (P < 0.01). Heterophil to lymphocyte ratio was affected by treatment and its value was in the order of HS-RD > HS-PD > TN-RD > TN-PD birds (P < 0.01). Compared to TN birds, HS birds spent more time in wing spreading, panting, squatting close to the ground, drinking, sleeping, dozing, and sitting but spent less time in eating, standing, and walking (P < 0.05 or 0.01). In addition, HS birds had greater levels of hepatic IL-6, IL-10, heat shock protein (HSP)70, and HSP70 mRNA expression (P < 0.01) and greater levels of cecal IgA and IgY (P < 0.01) compared to TN birds. Within TN groups, TN-PD birds had greater concentrations of hepatic IL-10 (P < 0.05) and cecal IgA (P < 0.01) than TN-RD birds. Within HS groups, HS-PD birds spent less time in wing spreading, panting, squatting close to the ground, drinking, sleeping, dozing, and sitting but spent more time in eating, foraging, standing, and walking than HS-RD birds (P < 0.05 or 0.01). The HS-PD birds also had lower concentrations of hepatic IL-6 and HSP70 (P < 0.01), whereas greater levels of IL-10 (P < 0.05) and lower concentrations of cecal IgA and IgY (P < 0.01). These results indicate that broilers fed the probiotic, B. subtilis, are able to cope with HS more effectively by ameliorating heat-induced behavioral and inflammatory reactions through regulation of microbiota-modulated immunity.

Effect of epigallocatechin gallate on growth performance and serum biochemical metabolites in heat-stressed broilers

This study aims to investigate the effects of epigallocatechin gallate (EGCG) on the growth performance and serum metabolic characteristics of heat-stressed broilers. A total of 192 14-day-old Arbor Acres broilers were divided into 4 groups with 6 replicates per group (8 chickens/cage). Thermoneutral group (Group TN) was fed the basal diet and maintained at 28°C for 24 h/d. The heat-stressed groups were housed at 35°C for 12 h/d and 28°C for 12 h/d and fed the basal diet supplemented with EGCG at 0, 300, and 600 mg/kg diet (Groups HS0, HS300, and HS600, respectively). The production performance and serum metabolic characteristics were analyzed at d 21, 28, and 35, respectively. At d 35 of age, heat stress reduced (P < 0.05) the body weight (BW), feed intake (FI) and the contents of serum total protein (TP) and glucose (GLU); inhibited (P < 0.05) alkaline phosphatase (ALP) activity; But increased (P < 0.05) the contents of uric acid (UA), cholesterol (CHOL), triglyceride (TG), and the activities of creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST). Heat-stressed chickens fed EGCG exhibited a linear increase (P < 0.05) in BW, FI, the levels of serum TP, GLU, and ALP activity; and linear decrease (P < 0.05) in the contents of serum UA, CHOL, and TG, as well as the activities of LDH, CK, and AST. Heat stress also reduced (P < 0.05) the activities of serum glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) on d 35 and increased (P < 0.05) the GSH-Px and SOD activity on d 21 and malondialdehyde (MDA) contents. There was a linear increase (P < 0.05) in activities of GSH-Px, SOD and CAT at 35 d of age, and linear decreased (P < 0.05) in MDA contents. In conclusion, EGCG can improve the growth performance of broilers by enhancing antioxidant property and alleviating oxidant damage caused by heat stress.

Organic chromium modifies the expression of orexin and glucose transporters of ovarian in heat-stressed laying hens.

In this study, the effect of the supplemental organic chromium (Cr) forms on the expression of ovarian orexin(hypocretin), glucose transporters (GLUTs), heat shock proteins (HSPs) andnuclear factor-kappaB (NF-κB)were investigated in laying hens (HS). Laying hens (n=1800; 16-wk-old; Lohmann LSL-Lite) were allocated to 6 random groups according to a 2 × 3 factorial trial scheme with two different environmental temperatures [Thermoneutral (TN groups; at either 22±2 °C 24 h/d) and heat stress (HS groups; at 34±2 °C for 8 h/d, 08:00 to 17:00 h, followed by 22°C for 16 h for a period of 12 wks)], andhens reared under both environmental conditions were fed either a basal diet or the basal diet supplemented with 1.600 mg of chromium-picolinate (CrPic, 12.43% Cr) and 0.788 mg of chromium-histidinate (CrHis, 25.22% Cr) per kg of diet, delivering 200 µg elemental Cr per kg diet. HS groups showed decreased levels of orexin and GLUTs(GLUT1, GLUT4), and increased NFκB, HSP60, HSP70 and HSP90 levels compared to the TN groups in ovarian tissue of hens (P &lt; 0.0001 for all).However, dietary chromium supplementation (CrPic-CrHis) increasedorexin and GLUTs levels and significantly reduced the NF-κB and HSPs levels making them closer to those of thermoneutral group (P &lt; 0.0001).In conclusion, CrPic and CrHis showed supported the relief and treatment of stress complications.

Enhancing Tolerance of Broiler Chickens to Heat Stress by Supplementation with Vitamin E, Vitamin C and/or Probiotics

Abstract Heat stress is one of the major challenges which the poultry industry faces during summer in tropical and subtropical regions. This study was conducted to evaluate the impact of Vitamin (Vit) E, C and/or probiotics on improving tolerance of broiler chickens to chronic heat stress (CHS). A total of 294, 1-day-old Cobb-500 broiler chicks were allocated into seven treatment groups; Thermoneutral group was raised under a thermoneutral condition during 25–42 d of age. The other six groups were raised for three successive days per week at 36±2ºC and 75–85% relative humidity for 7 h daily: heat stressed group, Vit E (100 mg/kg diet), Vit C (200 mg/kg diet), Vit C+Vit E, probiotics (Saccharomyces cerevisiae and Lactobacillus acidophilus at 2 g/kg diet) and Vit C+Vit E+probiotics. Exposure to CHS decreased body weight gain (BWG), feed intake (FI), and abdominal fat. It had adverse impact on feed conversion ratio (FCR), packed cell volume (PCV), monocyte, basophil, total protein, and phagocytic activity while increased plasma cholesterol and aspartate aminotransferase (AST) compared to the thermoneutral group. Vit E, Vit C or probiotics alone decreased the adverse effects of CHS on growth rate throughout the experimental period. Vit C and E were equally potent during the experimental period, but were less effective than the combination of both vitamins. Vit E increased the dressing percentage and abdominal fat as compared to the thermoneutral group, but decreased AST while increasing basophil, monocyte and globulin compared to the heat stressed group. In addition, serum albumin and AST of Vit E were lower compared to Vit C, but cholesterol was higher. Vit E increased red blood cells and white blood cells, but plasma cholesterol was increased compared with the heat stressed group. Vit C increased PCV, lymphocytes, monocyte, basophil and albumin and decreased neutrophil. Both vitamins without/with probiotic induced a further increase in basophil, serum total protein, and albumin. It could be concluded that supplementation of Vit E, Vit C, probiotics, and different combinations reduced some of the adverse effects of CHS, and Vit E+Vit C+probiotics was the most effective for economic traits followed by Vit E+Vit C or probiotics.

Effect of epigallocatechin gallate on growth performance and antioxidant capacity in heat-stressed broilers

ABSTRACTThis study investigated the effects of epigallocatechin gallate (EGCG) on the growth performance and antioxidant capacity of 35-d-old broilers exposed to heat stress. Broilers, 14 d of age, were divided into four groups with six replicates per group (eight chickens/replicate). Thermoneutral group (Group TN) was fed the basal diet and maintained at 28°C for 24 h/d. The heat-stressed groups were housed at 35°C for 12 h/d and 28°C for 12 h/d and fed the basal diet supplemented with EGCG at 0, 300 and 600 mg/kg diet (Groups HS0, HS 300 and HS600, respectively). Compared with Group TN, heat-stressed groups showed significantly reduced gain, feed intake and serum total protein and glucose levels; inhibited serum alkaline phosphatase activities; and increased serum levels of uric acid, cholesterol and triglycerides and the activity of serum creatine kinase, lactate dehydrogenase and aspartate aminotransferase (p < 0.05). Compared with Group HS0, Group HS600 exhibited an increased gain and feed intake; and normalised blood parameters and enzyme activities. Compared with Group TN, the expression of antioxidant-related liver proteins was decreased in Group HS0 and increased in Groups HS300 and HS600 (p < 0.05). The results suggest that EGCG can improve the growth performance and alleviate the oxidant damage by modulating the antioxidant properties of broilers.

Transcriptome analysis reveals potential mechanisms underlying differential heart development in fast- and slow-growing broilers under heat stress

BackgroundModern fast-growing broilers are susceptible to heart failure under heat stress because their relatively small hearts cannot meet increased need of blood pumping. To improve the cardiac tolerance to heat stress in modern broilers through breeding, we need to find the important genes and pathways that contribute to imbalanced cardiac development and frequent occurrence of heat-related heart dysfunction. Two broiler lines – Ross 708 and Illinois – were included in this study as a fast-growing model and a slow-growing model respectively. Each broiler line was separated to two groups at 21 days posthatch. One group was subjected to heat stress treatment in the range of 35–37 °C for 8 h per day, and the other was kept in thermoneutral condition. Body and heart weights were measured at 42 days posthatch, and gene expression in left ventricles were compared between treatments and broiler lines through RNA-seq analysis.ResultsBody weight and normalized heart weight were significantly reduced by heat stress only in Ross broilers. RNA-seq results of 44 genes were validated using Biomark assay. A total of 325 differentially expressed (DE) genes were detected between heat stress and thermoneutral in Ross 708 birds, but only 3 in Illinois broilers. Ingenuity pathway analysis (IPA) predicted dramatic changes in multiple cellular activities especially downregulation of cell cycle. Comparison between two lines showed that cell cycle activity is higher in Ross than Illinois in thermoneutral condition but is decreased under heat stress. Among the significant pathways (P < 0.01) listed for different comparisons, “Mitotic Roles of Polo-like Kinases” is always ranked first.ConclusionsThe increased susceptibility of modern broilers to cardiac dysfunction under heat stress compared to slow-growing broilers could be due to diminished heart capacity related to reduction in relative heart size. The smaller relative heart size in Ross heat stress group than in Ross thermoneutral group is suggested by the transcriptome analysis to be caused by decreased cell cycle activity and increased apoptosis. The DE genes in RNA-seq analysis and significant pathways in IPA provides potential targets for breeding of heat-tolerant broilers with optimized heart function.

The effect of local skin cooling before a sustained, submaximal isometric contraction on fatigue and isometric quadriceps femoris performance: A randomized controlled trial

The central- and peripheral mechanisms by which heat strain limits physical performance are not fully elucidated. Nevertheless, pre-cooling is often used in an attempt to improve subsequent performance. This study compared the effects of pre-cooling vs. a pre-thermoneutral application on central- and peripheral fatigue during 60% of isometric maximum voluntary contraction (MVC) of the right quadriceps femoris muscle. Furthermore, the effects between a pre-cooling and a pre-thermoneutral application on isometric MVC of the right quadriceps femoris muscle and subjective ratings of perceived exertion (RPE) were investigated. In this randomized controlled trial, 18 healthy adults voluntarily participated. The participants received either a cold (experimental) application (+8°C) or a thermoneutral (control) application (+32°C) for 20min on their right thigh (one cuff). After the application, central (fractal dimension – FD) and peripheral (muscle fiber conduction velocity – CV) fatigue was estimated using sEMG parameters during 60% of isometric MVC. Surface EMG signals were detected from the vastus medialis and lateralis using bidimensional arrays. Immediately after the submaximal contraction, isometric MVC and RPE were assessed. Participants receiving the cold application were able to maintain a 60% isometric MVC significantly longer when compared to the thermoneutral group (mean time: 78 vs. 46s; p=0.04). The thermoneutral application had no significant impact on central fatigue (p>0.05) compared to the cold application (p=0.03). However, signs of peripheral fatigue were significantly higher in the cold group compared to the thermoneutral group (p=0.008). Pre-cooling had no effect on isometric MVC of the right quadriceps muscle and ratings of perceived exertion. Pre-cooling attenuated central fatigue and led to significantly longer submaximal contraction times compared to the pre-thermoneutral application. These findings support the use of pre-cooling procedures prior to submaximal exercises of the quadriceps muscle compared to pre-thermoneutral applications.

The effect of local cryotherapy on subjective and objective recovery characteristics following an exhaustive jump protocol.

The purpose of this controlled trial was to investigate the effects of a single local cryotherapy session on the recovery characteristics over a period of 72 hours. Twenty-two young and healthy female (n=17; mean age: 21.9±1.1 years) and male (n=5;mean age: 25.4±2.8 years) adults participated in this study. Following an exhaustive jump protocol (3×30 countermovement jumps), half of the participants received either a single local cryotherapy application (+8°C) or a single local thermoneutral application (+32°C) of 20-minute duration using two thigh cuffs. Subjective measures of recovery (delayed-onset muscle soreness and ratings of perceived exertion) and objective measures of recovery (vertical jump performance and peak power output) were assessed immediately following the postexercise applications (0 hours) and at 24 hours, 48 hours, and 72 hours after the jump protocol. Local cryotherapy failed to significantly affect any subjective recovery variable during the 72-hour recovery period (P>0.05). After 72 hours, the ratings of perceived exertion were significantly lower in the thermoneutral group compared to that in the cryotherapy group (P=0.002). No significant differences were observed between the cryotherapy and the thermoneutral groups with respect to any of the objective recovery variables. In this experimental study, a 20-minute cryotherapy cuff application failed to demonstrate a positive effect on any objective measures of recovery. The effects of local thermoneutral application on subjective recovery characteristics were superior when compared to the effects of local cryotherapy application at 72 hours postapplication.

Segmentation and characterization of interscapular brown adipose tissue in rats by multi-parametric magnetic resonance imaging.

The aim was to auto-segment and characterize brown adipose, white adipose and muscle tissues in rats by multi-parametric magnetic resonance imaging with validation by histology and UCP1. Male Wistar rats were randomized into two groups for thermoneutral (n = 8) and cold exposure (n = 8) interventions, and quantitative MRI was performed longitudinally at 7 and 11 weeks. Prior to imaging, rats were maintained at either thermoneutral body temperature (36 ± 0.5 °C), or short term cold exposure (26 ± 0.5 °C). Neural network based automatic segmentation was performed on multi-parametric images including fat fraction, T2 and T2* maps. Isolated tissues were subjected to histology and UCP1 analysis. Multi-parametric approach showed precise delineation of the interscapular brown adipose tissue (iBAT), white adipose tissue (WAT) and muscle regions. Neural network based segmentation results were compared with manually drawn regions of interest, and showed 96.6 and 97.1% accuracy for WAT and BAT respectively. Longitudinal assessment of the iBAT volumes showed a reduction at 11 weeks of age compared to 7 weeks. The cold exposed group showed increased iBAT volume compared to thermoneutral group at both 7 and 11 weeks. Histology and UCP1 expression analysis supported our imaging results. Multi-parametric MR based neural network auto-segmentation provides accurate separation of BAT, WAT and muscle tissues in the interscapular region. The cold exposure improves the classification and quantification of heterogeneous BAT.

Impact of temperature-humidity index on egg-laying characteristics and related stress and immunity parameters of Japanese quails.

The aim of this study was to investigate the effect of temperature-humidity index (THI) level on productive parameters, welfare, and immunity in Japanese quails. One hundred and eighty (180) birds of Japanese quail, 14weeks old, were used. Birds were divided randomly into three equal groups, control (at low THI, less than 70), H1 (at moderate THI, 70-75), and H2 (at high THI, 76-80). Birds in the control group had higher body weight (281.2g, p = 0.001), egg mass (745g, p = 0.001), fertility (85.4%, p = 0.039), hatchability (80.4%, p = 0.001), and immune response titer to Newcastle disease virus (p = 0.031), compared with H2 group. Furthermore, the thermoneutral group had higher internal egg quality score [albumen height (5.14mm, p = 0.001), yolk height (10.88mm, p = 0.015), yolk index (42.32%, p = 0.039), and Haugh unit (92.67, p = 0.001)]. Nevertheless, there were no significant differences in fertility percentage, immune response, and corticosterone concentration between control and H1 group. Birds in the H2 group had the lowest total leucocytic count and lymphocyte percentage (p = 0.001 and 0.020, respectively) but the highest H/L ratio (0.83, p = 0.001). Corticosterone concentration was lower in control and H1 groups (5.49 and 6.41ng/mL, respectively, p = 0.024) than that in H2 group. Japanese quail exposed to heat stress revealed drop in production and immunological parameters, as well as a detrimental effects on welfare. Thus, practical approaches might be used to reduce the detrimental effects of greater THI level.

Effects of 25-hydroxycholecalciferol and soy isoflavones supplementation on bone mineralisation of quail

1. The effects of 25-hydroxycholecalciferol (25-OH-D3) and soy isoflavones supplementation on performance, carcase recovery, bone mineral density, and tibia ash, Ca, P, and serum vitamin D concentrations and alkaline phosphatase activity in the Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature were evaluated. 2. A total of 270 ten-d-old Japanese quail were randomly assigned to 9 treatment groups, 6 replicates of 5 birds each in a 2 × 3 × 3 factorial arrangement of treatments. Birds were kept in a temperature-controlled room at either 22°C (thermo-neutral) or 34°C (heat stress) for 8 h/d (09:00–17:00 h) and given a basal (control) diet or the basal diet supplemented with one of three levels of 25-OH-D3 (0, 250 and 500 IU/kg of diet) combined with one of three levels of soy isoflavones (0, 400 and 800 mg/kg of diet). 3. Birds kept at 34°C consumed less feed and gained less weight than control birds. An increase in body weight, feed intake (and improvement in feed efficiency and carcase recovery were found in soy isoflavones and 25-OH-D3-supplemented quail reared under heat stress conditions. Bone mineral density, tibia ash, Ca, and P were linearly improved by 25-OH-D3 and soy isoflavones supplementation in both thermoneutral and heat stress groups. Serum vitamin D levels and alkaline phosphatase activity were improved by 25-OH-D3 and soy isoflavones supplementation in both thermoneutral and heat stress groups in quail. 4. In conclusion, a combination of 25-OH-D3 and soy isoflavones supplementation to basal diet significantly improved bone mineralisation in quail.

Epigallocatechin-3-gallate supplementation can improve antioxidant status in stressed quail

1. Heat stress causes oxidative stress, which decreases plasma antioxidants in poultry. Epigallocatechin gallate (EGCG), the most abundant polyphenol in green tea, is a powerful antioxidant against lipid peroxidation. This experiment was conducted to evaluate the effects of dietary EGCG supplementation on performance, carcase characteristics, concentrations of malondialdehyde, lipid peroxidation indicator, vitamins C, E, A, cholesterol, triglyceride, and glucose in Japanese quail (Coturnix coturnix japonica) exposed to a high ambient temperature of 34°C. 2. One hundred and eighty Japanese quails (10 d old) were assigned at random to 6 treatment groups consisting of 10 replicates of three birds. Birds were kept in cages in a temperature-controlled room at either 22°C (thermo-neutral) or 34°C (heat stress) for 8 h/d. Birds were fed either a basal diet or the diet supplemented with 200 or 400 mg of EGCG/kg of diet. 3. EGCG supplementation linearly increased feed intake, live weight gain, feed efficiency, cold carcase weight and yield under heat stress conditions but did not show the same effect at thermoneutral conditions. Serum vitamin C, E, and A concentrations increased in birds reared at high temperature while non-significant changes occurred in thermo-neutral groups. Malondialdehyde concentrations in serum and liver decreased in all birds of both thermo-neutral and heat stressed groups as dietary EGCG supplementation increased. Heat stress-induced increase in serum cholesterol, triglycerides and glucose concentrations were linearly reversed by EGCG supplementation. 4. The results indicate that EGCG supplementation improved the live performance and antioxidant status of heat-stressed Japanese quail.

Effects of Chronic Heat Stress on Immune Responses of the Foot-and-Mouth Disease DNA Vaccination

The main purpose of this study was to assess the effects of chronic heat stress (CHS) on humoral and cellular responses of DNA vaccination. Mice with the CHS were exposed to a temperature set at 38 +/- 1 degrees C, 2h per day, for 35 days, and mice with thermoneutral (TN) temperature were maintained at 24 +/- 1 degrees C for the same period of time. Both groups of mice were immunized with a DNA vaccine-expressed viruscapsid protein 1 (VP1) of foot-and-mouth disease virus (FMDV), and we tested their antigen-specific humoral and cellular responses during the treatments. Compared with the TN group, titers of total Imunoglobulin G (IgG) and IgG1 and expression of interleukin 4 (IL-4) in CD4(+) cells of CHS group were not affected significantly. In contrast, the levels of IgG2a, T cell proliferations, and expression of interferon-gama (IFN-gamma) in both CD4(+) and CD8(+) cells were suppressed significantly, and cytotoxic T-lymphocyte (CTL) responses in vivo were also weakened by the CHS condition. These results indicate that the CHS treatment has negatively affected the immune responses of DNA vaccination and particularly impaired to the cell-mediated responses. It suggests that vaccination in animals is affected by the changes of ambient temperature.

Effects of Dietary Combination of Chromium and Biotin on Egg Production, Serum Metabolites, and Egg Yolk Mineral and Cholesterol Concentrations in Heat-Distressed Laying Quails

Chromium picolinate is used in the poultry diet because of its antistress effects in addition to the fact that the requirement for it is increased during stress. This study was conducted to determine if the negative effects of high ambient temperature (34 degrees C) on egg production, egg quality, antioxidant status, and cholesterol and mineral content of egg yolk could be alleviated by combination of chromium picolinate and biotin (0.6/2.0; Diachrome, as formulated by Nutrition 21 Inc.), in laying Japanese quails (Coturnix coturnix japanica). Quails (n= 240; 50 d old) were divided into 8 groups, 30 birds per group. The quails were fed either a basal diet or the basal diet supplemented with 2, 4, or 8 mg of Diachrome/kg diet. Birds were kept at 22 degrees C and 53% relative humidity (RH). At 14 wk of age, the thermoneutral (TN) group remained in the same temperature as at the beginning of experiment, whereas the heat stress (HS) group was kept in an environment-controlled room (34 degrees C and 41% RH) for 3 wk. Heat exposure decreased performance when the basal diet was fed (p = 0.001). Diachrome supplementation at 4 and 8 mg/kg diet, increased feed intake (p = 0.05), egg production (p = 0.05), feed efficiency (p = 0.01), egg weight (p = 0.05), and Haugh unit (p = 0.01) in quails reared under heat stress conditions. Heat exposure increased concentrations of serum malondialdehyde (MDA) (p = 0.001), glucose, and cholesterol (p = 0.01), which were elevated by supplemental Diachrome (p < or = 0.05). Egg yolk Cr, Zn, and Fe (p = 0.01) concentrations increased linearly, whereas MDA and cholesterol concentrations decreased (p = 0.05) as dietary Diachrome supplementation increased in HS groups. Similar effects of supplementation on serum levels of glucose and cholesterol (p = 0.05) and egg yolk concentrations of cholesterol (p = 0.05) and Cr (p = 0.01) were observed in TN groups. No significant differences in other values were observed in the TN groups. Results of the present study suggest that supplementation with Diachrome protects the quail by reducing the negative effects of heat stress.

Zinc Supplementation Alleviates Heat Stress in Laying Japanese Quail

The study was conducted to determine whether zinc supplementation could alleviate the detrimental effects of high ambient temperature (34 degrees C) on egg production, digestibility of nutrients and antioxidant status in laying Japanese quail. Quail (n = 180; 52 d old) were divided into six groups (n = 30/group) and were fed a basal diet or the basal diet supplemented with 30 or 60 mg of zinc (ZnSO(4). H(2)O)/kg diet. Birds were kept at 22 degrees C and 58% relative humidity (RH). At 13 wk of age, the thermoneutral (TN) groups remained at the same temperature, whereas the heat-stress (HS) groups were kept in an environmentally controlled room at 34 degrees C and 42% RH for 3 wk. Heat exposure decreased egg production in birds fed the basal diet (P = 0.001). Linear increases in feed intake (P = 0.01) and egg production (P = 0.004) and improved feed efficiency (P = 0.01) and egg quality variables (P <or= 0.05) occurred in zinc-supplemented groups reared under HS conditions. Heat exposure decreased digestibility of nutrients (P = 0.001), and these decreases were ameliorated by zinc supplementation (P <or= 0.05). Serum vitamin C (P = 0.05), vitamin E (P = 0.01) and zinc (P = 0.001) concentrations increased linearly, whereas malondialdehyde concentrations decreased (P = 0.002) as dietary zinc supplementation increased. No significant differences in any values were observed in the TN groups (P > 0.05). Results of the present study suggest that supplementation with 60 mg zinc/kg diet protects quail by reducing the negative effects of heat stress.