| چکیده انگلیسی مقاله |
Introduction:
Modern broilers have been intensively selected for improved feed efficiency coupled with high growth rates has led to significant welfare problems in commercial broiler chickens and renders them particularly susceptible to various types of stress which would induce oxidative stress. A variety of oxidative stress models have been established and applied to better understanding and revealing the underlying mechanisms involved in oxidative damage on domestic animals and the action models of cellular antioxidant defense, as well as to evaluate the effectiveness of different antioxidants. These models can be generally divided into environment-induced oxidative stress (e. g., cold stress), nutritional oxidative distress (e. g., oxidized fats and oils, and mycotoxin-contaminated feed;), and chemical-inducing oxidative stress (e. g., hydrogen peroxide, and dexamethasone.
Chlorogenic acid (CGA), also known as 5-O-caffeoylquinic acid, is an ester of caffeic acid with quinic acid, which is naturally found in a variety of different plant species and possesses multiple biological functions, such as antioxidant, antimicrobial, antiviral, anti-inflammatory, antidiabetic, and anticancer activities. The special phenolic structure endows CGA with good free radical scavenging activities, and it could beneficially scavenge different free radicals and effectively inhibit cellular lipid peroxidation and beneficially regulate cellular membrane stability. The experimental and clinical evidence has confirmed CGA in vivo and in vitro antioxidant effects through its direct antioxidant activity and/or regulation on signal transduction pathways involved in cellular antioxidant defense. The antioxidant characteristic of CGA enables its usage as a promising and green antioxidant in animal feed. It has been shown that dietary supplementation with CGA could improve growth performance and intestinal mucosal antioxidant capacity in piglets by elevating antioxidant enzyme activities, preventing lipid peroxidation, and activating antioxidant signaling pathways. In broilers, dietary CGA supplementation has been reported to enhance growth performance, alleviate inflammatory response, prevent gut damage, improve intestinal mucosal barrier function, and ameliorate oxidative injury in broilers challenged with coccidiac or Clostridium perfringens. However, little was known about the antioxidant function of CGA in broilers. Therefore, the current research was designed with the aim of evaluating the chlorogenic acid on the growth performance, antioxidant and immune status, and some biochemical parameters of broiler chickens.
Materials and methods: A total 300 one-day-old chickens (Ross, 308) were done in the form of a completely randomized design with 4 treatments and 5 replications (15 chickens in each replication). Experimental treatments include: 1- control group (fed with basic diet), 2- group CGA-500 (fed with basic diet + 500 mg/kg chlorogenic acid), 3- group CGA-1000 (fed with diet base + 1000 mg/kg of chlorogenic acid), and 4- group CGA-1500 (fed with base diet + 1500 mg/kg of chlorogenic acid). Growth performance parameters including feed intake, weight gain and feed conversion ratio were calculated for the total period. On the last day of the experiment (42 d), two birds were randomly selected from each cage and after bleeding from the wing vein, killed and liver sampled. The mortalities were collected as soon as they were observed and after weighing to correct the feed conversion ratio. The concentration of triglyceride, cholesterol, LDL, and HDL, as well as serum antioxidant parameters including the level of malondialdehyde and the activity of antioxidant enzymes including glutathione peroxidase, and superoxide dismutase. Also, the hepatic pro-Inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) were determined. In addition, serum parameters including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and Immunoglobulin G (IgG), and Immunoglobulin M (IgM), were also measured.
Results and discussion: The results showed that inclusion of chlorogenic acid caused a significant increase in feed intake and weight gain and a significant decrease in feed conversion ratio and total mortality (P<0.05). The best performance compared to other treatments was related to the treatment of 1000 mg/kg of chlorogenic acid. In addition, chlorogenic acid supplementation at the level of 500 and 1000 mg significantly improved the antioxidant capacity (increased activity of glutathione peroxidase enzyme and decreased malondialdehyde) of serum and liver (P<0.05). Also, administration of 500 and 1000 mg of chlorogenic acid significantly reduced serum levels of inflammatory cytokines IL-1β, IL-6 and TNF-α (P<0.05). A decrease in serum levels of aspartate aminotransferase, alanine aminotransferase, triglyceride, cholesterol, LDL, and an increase in HDL and immunoglobulins G and M were also observed in CGA-1000 and CGA-1500 treatments (P<0.05). In general, the results of this research showed that the use of 1000 mg/kg of chlorogenic acid in the diet of chickens may improve growth performance and improve antioxidant and inflammatory indices.
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