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.

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 improve the knowledge on young suckled Salers bull production and to study the effect of forage type and concentrate level on performance, carcass and muscle characteristics as well as on meat quality. Twenty-four Salers male calves of 150 days of age were assigned to six groups: C0 (fed exclusively with hay and dam's milk and slaughtered at approximately 6 months of age), and HH (hay - high concentrate), HL (hay - low concentrate), GH (cut grass - high concentrate), GL (cut grass - low concentrate) and CP (control pasture: pasture - high concentrate) groups differing in feeds received until slaughter and slaughtered unweaned at approximately 10 months of age. Carcass weights averaged 210 kg at 10 months of age at slaughter. Average daily weight gain (ADWG) in HH and GH groups tended to be higher (P = 0.09) than in HL and GL groups (1354 v. 1248 g/day). ADWG in CP group (1542 g/day) was higher (P < 0.05) than in the other groups. Carcass weight in CP group (230 kg) tended to be higher (P < 0.1) than in HL (198 kg) and GL (200 kg) groups. Carcass muscle weight was higher (P < 0.05) in GH (155 kg) and CP groups (165 kg) than in HL (141 kg) and GL (142 kg) groups. Carcass and offal fatty tissue weights and carcass fatness did not differ between groups. Neither forage type nor concentrate level had significant effect on the area of muscle fibres or on muscle metabolic enzyme activities (namely, lactate dehydrogenase - LDH, phosphofructokinase - PFK, isocitrate dehydrogenase - ICDH, citrate synthase - CS and cytochrome-c oxidase - COX). semitendinosus muscle of CP group presented higher CS enzyme activities (8.10 μmol/min per g) than HH (5.30 μmol/min per g) and GL (4.52 μmol/min per g) groups. Neither total nor insoluble collagen content significantly differed between groups. Lipid content in rectus abdominis muscle was relatively low (average 67.5 mg/g dry matter) and was not affected by diet (P > 0.05). The ratio between n-6 and n-3 polyunsaturated fatty acid content was lower (P = 0.01) in the low-concentrate-fed than in the high-concentrate-fed group (3.95 v. 5.37, respectively). Sensory analysis noted that longissimus thoracis muscle from CP animals was more tender and juicy than that from HH and GH animals (P < 0.05).

The objective of the present study was to test the reliability of the analysis method of the reflectance spectrum of fat in the zone of light absorption by carotenoid pigments developed in lambs to trace grass feeding in calves. Six feeding treatments were compared in suckling calves: ad libitum cocksfoot hay plus ad libitum concentrate or half level of ad libitum concentrate (HH and HL), ad libitum cut grass plus ad libitum concentrate or half level of ad libitum concentrate (GH and GL), ad libitum highland grazed grass plus ad libitum concentrate (PH); ad libitum medium quality cocksfoot hay plus dam's milk (CO). Groups HH, HL, GH, GL and PH were slaughtered at approximately 10 months of age, after 150 days of experimental feeding diet. CO calves were slaughtered at the beginning of the experiment at approximately 6 months of age. The concentration of carotenoids was analysed by HPLC on diets and calves' plasma at slaughter. The reflectance spectrum of perirenal and subcutaneous fat were measured at slaughter and expressed as AVI units. Plasma carotenoid content was higher (P < 0.05) in PH and GL calves than in HH, HL and GH calves. There was an effect (P < 0.05) of feeding treatment and measurement site on AVI. Values obtained for perirenal fat were higher (P < 0,05) than those obtained for subcutaneous fat. For plasma carotenoid content and for AVI values in both fat tissues there was no overlapping between hay-fed calves on the one hand and GL or grazing calves on the other hand. However, there was some overlapping between hay-fed calves and GH calves. For plasma carotenoid content, values for CO calves overlapped with values of GH and GL calves. For both fat tissues AVI values of CO calves overlapped with values of HH, HL, GH and GL calves. A VI of cut grass fed calves (GH and GL groups) increased linearly (P < 0.05) with average daily grass intake for both tissues considered. AVI in subcutaneous fat tissue decreased linearly (P < 0.05) with average daily concentrate intake but this relation was not significant for AVI in perirenal fat (P > 0.05). Plasma carotenoid concentration and the reflectance spectrum of the fat in the zone of light absorption by carotenoid pigments could be used to trace grass feeding in calves. Results obtained in this study suggest that different fatty tissues could differ in their reliability and interest for traceability of grass-feeding, depending on the animal age and production system.