The Effect of Different Levels of Bee Propolis with and without Enzyme Treatment in a Wheat-Based Diet on Growth Performance, Carcass Characteristics, and Immune Response of Broiler Chickens

Background: Wheat is one of the most important food products in human and livestock nutrition, but the use of wheat in poultry diets may have limitations.Wheat contains a significant amount of starch and protein, which are used as the source of energy and protein in poultry diets.However, it should be noted that wheat contains non-starch polysaccharides, such as beta-glucan and arabinoglucan, which can affect the digestion and absorption of nutrients.Non-starch polysaccharides in wheat can have negative effects on poultry performance due to their antinutritional properties.In addition, polysaccharides can interfere with digestive enzymes and reduce their activity, which leads to reduced feed efficiency, reduced growth rate, and poorer performance of poultry.Therefore, reducing the negative effects of non-starch polysaccharides in diets containing wheat through the use of methods, such as the addition of enzymes, processing, or the use of plant oil extracts and antibiotics, has been proven to optimize poultry health and performance.According to the proposed properties of bran, it seems that this substance can moderate the negative effects of non-starch polysaccharides in wheat-based diets.The use of natural additives in poultry diets is growing in the world.These compounds improve the performance of animals and poultry without any adverse or residual effects as growth stimulants.Therefore, many researchers are trying to find natural food additives, such as propolis, for poultry diets to improve health and performance.The beeswax, known as bee glue or propolis in the world, is of Greek origin, and the word propolis is composed of two components, Pro meaning defense and Polis meaning city or hive.However, English is preferred, and Pro Polis means guardian.Propolis is a mixture of different amounts of beeswax and resins collected by bees from plants, especially young flowers and leaves.Bees scrape the protective resin of the bud and flower bud with their jaws and carry it like a pollen seed on their hind legs in a basket.Some saliva and other secretions of bees and wax are mixed while collecting propolis resins.The main composition of propolis varies depending on the location, time of collection, and method of production, including 45-55% resins, 25-35% wax and fatty acids, 10% volatile oil, 2% flower pollen, and the other 2% is organic compounds, vitamins, and minerals, such as silver, sodium, mercury, copper, manganese, iron, calcium, vanadium, and silica.Resins form the bulk of the flavonoids found along with a number of phenols and acids.Propolis contains high levels of flavonoids that have pharmacological and physiological effects.Propolis volatile oils have antimicrobial and antifungal activities Recent research has shown that propolis, due to its unique diversity of constituents (especially polyphenols), not only has antioxidant effects but can also regulate inflammatory pathways, immune system function, intestinal microbiome population, and gastrointestinal permeability.Methods: This experiment was performed using 150 Ross 308 broiler chicks in a completely randomized design with a factorial arrangement (2 levels of the enzyme and 3 levels of propolis) with six treatments, five replicates, and five chicks per replicate.For this purpose, different diets based on wheat were formulated for starter, grower, and finisher periods, and then one of the enzyme and propolis was added to the diet of each group of chickens.The experimental treatments were 1) a control diet based on wheat, 2) a control diet + 500 mg/kg of the enzyme, 3) a control diet + 250 mg/kg of propolis, 4) a control diet + 500 mg/kg of propolis, 5) a control diet + 250