Evaluation of putative appetite suppressants in the domestic fowl (Gallus domesticus)

1. The effectiveness of the appetite suppressants fenflur‐amine, furanone and crotonolactone were evaluated in a series of experiments with adult male layers and growing broilers of both sexes fed on diets with concentrations of up to 1000 mg/kg.

2. Fenfluramine produced a curvilinear decrease in food intake and body weight in adult layers and growing broilers.

3. Inconsistent responses to furanone and crotonolactone were obtained with adult layers and broilers in cages, but a similar decrease in food intake and body weight for both drugs was recorded in male broilers raised in floor pens.

4. The responses to subcutaneous injection of 20 mg/kg of each drug on food intake over 24 h were comparable to those for dietary inclusion. Fenfluramine, however, produced a greater response in male compared with female broilers and induced signs of hyper‐thermia in broilers and layers.

5. Subcutaneous injection of 50 mg crotonolactone/kg was associated with decreases in the food intakes of 4 strains and there was evidence of different responses between lines.

6. It was concluded that none of the drugs used were likely to be suitable for the control of food intake in broiler breeder flocks.     

Experimental stimulation of eosinophil production in the domestic fowl (Gallus gallus domesticus)

A method has been devised to produce eosinophilia in birds experimentally. Multiple intraperitoneal injections of bovine serum albumin (BSA) produced a greater response than horse serum in young adult fowls, and injections of 2 ml BSA were more effective than injections of 0.2 ml. The highest eosinophilic responses were obtained with injections of BSA together with aluminium hydroxide. Thymectomy had little effect on eosinophil numbers following horse serum injections but irradiation produced a depressed response. Horse serum that had been heated to 56 degrees C for 30 minutes to inactivate complement and to denature proteins, including possible horse IgE, induced an eosinophilic response in 50 per cent of birds compared with only 14 per cent with unheated horse serum. Furthermore, when the former birds were reinjected after a rest period of 13 weeks, the eosinophilic response followed a similar curve as before but a higher proportion of birds responded. Birds aged over two years did not give a good eosinophilic response after horse serum stimulation. There was no consistent correlation between raised IgE levels and eosinophil numbers. Tolerance to horse serum was detected in some birds using a radial immunodiffusion technique. Analyses of blood plasma from birds with eosinophilia showed a significant increase in total amino acids compared with normal birds.     

Spectral sensitivity of the domestic fowl (Gallus g. domesticus).

1. The spectral sensitivity of 7 broiler fowl was determined in a behavioural test. 2. Initially the birds were trained to receive a food reward by pecking at a clear, Perspex panel behind which was a light stimulus (circular, diameter = 9 mm), originating from a tungsten-halogen lamp. Subsequently, they were trained to choose between 2 panels only 1 of which was lit; the assignation of light and dark on each panel was randomly ascribed between trials. The colour of the lit panel was determined by the wavelength of the light transmitted through one of 13 closely defined narrow bandwidth filters between 326相似文献   

The effects of progesterone on oviposition and ovulation in the domestic fowl (Gallus domesticus)

1. Following an injection of 0.5 or 0.1 mg progesterone/kg between 0 and 6 h after ovulation, oviposition of the resulting egg was delayed by 1 to 11 h and occurred 26 to 31 h after injection, depending on the dose. The injection terminated the laying of a sequence of eggs by causing the next ovulation to occur a day late. The delayed ovulation occurred at the time normally expected for the first ovulation of a sequence and became the first of a new sequence.

2. Following an injection of 0.5 or (H mg progesterone/kg between 6 and 15 h after ovulation, oviposition of the resulting egg was generally delayed by between 15 and 28 h and occurred at the same time of day as the next ovulation, which was delayed as in the first experimental situation. Subsequent ovulations were resynchronised and followed at intervals according to the normal sequence established before the injection.

3. Injection of 0.5, 0.1 or 0.05 mg progesterone/kg between 12 and 9 h before an expected ovulation advanced the oviposition of the egg already in the uterus (shell gland) by about 3 h. The succeeding ovulation was either advanced or blocked.

4. These observations suggest that the pre‐ovulatory surge of progesterone is directly or indirectly involved in the timing of oviposition and ovulation.     

Discrimination between individual humans by domestic fowl (Gallus gallus domesticus).

1. We demonstrate that Barred-Rock and Isa-Brown hens can discriminate between the presence of 2 different humans and use this information as a cue for whether or not to make an operant response. 2. This demonstration in domestic fowl, the first of its kind in any avian subject, is consistent with a growing body of evidence that many species, including agricultural animals, are surprisingly adept at differentiating between humans. 3. Such a discriminative ability carries considerable implications for issues related to husbandry, production and welfare.     

Bilateral testicular asymmetry and supernumerary testes in the domestic fowl (Gallus domesticus).

1. The left and right testis weights from 378 males in 7 experiments were recorded. 2. The relationship between the right and left testis weights was similar in males of different ages, strains and body weights. 3. The left as a proportion of total testes weight was approximately normally distributed about a mean of 0.515. 4. The left testis was greater than the right testis weight in 0.67 of males. 5. The linear regression of the natural logarithm of the right on that of the left testis weights was -0.04 + 0.99X (r2 = 0.98) and it was concluded that, in general, the left and right testes were of similar weight. 6. Three cases of triorchidism (two left testes) occurred, suggesting that this may not be a rare condition in the domestic fowl.     

Utilisation of energy substrates in treadmill-exercised domestic fowl (Gallus gallus domesticus): blood glucose

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.     

Probable occurrence of IgE in the adult domestic fowl (Gallus domesticus) after horse serum stimulation

Radioimmunosorbent techniques using antisera to human immunoglobulin E (IgE) showed the presence of high levels (up to 15,840 U/ml) of IgE in serum and plásma from fowls immunised by repeated intraperitoneal injections of horse serum. These results were confirmed by passive cutaneous anaphylaxis and heat lability tests.     

Patterns of cell proliferation and growth rate in limb bones of the domestic fowl (Gallus domesticus)

The growth rates of each extremity of the tibiotarsus (TibT) and tarsometatarsus (TMT) bones and of a phalangeal bone were measured in Rhode Island red chicks. Histological sections of the growth plates at each of these sites were made for measurements of the thickness of the flattened dividing cell layer and counts of the number of cells between its boundaries. The diameter of the mature chondrocytes in the metaphysis was also measured. The extent of the dividing cell population within the flattened cell layer and the proportion of cells in division were measured from autoradiographs prepared after labelling dividing cells in vitro or in vivo (three birds in each group) with tritiated thymidine. From the results the rate of cell production in the plane of growth at each growth plate was estimated. It varied from about six cells per day at each end of the phalanx to just over 50 cells per day at the proximal end of the TibT and TMT. The duration of the cycle time was estimated to be 13 to 21 hours at the proximal TibT and TMT and distal TibT but considerably longer at the distal TMT and at both ends of the phalanx. Variation in growth rate between extremities of the bones examined was associated largely with variation in the dividing cell populations and the thickness of the flattened cell layer, but it appears that there were also significant differences in cell cycle times between sites. The in vitro and in vivo labelling techniques gave comparable results.     

Changes in the collodiaphyseal angle with growth in the fowl (Gallus domesticus)

The angle formed between the femoral neck and shaft is referred to as the collodiaphyseal angle. In man, the angle decreases during growth and is frequently different in the right and left limbs. This study examines the collodiaphyseal angle in another biped, the growing fowl. Three groups (A, B and C) of growing fowls were examined. The weight difference between birds would alter the forces applied to the growing proximal femur and at the end of the experimental period the birds in group B weighted three times those in group A. Nevertheless, in all three groups the collodiaphyseal angle decreased from 120 degrees to 108 degrees over the growth period. Where there was a difference in collodiaphyseal angle between right and left limbs the angle was more frequently greater in the right. Bodyweight apparently had little effect on the development of collodiaphyseal angle in the fowl, possibly due to the trocharteric/antitrocharteric articulation reducing the stresses applied to the femoral neck.     

Utilisation of energy substrates in treadmill-exercised domestic fowl (Gallus gallus domesticus): blood plasma free fatty acids

1. Plasma free fatty acid (FFA) concentration, FFA turnover and gas exchange were measured in adult male domestic fowl at rest and during 90 min continuous treadmill exercise at a work load of approximately three times the resting metabolic rate. 2. Plasma FFA concentration and turnover increased 7-fold and 4-fold respectively during exercise. Of the FFA turnover 0.54 was oxidised at rest and this increased to 0.70 during exercise. The fraction of the total carbon dioxide production derived from plasma FFA oxidation rose from 0.33 at rest to 0.55 during exercise. 3. It is concluded that plasma FFA are the most important source of energy for the working muscles of domestic fowl during treadmill exercise of this intensity and duration.     

Effect of administering two prostaglandin synthetase inhibitors (indomethacin and aspirin) on egg production in the domestic fowl (Gallus domesticus)

The injection of 50 mg/kg bodyweight of a prostaglandin synthetase inhibitor (indomethacin) brought about a delayed oviposition time in birds of three breeds of layers, whereas the injection of 5 mg indomethacin had no effect. The daily ingestion of up to 400 mg aspirin or up to 10 mg indomethacin for three weeks, or 750 mg aspirin or 200 mg indomethacin for two weeks had no effect on egg production, oviposition time, egg-shell water conductance, oviducal prostaglandin synthetase activity or bird behaviour. Prostaglandin synthetase activity was demonstrable in both control and treated birds only in the tubular glands of the shell gland. These observations suggest that prostaglandins play a minor role in normal reproductive activity in the female domestic fowl.     

Active spermiophagy in the initial part of the proximal efferent duct of the epididymis of normal domestic fowl (Gallus domesticus)

In a study of the absorptive activities of the excurrent ducts of the testis of birds, six adult cocks of the Ovambo breed of domestic fowl were deeply anaesthetised and intravascularly perfused with buffered 3 per cent glutaraldehyde. Epididymal tissue was prepared conventionally for electron microscopy. In favourable sections in three of these birds avid ingestion of spermatozoa was revealed in the non-ciliated (Type I) cells of the epithelial lining of the initial part of the proximal efferent duct, at and a little beyond its junction with the rete testis. No obvious defects were detected in luminal spermatozoa. The testicular excurrent ducts were neither distended nor obstructed, and mononuclear cell mobilisation was absent in both the ductal and periductal tissue. The significance of this observation with regard to the specific segment of the efferent duct system involved and how certain spermatozoa are identified for elimination from the duct lumen, must await precise studies.     

Further observations on functional deletion of paraocular glands in the fowl (Gallus domesticus)

Methods are described for inoculation of the fowl Harderian gland with sclerosing reagent and for its surgical excision. Though very destructive the former procedure proved the less reliable in achieving the gland's complete functional deletion. Three weeks after surgical removal of the Harderian glands the lachrymal glands of 10-week-old fowls were heavier and contained more immunocompetent cells than the glands of intact and sham operated birds. When adult birds deprived of both paraocular glands were given sheep erythrocytes or Newcastle disease virus by eye drop they developed slightly higher than normal titres of serum antibody but failed to produce lachrymal antibody.     

Histochemical identification of tissue eosinophils in the inflammatory response of the fowl (Gallus domesticus)

A staining technique was developed for the differential identification of tissue eosinophil and heterophil leucocytes in the fowl. Pieces of formalin-fixed skin, challenged with dinitrochlorobenzene (DNCB) or citraconic anhydride (CA), were incubated in a substrate suitable for peroxidase prior to embedding in either paraffin wax, glycol methacrylate or Araldite. This results in deep brown staining of the eosinophil granules while those of the heterophils remain unstained. Heterophils and eosinophils were conspicuous at 30 minutes after challenge in the early inflammatory response. By 48 hours the heterophilic response had diminished and eosinophils had almost disappeared. Only mononuclear cells were seen at 72 hours. It is suggested that the eosinophil leucocyte might act as an early modulator of inflammation in delayed-type hypersensitivity responses in the fowl.