Follicular development in ovarian transplants in the domestic fowl

When the ovary was transplanted from the normal site to one near the posterior kidney on the body wall of a young bird, the ovary developed to maturity and appeared to be almost normal. However, using coloured dyes which were taken up by the yolks as bands of colour, it was established that the follicular development and ovarian organisation were upset, possibly due to the lack of a normal innervation of the ovary.     

Ontogenetic development of proline intestinal transport in the domestic fowl

1. The proline disappearance from the jejunal and ileal lumen of chickens aged from 1 day to 15 weeks were studied using a perfusion method "in vivo”.

2. A decrease in proline transport was observed from younger to older animals. The 2 intestinal segments showed different behaviours, the 1‐day and 1‐week‐old animals showed the same value in the jejunum, whereas in the ileum a progressive decrease in proline transport was observed from the first week of life.

3. The differences observed in the 2 segments could be attributed to the different rates of growth of the jejunum and ileum with age; the jejunum showed a peak of growth in the second week of life whereas the ileum showed a peak of growth in the first week. Proline transport in the jejunum decreased until the fifth week and remained constant thereafter.     

Further studies on the inheritance of the marbled chickdown phenotype of the domestic fowl.

1. An investigation was conducted among the progeny from crosses between Birchen Modern Game and Silver Sebright bantams into the inheritance of the marbled chickdown phenotype of the latter. 2. The marbled chickdown phenotype has been shown to depend upon homozygocity of both the birchen allele ER at the E-locus and the eumelanin restrictor gene Db. However, all stock used to establish this result were also homozygous for the linked eumelanin intensifier melanotic Ml and the pattern gene Pg, therefore yielding no information on the roles of Ml or Pg in the marbled chickdown phenotype. 3. Examination of the F2 generation both of chickdown and of adult plumage demonstrated the marbled chickdown to be homozygous ER (Db-Pg) with Ml dosage having an effect on adult plumage.     

Allelomimetic feeding in the domestic fowl

Groups of 6 chickens were housed singly in battery cages with food available ad libitum and their feeding activity during 9‐h days was recorded. A significant tendency for the birds to feed as a group rather than as individuals extended over the entire day; it was ascribed to interaction between the birds rather than to external influences. Implications for animal welfare are discussed.     

Acceleration of hatching in the domestic fowl

Eggs of the domestic fowl were stimulated from the 19th day of incubation until hatching by artificial clicks at one of two rates which, in the quail, have been found effective (1) in accelerating and (2) in retarding the development and hatching time of the foetus. The time at which each stimulated egg hatched was determined and compared with those of three control eggs kept in the same incubator. All four eggs were kept as far apart from each other as possible. Of the ten eggs given accelerating stimulation all hatched before the mean hatching time of the controls and nine before any of the controls. Of those given retarding stimulation seven hatched after the mean hatching time of the controls but only five after all the controls.

It is concluded that hatching can be advanced in the domestic fowl if the egg is given the appropriate stimulation, but that there is no evidence of the retardation of hatching under the conditions provided.     

Eggshell of the domestic guinea fowl

1. Physical characteristics of eggs of the domestic guinea fowl, Numida meleagris galeata, were measured and compared with those of its wild counterpart and with other birds using allometric relationships.

2. The shell thickness increased and the area density of pores decreased from the blunt to the pointed end of the egg. During incubation, shell thickness decreased, but the shell diffusive conductance to water vapour (G_H2O) remained constant.

3. Fresh egg mass (m₀), length and breadth of the egg, G_H2O and specific water vapour conductance, spG_H2O (G_H2O per g of m₀ ), were affected by the age of the laying flock.

4. Eggs of the domestic guinea fowl were bigger and heavier than eggs of the wild one.

5. Allometry showed that guinea fowl eggs differ from those of the other birds by their greater shell thickness and density of pores. However spG_H2O was normal, the thickness of the shell being compensated for by a greater density of pores for gas exchanges.     

Immunocytochemical component of endocrine cells in pancreatic islets of horses

The endocrine cell components in the pancreatic islets of the following 4 pancreatic regions of the horse were investigated by immunohistochemical methods: lobus pancreatis sinister (left lobe); lobus pancreatis dexter (right lobe); and 2 regions of Corpus pancreatis (body), the duodenal lobe which lies along the cranial duodenal flexure and descending duodenum, and the intermediate lobe which is situated around the portal vein. The islets in the left and intermediate lobes contained a central mass of glucagon cells surrounded by insulin cells, a few somatostatin cells and sporadic pancreatic polypeptide (PP) cells. On the other hand, the islets in the duodenal lobe were small in size compared with the other 3 regions, and were predominant in insulin and pancreatic polypeptide (PP) cells, but almost lacked in glucagon cells. These findings suggested that the duodenal lobe was derived from the ventral pancreatic primordium, and the left and intermediate lobes were originated from the dorsal pancreatic primordium. In the right lobe, the composition and distribution of the islet cells were almost the same as those in the left and intermediate lobes, but there were several lobules containing numerous PP cells as seen in the duodenal lobe.     

Lighting techniques for the domestic fowl

The investigation was designed to find lighting patterns for maximum performance from laying chickens. An experiment is described involving two strains of poultry and four rearing and two laying lighting treatments.

The rearing treatments were applied from day‐old to 18 weeks of age. Treatment 1 was considered to be the control and consisted of alternating periods of 6 hr light and 18 hr dark. Treatment 2 was 18 hr light and 6 hr dark from weeks 0–4 and then similar to treatment 1 from 4–18 weeks. Treatment 3 was similar to treatment 2 except that the light period was 9 instead of 6 hr from 4–18 weeks of age. Treatment 4 was similar to treatment 2 except that red instead of white light was used at the same intensity from 2–18 weeks of age.

Laying treatment A consisted of 6 hr light in each 24 hr at 18 weeks of age followed by 4 weekly increases of 45 min. light followed by weekly increases of 20 min. per week to the end of the experiment. Laying treatment B consisted of 9 hr light in each 24 hr at 18 weeks followed by weekly increases of 20 min. light per week to the end of the experiment. Birds reared on treatment 3 were not subjected to laying treatment A but all other rearing treatment groups were subjected to both laying treatments.

Within each laying treatment, rearing treatment 2 was found to be slightly later maturing, generally to have larger body and egg weights and to produce more eggs than treatment 1. Treatment 3B was earlier maturing, had larger body and egg weights and had lower egg production than treatment 2A. It is concluded that further investigation is required into the effects of constant daylengths, other than 6 hr between 4 and 18 weeks of age, on sexual maturity and production characters. Red, as opposed to white incandescent light during rearing, is found to have adverse effects on production characters.

The difference between laying treatments A and B is partly dependent on the associated rearing treatments. However, a large increase in daylength at point‐of‐lay, such as treatment B, hastens maturity and reduces egg production and egg weight compared to a more gradual increase such as treatment A.