Relationships among Measures of Testicular Development and Endocrine Function in Boars

Abstract

SummaryNine blood samples were taken at 30-min intervals from 36 Landrace x Large White boars at each of eight ages (42, 56, 70, 84, 98, 112, 126 and 140 d). Serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) and estradiol-1713 (E2) were quantified by radioimmunoassay procedures. The maximum concentration of LH and the age at maximum concentration were predicted for each boar. Variability of LH samples was described for each boar by the pooled within age variance among LH samples and by the number of LH peaks. Measurements of testicular development taken at 140 d of age included: in situ testis width and length, excised testis weights and histological traits of excised testes (seminiferous tubule diameter, percentage of tubules with a lumen and percentage of tubules with active spermatogenesis). Pooled within line correlations were calculated with data from boars selected for either high or low testis weight. Correlations among the testicular traits ranged from .45 to .88. Luteinizing hormone concentration (mean over all ages) was related to measures of testicular development (r = .24 to .49). Concentrations of LH from 42 to 84 d of age were more highly correlated with testicular traits than were the concentrations from 98 to 140 d. Boars with larger, more mature testes tended to have higher maximum concentrations of LH (r = .19 to .42) and younger age at maximum concentration (r = -.12 to -.26).

Comparison of circulating concentrations of reproductive hormones in boars of lines selected for size of testes or number of ovulations and embryonal survival to concentrations in respective control lines.

“…1 and 2 indicated no important differences in circulating concentrations of FSH among boars from TS and C lines. This supports previous work (Schinckel et al 1984) in which boars with larger testes had concentrations of FSH similar to those of boars with smaller testes during sexual maturation. Based on data from the present experiments, there are no differences in feedback regulation of 17b-estradiol on the hypothalamic-pituitary axis in modulation of FSH secretion between boars in the TS and C lines.…”

Improvement of Sperm Production in Subfertile Boars byCordyceps militarisSupplement

“…Although cordycepin can induce the steroidogenic enzyme E2 and testosterone (Hsu et al, 2003;Huang et al, 2004), its effect on FSH has not been reported and awaits future study. Boars with high testes weight had a more rapid increase in E2 concentrations than did boars with low testes weight (Schinckel et al, 1984a(Schinckel et al, , 1984bZanella et al, 1999). The sperm transit through the epididymis takes approximately 10 days in pigs.…”

Active Immunization of Prepubertal Boars Against Testosterone: Testicular and Endocrine Responses at 14 Months of Age

“…Moreover, estrogen concentrations in plasma were similar for both groups, which would indicate a similar degree of interstitial cell activity within the testes of treated and control boars (Raeside and Renaud, 1983). Schinckel et al (1984b) found no correlation between average LH and FSH concentrations in boars for blood samples collected from 42 to 140 d of age. However, mean concentrations of both gonadotropins varied in a similar manner over time in boars selected for high or low testicular weight (Schinckel et al, 1984a).…”