Karabinus D S, Evenson D P, Jost L K, Baer R K, Kaproth M T
Department of Chemistry, South Dakota State University, Brookings 57007.
J Dairy Sci. 1990 Sep;73(9):2364-71. doi: 10.3168/jds.S0022-0302(90)78919-9.
Random samples of cryopreserved, milk-extended semen, collected from 20 Holstein bulls at about 14 mo of age (young) and again at about 4 yr of age (mature), were evaluated at thawing and during 3-h incubation to compare semen quality of young versus mature bulls. Evaluation by differential interference contrast microscopy showed greater proportions of cytoplasmic droplets in semen from young versus mature bulls. Mature bulls exhibited greater proportions of intact acrosomes in freshly thawed semen than did young bulls. Evaluation of sperm chromatin structure by flow cytometry after staining with acridine orange showed lower values for mature versus young bulls, indicating resistance of DNA in nuclear chromatin to acid denaturation increased with age. Correlations between ages for most sperm morphology, acrosome integrity, and flow cytometry variables were high and positive. Nonreturn rate for young bulls was positively related to morphologically normal sperm and acrosomal integrity and negatively related to flow cytometry traits. Results suggest semen quality of young bulls was related to subsequent quality as mature bulls. With flow cytometry, differences were detected between semen samples that were not evident with light microscopy.
从20头荷斯坦公牛身上采集了冷冻保存的、经牛奶稀释的精液随机样本，这些样本分别在大约14月龄（年轻）和大约4岁（成熟）时采集，在解冻时以及3小时孵育期间进行评估，以比较年轻公牛与成熟公牛的精液质量。通过微分干涉对比显微镜评估发现，年轻公牛精液中的细胞质滴比例高于成熟公牛。成熟公牛刚解冻精液中的完整顶体比例高于年轻公牛。用吖啶橙染色后通过流式细胞术评估精子染色质结构，结果显示成熟公牛的值低于年轻公牛，这表明核染色质中的DNA对酸变性的抗性随年龄增长而增加。大多数精子形态、顶体完整性和流式细胞术变量之间的年龄相关性高且呈正相关。年轻公牛的不返情率与形态正常的精子和顶体完整性呈正相关，与流式细胞术特征呈负相关。结果表明，年轻公牛的精液质量与成熟后的质量相关。通过流式细胞术，检测到了光学显微镜下不明显的精液样本之间的差异。
