Histopathological and ultrasonographic testicular evaluation of young bulls fed a hyperenergetic diet

Abstract

The objective of the present study was to carry out the andrological evaluation of young bulls fed a hyper-energetic diet by correlating traditional andrological data with the results of ultrasonographic and histological tests. The animals were kept in confinement for 94 days with an adaptation period of ten days. Three evaluations were performed with 28 day intervals between each. The animals were weighed and testicular morphometry, semen analysis, ultrasonographic testicular evaluation with a visual scale using the histogram method and histopathological evaluation were performed. Ponderal data, testicular biometry, sperm parameters and ultrasound data were not closely correlated after 94 days (r(2) < 0.3). Body weight (BW), scrotal circumference (SC) and testicular volume (TV) varied significantly across all the time periods (D28, D56 and D84). Visual ultrasound analysis revealed that the testicular stroma were homogenous until the 28th day, with minimal changes in echogenicity. By day 56, although the images remained homogeneous, hypoechoic areas had appeared. From the 84th day heterogenicity of the testicular stroma was observed in some animals. These included hypoechoic and hyperechoic areas, sometimes with both patterns in the same testis. Significant differences were observed between the visual and histological ultrasonographic analysis at the beginning of the experiment and on the 56th and 84th days (P < 0.05). The histological evaluation revealed several alterations which indicated inflammatory processes, such as the presence of fibrous connective tissue, as well as the atrophy and vacuolization of the cytoplasm, resulting in cellular degeneration. While nutritional management employing a hyperenergetic diet encouraged testicular and ponderal growth, it also resulted in the appearance of pathologies and visible changes to the echogenicity of the testicular stroma, confirmed by histological evaluation, which led to spermatogenesis disorders.