Gametogenic responses of the testis in spotted munia (Lonchura punctulata;aves) to oral administration of lithium chloride

In the present study, the effects of orally-administered lithium on testicu lar morphology were examined in the spotted munia (Lonchura punctulata), a seasonally breeding sub-tropical finch. Adult males were procured from natu ral populations during the month of August, a time when these birds begin t o show seasonal reproductive maturity in an annual cycle. Both during the p eriod of acclimation, and throughout the subsequent experimental period, th e birds were maintained in an open aviary simulating natural environmental conditions. Lithium was dissolved in distilled water and was administered v ia the oral route by means of a commercially available stomach-tube. A tota l of five experimental groups were utilized. The first group (Group A) serv ed as control and received lithium-free distilled water in a similar manner . In the remaining four groups, lithium was administered daily as follows: Group B (2.5 mEq/Kg body weight for 5 days); Group C (2.5 mEq/Kg for 10 day s); Group D (5.0 mEq/Kg for 5 days) and Group E (5.0 mEq/Kg for 10 days). A ll lithium administrations were carried out between 14:00 and 15:00 h. Twen ty-four hours after the last oral lithium, final body weights were recorded , blood samples were obtained (by brachial vein puncture for the measuremen t of serum lithium) and the animals were sacrificed, and testes were collec ted for histological studies. Our results indicated that lithium treatment led to a significant reduction in testicular weight and seminiferous tubula r diameter, and a marked degenerative changes in germ cells in that most of the spermatids and mature spermatozoa showed necrotic changes and were slo ughed off from the seminiferous tubular epithelium. Complete desquamation a nd loss of germ cells, and their clump formation were also noted within man y seminiferous tubular lumen. Notably these adverse effects were observed w hen serum lithium levels were within the therapeutic range for human. These results confirm our earlier report on lithium's adverse effects on testicu lar function, and extend further to show that lithium indeed has a signific ant adverse effect on the histomorphology, and, thus, the function of the t estis in birds.