藏绵羊及其与白萨福克羊杂交后代背最长肌肌纤维特性研究

Study on the Fiber Characteristics of Longissimus Dorsi Muscle of Tibetan Sheep and Their Crossbred Offspring with White Suffolk Sheep

本试验旨在研究舍饲6、8、12月龄的藏绵羊及其与白萨福克羊杂交后代背最长肌的肌纤维特性。选取体重接近、自然断奶6月龄藏绵羊和白萨福克羊×藏绵羊杂交羊公羊各20只,进行为期6个月的饲喂试验。舍饲管理采用青干草+精料补充料方式饲喂。在6、8、12月龄分别随机选择4只藏绵羊和杂交羊进行屠宰,采集背最长肌样品,进行石蜡切片的制作、观察和分析。结果表明,随着月龄的增加,藏绵羊和杂交羊6、8、12月龄背最长肌的肌纤维面积和直径显著增大(P<0.05),肌纤维密度显著减小(P<0.05)。对藏绵羊和杂交羊的背最长肌进行差异显著性分析的结果显示,6月龄藏绵羊和杂交羊背最长肌肌纤维的面积、直径和密度无显著性差异(P>0.05),8月龄和12月龄藏绵羊的肌纤维面积和直径显著大于杂交羊(P<0.05),肌纤维密度显著小于杂交羊(P<0.05)。由此可见,舍饲育肥条件下,白萨福克羊×藏绵羊杂交羊肉品质较好,杂种优势明显;藏绵羊和白萨福克羊×藏绵羊杂交羊周岁以内的肉品质较为优良,可适用于缩短养殖周期,实现当年出栏的生产需求。

The aim of this study was to research the fiber characteristics of longissimus dorsi muscle of Tibetan sheep and their crossbred sheep with white Suffolk sheep at the age of 6,8,and 12 months.There were 20 male Tibetan sheep and crossbred sheep with approximate weight and natural weaning age of 6 months respectively selected to dry-lot feeding for 6 months.The feeding mode of green hay and concentrate supplement was used in the whole experimental stage.At the age of 6,8 and 12 months,4 Tibetan sheep and crossbred sheep were randomly selected for slaughter,and the samples of longissimus dorsi muscle were collected for paraffin section preparation,observation and analysis.The results showed that the area and diameter of muscle fiber of longissimus dorsi muscle of Tibetan sheep and crossbred sheep at 6,8,and 12 months increased significantly(P<0.05)and the density of muscle fiber decreased significantly(P<0.05)with the increase of age.The results of significant difference analysis on the longissimus dorsi muscle of Tibetan sheep and crossbred sheep showed that the area,diameter and density of longissimus dorsi muscle fiber of 6-month-old Tibetan sheep and crossbred sheep had no significant difference(P>0.05).The area and diameter of muscle fiber of Tibetan sheep aged 8 and 12 months were significantly larger than those of crossbred sheep(P<0.05),while the density of muscle fiber was significantly smaller than that of crossbred sheep(P<O.05).In summary,the crossbred sheep of White Suffolk×Tibetan sheep shown an outstanding heterosis with a better meat quality.The meat quality of Tibetan sheep and crossbred sheep within one year of age was relatively good,which can be used to shorten the breeding cycle and meet the production demand of offtake in the current year.