Influence of fowl uropygial gland and its secretory lipid components on the growth of skin surface fungi of fowl.

Fungal species, which were shown to colonize consistently on the skin surface of the breast region of adult (1 year old) white leghorn fowl, were identified as Aspergillus sydowii, A. tamarii, A. rugulosus and Absidia corymbifera. Of these, A. sydowii and A. tamarii were the dominant forms. Two species of fungi, namely, Aspergillus niger and Scopulariopsis brevicaulis were shown to be present in the cultures of the scrubbings from breast skin surface after 60 days of captivity of the fowls. Extirpation of the uropygial gland resulted in encouragement of the in vitro population growth of all species of fungi except that of A. rugulosus. The effect was found to be very conspicuous for A. sydowii and A. tamarii, particularly after 60 days of gland removal. Addition of total lipids and the wax diester component of free-flowing uropygial secretion as 0.2% suspension in Sabouraud's agar medium of individual fungal isolates caused marked suppression of the population growth of A. sydowii, A. tamarii, Absidia corymbifera and to some extent of S. brevicaulis. Other components of secretory lipids, such as wax alcohols (2,3-alkane-diols), wax acids, triglycerides and hydrocarbons (including squalene) when supplemented separately to culture medium of individual fungi at identical concentration, were also shown to cause inhibition of the growth of most of fungal species at different degrees.

Influence of fowl uropygial gland and its secretory lipid components on growth of skin surface bacteria of fowl.

Bacterial species, which occur on the breast skin surface of adult (1 year old) white leghorn fowl with intact uropygial gland, were identified as : Staphylococcus epidermidis, Sarcina lutea, Streptomyces sp. and a facultative diphtheroid belonging to the genus Corynebacterium; S. epidermidis being the most predominant one. Two species of bacteria, namely, Staphylococcus aureus and Proteus sp. were shown to colonize the skin surface after 60 days of captivity. Extirpation of uropygial gland caused severe depletion of population of S. epidermidis, Streptomyces sp. and diphtheroid. The effect was more conspicuous after 60 days compared to that after 30 days of the gland removal. On the skin surface of glandless fowls the population of S. aureus increased significantly and a new form identified as anthracoid bacillus became the most predominant species after 60 days. Addition of total lipids from the free-flowing fowl uropygial secretion, as 0.2% suspension, to trypticase soya broth cultures of individual bacteria of fowl skin surface encouraged strongly the growth of S. epidermidis, Streptomyces sp. and Proteus sp. but suppressed the population of the anthracoid. When identical amount of diester wax or wax alcohol of the secretion was supplemented to the culture, more or less similar result was obtained. Wax alcohol also had a mild inhibitory effect on Streptomyces sp. Wax acids, added to the culture (0.2%) suppressed population of all the bacterial forms except Proteus sp., while the hydrocarbon fraction, which also contained some amount of squalene, produce an opposite effect.

Adrenocortical influence on histokinetics and lipid components of uropygial gland of immature chick.

Adrenocortical influence on uropygial gland of 10-day old male white leghorn chicken was assessed by suppressing glucocorticoid level with metyrapone and following corticosterone and deoxycorticosterone acetate (DOC) treatments (im), 100 micrograms each on alternate day for a period of 15 days. Metyrapone treatment resulted in significant atrophy of the uropygial gland with a severe regression of the glandular alveoli due to cytopycnosis, cellular disintegration and drastic cell loss. Concomitantly, there was a depletion of glandular lipid and its diester wax fraction. Corticosterone, administered simultaneously with metyrapone, counteracted severe adverse effects of the latter on the uropygial gland. In the normal chicken also corticosterone alone caused glandular hypertrophy with increased rate of cell renewal and cell growth within the alveoli and, to a lesser extent, augmented output of the glandular lipids. Simultaneous administration of corticosterone and testosterone propionate (TP), on the other hand, caused a moderate suppressive influence on this gland. DOC treatment alone or with metyrapone and TP failed to exert any noteworthy change in the uropygial gland excepting a moderate reduction of gland weight and a rise of glandular lipids observed after combined injections of DOC with TP and with metyrapone respectively.

Effect of glucose on the activity of feeding centres before and after parasagittal cuts between medial and lateral hypothalamus.

Intracarotid administration of isotonic glucose (0.5 ml of 5.4%) in the starving albino rats produced an increase in the multiunit activity (MUA) of ventromedial hypothalamus (satiety centre) and a decrease in the MUA of the lateral hypothalamic area (feeding centre). Intracarotid infusion of normal saline did not change the MUA of any of these centres. Parasagittal knife cuts placed in between the satiety and feeding centres did not affect the responsiveness of these centres to glucose administration as indicated by the recorded multiunit activity.