Biomedical subjects
Publications and source records attributed to N Snapir.
Artificial insemination and natural mating were used for the crossbreeding of the Muscovy drake with the Pekin duck in order to produce the Mule duck. An average fertility rate of 48% was reached by artificially inseminating twice a week. In small flocks, however, when the male to female ratio was 1:2.5 (or higher), natural mating yielded a fertility rate of 80%.
An improved method for obtaining semen from the Muscovy drake using an "artificial vagina" was developed and employed on a commercial scale. With such a procedure, the ejaculate volume was 1.12 +/- .85 ml, semen concentration was 1.35 +/- .43 X 10(9) cells/ml with 8.6 +/- 6.3% abnormal sperm cells. Average spermatozoal motility was graded as 3.59 +/- .93 on a scale of 0 to 5 and the initial pH was found to be 7.30 +/- .23 within 5 min of ejaculation.
Three light sources: Cool-White (C), Vita-Lite (V), and tungsten (T), each at two intensities (20 or 50 lx), were used to supplement light to 16 hr in a 24-hr cycle for geese maintained in open-shed pens. Two lines of mixed breeds of geese, white and grey, were used and egg production was followed from the 27th week of age through 6 months of the laying period. A significant increase in egg production was found under the C light illumination. At 20 lx, egg production was significantly higher than at 50 lx. No difference in egg production was found between the two lines of geese; however, significant interactions were found between light sources, intensities, and geese lines, as exhibited by different patterns of egg production. Light intensity had the greatest effect until peak egg production had been reached; thereafter, egg production was influenced mainly by the light source.
The effect of clomiphene-citrate (CC) on broody turkey hens was examined in three experiments. Turkey hens were categorized as broody if found in the laying nest during 6 successive checks per day, if they were reluctant to leave the nest for a period of 24 hr or more, if they had ruffled feathers, and if their cloacal orifices were contracted so as to prevent vaginal exposure by abdominal massage during artificial insemination. In each experiment, 20 hens, selected as broody from commercial breeding flocks, were treated; half were treated with CC at a dosage of 6 mg/kg body weight/day (per os) for 5 consecutive days, and the rest (control) received parallel treatment with a placebo (CaCO3). In all experiments, the CC administration alleviated brooding behavior and increased egg production.
The effects of long-term injections of testosterone propionate (TP), diethylstilbestrol (DES) and TP+DES simultaneously to castrated and sham-operated White Leghorn cocks on feeding, weight gain, obesity, blood lipids and weight of various glands were studied. DES induced marked adiposity while TP reduced carcass fat content. Injections of TP+DES induced only moderate obesity. The responses of the castrated cocks to TP or DES were not always parallel to those of the sham-operated ones. In sham-operated cocks, TP induced permanent hypophagia and emaciation while in castrated cocks, although alleviating adiposity, it did not reduce the rate of weight gain and induced only a transient hypophagia. DES induced permanent hyperphagia and accelerated weight gain in sham-operated cocks while in those castrated, it induced only transient hyperphagia which later on changed into hypophagia. Although the latter cocks did not gain more weight than those castrated with no steroids supplementation, they were much more obese and had a fat content similar to that of the sham-operated ones treated with DES. The castration was found to alleviate the depressing effect of TP on adenohypophyseal and thyroidal weights. The results may suggest: (1) In the White Leghorn cocks, DES increases lipogenesis and food intake while TP results in the contrary. (2) Castration should not be considered as a lack of gonadal steroids only.
Injection of 5 microliter isotonic glucose into the third ventricle above the basal hypothalamus but not in the posterior hypothalamus-anterior midbrain, suppressed feeding in satiated cocks. This suppression of food intake was less dramatic when glucose was injected after 5 hr of food deprivation and was eliminated if 24 hr of food deprivation preceded the glucose administration. An involvement of a glucostatic mechanism in the regulation of feeding in the chicken is suggested.
Reproductive traits and histology of the adenohypophysis were studied in adult White Leghorn cockerels after surgical thyroidectomy or .1% propylthiouracil (PTU) food supplementation. Both treatments caused hypothyroidism as judged by a marked reduction in plasma thyroxine levels, a decrease in resting metabolic rate values, an increase in liver and adipose tissue weights, and a marked elevation in the alcianophilic cell population in the adenohypophysis. Both the PTU-treated and thyroidectomized birds demonstrated reduced testes and comb weights. However, although thyroidectomy was found to increase the number of PAS-positive cells in the adenohypophysis, the PTU treatment reduced them. This phenomena is discussed.
The effect of heat stress on capillary blood flow (CBF) distribution was examined in laying hens, using 15 micron microspheres, by determining CBF before and after elevating body temperature by 1-2 degrees C. No changes was evident in unfeathered metatarsal skin, although its temperature increased by 7 degrees C. Breast skin CBF change was 3.5 times larger than that of back skin. Comb CBF increase was larger than in wattles. CBF in upper respiratory tract increased proportionally to increment in respiratory frequency. Digestive system CBF was reduced by hyperthermia: the effect was pronounced in its upper organs (46% of normal) and decreased along the tract. CBF increased 4-fold in an expiratory abdominal muscle, a smaller rise occurred in a pectoral muscle and no change in a leg muscle. CBF in the tibia fell to 64% of normal. In the reproductive system, CBF fell to 58% of control level in the uterus, to 70-80% in the larger ovarian follicles and infundibulum with no significant changes in magnum and isthmus. Cerebral CBF increased during hyperthermia. Heat stress significantly reduced CBF to inner body organs, with marked differences between systems as well as within systems. Changes were more pronounced on 2 degrees C hyperthermia than on 1 degree C hyperthermia.
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1. Mature laying hens were subjected to ambient temperatures sufficient to maintain body temperature of 43 degrees C for periods of 6 to 7 h during the day (eight periods) or the night (five periods). This did not reduce total daily food consumption. 2. The effect of heat stress during the day was mostly on egg-shell quality, being adverse and significant. During the night heat stress caused a significant decrease in egg production, its effect during the day was less marked in this respect. 3. Heat stress thus seems mostly to affect the early stages of shell formation, while its effect on egg production seems to depend on the time at which it occurs in relation to ovulation. 4. These results suggest that egg production is directly affected by heat stress; prolonged heat stress probably also acts indirectly, by suppression of food intake.
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Intravenous injection of Ang II (val5 angiotensin II amide) elicited an immediate drinking response in the domestic fowl which lasted at least 20 minutes. The minimal dosage needed was 300 mug. Intracranial injection of 10 mug Ang II through cannulas implanted in the anterior diencephalon caused a significant increase in water intake. The minimal intracranial dosage of Ang II which evoked drinking was 2.5 mug. Intracranial injection of isotonic KCl inhibited the drinking response induced by intravenously injected Ang II when administered simultaneously. This suggests that drinking caused by both intravenous or intracranial injection of Ang II is activated through identical brain regions. The positive drinking response of the chicken is repeated concecutive intracranial injections of Ang II declined from the first injection through the following ones.
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.
Various dosages of monosodium glutamate (M.S.G.) were injected to 5 day old male chicks. Body weights, food intake, rate of obesity, semen production, some endocrine criteria and brain pathology were studied til 235 days post injection. All M.S.G. treated birds showed brain damage in the rotundus nuclei, and in the area located dorsolaterally to the ventromedial hypothalamic nuclei (V.M.H.). In some of the M.S.G. treated birds, additional brain regions were damaged, i.e. V.M.H., mammillary nuclei, dorsomedial anterior nuclei, ovoid nuclei, subrotundus nuclei, archistriatum and lateral forebrain bundles. Some of the M.S.G. treated birds showed marked abdominal fat deposition or low spermatozoan motility. It was impossible to attribute these changes to the dosage of M.S.G. injected. No significant differences were found in these parameters between the treated birds and the saline injected ones. When the M.S.G. treated birds were categorized on the basis of brain damage in specific sites, the following was observed: 1) Birds with V.M.H. damage accumulated significant larger amounts of fat in the abdominal adipose tissue than the rest of the M.S.G. treated birds. 2) Those M.S.G. treated birds, showing brain damage in their mammillary nuclei, produced semen of a very low spermatozoan motility rate as compared to the rest of the M.S.G. treated birds and the controls.
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