Effects of mountain grassland maturity stage and grazing management on carotenoids in sward and cow's milk

Abstract

-Carotenoids are involved in the sensorial and nutritional values of dairy products. In grazing systems, both herbage maturity stage and grazing management may affect the amount of carotenoid ingested, thus these factors may affect carotenoid concentrations in milk. Two homogenous plots of mountain grassland (1.4 and 2.0 ha) were grazed during two cycles of growth by 6 dairy cows in mid lactation, in strip (SG) and rotational grazing (RG), respectively. We monitored the changes in carotenoid concentrations in sward and milk, measured by HPLC twice a week. Seven carotenoids were identified in the sward: violaxanthin, antheraxanthin, epilutein, lutein, zeaxanthin, ß-carotene and 13-cis ß-carotene. Forage quality decreased throughout the course of the first growth stage, but carotenoid concentration in sward did not significantly change. In early regrowth, forage quality was high and the concentration of ß-carotene and xanthophylls also tended to be higher. Carotenoid concentrations in sward were not affected by grazing management, averaging 350 µg per g DM. The carotenoids identified in milk were β-carotene (75%) and lutein (25%). A significant decrease in ß-carotene concentration in milk was observed throughout the course of the first growth stage, from 5.37 to 3.87 µg per g fat, whereas it increased to 4.91 µg per g fat in early regrowth. β-carotene concentration in milk was not affected by grazing management, averaging 4.72 and 5.03 µg per g fat for RG and SG, respectively. However, lutein concentration was slightly lower for RG than for SG, averaging 1.39 and 1.74 µg per g fat, respectively. It is concluded that carotenoids in milk were only slightly affected by herbage maturity stage, and to a lesser extent by grazing management. caroténoïdes du lait pourraient dépendre du stade de l'herbe et du mode de pâturage, qui conditionnent la quantité et la qualité de l'ingéré. Pour valider cette hypothèse, deux prairies naturelles de montagne homogènes, de 1,4 et 2,0 ha, ont été exploitées par 6 vaches en milieu de lactation, en pâturage tournant rapide (SG) et lent (RG), respectivement, pendant deux cycles de végétation. Nous avons suivi l'évolution des teneurs en caroténoides de l'herbe et du lait, déterminées par HPLC sur deux prélèvements par semaines. Dans l'herbe, sept caroténoïdes ont été identifiés : violaxanthine, anthéraxanthine, épilutéine, lutéine, zéaxanthine, ß-carotène et 13-cis ß-carotène. Au cours du premier cycle de végétation, la valeur nutritive de l'herbe a fortement diminué, mais sa teneur en caroténoïdes n'a pas été significativement modifiée. Les teneurs en ß-carotène et xanthophylles et la valeur nutritive de l'herbe étaient les plus élevées au début du deuxième cycle. La concentration en caroténoïdes de l'herbe n'a pas été affectée par le mode de pâturage, et était en moyenne de 350 µg par g MS. Dans le lait, les caroténoïdes identifiés ont été le ß-carotène (75 %) et la lutéine (25 %). La concentration en ß-carotène dans le lait a diminué significativement de 5,37 à 3,87 µg par g M...

Nutrient composition and <i>in vitro</i> digestion parameters of Jerusalem artichoke (<i>Helianthus tuberosus</i> L.) herbage at different maturity stages in horse and ruminant

“…The zeaxanthin content in the present study was similar with the values indicated for natural mountain grassland (in mid-June) (Calderón et al, 2006). In the present study, the β-carotene concentrations of Jerusalem artichoke herbage were satisfactory for vegetative, early flowering and full flowering stages, but its concentration was low at early seeding stage (Calderón et al, 2006). The high total carotenoid content of Jerusalem artichoke herbage at full flowering may be related to the yellow coloured flowers of this plant.…”

“…The lutein content of Jerusalem artichoke in the current study was slightly lower than that indicated for different forage by previous researchers (Calderón et al, 2006). The zeaxanthin content in the present study was similar with the values indicated for natural mountain grassland (in mid-June) (Calderón et al, 2006).…”

“…The lutein content of Jerusalem artichoke in the current study was slightly lower than that indicated for different forage by previous researchers (Calderón et al, 2006). The zeaxanthin content in the present study was similar with the values indicated for natural mountain grassland (in mid-June) (Calderón et al, 2006). In the present study, the β-carotene concentrations of Jerusalem artichoke herbage were satisfactory for vegetative, early flowering and full flowering stages, but its concentration was low at early seeding stage (Calderón et al, 2006).…”

Development of a method to determine carotenoid composition of fresh forages

“…The concentrations of b-carotene and lutein found in our green forage samples are comparable with those reported by Reynoso et al (2004) in two forages (Digitaria decumbens and Cynodon dactylon) present in two tropical regions of Mexico. These carotenoids have also been detected in alfalfa by Livingston et al (1968) and in natural grassland (mainly Poaceae and dicotyledon species) by Calderon et al (2006). It has been show that the concentration of each carotenoid in forages Table 2.…”

Simultaneous analysis of carotenoids and tocopherols in botanical species using one step solid–liquid extraction followed by high performance liquid chromatography

“…Second, some critical isomers such as neoxanthin/violaxanthin, lutein/zeaxanthin, b-/9-Z-b/13-Z-b-carotenes, and b-and ctocopherols are not well resolved under the conditions reported (Table 1). Third, only major carotenoids (b-carotene and lutein) are often quantified probably due to the difficulties in the resolution of a high number of isomer compounds present in very low concentration in plants (Calderón et al, 2006;Cardinault et al, 2008).…”