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Effects of micronutrient supplementation on performance and epigenetic status in dairy cows
- M. Gasselin, M. Boutinaud, A. Prézelin, P. Debournoux, M. Fargetton, E. Mariani, J. Zawadzki, H. Kiefer, H. Jammes
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The postpartum period is crucial in dairy cows and is marked by major physiological and metabolic changes that affect milk production, immune response and fertility. Nutrition remains the most important lever for limiting the negative energy balance and its consequences on general health status in highly selected dairy cows. In order to analyze the effect of a commercial micronutrient on intrinsic parameters, performances and the epigenome of dairy cows, 2 groups of 12 Holstein cows were used: 1 fed a standard diet (mainly composed of corn silage, soybean meal and non-mineral supplement) and the other 1 fed the same diet supplemented with the commercial micronutrient (µ-nutrient supplementation) for 4 weeks before calving and 8 weeks thereafter. Milk production and composition, BW, body condition score (BCS), DM intake (DMI) and health (calving score, metritis and mastitis) were recorded over the study period. Milk samples were collected on D15 and D60 post-calving for analyses of casein, Na+ and K+ contents and metalloprotease activity. Milk leukocytes and milk mammary epithelial cells (mMECs) were purified and counted. The viability of mMECs was assessed, together with their activity, through an analysis of gene expression. At the same time points, peripheral blood mononuclear cells (PBMCs) were purified and counted. Using genomic DNA extracted from PBMCs, mMECs and milk leukocytes, we assessed global DNA methylation (Me-CCGG) to evaluate the epigenetic imprinting associated with the µ-nutrient-supplemented diet. The µ-nutrient supplementation increased BCS and BW without modifying DMI or milk yield and composition. It also improved calving condition, reducing the time interval between calving and first service. Each easily collectable cell type displayed a specific pattern of Me-CCGG with only subtle changes associated with lactation stages in PBMCs. In conclusion, the response to the µ-nutrient supplementation improved the body condition without alteration of global epigenetic status in dairy cows.
13 - In vivo bio-optical properties of phytoplankton pigments
- Edited by Suzanne Roy, Carole A. Llewellyn, Plymouth Marine Laboratory, Einar Skarstad Egeland, Geir Johnsen, Norwegian University of Science and Technology, Trondheim
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- Phytoplankton Pigments
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- 05 March 2012
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- 27 October 2011, pp 496-537
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Summary
Introduction
In this chapter we focus on spectral in vivo bio-optical (absorption, scattering and fluorescence) characteristics of phytoplankton. As such, the importance of measuring in vivo bio-optical properties of a culture, population or mixed community of phytoplankton is that the optical signatures provide us with important taxonomic, phylogenic and eco-physiological information. The optical signature in the PAR region (400–700 nm) of phytoplankton is central to understand the processes affecting the optical properties of the water column, the potential rate of primary production, phytoplankton community structure, and phytoplankton physiology and photo-ecology. This chapter gives important bio-optical information for interpretation of data from remote sensing and in situ monitoring of phytoplankton blooms (Chapter 14, this volume) and as an aid to study photo-acclimation processes (Chapter 11).
Light, or more precisely, a flux of photons (quanta) hitting a living phytoplankton cell can either be absorbed, scattered, transmitted, emitted as fluorescence/heat or induce photochemistry. The absorption spectrum (PAR) of phytoplankton is a composite signature of cellular photosynthetic and photoprotective pigments, with some contribution from intermediary electron transport components (e.g. flavins, quinines and cytochromes). The nature of the pigmentation varies significantly among phytoplankton groups and with environmental conditions.