Carotenoids, ergosterol and tocopherols in fresh and preserved herbage and their transfer to bovine milk fat and adipose tissues: A review

Abstract

The requirements of cattle for the fat-soluble vitamins A, D and E, their provitamins and some carotenoids have increased under conditions of intensive husbandry with insufficient provision of fresh forage, their cheapest natural source. Moreover, bovine milk fat and adipose tissues participate in the intake of these micronutrients by humans. Four major carotenoids occurring in forage crops are lutein, all-trans-β-carotene, zeaxanthin and epilutein. Fresh forage is their richest source. Losses are significantly higher in hay as compared with silage, particularly if prepared from unwilted herbage. Maize silage is a poor source of carotenoids as compared with ensiled grasses and legumes. Ergosterol contents in forages increase under environmental conditions favourable for the growing of moulds, particularly at higher humidity and lower temperatures. Credible data on changes of ergosterol during herbage preservation, particularly drying and ensiling, have been lacking. Alpha-tocopherol is the most important among eight related compounds marked as vitamin E. It is vulnerable to oxidation and herbage ensiling is thus a safer preservation method than haymaking. As with carotenoids, maize silage is a poor source of α-tocopherol. Overall, information on factors affecting the content of ergosterol and tocopherols in fresh herbage, on changes during forage preservation and on transfer to bovine fats has been much more limited than data for β-carotene.

Ergosterol and polyphenols: Potential biochemical indicators of silage safety

“…As it is can be seen in Table 2, the augmentative tendency of ERG content found in the fresh forage samples of orchardgrass from 2012 to 2013 was related at the higher rainy conditions in the second year, contributing to the occurrence and development of fungi. The ERG increase at high relative humidity and lower temperature was previously corroborated by Kalač [44]. In addition, the high ERG content is related to the delayed harvest date [27] and the higher frequency of rains [45] at the timing of harvest.…”

A mobile system for rearing meat chickens on pasture

“…Information about tocopherol content in fresh forage is not consistent (Kalac 2012). Larsen et al (2012) reported that the concentrations of α-tocopherol in various grasses and legumes vary considerably with plant maturity and, to a lesser extent, with species.…”

Natural antioxidants in milk and dairy products

“…In feed and in foods of plant origin, vitamin E is present in the form of eight chemical compounds, including four tocopherols (α, β, γ, δ) and four tocotrienols (α, β, γ, δ). Milk fat contains only α‐tocopherol which characteristically has the highest antioxidant activity (Akoh and Min ; Kalač ). According to Akoh and Min (), α‐tocopherol demonstrates 100% activity, whereas the biological activity of γ‐ and δ‐tocopherols is 10 and 100 times lower, respectively.…”