To evaluate the effect of stocking density and transport time on physiological responses and meat quality, 72 male suckling lambs were transported by road to the slaughterhouse at three different stocking densities (0.12, 0.20 or 0.25 m2/lamb) and two transport times (5 h or 30 min). Blood samples were collected pre-transport at the farm and after unloading in the slaughterhouse to measure levels of cortisol, creatine kinase (CK) and lactate dehydrogenase (LDH). After slaughter, the weights of the hot carcass, liver and spleen were recorded and pH in Musculus longisimus thoracis et lumborum (L), Musculus semitendinosus (ST) and Musculus psoas major (PM) were determined. Colour, water-holding capacity (WHC), texture and thiobarbituric acid-reactive substances (TBARS) values were measured in samples of L, at 24 h post mortem and after 5 days of ageing. Cortisol and LDH were higher in suckling lambs transported for 30 min than those transported for 5 h. Stocking density did not affect blood parameters studied. Transport time significantly affected some carcass quality parameters, but stocking density had no significant effect. Suckling lambs transported for 5 h had lower liver weights and dressing percentages than those transported for 30 min. Transport time influenced pH values, with lambs subjected to the longer journey showing the lowest pH at 0 h in the three muscles studied, with the lowest final pH in L and PM. The PM lambs transported at high density (0.12 m2/lamb) had the lowest pH at 24 h. Transport time and stocking density did not greatly affect colour and texture parameters. The meat from lambs transported for 30 min had higher WHC than meat from lambs transported for 5 h. Animals transported for longer journeys showed higher lipid oxidation after 5 days of ageing than those transported for 30 min. Loading and initial transport caused significant stress response in suckling lambs, that stress response was reduced over the time course of the journey.

The aim of this work was to improve the fatty acid profile of meat from light lamb, frequently reared in Spain and in other Mediterranean countries. A total of 44 light lambs fed different n-3 polyunsaturated fatty acids sources were studied: control (C) (palm oil), extruded linseed (L), extruded linseed mixed with microalgae (LM) and fish oil (FO). The productive performance from 14.7 to 26.2 kg of live weights and meat quality characteristics during refrigerated storage were assessed. Lambs fed FO showed lower feed intake (p <0.001), average daily gain (p <0.001) and higher feed conversion ratio (p <0.001) than lambs from the other treatments. Fish oil meat had the lowest (p <0.01) protein proportion and the highest (p <0.001) C20:5n-3, C22:5n-3 and C22:6n-3 proportions, while L or LM produced the highest (p <0.001) C18:3n-3 deposition. Fish oil meat had higher (p <0.05) L* and lower (p <0.001) a* than meats from the other treatments. After 7 days of storage, FO meat showed the highest TBARS (p <0.001), while C meat showed similar value to 0 days of storage. Additionally, FO underwent higher microbial growth after 7 days of storage as compared to the other treatments. Dietary supplementation with L and LM leads to C18:3n-3 meat enrichment and to a microbial load and colour characteristics similar to those of C, without adverse effect on lamb performance. However the use of FO improves the fatty acid profile of meat, but negatively affects lamb performance and meat quality.