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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Impaired protamination and sperm DNA damage in a Nellore bull with high percentages of morphological sperm defects in comparison to normospermic bulls

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Author(s):
Carreira, J. T. [1] ; Trevizan, J. T. [2] ; Kipper, B. H. [2] ; Perri, S. H. V. [2] ; Carvalho, I. R. [2] ; Rodrigues, L. H. [3] ; Silva, C. [4] ; Koivisto, M. B. [2]
Total Authors: 8
Affiliation:
[1] Ctr Univ Rio Preto, UNIRP, Sao Paulo, SP - Brazil
[2] Univ Estadual Paulista, Fac Med Vet, Aracatuba, SP - Brazil
[3] Self Employed Veterinarian, Sertaozinho, SP - Brazil
[4] CRVLagoa, Sertaozinho, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: Arquivo Brasileiro de Medicina Veterinária e Zootecnia; v. 67, n. 2, p. 417-423, MAR-APR 2015.
Web of Science Citations: 2
Abstract

The routine semen evaluation assessing sperm concentration, motility and morphology, does not identify subtle defects in sperm chromatin architecture. Bulls appear to have stable chromatin, with low levels of DNA fragmentation. However, the nature of fragmentation and its impact on fertility remain unclear and there are no detailed reports characterizing the DNA organization and damage in this species. The intensive genetic selection, the use of artificial insemination and in vitro embryo production associated to the cryopreservation process can contribute to the chromatin damage and highlights the importance of sperm DNA integrity for the success of these technologies. Frozen-thawed semen samples from three ejaculates from a Nellore bull showed high levels of morphological sperm abnormalities (55.8±5.1%), and were selected for complementary tests. Damage of acrosomal (76.9±8.9%) and plasma membranes (75.7±9.3%) as well as sperm DNA strand breaks (13.8±9.5%) and protamination deficiency (3.7±0.6%) were significantly higher compared to the values measured in the semen of five Nellore bulls with normospermia (24.3±3.3%; 24.5±6.1%; 0.6±0.5%; 0.4±0.6% for acrosome, plasma membrane, DNA breaks and protamine deficiency, respectively) (P<0.05). Motility and percentage of spermatozoa with low mitochondrial potential showed no differences between groups. This study shows how routine semen analyses (in this case morphology) may point to the length and complexity of sperm cell damage emphasizing the importance of sperm function testing. (AU)