Stress In Broiler Chickens Research Articles

Effects of Rhamnolipids on Growth Performance, Immune Function, and Cecal Microflora in Linnan Yellow Broilers Challenged with Lipopolysaccharides.

This present study aimed to investigate the effects of rhamnolipids (RLS) on the growth performance, intestinal morphology, immune function, short-chain fatty acid content, and microflora community in broiler chickens challenged with lipopolysaccharides (LPS). A total of 450 broiler chickens were randomly allocated into three groups: basal diet with no supplement (NCO), basal diet with bacitracin (ANT), and basal diet with rhamnolipids (RLS). After 56 d of feeding, 20 healthy broilers were selected from each group, with half being intraperitoneally injected with lipopolysaccharides (LPS) and the other half with normal saline. Treatments with LPS were labelled LPS-NCO, LPS-ANT, and LPS-RLS, whereas treatments with normal saline were labelled NS-NCO, NS-ANT, and NS-RLS. LPS-challenged birds had lower jejunal villus height and higher crypt depth than unchallenged birds. LPS-RLS broilers had increased jejunal villus height and villus height/crypt depth ratio (V/C) but lower crypt depth than LPS-NCO. Dietary supplementation with RLS reduced the LPS-induced immunological stress. Compared with LPS-NCO, birds in LPS-RLS had lower concentrations of IL-1β, IL-6, and TNF-α. In LPS-challenged broilers, RLS and ANT increased the concentrations of IgA, IgM, and IgY compared with LPS-NCO. In LPS treatments, RLS enhanced the contents of acetic acid, butyrate, isobutyric acid, isovalerate, and valerate more than LPS-NCO birds. High-throughput sequencing indicated that RLS supplementation led to changes in the cecal microbial community of broilers. At the species level, Clostridium-sp-Marseille-p3244 was more abundant in NS-RLS than in NS-NCO broilers. In summary, RLS improved the growth performance and relative abundance of cecal microbiota and reduced the LPS-induced immunological stress in broiler chickens.

The effects of the mixture of betaine, vitamin C, St John's wort (Hypericum perforatum L.), lavender, and Melissa officinalis on performance and some physiological parameters in broiler chickens exposed to heat stress

The unprecedented rate of global warming requires more immaculate strategies to fight the heat stress and its detrimental effects on poultry sector. Nutritional strategies, particularly herbal extracts, play a crucial importance in this scenario. Therefore, this study was conducted to evaluate the effects of a novel selected mixture (hereafter refers to as Stress-Bio-Max, SBM) comprising St John's wort, lavender, Melissa officinalis extracts, betaine, and Vit C on heat-stressed broilers. A total of 300 male broiler chicks were allocated to 4 treatments: T1, Control (no SBM in drinking water); T2, 0.25 mL/L of SBM in drinking water; T3, 0.5 and T4, 1 mL/L of SBM, which applied since d 32. The birds underwent heat stress (40 ± 1) daily from d 35 to 42 of the experiment (2 pm–8 pm). The results show the superior weight gain of T2 and T3 from d 7 to 42 compared to other groups, 72.5 and 72.7 g/d, respectively (P < 0.05). Corticosterone level was higher on d 35 in T1 (4.674 ng/mL, P < 0.05) and lower in T2 and T3 (2.64 and 2.952 ng/mL, respectively, P < 0.05); T2 and T3 also caused the lowest concentrations of corticosterone on d 40 (5.198 and 6.458 ng/mL, respectively, P < 0.05). The superior triiodothyronine levels belonged to T2 (0.935 ng/mL, P < 0.05) on d 35 and T2 and T3 on d 40 (0.699 and 0.582 ng/mL, respectively, P < 0.05). T2, T3, and T4 caused a rise in glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities (P < 0.05). A significant higher amount of total antioxidant capacity (TAC) belonged to the groups treating with SBM (P < 0.05). The SBM in T2 and T3 resulted in the lowest levels of malondialdehyde (MDA), aspartate transaminase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). Results from this study indicate that SBM may alleviate the negative impacts associated with heat stress in broiler chickens.

Heat Stress in Broiler Chickens and the Effect of Dietary Polyphenols, with Special Reference to Willow (Salix spp.) Bark Supplements-A Review.

Over the last decade, there has been a growing interest in the use of a wide range of phytoadditives to counteract the harmful effects of heat stress in poultry. Willow (Salix spp.) is a tree with a long history. Among various forms, willow bark is an important natural source of salicin, β-O-glucoside of saligenin, but also of polyphenols (flavonoids and condensed tannins) with antioxidant, antimicrobial, and anti-inflammatory activity. In light of this, the current review presents some literature data aiming to: (1) describe the relationship between heat stress and oxidative stress in broilers, (2) present or summarize literature data on the chemical composition of Salix species, (3) summarize the mechanisms of action of willow bark in heat-stressed broilers, and (4) present different biological effects of the extract of Salix species in different experimental models.

Dietary supplementation of dried plum: a novel strategy to mitigate heat stress in broiler chickens

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.

Effects of Bile Acids on Growth Performance and Lipid Metabolism during Chronic Heat Stress in Broiler Chickens.

Simple SummaryThe negative impacts of heat stress (HS) on growth performance and lipid metabolism have been reported, but there are still no effective nutritional strategies to alleviate heat stress. Bile acids are new for their antioxidative properties and regulatory effect on lipid metabolism. This study was carried out to evaluate the growth performance and lipid metabolism in chickens under heat stress when fed with bile acid supplements in their diet. The results showed that mild heat stress (32 °C) induced hepatic lipogenic gene (hepatic SREBP-1c) expressions and lipid deposition, without obvious tissue damage in broilers. Dietary supplementation of bile acid could decrease hepatic lipid deposition without affecting endogenous bile acid biosynthesis. Therefore, bile acid supplements can benefit broiler chickens during high ambient temperatures, serving as a new nutritional strategy against heat stress.This study aimed to investigate whether dietary bile acid (BA) supplements can improve growth performance and lipid metabolism in heat-stressed broiler chickens. A total of 288 Arbor Acres broilers were blocked by BW and then randomly allocated into 4 treatments at 21 days of age. Birds reared under 32 °C had a higher cloacal temperature (p = 0.01), faster respiratory rate (p < 0.001), and a greatly reduced average daily feed intake (ADFI, p = 0.016), average daily gain (ADG, p = 0.006), final body weight (FBW, p = 0.008), and feed conversion rate (FCR, p = 0.004). In heat stress (HS) birds, the breast muscle rate (p = 0.006) and pH 24 h postmortem (p = 0.065) were lower, and the shear force was higher (p = 0.027). Dietary BA supplements tended to increase the breast muscle rate (p = 0.075) without affecting the growth performance and serum lipids (p > 0.05). Serum total bile acid (TBA) was roughly duplicated after BA supplements (p = 0.001). In the liver, total cholesterol was lower (p = 0.046), and triglycerides were higher (p = 0.04) in the HS birds, whereas the expression of SREBP-1c showed an increasing trend (p = 0.06). In contrast, dietary BA decreased triglycerides and the expressions of hepatic SREBP-1c and FAS in the liver (p < 0.05). In summary, mild HS causes hepatic lipid accumulation without obvious tissue damages, whereas BA has positive effects on relieving abnormal lipid metabolism, indicating that BA as a nutritional strategy has a certain potential in alleviating HS.

The Effects of Conjugated Linoleic Acid and Berberine Supplementation on Markers of Allopurinol Activated Oxidative Stress in Broiler Chickens

Selection for rapid growth in poultry can be linked to an exaggerated state of oxidative stress (reactive oxidative species). Reactive oxidative species are kept in balance by endogenous and exogenous antioxidants. Two compounds, conjugated linoleic acid (CLA) and berberine a purified compound from plant root extract have been suggested to ameliorate oxidative stress. A six-week study examined the effect of CLA and berberine supplementation on markers of oxidative-stress in poultry. Day old broiler chickens (n=60) were equally divided into six groups; a control, a CLA group where half of the regular oil used in a standard was substituted for a CLA oil mixture, a berberine group consisting of berberine supplementation, an allopurinol group, a CLA and allopurinol with the same dose as the CLA and allopurinol groups and a berberine and allopurinol group. The allopurinol was added to induce an oxidative stress state. Body weight, plasma uric acid, plasma glucose, and relative gene expression of six endogenous liver antioxidants were measured during the course of the study. The addition of allopurinol to the diet induced an oxidative stress state as measured by a significant reduction in plasma uric acid. There were no significant changes in BW and blood glucose concentrations. There was a 10-fold increase in the relative mRNA expression of superoxide dismutase 2 and 3 as well as glutathione peroxidase 1 and 3 in CLA+ALLO and BRB+ALLO treatment groups. Notably, CLA increased the expression of uncoupling protein 19-fold compared to control, while the addition of allopurinol blocked these changes. In contrast, there was a slight increase in the uncoupling protein in the BRB+ALLO treatment. Despite the increase in mRNA expression of the antioxidants genes, these results suggest that at the dosages administered, CLA and berberine were not effective in reversing the oxidative stress induced by allopurinol.

Cloacal temperature responses of broiler chickens administered with fisetin and probiotic (Saccharomyces cerevisiae) and exposed to heat stress

Abstract There is dearth information on the role of fisetin as an antistress agent in ameliorating heat stress in broiler chickens. Here, we experimentally compared probiotic, an antioxidant and antistress agent, with fisetin, an antioxidant agent with little or no report on its antistress effect. Sixty-day-old broiler chickens (Arbo Acre breed) were allotted into 4 groups of 15 birds each as follows; control, fisetin, probiotic, and fisetin + probiotic groups, respectively. All administrations were performed orally through gavage for the treatment groups. The environmental and cloacal temperature (CT) parameters were measured bi-hourly at Days 21, 28, and 35 from 7:00 to 7:00 hr, during the period of study. The environmental parameters exceeded the thermoneutral zone for broiler chickens. The probiotic-supplemented group had the least overall mean CT values all through the experimental period. Based on our findings, fisetin was not a potent antistress agent in mitigating heat stress in birds.

Mitigation of Heat Stress in Broiler Chickens with Heat Shock Protein 70 Gene Expression as its Indicator

&lt;p class="awabstrak2"&gt;&lt;span lang="EN-US"&gt;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. &lt;/span&gt;&lt;/p&gt;

Impact of Heat Stress on Poultry Health and Performances, and Potential Mitigation Strategies.

Simple SummaryHigh environmental temperature alters the poultry health and performances by causing heat stress. Heat stress elicits physiological, behavioral, and production changes in poultry. This review article summarizes these changes along with the strategies that have been used in the poultry industry to ameliorate the adverse effects of heat stress in poultry.Heat stress is one of the major environmental stressors in the poultry industry resulting in substantial economic loss. Heat stress causes several physiological changes, such as oxidative stress, acid-base imbalance, and suppressed immunocompetence, which leads to increased mortality and reduced feed efficiency, body weight, feed intake, and egg production, and also affects meat and egg quality. Several strategies, with a variable degree of effectiveness, have been implemented to attenuate heat stress in poultry. Nutritional strategies, such as restricting the feed, wet or dual feeding, adding fat in diets, supplementing vitamins, minerals, osmolytes, and phytochemicals, have been widely studied and found to reduce the deleterious effects of heat stress. Furthermore, the use of naked neck (Na) and frizzle (F) genes in certain breed lines have also gained massive attention in recent times. However, only a few of these strategies have been widely used in the poultry industry. Therefore, developing heat-tolerant breed lines along with proper management and nutritional approach needs to be considered for solving this problem. Thus, this review highlights the scientific evidence regarding the effects of heat stress on poultry health and performances, and potential mitigation strategies against heat stress in broiler chickens and laying hens.

Probiotic bacteria maintain normal growth mechanisms of heat stressed broiler chickens.

Probiotics have growth promoting effects even under periods of heat stress challenge. More information is needed to understand the mechanisms by which probiotics maintain the growth performance. The aim of this study was to evaluate the effect of a probiotic based on Bacillus subtilis bacteria on growth related mechanisms of broilers under heat stress conditions. Specifically, growth performance, skeletal bone characteristics, skeletal muscles size, intestinal villus-crypt structure, intestinal bacteria, growth hormone (GH), insulin-like growth factor-1 (IGF-1), cholesterol, and glucose. A total of 1200 one day old Ross 308 male broilers were randomly distributed into 4 treatments, with 12 replicates per treatment and 25 birds per replicate. A 2×2 factorial arrangement was used; the main factors were environmental temperature (thermoneutral or heat stress) and diet (control or control+B. subtilis; 3×107cfu/kg of feed). From d 22 to 35 of age, birds were either exposed to thermoneutral conditions (21°C) or chronic heat stress (30°C). During the same period, each group was divided into 2 subgroups and fed either the control diet or the B. subtilis supplemented diet. The results demonstrated that B. subtilis had positive effects (P<0.05) on the body weight gain, feed conversion ratio, villus height, crypt depth, villus surface area, absorptive epithelial cell area and viable counts of intestinal beneficial bacteria. B. subtilis increased (P<0.05) serum GH, IGF-1 and maintain normal levels of cholesterol and glucose under heat stress conditions. In addition, broilers fed B. subtilis under heat stress conditions exhibited higher (P<0.05) skeletal muscles size and improved (P<0.05) tibia traits and lower (P<0.05) abdominal fat pads deposition compared with the controls. B. subtilis had no effect on rectal temperature under thermoneutral or heat stress conditions. It is concluded that B. subtilis can be used as growth promoters in broilers, particularly during the periods of heat stress conditions.

The influence of diets with dry corn barda and intermittent feeding mode on the productive and biological traits of broiler chickens

The inclusion of dry corn barda in diets helps to solve the problem of obtaining inexpensive feed protein for broilers, but the effectiveness of its use in different doses has not been studied good enough. The use of different intermittent feeding programs, as of a intermittent feeding mode can reduce the severity of heat stress in broiler chickens. However, the optimal duration of the break in feeding broiler chickens in the hottest daytime hours is not established in detail. The purpose of the researches was to determine the effect of diets with dry corn barda and intermittent feeding mode with the addition of the complex of trace elements (chromium, zinc) and vitamins (ascorbic acid, antisterility vitamin) on the productive and biological characteristics of broiler chickens at high air temperature in the hot arid climate. The productive and biological trats of broiler chickens have been determined when using 5, 10, 15 % dry corn barda in diets. Data on the productive and biological parameters of broiler chickens of the cross Ross-308 have been obtained when using intermittent feeding mode of different duration (2, 3, 4 hours). New data have been obtained on the productive and biological parameters of broiler chickens cross Ross-308 when using additives in feed of different doses of trace elements (Cr, Zn) and vitamins (C, E). The optimal parameters of the duration of intermittent feeding mode and the dose of trace elements (Cr, Zn) and vitamins (C, E) added to the feed have been revealed. It has been found that the inclusion of dry corn barda in the diet of broiler chickens and the influence of intermittent feeding mode with the addition of the complex of trace elements (Cr, Zn) and vitamins (C, E) in the feed improves the functional state of the body and increases the productivity of broiler chickens at elevated air temperature in the hot arid climate.

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

Heat stress, a common stressor in commercial poultry production, negatively affects growth and intestinal function of broiler chickens. Two experiments were conducted to evaluate the effects of a Saccharomyces cerevisiae-derived yeast fermentation product on cecal microbiome and indicators of intestinal barrier function in stressed broiler chickens. Yeast fermentate (YF) was added to the feed (1.25 kg/t) or drinking water (1.60 mL/L) for the duration of each experiment. In Exp. 1, 1-D-old male broiler chickens (N = 300 birds/treatment) were assigned to 1 of 3 treatments: stressed control (CS), stressed + YF in the feed (XS), and stressed + YF in the drinking water (AS). All birds were reared on re-used litter (d 0 to 42) and spray-vaccinated for coccidiosis (d 0). On d 18, all birds were spray-vaccinated for Newcastle/Bronchitis, then exposed to a 12 h concurrent heat stress and feed and water withdrawal. Cecal microbiome did not differ in composition or diversity between or within treatments on d 42. In Exp. 2, 1-D-old male broiler chickens (N = 40 birds/treatment) were reared to 43 d of age. Treatments included CS, XS, AS, non-stressed control (CN), non-stressed + YF in the feed (XN), and non-stressed + YF in the drinking water (AN). Stressed treatments were exposed to cyclic heat stress d 28 to 43 for 12 h/d. Blood samples collected on d 42 were used to analyze plasma chemistry, interleukin(IL)-1α, IL-8, and alpha-1-acid glycoprotein (α1-AGP); ileum samples collected on d 43 were used to assess histomorphology. Heat stress increased plasma creatine kinase (P < 0.001), uric acid (p < 0.001), sodium/potassium ratio (P < 0.001), and IL-1α (P < 0.001), but decreased alkaline phosphatase (P = 0.04), potassium (P < 0.001), IL-8 (P < 0.001), and α1-AGP (P = 0.048). Plasma glutamate dehydrogenase was higher in birds fed the control diet or YF in the feed (P < 0.001) compared to birds supplemented with YF in the drinking water. Heat stress decreased villus height (P < 0.001) and crypt depth (P < 0.001), and increased villus/crypt ratio (P < 0.001) and goblet cell density (P < 0.001). Supplementing YF in the drinking water increased villus height (P < 0.001) and crypt depth (P = 0.036) compared to supplementing YF in the feed. Adding YF to the drinking water may be an effective method to mitigate heat-stress induced changes in villus height and crypt depth during cyclic heat stress.

Strategies to Combat Heat Stress in Broiler Chickens: Unveiling the Roles of Selenium, Vitamin E and Vitamin C

Heat stress compromises efficient poultry production by impairing growth performance and increasing mortality. Mechanisms to dissipate excess heat divert energy from efficient production. This includes increased energy expenditure for respiration, oxidative stress and micronutrient absorption. The fortification of diets with particular feed additives has been known as one of the most important approaches to minimize the negative impacts of heat stress on broiler production. In this context, the promising functional feed additives appeared to be selenium and vitamins E and C. The fortification of broiler diets with these feed additives has been proven to enhance the function of vital organs, immune system response and growth performance of broilers under heat stress. The current review highlights recent successful experiences in the alleviation of heat stress symptoms in broilers using the above-mentioned additives. Selenium and vitamins E and C enhanced production performance in broiler chickens challenged with acute heat stress. The combination of these additives, by employing multiple mechanisms and through synergistic effects, improves heat stress symptoms more efficiently than their individual forms. Emerging literature reveals that selenium and vitamins E and C are involved in close interactions to protect proteins and lipids from oxidative damage and boost immune system function.

HSF3 and Hsp70 Expression during Post-Hatch Cold Stress in Broiler Chickens Subjected to Embryonic Thermal Manipulation.

Decades of selective breeding for commercial purposes have rendered the broiler chicken (Gallus gallus domesticus) highly susceptible to heat and cold stress. A multitude of studies have documented the effects of thermal manipulation (TM) on broiler thermotolerance during periods of post-hatch heat stress, but very few have focused on the effect of TM on a broiler’s ability to withstand cold stress. Therefore, the primary objective of the current study is to determine the effects of TM on the acquisition of thermotolerance in broilers via their expression of the stress-associated 70 kilodalton heat shock protein (Hsp70) gene and heat shock factor 3 (HSF3) gene. Briefly, Hubbard broiler embryos were subject to TM by increasing the incubation temperature to 39 °C and 65% relative humidity (RH) for 18 h daily, from embryonic days (ED) 10 to 18. Broilers were then exposed to cold stress by decreasing the room temperature to 16 °C during post-hatch days 32 to 37. After thermal challenge, broilers were euthanized and hepatic and splenic tissues were collected. Our results showed that TM decreased the hatchability rate and body temperature but improved the body weight gain. TM generally decreased the hepatic expression but did not change the splenic expression of HSF3 during cold stress. In contrast, both hepatic and splenic Hsp70 expression decreased during cold stress. The results of the present study may suggest that TM significantly affects a broiler’s genetic response to cold stress.

Splenic Gene Expression Signatures in Slow-Growing Chickens Stimulated in Ovo with Galactooligosaccharides and Challenged with Heat.

Simple SummaryThe exposure of animals to excessive heat leads to heat stress, heat stroke, or even death. The first negative effects of heat exposure occur in the gut. The elevated temperature leads to damage in intestinal walls and shifts in the composition of intestinal microbiota. In effect, the gut content (mainly intestinal microbiota and their metabolites) leaks through compromised intestinal walls into milieu of the body. Prebiotics (e.g., GOS—galactooligosaccharides) can be used to mitigate the negative effects of the heat stress in poultry. GOS that are delivered in ovo on day 12 of egg incubation stimulates the development of healthy intestinal microbiota in a chicken embryo. Healthy intestinal microbiota enhances the barrier function of the gut and the immune system. Chickens were originally domesticated in southeast Asia and are therefore genetically adapted to handle high temperatures. However, genetic selection towards performance leads to sensitization to high ambient temperature. In this paper, we studied slow-growing chickens with a reputation for heat resistance. We used in ovo stimulation with the GOS prebiotic that was delivered in ovo to promote healthy gut microbiota. In this manner, we combine genetics and environment to describe a model of heat resistance in poultry.Galactooligosaccharides (GOS) that are delivered in ovo improve intestinal microbiota composition and mitigate the negative effects of heat stress in broiler chickens. Hubbard hybrids are slow-growing chickens with a high resistance to heat. In this paper, we determined the impact of GOS delivered in ovo on slow-growing chickens that are challenged with heat. The experiment was a 2 × 2 × 2 factorial design. On day 12 of incubation, GOS (3.5 mg/egg) was delivered into the egg (n = 300). Controls (C) were mock-injected with physiological saline (n = 300). After hatching, the GOS and C groups were split into thermal groups: thermoneutral (TN) and heat stress (HS). HS (30 °C) lasted for 14 days (days 36–50 post-hatching). The spleen (n = 8) was sampled after acute (8.5 h) and chronic (14 days) HS. The gene expression of immune-related (IL-2, IL-4, IL-6, IL-10, IL-12p40, and IL-17) and stress-related genes (HSP25, HSP90AA1, BAG3, CAT, and SOD) was detected with RT-qPCR. Chronic HS up-regulated the expression of the genes: IL-10, IL-12p40, SOD (p < 0.05), and CAT (p < 0.01). GOS delivered in ovo down-regulated IL-4 (acute p < 0.001; chronic p < 0.01), IL-12p40, CAT and SOD (chronic p < 0.05). The obtained results suggest that slow-growing hybrids are resistant to acute heat and tolerant to chronic heat, which can be supported with in ovo GOS administration.

Effects of thermal manipulation of eggs on the response of jejunal mucosae to posthatch chronic heat stress in broiler chickens

In this study, the aim was to investigate effects of chronic heat stress (CHS) on the mRNA levels of proinflammatory cytokines (interleukin [IL]-6, IL-8, IL-1β, and tumor necrosis factor alpha [TNF-α]), toll-like receptors (TLR2 and TLR4), heat shock proteins (Hsp70, heat shock transcription factor [HSF]-1, and HSF3) and antioxidant enzymes (catalase, glutathione peroxidase, NADPH oxidase, and superoxide-dismutase) in the jejunal mucosae of broiler chickens subjected to thermal manipulation (TM) during embryogenesis. TM was carried out at 39°C and 65% relative humidity (RH) for 18 h daily from embryonic days 10 to 18. Control group was incubated at 37.8°C and 56% RH. CHS was induced by raising the temperature to 35°C for 7 D throughout posthatch days 28 to 35. On post-hatch-day 28 (day zero of CHS) and after 1, 3, 5, and 7 D of CHS, the jejunal mucosae were collected from both groups to evaluate the mRNA levels by real-time reverse transcription-PCR analysis. On day zero of CHS, the mRNA levels of antioxidant enzymes, TLRs, HSF3, IL-1β, and TNF-α were not significantly different between TM and control groups, while the levels of IL-6, IL-8, and HSF1 were lower and the level of Hsp70 was higher in TM. However, during CHS, the mRNA levels of antioxidant enzymes, IL-1β, TNF-α, TLR4, and HSF1 were significantly lower in TM than in controls, while the levels of TLR2 and IL-8 were significantly higher in TM than in controls. In addition, TM led to significant increase of mRNA levels of IL-6 and HSF3 after 1 D and Hsp70 after 3 D of CHS and to significant decrease of mRNA levels of IL-6 after 3 and 5 D, HSF3 after 7 D, and Hsp70 after 5 D of CHS. Results of this study suggest that TM led to altered posthatch antioxidant, immunological, and Hsp response to CHS in the jejunal mucosae of broiler chickens, probably indicating that TM may mitigate the adverse effects of CHS.

Quercetin Protects Against Lipopolysaccharide-Induced Intestinal Oxidative Stress in Broiler Chickens through Activation of Nrf2 Pathway.

We investigated the potential ability of quercetin to protect against lipopolysaccharide (LPS)-induced intestinal oxidative stress in broiler chickens and the potential role of the Nrf2 (nuclear factor erythroid 2-related factor 2) signaling pathway. One-day-old broiler chickens (n = 240) were randomized into four groups: saline-challenged broiler chickens fed a basal diet (Con), LPS-challenged broiler chickens on a basal diet (LPS), and LPS-treated broiler chickens on a basal diet containing either 200 or 500 mg/kg of quercetin (Que200+LPS or Que500+LPS). Quercetin (200 mg/kg) significantly alleviated LPS-induced decreased duodenal, jejunal, and illeal villus height and increased the crypt depth in these regions. Quercetin significantly inhibited LPS-induced jejunal oxidative stress, including downregulated reactive oxygen species (ROS), malondialdehyde (MDA), and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels, and it upregulated superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels. Quercetin relieved LPS-induced jejunal mitochondria damage and upregulated mitochondrial DNA copy number-related gene expression, including cytochrome c oxidase subunit 1 (COX1), ATP synthase F0 subunit 6 (ATP6), and NADH dehydrogenase subunit 1 (ND1). Quercetin attenuated the LPS-induced inhibition of Nrf2 activation, translocation, and downstream gene expression, including heme oxygenase-1 (HO-1), NAD (P) H dehydrogenase quinone 1 (NQO1), and manganese superoxide dismutase (SOD2). Additionally, quercetin attenuated the LPS-inhibition of c-Jun N-terminal kinase (JNK), Extracellular Regulated protein Kinases (ERK), and p38MAPK (p38) phosphorylation in the MAPK pathway. Thus, quercetin attenuated LPS-induced oxidative stress in the intestines of broiler chickens via the MAPK/Nrf2 signaling pathway.

Dietary methylsulfonylmethane supplementation and oxidative stress in broiler chickens

Methylsulfonylmethane (MSM) is an organic, sulfur-containing compound widely used as a dietary supplement to improve joint health and treat arthritic pain. An experiment was conducted to study the effects of feeding 0.05% MSM to broilers exposed to diet-induced oxidative stress on tissue MSM distribution, growth performance, oxidative stress biomarkers, and immune responsivity. A total of 528 birds were allocated to 4 dietary treatments (fresh oil-no MSM, fresh oil-MSM, oxidized oil-no MSM, oxidized oil-MSM) as provided ad libitum to 11 replicate cages of 12 birds per treatment. Blood and tissue samples were collected to analyze MSM concentrations, and oxidative stress biomarkers including concentrations of thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), total glutathione, and glutathione peroxidase (GPx) and reductase (GR) activities. Additionally, blood samples collected at day 25 were used to quantify T-cell (TC) populations using flow cytometry. Overall, MSM was quantified in all tissues and plasma samples of MSM-treated groups at all time points. Oxidized oil reduced (P = 0.006) feed intake over the 21-d feeding period, but MSM did not affect growth equally across time points. No effects (P > 0.2) of MSM or oil type were observed on TC populations. In the presence of oxidized oil, MSM reduced (P = 0.013) plasma TBARS and increased (P = 0.02) liver GPx at day 21, and increased (P = 0.06) liver GR at day 7. Irrespective of dietary oil type, groups supplemented with MSM showed higher plasma TAC at day 7 (P = 0.023), liver GPx activity at day 21 (P = 0.003), and liver GR activity at day 7 (P = 0.004) compared with groups not receiving MSM. In conclusion, 0.05% dietary MSM supplementation partially protected birds from oxidative stress but did not affect immune cell profiles.

Effect of mineral and vitamin C mix on growth performance and blood corticosterone concentrations in heat-stressed broilers

Heat stress is a major problem in the poultry industry, especially during summer months and when birds are raised under high-density conditions. Previous studies have reported that vitamin C or electrolyte supplementation could palliate the effects of heat stress in broiler chickens. The present study evaluated the effect of a mineral and vitamin mix (AHS) added to drinking water on the performance of broiler chickens. In total, 1,824 one-day-old birds were randomly allocated to 48 pens. Maximum animal density was 26.5 kg/m2. The control group received no additive; AHS-1 and -2 groups received the AHS mix at a concentration of 1 and 2 kg/1,000 L in drinking water, respectively; and the Vit-C group received vitamin C in drinking water at 200 g/1,000 L. All birds were fed the same diets based on a 3-phase feeding program; feed and water were given on ad libitum basis. To mimic heat stress conditions, temperature in the barn was raised to 35 C from 08:00 to 14:00 h each day. For the overall growing period (0 to 35 D), adding AHS to drinking water increased final BW, ADG, and ADFI linearly (PLinear 0.10). No significant effect on mortality were found (8.77%; P > 0.10). Relative to control, all the treatments tested reduced (P

Evaluation of the hematological and clinical biochemical markers of stress in broiler chickens.

Background and Aim:Stress significantly affects health and productivity of animals. There is need for affordable and easy-to-assay markers of physiological stress in broilers. This study evaluated hematological and serum biochemical markers of physiologic stress in broiler chickens.Materials and Methods:Thirty day-old broiler chickens were assigned to three groups of ten broilers each during the 56-day study. Group 1 broilers served as the control and were not exposed to any stressors; Group 2 broilers were stocked at the stress density of 50 kg BW m–2 from day 49 to 56 while Group 3 broilers had their feed withdrawn 36 h before blood collection on day 56. Blood samples were collected on day 49 (pre-stress sample) and day 56 (post-stress sample) from all the birds and subjected to hematological and serum biochemical analysis.Results:The parameters did not vary significantly (p>0.05) pre-stress. Post-stress, there were significant variations in the heterophil, lymphocyte, and eosinophil counts and in the heterophil to lymphocyte ratio across the three groups. The concentrations of the plasma fibrinogen and serum albumins, sodium, and sodium to potassium ratio of the broilers varied significantly across the groups.Conclusion:Heterophil, eosinophil, and lymphocyte counts, the heterophil to lymphocyte ratio, plasma fibrinogen, serum albumin, sodium, and sodium to potassium ratio are significant markers of physiological stress in broilers.