## 4 Potential Plant Extracts and Plant By-Products as Alternative Sources of Vitamins in Animal Feeds
### Runinants
#### 4.2.2 Effects on Metabolic Parameters and Oxidative Status in Ruminants  
Some effects of PFA on metabolic and haematological parameters and on antioxidant status have been found in ruminants (Table 4). The dietary supplementation with VitE (225 IU of DL-\(\alpha\)tocopherol acetate once per week) or ethanolic safron petal extract--known for its content of two antioxidant compounds from different chemical families: the carotenoid crocins and the flavonoid kaempferol [76] through a subcutaneous injection (25 mg/kg BW) or oral administration (500 mg/kg BW in a liquid form once per week) decreased the lipid oxidation in lambs kidneys significantly as indicated by the MDA values [70]. The subcutaneous injection decreased MDA values by 30.8%, and oral administration reduced the values by 33.5%. This is consistent with their antioxidant action: carotenoids are, in fact, able to inhibit Fe\({}^{3+}\)/AA induced oxidation, scavenge free radicals, and act as reductants, while the flavonoid kaempferol has been found to exert a moderately high free radical scavenging action [7]. The subcutaneous injection of ethanolic saffron petal extract appeared to significantly increase the GSH-Px activity (by 45.9% on average) in blood in comparison with the control and the VitE treated group. This is in agreement with recent studies that evaluated the effects of crocin, crocetin, and safranal on oxidative stress, demonstrating a reduction in lipid peroxidation (MDA levels) and the increase in the levels of glutathione, and antioxidant enzymes, including GSH-Px in the animal organism [77]. Moreover, a significant reduction in the blood cholesterol levels of lambs receiving either the ethanolic saffron petal extract by injection--an effect already described in the literature [78] or the VitE supplement was observed in comparison with the control group and those fed the ethanolic saffron petal extract orally, indicating that the way of administration of nutrient supplements might play a significant role in their effectiveness. This hypothesis is further supported by the significantly higher MDA content (1.87 vs. 1.42 nmol/dL) in the blood plasma of the lambs given the ethanol saffron petal extract orally in comparison with the injected ones [70]. In fattening lambs, the dietary supplementation with either VitE (6 g/kg DM) or naringin (1.5 or 3 g/kg DM) resulted in a significant reduction in the TBARS values (by 38.1%, 29.4%, and by 45.1%, respectively) in their blood plasma [79]. Moreover, both VitE and naringin reduced (by 25% to 30%) the serum concentrations of triglycerides in fattening lambs when fish oil was incorporated into their diets for 21 days [79]. Similar decreases of plasma lipid MDA (20-40%) were found after the administration of _Andrographis paniculata_ (0.5% DM), turmeric acid (0.5% DM), and VitE (400 mg/kg DM) over four weeks [73]. A similar reduction (by 55%) was also observed after 14 weeks following the administration of _Andrographis paniculata_. Plants rich in polyphenols such as rosemary, grape, grapefruit, and marigold decreased lipid peroxidation in bovine tissues [48], did not affect lipid metabolic parameters (triglycerides, NEFA, and phospholipids) and the activity of the antioxidant enzymes in the liver but caused an increase in the content of plasma conjugated dienes, an effect which needs further investigation [58].