Un mode de conduite biologique et un niveau élevé d'herbe améliorent la qualité nutritionelle des acides gras de la viande chez l'agneau engraisse au pâturage

This study aimed at comparing the nutritional quality of meat fatty acids (FA) of pasture-fed lambs reared organically or conventionally and offered two levels of herbage availability. Forty eight castrated male lambs of Limousine breed were used in a 2 x 2 experimental design, i.e. production system (Organic –O- vs. Conventional –C-) x level of herbage availability (High vs. Low). The O and C pastures differed in the level of on-pasture mineral N fertilization (0 vs. 100 U. ha-1. year-1) since 10 years. The level of pasture availability was managed to obtain a mean lamb age at slaughter of 5 vs. 6 months in the High and the Low level respectively. GLC analysis of fatty acids from the Longissimus thoracis muscle showed that organic farming system improved the health value of lamb meat by decreasing the level of saturated FA and especially 16:0, thus leading to a higher value of polyunsaturated FA (PUFA) to saturated FA ratio (+15%, P<0.03) and increasing the level of CLA (+18.2%, P< 0.002). The high level of herbage availability led to a better nutritional and health value of meat FA by increasing significantly deposition of n-6 PUFA (+16.3%), n-3 PUFA (+15%) and CLA (+20.2%) in LT muscle to the detriment of saturated FA (-3.4%). In conclusion, the present study confirmed the general interest of pasture-feeding on the nutritional quality of the lamb meat. It showed, for the first time, the beneficial impact of organic farming on the health value of lamb meat FA by favouring deposition of PUFA (compared to saturated FA) and CLA, this effect being reinforced by a high level of pasture availability

Qualités de la viande d’agneaux d’herbe produits en élevage biologique ou conventionnel

La mention "Agriculture Biologique" sur un produit garantit une manière de produire, mais l’obligation de résultats est limitée à la conformation et l’état d’engraissement de la carcasse, d’où des questions sur les qualités alimentaires du produit viande

Comparison of the meat and carcass quality of lambs raised in organic or conventional production systems.

The ‘organic’ label on a product guarantees that synthetic fertilisers, pesticides and hormones are not used in the production process and that the use of pharmaceutical products and drugs is limited. However, product quality is often questioned and we have to anticipate the consumer demand for product quality guarantees. This study was conducted to compare the sensory and nutritional meat and carcass qualities of lambs raised under an organic (O) or a conventional (C) production system. Comparisons were made with both pasture-fed lambs and lambs that were stall-fed indoors with concentrate and hay. The experiment was conducted over two years for stall-fed lambs (S) (group O, n=24; group C, n=24) and three years for pasture-fed lambs (P) (group O, n=36; group C, n=36). For P lambs, O and C production systems differed in terms of the level of mineral N fertilisation of the pasture. For S lambs, the feed was organic vs. conventional, and the ingredients of O and C concentrates were the same. The nutritional quality of the meat (longissimus dorsi) was assessed in terms of its fatty acid (FA) composition, and the sensory quality of the loin chop was assessed by a trained sensory panel. In stall-fed lambs, the health value of meat FA for human consumption was higher in the O group than in the C group, but there was no difference in the sensory quality of the meat and the carcass between the O and C groups. In pasture-fed lambs, there were no significant differences between the O and C groups in terms of the health value of meat FA. However, in pasture-fed lambs, the loin chops had a higher level of abnormal odour of the fat in the organic than in the conventional group, probably due to a higher proportion of white clover in the diet