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1. The intestinal nerve adjacent to the colon in the domestic fowl, contains motor fibres descending from the vagal and sympathetic thoracicolumbar outflows. 2. No electrophysiological or histological evidence for the existence of motor fibres ascending from the sacral part of the central nervous system could be obtained; ascending sensory fibres, however, were readily demonstrated.
1. The ladykiller (lk) gene has been located on the sex chromosome of the fowl. It is 4.2 map units distant from the feathering rate locus (k) and 11.2 map units distant from the dwarf (dw) locus. 2. Most of the embryonic mortalities associated with this gene occurred between 3 and 4 d of incubation.
1. The relationships between length, width and height of the maturing ovarian follicle of the domestic fowl (Gallus domesticus) are shown. 2. During the rapid-growth phase (yolk deposition) of the oocyte, i.e. an increase in size from about 9 mm diameter to 35 mm diameter, there is about a 15-fold increase in its surface area. During this time the number of granulosa cells adjacent to the oocyte increases by about 5-fold. 3. The granulosa cells become flatter during the growth period of the follicle, consequently increasing their surface area adjacent to the oocyte by about 3-fold. 4. Together the change in shape of the granulosa cells and the increase in their number account for the increase in area of the granulosa layer during follicular growth. 5. Measurement of the DNA content of the granulosa layer indicated a progressive decrease in the cellular content of DNA as the follicle matures.
1. The effects of feeding diets containing 54 mg, 60 mg, 65 mg or 70 mg manganese/kg to Guinea fowls on fertility, hatchability and the occurrence of malformed embryos were studied. 2. Dietary manganese affected fertility slightly, but significantly affected hatchability and the occurrence of malformed embryos. 3. Hatchability was most significantly depressed at the lowest dietary concentration of manganese, which also caused a highly significant increase in the proportion of malformed embryos. 4. Although increasing manganese to more than 54 mg/kg improved hatchability and reduced embryonic malformations, the increase did not completely eliminate the latter condition.
1. When fowl spermatozoa were incubated at 41 degrees C with tissues from the infundibulum, magnum, isthmus, shell gland, uterovaginal junction and vagina, their motility, assessed at room temperature (20 to 25 degrees C), was maintained for 4 to 12 d. 2. The survival period was much longer for spermatozoa incubated with the tissues from the infundibulum and uterovaginal junction (with sperm-host glands, 11 to 12 d) than for those incubated with tissues from the other regions (lacking host glands, 4 to 7 d). 3. In the tissues of the infundibulum and uterovaginal junction, spermatozoa entered the sperm-host glands and were more closely associated with the epithelial cells than they were in tissues from other regions.
1. The proportions of granulosa cells containing one, two, or more nucleoli were determined in ovarian follicles of the domestic fowl (Gallus domesticus). Follicles ranged in size from 5 to 37 mm diameter. 2. The greatest proportion of cells (65%) contained one nucleolus. Cells containing two nucleoli were fewer (29%) and those containing more than two were rare (6%). 3. There was a tendency for the proportion of multinuclear cells to decrease with increasing size of the follicle. Conversely there was a similar tendency for the proportion of cells with single nucleoli to increase with size of the follicle. These relationships are curvilinear. 4. Suitable linear models confirmed these observations (P less than 0.005). 5. These results may provide an explanation for the previously reported progressive decrease in cellular DNA as the follicle increases in size.
1. A diffusion chamber technique was used in an attempt to prolong the life-span of fowl spermatozoa at 41 degrees C in vitro. 2. The most suitable conditions in the diffusion chamber system for this purpose were found to be pH 7.2, with the addition of foetal calf serum (400 mg/ml), a sperm concentration of 10 X 10(9)/ml and a gas mixture of 5% CO2 + 5% O2 + 90% N2. 3. The spermatozoa stored in the diffusion chamber under these conditions were highly fertile for at least 2 d, whereas those stored in a test tube had a low fertilizing ability.
The effects of various cryoprotectants (glycerol, dimethylsulphoxide (DMSO), methylformamide and ethylene glycol) of the same molarity on preserving the morphology of frozen and thawed fowl spermatozoa (especially midpiece and acrosome) were examined under the light (LM) and scanning electron microscope (SEM) to determine the most suitable. Under LM, the mean respective increases in sperm deformity in semen diluted with ethylene glycol, methylformamide, glycerol and DMSO were 4.5, 4.9, 5.0 and 6.5 percentage points. Under SEM, the mean respective increases in acrosomal deterioration in semen diluted with glycerol, ethylene glycol, DMSO and methylformamide were 6.6, 8.8, 13.1 and 31.2 percentage points. From these results, it appears that glycerol is superior to ethylene glycol DMSO and methylformamide as a cryoprotectant.
After preincubation of anterior pituitary glands of broiler fowls for 20 h in either medium alone or medium containing progesterone, their responsiveness to hypothalamic stimulation and to thyrotrophin releasing hormone (TRH) was determined. Following exposure to progesterone the basal rate of release of prolactin was reduced in a concentration-related manner but basal growth hormone release was unaffected. Stimulation of the release of prolactin and growth hormone by both hypothalamic extract and TRH was reduced following incubation with progesterone, and the reduction of the prolactin response to TRH was related to progesterone concentration.
The plasma concentrations of immunoreactive arginine vasotocin (AVT) were measured during oviposition and shortly before ovulation of the first egg (Cl) of a clutch. Immunoreactive AVT was determined on bentonite extracts of 0.5 ml plasma samples using the method of Rosenbloom and Fisher (1974). The R-70 antiserum used to measure AVT cross reacted with arginine vasopressin (AVP), however the fowl pituitary does not synthesise AVP. Over a period of 10 to 90 min before oviposition the plasma AVT concentration was about 20 pg/ml; during oviposition it increased four-fold. Measurements made at frequent intervals showed that plasma AVT concentration increased 5 to 6 min before oviposition, reached a peak during oviposition itself and decreased rapidly in the following 5 to 6 min. The surge in plasma AVT occurred on average 48 min before Cl ovulation.
The plasma concentration of prolactin in immature cockerels was increased between 10 and 40 min after the intravenous administration of prostaglandin (PG) F2 alpha (200 micrograms/kg body weight). Lower doses had no effect on plasma prolactin concentration. The addition of PGF2 alpha (10(-9) to 10(-6) M) to incubation media had no effect on the basal release of pituitary prolactin but reduced the release of prolactin from pituitary-hypothalamus co-incubations. The addition of noradrenaline (10(-7) M), serotonin (10(-7) M), acetylcholine (10(-6) M) or histamine (10(-6) M) to the co-incubation increased the hypothalamus-induced prolactin release, although these effects were not observed in the presence of 10(-7) M PGF2 alpha. The in vitro release of pituitary prolactin was increased by adding chicken hypothalamic extract in the presence or absence of PGF2 alpha. These results suggest a dual effect on PGF2 alpha of prolactin secretion in the fowl; its stimulation in vivo may result from a peripheral action.
The fertilising abilities of freshly-diluted and frozen and thawed fowl semen were compared by inseminating a wide range (0.2 to 1600 X 10(6] of doses of spermatozoa. These data demonstrated that there was a non-linear relationship between numbers of spermatozoa and the probability of fertilisation. It was concluded that a typical fertility trial, which assesses the percentage of fertile eggs laid by groups of hens inseminated with a fixed dose of semen, was inadequate for comparing the quality of semen samples. An alternative fertility trial is described, which involves assessing the numbers of spermatozoa required to fertilize a particular percentage of eggs laid. This modified method showed that the quality of frozen and thawed semen, in terms of its fertilising ability, was reduced to 1.6% of that of fresh semen.
The effects of high- and low-NaCl diets on body temperature, plasma osmolality, plasma electrolytes and arginine vasotocin (AVT) were studied in the domestic fowl. Body temperature as a function of time increased or decreased significantly in the high- and low-NaCl groups respectively. Plasma osmolality, sodium and chloride concentrations and AVT concentration were significantly higher in the high-NaCl adapted group. An overall significant correlation was found between body temperature and plasma sodium-to-calcium ratio (r = 0.62). These findings support the concept of an altered hypothalamic thermoregulatory set-point, induced by changes in plasma sodium-to-calcium ratio.
Plasma concentrations of corticosterone, thyroxine (T4) and triiodothyronine (T3) were measured in representative mature female domestic fowls from three housing systems: cages, covered strawyard and range. There were no between-system differences for T4 but T3 was lower in birds from range than in those from cages. Corticosterone concentrations were lower in birds from strawyards than in those from range and cages. In the strawyards there were no differences in corticosterone concentrations between normal and low-ranking hens. The latter were selected on the basis that they remained apart from the flock, were under-weight, poorly feathered and unable to feed at will. Low-ranking hens had significantly higher plasma concentrations of T3 and T4 than normal birds. This was attributed mainly to the poor feather covering of most low-ranking birds. It was concluded that, in the assessment of different housing systems, plasma corticosterone and thyroid hormones were not useful measures of long-term stress or welfare. Different factors relevant to welfare may have contrary effects on the plasma concentrations of these hormones.
In order to investigate the factors causing crooked-necked spermatozoa (CNS) or those with abnormal acrosomes during freezing and thawing, fowl spermatozoa in NaCl or glucose solutions containing 92 ml glycerol/l were examined using a scanning electron microscope before and after freezing and thawing. The incidence of CNS in NaCl solution significantly increased after freezing and thawing, but not in glucose solution. The acrosomal damage caused by freezing and thawing was considerable in both solutions, and the incidence of damage in glucose solution was significantly higher than that in NaCl solution. In neither solution was there a significant difference between the incidence of acrosomal damage in CNS and in non-CNS. The ratios of incidences of abnormal acrosome after, versus before, freezing were higher in non-CNS than in CNS. It appears from these results that the factors during freezing and thawing which cause CNS may differ from those causing acrosomal damage.
1. Studies on the egg laying pattern of the semi-domesticated helmeted guinea fowl showed that the birds laid eggs between 06.00 and 20.00 h local time (05.00 to 19.00 h GMT). 2. More (67.9%) were laid in the evenings (15.00 to 20.00 h) than at any other period. 3. There were two distinct periods in the reproductive cycle: a breeding season which began in April and ended in September, and a resting or non-breeding period between October and March. 4. Sequence length was predominantly of 4 eggs and July was the month of peak egg production.
1. Blood glucose concentration, glucose turnover and gas exchange were monitored in adult male domestic fowl at rest and during 90 min of continuous treadmill exercise. 2. During exercise oxygen consumption increased to about three times its resting value. Blood glucose concentration fell by 26% by the end of exercise. 3. Blood glucose turnover was not altered by exercise and oxidation showed only a moderate increase (35%). Glucose oxidation accounted for 23% of the total energy expenditure at rest and this value fell to 10% during exercise. At the same time the plasma free fatty acid concentration rose to three times its resting value suggesting an increased mobilisation of this substrate. 4. It is concluded that during exercise of this relatively moderate intensity glucose is a quantitatively minor fuel for the working muscles.
1. Two forms, I and II, of beta-galactosidase [EC 3.2.1.23] from fowl spermatozoa were separated by Blue-Sepharose CL-6B chromatography. 2. The two forms of the enzyme yielded different pI values (4.1 and 4.7 for form I and 5.3 for form II). 3. Their gel filtration patterns were also different: form I resolved into two peaks with Mr about 65,000 and 80,000, whereas form II resolved into a single peak with an Mr of about 65,000. 4. Both forms had similar optimum pH, pH stability, thermal stability and Km values. 5. Differences between the characteristics of beta-galactosidase forms from spermatozoa and from seminal plasma suggest that the beta-galactosidases investigated in this study are spermatozoa-specific.