Hepatic heat shock proteins, antioxidant-related genes, and immunocompetence of heat-stressed broilers in response to short periods of incubation during egg storage and thermal conditioning

The potential of pomegranate peel supplementation in Yellow-feathered broilers: effects on growth performance, serum biochemistry, antioxidant capacity, intestinal health, intestinal microbiota, and duodenal mucosal metabolites

This study aimed to investigate the effects of dietary supplementation with pomegranate peel powder (PP) on the growth performance, serum biochemistry, antioxidant capacity, intestinal microbiota, and duodenal mucosal metabolites of yellow-feathered broilers. A total of 360 yellow-feathered broilers were randomly divided into three groups, with their diets supplemented with different levels of PP (0, 1, and 4 g/kg) for 42 days. Dietary supplementation with PP significantly increased the average body weight and average daily gain of yellow-feathered broilers during the periods of 1-21 and 22-42 days, while reducing the feed conversion ratio (p < 0.05). It also decreased the serum levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and uric acid, increased the activities of glutathione peroxidase and superoxide dismutase, and reduced malondialdehyde content in the serum, liver, and intestinal mucosa (p < 0.05). Furthermore, PP supplementation promoted the mRNA expression of farnesoid X receptor, peroxisome proliferator-activated receptor alpha, fatty acid-binding protein 4, epidermal growth factor/epidermal growth factor receptor, and B-cell lymphoma 2, while decreasing the mRNA expression of caspase-1 and interleukin-1 beta (p < 0.05). Regarding mucosal metabolites, PP supplementation increased the contents of polyunsaturated fatty acids (cis-11-eicosenoic acid, cis-13,16-docosadienoic acid, and cis-11,14-eicosadienoic acid), prostaglandin E2/G2, and secondary bile acids (apocholic, hyodeoxycholic, 7-ketodeoxycholic, and omega-muricholic acids) in the mucosa (p < 0.05). In terms of cecal microbiota, PP supplementation increased the β-diversity index (p < 0.05), elevated the relative abundances of Bacteroidota, Alistipes, Bacilli, and Actinobacteriota, and reduced the relative abundances of Clostridia and Gammaproteobacteria (p < 0.05). In conclusion, dietary supplementation of PP can improve intestinal health and growth performance of yellow-feathered broilers by regulating the composition of the gut microbiota.

The impact of in ovo injection of cluster bean peptide on hatchability, growth performance, carcass characteristics, digestive enzymes, and blood indices of broiler chickens

The administration of bioactive short peptides through in ovo feeding can improve the overall health and performance of broiler chickens for the poultry industry. Additionally, bioactive peptides possess biological features that have the potential to be beneficial in preventing many metabolic illnesses; hence, the ingestion of these peptides holds the potential to be advantageous for human health. In light of this, the current work aimed to study the impacts of in ovo feeding during the late stages of embryonic development with cluster bean peptide (CBP) on the hatchability, productive performance, lipid profile, liver and kidney functions, immunological response, and antioxidant status of broilers. Six hundred and forty-eight (648) fertilized Ross 308 broiler breeder eggs were used in this study. To remove infertile eggs and dead embryos, the eggs were manually candled on 7 and 17 day of incubation (DOI). On the 18.5th DOI, the eggs were separated into four treatment groups (156 eggs/each), and the first group did not receive any treatment and represented the negative control (NC). Meanwhile, the other treatment groups were injected into the amnion membrane. The second group was only subjected to needle penetration and represented the positive control (PC). The third group was denoted by the letter T1 and received an injection of 1 mg CBP/egg. The fourth group was denoted by the letter T2 and received an injection of 2 mg CBP/egg. In ovo feeding by CBP exhibited significant improvements in the body weight of newly hatched chicks, particularly at the 2 mg CBP level. The administration with CBP did not significantly affect the carcass characteristics of 28-day-old broilers. In ovo-administrated groups with CBP, higher plasma concentrations of total protein and its fractions were observed at hatch and on day 28 of age. In ovo treatment with CBP, blood lipid profile parameters significantly improved at hatch and 28 days of age. Liver and kidney function parameters were improved in response to the in ovo administration with CBP in newly hatched chicks and on day 28 of age. Blood levels of glutathione (GSH) and superoxide dismutase (SOD) were considerably higher in the in ovo-administered groups with CBP; while levels of malondialdehyde (MDA) were significantly reduced due to CBP administration. The activity of digestive enzymes in blood plasma was decreased in newly hatched chicks but increased in 28-day-old broilers in response to in ovo administration with CBP. There was an improvement in the immunological response of hatched chicks from groups injected with CBP, particularly the T2 group (2 mg CBP), as evidenced by increased IgM and IgG levels. The findings presented here indicate that the in ovo administration with CBP, specifically at a dosage of 2 mg, improved growth performance and immune and antioxidant functions.

Dietary Dunaliella salina microalgae enriches eggs with carotenoids and long-chain omega-3 fatty acids, enhancing the antioxidant and immune responses in heat-stressed laying hens

Introduction

Dunaliella salina (DS) is a prospective source of bioactive carotenoids, including beta-carotene, zeaxanthin, and omega-3 fatty acids. The effect of dietary supplementation of DS on the productive performance, immune response, and egg quality of heat-stressed laying hens has not been comprehensively studied. We investigated how dietary D. salina supplementation affects the deposition of bioactive carotenoids and omega-3 fatty acids in egg yolks of laying hens experiencing summer heat stress, as determined by the Temperature-Humidity Index (THI). The influence of D. salina supplementation on the productive performance, immune response, and antioxidant status of heat-stressed laying hens was assessed.

Methods

A total of 120 Elma-Brown laying hens were assigned to four dietary treatments with DS supplementation at 0 (control), 0.5, 1, and 1.5 g/kg of diet. The experiment lasted 60 days, during which eggs were collected at three time points: 15, 30, and 60 days from the start of the study.

Results and discussion

including DS at 1 g/kg improved egg production and feed conversion, with improved antioxidant status via a marked inhibitory effect on malondialdehyde in heat-stressed laying hens. Dietary 0.5 g/kg DS improved the immune response of heat-stressed laying hens compared to that of the control group. The highest dose of DS (1.5 g/kg diet) increased astaxanthin, zeaxanthin, lutein, and total carotenoids by 9.8%, 50.44%, 49.19%, and 84.21% (p < 0.05), respectively, and decreased β-carotene by 38.61% (p < 0.05), when compared with the control. Feeding DS to heat-stressed laying hens increased the concentrations of the long-chain Omega-3 (docosahexaenoic acid) in egg yolks; the dose of 0.5 g/kg diet for 15 d produced an increase in the DHA content by104.76% above the control group (p < 0.5). Feeding DS improved the nutritional indices of egg yolks, as egg yolks retained a high ratio of monounsaturated fatty acids (MUFA)/polyunsaturated fatty acids (PUFA)/saturated fatty acids, low thrombogenicity index (IT), low atherogenicity index (IA), and high hypocholesterolemic/hypercholesterolemic index (h/H). Feeding heat-stressed laying hens DS improved their productivity and antioxidant status, resulting in functional eggs enriched with bioactive carotenoids (astaxanthin, zeaxanthin, and lutein) and beneficial omega-3 fatty acids.

The potential of supplementing compound organic trace elements at lower levels in Chinese yellow- feathered broiler diets, part II: Impacts on growth performance, gut health, intestinal microbiota, and fecal mineral excretion

This study aimed to investigate the effects of reducing inorganic trace minerals (ITM) by supplementing compound organic trace minerals (OTM) chelates on growth performance, fecal mineral excretion, intestinal health, and cecal microbiota of yellow-feathered broilers. A total of 960 one day old male broilers were randomly assigned to 6 treatments, among which birds were fed with the basal diets (negative control, NC), or supplemented with 1,000 mg/kg (positive control, PC), 300, and 500 mg/kg ITM or OTM, respectively. Dietary supplementation of OTM significantly increased the average daily gain (ADG) during 22-53 d and 1-53 d, and reduced the fecal emissions of Fe, Cu, Zn, and Mn of Chinese yellow-feathered broilers (P < 0.05). Furthermore, the OTM300 group significantly reduced the crypt depth in the duodenum, and increased the ratio of villus height to crypt depth (V/C) in the duodenum and jejunum (P < 0.05). The mRNA expression of TGF-β, Bcl-2, CAT, and GPX4 as well as tight junction proteins (occludin, ZO-1, claudin-1, and claudin-5) in jejunum mucosa were significantly increased by compound OTM when comparing with ITM300 group (P < 0.05). Moreover, dietary compound OTM significantly changed the Chao1 index and β diversity index of cecal microbiota of Chinese yellow-feathered broilers. The abundances of Firmicutes (phylum), Eubacterium_coprostanoligenes_group (family) and Oscillibacter (genus) were increased, while the abundances of Bacteroidetes (phylum) and Rikenellaceae RC9 group (genus) were decreased by OTM treatment. Spearman correlation analysis showed that the mRNA of occludin and jejunal V/C ratio were positively correlated with the abundance of Firmicutes (phylum), but negatively correlated with the abundance of Bacteroidota (phylum). In addition, the abundance of Eubacterium_coprostanoligenes_group (family) was positively correlated with the mRNA of claudin-1, Bcl-2, and TGF-β. PICRUST prediction of microbial function revealed that OTM treatment enriched the pathways related to amino acid metabolism and DNA replication. In conclusion, dietary supplementation at lower levels of compound OTM to replace ITM could improve growth performance and intestinal health, and reduce the fecal excretion of trace elements by modulation of cecal microbiota community and diversity in Chinese yellow-feathered broilers.

Effects of microencapsulated essential oils and seaweed meal on growth performance, digestive enzymes, intestinal morphology, liver functions, and plasma biomarkers in broiler chickens

Globally, poultry production has increased to meet the demand for animal protein. Traditionally, antibiotic growth promoters have been used to enhance growth performance and prevent infections in commercial poultry practices. However, concerns regarding antimicrobial resistance have triggered interest in alternative solutions, such as essential oils (EOs) and seaweed additives. The aim of the current study was to assess the impact of a microencapsulated blend of EOs (cinnamaldehyde, eugenol, and thymol) and Ascophyllum nodosum seaweed meal on growth performance, intestinal function, blood biomarkers, and hepatic gene expression in broiler chickens. A total of 440 Arbor Acres chicks were randomly assigned to either a control (CON) or treatment (NEX) group. Each treatment was divided into 11 replicates (20 birds per replicate). NEX chicks were supplemented with 100 mg/kg feed containing a microencapsulated blend of EOs (cinnamaldehyde, eugenol, and thymol) and Ascophyllum nodosum seaweed meal. Data were analyzed using the UNIVARIATE procedure in SAS software. Each replicate was considered an experimental unit. Over a 35-d period, NEX supplementation improved the feed conversion ratio (P = 0.02), reduced mortality rate (P = 0.01), and increased the European performance efficiency factor. No differences in carcass traits were observed between the 2 treatments (P > 0.05). Jejunal digestive enzyme activities, particularly those of amylase and lipase, were higher in NEX birds (P < 0.05) and correlated with morphometric parameters, such as villus height (P = 0.04) and muscular layer thickness (P < 0.01). Gene expression analysis revealed the upregulation of key genes related to nutrient transporters (solute carrier family 5 member 1 gene (SLC5A1), solute carrier family 1 member 1 gene (SLC1A1), solute carrier family 15 member 1 gene (SLC15A1)) in the jejunum (P < 0.05) and lipid metabolism (peroxisome proliferator-activated receptor alpha gene (PPARA) and microsomal triglyceride transfer protein gene (MTTP)) in the liver (P < 0.05) of NEX-supplemented birds. NEX treatment altered plasma biomarkers, including increased glucose (P < 0.01), insulin (P < 0.01), and protein profiles (P < 0.05) but decreased low-density lipoprotein cholesterol (P = 0.03), suggesting enhanced metabolic health. NEX supplementation improved growth performance, economic efficiency, intestinal morphology, digestive enzyme activity, liver function, and metabolic biomarkers in broiler chickens.

Prehatch thermal manipulation of embryos and posthatch baicalein supplementation increased liver metabolism, and muscle proliferation in broiler chickens

The exposure of broiler chickens to high ambient temperatures causes heat stress (HS), negatively affecting their health and production performance. To mitigate heat stress in broilers, various strategies, including dietary, managerial, and genetic interventions, have been extensively tested with varying degrees of efficacy. For sustainable broiler production, it is imperative to develop an innovative approach that effectively mitigates the adverse effects of HS. Our previous studies have provided valuable insights into the effects of prehatch embryonic thermal manipulation (TM) and posthatch baicalein supplementation on embryonic thermotolerance, metabolism, and posthatch growth performance. This follow-up study investigated the effect of these interventions on gluconeogenesis and lipid metabolism in the liver, as well as muscle proliferation and regeneration capacity in heat-stressed broiler chickens. A total of six-hundred fertile Cobb 500 eggs were incubated for 21 d. After candling, 238 eggs were subjected to TM at 38.5°C with 55% relative humidity (RH) from embryonic day (ED) 12 to 18. These eggs were transferred to the hatcher and kept at a standard temperature (37.5°C) from ED 19 to 21, while 236 eggs were incubated at a controlled temperature (37.5°C) till hatch. After hatching, 180 day-old chicks from both groups were raised in 36 pens treatment (n = 10 birds/pen, 6 replicates per treatment). The treatments were: 1) Control, 2) TM, 3) Control heat stress (CHS), 4) Thermal manipulation heat stress (TMHS), 5) Control heat stress supplement (CHSS), and 6) Thermal manipulation heat stress supplement (TMHSS). Baicalein was added to the treatment group diets starting from d 1. All birds were raised under the standard environment for 21 d, followed by chronic heat stress from d 22 to 35 (32-33 ⁰C for 8 h) in the CHS, TMHS, CHSS, and TMHSS groups. A thermoneutral (22-24⁰C) environment was maintained in the Control and TM groups. RH was constant (50 ± 5%) throughout the trial. In the liver, TM significantly increased (P < 0.05) IGF2 expression. Baicalein supplementation significantly increased (P < 0.05) HSF3, HSP70, SOD1, SOD2, TXN, PRARα, and GHR expression. Moreover, the combination of TM and baicalein supplementation significantly increased (P < 0.05) the expression of HSPH1, HSPB1, HSP90, LPL, and GHR. In the muscle, TM significantly increased (P < 0.05) HSF3 and Myf5 gene expression. TM and baicalein supplementation significantly increased (P < 0.05) the expression of MyoG and significantly (P < 0.05) decreased mTOR and PAX7. In conclusion, the prehatch TM of embryos and posthatch baicalein supplementation mitigated the deleterious effects of HS on broiler chickens by upregulating genes related to liver gluconeogenesis, lipid metabolism, and muscle proliferation.

Effects of oregano and/or rosemary extracts on growth performance, digestive enzyme activities, cecal bacteria, tight junction proteins, and antioxidants-related genes in heat-stressed broiler chickens

The study examined the impact of adding oregano extract and/or rosemary to broiler diets to counteract the growth inhibition caused by heat stress (HS). It also investigated the effects on the activity of digestive enzymes, microbiological composition, and the expression of antioxidant and tight junction-related proteins. Three hundred- and fifty-day-old male broilers, were randomly assigned to 7 treatment groups, with each group comprising 5 replicates, and each replicate containing 10 chicks in a cage. The diets were: 1) a basal diet, 2) a diet supplemented with 50 mg/kg of rosemary, 3) a diet supplemented with 100 mg/kg of rosemary, 4) a diet supplemented with 50 mg/kg of oregano, 5) a diet supplemented with 100 mg/kg of oregano, 6) a combination diet containing 50 mg/kg each of rosemary and oregano, and 7) a combination diet containing 100 mg/kg each of rosemary and oregano. Dietary oregano extract enhanced the growth and feed utilization of heat-stressed birds, especially at a concentration of 50 mg/kg. Moreover, oregano extract improved jejunal protease and amylase activities. The extracts of rosemary and oregano significantly reduced IgG and IgM levels. Dietary 50 mg oregano extract significantly upregulated intestinal integrity-related genes including jejunal CLDNI, ZO-1, ZO-2, and MUC2. Dietary 50 mg oregano extract significantly downregulated hepatic NADPH oxidase 4 (NOX4) and nitric oxide synthase 2 (NOS2) expressions. Our results suggest that incorporating oregano leaf extract into the diet at a concentration of 50 mg/kg improves the growth performance of broilers exposed to heat stress. This improvement could be attributed to enhanced gut health and the modulation of genes associated with oxidative stress and tight junction proteins.

Impact of in ovo feeding of grape pomace extract on the growth performance, antioxidant status, and immune response of hatched broilers

Delivering natural antioxidants via in ovo feeding holds promise for enhancing the antioxidant status and performance of chickens. Therefore, The objective of this study was to evaluate the impacts of in ovo feeding during early embryonic development using grape pomace extract as a natural antioxidant on hatchability, productive performance, immune response, and antioxidant status in broilers. A total of 900 fertile broiler eggs from the Arbor Acres strain were utilized. Each egg was individually weighed, with egg weights ranging from 61.88 ± 3 g. On the 17.5th d of incubation (DOI), the fertile eggs were divided into 6 groups. The first treatment group was untreated and designated as the control (C). The second group was the sham group (Sh), receiving a simulated injection. The third group, designated as the vehicle group (V), was injected with 100 µl of dimethyl sulfoxide (DMSO). The fourth group received an injection of 100 µL of grape pomace dissolved in DMSO at a concentration of 2 mg (T2). Similarly, the fifth and sixth groups were injected with 100 µL of grape pomace dissolved in DMSO at concentrations of 4 mg and 6 mg, (T4), (T6) respectively. Subsequently, all groups were raised under uniform conditions in terms of management, environment, and nutrition till 5 wk of age. The grape pomace extract (GPE), obtained is rich in total phenolic content (16.07 mg/g), total flavonoid content (7.42 mg/g), and total anthocyanin (8.37 mg/g). Grape pomace extract has exhibited significant antioxidant properties as evidenced by its effectiveness in DPPH scavenging and reducing power assays. Significant improvements in body weight at hatch were observed with in ovo feeding of grape pomace extract, particularly at the 4 mg level, surpassing the effectiveness of the 2 mg and 6 mg grape pomace levels, and this enhancement in body weight continued until the age of 5 wk. GPE injection also led to a significant reduction in cholesterol levels, with the lowest levels recorded for the T4 group. Plasma total Antioxidant Capacity (TAC) levels were significantly elevated in groups treated with T4, T6, and T2 compared to the control group. Conversely, the control group showed a significant increase (P < 0.01) in plasma malondialdehyde (MDA) levels. The immune response of hatched chicks from grape pomace extract-injected groups, especially the T4 group, exhibited improvement through increased IgM and IgG. These findings demonstrate that in ovo feeding of GPE, particularly at a dosage of 4 mg, enhances growth performance, immune response, and antioxidant status in hatched chicks. Thus, administering natural antioxidants, such as grape pomace extract, to developing broiler embryos via in ovo feeding could serve as a valuable strategy for enhancing the subsequent post-hatch productive performance, as well as bolstering the antioxidant and immunological status of broiler chicks.

Dietary pterostilbene exerts potential protective effects by regulating lipid metabolism and enhancing antioxidant capacity on liver in broilers

Intensive breeding of broilers met the increasing demands of human for broiler products, but it raised their increased susceptibility to various stressors resulting in the disorder of lipid metabolism. Pterostilbene, the methoxylated analogue of resveratrol, exhibits astonishing functions of antioxidant, anti-inflammatory and glycolipid regulatory. The study aimed to elucidate the protective effects of pterostilbene on broiler liver and to explore the potential mechanisms. A total of 480 one-day-old male Arbor Acres (AA) broilers were randomly divided into four groups: the control group (basal diet) and pterostilbene groups (PT200, PT400, and PT600 feeding with basal diet containing 200, 400 and 600 mg/kg pterostilbene, respectively). The results showed that the dietary pterostilbene supplementation significantly improved the ADG of broilers. Dietary pterostilbene supplementation regulated the expression levels of the genes Sirt1 and AMPK and the downstream genes related to lipid metabolism to protect liver function and reduce lipid accumulation in broilers. Dietary pterostilbene supplementation upregulated the expression levels of the Nrf2 gene and its downstream antioxidant genes (SOD, CAT, HO-1, NQO-1, GPX) and phase II detoxification enzyme-related genes (GST, GCLM, GCLC). Collectively, pterostilbene was confirmed the positive effects as a feed additive on lipid metabolism and antioxidant via regulating Sirt1/AMPK and Nrf2 signalling pathways in broilers.

Growth performance, histological and physiological responses of heat-stressed broilers in response to short periods of incubation during egg storage and thermal conditioning

The short periods of incubation during egg storage (SPIDES) method enhances the quality of chicks and improves hatching rates. Additionally, embryonic thermal conditioning (TC) is a technique used to enhance thermotolerance in birds. Previous studies have evaluated the effects of SPIDES and embryonic TC separately. Yet, our hypothesis postulated that a synergistic effect could be achieved by integrating TC and SPIDES, thereby enhancing the broilers' resilience to thermal stress. We conducted an experiment involving 800 Ross broiler eggs, divided into two groups. The first group, referred to as S0, was maintained under standard storage room conditions and acted as our control group. The second group, known as S1, underwent a process called SPIDES for 5 h at a temperature of 37.8 ± 0.1 °C, on three occasions: days 5, 10, and 15 following egg collection. Upon reaching the 14th day of incubation (DOI), each of these primary groups was randomly subdivided into two equal subgroups. The control subgroup, designated as TC0, remained in the usual incubation conditions. Meanwhile, the other subgroup, TC1, was subjected to prenatal heat conditioning at a temperature of 39.5 ± 0.1 °C for 6 h per day, commencing on the 14th embryonic day (E) and extending until the 18th embryonic day (E). This experimental setup resulted in four distinct experimental subgroups: S0TC0, S1TC0, S0TC1, and S1TC1. The findings indicated that the combined application of SPIDES and TC had a significant positive effect on chick performance after hatching. Specifically, the (S1TC1) group exhibited the heaviest live body weight (LBW) and body weight gain (BWG) at the marketing age in comparison to the other groups. Furthermore, both SPIDES and TC had a positive influence on the relative weights of breast muscles and their histological measurements. The (S1TC1) group displayed significantly higher values in terms of the relative weight of breast muscles and the number of myocytes. In conclusion, SPIDES and TC have beneficial effects on pre- and post-hatch characteristics of broiler chicks up until the marketing age. Additionally, TC techniques improve chick performance, particularly under conditions of heat stress, and enhance the yield of breast muscle in later stages of life.