Cianzio D S, Topel D G, Whitehurst G B, Beitz D C, Self H L
J Anim Sci. 1985 Apr;60(4):970-6. doi: 10.2527/jas1985.604970x.
Forty crossbred steers of similar birth date and fed the same growing-finishing diet were used to study adipocyte changes in six fat depots during growth from 11 to 19 mo of age. Steers were slaughtered at 2-mo intervals. Adipose tissue samples were obtained from kidney, mesenteric and brisket fat and subcutaneous, intermuscular and intramuscular fat from the 10th to 12th rib section. The osmium tetroxide fixation technique was used for determination of cell size and number. Except for three brisket fat samples, distributions of adipocyte diameters from six different fat depots were monophasic during the age range considered in this study. At 17 mo of age, the mean adipocyte diameter, in decreasing order, was: kidney fat greater than mesenteric greater than subcutaneous greater than intermuscular greater than intramuscular greater than brisket fat. Fat deposition during growth to 19 mo of age occurred mainly by hypertrophy of adipocytes. An apparent cell hyperplasia occurred in the intramuscular fat depot from 11 to 15 mo and in the brisket fat depot after 15 mo of age. Based on cellularity characteristics, evidence exists to classify intramuscular and brisket fat depots as late-developing ones. Cell number/gram of intramuscular adipose tissue was a better predictor of marbling score than was fat cell diameter.
选用40头出生日期相近且采食相同生长育肥日粮的杂交阉牛，研究其在11至19月龄生长期间6个脂肪沉积部位的脂肪细胞变化。阉牛每隔2个月屠宰一次。从第10至12肋处采集肾周、肠系膜、胸下脂肪以及皮下、肌间和肌内脂肪的组织样本。采用四氧化锇固定技术测定细胞大小和数量。在本研究考虑的年龄范围内，除了3个胸下脂肪样本外，6个不同脂肪沉积部位的脂肪细胞直径分布均为单峰分布。17月龄时，平均脂肪细胞直径由大到小依次为：肾周脂肪＞肠系膜脂肪＞皮下脂肪＞肌间脂肪＞肌内脂肪＞胸下脂肪。生长至19月龄期间的脂肪沉积主要通过脂肪细胞肥大实现。11至15月龄时肌内脂肪沉积部位以及15月龄后胸下脂肪沉积部位出现明显的细胞增生。基于细胞特性，有证据表明可将肌内和胸下脂肪沉积部位归类为发育较晚的部位。每克肌内脂肪组织的细胞数量比脂肪细胞直径更能准确预测大理石花纹评分。
