Testicular growth and testosterons production in maturing domestic chicks
1981
Khan, S.A. | Begum, A. | Khan, M.S. (Diabetic Association of Bangladesh, Dacca)
Testicular growth and testosterone production, comb and spur growth were studied in maturing male chicks. Plasma testosterone concentrations were measured by a sensitive radioimmunoassay. Up to 5-months old, chicks weighed less than 0.5g. From 5 months up to testicular growth was observed, reaching a weight of about 3g at 6 months and nearly 7g by 7 months. The rate of the testicular growth "K" was less than 0.03 up to 5 months but 0.11 and 0.23 at 6 and 7 months respectively. Similarly, the Gonadosomatic Index (GSI) increases from 5 months up values being more than 15 at 6 and 7 months, in contrasts to less than 7 at below 5 months. However, increase in plasma testosterone levels (less than 0.2 ng/ml at 3 months to 1.29 ng/ml at 4 months and 2.0ng/ml at 5 months preceded the testicular growth, indicating the Leydig cell maturation occurred prior to tubule growth. Increase in testosterone concentrations was followed by the growth of the comb and spur, which were testosterone-dependent secondary sex characters. Testicular histology showed mitotic activity in the spermatogonia in 5-month old chicks and spermatozoa in 7-months chicks.
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