Qualité Des Lipides Et Des Acides Gras De La Viande D’agneau De Race Locale Nourri A Base D’herbe Des Pâturages En Algérie

Abstract

This study aims to evaluate and compare the effect of grass and standard feed on nutritional and sensory meat quality. 48 lambs of Rumbi breed were used in this trial, in which they were organized in 4 groups (n=12). Three groups were raised on pasture at arid (A) and Semi-Arid (SA) and Wet (W) areas in west of Algeria during 100days. The fourth group was bred indoors by Concentrate feed (C). The zoo technical parameters at the end of the experiments showed that lambs from group C were heavier (48.04 vs 29.84 (A) and 28.13 (SA) and 24.23 (H)). The blood parameters (day 60 and day 90) did not reveal a significant differences between the groups except for triglycerides .After slaughter, carcasses from A, SA and W groups were leaner (14.60 and 14.38 and 11.63 vs 23.93kg (C) after cooling ,respectively .The Samples of longissimus dorsi (LD) were removed and analyzed. In average, untrimmed samples have presented comparable total lipids content 20vs23% and trimmed ones have shown 8,3 vs 16.44% of total fat (p <0.001) respectively for meat pasture A, SA and H in comparison with the meat based food standard C).The Polyunsaturated fatty acids (PUFA) ω3 were significantly higher in the raw meat from grass than in meat from concentrate 89vs49mg / 100g (p <0.04) dominated by C18: 3 n-3 (ALA) which showed a significant amounts in the samples (A ) 72mg / 100g, compared to samples (SA) and (W) respectively 47 and 46 mg / 100mg vs 32mg / 100 g (C) .The DPA (C22: 5 n-3) is three times higher (P <0.001). The quantities of PUFA n-6 are lower in meat from grass tests 211,33vs542mg / 100g (p <0.001), represented by linoleic acid (LA) C18: 2 n-6c in average 153vs396mg / 100g (P <0.001). The contents of AGS in meat from grass are half of the ones from concentrate (2653,7 vs 5626mg /100g)(P<0,001). The palmitic acid (C16: 0) and the stearic acid (C18: 0) decreased significantly ( 1328vs2903 and 944,7vs2240mg / 100g) respectively .the cooking process increases the concentration of TL, 31% vs 15.73% in meat from grass versus meat from concentrate , respectively (P <0 .001). The PUFA n3 in cooked meat from pasture were high 113 vs 51mg / 100g (P <0 .001) especially in C18: 3 n3 71 vs. 29mg / 100g (P <0.003), and followed by the DPA 17 vs 6mg / 100g (P <0.001) . The quantities of PUFA n-6 were significantly low 291 vs 700mg / 100g (P <0.001), represented by LA 213 vs. 510mg / 100g (P <0.001). In consequence, the n6 / n3 and LA / ALA ratios have significantly decreased 2.63 vs 12.08 and 3.37 vs 14.31 in average , respectively between meat from grass and from concentrate(P <0.001) .in the other hand , Color and flavor which characterize the sensory quality seem to be protected against the oxidation of polyunsaturated fatty acids in help of antioxidants factors like vitamin E and polyphenol in grass . Based on these results and from a fattening perspective, grazing is declared to be a husbandry system economically sustainable; it needs a promotion to seek new opportunities for the production of the main organic food such as light lamb meat.