Plant Feed Additives as Natural Alternatives to the Use of Synthetic Antioxidant Vitamins on Poultry Performances, Health, and Oxidative Status: A Review of the Literature in the Last 20 Years

Abstract

Plant feed additives (PFA) such as essential oils, extracts, and by-products from plant processing can be included in poultry diets. A total of 39 peer-reviewed articles were selected from the literature published in the last 20 years (2000–2020) comparing PFA antioxidant effects with synthetic antioxidant vitamins (mainly vitamin E) in poultry nutrition. The PFA can be used as an effective nutritional strategy to face poultry’s oxidative stress with positive impact also on their productivity and efficiency. They can partially or completely replace antioxidant synthetic vitamins (the latter administered at doses between 150 and 500 mg/kg) in animal diets, sometimes affecting important physiological functions or expressing synergistic effect with the synthetic antioxidants. It is crucial to take into consideration the issues related to the absorption and the metabolism of these additives and their interaction with gut microbiota. However, some form- and dose-dependent negative effects on growth performances are observed.

Antioxidant Status of Broiler Chickens Fed Diets Supplemented with Vinification By-Products: A Valorization Approach

“…These biomaterials are usually discarded into nearby open fields for biodegradation, thus polluting the environment and water reservoirs in the vicinity [ 7 ]. Numerous studies have highlighted the potential of these by-products for use as plant originated feed additives that are predominantly rich in a broad variety of polyphenols [ 8 , 9 ], especially flavonoids, such as catechins and procyanidins with varying degrees of polymerization [ 10 ]. In this context, there are many studies and research endeavors demonstrating the powerful antioxidant properties of these polyphenols, as pure compounds and/or extracts, and their ability to act as potent free radical scavengers for the improvement of an organism’s oxidative balance [ 8 ].…”

“…Since the use of antibiotics as growth promoters was banned in the EU for poultry production in 2006, several management and nutritional strategies in the poultry industry were proposed in order to maintain high standards of productivity, healthiness, and welfare [ 9 ]. More specifically, in broilers, dietary supplementation with grape pomace appeared to effectively substitute vitamin E, preserving the antioxidant capacity in ileal content, excreta, and muscle tissues [ 8 ].…”

Plant Feed Additives as Natural Alternatives to the Use of Synthetic Antioxidant Vitamins on Livestock Mammals’ Performances, Health, and Oxidative Status: A Review of the Literature in the Last 20 Years

“…In livestock mammals, the impact of PFA on the oxidative status of the animal has been investigated less than in poultry [ 15 ]. Indeed, in the poultry sector, PFAs have been widely studied in comparison with synthetic vitamins in order to assess their antioxidant activity on both animals’ performances [ 16 ] and products traits [ 17 ]. In swine, PFA has been mostly tested as alternatives to antimicrobials rather than as antioxidants, particularly after the ban of in-feed antibiotic use in 2006 [ 18 , 19 , 20 ], whereas in ruminants, PFA (usually essential oils) have been widely investigated as rumen modifiers [ 21 , 22 ].…”

Immune-Related Gene Expression Profiling of Broiler Chickens Fed Diets Supplemented with Vinification Byproducts: A Valorization Approach II

“…These wastes are usually discarded into nearby open fields for biodegradation, polluting the environment and the water reservoirs [ 3 ], while plenty of desirable bioactive compounds are wasted as well [ 4 ]. Numerous studies have highlighted the potential of these byproducts for use as plant-originated feed additives that are primarily rich in a broad diversity of polyphenols [ 5 , 6 ].…”