Heat-stressed Broilers Research Articles

Adaptation to Heat Stress in Broilers Using Dried Tomato Pomace and Zinc: Effects on Growth Performance, Oxidative Stress, Intestinal Features and Humoral Immunity

Adaptation to Heat Stress in Broilers Using Dried Tomato Pomace and Zinc: Effects on Growth Performance, Oxidative Stress, Intestinal Features and Humoral Immunity

The effects of vitamin E on T cell subsets and immunoglobulin-containing plasma cells in the spleen of heat-stressed broiler chickens

iven a bird’s underdeveloped lymph vessels and lymph nodes, the spleen is of the utmost importance in the avian immune system. Broiler chickens can be subjected to heat stress (HS), which causes an increase in mortality, a decrease in feed intake, body weight gain, and hatchability. Vitamin E is an important antioxidant for cells, but there is limited information about how heat stress affects spleen tissue in chickens and how vitamin E can change this effect. Therefore, the aim of this study was to investigate the effects of vitamin E based on the location of subpopulations of T cells and immunoglobulin-producing plasma cells in the spleens of broiler chickens subjected to HS. The results indicated that vitamin E supplementation in the broiler chicken diet could increase the population of immune system cells in heat-stressed chickens. The findings of this study could be used as a reference for the development of management strategies for broiler chickens, especially in countries with a hot climate.

Copper Super-Dosing Improves Performance of Heat-Stressed Broiler Chickens through Modulation of Expression of Proinflammatory Cytokine Genes.

Continuous exposure to high ambient temperatures brings about a number of oxidative damages in chickens. Copper (Cu), an active component of a number of antioxidative defence components, should arrest these changes to take place although that may not be possible under the standard dosing regimen followed by the industry. To ascertain the optimum dose response that may be beneficial in sustaining the performance of chickens under heat stress (HS), broiler chickens (n = 400) were exposed to high ambient temperature (between 27.2°C and 35.3°C) during 1-35 d. Copper (Cu) as Cu proteinate (Cu-P) at concentrations of 37.5, 75, 112.5, and 150 mg/kg was supplemented to the diet. The negative control (NC) diet did not contain any supplemental Cu. Increasing dietary Cu improved (P < 0.001) body weight, feed intake, and conversion ratio. Serum concentrations of total cholesterol at 21 d (P = 0.009), HDL cholesterol at 35 d (P = 0.008), LDL cholesterol at 21 d (P = 0.015), and triacylglycerol at both 21 d (P = 0.033) and 35 d (P = 0.001) decreased as Cu in the diet increased. As Cu in the diet increased, hemoglobin increased (P = 0.003) at 21 d, and the heterophil to lymphocyte ratio decreased both at 21 d (P = 0.047) and 35 d (P = 0.001). Superoxide dismutase and glutathione peroxidase activities increased when dietary Cu increased to 150 mg/kg (P < 0.01). Liver Cu at 35 d increased linearly with the dose of Cu in the diet (P = 0.0001). Selected bacteria were enumerated in the digesta to ascertain if Cu super-dosing affected their population in any way in the absence of any enteric challenge. Escherichia coli and total Salmonella numbers decreased (P = 0.0001), and total Lactobacillus increased (P = 0.0001) proportionately with dietary Cu. Interleukin-6 and tumour necrosis factor-α gene expression increased linearly (P = 0.0001) as Cu in the diet increased though the response plateaued at 112.5 mg/kg. It was concluded from the present experiment that during conditions of impending HS, dietary supplementation of 112.5 to 150 mg Cu/kg diet as Cu-P may be a novel strategy to alleviate the negative effects of HS without involving any apparent risk of Cu toxicity.

Antioxidant status, hematology, performance, organ and carcass evaluation of heat-stressed broiler chickens fed with dietary Bambusa vulgaris leaf meal

Objectives: The objective of this study was to evaluate the inclusion of bamboo leaf meal (BLM) in broiler chicken feed to alleviate heat stress. Materials and Methods: This investigation was conducted following institutional policies guiding the handling of animals as approved for scientific research. 150 heat-stressed Arbor Acres broiler chickens were divided randomly into five dietary treatments, T1–T5, of 30 per treatment and 10 per replicate, to determine the consequence of feeding BLM on health and performance. Birds in T1–T4 were fed 0%, 1%, 1.5%, and 2% BLM-included diets, respectively, while T5 had a 0.2% vitamin C-included diet. Results: Increasing dietary BLM positively impacted body weight gain, feed intake, feed conversion rate (FCR), and stress indices levels. Broiler chickens had better feed intake (267 gm), weight gain (1,504 gm), and FCR (3.64) in T4. Serum glutathione peroxidase and malondialdehyde levels were not statistically different with increasing dietary BLM, while corticosterone levels were lower for chickens fed with dietary BLM. The superoxide dismutase index levels did not follow a particular pattern as dietary BLM increased. The hematology, carcass, and organ quality were unaffected by dietary BLM inclusion. Conclusion: BLM inclusions up to 2% in the broiler diet ameliorate heat stress conditions and improve performance without imposing any detrimental impact on the birds.

Litter quality and incidence and severity of footpad dermatitis in heat stressed broiler chickens fed supplemental zinc

In this study, we evaluated the effect of dietary Zn supplementation on growth performance, serum Zn concentration, litter quality attributes, and occurrence of footpad dermatitis in broiler chickens subjected to chronic heat stress. The study was conducted using a 2 × 2 factorial arrangement of dietary Zn oxide supplementation (0 and 70 mg/kg) and temperature (thermoneutral and chronic heat stress) in a completely randomized design. Five hundred forty-four 1-d-old male broiler chickens were randomly assigned to 4 experimental treatments with 8 replicate pens per treatment having 17 chickens in each replicate pen. Broiler chickens were fed corn-soybean meal-based basal diets for starter (0 to 10 d), grower (10 to 24 d), and finisher (24 to 42 d) growth periods with or without 70 mg/kg supplemental Zn oxide. Growth performance was recorded in terms of body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR). Serum Zn concentration and occurrence of footpad dermatitis were evaluated at d 14, d 28, and d 42 of experiment. Litter quality attributes were measured at d 1 and d 42 of the experiment except ammonia volatilization that was measured at d 28 and d 42 of the experiment. There was no interaction between dietary Zn and temperature for growth performance, serum Zn concentration, litter quality, and occurrence of FPD. Dietary Zn supplementation had no effect on overall growth performance, serum Zn, and litter quality of broiler chickens. However, supplemental Zn reduced the occurrence of footpad dermatitis in broiler chickens at the end of experiment (P < 0.05). Broiler chickens subjected to heat stress had lower overall BWG (P = 0.002) and FI (P = 0.001). Serum Zn concentrations were similar regardless of the temperature. Chronic heat stress increased the litter pH (P = 0.001), moisture (P < 0.001), temperature (P < 0.001) at d 42, and ammonia volatilization at d 28 (P < 0.001) and d 42 (P < 0.001). Incidence and severity of footpad dermatitis was greater in broiler chickens subjected to chronic heat stress (P < 0.01). Findings of our study indicate that heat stress results in poor growth performance and increases the incidence and severity of footpad dermatitis by lowering the litter quality in broiler chickens. In addition, dietary Zn supplementation may lower the occurrence of footpad dermatitis in broiler chickens without affecting the growth performance, serum Zn, and litter quality.

Role of organic selenium in resisting oxidative stress during tropical summer in broiler chicken

The present study was conducted to investigate the effect of selenium supplementation on the oxidative status of hepatic tissue during heat stress in broilers. The study was conducted in two phases, one during autumn and the other during summer with a total of 300 birds. During the first phase, 60 chicks were divided into six replicates with 10 birds in each and during the second phase, 240 chicks were divided into four groups with six replicates containing 10 birds in each. The experimental rations given to different groups were control (Basal ration), HS I (Basal ration), HS II (Basal ration + 0.3 ppm Se, HS III (Basal ration + 0.6 ppm Se) and HS IV (Basal ration + 0.9 ppm Se). Hepatic tissues collected at 21 and 42d were analyzed for oxidative status. HS-induced oxidative stress was revealed by the significant elevation in lipid hydroperoxides, MDA and protein carbonyl levels which in turn triggered the activities of anti-oxidant enzymes, i.e GPx, GST, SOD and G6PD in the hepatic cytosol. The total antioxidant capacity and glutathione concentration were significantly altered due to HS. Selenium at 0.3 ppm was effective in counteracting the oxidative stress at 21d while 0.6 ppm of Se was more effective at 42d. Se supplementation at 0.6 ppm improved the activities of antioxidant enzymes and G6PD. The total antioxidant capacity and GSH concentrations were better improved with 0.6 ppm of Se compared to other treatments.

Resveratrol relieves chronic heat stress-induced liver oxidative damage in broilers by activating the Nrf2-Keap1 signaling pathway

Heat stress (HS) affects poultry production and welfare, causing enormous damage to poultry. Resveratrol, an antioxidant and anti-inflammatory natural plant polyphenol, is widely used in agriculture for the prevention of oxidative stress-related diseases. This study aimed to explore the effects and potential mechanism of resveratrol on liver oxidative damage in heat-stressed broilers. Sixty SPF chickens were randomly divided into control, heat stress (HS) and HS+ resveratrol (resveratrol) groups. Broilers were exposed to 35 ± 2 ℃ (8 h/d) for 7 consecutive days to induce HS, and the other 16 h/d were kept at 23 ± 2 ℃, similar to the control group. Broilers received 400 mg/kg resveratrol in the basic diet 2 days before exposure to HS and for the following 7 days. The results showed that resveratrol improved growth performance by increasing the average daily gain (ADG) and reducing the feed conversion ratio (FCR), compared with the HS group. Heat stress reduced liver weight and index, increased inflammatory cell infiltration in the liver, enhanced serum AST levels, and decreased TP and ALB II levels, which resulted in liver injury in broilers, and resveratrol effectively alleviated liver injury. Moreover, supplementation with resveratrol enhanced the activities of liver antioxidant enzymes resulting in higher GPX and SOD levels than those in the heat-stressed broilers, and decreased MDA levels. Furthermore, resveratrol alleviated liver oxidative stress by activating the gene and protein levels of Nrf2 and HO-1, enhancing NQO1 and SOD1 gene levels, and decreasing protein levels of HSP70, p62, and Keap1, and thereby alleviated the liver injury of heat-stressed broilers. Compared with the HS group, Nrf2 immunofluorescence was significantly up-regulated in the livers of resveratrol group. These results suggest that resveratrol can enhance the liver antioxidant function by activating the Nrf2-Keap1 signaling pathway to promote growth performance in broilers under HS.

Dietary Alpha-Lipoic Acid Effects on The Mitigation of the Negative Impact of Heat Stress in Broilers

Dietary Alpha-Lipoic Acid Effects on The Mitigation of the Negative Impact of Heat Stress in Broilers

Dietary shredded steam-exploded pine particle supplementation as a strategy to mitigate chronic cyclic heat stress by modulating gut microbiota in broilers

Improving the availability of underutilized waste for the economic use of livestock feed can be important in countries where feed grain production is scarce. Modulating the gut microbiota through the fibrous content present in these wastes may help mitigate the adverse effects of heat stress (HS). Here, we investigated the effects of dietary steam-exploded pine particle (SPP), a value-added waste product, on the performance, gut health, and cecum microbiota in heat-stressed broilers. Ross 308 broilers (n = 180) at 29 days of age were distributed into three dietary treatment groups (0%, 1%, and 2% SPP) and two temperature conditions (NT: 21 °C; CHS: 31 °C) and grown for seven days. CHS, but not SPP, adversely affected performance parameters, but SPP did not interactively modulate these results. On the contrary, both differently affected other parameters. CHS resulted in increased rectal temperature, total protein in serum, and Nox4 gene expression, whereas 2% SPP increased GLP-2 and the Nox4 gene expression in the duodenum in comparison to 0% and 1% SPP. CHS significantly modified the beta-diversity of cecal microbiota while 1% SPP supplementation in diets increased the abundance of the favorable bacterial genera in chicken. Concludingly, CHS adversely affects growth performances, gut health, stress-related genes, and cecal microbiota while dietary 1% SPP may facilitate the proliferation of beneficial microorganisms in the cecum of broilers.

Effects of L-serine administration on meat quality, characteristics and mineral content of tibia bone in heat-stressed broiler

in heat-stressed broiler chickens. One hundred and twenty broiler chicks were allocated into four groups of 30 each. Group A (feed restriction), Group B (feed restriction + L-serine), Group C (ad libitum) and Group D (ad libitum + L-serine). Feed restriction (20%) was implemented on days 7–14, and L-serine (200 mg/kg) was provided orally from days 1–14. Seven broiler chickens were slaughtered from each group at 35 days old to determine meat drip loss, cooking loss and pH; and tibia bone weight, length, diameter, weight/length index, robusticity index, strength and proximate analysis. Serum samples were harvested for the determination of calcium and phosphorus concentrations. Temperature-humidity index in the pen (28.72 - 32.90) was above the thermoneutral zone indicating heat stress. The drip loss and cooking loss were lower in FR + L-serine and AL + L-serine groups compared to the controls. The tibia bone weight, length, weight/length index and breaking force were higher (P &lt; 0.05) in FR + L-serine and AL + L-serine groups compared to the controls. The percentage composition of ash, calcium and phosphorus was relatively high in L-serine-administered groups. In conclusion, L-serine improved meat quality and tibia bone characteristics in broiler chickens exposed to heat stress

Transcriptome and metabolome analyses reveal the regulatory effects of compound probiotics on cecal metabolism in heat-stressed broilers

The effect of compound probiotics on the caecum of broilers under heat stress was assessed in this study. A total of 400 twenty-eight-day-old AA male broilers were randomly divided into 4 treatment groups, where each group had 5 replicates of 20 broilers. The 4 treatment groups were a heat stress control group (broilers receiving a normal diet) and groups HP I, HP II, and HP Ⅲ, consisting of broilers receiving 1, 5, and 10 g of compound probiotics added to each kilogram of feed, respectively. Compound probiotics (L. casei, L. acidophilus, and B. lactis at a ratio of 1:1:2) were used to formulate a compound probiotic powder, with 1×1010 CFU/g of effective viable bacteria. Heat stress treatment was performed at 32 ± 1°C from 9:00 to 17:00 every day from 28 d to 42 d. In d 28 to 42, compared with the HC group, the ADG of broilers in the HP II and III groups was significantly increased (P < 0.05); the ADFI difference between groups was not significant (P > 0.05); the FCR of HP II and III broilers was significantly decreased (P < 0.05); and the FCR of the HP I group increased, but the difference was not significant (P > 0.05). Transcriptome results demonstrate that 665 differential genes were screened (DEGs; upregulated: 366, downregulated: 299). The DEGs were enriched in the B cell receptor signaling pathway, the intestinal immune network for IgA synthesis, the Fc epsilon RI signaling pathway, and other signaling pathways, according to KEGG enrichment analysis. Metabolome analysis identified 92 differential metabolites (DAMs; upregulated: 48, downregulated: 44). KEGG enrichment analysis indicated significant enrichment of Pantothenate and CoA biosynthesis and beta-Alanine metabolism. The combined transcriptome and metabolome analysis revealed that the DAMs and DEGs were mostly involved in beta-alanine metabolism, arginine biosynthesis, amino sugar and nucleotide sugar, and alanine, aspartate, and glutamate metabolism. The results of this study suggest that the addition of compound probiotics has a positive effect on intestinal metabolites, improving the growth performance and contributing to the overall health of broilers under heat stress.

Development of Heat Stress Forecasting System in Mechanically Ventilated Broiler House Using Dynamic Energy Simulation

The internal rearing environment of livestock houses has become an important issue in the last few years due to the rapid increase in meat consumption. As the number of days of heat waves increase continuously, problems caused by abnormal weather changes steadily occurred. Thus, the main goal of this study is to develop a technology that can automatically calculate heat stress for livestock by considering weather forecast data. Specifically, a web-based heat stress forecasting system for the evaluation of heat stress in broilers was developed. The field experiments were carried out at the selected broiler house to measure and analyze the external weather, the internal environment, and the ventilation flow rate of fans used in tunnel ventilation. The developed model was validated by comparing the field and simulated thermal environment values. Based on a reliable model, Land-Atmosphere Modeling Package (LAMP) weather forecast data was used to show the stress index on the internal rearing environment with a heat stress index suitable for South Korea. When the users input the farm location, structure and equipment, and rearing information, users responded after receiving heat stress from the broiler raised in a mechanically ventilated broiler house.

Dietary supplementation with synbiotics improves growth performance, antioxidant status, immune function, and intestinal barrier function in broilers subjected to cyclic heat stress.

This study investigated the effects of synbiotics supplementation on growth performance, antioxidant status, immune function, and intestinal barrier function in broilers subjected to cyclic heat stress. One hundred and forty-four 22-day-old male broilers were randomly assigned to one of three treatment groups of six replicates each for a 21-day study, with eight birds per replicate. Broilers in the control group were reared at a thermoneutral temperature and received a basal diet. Broilers in the other two heat-stressed groups were fed a basal diet supplemented without (heat-stressed group) and with 1.5g/kg synbiotic (synbiotic group). One and a half gram of the synbiotic consisted with 3 × 109 colony forming units (CFU) Clostridium butyricum, 1.5 × 109CFU Bacillus licheniformis, 4.5 × 1010CFU Bacillus subtilis, 600mg yeast cell wall, and 150mg xylooligosaccharide. Compared with the control group, heat stress increased rectal temperatures at 28, 35, and 42days of age, respectively (P < 0.05). Birds subjected to heat stress had reduced weight gain, feed intake, and feed efficiency during 22 to 42days (P < 0.05). In contrast, supplementation with the synbiotic decreased rectal temperature at 42days of age and elevated weight gain of heat stress-challenged broilers (P < 0.05). Heat-stressed broilers exhibited a lower superoxide dismutase (SOD) activity in jejunal mucosa and a higher malondialdehyde accumulation in serum, liver and jejunal mucosa (P < 0.05), and the regressive SOD activity was normalized to control level when supplementing synbiotic (P < 0.05). Heat stress increased interleukin-1β (IL-1β) and interferon-γ (IFN-γ) levels in serum and IL-1β content in jejunal mucosa of broilers (P < 0.05). Synbiotic reduced IL-1β level in serum of broilers subjected to heat stress (P < 0.05). Compared with the control group, elevated serum diamine oxidase activity and reduced jejunal villus height were observed in broilers of the heat-stressed group (P < 0.05), and the values of these two parameters in the synbiotic group were intermediate (P > 0.05). Heat stress upregulated mRNA abundance of IL-1β and IFN-γ and downregulated gene expression levels of occluding and zonula occluden-1 (ZO-1) in jejunal mucosa of broilers (P < 0.05). The alterations in the mRNA expression levels of jejunal IL-1β and ZO-1 were reversed by the synbiotic (P > 0.05). In conclusion, dietary synbiotics could improve growth performance, antioxidant capacity, immune function, and intestinal barrier function in heat-stressed broilers.

Coping heat stress by crushed fennel (Foeniculum vulgare) seeds in broilers: Growth, redox balance and humoral immune response

The goal of this study was to determine how fennel seed supplementation affected broiler growth, carcass quality, antioxidant status, and antibody titre in heat stressed broilers. A total of 720 one day-old broiler chickens were weighed and assigned to 28 floor pens (25 broiler chickens per pen). The broiler chickens were housed in a thermoneutral (TN) environment and were exposed to heat stress (HS). For 23 h, the broiler chickens were kept under fluorescent lighting. For 35d, HS broiler chickens were fed a control diet and three levels of fennel seeds powder at rates of 15g/kg (Fen-15), 20 g/kg (Fen-20), and 25 g/kg (Fen-25). Overall feed intake, weight gain, and dressing % were considerably greater (P < 0.05) in Fen-25 and TN, but FCR was significantly reduced (P<0.01) in the same groups. When TN, Fen-20, and Fen-25 were compared to the control, malanodialdehyde (MDA), paraoxonase (PON1), and antibody titre against New Castle disease (ND) were considerably (P < 0.05) greater. Further, linear and quadratic response was for feed intake, weight gain, FCR, MDA, PON1 and ND titre. It was concluded that Fen-20 and Fen-25 increased broiler growth, carcass quality, antioxidant status, and immunological response under HS conditions.

WGCNA Analysis of Important Modules and Hub Genes of Compound Probiotics Regulating Lipid Metabolism in Heat-Stressed Broilers.

Simple SummaryIn recent years, the high frequency of high-temperature weather has dramatically increased the possibility of heat stress. Heat stress can affect broilers’ production performance, fat deposition and meat quality through the cells, tissues and organs. The effect of heat stress on fat deposition and meat quality significantly affects the production efficiency of broilers. Probiotics as feed additives can alleviate the adverse reactions of heat stress. Compound probiotics (Lactobacillus casei, Lactobacillus acidophilus and Bifidobacterium) are all colonized in the gut of broilers and are common probiotic supplements. Weighted gene co-expression analysis technology can closely connect the transcriptome with the lipid metabolism results to find the related genes that act on a specific eigenvalue. The purpose of this study was to study the effects of compound probiotics on production performance, meat quality and lipid metabolism in heat-stressed broilers through weighted gene co-expression analysis to determine the genes and modules related to lipid metabolism and to provide a theoretical basis for the poultry industry to alleviate heat stress.This study aimed to study compound probiotics’ (Lactobacillus casei, Lactobacillus acidophilus and Bifidobacterium) effects on production performance, lipid metabolism and meat quality in heat-stressed broilers. A total of 400 one-day-old AA broilers were randomly divided into four groups, each containing the same five replicates, with 20 broilers in each replicate. The control (21 °C) and experiment 2 were fed a basic corn–soybean meal diet. Experiment 1 (21 °C) and experiment 3 were fed a basic corn–soybean meal diet with 10 g/kg compound probiotics on days 7 and 28, respectively. The ambient temperature of experiment 2 and experiment 3 was increased to 30–32 °C (9:00–17:00) for 28–42 days, while the temperature for the other time was kept at 21 °C. The results showed that, compared with the control, the production performance and the content of high-density lipoprotein cholesterol in experiment 1 and triglyceride (TG) in experiment 2 increased (p < 0.05). Compared with experiment 2, TG decreased and the production performance increased in experiment 3 (p < 0.05). However, there was no significant change in meat quality indicators. Weighted gene co-expression network analysis (WGCNA) was used to analyze the intramuscular fat, abdominal fat and five blood lipid indicators. We found five related modules. Fatty acid biosynthesis, glycerolipid metabolism, and fat digestion and absorption were the pathways for KEGG enrichment. Additionally, NKX2-1, TAS2R40, PTH, CPB1, SLCO1B3, GNB3 and AQP7 may be the hub genes of compound probiotics regulating lipid metabolism in heat-stressed broilers. In conclusion, this study identified the key genes of compound probiotics regulating lipid metabolism and provided a theoretical basis for the poultry breeding industry to alleviate heat stress.

Effects of brown seaweed products on growth performance, plasma biochemistry, immune response, and antioxidant capacity of broiler chickens challenged with heat stress

Brown seaweed (Ascophyllum nodosum) is an exceptional bioactive substance known for its excellent antioxidant ability. Given the potential benefits of brown seaweed, the current study was conducted to determine its efficacy on growth performance, blood biochemistry, immunoglobulins (IgG and IgM), and the antioxidant capacity of broiler chickens challenged with heat stress (HS). A total of 336 mixed-sex Ross 308 broiler chicks (one-day-old) were randomly assigned into two groups; The thermoneutral group (TN, broilers were raised at 24 ± 1°C); and the heat stress group (HS; broilers were exposed to 32°C to 34°C, 8 h/d from day 21 to 27; the temperature in the remaining time was same as TN group). All birds in each group were randomly allotted to 4 dietary treatments—Negative control (NC) (without seaweed), NC + 1 mL seaweed extract (SWE) in drinking water, NC + 2 mL SWE in drinking water, and NC + 2% seaweed meal (SWM) in feed. Each treatment was assigned to six replicates with 7 broilers/replicate. Average body weight gain (ABWG), average feed intake (AFI), average water intake (AWI), feed conversion ratio (FCR), and mortality were determined weekly. On day 28, two male birds/cage were euthanized to collect blood and immune organs for subsequent biochemical, antioxidant, and immune status analysis. Data were analyzed as a 4 × 2 factorial analysis of variance using the GLM procedure of Minitab software. Overall, 2% SWM inclusion significantly increased (P < 0.05) the AFI, ABWG, and AWI of broiler chickens irrespective of HS. HS significantly reduced (P < 0.05) AFI and increased (P < 0.05) the bird's rectal temperature, plasma concentrations of sodium, chloride, glucose, amylase, and uric acid compared to TN birds. HS increased (P < 0.05) serum IgM and IgG and decreased plasma glutathione reductase and glutathione peroxidase compared to TN birds, while the activity of superoxide dismutase was not affected by HS and dietary treatments. 1 mL SWE in water and 2% SWM in feed significantly reduced (P < 0.05) the plasma activity of alanine aminotransferase and gamma-glutamyl transferase of heat-stressed broilers, respectively compared to other treatments. Conclusively, dietary supplementation of brown seaweed improved the growth performance of birds irrespective of HS and may help to reduce the negative effects of HS by improving the plasma enzyme activities of heat-stressed birds.

L-serine improves lipid profile, performance, carcass weight and intestinal parameters in feed restricted broiler chickens during the hot-dry season.

The study evaluated effects of L-serine on lipid profile, performance, carcass weight and small intestinal parameters in heat-stressed broiler chickens subjected to feed restriction. Broiler chickens were divided into four groups, comprising 30 each. Group 1, feed restriction (FR); Group 2, feed restriction + L-serine (200mg/kg) (FR + L-serine); Group 3, ad libitum (AL); Group 4, ad libitum + L-serine (200mg/kg) (AL + L-serine). L-serine was administered orally from days 1 to 14, and feed restriction was performed on days 7-14. Serum harvested from blood samples on days 21, 28 and 35 was evaluated for lipid profile. Feed and water intake, live weight gain, organ and carcass weight were measured. At 35days old, broiler chickens (n = 7) per group were sacrificed to evaluate small intestinal morphology. Temperature-humidity index in the pen (30.88 ± 0.81) was above thermoneutral zone, indicating that chickens were subjected to heat stress. Concentrations of low-density lipoprotein, total cholesterol and total triglycerides were lower (p < 0.05), while higher concentration of high-density lipoprotein was recorded in L-serine groups than in the controls. Feed intake and live weight gain on day 35 in L-serine groups were higher (p < 0.05) than in controls. In L-serine groups, liver, spleen, pancreas and heart weight were higher, but abdominal fat was lower than in FR and AL groups. Villus height:crypt height ratio and area of villus surface were highest in L-serine groups than any other group. In conclusion, L-serine decreased low-density lipoprotein, increased feed intake, live weight, organ and carcass weight, villus height:crypt height ratio and villus surface area.

Mitigating heat stress in broilers by dietary dried tamarind (Tamarindus indica L.) pulp: Effect on growth and blood traits, oxidative status and immune response

The objective of the present study was to evaluate the effect different levels of dried pulp of tamarind (DTSP) on growth, lipid profile, oxidative status and immune response in broilers exposed to cyclic heat stress (HS). A total of 720 one-d-old male broiler chickens (Hubbard) were randomly allocated to 6 treatments (5 replicates) consisted of thermoneutral (TN) and HS. In this experiment, 4 groups of broilers under HS condition were fed four levels of dried tamarind seeds pulp (DTSP) powder at the rate of 0 (DTSP), 5 (DTSP-5), 7.5 (DTSP-7.5), 10 (DTSP-10) and 12.5 (DTSP-12.5) g/kg of feed for 35 d of age. Body weight and feed conversion ratio (FCR) increased (p < 0.05) in the TN and DTSP fed broilers. Blood concentration of paraoxonase-1 (PON1) was higher (p < 0.05) in TN and DTSP-10 and DTSP-12.5. However, antibody titer against Newcastle disease (ND) was higher (p < 0.05) in TN, DTSP-7.5, DTSP-10 and DTSP-12.5. Blood cholesterol and triglyceride were lower (p < 0.05) in TN, DTSP-7.5, DTSP-10 and DTSP-12.5. However, blood HDL was higher (p < 0.05) in DTSP-10 and DTSP-12.5. Blood LDL was significantly lower in DTSP-7.5, DTSP-10 and DTSP-12.5. Significantly higher total leucocytes count (TLC) was found in TN and DTSP-12.5; however, heterophils were significantly lower in the same group. In contrast, lymphocytes increased (p < 0.05) in TN, DTSP-7.5, DTSP-10 and DTSP-12.5, while monocytes was significantly decreased in the same group. In conclusion, DTSP improved growth, cholesterol profile, PON1 and leucocytes count and immune response against ND in broilers exposed to heat stress.

Assessment of malondialdehyde level in broiler chickens suffering from chronic heat stress and fed on a diet supplemented with bioactive substances

Heat stress is one of the most important health dilemmas that faces poultry industry characterized by high degrees of economic losses. The presented work, here, was carried out to evaluate the effects of grape pomace (GP) on decreasing the levels of oxidative stress induced by heat stress in broilers. For that purpose, 150 chicks were randomly assigned into three groups (50 chicks/group). One group received no treatment, the control group (G1). The second group (G2) was provided with 25 gm (2.5%) of GP/kg of ration. The third group (G3) was given 50 gm (5%) of GP/kg of ration. The results indicated that the levels of MDA in fresh meat samples (G3) were significantly (p˂0.05) the lowest than those from other meat samples of the G2 and G1. Frozen meat samples (G2 and G3) had significantly (p˂0.05) lesser levels of MDA than those from G1. In the case of MDA from the plasmas of chickens, their levels were significantly (p˂0.05) the lowest in the G3 followed by G2 than those from other plasma samples of G1.

Effects of Dietary Supplementation of Solubles from Shredded, Steam-Exploded Pine Particles on the Performance and Cecum Microbiota of Acute Heat-Stressed Broilers.

Heat stress (HS) negatively influences livestock productivity, but it can be, at least in part, mitigated by nutritional interventions. One such intervention is to use byproducts from various sources that are likely to be included in the consumer chain. Thus, the present study investigated the effects of dietary supplementation of solubles from shredded, steam-exploded pine particles (SSPPs) on the performance and cecum microbiota in broilers subjected to acute HS. One-week-old Ross 308 broilers (n = 108) were fed 0%, 0.1%, or 0.4% SSPP in their diets. On the 37th day, forty birds were allocated to one of four groups; namely, a group fed a control diet without SSPPs at thermoneutral temperature (NT) (0% NT) and acute heat-stressed birds with 0% (0% HS), 0.1% (0.1% HS), and 0.4% (0.4% HS) SSPP-supplemented diets. The NT was maintained at 21.0 °C, while the HS room was increased to 31 °C. The final BW, percent difference in body weight (PDBW), and feed intake (FI) were lower in HS birds, but PDBW was reversely associated with dietary SSPP. Similarly, HS birds had a higher rectal temperature (RT) and ΔT in comparison to birds kept at NT. The FI of SSPP-supplemented birds was not significant, indicating lower HS effects. Plasma triglyceride was decreased in HS birds but not affected in 0.1% HS birds in comparison to 0% NT birds. OTUs and Chao1 were increased by 0.1% HS compared to 0% NT. Unweighted Unifrac distances for 0.1% HS were different from 0% NT and 0.4% HS. The favorable bacterial phylum (Tenericutes) and genera (Faecalibacterium and Anaerofustis) were increased, while the pathogenic genus (Enterococcus) was decreased, in SSPP-supplemented birds. In sum, production performances are negatively affected under acute HS. Dietary supplementation of SSPPs is beneficial for improving community richness indices and unweighted Unifrac distances, and it enhanced the advantageous bacterial phyla and reduced virulent genera and triglyceride hydrolysis in acute HS broilers. Our results indicate that dietary SSPPs modulates the microbial profile of the cecum while resulting in relatively less weight loss and lower rectal temperature compared to control.