Research Progress on Lycopene in Swine and Poultry Nutrition: An Update

**Background:** Oxidative stress from environmental factors, physiological stages, and mycotoxins threatens livestock productivity and health, driving economic losses. With the EU (2006) and China (2020) banning in-feed antibiotics, there is urgent need for natural, safe alternatives. Lycopene (C₄₀H₅₆), a red carotenoid found in tomatoes, carrots, watermelon, and guava, has the greatest antioxidant potential among carotenoids due to its 11 conjugated double bonds. It scavenges free radicals, exhibits anti-inflammatory, anticancer, antidiabetic, and cardiovascular-protective properties, and is approved as a nutrient/food additive in over 50 countries. This review systematically covers lycopene research in swine and poultry from 2013–2022.

**Methods:** The authors conducted a systematic review of literature from the past decade (2013–2022) on lycopene supplementation in swine and poultry. They summarized findings on production performance, meat and egg quality, antioxidant function, immune function, lipid metabolism, and intestinal physiological functions. The review includes data from studies on sows, finishing pigs, weaned piglets, pig embryos, piglet Sertoli cells, broilers (Arbor Acres, Ross 308, Hubbard), Pekin ducks, laying hens (High Line W36, Lohman LSL, Hy-line Brown, Xinghua breeding hens), Japanese quail, and laying quail.

**Key Results:** In swine, 50 mg/kg lycopene during gestation/lactation improved sow reproductive performance (increased born-alive and weaned piglets, litter birth/weaning weight; decreased born-dead piglets). In finishing pigs, 100–200 mg/kg for 70 days improved meat quality (reduced L* and b* values, elevated a* value, intramuscular fat, crude protein) and muscle fiber type transformation (up-regulated slow-twitch markers, down-regulated fast-twitch). Lycopene at 50 mg/kg for 28 days in weaned piglets increased jejunal villus height and villus height/crypt depth ratio, and elevated digestive enzyme activities (lipase, sucrase, maltase, lactase). In broilers, 10–30 mg/kg for 42 days increased ADG and final body weight while decreasing FCR. Under aflatoxin B₁ challenge, 200–400 mg/kg lycopene for 42 days increased ADG and decreased FCR, reduced hepatic CYP1A1 and CYP2A6 activities, decreased AFB₁-8,9-epoxide-DNA and ROS levels, and improved mitochondrial function (increased complex III and V). Under heat stress, 200–400 mg/kg lycopene linearly increased cumulative feed intake, weight gain, and reduced FCR in Ross 308 broilers. In laying hens, 20 mg/kg lycopene for 84 days increased egg weight, yolk color, yolk lycopene level, and decreased yolk MDA and cholesterol. In Xinghua breeding hens, 40 mg/kg for 35 days increased fertilization rate and hatchability. Antioxidant effects included increased T-AOC, GSH-Px, SOD, CAT activities, decreased MDA levels, and activation of the Keap1/Nrf2 pathway across multiple species. Lipid metabolism effects included decreased serum cholesterol, triglycerides, VLDL, and hepatic FAS and ACC activities, with up-regulation of AMPK-α and down-regulation of SREBP-1, FAS, and ACC mRNA. However, high-dose supplementation (500 mg/kg) negatively affected growth performance in Hubbard broilers (decreased ADFI and ADG in week 1) and reduced immune organ weights.

**Clinical Implications:** Lycopene shows strong potential as a natural, green feed additive to replace in-feed antibiotics in swine and poultry production. Effective dietary doses range from 10–400 mg/kg depending on species and physiological stage. Lycopene improves productivity under stress conditions (heat stress, mycotoxin challenge), enhances meat and egg quality, and can produce lycopene-enriched animal products as functional foods for humans. The review recommends further research to establish optimal dosages for different physiological phases and rearing environments, and to elucidate specific mechanisms of action, particularly through in vitro and ex vivo studies.