Dietary puerarin supplementation improves immune function in the small intestines of oxidized oil-challenged broilers.

Puerarin has possessed a wide range of pharmacological activities. However, little is known about the protective effects of puerarin on the oxidized oil-induced injury. Here, we describe the anti-inflammatory effects of puerarin in chickens. A total of 360 broilers were arranged in four treatments. Diets included two types of soybean oil (fresh or oxidized) and two levels of puerarin (0 or 750 mg/kg). Results showed that puerarin alleviated oxidized soybean oil-induced intestinal immune injury by decreasing the expressions of HSP and pro-inflammatory factor (P < 0.05) and enhancing the mRNA levels of anti-inflammatory factor and CATH-1 (P < 0.05) in broilers. Moreover, puerarin supplementation decreased the mRNA abundances of TLR4 and MyD88 (P < 0.05) and upregulated the expressions of A20 and SOCS-1 (P < 0.05) in the small intestine of oxidized soybean oil-challenged broilers. Collectively, this study demonstrates puerarin may be a potential nutrient supplement in the treatment of oxidized oil-induced damage in poultry.

Tryptophan alleviates chronic heat stress-induced impairment of antioxidant capacities, inflammatory response, and mitochondrial function in broilers.

The aim of this study was to investigate the effect of dietary tryptophan (Trp) supplementation on serum biochemical indices, antioxidant indices, cytokine levels, mitochondrial biosynthesis, and mitochondrial morphology of heat-stressed broilers. A total of 180 female Arbor Acres broilers (18-day-old) were randomly allocated into three groups with six replicates of 10 broilers each. Broilers in thermoneutral (TN) (23 ± 1 °C) group were fed a basal diet; the other two groups were fed the basal diet supplemented with 0 or 0.18% Trp under heat stress (HS) (34 ± 1 °C for 8 h/day (h/day) and 23 ± 1°C for the remaining time) condition. The heat stress lasted for 21 days (days 21 to 42). The results indicated that heat stress reduced serum total protein content (TP) and decreased the activities of serum superoxide dismutase (SOD) and total antioxidant capacity (T-AOC), but increased the levels of serum uric acid (UA), interleukin (IL)-1ß, IL-6, and IL-18 (P < 0.05) compared to the TN group. However, dietary supplementation with 0.18% Trp enhanced serum TP content, glutathione peroxidase (GSH-Px), SOD, catalase (CAT) activities, and T-AOC; decreased aspartate aminotransferase (AST) activities (P < 0.05); and lowered serum IL-1ß, IL-6, IL-18 contents (P < 0.05). Meanwhile, heat stress exposure downregulated the mRNA expression of mitochondrial transcription factor A (TFAM), cytochrome c oxidase subunit 1 (COX1), and cytochrome c oxidase subunit 5A (COX5A) in ileum (P < 0.05) as compared to the TN group. Dietary Trp supplementation enhanced the mitochondrial membrane potential (MMP) and the mRNA expression of TFAM, COX1 in ileum mucosa (P < 0.05) and ameliorated the damage of mitochondrial structure. Collectively, dietary supplementation with Trp could improve antioxidant capacity and mitochondrial structure and regulate mitochondrial function-related genes and decrease inflammatory response in heat-stressed broilers. Dietary Trp supplementation might be an effective nutritional strategy to protect against heat stress impairment.

Effects of dietary tryptophan supplementation on rectal temperature, humoral immunity, and cecal microflora composition of heat-stressed broilers.

This trial aimed to determine the effects of tryptophan (Trp) on the rectal temperature, hormone, humoral immunity, and cecal microflora composition in broiler chickens under heat stress (HS). One hundred and eighty 18 days-old female Arbor Acres broilers were randomly divided into three treatment groups, with six replicates of ten birds in each replicate. The broilers were either raised under thermoneutral conditions (TN, 23 ± 1°C) or subjected to heat stress (34 ± 1°C for 8 h daily). The TN group received a basal diet, and another two heat-stressed groups were fed the basal diet (HS) or the basal diet supplemented with 0.18% Trp (HS + 0.18% Trp) for 21 consecutive days. The basal diet contained 0.18% Trp. Results revealed that HS increased the rectal temperature, serum epinephrine (EPI), and corticotropin-releasing hormone (CRH) concentrations (p < 0.05), reduced the bursal index, the levels of serum immunoglobulin A (IgA), IgG, IgM, and serotonin (5-HT) as well as the relative abundance of Actinobacteria in cecum (p < 0.05) compared with the TN group. Dietary supplementation of Trp decreased the rectal temperature, serum dopamine (DA), EPI, and the levels of CRH and L-kynurenine (p < 0.05), increased the bursal index, the levels of serum IgA, IgM, and 5-HT as well as the relative abundance of Ruminococcus torques group in cecum of heat-stressed broilers (p < 0.05) compared to HS group. In conclusion, dietary Trp supplementation decreased rectal temperature, improved cecal microbiota community and Trp metabolism, and enhanced humoral immunity of heat-stressed broilers.

Puerarin Alleviates Oxidized Oil-Induced Oxidative Injury and Inflammation via Inhibition of the Nrf2/Keap1 and HMGB1/TLR4/MAPK Signaling Pathways: An Investigation in a Chicken Model.

SCOPE: Puerarin has possessed a wide range of pharmacological activities. However, little is known about the protective effects of puerarin on the oxidized oil-induced injury. Here, the antioxidant and anti-inflammatory effects of puerarin are described using a chicken model. METHODS AND RESULTS: A total of 360 broilers are arranged in four treatments. Diets include two types of soybean oil (fresh or oxidized) and two levels of puerarin (0 or 750 mg kg-1 ). Results show that puerarin alleviates oxidized soybean oil-induced hepatic and thymic oxidative injury. This effect is observed by increasing the SOD activity and the expressions of Nrf2 signaling pathway-related genes and reducing the MDA content in the liver and thymus. Moreover, puerarin supplementation decreases the concentrations and mRNA levels of pro-inflammatory factors in the liver and thymus. The potential mechanism responsible for this is the decrease in the mRNA or protein levels of HMGB1, TLR4, MyD88, and p65 in the liver or thymus. Western blotting results indicate that puerarin also decreases the phosphorylation of JNK1/2, ERK1/2, and p38 in the liver and thymus. CONCLUSION: This study demonstrates puerarin may be a potential nutrient supplement in the treatment of oxidized oil-induced damage, and the Nrf2/Keap1 and HMGB1/TLR4/MAPK signaling pathways might be its important target.

Tryptophan Alleviates Acute Heat Stress-Induced Impairment of Antioxidant Status and Mitochondrial Function in Broilers.

Heat stress has been considered as a critical risk factor for decreasing performance and causing oxidative stress in broilers. The tryptophan (TRP) derivative 5-hydroxytryptophan has been reported to protect membrane fluidity in broilers suffering from oxidative stress. Therefore, this experiment was conducted to investigate the effects of dietary TRP supplementation on antioxidant status and mitochondrial function-related genes expressions in broilers exposed to acute heat stress (34 ± 1°C, 24 h). Female Arbor Acres broilers (19-d-old, n = 180) were randomly assigned to 1 of 3 treatments. Broilers were fed a basal diet and in the thermoneutral conditions (TN, 23 ± 1°C) was considered as the TN group. Broilers were fed a basal diet and exposed to acute heat stress (HS, 34 ± 1°C) was regarded as the HS group. Broilers were fed a basal diet supplemented with 0.18% L-tryptophan and under HS conditions was treated as the HS + TRP groups. Heat stress led to increased malondialdehyde (MDA) concentration (P < 0.05), while it elevated catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and total antioxidant capacity activities (T-AOC) (P < 0.05) compared with the TN group. Nevertheless, compared with the HS group, TRP supplementation increased SOD activity (P < 0.05). The effects of acute heat stress were associated with increased mRNA abundance for redox-related genes (P < 0.05), and reduced mRNA levels for mitochondrial function-related genes (P < 0.05). Notably, the effects of acute heat stress on mitochondrial function-related genes expressions were reversed by TRP treatment. Collectively, dietary 0.18% TRP supplementation beneficially protects against acute heat stress-induced oxidation stress and mitochondrial dysfunction by regulating antioxidant states and increasing mitochondrial function-related genes expressions in broilers.

Effects of dietary tryptophan supplementation on body temperature, hormone, and cytokine levels in broilers exposed to acute heat stress.

The present study was conducted to investigate the effects of tryptophan (Trp) supplementation on rectal temperature, hormone, and cytokine levels in broilers subjected to acute heat stress. A total of 300 18-day-old female Arbor Acres broilers were randomly allocated to five dietary treatment groups with six replicates per treatment group and ten birds per replicate. Broilers were fed a basal diet and in the thermoneutral conditions (TN, 23 ± 1 °C) was considered as the TN group. Broilers were fed a basal diet and exposed to acute heat stress (HS, 34 ± 1 °C) was regarded as the HS group, and other broilers exposed to acute heat stress (34 ± 1°C) were fed a basal diet supplemented with 0.09%, 0.18%, and 0.27% Trp. Results indicated that acute heat stress increased the rectal temperature (P < 0.05), enhanced the concentrations of corticosterone (CORT), dopamine (DA), adrenaline (Adr), adrenocorticotropic hormone (ACTH), and corticotropin-releasing hormone (CRH) in serum (P < 0.05), and elevated the levels of serum tryptophan hydroxylase (TPH)1, tryptophan 2, 3-dioxygenase (TDO), indoleamine 2, 3-dioxygenase (IDO), and kynurenic acid (P < 0.05), compared with the TN group. Meanwhile, acute heat stress increased the levels of serum Trp, hypothalamic Trp, 5-hydroxytryptophan (5-HT), and interleukin-22 (P < 0.05) relative to the TN group. However, compared with the heat stress group, Trp supplementation decreased the rectal temperature of heat-stressed broilers and dietary 0.09% Trp supplementation decreased the levels of serum CRH and TDO (P < 0.05), increased the levels of serum Trp and IL-22 (P < 0.05) in heat-stressed broilers. In addition, dietary supplemented with 0.18% Trp reduced the levels of serum DA, Adr, noradrenaline (NA), CRH, TDO, IDO, kynurenic acid, IL-1ß, and hypothalamic 5-HIAA/5-HT (P < 0.05), increased the levels of serum Trp, 5-HT, and IL-22, and upregulated the concentrations of hypothalamic Trp and 5-HT in heat-stressed broilers (P < 0.05). Moreover, dietary 0.27% Trp supplementation decreased the levels of serum DA, CRH, TDO, and hypothalamic 5-HIAA/5-HT (P < 0.05), and upregulated the levels of serum Trp, 5-HT, IL-22, hypothalamic Trp and 5-HT in heat-stressed broilers (P < 0.05). Taken together, dietary 0.18% Trp supplementation may be the optimal level for broilers reared under acute heat stress.

Effect of probiotic supplementation on the expression of tight junction proteins, innate immunity-associated genes, and microbiota composition of broilers subjected to cyclic heat stress.

This study investigated the effects of probiotic on intestinal innate immunity-associated gene expression and cecal microbiota in heat-stressed broilers. A total of 180 21-day-old male broilers were randomly assigned to three treatment groups with four replicates per group. The thermoneutral group (TN) (23 ± 1°C) received a basal diet, and another two heat-stressed groups (28-35-28°C for 12 h daily) were fed the basal diet (HS) or the basal diet supplemented with probiotic at a dose of 1.5 × 108 CFU/kg (HS_Pro) for 21 consecutive days. Compared with the TN group, the abundance of beneficial bacteria was decreased (p < 0.05) in the caecum of heat-stressed broilers. Heat stress downregulated (p < 0.05) the expression of Toll-like receptor (TLR)2 and upregulated (p < 0.05) the expressions of TLR5, TLR15, avian ß-defensin (AvBD)4, AvBD8, and AvBD14 in the ileum as compared with the TN group. Dietary supplementation of probiotic upregulated (p < 0.05) the occludin expression in the ileum, improved the microbiota balance in the caecum, and decreased (p < 0.05) the gene expressions of TLR5 and TLR15 in the ileum of heat-stressed broilers. Collectively, dietary probiotic supplementation could promote intestinal barrier function via improving gut microbiota community and regulating innate immunity-associated gene expressions in heat-stressed broilers.