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

Effects of Bacillus subtilis and Lactobacillus on growth performance, serum biochemistry, nutrient apparent digestibility, and cecum flora in heat-stressed broilers

This study investigates the effect of dietary Bacillus subtilis and Lactobacillus on the growth performance, serum biochemistry, nutrient apparent digestibility, and cecum flora of broilers under heat stress (HS) and provides a theoretical basis for the application of probiotic additives to alleviate the stress of poultry under HS. A total of 200 Cobb broilers were randomly assigned to four replicates of 10 broilers in each of the five groups. The growth performance, serum biochemistry, nutrient apparent digestibility, and cecum flora of broilers were detected on the 28th, 35th, and 42nd days, respectively. Results revealed that HS can affect the growth performance and serum biochemical indexes of broilers, lowered the number of intestinal bifidobacteria and Lactobacillus, and increase the number of Escherichia coli in comparsion to the CON group. Compared with the HS group, the ADFI of HS broilers in the BS group and the combined group significantly increased (P < 0.05) at 22-28 days of age, and the serum calcium and phosphorus increased (P < 0.05) significantly at 42 days of age. Meanwhile, the number of Lactobacillus in the BS group and LAB group increased significantly at 42 days of age (P < 0.05). The number of Escherichia coli in the LAB group and combination group decreased significantly at 35 days of age (P < 0.01). The present study revealed that the addition of Bacillus subtilis or Lactobacillus to diets increased ADFI, increased probiotic counts, and lowered Escherichia coli counts in HS broilers, while probiotics alone work well.

Dietary Zn proteinate with moderate chelation strength alleviates heat stress-induced intestinal barrier function damage by promoting expression of tight junction proteins via the A20/NF-κB p65/MMP-2 pathway in the jejunum of broilers

BACKGROUND

The aim of this study was to determine whether and how Zn proteinate with moderate chelation strength (Zn-Prot M) can alleviate heat stress (HS)-induced intestinal barrier function damage of broilers. A completely randomized design was used for comparatively testing the effects of Zn proteinate on HS and non-HS broilers. Under high temperature (HT), a 1 (Control, HT-CON) + 2 (Zn source) × 2 (added Zn level) factorial arrangement of treatments was used. The 2 added Zn sources were Zn-Prot M and Zn sulfate (ZnS), and the 2 added Zn levels were 30 and 60 mg/kg. Under normal temperature (NT), a CON group (NT-CON) and pair-fed group (NT-PF) were included.

RESULTS

The results showed that HS significantly reduced mRNA and protein expression levels of claudin-1, occludin, junctional adhesion molecule-A (JAMA), zonula occludens-1 (ZO-1) and zinc finger protein A20 (A20) in the jejunum, and HS also remarkably increased serum fluorescein isothiocyanate dextran (FITC-D), endotoxin and interleukin (IL)-1β contents, serum diamine oxidase (DAO) and matrix metalloproteinase (MMP)-2 activities, nuclear factor kappa-B (NF-κB) p65 mRNA expression level, and protein expression levels of NF-κB p65 and MMP-2 in the jejunum. However, dietary supplementation with Zn, especially organic Zn as Zn-Prot M at 60 mg/kg, significantly decreased serum FITC-D, endotoxin and IL-1β contents, serum DAO and MMP-2 activities, NF-κB p65 mRNA expression level, and protein expression levels of NF-κB p65 and MMP-2 in the jejunum of HS broilers, and notably promoted mRNA and protein expression levels of claudin-1, ZO-1 and A20.

CONCLUSIONS

Our results suggest that dietary Zn, especially 60 mg Zn/kg as Zn-Prot M, can alleviate HS-induced intestinal barrier function damage by promoting the expression of TJ proteins possibly via induction of A20-mediated suppression of the NF-κB p65/MMP-2 pathway in the jejunum of HS broilers.

Effects of Ban Lian Zi Jin San on intestinal inflammation and barrier function of heat-stressed broilers

Heat stress (HS) in broilers can be an environmental stressor that leads to intestinal inflammation and intestinal barrier damage. In order to examine the effect of Ban Lian Zi Jin San (BLZJS) on intestinal inflammation and barrier function in heat-stressed broilers, a model of chronic cyclic HS in broilers was established. A total of 300 twenty-one-day-old broilers were divided into 5 treatments at random. Broilers in 3 BLZJS dosage groups were kept in an ecologically controlled room at 37℃ ± 2℃ for 6 wk, and fed basal diets supplemented with 0.5, 1, and 2% BLZJS. Broilers in HS group were housed in the same room, but fed the basal diets. The findings indicated that supplementation of BLZJS significantly declined serum HS indexes levels (HSP70, HSP90), and increased serum antioxidant capacity (SOD and T-AOC) in broilers (P < 0.05). Besides, supplementation of BLZJS significantly inhibited the expression of HS indexes (HSP70 and HSP90), genes related to TLR4 inflammatory signal pathway (TLR4, MyD88, TRIF, IRAK-4, and NF-κB), inflammatory factors (IL-6 and TNF-α), and upregulated anti-inflammatory cytokines (IL-10) and intestinal tight junction-related genes (Occludin, Claudin-1, and ZO-1) in broiler jejunum (P < 0.05). On the other hand, supplementation of BLZJS could significantly reduce the protein expression of NF-κB and HSP70 in chick jejunum (P < 0.05). In conclusion, BLZJS inhibited the activation of TLR4 signal pathway and reduced the production of inflammatory factors, restoring the level of intestinal tight junction protein and protecting jejunal intestinal barrier function in heat-stressed broilers.

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.

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.

Chitosan Oligosaccharides Alleviate Heat-Stress-Induced Lipid Metabolism Disorders by Suppressing the Oxidative Stress and Inflammatory Response in the Liver of Broilers

Heat stress has been reported to induce hepatic oxidative stress and alter lipid metabolism and fat deposition in broilers. Chitosan oligosaccharides (COSs), a natural oligosaccharide, has anti-oxidant, anti-inflammatory, and lipid-lowering effects. This study is conducted to evaluate dietary COS supplementation on hepatic anti-oxidant capacity, inflammatory response, and lipid metabolism in heat-stressed broilers. The results indicate that heat-stress-induced poor (p < 0.05) growth performance and higher (p < 0.05) abdominal adiposity are alleviated by COS supplementation. Heat stress increases (p < 0.05) serum AST and ATL activity, serum and liver MDA, TG, TC, and LDL-C levels, and the expression of hepatic IL-1β, IL-6, SREBP-1c, ACC, and FAS, while it decreases (p < 0.05) serum SOD and CAT activity, liver GSH-Px and SOD activity, and the expression of hepatic Nrf2, GPX1, IL-10, MTTP, PPARα, and CPT1. Nevertheless, COS supplementation decreases (p < 0.05) serum AST and ATL activity, serum and liver MDA, TG, TC, and LDL-C levels, and the expression of hepatic IL-1β, IL-6, SREBP-1c, ACC, and FAS, while it increases (p < 0.05) serum SOD and CAT activity, liver GSH-Px activity, and the expression of hepatic Nrf2, CAT, IL-10, LPL, MTTP, PPARα, and CPT1. In conclusion, COS could alleviate heat-stress-induced lipid metabolism disorders by enhancing hepatic anti-oxidant and anti-inflammatory capacity.