At 35 wk of age, testes were large and histologically mature in all 8 birds from both lighting treatments, and all birds were producing semen. Spermatozoa were present in the lumen of seminiferous tubules of all LL birds at 23 and 35 wk and in the SL birds at 35 wk (Fig. 4A). No spermatozoa were present in the lumen of seminiferous tubules of the LL and the SL groups of birds at 13 wk, or of the SL group at 23 wk (Fig. 4B).
Pulses of both LH and T were detected in birds serially bled at all three ages in both lighting treatments (Fig. 5). Concordances between LH and T pulses were 34% at 13 wk, 78% at 23 wk, and 71% at 35 wk, based on overlapping of pulses of LH and T with pulses determined using the PULSAR algorithm. Most pulses of T were preceded by LH pulses at all ages. However, some pulses of T were detected without detectable prior or post-pulses of LH, and vice versa, especially at 13 wk of age (Fig. 5). birth control yasmin
Overall mean concentrations of LH were lower at 13 wk of age than at 23 and 35 wk of age (p < 0.05) but not different between 23 and 35 wk of age (Fig. 6A). Higher overall mean concentrations were present in the LL group at 23 wk of age, but no differences were detected between lighting treatments at 13 and 35 wk of age. Baseline levels of LH were significantly different between the three ages ( p < 0.05). No differences were found between lighting treatments at 13 wk of age (p > 0.05), but the baseline level was significantly higher at 23 wk of age and significantly lower at 35 wk of age (p < 0.05) in the LL group than in the SL group (Fig. 6B).
FIG. 4. Histology of testis. A) Mature testis, representative of turkeys from the LL group at 23 wk of age and both the LL and SL groups at 35 wk of age; B) immature testis, representative of turkeys from both the LL and SL groups at 13 wk of age and the SL group at 23 wk of age (X200).
FIG. 5. Profiles of LH and T concentrations from individual turkeys at 13 (B#4, 8), 23 (B#12, 15), and 35 (B#18, 21) wk of age. B#4, 12, and 18 are from the LL group; B#8, 15, and 21 are from the SL group. The line with solid symbols indicates LH; the line with open symbols indicates T. Presence of symbols indicates points within peaks detected by PULSAR analysis. Thin lines in each panel indicate the presence of LH peaks, and thick lines indicate the presence of T peaks. The heavy bar at the top indicates the scotophase in the SL group.
FIG. 6. Overall mean (A), baseline (B), pulse numbers (C), and amplitude concentrations (D) of LH (mean ± SD), trial 3. Different letters within a group (age or treatment within age) indicate significant differences (p < 0.05); n = 8 for each age, n = 4 for each age/treatment.