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 testicular morphology were examined in the spotted munia (Lonchura punctulata), a seasonally breeding sub-tropical finch. Adult males were procured from natural populations during the month of August, a time when these birds begin to show seasonal reproductive maturity in an annual cycle. Both during the period of acclimation, and throughout the subsequent experimental period, the birds were maintained in an open aviary simulating natural environmental conditions. Lithium was dissolved in distilled water and was administered via the oral route by means of a commercially available stomach-tube. A total of five experimental groups were utilized. The first group (Group A) served 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 days); Group D (5.0 mEq/Kg for 5 days) and Group E (5.0 mEq/Kg for 10 days). All lithium administrations were carried out between 14:00 and 15:00h. Twenty-four hours after the last oral lithium, final body weights were recorded, blood samples were obtained (by brachial vein puncture for the measurement of serum lithium) and the animals were sacrificed, and testes were collected for histological studies. Our results indicated that lithium treatment led to a significant reduction in testicular weight and seminiferous tubular diameter, and a marked degenerative changes in germ cells in that most of the spermatids and mature spermatozoa showed necrotic changes and were sloughed off from the seminiferous tubular epithelium. Complete desquamation and loss of germ cells, and their clump formation were also noted within many seminiferous tubular lumen. Notably these adverse effects were observed when serum lithium levels were within the therapeutic range for human. These results confirm our earlier report on lithium's adverse effects on testicular function, and extend further to show that lithium indeed has a significant adverse effect on the histomorphology, and, thus, the function of the testis in birds.