Abstract
Although carotenoids generally possess antimicrobial and antioxidant properties, the in vivo synergistic action of carotenoid blends derived from plant-based by-products has not been thoroughly studied. Therefore, the carotenoid characterization and antimicrobial potential of Citrus reticulata extract as well as the impact of this carotenoid-rich extract (CCE) dietary supplementation on the performance, meat quality, and immune-oxidative status of broiler chickens were determined. One hundred and twenty one-day-old hatched chicks (Ross 308) were allocated to two dietary groups, with four replicate pens of 15 birds each. Birds were fed either a basal diet (CON) or the basal diet supplemented with 0.1% CCE (25 mg carotenoid extract included in 1 g of soluble starch) for 42 d. β-Cryptoxanthin, β-Carotene, Zeaxanthin, and Lutein were the prevailing carotenoid compounds in the Citrus reticulata extract. The CCE feed additive exerted inhibitory properties against both Gram-positive (Staphylococcus aureus) and negative (Klebsiella oxytoca, Escherichia coli, and Salmonella typhimurium) bacteria. Both the broiler performance and meat quality did not substantially differ, while the breast muscle malondialdehyde (MDA) concentration tended to decrease (p = 0.070) in the CCE-fed broilers. The inclusion of CCE decreased the alanine aminotransferase and MDA concentration, and the activity of glutathione peroxidase, while the activity of superoxide dismutase was increased in the blood. Catalase and NADPH oxidase 2 relative transcript levels were significantly downregulated in the livers of the CCE-fed broilers. Additionally, Interleukin 1β and tumor necrosis factor (TNF) relative transcript levels were downregulated in the livers of the CCE- fed broilers, while TNF and interferon γ (IFNG) tended to decrease in the spleens and bursa of Fabricius, respectively. The present study provided new insights regarding the beneficial properties of carotenoids contained in Citrus reticulata in broilers’ immune-oxidative status. These promising outcomes could be the basis for further research under field conditions.
Highlights
Antimicrobials experienced their golden era between the 1950s and 1970s, they were later characterized as one of the most important threats to humanity [1]
Without narrowing out the imperative necessity for alternatives to antimicrobials, there is a growing consumer demand for the replacement of synthetic with natural antioxidants since the use of synthetic molecules has been linked with possible toxicity on the liver and carcinogenesis in animal and human studies [4]
Bioactive compounds presented in Citrus (Rutaceae family) may be of high importance in animal nutrition since they exert both antimicrobial and antioxidants properties in vitro [5]
Summary
Antimicrobials experienced their golden era between the 1950s and 1970s, they were later characterized as one of the most important threats to humanity [1]. Thenceforth, researchers are scavenging a natural toolbox of bioactive compounds contained in plants as alternatives to antibiotics to promote growth performance and enhance host health [3]. In this light, a wide variety of essential oils (EOs) derived from oregano (thymol, carvacrol), cinnamon (cinnamaldehyde), garlic, rosemary, citrus, etc. Bioactive compounds presented in Citrus (Rutaceae family) may be of high importance in animal nutrition since they exert both antimicrobial and antioxidants properties in vitro [5]. The competition amongst food and feed for resources increasingly suppresses the availability of various promising compounds rich in bioactive substances in animal nutrition
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