The Harderian gland of
Pati duck (
Anasplatyrhynchos domesticus) was located within the orbital cavity at the ventro medial aspect. The gland was attached along with the eye ball with the help of orbital fascia (Fig 1 to 5). The Harderian gland was exposed after removal of the nasal bones. The gland was related with the medial rectus, superior and inferior oblique muscles of the eye ball. The findings of the present study was in agreement with the findings of
Slonaker (1918) in Sparrow (
Passer domesticus),
Wight et al., (1971) in domestic fowl,
Dimitrov (2012) in pheasants and
Ali et al., (2016) in Pigeon. The gland was not well developed in 0 weeks and 4 week age groups, so the oblique muscles could not establish thick attachment along the dorsal and ventral pole of the gland. The relationship between the Harderian gland and the muscles of the orbit was more prominent at 16 weeks, 24 weeks and 42 weeks of age. Ventrally one part of the gland reached the optic nerve and over lied on it.
Frahmand and Mohammadpour (2015) also reported similar findings in the adult Canadian Ostrich.
The gland was flat, oval and coma shaped with irregular borders. The gland had two surfaces
i.
e. the parietal and visceral surfaces, two borders and two blunt poles (Fig 6 and 7). The parietal surface was found convex and attached to fascia covered by nasal bones and interorbital septa of the orbit. The visceral surface was concave and it was attached loosely to the eye ball with fascia. The posterior border was smooth and it became convex in adult. Towards the dorsal aspect of the anterior border, there was a notch which divided the gland apparently into two lobes (Fig 7, 8 and 9). The notch was more pronounced at the 16 weeks, 24 weeks and 42 weeks age group. The similar result was also reported by
Indu et al., (2014) in the Harderian gland of adult white Pekin Duck. The dorsal lobe was curved towards ventral direction and smaller where as the ventral lobe was found larger (Fig 8). The lobes were not so prominent in the 0 weeks and 4 weeks age group because of the smaller size of the gland. But the lobe of the Harderian gland became more prominent along with the advancement of the age. The gland was light pink colour while freshly collected and colour became distrinct at adult (Fig 6 and 7). The arterial blood supplied by the ophthalmotemporal branch of the external ophthalmic artery and the venus drainage was by the ophthalmic vein. A slender branch of oculomotor nerve innervated the gland. Similar observations were also described by
Getty (1975) in the avian species,
Slonaker (1918) in Sparrow (
Passer domesticus),
Wight et al., (1971) in Fowl,
Altunay and Kozlu (2004) in Ostrich,
Frahmand and Mohammadpour, (2014) in Ostrich,
Kleckowska-Nawrot et al., (2014) in ostrich and
Ali et al., (2016) in pigeon.
The average length of the gland was recorded as 7.37±0.32 mm and 7.55±0.38 mm; 10.34±0.25 mm and 10.42±0.22 mm; 12.60±0.13 mm and 12.77±0.39 mm; 13.72±0.16 mm and 13.82±0.24 mm; 14.12±0.24 mm and 14.23±0.21 mm in left and right gland respectively in 0 weeks, 4 weeks, 16 weeks, 24 weeks and 42 weeks age group. The average breadth was recorded as 3.78±0.20 mm and 3.79±0.21 mm; 5.84±0.16 mm and 5.83±0.16 mm; 6.18±0.17 mm and 6.19±0.17 mm; 6.74±0.20 mm and 6.75±0.21 mm and 7.13±0.15 mm and 7.28±0.12 mm of the left and right gland respectively in 0 weeks, 4 weeks, 16 weeks, 24 weeks and 42 weeks age group. The average thickness was recorded 1.22±0.12 mm and 1.25±0.12 mm; 1.46±0.09 mm and 1.50±0.08 mm; 1.60±0.15 mm and 1.65±0.16 mm; 1.85±0.12 mm and 1.88±0.14 mm and 2.12±0.11 mm and 2.14±0.15 mm of the left and right gland respectively in 0 weeks, 4 weeks, 16 weeks, 24 weeks and 42 weeks age group. The weight of the Harderian gland of
Pati duck of 0 weeks, 4 weeks, 16 weeks, 24 weeks and 42 weeks age groups was recorded as 94.16±2.87 mg and 94.33±3.05 mg; 165.67±3.98 mg and 167.83±3.12 mg; 196.16±6.18 mg and 198.21±6.46 mg; 282.17±8.86 mg and 284.67±9.31 mg and 392.17±4.94 mg and 398.67±3.54 mg of the left and right respectively (Table 1). Findings of the present study in the adult age group were similar with the observation in adult white Pekin duck by
Indu et al., (2014). In the macrometrical study of the Harderian gland of the Canadian Ostrich by
Frahmandand Mohammadpour (2015) recorded little higher value and it might be due to species difference and higher body weight of the Ostrich.
The result reflected an ascending trend from 0 weeks age group to 42 weeks age group in all the parameters (Table 1). The Harderian gland of
Pati Duck of Assam grew slowly till it reached the adult age. There were slight difference between left and right gland in all the parameter of the gross measurement but it was statistically not significant (P>0.05).
In the present research work, a single duct was observed in the Harderian Gland of
Pati duck (
Anas platyrhynchos domesticus). The duct was emerged from the anterior border of the dorsal lobe near the notch (Fig 5 and 7).
Wight et al., (1971) also reported that the duct of the Harderian gland of fowl was single and sometimes it was pigmented. In the fowl, turkey and duck a single duct left the anterior tip of the Harderian gland to open into the conjunctival sac at the base of the nictitating membrane as reported by
Burns and Maxwell (1978). In the 0 weeks and 4 weeks it was difficult to locate and measure the duct as it was blended with the fascia. In 16 weeks, 24 weeks and 42 weeks the duct was noticeable and clearly differentiate from the fascia. The average length of the duct was recorded as 4.34±0.45 mm and 4.41±0.36 mm; 5.15±0.52 mm and 5.22±0.46 mm and 5.78±0.63 mm and 5.82±0.68 mm of the left and right Harderian gland of 16 weeks, 24 weeks and 42 weeks of age group respectively. The duct ultimately opened into the conjunctival sac at the base of the 3
rd eyelid. The present findings revealed similarity with the finding of
Payne (1992) in Fowl,
Indu et al. (2014) in white Pekin duck and
Ali et al., (2016) in pigeon.
