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

The effect of dietary supplementation of Lycium barbarum leaves on the growth performance, organ indexes and intestinal microflora of rats

This study was conducted to investigate both fruit and different levels of leaf supplementation on the growth performance, organ indices and intestinal microflora of rats. Twenty-five healthy male Sprague-Dawley rats were randomly divided into five groups. The rats in the control (NC) and positive control (PC) groups were fed by gavage a basal diet and a basal diet with 4 g/kg of L. barbarum fruit homogenate, respectively. The test (LD, MD, and HD) groups were fed basal diets with additional 2, 4, and 8 g/kg of L. barbarum leaf homogenate, respectively. The feeding period was 35 d. The result revealed that the rats in the LD group had the highest average weight gain (p < 0.05). The cardiac and renal indexes in the LD and MD groups were significantly higher than in NC group, respectively (p < 0.05). Diversity analysis revealed that adding low concentrations of L. barbarum leaf homogenates markedly reduced the Shannon index of the rats cecum (p < 0.05). The relative abundance of Verrucomicrobiota was higher in the LD group than those in other groups (p < 0.05). The relative abundance of Actinobacteriota was found significantly higher in PC group than others (p < 0.05). The relative abundance of Akkermansia in LD group was the highest (p < 0.05). The relative abundance of Romboutsia in the PC group was considerably higher than that in other groups. The relative abundance of Candidatus_Saccharimonas in the supplementation groups was appreciably lower than those found in other groups. The relative abundance of Alloprevotella was significantly lower in PC, LD, and MD groups than in NC and HD groups (p < 0.05). The relative abundance of Oscillibacter was significantly higher in HD group than in other groups (p < 0.05). Thus, L. barbarum leaf homogenate fed to rats could increase their growth performance, internal organ weights and additionally enhance the relative abundance of beneficial bacteria. Therefore, based on the obtained data in the current study, a dose of L. barbarum leaf homogenate supplemented with 2 g/kg in diet is recommended, however, further studies are required to confirm, especially in animals.

Extraction and immunomodulatory effects of acid Lagenaria siceraria (Molina) Standl. Polysaccharide on chickens

Herbal polysaccharides are extensively studied as vaccine adjuvants due to their safety and potent immunoenhancing activity. This study aimed to analyze the structure of Lagenaria siceraria (Molina) Standl polysaccharide (LSP50) and investigate its adjuvant activity for the H9N2 vaccine in broiler chickens. Structural analysis revealed that LSP50 primarily consisted of rhamnose, arabinose, xylose, mannose, glucose, and galactose with molar ratios of 23.12: 12.28: 10.87: 8.26: 2.64: 22.82 respectively. The adjuvant activity of LSP50 was evaluated, which showing significant enhancements compared to the H9N2 group. Parameters including the immune organ index, H9N2 specific IgG level, cytokines contents (IFN-γ, IL-2, IL-4, and IL-5), and the proportion of CD3e+CD8aT+cells were significantly increased in the LSP50 group (P < 0.05). Additionally, sequencing results showed that LSP50 modulates the immune response by regulating PLA2G12B and PTGDS genes involved in the arachidonic acid pathway. These findings were further validated through qPCR analysis to affirm the reliability of the sequencing data. In conclusion, our results demonstrate that LSP50 exhibits potent adjuvant activity, enhancing both cellular and humoral immunity.

Effect of genotype and nutritional and environmental challenges on growth curve dynamics of broiler chickens

The present study aimed to compare the dynamics of growth of various chicken genotypes exposed to heat stress, low-input diets, and free-range farming by using Gompertz model to gain insights into their capabilities to face environmental and nutritional challenges. Three in vivo trials (T1: heat stress, T2: low-input diets, and T3: free-range system) were conducted, involving a total of 671 animals. Five chicken genotypes were employed in each trial: 2 Italian local breeds, Bionda Piemontese (BP) and Robusta Maculata (RM), along with their crossbreeds with Sasso hens (BP×SA and RM×SA), and a commercial hybrid (Ross 308). One-day-old male chicks were individually identified, and the 5 genotypes were randomly allocated to different challenging conditions: T1 involved 2 environmental temperatures (thermoneutral vs. high temperature); T2 involved 2 diets (standard vs. low-input); T3 involved 2 rearing systems (conventional vs. free-range). The chickens were weighed once a week from their arrival until slaughtering, and the data were used to build growth curves using the Gompertz model. Chickens from different genotypes were slaughtered at varying ages based on their maturity. In all trials, the challenging conditions significantly reduced adult body weight (A; -31.0%) and maximum growth rate (MGR; -25.6%) of Ross chickens. In contrast, in T1 and T2, no significant changes were observed in the main growth curve parameters of local breeds and crossbreeds, while under free-range conditions, there was even an increase in the A and MGR of these genotypes. The crossbreeding was effective in increasing A and MGR of BP (+30.5% in BP×SA), as well as in improving the precocity and MGR of RM (+19.5% in RM×SA). Our findings highlight the effectiveness of the Gompertz model as a tool for evaluating birds' adaptability and confirm the greater ability of local breeds and crossbreeds to adapt to different challenges. In conclusion, our methodological approach could be used to choose the genotype most suited to the environmental context and confirm the potential advantages of crossbreeding for enhancing resilience and sustainability.

Optimizing growth and antioxidant function in heat-stressed broilers with vitamin C and betaine supplementation

This study investigates the potential of vitamin C (VC) and/or betaine (Bet) to enhance growth performance, regulate serum metabolism, and bolster antioxidant function aiming to mitigate the impact of heat stress (HS) on broilers. Two hundred Ross 308 broilers at 28 days of age were randomly assigned to five groups. The control group, housed at 24 ± 1℃, was fed a basal diet. High-temperature treatment groups, housed at 32 ± 1℃, received a basal diet with 0 (HS group), 250 mg/kg VC (HSVC group), 1000 mg/kg Bet (HSBe group), and 250 mg/kg VC + 1000 mg/kg Bet (HSVCBe group). On day 42, assessments were made on growth performance, muscle quality, serum biochemistry, and antioxidant function. Results revealed that HS significantly lowered (P < 0.05) average daily feed intake (ADFI), the degree of redness (a*) in muscles, and serum total superoxide dismutase (T-SOD) level. It also reduced (P < 0.01) average daily gain (ADG), and serum total antioxidant capacity (T-AOC) level, while increasing (P < 0.05) shear force, serum direct bilirubin (D-BIL), uric acid (UA), and malondialdehyde (MDA) levels compared with the control group. Dietary supplementation of VC and Bet, either alone or in combination, significantly decreased shear force and serum UA level, while increasing ADG and serum T-AOC, T-SOD level compared with the HS group (P < 0.05). In conclusion, the addition of VC and/or Bet to the diet proves effective in enhancing the growth performance of HS-exposed broilers through the positive regulation of serum chemical metabolism and the alleviation of oxidative damage.

Maternal exposure to particulate matter from duck houses restricts fetal growth due to inflammatory damage and oxidative stress

The composition of particulate matter (PM) in poultry farms differs significantly from that of atmospheric PM as there is a higher concentration of microbes on farms. To assess the health effects of PM from poultry farms on pregnant animals, we collected PM from duck houses using a particulate sampler, processed it via centrifugation and vacuum concentration, and subsequently exposed the mice to airborne PM at 0.48 mg/m3 (i.e., low concentration group) and 1.92 mg/m3 (i.e., high concentration group) on the fifth day of pregnancy. After exposure until the twentieth day of pregnancy or spontaneous delivery, mice were euthanized for sampling. The effects of PM from duck houses on the pregnancy toxicity of mice were analyzed using histopathological analysis, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction (qPCR). The results showed that exposure to PM had adverse effects on pregnant mice that reduced their feed intake in both groups. Microscopic lesions were observed in the lungs and placentas of pregnant mice, and the lesions worsened with increased PM concentrations, as shown by alveolar wall thickening, the infiltration of inflammatory cells in pulmonary interstitium, congestion, edema, and cellular degeneration of placenta. In pregnant mice in the high concentration group, exposure to PM significantly increased the expression of inflammatory cytokines in the lungs and placentas, caused oxidative stress, and decreased estrogen level in the blood. Exposure to PM also resulted in the reduced litter sizes of pregnant mice and shorter body and tail lengths in the fetuses delivered. Beyond that, exposure to PM significantly downregulated the levels of antioxidant factor superoxide dismutase and neurotrophic factor Ngf in the brains of fetuses. Collectively, exposure to a high concentration of PM by inhalation among pregnant mice caused significant pregnancy toxicity that led to abnormal fetal development due to inflammatory damage and oxidative stress. These findings established a foundation for future studies on the underlying mechanisms of pregnancy toxicity induced by exposure to PM.

Carboxymethylated Abrus cantoniensis polysaccharide prevents CTX-induced immunosuppression and intestinal damage by regulating intestinal flora and butyric acid content

As a Chinese folk health product, Abrus cantoniensis exhibits good immunomodulatory activity because of its polysaccharide components (ACP), and carboxymethylation of polysaccharides can often further improve the biological activity of polysaccharides. In this study, we explored the impact of prophylactic administration of carboxymethylated Abrus cantoniensis polysaccharide (CM-ACP) on immunosuppression and intestinal damage induced by cyclophosphamide (CTX) in mice. Our findings demonstrated that CM-ACP exhibited a more potent immunomodulatory activity compared to ACP. Additionally, CM-ACP effectively enhanced the abundance of short-chain fatty acid (SCFA)-producing bacteria in immunosuppressed mice and regulated the gene expression of STAT6 and STAT3 mediated pathway signals. In order to further explore the relationship among polysaccharides, intestinal immunity and intestinal flora, we performed a pseudo-sterile mouse validation experiment and fecal microbiota transplantation (FMT) experiment. The findings suggest that CM-FMT and butyrate attenuate CTX-induced immunosuppression and intestinal injury. CM-FMT and butyrate show superior immunomodulatory ability, and may effectively regulate intestinal cell metabolism and repair the damaged intestine by activating STAT6 and STAT3-mediated pathways. These findings offer new insights into the mechanisms by which CM-ACP functions as functional food or drug, facilitating immune response regulation and maintaining intestinal health.

Effects of medical plants on alleviating the effects of heat stress on chickens

Over the past decades, global climate change has led to a significant increase in the average ambient temperature causing heat stress (HS) waves. This increase has resulted in more frequent heat waves during the summer periods. HS can have detrimental effects on poultry, including growth retardation, imbalance in immune/antioxidant pathways, inflammation, intestinal dysfunction, and economic losses in the poultry industry. Therefore, it is crucial to find an effective, safe, applicable, and economically efficient method for reducing these negative influences. Medicinal plants (MPs) contain various bioactive compounds with antioxidant, antimicrobial, anti-inflammatory, and immunomodulatory effects. Due to the biological activities of MPs, it could be used as promising thermotolerance agents in poultry diets during HS conditions. Nutritional supplementation with MPs has been shown to improve growth performance, antioxidant status, immunity, and intestinal health in heat-exposed chickens. As a result, several types of herbs have been supplemented to mitigate the harmful effects of heat stress in chickens. Therefore, several types of herbs have been supplemented to mitigate the harmful effects of heat stress in chickens. This review aims to discuss the negative consequences of HS in poultry and explore the use of different traditional MPs to enhance the health status of chickens.

Viola yedoensis Makino alleviates heat stress-induced inflammation, oxidative stress, and cell apoptosis in the spleen and thymus of broilers

ETHNOPHARMACOLOGICAL RELEVANCE

Viola yedoensis Makino (VYM) is a traditional Chinese herbal medicine widely distributed in China. It has many pharmacological effects such as anti-inflammatory, immune regulation and anti-oxidation. However, the protective effect of VYM on the spleen and thymus of broilers induced by heat stress has rarely been reported.

AIM OF THE STUDY

We established a heat stress model of broilers to explore the protective effect of VYM on spleen and thymus of broilers.

MATERIALS AND METHODS

In this experiment, a heat stress model was made by adjusting the feeding temperature of broilers. The protective effect of VYM on the spleen and thymus of heat-stressed broilers were evaluated by detecting immune organ coefficient, histological observation, Enzyme-Linked Immunosorbent Assay, production of antioxidant enzymes and peroxides, TUNEL Staining, Quantitative Real-time PCR.

RESULTS

In this study, 60 healthy male AA broilers were divided into 6 groups: Control, 4.5% VYM, HS, HS + 0.5% VYM, HS + 1.5% VYM, HS + 4.5% VYM. After 42 days of feeding, serum, spleen and thymus were collected for detection and analysis. The study revealed that heat stress can lead to pathological damage in the spleen and thymus of broilers, reduce the content of immunoglobulin and newcastle disease (ND), infectious bursal disease (IBD) antibody levels, increase the expression of inflammatory factors IL-1β, INF-γ, heat shock 70 kDa protein (HSP70), heat shock 90 kDa protein (HSP90). Heat stress inhibits the activity of antioxidant enzymes CAT and SOD, promotes the production of MDA, and then lead to oxidative damage of the spleen and thymus. In addition, apoptotic cells and the ratio of Bax/Bcl-2 was increased. However, the addition of VYM to the feed can alleviate the adverse effects of heat stress on the spleen and thymus of broilers.

CONCLUSIONS

This study showed that the addition of VYM to the diet could inhibit oxidative stress and apoptosis, and reduce the inflammatory damage of heat stress on the spleen and thymus of broilers. This study provides a basis for further exploring the regulatory role of VYM in heat stress-induced immune imbalance in broilers. In addition, this study also provides a theoretical basis for the development of VYM as a feed additive with immunomodulatory effects.

Effects of guanidinoacetic acid supplementation on growth performance, hypothalamus-pituitary-adrenal axis, and immunity of broilers challenged with chronic heat stress

Heat stress can cause systemic immune dysregulation and threaten the health of broilers. Guanidinoacetic acid (GAA) has been shown to be effective against heat stress, but whether it is beneficial for immunity is unclear. Therefore, the effects of dietary GAA supplementation on the immunity of chronic heat-stressed broilers were evaluated. A total of 192 Arbor Acres male broilers (28-day old) were randomly allocated to 4 treatments: the normal control group (NC, 22°C, ad libitum feeding), the heat stress group (HS, 32°C, ad libitum feeding), the pair-fed group (PF, kept at 22°C and received food equivalent to that consumed by the HS group on the previous day), and the GAA group (HG, 32°C, ad libitum feeding; basal diet supplemented with 0.6 g/kg GAA). Samples were collected on d 7 and 14 after treatment. Results showed that broilers exposed to heat stress exhibited a decrease (P < 0.05) in ADG, ADFI, thymus and bursa of Fabricius indexes, and an increase (P < 0.05) in feed conversion ratio and panting frequency, compared to the NC group. Levels of corticotropin-releasing factor, corticosterone (CORT), heat shock protein 70 (HSP70), IL-6, and TNF-α were elevated (P < 0.05) while lysozyme and IgG concentration was decreased (P < 0.05) in the HS group compared with the NC group after 7 d of heat exposure. The concentrations of IgG and IL-2 were decreased (P < 0.05) and CORT was increased (P < 0.05) in the HS group compared with the NC group after 14 d of heat exposure. Noticeably, GAA supplementation decreased the levels of CORT (P < 0.05) and increased the IL-2, IgG, and IgM concentrations (P < 0.05) compared with the HS group. In conclusion, chronic heat stress increased CORT release, damaged immune organs, and impaired the immunity of broilers. Dietary supplementation of 0.6 g/kg GAA can reduce the CORT level and improve the immune function of broilers under heat stress conditions.

Heat stress and poultry production: a comprehensive review

The impact of global warming on poultry production has gained significant attention over the years. However, our current knowledge and understanding of the mechanisms through which heat stress (HS) resulting from global warming affects the welfare, behavior, immune response, production performance, and even transgenerational effects in poultry are still incomplete. Further research is needed to delve deeper into these mechanisms to gain a comprehensive understanding. Numerous studies have investigated various biomarkers of stress in poultry, aiming to identify reliable markers that can accurately assess the physiological status and well-being of birds. However, there is a significant amount of variation and inconsistency in the results reported across different studies. This inconsistency highlights the need for more standardized methods and assays and a clearer understanding of the factors that influence these biomarkers in poultry. This review article specifically focuses on 3 main aspects: 1) the neuroendocrine and behavioral responses of poultry to HS, 2) the biomarkers of HS and 3) the impact of HS on poultry production that have been studied in poultry. By examining the neuroendocrine and behavioral changes exhibited by poultry under HS, we aim to gain insights into the physiological impact of elevated temperatures in poultry.

Heat stress exposure cause alterations in intestinal microbiota, transcriptome, and metabolome of broilers

Introduction

Heat stress can affect the production of poultry through complex interactions between genes, metabolites and microorganisms. At present, it is unclear how heat stress affects genetic, metabolic and microbial changes in poultry, as well as the complex interactions between them.

Methods

Thus, at 28  days of age a total of 200 Arbor Acres broilers with similar body weights were randomly divided into the control (CON) and heat stress treatment (HS). There were 5 replicates in CON and HS, respectively, 20 per replication. From the 28-42  days, the HS was kept at 31 ± 1°C (9:00-17:00, 8 h) and other time was maintained at 21 ± 1°C as in the CON. At the 42nd day experiment, we calculated the growth performance (n = 8) of broilers and collected 3 and 6 cecal tissues for transcriptomic and metabolomic investigation and 4 cecal contents for metagenomic investigation of each treatment.

Results and discussion

The results indicate that heat stress significantly reduced the average daily gain and body weight of broilers (value of p < 0.05). Transcriptome KEGG enrichment showed that the differential genes were mainly enriched in the NF-kB signaling pathway. Metabolomics results showed that KEGG enrichment showed that the differential metabolites were mainly enriched in the mTOR signaling pathway. 16S rDNA amplicon sequencing results indicated that heat stress increased the relative abundance of Proteobacteria decreased the relative abundance of Firmicutes. Multi-omics analysis showed that the co-participating pathway of differential genes, metabolites and microorganisms KEGG enrichment was purine metabolism. Pearson correlation analysis found that ornithine was positively correlated with SULT1C3, GSTT1L and g_Lactobacillus, and negatively correlated with CALB1. PE was negatively correlated with CALB1 and CHAC1, and positively with g_Alistipes. In conclusion, heat stress can generate large amounts of reactive oxygen and increase the types of harmful bacteria, reduce intestinal nutrient absorption and antioxidant capacity, and thereby damage intestinal health and immune function, and reduce growth performance indicators. This biological process is manifested in the complex regulation, providing a foundational theoretical basis for solving the problem of heat stress.

The effects of essential oil from Lippia origanoides and herbal betaine on performance, intestinal integrity, bone mineralization and meat quality in broiler chickens subjected to cyclic heat stress

Essential oils (EO) affect performance, intestinal integrity, bone mineralization, and meat quality in broiler chickens subjected to cyclic heat stress (HS). Day-of-hatch Cobb 500 male broiler chicks (n = 475) were randomly divided into four groups. Group 1: No heat stress (Thermoneutral) + control diets with no antibiotics; Group 2: heat stress control + control diets; Group 3: heat stress + control diets supplemented with thymol chemotype (45 ppm) and herbal betaine (150 ppm) formulation EO1; Group 4: heat stress + control diets supplemented with phellandrene (45 ppm) and herbal betaine (150 ppm) formulation EO2. From day 10-42, the heat stress groups were exposed to cyclic HS at 35°C for 12 h (8:00-20:00). BW, BWG, FI, and FCRc were measured at d 0, 10, 28, and 42. Chickens were orally gavaged with FITC-d on days 10 (before heat stress) and 42. Morphometric analysis of duodenum and ileum samples and bone mineralization of tibias were done. Meat quality was assessed on day 43 with ten chickens per pen per treatment. Heat stress reduced BW by day 28 (p < 0.05) compared to thermoneutral chickens. At the end of the trial, chickens that received both formulations of EO1 and EO2 had significantly higher BW than HS control chickens. A similar trend was observed for BWG. FCRc was impaired by EO2 supplementation. There was a significant increase in total mortality in EO2 compared with EO1 EO1 chickens had lower FITC-d concentrations at day 42 than the HS control. In addition, EO1 treatment is not statistically different if compared to EO2 and thermoneutral. Control HS broilers had significantly lower tibia breaking strength and total ash at day 42 than heat-stressed chickens supplemented with EO1 and EO2. Heat stress affected intestinal morphology more than thermoneutral chickens. EO1 and EO2 improved intestinal morphology in heat-stressed chickens. Woody breast and white striping were more common in thermoneutral chickens than heat stress chickens. In conclusion, the EO-containing diet could improve broiler chicken growth during cyclic heat stress, becoming increasingly relevant in antibiotic-free production in harsh climates.