Z. U. Rahman

Somatotrophs and lactotrophs: ' an immunohistochemical study of Gallus domesticus pituitary gland at different stages of induced moult

The objective of this study was to determine the distribution of somatotrophs and lactotrophs and conduct a morphometrical analysis of immunoreactive somatotrophs and lactotrophs in the pituitary glands of White Leghorn Hens (Gallus domesticus) during the period of induced moult. We divided the periods of induced moulting into three phases viz. 7, 14 and 21 days. The labeled alkalinephsphatase method with anti-GH (growth hormone) and anti-PRL (prolactin) as a primary antibody was used to detect somatotrophs and lactotrophs, in the midsagital sections of chicken adenohypophysis. Immunohistochemistry showed that somatotrophs are not only confined to the cephalo-caudal axis but can also be found in the caudal lobe; while lactotrophs were distributed in both lobes of the anterior pituitary gland at all stages of moulting (7, 14 and 21 days). Lactotrophs were of different shapes but somatotrophs were oval to round in morphology. At the given stages of induced moulting, some hypertrophied lactotrophs were also present after 7 days of induced moult in the anterior pituitary gland. However, there were moulting-related changes: from 7 to 21 days of induced moulting the immunoreactive-PRL cell population decreased, while the mean lactotroph size was more than that of somatotrophs. Basic quantitative and morphological information relating to somatotrophs and lactotrophs during the period of induced moult in laying hens is reported here and the changes brought about by induced moulting are restricted to PRL positive cells rather than GH positive cells.

Comparison of the fast-induced and high dietary zinc-induced molting: trace elements dynamic in serum and eggs at different production stages in hens (Gallus domesticus)

A number of 252, 70 week old, single comb white leghorn hens at the end of their first production cycle were divided into two groups: group-I; molted by fasting and group-II; by high dietary zinc to obtain the second and third production cycle. Sampling was carried out at 5%, peak and end of the second production cycle and at 5% and peak of the third production cycle. Serum zinc decreased at the peak of the second production cycle, while increased at the 5% of the third production cycle in zinc-molted group. Serum copper and manganese increased at the 5% and peak of the second production cycle in zinc-molted group. Egg albumin zinc and copper increased at the 5% and peak of the second as well as third production cycles in zinc-molted group. Egg albumin manganese increased at 5% during the second production cycle in fasting molted group. Egg yolk zinc increased at the peak of the second production cycle in zinc-molted group. Egg yolk copper increased at the 5% of second production cycle but decreased during the third production cycle in zinc-molted group. Egg yolk manganese increased at the 5% and at the end of the second production cycle in zinc molted group. Egg yolk manganese and iron decreased during the third production cycle in zinc-molted group. Eggshell zinc decreased at the end of the second production cycle in the zinc-molted group, while eggshell copper increased at the peak of the second as well as third production cycles in fasting molted group.

Immunohistochemical localization and morphometry of somatotrophs and lactotrophs in protein, probiotic and symbiotic supplemented molted layers

Two hundred Single Comb White Leg-Horn spent hens at the age of 70 weeks were purchased from a commercial layer farm. The birds were shifted to the Poultry Research Station, Department of Physiology and Pharmacology, University of Agriculture, Faisalabad, Pakistan. High dietary zinc (3 g/kg feed/day) was used to induce molting in all the birds after one week of acclimatization. Thereafter, birds were divided in groups of 50 birds each, with the following treatments: G1 [control; crude protein (CP)16%, no other supplement], G2 (CP18%, no other supplement), G3 (CP16%, Symbiotic, 85 mg/L drinking water) and G4 (CP16%, Probiotic, 85 mg/L in drinking water). Fifteen birds were slaughtered at 5% of peak of production for each group to collect their pituitary glands. Better egg production was seen in all the supplemented groups as compared to the control. Especially an earlier post molt production recovery and delayed decline was seen in G2 as compared to all other groups. The immunohistochemistry of the pituitary gland reveals the decrease (P≤0.01) in the cell and nucleus size as well as area of somatotrophs in G2 and G4 as compared to G1. The cell and nucleus size as well as area of lactotrophs decreased (P≤0.01) in G2, G3 and G4 as compared to G1. The better and earlier post molt production in G2 highlights the potential role of protein supplementation in connection with the decreased lactotroph size and area in molted birds.

Immune potentiating role of protein, probiotic and symbiotic supplementation in moulted White Leghorn hens

This study investigated the effects of high protein, probiotic and symbiotic supplementation on the immunity of culled moulted White Leghorn hens. Cage-housed hens (n = 240) aged about 70 weeks were moulted by including zinc in the diet. The moulted hens were randomly divided in four treatment groups: control group (G1; CP 16% in basal diet), high protein group (G2; CP 18% in basal diet), probiotic supplemented group (G3; symbiotic at a dose rate of 85 mg L−1 in drinking water + CP 16% in basal diet), and symbiotic group (G4; probiotic at a dose rate of 85 mg L−1 in drinking water + CP 16% in basal diet). Ten birds from each group were euthanised at 5% peak (5P), full peak (FP), and end of production (EP). Blood samples were taken for serum to estimate geometric mean antibody titre (GMT) against Newcastle disease virus (NDV) and egg drop syndrome (EDS) virus. Macrophages were isolated from abdominal exudates (AE) to observe their engulfment response and their nitric oxide (NO) production. 2,4-Dinitrochlorobenzene (DNCB) was inoculated on the skin of five birds in each group to evaluate the delayed type hypersensitivity response by determining the skin thickness. The overall humoral antibody GMT against NDV in the groups was higher in G2, G3 and G3 compared to G1. GMT value against EDS was higher in G2 compared to G1. A significant increase (P ≤ 0.01) in macrophage engulfment and NO production was seen in G2 and G4 compared to the G1. The DNCB inoculated skin thickness response remained higher (P ≤ 0.01) in G2 until FP than the other groups. A diet rich in protein or supplemented with a probiotic or a symbiotic enhances the body immunity of moulted hens.

Changes in luteinizing hormone-containing gonadotrophs after moulting induced by fasting and zinc in laying hens (Gallus domesticus)

The purpose of the present study was to investigate egg production performance, immunohistochemical (IHC) identification, localization and morphological characterization of moulted hens pars distalis luteinizing hormone (LH) gonadotrophs. This system has been validated for chicken LH by immunodetection of purified hormones on dot blots, western blotting and by specific labelling of cells on sagittal sections of chicken pituitaries. This study showed that egg production and egg weight increased significantly after zinc-induced moult when compared with fasting-induced moult. Luteinizing hormone-gonadotrophs are of numerous shapes and distributed throughout the adenohypophysis, with densely populated regions on the margins of pars distalis. Moulting of laying hens was associated with a significant increase in immunoreactive LH gonadotroph cell count and cell size, which peaked at the subsequent production stages. Zinc-induced moulting also caused a significant increase in LH gonadotroph cell size as compared with fasting-induced moulting. The nuclear size of LH-positive cells was distinct during decreased egg production. Our results validate the use of ovine LHbeta antibodies for the IHC localization of chicken LH gonadotrophs. This technology was further applied to the characterization of the shape and morphological changes of gonadotrophs as a function of the egg production status of the birds.

Dermatotoxic effects of orally administered ciprofloxacin in sweating and nonsweating animal models

Context: Some drugs, such as ciprofloxacin (CFX), that are excreted in sweat may produce some effects/toxicities in the skin structure. In order to differentiate the dermatotoxic effects of drugs due to excretion in sweat, it is essential to perform simultaneous studies in sweating and nonsweating animal models. Objective: To determine the dermatotoxic effects of CFX in sweating (goats) and nonsweating (rabbits) animals and to determine whether there is a relationship between dermatotoxicity and the blood CFX concentration. Materials and methods: CFX was administered orally at the dose rate of 20 mg/kg body weight to goats (n = 16) and rabbits (n = 16) for 1 and 2 weeks, while control animals were given vehicle (water). Skin biopsies were taken after 1- and 2-week administration of CFX and processed histologically. Similarly, the CFX concentration in the plasma samples was analyzed by high-performance liquid chromatography (HPLC). Results: Mean ± standard error (SE) epidermal thickness (μm) was 26.2 ± 0.2, 38.6 ± 2.05, and 37.8 ± 1.8 for the control, 1-week-treated, and 2-week-treated goats and 16.06 ± 2.39, 50.67 ± 6.61, and 34.03 ± 4.12 for the control, 1-week-treated, and 2-week-treated rabbits, respectively. Mean ± SE epidermal cell layers were 2.08 ± 0.08, 3.42 ± 0.16, and 3.25 ± 0.21 in the control, 1-week-treated, and 2-week-treated goats and 1 ± 0, 3.08 ± 0.37, and 1.83 ± 0.35 in the control, 1-week-treated, and 2-week-treated rabbits, respectively. Mean ± SE plasma concentration (μg/mL) of CFX was 0.37 ± 0.06 and 0.30 ± 0.05 in the 1- and 2-week-treated goats and 0.13 ± 0.04 and 0.14 ± 0.09 in the 1- and 2-week-treated rabbits, respectively. Conclusion: Microscopically, increases in epidermal thickness, number of cell layers, and cell infiltration were observed in both sweating and nonsweating animals, indicating that the dermatotoxic effects may not be due to CFX excretion in sweat. No relationship was found between dermatotoxicity and blood CFX concentration in both animal models.