Vitamin E (VE), also known as anti-fertility vitamins, anti-sterility factors or tocopherols, is a generic term for tocopherols, tocotrienols and derivatives that exhibit more or less the biological activity of d-alpha-tocopherol. . Since Evans and Bishop were discovered and named in 1922, at least eight compounds with vitamin E activity have been found so far, the difference between which is that the number and position of methyl groups on the phenol ring in the molecule are different. Four tocopherols (α, β, γ, δ) and four tocotrienols (α, β, γ, δ) were isolated from plant resources. A large number of experiments have proved that vitamin E has a good application effect on improving the reproductive performance of animals.
1. The mechanism of action of vitamin E
Zhu Suzhen et al (2002) believe that vitamin E has a wide range of biological functions in animals, and its reproductive function is achieved through the antioxidant action of vitamin E [1]. Ren Shanmao et al (2001) also believe that the most obvious mechanism of vitamin E affecting reproductive function is anti-oxidation [2]. Vitamin E is an exogenous chain scission antioxidant. Its hydroxyl group on the 6th carbon atom is easily oxidized, so it has strong reducibility. Its structure is shown in Figure 1. Vitamin E protects biofilms from oxidative degradation, and it can also be involved in the synthesis of PGs indirectly. PGs produce peroxidic groups during metabolism, and vitamin E can bind to them. Chen Dongsheng et al (1997) reported that vitamin E supplementation had no significant effect on the production of peroxidic free radicals in polynuclear cells, but it could significantly reduce the concentration of malondialdehyde in animal serum. Therefore, they believe that vitamin E anti-lipid peroxidation is blocked. Free radical reactions, rather than reducing free radical production, Zhu Suzhen et al. (2000), Kamal-Eldio A et al. (1996) also proposed similar views. Azzi A et al. (2000) believe that vitamin E plays a very important role in animal reproduction and that vitamin E is synergistically achieved through antioxidant and non-antioxidant effects [3], Brigelius-Flohe R et al. , 1999 also got similar results [4]. Song Xiaoyan et al. In 2000, the anti-infertility function was mainly due to the nutritional function of vitamin E, which activated the biophysical function and enhanced the secretion of progesterone, thereby promoting the completion of fertilization.
2 the impact of vitamin E on cattle reproduction
2.1 conception rate
Bovine embryos have been reported to die most on days 6-7 and 10-13 of embryonic development, which is associated with vitamin E deficiency. Therefore, supplementation of vitamin E in the early stage of embryonic development and earlier can reduce embryo death and abortion. The Shen Jitang test showed that the test group cows were intramuscularly injected with 500 mg of vitamin E preparation immediately after insemination, and the control group did not do any treatment. The conception rate of the test group was 86.8%, and the pregnancy rate of the control group was 63.6% [5]. Zhou Wenbin's research showed that the cows in the test group had a 7.09% higher rate than the control group (p%26lt; 0.05). Rong Ruqiang et al. (1997) found that 48 cows in the experimental group had 48 pregnancies after mating, the total conception rate was 92.3%, and the pregnancy rate was 71.6%, while the control group of 52 cows were only 44 after pregnancy. The conception rate was 84.6%, and the conception rate was 54.3% [6]. Zhang Zhaoxi and others also reached similar results.
2.2 The placenta does not ,
Postpartum fetal dressing is a major obstacle to the breeding of dairy cows for a long time. The reasons for the retention of the placenta are many. Some scholars believe that the lack of vitamin E will affect the physiological function of the uterine muscle. This abnormal physiological function causes the placenta to stagnate. Xu Kuiqi et al (1997) found that the rate of placenta in the vitamin E group was 6.25%, and that in the control group was 41.18% [7]. Weiss et al pointed out that a mild deficiency of vitamin E and selenium can increase the incidence of placenta. Harrison and other research found that only the simultaneous application of vitamin E and sun can significantly reduce the incidence of placenta. Li Fei et al. (2000) gave the test group cows intramuscular injection of sodium selenite vitamin E 50 mg/head 60-70 days before the expected date of delivery, and there was no placenta at the time of delivery, compared with 16.67% in the control group [8]. Zhang Zhaoxi et al (2002) found that by adding vitamin E powder and sodium selenite 50g per day to each cow, the test group had a rate of 5%, compared with 15% in the control group [9].
2.3 mastitis
Bovine mastitis infectivity is associated with plasma vitamin E and selenium (Erskine, 1987; Smvith, 1986). The important role of vitamin E in breast health should increase the amount of vitamin E supplement, and the addition of vitamin E to the feed can increase the natural resistance of the breast. The dietary vitamin E requirement for dry and lactating cows as determined by NRC (1988) is 15 IU/kg dry matter intake, equivalent to 150 IU and 300 IU vitamin E per day for dry and lactating cows. Atroshi et al (1986) found that cows with clinical mastitis had lower concentrations of alpha-tocopherol in plasma and milk than healthy cows [10]. Studies have shown that vitamin E 1000 IU is fed daily during the dry period, and vitamin E 500 IU is administered daily during lactation. The incidence of bovine mastitis is lower than that of the control group. Zhou Wenbin and other tests found that injection of selenium and vitamin E 20 days before delivery of cows significantly reduced the incidence of mastitis, which was 19.03% and 96.48% lower than that of the control group [11].
3 vitamin E and sheep breeding
Studies have reported that serum vitamin E levels in ewes can be reduced by about 50% on prenatal 7 days, and will not return to normal levels until 20-30 days after birth. Therefore, some people think that to increase the productivity of lambs can supplement vitamin E. Cline et al. (1974) found that the addition of vitamin E to ram diets can increase ejaculation, semen concentration, sperm motility and improve the conception rate and lambing rate of ewes. Wu Xiuku (1995) used testosterone propionate and vitamin E to treat ram spermatozoa and spermatorrhea symptoms, and achieved good results. Most of the deaths of lambs occur in the first few weeks after birth [17]. A1exander (1983) and Rook (1997) reported that about 50% of lamb deaths occurred within the first 3 days after birth, regardless of the production system. Xu Dechun et al (1997) showed that vitamin E and selenium were added to the test. As a result, the abortion rate of the experimental group was 2.27%, while that of the control group was 9.76%. Thomas et al (1995) used 470 ewes to determine the effect of feeding vitamin E on lamb mortality at about 21 days of late pregnancy [18]. As a result, lambs born to ewes supplemented with vitamin E had a higher rate of stillbirth than unsupplemented vitamins. E's ewes are reduced by 50%. Kott (1998) also got similar results. (Williamson et al., 1996) found that in sheep, the injection of vitamin E into the ewes can increase the vigor of the lamb at birth.
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