Study on the Use of Lutein in Animal Feeding?

Lutein is a carotenoid that is widely found in nature. It is a bright-colored pigment with strong coloring power. It is the main component of plant pigments in vegetables, fruits, flowers, corn, etc. (Krinsky et al., 2005). Lutein was first discovered in carrots at the beginning of the 19th century. Research has now found that it is abundant in many plants, with a high content in marigolds. Humans and animals cannot synthesize lutein and can only obtain it from food or feed. The lutein molecule has 10 conjugated double bonds, giving it strong free radical scavenging ability (Zhang Wei et al., 2012). As research continues, it has been found that lutein has a variety of biological functions, such as enhancing the body's immune function, improving the body's antioxidant capacity, reducing the occurrence and development of cancer, reducing the incidence of cardiovascular disease, and protecting vision. It plays a unique role in these areas (Vishwanathan et al., 2009; Schweigert et al., 2011). Because lutein is safe and non-toxic, and has strong biological functions such as antioxidant properties, it has been approved for addition to a wide range of foods and feeds, and its application fields are gradually expanding.

1 Biological functions of lutein

1. 1 Effect of lutein on the immune function of the body

The immunomodulatory activity of carotenoids has been widely recognized. Since the discovery that lutein has the effect of regulating the immune response of the body, research has been carried out on the effect of lutein on humoral and cellular immunity. It was found that it has a regulatory effect on both humoral and cellular immunity. The results of the study found that adding lutein to the feed of mice can promote antigen-induced lymphocyte proliferation responses and also enhance the antibody response of splenocytes to T cell antigens (Chew et al., 2004). The results of the experiment showed that lutein supplementation in cats and dogs promoted the proliferative response of ConA- and PWM-stimulated peripheral blood lymphocytes in cats and ConA-, PHA- and PWM-stimulated peripheral blood lymphocytes in dogs. The effect of the supplement is dose-dependent. Lutein also significantly enhances the delayed-type hypersensitivity response. The proportion of CD4+ T cells and CD21+ B cells in the peripheral blood of cats increases, while the proportion of CD4+, CD5+, CD8+ T cells and MHC II+ cells in the peripheral blood of dogs increases. The increased proportion of CD5+ T cells and CD4+ Th cells has a promoting effect on the proliferative capacity of lymphocytes. In addition, the expression of cell surface molecules such as IL-2 and MHC II also has an effect on antigen-stimulated lymphocyte proliferation.

After 12 weeks of lutein supplementation, there was no significant change in the blood levels of IgM and IgG. However, after two immunizations with a polyvalent vaccine, a significant increase in IgG concentration was found, indicating that lutein can enhance the body's ability to produce antibodies against specific antigens (Kim et al., 2000). After mice were orally administered a certain dose of lutein for 45 days, the reactivity of delayed-type hypersensitivity and the number of antibody-producing cells and the serum hemolytic factor were significantly increased, but there was no significant effect on the body weight, spleen index or thymus index of the mice, indicating that lutein can enhance the cellular and humoral immune capacities of mice (Zhang Jing et al., 2007).

In addition, lutein can increase the level of humoral immunity by increasing Th-2 cells, significantly increase the antibody titer of laying hens against infectious bronchitis virus (IBV), effectively prevent the peroxidation damage caused by free radicals to poultry embryos, and increase the serum antioxidant level of young chicks (Bedecarrats et al., 2006). The lutein content in eggs is positively correlated with the lymphocyte synthesis capacity and the level of cellular immunity in the offspring. In female quails and their offspring, lutein supplementation in the diet had no effect on the blood IgG levels of the female quails, but significantly increased the level of yolk IgG. The blood IgG levels of the offspring were positively correlated with the amount of lutein added (Ahren et al., 2010).

1. 2 The antioxidant function of lutein

The production of excessive free radicals has a damaging effect on the body. Eliminating excessive free radicals in the body can prevent related diseases caused by this, such as atherosclerosis, cataracts, cancer, cardiovascular disease, and Alzheimer's disease. Since the lutein molecule has one more conjugated double bond than most carotenoid molecules and a hydroxyl group on the terminal group, its antioxidant function is stronger. Its antioxidant effect is achieved by scavenging free radicals, quenching singlet oxygen and reducing the activity of photosensitizers. Lutein was fed to guinea pigs to determine its distribution in guinea pig tissues. The results showed that the lutein content in each tissue, from highest to lowest, was liver, spleen, lung, kidney, plasma, and eye. Lutein was almost undetectable in white adipose tissue. It is speculated that the lutein in tissues such as the lungs is related to the antioxidant effects of the tissue (Michael et al., 2008). In vitro studies have found that lutein can inhibit the DNA oxidative damage caused by metal iron ions and H2O2 to liver cells, and its antioxidant effect is better than that of natural carotene (Bhattacharyya et al., 2010).

Animal test results show that after 40 days of feeding a liver cancer model mouse with 70 mg/kg body weight per day, not only was oxidative DNA damage to liver cells significantly inhibited, but the development of liver cancer was also slowed down. The amount of lutein deposited in the liver is inversely proportional to the degree of oxidative damage to the liver (Moreno et al., 2007). Cisplatin causes the body to produce free radicals, increases oxidative stress in kidney tissue, and causes apoptosis by forming DNA adducts, which cause cells to remain in the G2 phase of the cell cycle. In vitro cell test results have found that lutein has a significant preventive effect on the DNA damage caused by cisplatin in human hepatoma cell lines (HepG2) (Serpeloni et al., 2012). Zhang Huizhu et al. (2012) used a mouse model to confirm that lutein pretreatment can reduce the toxic effects of cisplatin on the liver and kidneys.

1. 3    Prevention of tumors and cancer

Peto et al. (1981) first reported that carotenoids may reduce the incidence of human cancer. Subsequent research results have shown that lutein has a preventive effect on skin cancer, rectal cancer, breast cancer and other cancers. A high intake of carotenoids in fruits and vegetables can reduce the incidence of chronic cancers such as lung cancer, breast cancer and prostate cancer. Toniolo et al. (2001) found that the incidence of breast cancer is closely related to lutein intake, and that the incidence of breast cancer in the high-dose lutein intake group is 2.08–2.21 times lower than that in the low-dose intake group. Chew et al. (2004) believe that lutein and zeaxanthin have unique functions in enhancing immune function, preventing age-related macular degeneration and reducing the incidence of cancer. Research has found that feeding mice a diet high in lutein slows the growth of transplantable breast cancer cells in the body and enhances the proliferative effect of lymphocytes.

Tumor growth may be related to lipid peroxidation in cells. In vitro test results show that lutein can inhibit the auto-oxidation of cell lipids and prevent cell damage caused by oxidation, and its effect is better than that of β-carotene (Gaziano et al., 1995). Animal test results show that the intake of lutein is inversely proportional to the incidence of pre-invasive breast cancer, so lutein is a breast cancer inhibitor (Shim et al., 2012). If people eat spinach and carrots more than twice a week, they can reduce the risk of breast cancer. Due to its immunomodulatory and antioxidant activities, lutein can inhibit tumor angiogenesis and cell proliferation. It can also induce the differentiation potential of tumor cells by taking advantage of their low or undifferentiated characteristics, promoting tumor cell differentiation and reducing their malignancy. However, lutein's effect on preventing cancer may be organ-specific, and further research is needed to make significant progress (Martin et al., 2000).

1. 4 Other functions

Lutein's antioxidant, lipoxygenase inhibitory and anti-inflammatory functions can reduce the erythema, aging and skin burn caused by UV exposure. Research results show that taking a certain amount of lutein (3 mg/d) has a protective effect against ultraviolet rays. Compared with the control group, the amount of ROS in the body is significantly reduced (P <0.05) (Morganti et al., 2002). In animal experiments, lutein can prevent the negative effects of UV light on mouse skin, reduce the acute inflammatory response, and lower blood lysine levels (Gonzalez et al., 2003).

Epidemiological studies and animal experiments have shown that increased lutein intake can prevent atherosclerosis, and that dietary lutein intake and lutein levels in the blood or adipose tissue are negatively correlated with the occurrence of cardiovascular disease. Lutein can reduce the mean arterial pressure, systolic pressure and diastolic pressure of rats with hypertension induced by N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME), relieve cardiac and renal hypertrophy, reduce plasma lipid peroxidation, increase plasma nitrite and reduced glutathione concentrations, When the feeding amount reaches 2 mg/kg body weight, it has a significant effect on preventing L-NAME-induced heart rate reduction, indicating that lutein has significant antihypertensive and antioxidant effects (Sung et al., 2013). In addition, lutein also has a certain preventive effect on diabetes (Sugiura et al., 2008).

2 Application research on feed supplementation

At present, the majority of research on lutein feed supplementation is on its use as a natural coloring agent for coloring poultry products and aquatic products (Zhou Limei et al., 2003). Ding Xiaofeng et al. (2010) added carotenoids and lutein to the diet of yellow catfish, measured the serum levels of carotenoids and lutein, and the effect of the addition on the tyrosinase activity in the blood serum of yellow catfish, to evaluate the effect on the skin pigmentation of yellow catfish. The results showed that yellow catfish selectively deposits carotenoids and lutein, and the addition of lutein and other pigments to the feed has a significant effect on the body color of yellow catfish. The coloring effect of lutein is related to its form.

Common lutein (mainly lutein) has a better coloring effect on hybrid catfish than converted lutein (mainly zeaxanthin). After common lutein is coated, the coloring effect is even better, and the same coloring effect can be achieved by reducing the amount added by 50% (Shi Shaoyi et al., 2010). In addition, lutein is widely used as a natural feed additive in poultry products, such as egg yolks, skin and shin coloring (Huang Xiaochun et al., 2010). The mixed application of lutein from different sources and the development of compound natural lutein additives are also a new direction for future research (Zhou Liangjuan et al., 2003). Toxicological safety evaluation has confirmed that lutein is safe and non-toxic, and can be developed and used as a raw material for health foods and as a food additive (Zheng Ying et al., 2011).

3 Prospects

Functional feed is a new direction of research and development in the feed industry, with the aim of improving animal health. Microecological preparations, enzyme preparations, traditional Chinese medicine extracts, yolk antibodies, etc., are increasingly being used as functional feed additives (Li Zhu, 2006). With the implementation of the ban on the use of synthetic colour feed additives in the production of Grade A green food, natural plant pigments have become the new target of research. Lutein, as a kind of natural plant pigment, has a variety of biological functions. With the continuous deepening of research on it and the continuous development of modern biotechnology and other technologies, it will be widely used in animal production, food processing and the pharmaceutical industry. In particular, it is expected to become a new kind of functional feed additive and will gradually be added to the feed for use. It has broad application prospects.

References

[1] Ding Xiaofeng, Ye Yuantu, Jiang Rong, et al. Effect of feed pigments on the content of skin carotenoids and flavins and the activity of tyrosinase in yellow croakers [J]. Journal of Fisheries of China, 2010, 34(11): 1728–1735.

[2] Shi Shao-yi, Li Xiao-qin, Leng Xiang-jun, et al. Effect of adding different forms of lutein to the feed on the body color of hybrid catfish [J]. Journal of Shanghai Ocean University, 2010, 19(2): 196-200.

[3] Zhang Jing, Tang Fen-fang, Zhang Tian-meng, et al. Study on the effect of lutein on immune function in mice [J] . Food Industry Science and Technology, 2007 , 28(12) :  193~195.

[4] Zhang Wei, Tong Nian-ting, Yin Li-li, et al. Experimental research progress on the role and mechanism of lutein in ophthalmic diseases [J] . Journal of Shanghai Jiaotong University (Medical Sciences), 2012, 32 (2): 231–234.

[5] Zhang Huizhu, Liu Shumei, Bai Jing, et al. Effect of lutein pretreatment on the ultrastructure of rat liver damaged by cisplatin [J]. Tianjin Medical, 2012, 40 (5): 490–492.

[6] A-Lun, Dong Xiao-Fang, Tong Jian-Ming, et al. The effect of lutein on the reproductive performance of quails and the transfer of maternal IgG to offspring [J]. Journal of Animal Science and Veterinary Medicine, 2010, 41(3): 371-376.

[7] Zhou Li-Mei, Zhou Guang-Hong. Carotenoids and product coloring [J].  Chinese Animal Husbandry and Veterinary Medicine, 2003, 30(3): 30-31.

[8] Zhou Liangjuan, Ji Cheng, Li Yuxin, et al. Study on the coloring effect of several natural lutein on three yellow broilers [J]. Feed Industry, 2003, 24(4): 36-40.

[9] Zheng Ying, Ma Aiguo. Research progress on the safety and biological function of lutein [J]. Journal of Qingdao University School of Medicine, 2011, 47(4): 283-285.

[10] Li Zhu. Functional feed—nutritional trends of lutein, chromium and other nutrients for animal health and production performance [J]. Feed Wide Angle, 2006, 11: 29~31.

[11] Huang Xiaochun, Wu Lingying, Qiu Yinsheng, et al. Comparison of the bioavailability of lutein and lutein esters in laying hens [J]. Grain and Feed Industry, 2010, 10: 40~41.

[12]Bedecarrats  G Y ,  Lesson S.  Dietary lutein influences immune re- sponse in laying hens[J] .  J Appl Poult Res ,  2006 ,  15(2) :  183 ~ 189.

[13]Bhattacharyya S ,  Datta S ,  Mallick  B ,  et  al.   Lutein  content  and in vitro antioxidant activity of different cultivars of Indian mari- gold  flower  (Tagetes patola  L. )   extracts [J] .  J  Agric  Food Chem ,  2010 ,  58(14) :  8259~8264.

[14]Chew B P ,  Park J S.   Carotenoid action on the immune response[J] . Nutr ,  2004 ,  134(1) :  257S~261S.

[15]Gaziano J  M ,   Manson  J  E ,   Buring  J  E ,   et  al.    A  p rosp ective study of consumption of carotenoids in fruits and vegetables and decreased cardiovascular mortality in the elderly[J] .  Ann Epide- miol ,  1995 ,  5(4) :  255~260.

[16]Gonzalez S ,  Astner  S ,  An  W ,  et  al.   Dietary  lutein/zeaxanthin decreases ultraviolet  B-induced  epidermal  hyp erp roliferation  and acute inflammation in hairless mice[J] .  J Invest Dermatol ,  2003 , 121(2) :  399~405.

[17]Kim  H W ,  Chew  B  P ,  Wong  T  S ,  et al.   Dietary lutein  stimu- lates immune response in the canine[J] . Veterinary Immunology and Immunopathology ,  2000 ,  74(3~4) :  315~327.

[18]Krinsky N I ,  Johnson E J .   Carotenoid  actions and their relation to health and disease[J] . Mol Aspects Med ,  2005 ,  26(6) :  459 ~ 516.

[19]Martin K R ,  Wu D ,  Meydani  M.   The  effect  of  carotenoids  on the exp ression of cell  surface  adhesion molecules  and  binding  of monocytes to human aortic endothelial cells[J] .  Atherosclerosis ,  2000 ,  150(2) :  265~274.

[20]Michael W S , Somdutta S R , Shyamali M ,  et al.  Identification of lutein ,  a dietary antioxidant carotenoid in guinea pig tissues[J] .  Biochemical  and  Biophysical  Research  Communications ,  2008 ,  374(2) :  378~381.

[21]Moreno F S ,  Toledo  L  P ,  de  Conti  A ,   et  al.   Lutein  presents supp ressing but not blocking chemop reventive activity during di- ethylnitrosamine-induced  hepatoeareinogenesis  and  this  involves inhibition of  DNA  damage[J] .  Chem  Biol  Interactions ,   2007 ,  168(3) :  221~228.

[22]Morganti P ,  Bruno C ,  Guarneri F ,  et al.   Role of topical and nu- tritional supplements  to  modify  the  oxidative  stress [J] .    Int  J Cosmet Sci ,  2002 ,  24(6) :  331~339.

[23]Peto R ,  Doll  R ,   Buckley J  D ,  et  al.   Can  dietary  beta-carotene materially   reduce   human    cancer   rates  [ J ] .    Nature ,    1981 ,  290(5803) :  201~208.

[24]Schweigert F  J ,  Reimann J .   Micronutrients  and  their  relevance for the eye———Function of lutein ,  zeaxanthin and omega-3fatty acids[J] . Klin Monbl Augenheilkd ,  2011 ,  228(6) :  537~543.

[25]Serpeloni J M ,  Barcelos G R ,  Friedmann Angeli J P ,  et al.  Diet- ary  carotenoid  lutein  protects  against  DNA  damage  and  altera- tions of the  redox  status  induced  b y  cisplatin  in  human  derived HepG2cells[J] .  Toxicology inVitro ,  2012 ,  26(2) :  288~294.

[26]Shim E ,  Yeum K J ,  Tang G ,  et al.   Retinoids ,  carotenoids ,  and tocopherols in breast  adipose  tissue  and  serum  of  benign  breast disease  and  breast  cancer  patients [J] .  Nutr  Cancer ,   2012 ,  64(7) :  956~963.

[27]Sugiura M ,  Nakamura M ,  Ogawa K ,  et al.   Associations  of  ser- um carotenoid  concentrations  with  the  metabolic  syndrome :  In- teraction with smoking[J] .  British Journal of Nutrition ,  2008 ,  100(6) :  1297~1306.

[28]Sung J  H ,  Jo Y S ,  Kim S J ,  et al.  Effect of lutein on L-NAME- induced  hyp ertensive   rats [J] .   Korean  J   Physiol   Pharmacol ,  2013 ,  17(4) :  339~345.

[29]Toniolo P ,  Van  Kappel  A  L ,   Akhmedkhanov A ,  et  al.   Serum carotenoids  and  breast  cancer [J] .    Am  J   Epidemiol ,   2001 ,  153(12) :  1142~1147.

[30]Vishwanathan R ,  Goodro E F ,  Wooten B R ,  et al.   Consumption of 2and 4egg yolks/d for 5wk increases macular pigment in ol- der adults with low macular pigment taking cholesterol-lowering statins[J] . Am J Clin Nutr ,  2009 ,  90(5) :  1272~1279.