Effect of geographic origin and grazing system on lambs’ carcass traits and meat properties

Yathreb Yagoubi; Ilyes Mekki; Souha Tibaoui; Samir Smeti; Naziha Atti

Yathreb Yagoubi INRA-Tunisia
Ilyes Mekki University of Carthage, INRA-Tunisia, Laboratoire des Productions Animale et Fourragère, Rue Hédi Karray, 2049 Ariana, Tunisia
Souha Tibaoui University of Carthage, INRA-Tunisia, Laboratoire des Productions Animale et Fourragère, Rue Hédi Karray, 2049 Ariana, Tunisia
Samir Smeti University of Carthage, INRA-Tunisia, Laboratoire des Productions Animale et Fourragère, Rue Hédi Karray, 2049 Ariana, Tunisia
Naziha Atti University of Carthage, INRA-Tunisia, Laboratoire des Productions Animale et Fourragère, Rue Hédi Karray, 2049 Ariana, Tunisia

Keywords: geographic origin; grazing system; carcass; meat quality; lipid oxidation

Abstract

Consumer preferences are shifting from meat quantity to its nutritional value and sensory qualities. Then, this study aimed to evaluate the effects of geographic origin and grazing system on carcass and meat quality specifically focusing on mountain “Djebel” lamb meat. For that, thirty-six lambs (6 months-old) were used: 12 from the mountainous “Djebel” areas in Northwest Tunisia, 12 from “East”, and 12 from “Centre”. The Djebel group grazed natural forests with woody species, while the other groups grazed herbaceous pasture and received concentrate (400g/head/day) and hay supplementation (500 g /head/day). The couple of coordinates (altitude in meter and distance from the sea in km) were 1000 with 37 for Djebel, 44 with 46 or East and 895 with 151 or the Centre. All lambs were slaughtered at 25.8, 26.8, and 22.6 kg for Djebel, East and Centre, respectively, to study the meat quality attributes.

The lambs’ tissular composition was affected by lamb origin (P< 0.05) except to muscle proportion, which remained consistently around 60% across all groups. The meat pH was higher for lambs from Djebel and East than Centre group. The water cooking loss was significantly higher for East and Centre groups compared to that of Djebel one. The higher values of dry matter and crude protein were recorded in meat issued from Centre groups compared to Djebel and East groups. Meat redness (a*), chroma (C*) and Hue angle (H*) were not affected by the lamb’s origin, however lightness (L*) and yellowness (b*) were highly affected. The storage time has significantly affected the meat colour parameters. Lipid oxidation was lower in the Djebel group; however, it increased progressively for all groups during 9 days of storage until reaching 0.359 mg MDA/ kg meat but without exceeding the meat rancidity threshold. Lamb origin did not affect meat tenderness and juiciness; however, flavor and overall impression were higher for lambs from Djebel and Centre areas. In conclusion, lambs grazing in the natural forests of the Djebel region produced meat with a higher ultimate pH and lower cooking loss, and their meat demonstrated an extended shelf life due to increased antioxidant capacity during storage, indicating superior nutritional quality.