A review of the changes in carotenes during ensiling of forages

Abstract

The dietary availability of carotenes to the animal depends in part on the relative proportions of different isomers and these may alter during ensiling. The proportions of the more available ,%carotenes are higher in well preserved silages than in clostridial silages. Under anaerobic conditions only small losses of carotenes occur with acidtreated silages but the provitamins are degraded rapidly in some fodder plants in the presence of both acids and oxygen. The presence of nitrites in silages is considered to increase destruction of carotenes.

Effects of nitrogen fertilizer and harvesting stage on photosynthetic pigments and phytol contents of Italian ryegrass silage

“…b-carotene is an easily decomposable pigment; oxidation, ultraviolet rays and pH are the main factors that affect its decomposition (Bruhn & Oliver 1978;Kala c & McDonald 1981;Park et al 1983). However, the relatively higher pH of the silage in the present study, ranging from 5.1 to 5.9, might have contributed to the extensive preservation of b-carotene during ensiling (Kala c & Kyzlink 1979;Lindqvist et al 2012).…”

“…The contents of CP and carotenoids in grass forages are higher in the early reproductive stage compared with more advanced stages (King et al 2012). As b-carotene is easily oxidized once the plants are harvested, its content in stored forage is lower than that in fresh forage (Bruhn & Oliver 1978;Kala c & McDonald 1981;Park et al 1983). Chlorophyll content also increases with increasing N fertilizer application rate (H ak et al 1993) but gradually decreases with drying after harvesting (Ballet et al 2000).…”

Effect of varying fermentation conditions with ensiling period and inoculum on photosynthetic pigments and phytol content in Italian ryegrass (Lolium multiflorum Lam.) silage

“…Destruction of β-carotene during the ensiling process is suggested as being caused by intrinsic enzyme (lipoxygenase) action in herbage (Kalač & Kyzlink, 1980;Kalač & McDonald, 1981). Exposure to air with acid additives causes considerable destruction of β-carotene during the ensiling process, especially for alfalfa (Kalač & Kyzlink, 1980).…”

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

“…Generally, hay is thus a limited source of available carotenoids in ruminant feeding. Data on carotene changes during forage ensiling up to1980 have been reviewed (Kalač and McDonald 1981). Several results from that period should be mentioned here.…”