Abstract:
Mammalian pineal gland, an integral part of brain, is a photo-neuroendocrine gland which controls the circadian rhythms and reproductive activity in seasonal breeders. This study was designed to evaluate the gross morphological and histological changes in pineal gland and plasma melatonin profile of Beetal goat in relation to different age groups. For this purpose, a total of 24 healthy female Beetal goats were selected from the local abattoir of Faisalabad and were divided into three age groups naming, prepubertal, pubertal and postpubertal (n=8). Before slaughtering, 10 ml blood was collected in EDTA coated tubes for determination of plasma melatonin level using ELISA kit. After slaughtering, heads of the animals were dissected, pineal gland was enucleated and gross morphometric measurements of the gland were taken. For light microscopic studies, the pineal tissues were fixed in a solution of 10% neutral buffered formalin and processed by the routine tissue paraffin sectioning technique. The tissue sections were stained with Hematoxylin and Eosin, modified von Kossa stain and toluidine blue. The results revealed that age of the animals has a significant effect (P=0.05) on gross anatomical parameters of pineal gland (weight, length, width and volume) as well as histomorphometric parameters including number and volume of pinealocytes, relative area of parenchyma, brain sand, connective tissue and blood vessels of the pineal gland. Age also affected the plasma melatonin level and was found significantly highest (5.63±0.20 pg/ml) in the pubertal group. In conclusion, the present study revealed that age influences the gross and histomorphology along with plasma melatonin level of the Beetal goat.