Pequi Oil (Caryocar brasiliense Camb.) Attenuates the Adverse Effects of Cyclical Heat Stress and Modulates the Oxidative Stress-Related Genes in Broiler Chickens.

Heat stress is a significant challenge in broiler chicken production, particularly in tropical and subtropical regions. This study evaluates the effectiveness of habituation in mitigating adverse effects of heat stress in broiler chickens during the hot-dry season. Sixty-day-old male broiler chicks (Arbor Acres) were randomly divided into control ( n = 30) and habituated groups ( n = 30). The habituated group was subjected to 4 days of habituation training from days 17 to 20. The two groups were subjected to tonic immobility (TI) test on day 21. Heterophil-to-lymphocyte (H:L) ratio, serum heat-shock protein 70 (Hsp70) expression, and erythrocyte osmotic fragility were assessed after the TI test. The results indicated that the thermal environment during the study period was characterised by high dry-bulb temperatures and high temperature-humidity index (THI), indicating significant thermal challenge on the broiler chickens. Habituated chickens showed significantly reduced TI durations compared to control. The H:L ratio and serum Hsp70 concentrations were markedly decreased (P < 0.05) in habituated chickens relative to controls. There was decreased (P < 0.05) erythrocyte membrane fragility in the habituated group, with reduced haemolysis compared to the control group. In conclusion, these findings show that the adverse effects of heat stress during the hot-dry season was mitigated in the habituated broiler chickens, as evidenced by reduced TI durations, a lower H:L ratio, decreased serum Hsp70 concentrations, and enhanced erythrocyte membrane stability. The study highlights the importance of habituation as a behavioural strategy in reducing sensitivity to heat stress in broiler chickens.

Alternative Measures of Physiological Stress in Nursery Pigs and Broiler Chickens

Background: Heat stress is one of the most important environmental stressors challenging poultry production worldwide. Understanding and controlling environmental stressors is crucial for successful poultry production. OBJECTIVES: The aim of the present study was to investigate the effects of melatonin supplementation and darkness regime on reducing the negative effects of heat stress in broiler chickens. METHODS: A total of 400 broiler chickens (Arian) were obtained and subjected to four different groups. The control chickens were grown in normal conditions without receiving any treatment. The positive control birds were grown similar to the control but exposed to an acute heat stress for 6 h/d from days 35 to 40. The dark group chickens were reared under a dark schedule and exposed to heat stress. The birds of the fourth group were reared similar to the positive control but received 40 ppm melatonin in the diet from days 30 to 40 of age. Dead birds were autopsied. The weekly growth performance of chickens was determined and blood samples were taken for hormonal analysis. RESULTS: The number of dead birds due to heat stress was significantly decreased in chickens subjected to the dark program and/or those which received melatonin in the diet compared with those of positive control chickens. Such differences were accompanied with the significantly lower levels of plasma T3, T3/T4 and corticosterone in these groups of chickens. Additionally, plasma thiobarbituric acid reacting substances level was significantly higher in positive control broilers compared to their counterparts. CONCLUSIONS: Our findings indicate a reduction of metabolic rate and heat production in dark regime and melatonin supplementation that can reduce the side effects of heat stress and, therefore, reduce the mortality rate.

High temperature is a known abiotic stressor in broiler chickens, causing oxidative damage and altering gene expression. The present study was conducted to study the role of in ovo feeding of taurine against heat-induced damage in the broiler chickens. It was hypothesized that pre-hatch supplementation with taurine induces epigenetic changes such as DNA methylation and demethylation, which could help develop resistance to heat stress (HS) at later stages of life. For this, at 17.5 days of incubation, 360 fertile eggs from 37-week-old Arbor Acre breeder hens were divided into four groups: injected with distilled water (0TAU) × 2, and others injected with taurine at 1 %, 3 %, or 5 % concentrations (1TAU, 3TAU, 5TAU). For the in ovo feeding, a 23-gauge needle was used to deposit 0.6mL of solution into the amniotic sac. During rearing days 29 to 34, broiler chickens were exposed to a cyclic heat stress (HS, 31 ± 1 °C, 8 hours) or kept at a thermoneutral temperature (TN) zone (21 ± 1 °C). Hence, the treatment groups were: (i) 0TAU-TN, (ii) 0TAU-HS, (iii) 1TAU-HS, (iv) 3TAU-HS, and (v) 5TAU-HS. While the organ indices, average daily feed intake (ADFI) and feed conversion ratio (FCR) did not differ significantly, in ovo taurine linearly increased average daily gain (ADG) during the heat stress (HS) period (p = 0.032). The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity% (DPPH-RSA%) in plasma showed a linear increase (p = 0.001) with taurine doses. Among the studied plasma metabolites, only alanine transaminase (ALT) was significantly affected, being lower in 1TAU-HS and 3TAU-HS compared to 5TAU-HS (p = 0.022). Individual gene expressions showed no significant variation across treatments. However, a planned contrast revealed upregulation of DNA methylation genes in the 5TAU-HS group compared to the 0TAU-TN group (p = 0.030). Strong positive correlations were observed among DNA methylation, demethylation, and NADPH oxidase (NOX) -related genes, suggesting coordinated regulation. Negative correlations between MDA and antioxidant enzymes indicated oxidative stress-related damage under HS. Hence, taurine linearly improved ADG under HS. While it did not significantly influence individual gene expression, 5TAU upregulated the overall DNA-methylation-related genes, suggesting a possible long-term adaptive response under HS.

BackgroundHeat stress is a significant problem in the poultry industry, causing a severe economic loss due to its detrimental effects on chickens’ health and performance. Dried plum (DP) is a good source of minerals, vitamins, antioxidants, and phenolic compounds. Studies have suggested that DP has several health benefits, such as maintaining the body’s redox system, immune status, and calcium hemostasis. Based on the health benefits of DP, we hypothesized that the dietary supplementation of DP would alleviate the detrimental effects of heat stress on broiler chickens.ResultsTo test the hypothesis, day-old broiler chicks (n = 72) were randomly allocated to three treatment groups (n = 24/group): no heat stress (NHS), heat stress (HS), and heat stress with dried plum (HS + DP), and reared under standard conditions. The inclusion of 2.5% DP in the feed of the HS + DP group was made during the treatment period, while birds in other groups were provided with a standard finisher diet. After 21 days, birds in the HS and HS + DP groups were exposed to cyclic heat stress conditions (33 °C for 8 h during daytime) for 3 weeks, while those in the NHS group were reared under normal conditions (22–24 °C). Weekly body weight and feed intake were recorded to calculate the average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR). Heat stress significantly decreased the final body weight, ADG, ADFI, and increased FCR compared to the NHS group, whereas dietary supplementation of DP significantly improved these growth performance parameters compared to the HS group. Furthermore, supplementation of DP significantly increased the expression of heat shock protein-related genes (HSF1, HSF3, HSP70, and HSP90), antioxidant-related genes (SOD1, SOD2, GPX1, GPX3, PRDX1, and TXN), tight junction-related genes (CLDN1, and OCLN), and immune-related genes (IL4, MUC2) in the ileum as compared to the HS group. The microbiota analysis showed significant enrichment of Bacillales, Christensenellaceae, Bacillaceae, Peptostreptococcaceae, and Anaerotruncus in heat-stressed birds supplemented with DP as compared to the HS group. Further, DP supplementation also significantly increased the concentration of acetate, propionate, and total VFA in the cecal digesta of the HS + DP group as compared to the HS group.ConclusionThese findings suggest that DP supplementation effectively improved the growth performances and gut health parameters in the heat-stressed birds. Thus, dried plum can be a potential feed supplement to mitigate heat stress in broiler chickens.

Curcumin attenuates heat-stress-induced oxidant damage by simultaneous activation of GSH-related antioxidant enzymes and Nrf2-mediated phase II detoxifying enzyme systems in broiler chickens

<p class="awabstrak2"><span lang="EN-US">Heat stress is an important issue in broiler chicken farms in tropical countries, such as Indonesia. Heat stress is very detrimental to broiler chickens because reducing production performance, health, and causing mortality. In the condition of heat stress, broilers synthesize Heat Shock Protein (HSP) quickly as the body's response to heat stress. HSP 70 is the most studied HSP group related to heat stress. The objective of this study was to review the nutritional approach that has been done to mitigate heat stress in broiler chickens with the HSP70 gene expression as its indicator. Based on some studies, nutritional approaches that can be taken are through the management of feed availability, supplementation of vitamin C, vitamin E, plant bioactives, amino acids (taurine and glutamine), probiotics, prebiotics, synbiotics, manan oligo saccharide (MOS) and minerals (selenium, zinc, manganese, chromium). By these approaches, HSP70 gene expression decreased indicating that the heat stress level of broiler chicken also reduced. It can be concluded that the nutritional approach can be used as a method for heat stress mitigation in broilers with the HSP70 gene expression indicator. </span></p>

BackgroundHigh environmental temperatures induce heat stress in broiler chickens, affecting their health and production performance. Several dietary, managerial, and genetics strategies have been tested with some success in mitigating heat stress (HS) in broilers. Developing novel HS mitigation strategies for sustaining broiler production is critically needed. This study investigated the effects of pre-hatch thermal manipulation (TM) and post-hatch baicalein supplementation on growth performance and health parameters in heat-stressed broilers.ResultsSix hundred fertile Cobb 500 eggs were incubated for 21 d. After candling on embryonic day (ED) 10, 238 eggs were thermally manipulated at 38.5 °C with 55% relative humidity (RH) from ED 12 to 18, then transferred to the hatcher (ED 19 to 21, standard temperature) and 236 eggs were incubated at a controlled temperature (37.5 °C) till hatch. After hatch, 180-day-old chicks from both groups were raised in 36 pens (n = 10 birds/pen, 6 replicates per treatment). The treatments were: 1) Control, 2) TM, 3) control heat stress (CHS), 4) thermal manipulation heat stress (TMHS), 5) control heat stress supplement (CHSS), and 6) thermal manipulation heat stress supplement (TMHSS). All birds were raised under the standard environment for 21 d, followed by chronic heat stress from d 22 to 35 (32–33 °C for 8 h) in the CHS, TMHS, CHSS, and TMHSS groups. A thermoneutral (22–24 °C) environment was maintained in the Control and TM groups. RH was constant (50% ± 5%) throughout the trial. All the data were analyzed using one-way ANOVA in R and GraphPad software at P < 0.05 and are presented as mean ± SEM. Heat stress significantly decreased (P < 0.05) the final body weight and ADG in CHS and TMHS groups compared to the other groups. Embryonic TM significantly increased (P < 0.05) the expression of heat shock protein-related genes (HSP70, HSP90, and HSPH1) and antioxidant-related genes (GPX1 and TXN). TMHS birds showed a significant increment (P < 0.05) in total cecal volatile fatty acid (VFA) concentration compared to the CHS birds. The cecal microbial analysis showed significant enrichment (P < 0.05) in alpha and beta diversity and Coprococcus in the TMHSS group.ConclusionsPre-hatch TM and post-hatch baicalein supplementation in heat-stressed birds mitigate the detrimental effects of heat stress on chickens' growth performance, upregulate favorable gene expression, increase VFA production, and promote gut health by increasing beneficial microbial communities.

Effects of yeast fermentate supplementation on cecal microbiome, plasma biochemistry and ileal histomorphology in stressed broiler chickens

This study was conducted to explore the effect of the zinc oxide nanoparticles (ZnONPs) supplement on the regulatory appetite and heat stress (HS) genes in broiler chickens raised under high or normal ambient temperatures. In this study, 240 one-day-old male broiler chicks (Cobb 500) were randomly assigned to 48 battery cages. From day 1, these 48 cages were randomly subjected to four different treatment strategies: Control (wherein, their basal diet included 60 mg/kg of ZnO), ZNONPs 40 (wherein basal diet included 40 mg/kg of ZnONPs), ZnONPs 60 (basal diet included 60 mg/kg of ZnONPs), and ZnONPs 100 (basal diet included 100 mg/kg of ZnONPs). Thereafter, from day 22 to 42, the chickens from each dietary treatment group were subjected to different temperature stresses either normal (23 ± 1 °C constant) or HS (34 ± 1 °C for 6 h/d), which divided them into eight different treatment groups. Our findings revealed that dietary ZnONPs altered the gene expression of cholecystokinin (ileum), heat stress proteins (HSP) 70 (jejunum and ileum), and HSP 90 (duodenum, jejunum, and ileum). The gene expression of ghrelin was affected by the interaction between the ZnONPs concentration and temperature in the duodenum and stomach. More studies are required to elucidate its complex physiological and biochemical functions of the regulation of gene expression within the intestine in heat-stressed broiler chickens.

To assess effects of environmental heat stress (HS) on the local and systemic inflammatory responses to lipopolysaccharide (LPS), broilers were reared under thermoneutral (TN) or cyclic HS conditions. Thermoneutral temperatures followed commercial production settings, with HS broilers exposed to 35 °C for 14 h/day from 4 days onward. At 37 days, HS- and TN-broilers were assigned to either LPS (100 μg/mL) or endotoxin-free phosphate-buffered saline (PBS; vehicle) treatments, eight each to HS- and TN-LPS, four each to HS- and TN-PBS. Treatments were administered by intradermal injection of growing feather (GF) pulps; 10 μL/GF; 12 GF/broiler. Blood and GF were collected before and at 6 and 24 h post-injection to assess leukocyte population changes in GF-pulps and blood, reactive oxygen species (ROS) generation and cytokine expression in GF-pulps, and plasma concentrations of alpha-1 acid glycoprotein (AGP-1). HS-LPS broilers had lower (p ≤ 0.05) infiltration of heterophils and macrophages, ROS generation, and inflammatory cytokine expression in GF-pulps, and lacked the increases in heterophil, monocyte, and plasma AGP-1 concentrations observed in TN-LPS broilers. HS-broilers had similar or greater drops in blood lymphocytes 6 h post-LPS or -PBS injection, respectively, and lower baseline levels (p ≤ 0.05) of circulating T- and B-lymphocytes than TN-broilers. Results indicated that cyclic HS reduced the local and systemic acute inflammatory responses to LPS in broilers, likely impairing their innate defense against microbial infection.

Little attention has been paid to the biological role of arginine and its dietary supplementation in broilers under heat stress (HS) conditions. Therefore, the main aim of this study was to assess the response of broilers to arginine supplementation and cyclic HS, with a focus on liver, pectoral muscle, and blood metabolic profiles and the cecal microbiota. Day-old male Ross 308 broilers (n = 240) were placed in 2 rooms with 12 pens each for a 44-day trial. Pens were assigned to one of two groups (6 pens/group/room): the control group (CON) was given a basal diet in mash form and the treated group (ARG) was fed CON diet supplemented with crystalline L-arginine. The total arginine:lysine ratio of CON diet ranged between 1.02 and 1.07, while that of ARG diet was 1.20. One room was constantly kept at thermoneutral (TN) conditions, while the birds in the other room were kept at TN conditions until D34 and subjected to cyclic HS from D35 onwards (∼34°C; 9:00 A.M.-6:00 P.M.). Blood, liver, Pectoralis major muscle, and cecal content were taken from 2 birds per pen (12 birds/group/room) for metabolomics and microbiota analysis. Growth performance data were also collected on a pen basis. Arginine supplementation failed to reduce the adverse effects of HS on growth performance. Supplemented birds showed increased levels of arginine and creatine in plasma, liver, and P. major and methionine in liver, and reduced levels of glutamine in plasma, liver, and P. major. HS altered bioenergetic processes (increased levels of AMP and reduced levels of fumarate, succinate, and UDP), protein metabolism (increased protein breakdown to supply the liver with amino acids for energy production), and promoted the accumulation of antioxidant and protective molecules (histidine-containing dipeptides, beta-alanine, and choline), especially in P. major. Arginine supplementation may have partially counterbalanced the effects of HS on energy homeostasis by increasing creatine levels and attenuating the increase in AMP levels, particularly in P. major. It also significantly reduced cecal observed diversity, while HS increased alpha diversity indices and affected beta diversity. Results of taxonomic analysis at the phylum and family level are also provided.

Heat stress is one of the major environmental factors affecting the productivity and survival of broiler chickens in the North east region of Nigeria. Tamarindus indica (T. indica) fruit pulp is an alternative cheaper plant product with the potential to mitigate heat stress in broiler chickens. An experiment was conducted for 21 days to evaluate the effects of T.indica fruit pulp solution on the productive performance and carcass characteristics of broiler chickens during heat period (March to April, 2024) in Mubi area of Adamawa State, Nigeria. The experiment consist of five treatments, the first treatment has zero supplementation anti-stress T1 (0 g/L), second treatment has commercial anti-stress T2 (CAS) in water, while treatments three, four and five (T3, T4 and T5) contain clean dried T. indica fruit pulp soaked in water for 24 hours at room temperature at concentrations of 10, 20 and 30 g/L, respectively and thereafter sieved to obtained the T. indica fruit pulp solution that was supplied to the chickens. A total of 150 four weeks old broiler chickens were randomly allotted to the treatments in a Completely Randomized Design replicated three times with 10 broiler chickens each. The result of productive performance revealed significant variation (P&lt;0.05) except for the total and daily feed intake. The highest weight gain and the best feed conversion ratio were recorded in T5 (2250 g) and (2.05) while the worst feed conversion ratio was observed in T1 (3.15). The carcass characteristics were not significantly (P&lt;0.05) affected by the treatments except for the wings which indicated higher values in T3 (7.05%), T4 (7.22%) and T5 (7.17%). However, the dressing percentage of the broiler chickens ranged from 76.6 to 78.20%. It was concluded from this study that T. indica fruit pulp can be supplemented in drinking water of broiler chickens up to 30 g/L without compromising the productive performance and carcass characteristics of broiler chickens and is therefore the recommended level for combating heat stress in broiler chickens.

Global warming has become intensified and widespread, threatening the world with causing acute heatwaves that adversely affect poultry production and producers' profitability. Spirulina platensis is a precious and promising mitigating strategy to combat the detrimental impacts of heat stress due to its high contents of nutrients and bioactive components. The current study was designed to compare the incorporation impact of S. platensis powder or aqueous extract on the growth and physiological responses of heat-stressed broiler chicks. Six hundred 1-day-old Ross 308 male broiler chicks were allocated into five experimental groups with six replicates of 20 chicks each. The control group fed the basal diet without additives, SPP1 and SPP2 groups fed the basal diet with 1 g/kg and 2 g/kg S. platensis powder, respectively, while SPE1 and SPE2 groups received 1 ml/L and 2 ml/L S. platensis aqueous extract in the drinking water, respectively. All birds were exposed to cyclic heat stress (34 ± 2 °C for 12 h) for three successive days a week from day 10 to day 35. In vitro analysis showed that total phenols, flavonoids, and antioxidant activity of S. platensis were remarkably decreased (P < 0.001) in the aqueous extract compared to the powder form. Body weight, weight gain, and feed conversion ratio were improved (P < 0.001) in all treated groups, while carcass yield and dressing percentage were increased only in SPP1 and SPP2. Feed and water intake and blood biochemical parameters were not affected. Both forms of S. platensis enhanced the lipid profile, redox status, and humoral immune response of heat-stressed chicks superior to the powder form. Conclusively, the powder form of S. platensis was more effective in enhancing the productivity of broilers and alleviating the negative impacts of heat stress than the aqueous extract form.

Heat stress remains a major challenge for the poultry industry, particularly in tropical regions and warm seasons, where it negatively impacts poultry welfare and performance, leading to economic losses. Although heat stress has been a long-term concern for the poultry industry, existing solutions only partially alleviate the negative impacts on overall productivity. Enhancing our understanding of this challenge and available solutions can aid in shaping future initiatives to develop more robust solutions for managing heat stress. This review explores recent strategies developed to mitigate heat stress in broiler chickens, including genetic selection, nutritional approaches such as vitamins (C, E, A, and B groups), amino acids, electrolytes, environmental modifications, and improving behavioral monitoring systems. Furthermore, we discussed the challenges in reducing the impacts of heat stress. Integrating these diverse strategies can improve poultry resilience, ensuring better welfare and sustainable production systems. Therefore, this review contributes to advancing adaptive strategies to safeguard poultry in a warming world.