The aims of this work were to determine the effect of upland origin on milk composition when comparing similar lowland and upland production system and to highlight the factors responsible for the added value of upland milk from commercial farms. Tanker milk from 55 groups of farms (264 farms in total) in France, Slovakia, and Slovenia was collected twice during the indoor season and 3 times during the outdoor season. The tanker rounds were selected in each country to be balanced according to their origin (lowland or upland) and within upland or lowland groups, according to the forage systems: corn-based or grass-based forage system. At each milk sampling, the production conditions were recorded through on-farm surveys. The milk was analyzed for gross composition, carotenoids, minerals, fatty acids, phenolic compound derivatives, volatile organic compound concentrations, and color. The milk from upland and lowland areas differed in their contents of a few constituents. Upland milk was richer in not identified (n.i.) retention time (Rt) 13,59, 4-methylpentylbenzene, 1-methyl-2-n-hexylbenzene, and β-caryophyllene than lowland milk. These differences could be most likely attributable to the utilization of highly diversified and extensively managed semi-natural grasslands. The higher forbs content of upland pastures could be related as well to the richness in C18:3n-3, CLA cis-9,trans-11, MUFA, and PUFA we observed in upland compared with lowland milk during the outdoor season. In contrast, grazing on lowland pastures rich in grasses gave a yellower milk that was richer in β-carotene. Out of the few compounds showing a significant effect of origin or its interaction, most of the milk constituents were unaffected by the origin at all. However, almost all milk constituents differed according to the forage system and the season, and the differences observed between seasons can be attributed to differences in the cow diet composition.

Plants, insects and microorganisms are the protagonists of the ecosystem services provided by permanent grasslands. All of them emit volatile organic compounds (VOCs) to communicate. The result is a chemical landscape, also called odorscape. To explore this pool of information and enhance our understanding on the process behind the ecosystem services, we trapped volatile compounds on two mountain permanent pastures chosen for their contrasting grazing and fertilisation management. Measurements were made in July over two periods of three consecutive days using solid-phase microextraction (SPME) fibers fixed on sticks. The VOCs adsorbed on the fibers were then analyzed by gas-chromatography-mass spectrometry (GC-MS). We also recorded floristic composition, trapped the pollinator insects and took pictures of the canopy to quantify grassland colors using image analysis. We obtained rich and complex VOC profiles. They contained a total of 67 peaks corresponding to VOCs belonging to various chemical families. Nevertheless, the differences between the two grasslands chemical signatures were less marked than expected, considering their differences in floristic species richness (83 vs. 65 species). Certain compounds however, were specific to one of the two pastures and others were positively (e.g. benzaldehyde) or negatively (e.g. α-pinene) correlated to the presence of pollinators. Measuring the odorscape constitutes a promising tool to better understand a range of services provided by grasslands.

The aim of this work was to study the effect of dairy system and individual cow-related factors on the volatile fingerprint of a large number of individual model cheeses analyzed by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). A total of 1,075 model cheeses were produced using milk samples collected from individual Brown Swiss cows reared in 72 herds located in mountainous areas of Trento province (Italy). The herds belonged to 5 main dairy systems ranging from traditional to modern and the cows presented different daily milk yields (24.6±7.9kg × d(-1)), stages of lactation (199±138 d in milk), and parities (2.7±1.8). The PTR-ToF-MS revealed 619 peaks, of which the 240 most intense were analyzed, and 61 of these were tentatively attributed to relevant volatile organic compounds on the basis of their fragmentation patterns and data from the literature. Principal component analysis was used to convert the multiple responses characterizing the PTR-ToF-MS spectra into 5 synthetic variables representing 62% of the total information. These principal components were related to groups of volatile compounds tentatively attributed to different peaks and used to investigate the relationship of the volatile compound profile obtained by PTR-ToF-MS to animal and farm characteristics. Lactation stage is related to 4 principal components which brought together 52.9% of the total variance and 57.9% of the area of analyzed peaks. In particular, 2 principal components were positively related to peaks tentatively attributed to aldehydes and ketones and negatively related to alcohols, esters, and acids, which displayed a linear increase during lactation. The second principal component was affected by dairy system; it was higher in the modern system in which cows received total mixed rations. The third principal component was positively related to daily milk production. In summary, we report the first application of this innovative, high-throughput technique to study the effects of dairy system and individual animal factors on volatile organic compounds of model cheeses. Individual cheesemaking procedures together with this spectrometric technique open new avenues for genetic selection of dairy species with respect to both milk and cheese quality.

Carotenoids, vitamins and phenolic compounds present in milk contribute to its nutritional value. Their levels widely depend on the composition of ingested grass, but how exactly does the botanical diversity of mountain grassland affect these levels? Changes, over the pasturing season, in carotenoid, tocopherol and polyphenol levels was studied in medium altitude grassland forage with a diversified vegetation (under experimental conditions or on farms with varied pasture practices) and in the milk produced by cows, grazing on this grassland. The following observations were made i) an inverse evolution between the stage of development of forage grass species and carotenoid levels and ii) grassland with a lower botanical diversity used in a more intensive way has higher carotenoid levels but lower polyphenol levels. However, these differences in the nutritional value of forage do not necessarily result in a difference in milk concentration.

The combined effects of lucerne (Medicago sativa L.) extract supplementation and ammonia treatment of rice straw (Oryza sativa, variety Thaibonnet) on the ruminal digestion of cell wall components were investigated in six continuous culture systems using a randomised complete block design. Data were fitted to second-order polynomial models. Untreated rice straw had higher contents of ash-free cell wall residues (CWR; 763 v. 687 g/kg dry matter (DM)) and non-cellulosic sugars (191 v. 166 g/kg DM) than treated rice straw Ammoniation preferentially removed xylose, which resulted in a lower xylose-to-arabinose ratio (5.1 v. 5.8). In absence of lucerne supplementation and ammoniation, degradability coefficients were 0.54, 0.46, 0.58, 0.54, 0.42 and 0.60 for cellulose glucose, xylose, arabinose, galactose, mannose and uronic acids, respectively Both factors had significant effects on the microbial degradation of structural polysaccharides. With lucerne extract at an optimal level, ammonia treatment increased ash-free cell wall degradation by more than 10%. The degradability coefficients were increased by ammoniation without any significant interaction with lucerne extract, except for glucose, whose degradability was mostly influenced by lucerne extract in a curvilinear way. The comparison of regression coefficients in cell wall and CWR models suggested that ammoniation improved the degradabilities of xylose, galactose and mannose by partly solubilising the corresponding hemicelluloses and by improving the susceptibility of the remaining fraction to microbial attack, whereas it increased the degradability of arabinose only by favouring microbial attack.

Several efforts have been done in the last years to trace grass feeding directly in the herbivore products and different methods, based on carotenoid pigments (Priolo et al., 2002; Prache et al., 2003) have been proposed. Some volatile compounds, such as 2,3-octanedione or 3-methylindole (skatole) have been indicated as excellent indicators of pasture diets (Young et al., 1997)...

The development of analytical methods to verify the production system of meat products requires the identification of biomarkers that can trace the product's origin, and secondly the factors that govern the deposition of these markers in animal tissue need to be defined. In this study, 2,3-octanedione, skatole and terpenes were selected as biomarkers, and their deposition was investigated in bull calves reared under three different strategies. All of the animals were reared indoors until approximately 150 days of age. They were suckled twice a day by their mothers, and both calves and cows had free access to cocksfoot hay. Then the first two groups of animals were kept indoors, suckled by their mothers twice a day and received either cocksfoot hay (HL) or freshly cut-green herbage (GL) and a limited quantity of concentrate. The third group of calves (PH) was kept on pasture with their mothers and offered concentrate ad libitum. The pasture supporting the PH animals was highly diversified, containing several terpene-rich plant species, whereas the herbage for the GL animals contained no species known to be aromatic. Perirenal and subcutaneous adipose tissues were analysed for volatile compounds. The perirenal fat was found to be more responsive to the treatment and a more reliable substrate than the subcutaneous adipose tissue. Higher levels of 2,3-octanedione (P < 0.05) were found in PH and GL than in HL fat (6.56, 6.51 and 5.77 area arbitrary units, respectively, in perirenal fat), confirming the ability of this molecule to trace green herbage feeding. Skatole was detected in the perirenal and subcutaneous fat of all the animals. Animals receiving high concentrate level (PH group) presented lower (P < 0.05) skatole values (5.83 area arbitrary units in perirenal fat) than animals receiving low concentrate level (HL and GL groups, 6.23 and 6.71 area arbitrary units, respectively, in perirenal fat). Terpenoids, and especially sesquiterpenes, were found at higher levels and diversities in the PH than in the GL and HL animals. Two monoterpenoids allowed group discrimination considering perirenal or subcutaneous fat without distinction, whereas 11 and 5 sesquiterpenoids from perirenal and subcutaneous fat, respectively, allowed it.

Les mécanismes moléculaires à l’origine des processus biologiques sont gouvernés par les produits de l’expression d’une multitude de gènes dont les stratégies d’étude ont bénéficié d’avances technologiques considérables ces dernières années. En effet, alors que la biologie moléculaire était ciblée sur quelques gènes choisis selon leur fonction biologique dans les processus étudiés, les approches en «omique» permettent aujourd’hui d’étudier simultanément un grand nombre de gènes, protéines ou métabolites sans a priori sur leur fonction biologique. Ces nouvelles technologies peuvent contribuer à une meilleure connaissance de la biologie des herbivores dans une perspective d’élevage durable. Dans les exemples présentés dans cette courte synthèse, il apparaît en effet que ces approches à haut débit peuvent contribuer à améliorer l’efficacité économique des productions notamment par la détection de marqueurs de l’exposition aux mycotoxines et par une meilleure efficacité métabolique et physiologique des herbivores (partage des nutriments entre tissus et organes, différenciation du muscle pour la production de viande, régulation de l’expression des gènes par les nutriments). Les approches en «omique» peuvent aussi contribuer aux autres piliers du développement durable : bien-être animal (par la mise en évidence de marqueurs de stress), protection de l’environnement (par la maîtrise des rejets azotés par les animaux), qualité des produits (par une maîtrise de la composition en acides gras et de la qualité sensorielle des produits laitiers et carnés, et par la recherche biologique de prédicteurs de la tendreté de la viande).

The molecular mechanisms underlying biological processes are governed by the expression of many genes. The methods studying these complex processes have experienced tremendous technological advances over the past few years. Whereas in the past, molecular biology targeted a few genes chosen for their biological function, today, genomics, proteomics and metabolomics allow simultaneously studying a large number of genes, proteins or metabolites, irrespective of their biological function. These new technologies will help to improve our understanding of the herbivore biology in a context of sustainable production. This short review presents some examples showing how "omics" may contribute to the improvement of economic production efficiency based on, for instance, the detection of markers of exposure to mycotoxins or of the potential to improve the metabolic and physiological efficiency of herbivores (partitioning of nutrients between tissues and organs, muscle differentiation for meat production, nutritional regulation of the expression of genes). "Omic" approaches can also contribute to the other pillars of sustainability: animal well-being (by revealing stress markers), protection of the environment (by controlling nitrogen emissions from the animals), and product quality (by controlling the fatty acid composition of products and by finding biomarkers of meat tenderness, and of milk and meat flavour).

Three diets for cows were used to evaluate the effect of extruded linseed (EL) or extruded linseed plus alpha-tocopherol (ELVE) supplementation of a maize silage diet (CO) on the odor-active compounds of Saint-Nectaire cheese. Cheese odor and flavor profiles were studied by sensory analysis. The volatile compounds were extracted by purge and trap and separated by gas chromatography. The odor compounds were detected and identified using an 8-way olfactometric device and a mass spectrometer. Twenty-nine volatile compounds were considered as contributing to the odor of Saint-Nectaire cheese. Half the compounds identified were known to be lipid degradation products but not all of them were affected by the diet. Among the markers of unsaturated fatty acid degradation, hexanal was not affected, whereas heptanal was increased more by the ELVE diet (6 times) than by the EL (3 times) diet. The ELVE diet led to cheeses with butanoic acid and heptanal odor peaks that were, respectively, 2 and 6 times higher than with the CO diet, which explained the lower milk odor and flavor scores obtained by sensory analysis on ELVE cheese. Although the cheese-making date had a greater effect than the diet on the aromatic profiles of the cheese, principal component analysis showed that the differences between cheeses obtained on the 3 diets were repeatable. The EL diet successfully enhanced cheese nutritional value without noticeably changing its flavor. alpha-Tocopherol supplementation was found to be unnecessary, as no oxidized odor was found.

Cantal cheese was made with either raw or pasteurized milk from cows led either pasture or a hay and concentrate diet, and was analyzed after 3- and 6-month aging. The cheese aroma was rather mild for pasteurized-milk cheese and rather strong for raw-milk cheese, and was little affected by the cows' feeding patterns. Gas chromatography of the volatile compounds coupled with a new 8-way olfactometry device revealed 42 odorous peaks. The major odour-active compounds were butanoic acid, 2,3-butanedione, 3-methylthio-propanal, hexanal, acetic acid, isobutanoic acid, and 1 -octen-3-ol. The intensity of butanoic acid was much stronger in raw-milk than pasteurized -milk cheese. The intensities of isobutanoic acid, pentanal, E-2-hexenal, cyclohexanone, tetra methyl pyrazi ne and y-heptalactone were lower in the 6-month-aged than the 3-month-aged cheeses, and only ethylbenzene intensity was higher. Isopentanoic acid odour was weaker when the milk had been obtained from cows fed a pasture diet. C) 2009 Elsevier Ltd. All rights reserved.

The last decade has seen important developments in the use of carotenoid pigments to authenticate pasture-feeding in ruminants. However, dehydrated alfalfa is sometimes incorporated in grain-based concentrates fed to stall-raised lambs, which may affect the reliability of the pasture-feeding authentication methods based on carotenoids in plasma and fat, due to significant residual carotenoid levels post-dehydration. The aim of this study was to examine whether other compounds can give additional information to authenticate diet and discriminate pasture-fed lambs from lambs fed high levels of alfalfa indoors. Two feeding treatments were compared: pasture-feeding (P) v. stall-feeding with dehydrated alfalfa (A). Each treatment group consisted of seven male Romanov × Berrichon lambs. Pasture-fed (P) lambs grazed a permanent graminaceae-rich pasture maintained at a leafy, green stage, offered ad libitum; they received no supplementation at pasture. A-group lambs were individually penned and fed dehydrated alfalfa and straw; their feed level was adjusted to achieve a similar growth pattern as for P-group lambs. Plasma carotenoid concentration was measured at slaughter by spectrophotometry. The reflectance spectrum of perirenal and subcutaneous caudal fat was measured at 24-h post mortem and used to calculate an index (absolute value of the mean integral (AVMI)) quantifying light absorption by carotenoid pigments present in the fat. The nitrogen (N) stable isotopes ratio (δ15N) in both feed and longissimus dorsi muscle was measured by isotopes ratio mass spectrometry (IRMS). Volatile compounds were analyzed in perirenal fat for five randomly chosen lambs per treatment, using dynamic headspace-gas chromatography-mass spectrometry. Plasma carotenoid concentration and AVMI of the fat did not differ significantly between P- and A-group lambs, but there were significant between-treatment differences in meat δ15N values and in the terpene profiles of perirenal fat. A discriminant analysis performed using three compounds in different animal tissues (δ-cadinene in perirenal fat, δ15N value of the meat and plasma carotenoid concentration) clearly separated pasture-fed lambs from lambs fed high levels of alfalfa indoors.

The aim of this experiment was to study the effect of the addition, to milk, of an essential oil (EO) obtained from the hydrodistillation of plants collected from a mountain natural pasture on the milk and cheese sensory properties. The EO was mainly composed of terpenoid compounds (67 of the 95 compounds identified) as well as ketones, aldehydes, alcohols, esters, alkanes, and benzenic compounds. In milk, the addition of this EO at the concentration of 0.1 microL/L did not influence its sensory properties, whereas at 1.0 microL/L, sensory properties were modified. In cheeses, the effect of adding EO into milk was studied in an experimental dairy plant allowing the production of small Cantal-type cheeses (10 kg) in 3 vats processed in parallel. The control (C) vat contained 110 L of raw milk; in the other 2 vats, 0.1 microL/L (EO1) or 3.0 microL/L (EO30) of EO were added to 110 L of the same milk. Six replicates were performed. After 5 mo of ripening, chemical and sensory analyses were carried out on the cheeses, including determination of the volatile compounds by dynamic headspace combined with gas chromatography-mass spectrometry. The EO did not influence the sensory properties of the cheeses at the lower concentration (EO1). However, the EO30 cheeses had a more intense odor and aroma, both characterized as "mint/chlorophyll" and "thyme/oregano." These unusual odors and aromas originated directly from the EO added. In total, 152 compounds desorbing from cheese were found, of which 41 had been added with the EO; in contrast, 54 compounds of the EO were not recovered in the cheese. Few volatile compounds desorbing from cheeses, other than the added compounds, were affected by EO addition. Among them, 2-butanol, propanol, and 3-heptanone suggested a slight effect of the EO on lipid catabolism. The antimicrobial activity of terpenes is not or is only marginally involved in the explanation of the influence of the botanical composition of the meadows on the pressed cheeses sensory properties.

There is currently an increased consumer demand for information on herbivore production factors, particularly animal diet. To meet these demands, farmers and commercial entities develop specifications via quality labels. There is therefore a need for analytical tools that may guarantee that the specification commitments have been fully met or to help constructing them. The nature of the diet strongly influences the composition of the animal tissues and products, which is due to specific compounds that are directly transferred from the feed to the end product or that are transformed or produced by ruminal microorganisms or the animal's metabolism under the effect of specific diets. Some of these compounds can therefore be used as diet markers. Moreover, differences in the meat and milk composition induce differences in their optical properties, therefore in their spectral features, which can also be used for diet authentication. This paper reviews the different approaches that have been investigated, some leading results concerning the comparison of contrasting feeding situations, together with the persistence and latency of appearance of some diet markers in the event of animal diet changes, and lastly some examples of implementation in the field with farmers that are interested in such methods.

Plant secondary metabolites such as terpenes, deposited in the fat of pasture-fed animals have been proposed as biomarkers in these animals. In this study, the accumulation of a variety of terpenes in muscle and adipose tissues was investigated in young bovines. Two calves were fed with artificial milk and two calves were administered the same artificial milk with a mixture of essential oils. Terpenes were analysed by gas chromatography-mass spectrometry in rectus abdominis intramuscular lipid, subcutaneous, intermuscular, perirenal and peritoneal adipose tissues. The enrichments obtained were weak. Terpenes appeared to preferably accumulate in perirenal and peritoneal fat. Sesquiterpenes were retained more than monoterpenes or their oxygenated derivatives in the tissues of the calves receiving essential oils. Tissue enrichment in the calves that had not ingested the essential oil was observed for a few terpenes, suggesting that lung absorption may also be an effective way of penetration.

The aim of this work was to study the variability in the composition of bulk milk mixtures of fat-soluble compounds (vitamins A and E, carotenoids, and terpenoids) and assess the links with milk production conditions. Milk from 10 collection trips in the French department of the Haute-Loire (10 to 36 herds per trip) was sampled in the tanker twice during the winter period and 3 times during the grazing season. The collection trips differed in their altitude (440 to 1,150 m) and the forage system (grass or based on corn silage). Vitamins A and E, carotenoids, and terpenoids of the 50 tanker loads of milk were analyzed. Data of milk production conditions in the 204 farms made it possible to constitute indicators for the collection trip and to define 50 mean herds. The relationships between mean herd characteristics (breed, stage of lactation, and feed) and milk characteristics were investigated. The constituents of tanker loads of milk were comparable to those observed in milk produced by groups of animals receiving contrasting diets (rich in concentrate or corn silage vs. pasture). The characteristics of the milk differed according to the period; those produced at grazing were more yellow (1.02 +/- 0.4; mean of difference) and richer in beta-carotene, lutein, vitamin E (2.0 +/- 1.2, 0.23 +/- 0.12, and 6.1 +/- 5.0 mug/g of fat, respectively), and sesquiterpenes (2.7 +/- 2.5) than winter. The variations observed for beta-carotene, lutein, and vitamin E were linked to the proportion of grazed grass or grass silage in the forage (r = 0.66, 0.69, and 0.51, respectively), unlike the vitamin A content. During grazing, 20 of the 32 terpenoids identified were associated with the proportion of permanent grassland available for grazing or cut. These results show that feeding is an effective way to modify the quality of dairy products, even in the case of bulk tank milk mixtures. Dairy plants could market different milks, which would contain specific compositions.

Les consommateurs sont demandeurs d’informations et de garanties sur les conditions d’élevage des animaux et en particulier sur leur alimentation. Ces préoccupations conduisent les filières animales à prendre des engagements sur les conditions d’élevage et d’alimentation des animaux, engagements spécifiés dans des cahiers des charges. Il apparaît ainsi un besoin d’outils analytiques permettant de garantir le respect de ces engagements et/ou d’aider à les instruire. La nature de l’alimentation influence fortement la composition des tissus et produits animaux. Ceci est dû à des composés spécifiques qui sont soit directement transférés de l’aliment au produit, soit transformés ou produits par les microorganismes du rumen ou le métabolisme animal sous l’effet de l’alimentation. Certains de ces composés peuvent donc, en retour, être utilisés pour tracer l’alimentation. De plus, les différences de composition des tissus et produits provoquent des modifications de leurs propriétés optiques, qui peuvent également être mises à profit. Cet article présente les différentes approches analytiques développées actuellement, les principaux résultats obtenus lors de la comparaison d’alimentations contrastées, puis lors de l’alternance de régimes alimentaires avec les questions de latence et de persistance des biomarqueurs d’intérêt, et enfin quelques exemples d’application sur le terrain avec certaines filières animales intéressées par ces outils.

Changes of terpene content in milk from cows grazing natural diversified upland pasture were examined in this observational trial. A homogeneous plot divided into 2 subplots was used from May 31 to July 1, 2003 (first growth) and again from October 1 to October 7, 2003 (vegetative regrowth). Each subplot was grazed by 6 dairy cows in 2 ways: strip grazing (SG), with new allocations of pasture strips at 2-d intervals, and paddock grazing (PG). The PG subplot was divided into 3 paddocks and the cows were moved to a new paddock on June 13 and June 24, 2003. Milk from the 6 cows was collected twice a week, pooled, and used for terpene analyses by dynamic headspace gas chromatography-mass spectrometry system. Twenty mono- and 23 sesquiterpenes desorbing from the milk fat were separated. The most abundant monoterpenes were beta-pinene, alpha-pinene, gamma-terpinene, limonene, alpha-tujene, terpinolene, and alpha-phellandrene. The most abundant sesquiterpenes were beta-caryophyllene, alpha-copaene, beta-cedrene, transmuurola-4-(14)-5-diene, beta-bisabolene, and delta-cadinene. Both mono- and sesquiterpenes in SG milk increased across time with an 8-fold increase in total terpenes in milk from the beginning to the end of June. In parallel, dicotyledons, including the main terpene-rich plants, increased from 17 to 31% of total biomass of the vegetation and the development of Dactylis glomerata progressed from boot to ripening stage. The terpenes in PG milk were equivalent to those in SG milk for the first paddock at the beginning of June and remained constant or doubled for the sum of mono- and sesquiterpenes, respectively. The lower variability of the PG milk terpene content could be related to the opportunity that PG cows had to choose ingested herbage, whereas the SG cows had limited choice within the smaller allocated pasture strips. Milk from cows grazing regrowth pastures in October contained low levels of terpenes, and values were similar for PG and SG milks. Change in the sum of monoterpenes is representative of changes for most monoterpenes (except for limonene) and, conversely, the change in the sum of sesquiterpenes mainly reflected changes in beta-caryophyllene and alpha-copaene. In addition to effects of botanical composition of pasture, it appears that terpene content in milk may vary according to factors linked to grazing management that need more intensive study. Nevertheless, current results raise questions about the precision of terpenes as feed tracers.