Université Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 St-Genès-Champanelle, France; Universidade Estadual de Maringá, UEM, Av. Colombo 5.790, CEP 87020-900 Maringá, PR, Brazil.
INRAE, UMR Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'Elevage, F-35590 St-Gilles, France.
Animal. 2022 Aug;16(8):100610. doi: 10.1016/j.animal.2022.100610. Epub 2022 Aug 5.
Pasture-feeding in lambs has been associated with dark-coloured meat and high meat contents of volatile indoles (skatole and indole), which may be responsible for sensory defects. The risk of off-flavours is even higher when lambs graze alfalfa, because it is particularly rich in rapidly degradable proteins. Here, we investigated whether a short concentrate stall-finishing period in lambs that previously grazed alfalfa influences meat sensory quality traits. We compared three feeding treatments, using three groups of 10 male Romane lambs: grazing alfalfa (A), stall-feeding with concentrate and straw (S), and stall-finishing with concentrate and straw for 21 days after previously grazing alfalfa (AS). During stall-feeding, the concentrate was given at a level adjusted to achieve a similar growth pattern in all treatment groups, and the length of the trough was sufficient for all lambs to have access to the feeds at the same time. Lamb live weight and age at slaughter, and carcass conformation and fatness were similar for all treatment groups. Perirenal fat skatole content was lower in AS and S lambs than in A lambs (P < 0.001 and P < 0.05, respectively), and not significantly different between AS and S lambs. Perirenal fat indole and dorsal fat skatole concentrations were lower in AS lambs than in A lambs (P < 0.05 and P < 0.005, respectively), the other pairwise comparisons being not significant. There was no treatment effect on dorsal fat indole content. Longissimus et lumborum muscle colour coordinates differed between pasture-fed and stall-fed lambs, with a lower lightness (P < 0.005) and greater redness and hue angle (P < 0.001 and P < 0.01, respectively) in pasture-fed lambs, but muscle colour coordinates did not differ between A and AS lambs. A 21-d concentrate-based stall-finishing period in lambs previously raised on alfalfa pasture therefore markedly reduced fat indoles concentrations compared to lambs grazed on alfalfa until slaughter but did not change meat colour.
羔羊放牧与深色肉和挥发性吲哚（粪臭素和吲哚）含量高有关，这可能是导致感官缺陷的原因。当羔羊放牧苜蓿时，异味的风险更高，因为苜蓿特别富含快速降解的蛋白质。在这里，我们研究了之前放牧苜蓿的羔羊短期集中育肥期是否会影响肉的感官质量特性。我们比较了三种喂养处理方法，使用三组 10 只罗曼公羊：放牧苜蓿（A）、集中育肥与稻草（S）、放牧苜蓿后集中育肥 21 天（AS）。在集中育肥期间，根据所有处理组相似的生长模式调整精饲料的投喂量，并且食槽的长度足以让所有羔羊同时进食。所有处理组的羔羊活重和屠宰时的年龄、胴体形态和脂肪含量相似。肾周脂肪粪臭素含量在 AS 和 S 组羔羊中低于 A 组羔羊（P<0.001 和 P<0.05），而 AS 和 S 组羔羊之间没有显著差异。AS 组羔羊的肾周脂肪吲哚和背脂粪臭素浓度低于 A 组羔羊（P<0.05 和 P<0.005），其他组间比较无显著差异。背脂吲哚含量不受处理的影响。放牧和舍饲羔羊的背最长肌颜色坐标不同，放牧羔羊的亮度较低（P<0.005），红色和色调角较大（P<0.001 和 P<0.01），而 A 组和 AS 组羔羊的肌肉颜色坐标没有差异。因此，之前在苜蓿牧场上饲养的羔羊在育肥期内以浓缩饲料为主，持续 21 天，与放牧直到屠宰的羔羊相比，显著降低了脂肪吲哚的浓度，但没有改变肉色。
