Extended abstract

Introduction and Objective: In today's industrial poultry farming, especially broiler chickens, there are various types of stress that affect the health and performance of poultry and cause significant economic losses. Stressors can often lead to oxidative stress, which ultimately leads to reduced performance and increased mortality in broiler chickens. In addition, stress can disrupt the immune system and the balance of the intestinal bacterial population, thereby increasing mortality and reducing production performance in broiler chickens. Therefore, it has been suggested that the use of antioxidant compounds is likely to be effective in reducing the problems caused by stressors in order to maintain the health and production performance of the flock in broiler farms. Among the most important antioxidant compounds in nutrition are polyphenolic compounds that are found in plant-derived materials. Due to their high antioxidant and anti-inflammatory activity, polyphenolic compounds are well-known compounds that have been shown to cause positive changes in animal health and performance by improving the body's antioxidant status.

Phloretin, extracted from various fruits (including apples, pears, and peaches), leaves, trees, and vegetables, is a bioactive flavonoid that has many biological activities, including antioxidant, hypoglycemic, and protective. The antioxidant, immune-enhancing, and anticancer effects of phloretin have been reported in human studies. In the food, pharmaceutical, and health industries, phloretin has been proven to be a novel, natural, and highly effective antioxidant. However, there is very little information about the effects of phloretin on the performance and changes of antioxidant and immunity in broiler chickens. Therefore, the present study was designed to evaluate phloretin on growth performance, antioxidant and immune status, and some biochemical parameters of broiler chickens.

Materials and methods:

A total of 300 one-day-old male broiler chicks (44 ± 1.2 g) of the commercial Ross strain (308) were distributed in 4 experimental treatments (5 replicates and 15 chicks per experimental unit). The experimental treatments included: 1- Control group (fed with basal diet and drinking water without any additives), 2- F-100 group (fed with basal diet + 100 mg phloretin per liter of drinking water), 3- F-200 group (fed with basal diet + 200 mg phloretin per liter of drinking water), and 4- F-300 group (fed with basal diet + 300 mg phloretin per liter of drinking water). The phloretin used in this experiment was a product of China (Shaanxi Undersun Biomedtech Co., Ltd) in the form of a white powder with a purity of 99% and soluble in water. The light, temperature, ventilation, humidity and hygiene program were set for all experimental treatments in the same way and according to the recommendations of the Ross 308 strain for different time periods. The amount of feed consumed and the body weight of the birds of each experimental unit were measured at the age of 42 days and the performance indices (feed intake, weight gain and feed conversion ratio) were calculated for the age of one to 42 days. At the age of 42 days, two broiler chickens from each replicate with a weight close to the average of that replicate were selected and the wing vein was used with special blood sampling syringes and a 2 ml sample was used to prepare serum for measuring the biochemical indices of the blood. To determine the bacterial population of the ileum, the selected birds were slaughtered after blood sampling and about two grams of the ileum contents were emptied into sterile microtubes and stored at -20°C until the time of microbial cultivation for the study of the population of Escherichia coli and Lactobacillus. Serum antioxidant parameters including glutathione peroxidase and superoxide dismutase enzymes were measured using Nonand Salamat brand kits. To determine the serum malondialdehyde concentration, the light absorption in the samples was determined by colorimetric method using a device. Serum enzymes including aspartate aminotransferase and alanine aminotransferase were measured using Padco brand kits. Serum immunoglobulins G and M levels were measured using kits from the company (DIASORIN S.P.A. Italia). Serum lipid parameters triglyceride and cholesterol were measured using a quantitative detection kit from Pars Azmoun Company. The collected data were statistically analyzed using the GLM procedure of SAS software version 1.9 (SAS.2003) in a completely randomized design. Data on losses were transformed using the √(X+1) square root transformation before analysis. Duncan's multiple range test was used to compare means at a significance level of 5%. Orthogonal independent comparisons were also used to determine linear and quadratic effects of different levels of phloretin.

Results and discussion:

Phloretin inclusion significantly increased weight gain and significantly decreased feed conversion ratio (P<0.05), but had no significant effect on feed intake and mortality in the entire period (P>0.05). The best performance compared to other treatments was related to the 200 mg/kg phloretin treatment. In addition, phloretin supplementation significantly increased antioxidant capacity (increased activity of glutathione peroxidase and superoxide dismutase enzymes and decreased malondialdehyde concentration), increased triglycerides, and decreased serum levels of aspartate aminotransferase and alanine aminotransferase enzymes (P<0.05). Phloretin administration also significantly increased serum levels of immunoglobulins G and M (P<0.05). A significant increase in the bacterial population of Lactobacillus and a significant decrease in the bacterial population of E. coli were also observed due to the use of phloretin (P<0.05).

Conclusion:

In general, the results of this study showed that the use of phloretin at a level of 300mg/kg in the diet of broiler chickens is likely to improve growth performance, increase antioxidant capacity