M. Perek

The effect of short heat stress upon leucocyte count, plasma corticosterone level, plasma and leucocyte ascorbic acid content

Cocks were exposed to 1 or 2 h at 24 degrees C; blood samples were taken before and immediately after treatment and for a period of 20 h thereafter. 2. Heat caused a significant decrease in leucocyte counts, an increase in corticosterone concentration in plasma and an increase of ascorbic acid in plasma and in leucocytes. 3. These four measures can be used to indicate a stress response and the measurements can be done without harming the animal.

The effect of light wavelength on the production and quality of eggs of the domestic hen

Abstract The effect of light color on egg-laying and on egg quality during the first 50 wk of egg production and during a second cycle of 19 wk following molting was examined. Hens were exposed to one of the following six sources of light: blue (B), green (G), red (R), tungsten (T), cool-white (C) fluorescent or simulated-sunlight (V) fluorescent tubes. Light intensity was equalized at photon output. Total egg production per hen was significantly influenced by the color of light with the most eggs being procuced in R light and the fewest in B light. Hens were more sensitive to light color in response to egg production during the second cycle than during the first cycle. Hens in C light produced significantly fewer eggs than those under V light in both laying cycles. Eggs laid under B or G light were consistently larger than those under R light. Egg weights of hens in V light were heavier than those for the C or T light groups. In the first cycle, shell quality was significantly better in G light than in B or R light. Percent of yolk increased and percent of albumen decreased with age during the first cycle in all treatments and the rate of change was directly related to light color (wavelength). In the second cycle, shell quality, percent of shell, yolk and albumen did not change significantly with age in any of the light treatments. It can be concluded that the wavelength of light may influence egg production, egg components and shell quality of the domestic laying hen.

Short heat stress as an immunostimulant in chicks

The effect of 1 hour exposure of seven 1-week-old chicks to heat stress (41.5-42.5 degrees ) on their antibody titre after antigenic stimulation with E.coli bacteria was assessed. Exposure to heat 24 or 96 hours after immunisation resulted in a significant increase in antibody titres while heat treatment 42 or 72 hours after vaccination caused a non-significant increase in antibody titres. Heat exposure for 2 hours, 24, 48, 72 or 96 hours after immunisation either with E. coli or sheep red cells (SRBC) resulted in significantly increased antibody titres. When a number of antibody forming cells (against SRBC) in the spleens were tested, heat treated chicks showed no significant increase compared with the non-treated group. Heat-exposed chicks phagocytised Staphylococcus aureus bacteria (as measured by their disappearance from the blood) more rapidly than the non-treated group.

Removal of olfactory bulbs in chickens: Consequent changes in food intake and thyroid activity

Surgical removal of the olfactory bulbs (O.B) in the chicken caused a marked increase in food intake, which was not accompanied by development of obestiy. Oxygen consumption of the O.B. removed birds was significantly higher than that of the controls. Alcianophylic-thyrotropic cell population of the adenohypophysis and the percentage of active follicles in the thyroid gland were higher for the O.B. removed birds than for those of the controls. Feed supplementation of 0.1% propylthiouracil to the O.B removed birds abolished the previously exhibited hyperphagia and caused a significant decline in oxygen consumption. The possibility that the O.B removal caused a primary increase in thyrotropic axis activity follwoed by a secondary compensatory hyperphagia, is discussed.

The interrelationship between the olfactory bulbs and the basomedial hypothalamus in controlling food intake, obesity and endocrine functions in the chicken

Surgical removal of the olfactory bulbs (OB) in the chicken indicated an increase in thyrotropic activity followed by a compensatory increase in food intake, as shown earlier. Basomedial hypothalamic (BMH) lesions in these birds caused changes in certain parameters which strongly infer hypoactivity of the thyrotropic axis. The lesions also caused development of typical hypothalamic obesity demonstrating both dynamic and static phases. Removal of the OB in BMH lesioned birds in their static phase of obesity, caused no demonstrable physiological changes. While removal of the OB caused an increase in somatotropic activity, the opposite was found in BMH lesioned birds. Those animals in which OB were removed and BMH was destroyed, demonstrated a decrease in somatotropic activity. It is suggested that the syndrome caused by BMH lesions dominates that caused by removal of the OB. The possibility of involvement of the OB in the control of thyrotropic and somatotropic activities mediated by the basomedial hypothalamus, is discussed.

Involvement of the medial hypothalamus and the septal area in the control of food intake and body weight in geese.

Intracranial injections of 6-OHDA were used to destroy the following brain areas of male geese: bilateral VMH-mamillary (BL-VMH), unilateral VMH (UL-VMH), septal area, and bilateral hypothalamic areas located dorsal, lateral, caudal and rostral to the VMH. The brain damage was nonspecific, destroying cell bodies as well as axons. The effects of these lesions were determined on food intake, body weight, abdominal adipose tissue, liver weight and fat content, and on selected endocrine gland weights. The highest food intake, obesity and liver weight and its fat content were exhibited by the BL-VMH lesioned geese. The UL-VMH and the septal lesioned geese showed moderate increase in food intake, which eventually decreased in the UL-VMH but remained constant in the septal lesioned ones. The liver fat content of the latter groups of geese was higher than the controls. No differences were found between the controls and the group of geese lesioned in the various hypothalamic areas - excluding the VMH - in all parameters measured. While no significant differences were found in pituitary, thyroid and adrenal weights among all groups of geese, a decrease in testes weight was noted in the lesioned groups of geese as compared to the controls. The interrelationships between body weight, food intake, adiposity and liver weight are discussed.

Plasma testosterone in functionally castrated cockerels with hypothalamic lesions 1

Synopsis Two types of modified cockerels were produced by lesioning the hypothalamus: (1) functionally castrated, obese, with atrophied testes and combs, bearing lesions in the mammillary nuclei and posterior part of the ventromedial nuclei (FC) and (2) functionally castrated, obese, with atrophied testes, but with large combs, bearing lesions in the posterior part of the mammillary nuclei and part of the arcuate nuclei (FCLC). Semen could not be obtained from either type of bird. Plasma testosterone concentrations, determined by radio‐immunoassay, were 25.5 ± 5, 125 ± 20 and 508 ± 272 ng/100 ml plasma, for the FC, FCLC and control birds respectively. Correlations were not found between comb weight and testosterone concentration within each of the different groups. Neuroendocrine aspects and some physiological effects of androgenic activity are discussed in the light of previous studies with similarly lesioned cockerels.

The effect of intrahypothalamic administration of sodium pentobarbital on eating behaviour and feed intake in chickens

Abstract Injection of sodium pentobarbital solutions were carried out in chickens, through permanently implanted cannulas in the brain. Chickens with cannulas implanted in the third ventricle, above the hypothalamic ventromedial area, responded with immediate increase in feed intake and vigorous pecking behaviour which lasted from 10–60 min. Chickens with cannulas implanted in the posterior lateral hypothalamus showed no changes in their feed intake or eating behaviour after sodium pentobarbital injection. The results with chickens correspond to those obtained with rats, cats and dogs.

Histological changes in the adenohypophysis and thyroid gland of propylthiouracil-treated chickens following placement of basomedial hypothalamic lesions

Abstract Placement of basomedial hypothalamic lesions in chickens prevented hypertrophy of the thyroid gland and the increase in the population of alcianophilic-thyrotropic cells in the adenohypophysis induced by feed supplementation of 0.1% propylthiouracil. It is suggested that destruction of the basomedial hypothalamus causes damage in a possible production site of the thyrotropic releasing hormone, or, perhaps, in its transport pathway.

Evidence for enzymes of steroid metabolism in the bursa of fabricus

Abstract 1. 1. In vitro bioconversion of C-19 and C-21 steroid substrates to various metabolites by 800 g supernatant prepared from bursa of Fabricius excised from Leghorn males indicates that this tissue is capable of metabolizing steroids rapidly. 2. 2. The activity of 20α-steroid dehydrogenase appeared high as compared with that of 17β-(testosterone) dehydrogenase or Δ 4 -steroid 17–20-lyase. 3. 3. Conversely, the 19-hydroxylating and aromatizing activities for Δ 4 -androstenedione and testosterone, as well as 3β-hydroxysteroid dehydroxysteroid dehydrogenase and Δ 5-4 -ketosteroid isomerase systems for dehydroepiandrosterone, were not detected.