Depression of leukocyte protein synthesis, immune function and growth performance induced by high environmental temperature in broiler chickens

Feeding Eucommia ulmoides extract enhances protection against high-temperature stress in chicks

Chick's susceptibility to heat stress often leads to growth retardation, immune function impairment, disease, and mortality. This thesis explores the potential ameliorative effect of 0.8% Eucommia ulmoides extract (EUE) into the diet of heat-stressed chicks in a 15-d feeding trial. The investigation reveals that feeding EUE significantly enhances the BW, ADG, AFI, and F/G of chicks experiencing heat stress. Additionally, the EUE groups exhibited higher levels of T-AOC (at 7 and 15d), SOD (at 15 d), GSH-Px (at 15 d), as well as lower MDA concentrations (at 7 and 15d) in chick serum. Pathological changes and H&E staining revealed that EUE effectively improved tissue damage in the duodenum, heart, and stomach induced by heat stress in the chicks. The EUE groups also showed higher levels of IgA (at 7 d), IgG and IgM (at 7 and 15 d). RNA-seq and WGCNA analysis revealed that EUE mitigates cellular damage and losses in heat-stressed chicks primarily through pathways involving signal transduction, protein synthesis and degradation, as well as cell cycle regulation, particularly the latter. This investigation serves as a fundamental and cognitive framework for the development and application of Eucommia ulmoides feed additives aimed at safeguarding the well-being of chicks in adverse environmental conditions.

LG, Cruz-Neto AP. Combined effects of ambient temperature and food availability on induced innate immune response of a fruit-eating bat (Carollia perspicillata)

Resilience of mammals to anthropogenic climate and land-use changes is associated with the maintenance of adequate responses of several fitness-related traits such as those related to immune functions. Isolated and combined effects of decreased food availability and increased ambient temperature can lead to immunosuppression and greater susceptibility to disease. Our study tested the general hypothesis that decreased food availability, increased ambient temperature and the combined effect of both factors would affect selected physiological and behavioral components associated with the innate immune system of fruit-eating bats (Carollia perspicillata). Physiological (fever, leukocytosis and neutrophil/lymphocyte ratio) and behavioral (food intake) components of the acute phase response, as well as bacterial killing ability of the plasma were assessed after immune challenge with lipopolysaccharide (LPS: 10 mg/kg) in experimental groups kept at different short-term conditions of food availability (ad libitum diet or 50% food-deprived) and ambient temperature (27 and 33°C). Our results indicate that magnitude of increase in body temperature was not affected by food availability, ambient temperature or the interaction of both factors, but the time to reach the highest increase took longer in LPS-injected bats that were kept under food restriction. The magnitude of increased neutrophil/lymphocyte ratio was affected by the interaction between food availability and ambient temperature, but food intake, total white blood cell count and bacterial killing ability were not affected by any factor or interaction. Overall, our results suggest that bacterial killing ability and most components of acute phase response examined are not affected by short-term changes in food availability and ambient temperature within the range evaluated in this study, and that the increase of the neutrophil/lymphocyte ratio when bats are exposed to low food availability and high ambient temperature might represent an enhancement of cellular response to deal with infection.

Early Feeding Strategy Mitigates Major Physiological Dynamics Altered by Heat Stress in Broilers

Heat stress is one of the stressors that negatively affect broiler chickens, leading to a reduction in production efficiency and profitability. This reduction affects the economy in general, especially in hot and semi-hot countries. Therefore, improving heat tolerance of broiler chicks is a key to sustained peak performance, especially under adverse environmental heat stress conditions. The present study investigated three early feed withdrawal regimes (FWD) as a potential mitigation for thermal stress exposure. A total of 240 unsexed one-day-old Cobb-500 chicks were randomly recruited to one of four experimental groups using a completely randomized design (10 birds × 6 replicates). The experimental groups included the control group with no feed withdrawal (control), while the other three groups were subjected to early feed withdrawal for either 24 h on the 5th day of age (FWD-24), 12 h on the 3rd and 5th day of age (FWD-12), or 8 h on the 3rd, 4th, and 5th day of age (FWD-8), respectively. Production performance was monitored throughout the experiment. Meanwhile, blood and liver samples were taken at the end of the experimental period to evaluate major physiological dynamic changes. Our findings demonstrated that under chronic heat stress conditions, FWD treatments significantly improved broilers' production performance and enhanced several physiological parameters compared with the control. Serum levels of thyroid hormones were elevated, whereas leptin hormone was decreased in FWD groups compared with the control. Moreover, serum total protein, globulin, and hemoglobin levels were higher, while total cholesterol and uric acid were lower in the FWD groups. Furthermore, FWD groups showed significantly higher antioxidant marker activity with a significantly lower lipid peroxidation level. Immunoglobulin levels, lysozyme, complement factor C3, and liver heat shock protein 70 (HSP70) concentration were also elevated in FWD compared with the control. Also, serum interleukin-1β (IL-1β) and interferon-gamma (IFN-γ) significantly increased with FWD. Based on our findings, early feed withdrawal can be applied as a promising non-invasive nutritional strategy for broilers reared under chronic heat stress conditions. Such a strategy promotes the alleviation of the deleterious effects of heat stress on broiler performance, immunity, and redox status, owing to the onset of physiological adaptation and the development of thermotolerance ability.

Quantitative Proteomics Reveals Manganese Alleviates Heat Stress of Broiler Myocardial Cells via Regulating Nucleic Acid Metabolism

Heat stress threatens severely cardiac function by caused myocardial injury in poultry. Our previous study has showed that manganese (Mn) has a beneficial effect on heat-stress resistance of broiler. Therefore, we tried to confirm the alleviation mechanism through proteomic analysis after heat stress exposure to primary broiler myocardial cells pretreated with Mn. The experiment was divided into four groups: CON group (37 °C, cells without any treatment), HS group (43 °C, cells treatment with heat stress for 4 h), HS+MnCl2 group (cells treated with 20 μM MnCl2 before heat stress), and HS+Mn-AA group (cells treated with 20 μM Mn compound amino acid complex before heat stress). Proteome analysis using DIA identified 300 differentially expressed proteins (DEPs) between CON group and HS group; 93 and 121 DEPs were identified in inorganic manganese treatment group and organic manganese treatment group, respectively; in addition, there were 53 DEPs identified between inorganic and organic manganese group. Gene Ontology (GO) analysis showed that DEPs were mainly involved in binding, catalytic activity, response to stimulus, and metabolic process. DEPs of manganese pretreatment involved in a variety of biological regulatory pathways, and significantly influenced protein processing and repair in endoplasmic reticulum, apoptosis, and DNA replication and repair. These all seem to imply that manganese may help to resist cell damage induced by heat stress by regulating key node proteins. These findings contribute to a better understanding of the effects of manganese on overall protein changes during heat-stress and the possible mechanisms, as well as how to better use manganese to protect heart function in high temperature.

Protective influence of supplementary betaine against heat stress by regulating intestinal oxidative status and microbiota composition in broiler chickens

To assess the impact of supplementing betaine (BT) under heat stress (HS) conditions on broiler performance and intestinal health from 21 to 42 days of age, a total of 150 male Ross 308 broilers were indiscriminately allotted to 3 treatments with 10 replications of 5 birds each. The control (CON) group was given a basal ration and accommodated at a thermoneutral condition (22 ± 1 °C), whereas the HS and HS + BT groups were raised under cyclic HS (33 ± 1 °C for 8 h and 22 ± 1 °C for 16 h per day) and received the basal ration without or with 1000 mg/kg BT, respectively. The HS reduced average daily gain (ADG); average daily feed intake; villus height (VH); VH to crypt depth (CD) ratio (VCR); activities of trypsin, lipase, glutathione peroxidase (GPX), and catalase; and enumeration of Lactobacillus and Bifidobacterium (P < 0.05) and augmented feed conversion ratio (FCR), CD, malondialdehyde (MDA) accumulation, and enumeration of Escherichia coli, Clostridium, and coliforms (P < 0.05). Conversely, BT supplementation heightened ADG, VH, VCR, trypsin activity, GPX activity, and populations of Lactobacillus and Bifidobacterium (P < 0.05) and lowered FCR, MDA accumulation, and Clostridium population (P < 0.05). Furthermore, the FCR value, trypsin and GPX activities, MDA content, and Bifidobacterium and Clostridium populations in the HS + BT group were nearly equivalent to those in the CON group. To conclude, feeding BT under HS conditions could improve broiler performance through improving intestinal health by specifically mitigating oxidative damage and enhancing the colonization of beneficial bacteria.

Appropriate Genetic Approaches for Heat Tolerance and Maintaining Good Productivity in Tropical Poultry Production: A Review

Heat stress is a major environmental threat to poultry production systems, especially in tropical areas. The effects of heat stress have been discovered in several areas, including reduced growth rate, reduced egg production, low feed efficiency, impaired immunological responses, changes in intestinal microflora, metabolic changes, and deterioration of meat quality. Although several methods have been used to address the heat stress problem, it persists. The answer to this problem can be remedied sustainably if genetic improvement approaches are available. Therefore, the purpose of this review article was to present the application of different approaches to genetic improvement in poultry in the hope that users will find suitable solutions for their poultry population and be able to plan future poultry breeding programs.

Effect of dietary supplemental vitamin C and betaine on the growth performance, humoral immunity, immune organ index, and antioxidant status of broilers under heat stress

Heat stress (HS) has become one of the important factors affecting the development of animal husbandry. The purpose of this experiment was to investigate whether vitamin C (Vc) and betaine (Bet) improve immune organ index and humoral immunity by enhancing the antioxidant status of immune organs, thus protecting broilers from HS-induced injuries. A total of 200 28-day-old Ross 308 broilers were randomly assigned into 5 groups (n = 4 replicates/group, 10 broilers/replicate) which were reared at different ambient temperatures (24 ± 1°C or 33 ± 1°C). The control group fed basal diet, while high-temperature groups were either fed a basal diet (HS group) or a basal diet supplemented with 250-mg Vc/kg diet (HSVc group), 1000-mg Bet/kg diet (HSBet group), and 250-mg Vc plus 1000 mg Bet/kg diet (HSVcBet group), respectively. On day 42, growth performance, humoral immune function, immune organ index, and antioxidant capacity were measured. HS reduced the productive performance of broilers, antibody potency against the Newcastle disease virus (NDV) and sheep red blood cells (SRBC), indices of thymus and bursa, and antioxidant capacity of immune organs. Adding Vc alone or in combination with Bet improved performance, NDV and SRBC antibody potency, thymus and bursa indices, and antioxidant capacity of immune organs in heat-stressed broilers, with the most effective being combination. In summary, HS reduces the antioxidant capacity and immune organ development status of broiler immune organs. Vc and/or Bet can improve the development of immune organs and restore part of the production performance by regulating the antioxidant status of immune organs, among which the combined addition of Vc and Bet has the best effect.

Effects of anti-stress agents on the growth performance and immune function in broiler chickens with vaccination-induced stress

The aim of this study was to evaluate the effects of anti-stress agents on the growth performance and immune function of broilers under immune stress conditions induced by vaccination. A total of 128, 1-day-old Arbor Acres broilers were randomly divided into four groups. Group normal control (NC) was the control group. Group vaccination control (VC), T 0.5%, and T 1% were the treatment groups, which were nasally vaccinated with two doses of the Newcastle disease virus (NDV) vaccine. The chicks in groups T 0.5% and T 1% were fed conventional diets containing 0.5% and 1% anti-stress agents. Thereafter, these broilers were slaughtered on 1, 7, 14, and 21 days post-vaccination. The results indicated that anti-stress agents could significantly reduce serum adrenocorticotropic hormone (ACTH) (P < 0.01) and cortisol (CORT) (P < 0.05) levels, and improve the growth performance (P < 0.05) and immune function of broilers (P < 0.05); However, the levels of malondialdehyde (MDA) (P < 0.05) were decreased, and the decreased total antioxidant capacity (T-AOC) (P < 0.01) levels mediated by vaccination were markedly improved. In addition, anti-stress agents could attenuate apoptosis in spleen lymphocytes (P < 0.01) by upregulating the ratio of Bcl-2 to BAX (P < 0.01) and downregulating the expression of caspase-3 and -9 (P < 0.01), which might be attributed to the inhibition of the enzymatic activities of caspase-3 and -9 (P < 0.05). In conclusion, anti-stress agents may improve growth performance and immune function in broilers under immune-stress conditions.RESEARCH HIGHLIGHTS Investigation of effects and mechanism of immune stress induced by vaccination.Beneficial effect of anti-stress agents on growth performance, immune function, oxidative stress, and regulation of lymphocyte apoptosis.Demonstration of the effects of apoptosis on immune function in the organism.

Placental Development and Physiological Changes in Pregnant Ewes in Silvopastoral and Open Pasture Systems during the Summer

This study aimed to analyze the reproductive and physiological changes in ewes subjected to heat stress during pregnancy at UTFPR-Brazil. Twenty-four pregnant crossbred ewes were kept in a silvopastoral system (SP) or an open pasture system (OP) throughout the final trimester of pregnancy. Both systems were stressful, but the SP system had lower air temperature than the OP system (26.0 ± 0.38 and 26.9 ± 0.41 °C, respectively; p = 0.0288). Moreover, the radiant thermal load of the two groups presented a difference of 34 Wm^-2 (p = 0.0288), and the grass temperature was also lower in the SP system compared to that in the OP system (23.4 ± 0.37 and 25.6 ± 0.44 °C, respectively; p = 0.0043). The respiratory and heart rates of animals from the OP group were higher than those from the SP group (p < 0.001), but no difference was observed in the mobilization of white blood cells (p = 0.4777), and the neutrophil count was only affected by time (p < 0.0001). As regards placental biometry, placentas in twin pregnancies had a greater membrane area (p = 0.0223), but no differences between the systems were observed in placental weight (p = 0.1522) and the number of cotyledons (p = 0.5457). We concluded that the type of rearing system used affects the thermal comfort of pregnant ewes, and that an SP system can offer more amenable microclimatic conditions, which result in greater comfort for the ewes.

Dietary Corn Silk (Stigma maydis) Extract Supplementation Modulate Production Performance, Immune Response and Redox Balance in Corticosterone-Induced Oxidative Stress Broilers

Immunosuppression is a serious consequence of oxidative stress exposure that negatively affects the productivity and profitability of birds, as well as their well-being. Thus, the present investigation was designed to evaluate the potential of corn silk extract (CSE) supplementation to overcome the negative impacts of oxidative stress induced by corticosterone administration (CORT) in broiler chickens. A total of 280 one day old Cobb 500 male chicks were divided into four groups in 2 × 2 factorial arrangements. The experimental groups included CSE supplementation (0 or 500 mg/kg diet, from 20 to 35 days of age) and CORT administration (0 or 25 mg/kg diet, from 22 to 35 days of age) as independent factors. At the end of week five of age, production performance parameters were measured. The humoral and cell-mediated immune response parameters, redox status, and stress markers were determined. Data revealed deleterious effects of CORT administration on the broilers' body weight, body weight gain, and feed conversion ratio. Moreover, an exponential increase in stress marker levels, in addition to immunosuppression and redox imbalance, were associated with CORT administration. However, CSE supplementation, with its high total phenols content, partially alleviated the negative impacts of CORT administration, as shown by a significant improvement in immune response parameters and antioxidant activity, as well as a reduction in stress marker levels. Furthermore, CSE supplementation to non-stressed birds even significantly improved total antioxidant activity, total white blood cells (TWBCs) count, T-lymphocyte stimulating index, and wattle thickness. It can be concluded that, under stress conditions in commercial broiler farms, dietary CSE supplementation can strongly be recommended to modulate the negative impacts of stress. Therefore, CSE can be used as an effective immunomodulator and antioxidant agent to increase commercial broiler farm productivity and profitability.

Protective Effect of Manganese on Apoptosis and Mitochondrial Function of Heat-Stressed Primary Chick Embryonic Myocardial Cells

Heat stress, as a kind of oxidative stress, induces cell apoptosis. Apoptosis is a form of programmed cell death, and mitochondria play an important role in apoptosis. Manganese (Mn) has an antioxidant capacity by enhancing the activity of manganese superoxide dismutase (MnSOD). To investigate the potential effect of Mn on heat stress-induced apoptosis and mitochondrial function, we examined crucial related factors in the context of heat stress using primary chick embryonic myocardial cells pretreated with Mn for 24 h. The results showed that Mn restored the heat stress-induced decrease in cell viability and reduced the activities of caspase-3 (P < 0.05). The repression of the Δψm and intracellular ATP content caused by heat stress was reversed dramatically in the Mn pretreatment group (P < 0.05). Additionally, Mn inhibited heat stress-induced mitochondrial fission, as shown by decreased mitochondrial fission-related protein dynamin-related protein 1 (Drp1) expression and increased mitochondrial fusion-related protein optic atrophy 1 (Opa1) and mitofusin 1 (Mfn1) (P < 0.05) in primary chick embryonic myocardial cells. It was concluded that Mn attenuates the mitochondrial-mediated apoptosis pathway and sustains mitochondrial structure and function under heat stress in primary chick embryonic myocardial cells.

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 (200 mg/kg) (FR + L-serine); Group 3, ad libitum (AL); Group 4, ad libitum + L-serine (200 mg/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 35 days 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.

Comparison and Correlation Analysis of Immune Function and Gut Microbiota of Broiler Chickens Raised in Double-Layer Cages and Litter Floor Pens

This study aimed to compare the immune function and gut microbiota between double-layer caged and litter floor pen-raised broiler chickens. Eighty meaty male chicks were selected and divided into cage group and litter floor group, with 20 replicates in each group. The broilers were raised in the same chicken house. The rearing density of the two rearing systems was same. The broilers were sampled on days 13 and 34. The results showed that compared with the cage group, the litter floor broilers had worse growth performance (23.24% increase in feed conversion ratio) in the early stage; better slaughter performance at day 42; stronger peripheral immune function (including higher lysozyme activity, T-cell ratio, Th-cell ratio, Tc-cell ratio, CD4/CD8, IL-10, B-cell ratio, IgG and IgA levels; and spleen immune-related gene expression); and stronger intestinal immune function (including higher ileum CD80, AvBD2, Mucin2, NF-κB, IL-8, IFN-γ/IL-4, and IgA mRNA expression levels and ileal mucosa sIgA levels). Compared with the cage group, the alpha diversity of ileum microbiota of the litter floor broilers was higher, and the relative abundance levels of litter breeding bacteria (Facklamia, Globicatella, and Jeotgalicoccus) and potential pathogenic bacteria (Streptococcus and Staphylococcus) were higher (P < 0.05). Through Spearman correlation analysis, it was found that enriched microbes in the ileum of litter floor broilers were positively correlated with immune function. In summary, compared with cage broilers, litter floor broilers had more potential pathogenic bacteria and litter breeding bacteria in the ileum, which may be one of the important reasons for the stronger immune function status. IMPORTANCE In China, the three-dimensional rearing system (cage) for broilers has gradually become a trend. In production, it was found that the incidence of disease in broiler chickens raised in cage systems was significantly higher than that of ground litter. Given that broilers raised on ground litter systems may be exposed to more environmental microbes, it is important to understand whether the rearing environment affects the function and status of the host immune system by altering the gut microbiota. In this study, rearing environment-derived gut microbes associated with stronger immune function in ground litter broilers were provided, which will provide new insights into strategies to target gut microbes to promote immune function and status in broilers raised in cages.

The adverse effect of heat stress and potential nutritional interventions

Heat stress can cause tissue damage and metabolic disturbances, including intestinal and liver dysfunction, acid-base imbalance, oxidative damage, inflammatory response, and immune suppression. Serious cases can lead to heatstroke, which can be life-threatening. The body often finds it challenging to counteract these adverse effects, and traditional cooling methods are limited by the inconvenience of tool portability and the difficulty of determining the cooling endpoint. Consequently, more research was conducted to prevent and mitigate the negative effect of heat stress via nutritional intervention. This article reviewed the pathological changes and altered metabolic mechanisms caused by heat stress and discussed the protein (amino acid), vitamin, trace element, and electrolyte action pathways and mechanisms to mitigate heat stress and prevent heat-related disease. The main food sources for these nutrients and the recommended micronutrient supplementation forms were summarized to provide scientific dietary protocols for special populations.

Intermittent Lighting Program Relieves the Deleterious Effect of Heat Stress on Growth, Stress Biomarkers, Physiological Status, and Immune Response of Broiler Chickens

Simple Summary

Chronic heat stress remains the most detrimental factor for broiler productivity in hot and desert regions. The manipulation of the lighting program is a useful and inexpensive tool to alleviate the negative effects of heat stress on broiler performance. The present study aimed to investigate the beneficial effects of an intermittent lighting (I.L.) program consisting of repeated periods of 1 h light to 3 h dark during a day on broiler performance under chronic heat-stress conditions. The results indicate that applying the I.L. program to heat-stressed broilers relieved the stress indicators and improved the immune response, physiological status, and growth performance of broilers. Therefore, the application of the I.L. program could be used as a beneficial strategy to recover broiler performance during heat-stress conditions.

Abstract

The effects of heat stress on broiler performance and immunological response were explored using lighting-program manipulation as a potential tool. The study included 200 Cobb500 broiler chicks that were one day old at the time of recruitment. The birds were divided into four-compartment groups with similar environments (five cages per compartment, ten chicks per cage). Starting from the fourth day of age, birds of two compartments received a continuous lighting program (23L:1D a day; C.L. groups) while birds of the other two compartments received an intermittent lighting program (1L:3D 6 times per day; I.L. groups). Within each lighting program during 22–42 d of age, one group was subjected either to a thermoneutral temperature at 24 °C or heat stress at 35 °C. The results reveal that stress biomarkers, especially the plasma concentrations of corticosterone (CORT), tumor necrosis factor-alpha (TNF-α), and malondialdehyde (MDA) were relieved by 46%, 27%, and 51%, respectively, in the I.L. treatment groups compared to the C.L. program in broiler chicks subjected to heat stress. The liver function was also improved by 24% and 32% in AST and ALT levels, respectively, in the I.L. program compared to the C.L. program in stressed birds. Furthermore, the I.L. program positively influenced the immune response of the heat-stressed broilers. Eventually, the I.L. program increased the heat-stressed broilers’ body weight gain and feed conversion ratio. It can be concluded that applying the I.L. program to broiler chickens can effectively improve their physiological balance and growth performance under heat-stress conditions.

Effect of Organic Selenium-Enriched Yeast on Relieving the Deterioration of Layer Performance, Immune Function, and Physiological Indicators Induced by Heat Stress

Heat stress (HS) induces deleterious effects on the performance of laying hens and causes economic losses for poultry industry. This study was carried out to investigate the organic effect of selenium-enriched yeast (SY) on relieving the performance, immunity and physiological deterioration induced by heat stress in laying hens. A total of 324, 28-week-old, Hy-Line Brown commercial chicken layers were randomly distributed into 4 treatments according to a 2 × 2 factorial design, with 9 hens × 9 replicates per treatment (n = 81). From 30 to 34 weeks of age, layers were exposed to 2 temperature treatments (the HS treatment groups): a thermoneutral temperature at 24°C and a heat stress at 35°C. Layers were further assigned into the 2 subgroups according to dietary supplementation with organic selenium-enriched yeast (the SY treatment groups) at either 0 or 0.4 mg/kg diet. Results indicated that all the aspects of the layer performance during the experimental period were impaired by exposure to HS, while SY supplementation improved the layer performance in both the HS and non-HS layers. Intestinal villi disruptions and liver necrotic hepatocytes were observed in the layers exposed to HS, while villi integrity and hepatocytic normality were enhanced by SY treatment. A significant (P < 0.05) decrease in the total leukocyte count, sheep red blood cell (SRBC) antibody titer, and T- and B-lymphocyte proliferation along with an increase in the heterophils/lymphocytes (H/L) ratio were observed in the HS layers compared to non-HS layers. On the contrary, SY treatment significantly (P < 0.05) improved the immune function traits in both the HS layers and non-HS layers. Furthermore, the SY treatment plays an important role in mitigating the oxidative stress and inflammation induced by HS, displaying lower levels of plasma corticosterone, lipid peroxidation, interleukin-1β, and tumor necrosis factor-α in HS layers supplemented with SY compared to HS layers without SY supplementation. These results conclude that addition of SY to the diet of laying hens could be applied as a potential nutritional approach to relieve the deterioration effects of heat stress on the immunity, physiological status, and productive performance of laying hens.

The Effect of Housing System and Gender on Relative Brain Weight, Body Temperature, Hematological Traits, and Bone Quality in Muscovy Ducks

The study was conducted during the summer season (June–August 2020). Two hundred sixty-four 5-week-old sexed Muscovy ducklings were randomly divided into four equal experimental groups by housing system and by gender. Each group had three replicates (22 birds/replicate) in a randomized design experiment. Regarding the hematological traits, the volume of leukocytes was higher in the D group (by 0.34 × 109/L; p < 0.05) than in the S group. Furthermore, body temperature was found to be higher in ducks (by 0.84 °C; p < 0.05) and in the D group (by 0.5 °C; p < 0.05) in comparison with drakes and birds from the S group. Considering relative brain weight, drakes had higher values than ducks (by 0.56 g; p < 0.05), and birds from the S group also manifested higher values (by 0.78 g; p < 0.05). In terms of bone quality, there were no differences in studied parameters of tibia and femur bones regarding housing systems. The results provide valuable evidence of differences in the fattening of intensively bred Muscovy ducks within the housing system but also regarding gender.

Effects of Spirulina (Arthrospira platensis) as a drinking water supplement during cyclical chronic heat stress on broiler chickens: Assessing algal composition, production, stress, health and immune-biochemical indices

Spirulina, the blue green algae is considered to exhibit multifaceted benefits on both human health and animal production. Three hundred sixty day old unsexed broiler chicks of CARIBROVISHAL strain were assigned to five treatment groups each comprising nine replicates of 8 chicks. The experiment was carried out during the hot humid summer season (Mid-April to May) under deep litter rearing system with uniform managemental conditions. Birds were administered orally with Spirulina through drinking water in the morning (06:00-12:00 PM) on daily basis throughout the experimental period at 5, 10, 15 and 20 gL^-1 concentration. Spirulina supplementation neither improved nor compromised production performance of broilers reared during hot climatic condition. Results based on one way analysis of variance indicated a significant effect on haemoglobin and total red blood cell count. Serum lipid content and transaminases were reduced, while serum protein concentration was higher (P < 0.01) in the groups administered with 15 and 20 gL^-1 of Spirulina. The extent of imparting shank pigmentation was improved in all the supplemented groups. Cell mediated and humoral immunity against Phytoheamagglutunin-P and Newcastle disease vaccination respectively were maximized (P < 0.05) at 20 gL^-1. These findings provide direct evidence of dose-related modulation of production, physiological and immunological attributes by Spirulina engendering its further investigation as a potential source of drinking water supplement for stress alleviation in broilers. From the results, it may concluded that Spirulina can be incorporated at 15 or 20 gL^-1 for achieving optimal improvement of health and welfare attributes in broilers reared during hot summer without compromising production.

Citrullus colocynthis Seeds: A Potential Natural Immune Modulator Source for Broiler Reared under Chronic Heat Stress

Simple Summary

Chronic heat-stress exposure directly affects broiler immune response. Immunosuppression was demonstrated in broiler exposed to chronic heat stress with deterioration in humoral and cell-mediated immune responses. Natural immune modulator material is considered as a safe material for human consumption of poultry products. Citrullus colocynthis (CC) is a natural herb plant that has traditionally been used in folk remediation. Anti-diabetic, antioxidant, and anti-inflammatory attributes are some of the CC medical properties. The present study aims to investigate the immune modulator potentials of CC seeds supplementation to chronically heat- stressed-exposed broilers. Results demonstrated that CC seeds supplementation to heat-stressed broilers was able to alleviate the negative impacts of heat stress on broiler immune responses and antioxidant status. Thus, CC seeds are suggested to be added to broilers reared under heat stress in order to improve the immune response and consequently ameliorate productivity.

Abstract

There is an extensive search for natural products that can be introduced to broiler rations to improve performance, especially during the unfavorable breeding conditions. Under heat-stress conditions, the immune response seriously deteriorates, which consequently impairs broiler production performance. Thus, the present study aimed to investigate the potentials of Citrullus colocynthis seeds (CCs) supplementation to modulate the immune response of broilers subjected to chronic heat stress. A total of 300 Cobb-500 male broiler chickens aged 21 days were randomly divided into two equal groups and reared under either thermo-neutral condition (24 ± 1 °C) or subjected to cyclic heat stress (34 ± 1 °C for 8 h). Each group was further divided into two groups (5 replicate × 15 chicks) and was fed either the basal diet or the basal diet with 0.1% CCs supplementation. The results showed that heat stress impaired the production performance by lowering the final body weight and feed intake as well as impairing feed conversion. The levels of stress markers (i.e., malondialdehyde, tumor necrosis factor-α and corticosterone) increased (p < 0.05), whereas the activity of antioxidant enzymes decreased in broilers exposed to heat stress. Further, heat stress caused direct suppression of broiler humoral and cell-mediated immune responses. The stimulating index of T and B lymphocytes proliferation, as well as the antibody titer against sheep red blood cells, were significantly (p < 0.05) reduced by heat-stress exposure. However, CCs supplementation to broilers subjected to heat stress improved (p < 0.05) the final body weight, feed intake, and feed conversion ratio (FCR), compared to the non-supplemented stressed group. The cellular and cell-mediated immune response indicators significantly enhanced (p < 0.05) with CCs supplementation. Supplementation of CCs to broilers reared under similar environmental conditions elevated the total white blood cells (TWBCs) count and the broiler stimulating index of T and B lymphocytes. It can be concluded that CC seeds can be effectively used to stimulate the immune response and improve the production performance of broilers reared under heat-stress condition.

Nutritional manipulation to combat heat stress in poultry - A comprehensive review

Global warming and climate change adversely affect livestock and poultry production sectors under tropical and subtropical conditions. Heat stress is amongst the most significant stressors influencing poultry productivity in hot climate regions, causing substantial economic losses in poultry industry. These economic losses are speculated to increase in the coming years with the rise of global temperature. Moreover, modern poultry strains are more susceptible to high ambient temperature. Heat stress has negative effects on physiological response, growth performance and laying performance, which appeared in the form of reducing feed consumption, body weight gain, egg production, feed efficiency, meat quality, egg quality and immune response. Numerous practical procedures were used to ameliorate the negative impacts of increased temperature; among them the dietary manipulation, which gains a great concern in different regions around the world. These nutritional manipulations are feed additives (natural antioxidants, minerals, electrolytes, phytobiotics, probiotics, fat, and protein), feed restriction, feed form, drinking cold water and others. However, in the large scale of poultry industry, only a few of these strategies are commonly used. The current review article deliberates the different practical applications of useful nutritional manipulations to mitigate the heat load in poultry. The documented information will be useful to poultry producers to improve the general health status and productivity of heat-stressed birds via enhancing stress tolerance, oxidative status and immune response, and thereby provide recommendations to minimize production losses due to heat stress in particular under the growing global warming crisis.

Screening and validation of candidate genes involved in the regulation of egg yolk deposition in chicken

Eggs with the same total weight may have considerable differences in yolk weight. Eggs with a high percentage of yolk have a higher nutritional value, more flavor, and are more desirable to consumers. However, a large yolk proportion means more dry matter in the eggs, which reduces the feed efficiency. The elucidation of the genetic factors of yolk quantity in eggs is of scientific and practical significance. Through RNA sequencing, we explored the transcriptome of ovarian tissue from 12 Wenchang chickens, including 6 chickens that laid eggs with a high yolk percentage (32%) and 6 that laid low yolk percentage eggs (25%). We identified a total of 362 differentially expressed genes (P-value < 0.01, log₂ fold change < −1, log₂ fold change > 1), of which 220 were upregulated and 142 were downregulated in high yolk percentage hens. According to the Gene Ontology terms annotation and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, the differentially expressed genes were associated with the regulation of various cell functions, cell differentiation and development, neuroactive ligand–receptor interactions, and calcium and ubiquitin-mediated proteolysis signaling pathways. To further filter for genes that were directly involved in yolk accumulation, the chicken quantitative trait loci database, genes within 100 kb upstream and downstream of the yolk weight trait SNP, and intersection genes in protein–protein interaction network diagrams were used to detect genes that overlapped with the differentially expressed genes. We found 7 candidate genes in total, MNR2, AOX1, ANTXRL, GRAMD1C, EEF2, COMP, and JUND, which affect female reproductive performance and the growth and development of follicles, supporting cell transport, cell proliferation, and differentiation. All candidate genes and several randomly selected genes were verified by quantitative real time PCR, and the results were consistent with the RNA sequencing. In conclusion, investigating the molecular mechanisms of high yolk percentage traits will allow breeding strategies to be optimized to alter the percentage of yolk in chicken eggs.

Perspectives on biometeorological research on the African continent

Since the first issue of the International Journal of Biometeorology in 1957, a total of 135 papers have reported on research in or of African countries. The majority of these have been on topics of animal biometeorology (36%), and the greatest proportion (24%) are situated in Nigeria. There has been a considerable increase in papers on African biometeorology since 2011, with those from this past decade accounting for 58% of all African papers in the journal. This occurs concurrent to an increase in the total number of papers published in the journal, driven by a move to the Editorial Manager system. While 66% of the papers on African biometeorology in the journal are authored by at least one person with an affiliation in the African continent, only 15 African countries are represented in the total authorship. As much of the African continent is projected to experience climatic changes exceeding the global mean, as much of the region is involved in animal and plant farming, and as seasonally-fluctuating and climatically affected diseases are common place, this low representation of work in Africa is surprising. This points to the need for greater awareness among African researchers of the discipline of biometeorology, greater involvement of African biometeorologists in International Society of Biometeorology and Commission meetings, and the inclusion of a greater number of African academics in the review process. This would be beneficial to the Society in increasing diversity and encouraging a more cosmopolitan engagement, and to the recognition of scientific development in African countries.

Changes in facial surface temperature of laying hens under different thermal conditions

OBJECTIVE

The purpose of this study was to identify through infrared thermal imaging technology the facial surface temperature (FST) of laying hens in response to the variations in their thermal environment, and to identify the regional differences in FST to determine the most stable and reliable facial regions for monitoring of thermoregulatory status in chickens.

METHODS

Thirty Hy-Line Brown hens (25-week-old) were sequentially exposed to three different thermal conditions; optimal (OT, 22°C±2°C), low (LT, 10°C±4°C), and high temperature (HT, 30°C±2°C). The mean values of FST in five facial regions including around the eyes, earlobes, wattles, beak and nose, and comb were recorded through infrared thermography. The maximum FST (MFST) was also identified among the five face-selective regions, and its relationship with temperature-humidity index (THI) was established to identify the range of MFST in response to the variations in their thermal environment.

RESULTS

Hens exposed to OT condition at 15:00 displayed a higher temperature at wattles and around the eyes compared to other regions (p<0.001). However, under LT condition at 05:00 to 08:00, around the eyes surface temperature showed the highest value (p<0.01). In HT, wattles temperature tended to show the highest temperature over almost time intervals. Main distribution regions of MFST were wattles (63.3%) and around the eyes (16.7%) in OT, around the eyes (50%) in LT, and wattles (62.2%) and comb (18.3%) in HT. The regression equation between MFST and THI was estimated as MFST = 35.37+ 0.2383×THI (R2 = 0.44; p<0.001).

CONCLUSION

The FST and the frequency of MFST in each facial region of laying hens responded sensitively to the variations in the thermal environment. The findings of this experiment provide useful information about the effect of the thermal conditions on the specific facial regions, thus offering an opportunity to stress and welfare assessment in poultry research and industry.

Correlation analysis of muscle amino acid deposition and gut microbiota profile of broilers reared at different ambient temperatures

Objective

Temperature could influence protein and amino acid deposition as well as gut microbiota profile and composition. However, the specific effects of ambient temperature on amino acids deposition and gut microbiota composition remain insufficiently understood.

Methods

A total of 300 one-day-old Avian broilers were randomly divided into three groups and reared at high, medium, and low temperature (HT, MT, and LT), respectively. Breast muscle and fecal samples were collected for amino acid composition analysis and 16S rRNA gene sequence analysis.

Results

Our data showed that compared to the MT group, there was a decrease of muscle leucine and tyrosine (p<0.05), as well as an increase of methionine in the HT group (p<0.05) and a decrease of serine in the LT group. Examination of microbiota shift revealed that at genus level, the relative abundance of Turicibacter and Parabacteroides was increased in the HT group (p<0.05) and that the relative abundances of Pandoraea, Achromobacter, Prevotella, Brevundimonas, and Stenotrophomonas in the LT group were higher than those in the MT group (p<0.05). In addition, there were substantial correlations between microbes and amino acids. In the HT group. Turicibacter was negatively correlated with aspartic acid and tyrosine, whereas Parabacteroides was positively correlated with methionine (p<0.05). In the LT group, there were multiple positive correlations between Achromobacter and arginine, isoleucine or tyrosine; between Prevotella and cysteine or phenylalanine; between Brevundimonas and cysteine; and between Stenotrophomonas and cysteine as well as a negative correlation between Stenotrophomonas and serine.

Conclusion

Our findings demonstrated that amino acid content of breast muscle and intestinal microbiota profile was affected by different ambient temperatures. Under heat exposure, augmented abundance of Parabacteroides was correlated with elevated methionine. Low temperature treatment may affect muscle tyrosine content through the regulation of Achromobacter.

Identification of genes related to effects of stress on immune function in the spleen in a chicken stress model using transcriptome analysis

Stress is a physiological manifestation of the body's defense against adverse effects of external environment, but the molecular regulatory mechanism of stress effects on immune function of poultry has not been fully clarified. In this study, 7-day-old Chinese local breed Gushi cocks were used as model animal, and the stress model was successfully constructed by adding corticosterone (CORT) 30 mg/kg basic diet for 7 days. The spleen transcriptomes of the control group (B_S group) and the stress model group (C_S group) was determined by high-throughput mRNA sequencing (RNA-Seq) technology, and a total of 269 significantly differentially expressed genes (SDEGs) were obtained (Padj < 0.05, |FC| ≥ 2 and FPKM > 1). Compared with B_S group, there were 140 significantly up-regulated genes and 129 significantly down-regulated genes in C_S group. The immune/stress-related Gene Ontology (GO) terms included positive regulation of T cell mediated immunity, chemokine-mediated signaling pathway, T cell mediated immunity and so on. The SDEGs such as IL8L1, HSPA8, HSPA2, RSAD2, CCR8L and DMB1 were involved in these GO terms. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that the SDEGs participated in many immune-related signaling pathways. The immune-related genes HSPA2, HSPA8, HSP90AA1, HSPH1 and HERPUD1 were enriched in Protein processing in endoplasmic reticulum pathway, IL8L1, CXCL13L2, CCR6, LEPR, CCR9 and CCR8L were enriched in Cytokine-cytokine receptor interaction pathway. The protein-protein interactions (PPI) analysis showed HSPA8, HSPA2 and IL8L1 as key core nodes had 7 interactions and may play important roles in the regulation of CORT-induced stress effects on immune function. The data onto this study enriched the genomic study of stress effects on immune function, and provided unique insights into the molecular mechanism of stress effects on immune function, and the genes identified in this study can be candidates for future research on stress response.

The Clinical Application of a Self-developed Gasless Laparoendoscopic Operation Field Formation Device on Patients Undergoing Cholecystectomy

BACKGROUND

We have designed a new gasless laparoscopic operation field formation (LOFF) device for cholecystectomy which was successfully tested on animal model. The goal of this study is to investigate the feasibility, safety and effectiveness of this LOFF device on patients undergoing cholecystectomy.

METHODS

Patients with cholecystolithiasis or gallbladder polyps who underwent single port cholecystectomy from June 2015 to May 2016 were retrospectively reviewed. Either the LOFF-assisted laparoendoscopic single-port surgery (LESS) (LOFF-LESS) or the traditional LESS was performed. Operation time, intraoperative bleeding, postoperative hospital stay, surgical complications, incision pain score, shoulder and back pain and cosmetic satisfaction were compared.

RESULTS

A total of 186 patients were included in this study, with 79 in the LOFF-LESS group and 107 in the LESS group. There was no significant difference between LOFF-LESS group and LESS group in operation field establishment time, cholecystectomy time, intraoperative bleeding, postoperative hospital stay, incision pain and cosmetic satisfaction. A lower intraoperative arterial carbon dioxide pressure was documented in the LOFF-LESS group (P<0.01). The incidence of postoperative shoulder and back pain was significantly lower in LOFF-LESS group (P<0.01).

CONCLUSION

LOFF-LESS has comparable benefits of traditional LESS; it deceases incidence of pneumoperitoneum related complications as well.

Relationship between heat stress exposure and some immunological parameters among foundry workers

Occupational exposure to heat stress may lead to changes in blood cell count. The objective of this retrospective descriptive-analytical field study is to investigate the relationship between heat stress exposure and some immunological parameters among foundry workers. This study was carried out on 55 subjects of which, 35 were working in a foundry unit (exposed group) and 20 were working in a computer numerical control (CNC) machining unit (control group). The measurement method consisted of taking 10 cc of the subjects' blood between 10 am and 2 pm and then performing the automated blood cell counting and enzyme-linked immunosorbent assay (ELISA) on the sample. Environmental parameters such as noise levels, lighting, and the wet-bulb globe temperature (WBGT) index were measured at the subjects' workstations. All measurements were made in the first half of the month of July. The mean WBGT index was 22.5 ± 2.16 °C for the control group and 32.97 ± 3.22 °C for the exposed group. The laboratory test results show a significant decrease in white blood cell count and lymphocyte levels and a significant increase in neutrophil levels and neutrophil to lymphocyte ratio in exposed group compared with control ones (P < 0.05). IgM levels decrease under heat stress, but we do not observe significant differences between IgG and IgA levels between two groups. A significant negative correlation was observed between white blood cell count, lymphocyte levels, and IgM concentration with WBGT index and significant positive correlation was observed between neutrophil and neutrophil to lymphocyte ratio with WBGT index. No significant correlation was observed between sound pressure levels and light intensity with studied immunological parameters. In conclusion, under heat stress conditions, leukocytes levels and immunoglobulin concentration may reduce and it may weaken and suppress the human immune system.

High-temperature exposure alters the community structure and functional features of the intestinal microbiota in Shaoxing ducks (Anas platyrhynchos)

The gut microbiome is a complex ecosystem that contributes to host nutrition and health. However, our current knowledge of the relationship between ambient temperature and gut microbiota of poultry is still limited. The objective of the present study was to characterize the intestinal microbiota of ducks exposed to high ambient temperature. Sixty 60-day-old Shaoxing ducks were allocated to control and heat-treated groups. The ducks in the control group were kept at 25°C, and the ducks in the heat treatment group were raised at 30–40°C, which simulated the temperature change of day and night in summer. After 15 D, the intestinal contents of the duodenum, jejunum, and ileum were obtained from 6 ducks of each group. Genomic DNA was extracted and amplified based on the V4–V5 hypervariable region of 16S rRNA. The results showed that Firmicutes was the dominant bacterial phylum with the highest abundance in the contents of the small intestine of ducks, and the relative abundance of the phylum Firmicutes in all 3 intestinal segments was increased by high temperature. At the genus level, Lactobacillus was found to be the most dominant bacterial genus across 3 gut segments, and its abundance was increased in ducks under heat treatment. Compared with the corresponding intestine segment of control ducks, a total of 36 genera in the duodenum, 19 genera in the jejunum, and 6 genera in the ileum of heat-treated ducks were found to be significantly different in the abundance (linear discriminant analysis score >3.0, P < 0.05). Functional prediction of gut microbiota revealed that high temperature caused changes in the abundance of metabolism and transcription-related pathways. It is noteworthy that most of the altered pathways are related to metabolism. In conclusion, high temperature induced remarkable taxonomic changes in the gut microbiome of ducks, which might be related to the negative effects of high temperature in ducks. Our present study provided an important theoretical ground for high-temperature intervention.

Efeito da manipulação térmica durante a incubação sobre as variáveis hematológicas, bioquímica sérica e morfometria da bolsa cloacal de codornas japonesas submetidas ao estresse crônico por calor

RESUMO Objetivou-se avaliar os efeitos da manipulação da temperatura de incubação sobre a resposta imune de codornas desafiadas termicamente após eclosão. Para isso, foram utilizados 540 ovos, distribuídos em três incubadoras, com temperatura de 37,8°C e umidade de 60%. A partir do sexto dia de incubação até a eclosão, as temperaturas foram ajustadas em 37,8°C (padrão), 38,5°C (intermediária) e 39,5°C (alta). Após a eclosão as codornas foram pesadas e distribuídas, em delineamento inteiramente ao acaso, com três temperaturas de incubação (37,8, 38,5 e 39,5°C) e duas temperaturas de ambiente (estresse e termoneutro). Aos 10, 20, 30 e 40 dias, quatro codornas por tratamento foram eutanasiadas para coleta da bolsa cloacal, do fígado e do coração, para se determinar o peso absoluto (g), o peso relativo (%) e a área dos folículos bursais. Sangue foi coletado para realização do hemograma, do leucograma e da bioquímica sérica. Os dados foram analisados e as diferenças entre as médias foram determinadas pelo teste de Tukey a 5%. O estresse térmico por calor, a partir dos 20 dias, promove redução no peso absoluto do fígado, do coração, da bolsa cloacal e na área dos folículos bursais, além de heterofilia, linfopenia e aumento da relação heterófilo/linfócito. Em conclusão, o estresse térmico por calor após 10 dias de idade pode causar imunossupressão.

Floods, Hurricanes, and Other Catastrophes: A Challenge for the Immune System of Livestock and Other Animals

Climate change involves different dramatic phenomena including desertification and wildfires, severe storms such as hurricanes and blizzards, increased sea levels resulting in flooding coastal cities and rise of atmospheric CO₂ concentration. The alteration of the climate in a specific region affects the life of indigenous animals and humans. The climate changes influence living beings both directly and indirectly. The immune system of animals dramatically suffers the climate instability, making animals more susceptible to infectious and not infectious diseases. Different species of livestock animals respond with similar mechanisms to global warming, but some of them are more susceptible depending on their age, metabolism, and genetic conditions. The selection and study of autochthonous species and breeds, more easily adapted to specific environmental conditions could be an interesting strategy to face livestock rearing in the future.

Genetic lines respond uniquely within the chicken thymic transcriptome to acute heat stress and low dose lipopolysaccharide

Exposure to high temperatures is known to impair immune functions and disease resistance of poultry. Characterizing changes in the transcriptome can help identify mechanisms by which immune tissues, such as the thymus, respond to heat stress. In this study, 22-day-old chickens from two genetic lines (a relatively resistant Fayoumi line and a more susceptible broiler line) were exposed to acute heat stress (35 °C) and/or immune simulation with lipopolysaccharide (LPS; 100 µg/kg). Transcriptome responses in the thymus were identified by RNA-sequencing (RNA-seq). Expression of most genes was unaffected by heat and/or LPS in the Fayoumi line, whereas these treatments had more impact in the broiler line. Comparisons between the broiler and Fayoumi transcriptomes identified a large number of significant genes both at homeostasis and in response to treatment. Functional analyses predicted that gene expression changes impact immune responses, apoptosis, cell activation, migration, and adhesion. In broilers, acute heat stress changed thymic expression responses to LPS and could impact thymocyte survival and trafficking, and thereby contribute to the negative effects of high temperatures on immune responses. Identification of these genes and pathways provides a foundation for testing targets to improve disease resistance in heat-stressed chickens.

Identification of Serum Biomarkers for Intestinal Integrity in a Broiler Chicken Malabsorption Model

Intestinal health is essential for feed efficiency and growth in animal agriculture and is dependent on barrier function, inflammation and dysbiosis. Our laboratory has published a nutritional model to induce gut inflammation using rye as a source of energy in poultry. More recently, we have used this model as an assessment of a nutritional rehabilitation model for better understanding of childhood undernutrition. The objective of this brief research report was to use a well-establish malabsorption model in broiler chickens using corn and rye as an energy source to identify several intestinal health biomarkers in the serum. To screen for inflammatory biomarkers, seven commercially available tests were used including Griess, superoxide dismutase, thiobarbituric acid reactive substances, Total antioxidant capacity, extracellular-signal-regulated kinase, Citrulline, and Interferon-ɤ; total IgA from cloacal swab was also measured. In the present study, chickens fed rye had a significant (P < 0.05) reduction in body weight and body weight gain at 10 day when compared with chickens that received the corn diet. In the second phase of the experiment, chickens that remain with the corn diet had significant differences in body weight and body weight gain. No significant differences were observed for any of the four antioxidant biomarkers evaluated in the sera (P > 0.05). However, significant differences were observed in serum citrulline and IFN-ɤ, as well as in cloacal IgA, in broiler chickens fed with rye, suggesting their potential use as biomarkers to study intestinal inflammation.

Changes in morphology and miRNAs expression in small intestines of Shaoxing ducks in response to high temperature

During summer days the extreme heat may cause damage to the integrity of animal intestinal barrier. Little information is available concerning morphological changes in the duck intestines in response to high temperature. And the molecular mechanisms underlying the pathogenesis of high temperature-induced intestinal injury remain undefined. MicroRNAs (miRNAs) are known to play key roles in post-transcriptional regulation of gene expression that influences various biological processes. The purpose of this study was to explore the changes in morphology and miRNA expression profiles of the three intestinal segments (duodenum, jejunum and ileum) of ducks in response to high temperature. Sixty female Shaoxing ducks (Anas platyrhynchos), 60 days old, were allocated in two groups, including control ducks kept at 25 °C, and ducks subjected to high ambient temperatures of 30-40 °C for 15 successive days, which mimicked the diurnal temperature variations experienced in hot seasons. Three ducks from each group were executed at the end of feeding experiment, and the samples of three intestinal segments were collected for morphological examination and Illumina deep sequencing analyses. Histopathological examination of the intestinal mucous membrane was performed with HE staining method. The results demonstrated that varying degrees of damage to each intestinal segment were found in heat-treated ducks, and there were more severe injuries in duodenum and jejunum than those in ileum. Illumina high-throughput sequencing and bioinformatic methods were employed in this study to identify the miRNA expression profile of three different intestinal tissues in control and heat-treated ducks. A total of 75,981,636, 88,345,563 and 100,179,422 raw reads were obtained from duodenum, jejunum and ileum, respectively, from which 74,797,633 clean reads in duodenal libraries, 86,406,445 clean reads in jejunal libraries, and 98,518,858 lean reads in ileal libraries were derived after quality control, respectively. And a total of 276 known and 182 novel miRNAs were identified in the three intestinal segments of ducks under control and heat-treated conditions. By comparing the same tissues in different conditions, 16, 18 and 15 miRNAs were found to be significantly differentially expressed between control and heat-treated ducks in duodenum, jejunum and ileum, respectively, of which 1 miRNA was expressed in both the duodenum and jejunum, 2 miRNAs were expressed in both the duodenum and ileum, and 3 miRNAs were found to be expressed in both the jejunum and ileum. In addition, two differentially expressed miRNAs in each comparison were randomly selected and validated by quantitative qRT-PCR. Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that the differentially expressed miRNAs may be involved in the high temperature-induced intestinal injury in ducks. Our work provides the comprehensive miRNA expression profiles of small intestines in the normal and heat-treated ducks. These findings suggest the involvement of specific molecular mechanisms of post-transcriptional regulation to explain the high temperature-induced changes in the duck small intestine.

Propolis alleviates the negative effects of heat stress on egg production, egg quality, physiological and immunological aspects of laying Japanese quail

The present work was carried out to investigate the effects of dietary propolis supplementation to laying Japanese quail (Coturnix coturnix japonica) on egg production, egg quality, physiological and immunological aspects under heat stress conditions. A total of 200, 21-day-old, Japanese quail females were distributed equally into standard wired cages in two identical environmentally-controlled rooms (10 cages per room, 10 birds per cage). From 29–70 d of age, the quail birds in the first room remained at a normal temperature of 24°C (C group), whereas the quail birds in the second room were kept under heat stress at 35°C (HS group). Each group was further assigned to 2 propolis subgroups (5 cages per subgroup); one of them received a basal diet without propolis supplementation (-PR subgroup), while, the other received 1 g propolis/ kg basal diet (+PR subgroup). In the present study, performance and egg production of laying quail were significantly (P<0.001) impaired by HS treatment and improved by the PR treatment. Similarly, the negative and positive effects of HS and PR, respectively, were appeared on the egg shell thickness and yolk index. Stress indicators in laying quail were significantly (P<0.001) increased by HS, while, PR significantly (P<0.05) moderated these levels in the HS+PR group when compared to the HS-PR quail group. In addition to the positive impact of PR on the plasma levels of calcium, phosphorus, and albumin, it also normalized the plasma levels of alanine aminotransferase and cholesterol in the heat-stressed quail birds. Moreover, the quail birds in the HS groups expressed lower immunological aspects than those in the C group, while, the addition of propolis to the diets enhanced the immune status of laying quail birds under HS conditions. These results strongly suggest that dietary propolis supplementation could be a successful attempt to maintain the performance and egg production of laying Japanese quail at convenient levels under heat stress conditions.

Effect of fisetin and probiotic supplementation on erythrocyte osmotic fragility, malondialdehyde concentration and superoxide dismutase activity in broiler chickens exposed to heat stress

The aim of the study was to evaluate effects of fisetin and probiotic on erythrocyte osmotic fragility (EOF), malondialdehyde (MDA) and superoxide dismutase (SOD) in broiler chickens exposed to heat stress. Sixty day-old broilers were divided into: Group I (control) given distilled water; Group II, fisetin (5 mg/kg); Group III, probiotic Saccharomyces cerevisiae (4.125 × 106 cfu/100 ml); and Group IV, fisetin (5 mg/kg) + probiotic (4.125 × 106 cfu/100 ml) orally for 7 days. Blood samples collected from 42-day-old birds were evaluated for EOF, serum MDA concentration and SOD activity. Percentage EOF at 0.5% NaCl was lower (P<0.05) in fisetin, probiotic and fisetin + probiotic groups (34.26 ± 0.98%, 35.65 ± 0.81% and 34.25 ± 1.98%, respectively) than in controls (48.42 ± 0.40%). The MDA concentrations in broiler chickens administered with fisetin (14.37 ± 1.15 nmol/l), probiotic (5.66 ± 1.06 nmol/l) and fisetin + probiotic (4.136 ± 0.58 nmol/l) were lower (P<0.05) than in controls (22.64 ± 2.95 nmol/l). Activities of SOD were higher (P<0.05) in fisetin, probiotic and fisetin + probiotic broiler chickens (6.34 ± 0.24 IU/l, 5.67 ± 0.09 IU/l and 5.93 ± 0.13 IU/l, respectively) than in controls (5.37 ± 0.09 IU/l). Fisetin + probiotic ameliorated oxidative stress changes in broiler chickens better than fisetin or probiotic alone. In conclusion, administration of fisetin or probiotic and, especially their combination, decreased EOF, lipoperoxidation and increased superoxide dismutase activity in broiler chickens exposed to heat stress.

Propolis supplementation attenuates the negative effects of oxidative stress induced by paraquat injection on productive performance and immune function in turkey poults

Paraquat (PQ) is used as a herbicide in agriculture and causes oxidative and inflammatory damage to animal tissues. The current study was conducted to investigate the positive effects of dietary propolis (PR), as a potent naturally produced antioxidant, on growth performance and immune function of turkey poults exposed to oxidative stress induced by PQ injection. Native male turkey poults (n = 120, 49-d-old) were randomly assigned into 4 groups: poults received a basal diet with a daily subcutaneous PQ injection of 5 mg/kg BW for 7 consecutive days (PQ group), an experimental diet containing 1 g/kg PR with a daily subcutaneous PQ injection for 7 days (PR+PQ group), or received the experimental PR diet with a daily subcutaneous injection of 0.5 mL sterile saline for 7 days (PR group); while the control poults received a basal diet with a daily subcutaneous saline injection for 7 consecutive days (C group). The productive performance in the PQ group showed a significant (P < 0.05) reduction in the weight gain (WG) and feed intake (FI), and impaired feed conversion ratio (FCR). Propolis supplementation in the PR+PQ group significantly ameliorated the PQ effects on WG and FCR. Turkey poults of the PQ and PR+PQ groups had a significant augmentation in the blood malondialdehyde (MDA), tumor necrosis factor-α (TNFα), and corticosterone levels, and in contrast, a significant reduction in the triiodothyronine (T₃), when compared to the C group. While propolis significantly reduced the MDA and corticosterone, and increased the T₃ levels in the PR+PQ group compared to the PQ group. Furthermore, the dietary PR supplementation significantly limited the PQ-suppressive effects on cell- and humoral-mediated immunity and lymphocyte proliferation of turkey poults. In addition, propolis supplementation in the PR and PR+PQ groups markedly reversed the PQ-induced DNA fragmentation and heat shock protein 70 (Hsp70) over-expression in blood cells. It can be concluded that PR could improve turkey immunity and performance, particularly under inflammation and oxidative stress induced by PQ exposure.

The importance of propolis in alleviating the negative physiological effects of heat stress in quail chicks

Heat stress is one of the most detrimental confrontations in tropical and subtropical regions of the world, causing considerable economic losses in poultry production. Propolis, a resinous product of worker honeybees, possesses several biological activities that could be used to alleviate the deleterious effects of high environmental temperature on poultry production. The current study was aimed at evaluating the effects of propolis supplementation to Japanese quail (Coturnix coturnix japonica) diets on the production performance, intestinal histomorphology, relative physiological and immunological parameters, and selected gene expression under heat stress conditions. Three hundred one-day-old Japanese quail chicks were randomly distributed into 20 wired-cages. At 28 d of age, the birds were divided into 2 temperature treatment groups; a normal at 24°C (C group) and a heat stress at 35°C (HS group). The birds in each group were further assigned to 2 subgroups; one of them was fed on a basal diet without propolis supplementation (-Pr subgroup) while the other was supplemented with propolis (+Pr subgroup). Production performance including body weight gain, feed intake and feed conversion ratio were measured. The intestinal histomorphological measurements were also performed for all treatment groups. Relative physiological parameters including body temperature, corticosterone hormone level, malondialdehyde (MDA) and free triiodothyronine hormone (fT3), as well as the relative immunological parameters including the total white blood cells count (TWBC’s), heterophil/lymphocyte (H/L) ratio and lymphocyte proliferation index, were also measured. Furthermore, the mRNA expression for toll like receptor 5 (TLR5), cysteine-aspartic protease-6 (CASP6) and heat shock proteins 70 and 90 (Hsp70 and Hsp90) genes was quantified in this study. The quail production performance was significantly (P<0.05) impaired by HS treatment, while Pr treatment significantly improved the quail production performance. The villus width and area were significantly (P<0.05) lower in the HS compared to the C group, while Pr treatment significantly increased crypts depth of quail. A negative impact of HS treatment was observed on the physiological status of quail; however, propolis significantly alleviated this negative effect. Moreover, quail of the HS group expressed lower immunological parameters than C group, while propolis enhanced the immune status of the quail. The relative mRNA expression of TLR5 gene was down-regulated by HS treatment while it was up-regulated by the Pr treatment. Furthermore, the positive effects of propolis in HS-quail were evidenced by normalizing the high expressions of CASP6 and Hsp70 genes when compared to the C group. Based on these results, the addition of propolis to quail diets as a potential nutritional strategy in order to improve their performance, especially under heat stress conditions, is recommended.