Variation in egg yolk cholesterol concentration between and within breeds of the domestic fowl.

1. The pattern of variation for egg yolk cholesterol concentration between 5 commercial egg layer lines and a cross of Gallus domesticus is described. 2. Yolk cholesterol concentration in the cross was lower than in the lines, and 6.7% lower than the midparent value. 3. It is proposed that the reduced yolk cholesterol concentration of the cross may be a consequence of heterosis, although sex-linkage and/or maternal effects cannot be discounted. 4. The difference between the cross and parental lines is consistent with a physiological relationship between yolk cholesterol concentration and rate of egg production, but not between yolk cholesterol concentration and yolk weight.     

Changes in the plasma concentration of immunoreactive arginine vasotocin during oviposition in the domestic fowl

1. 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.

2. 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.

3. 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.

4. The surge in plasma AVT occurred on average 48 min before Cl ovulation.

     

Sex differences in blood amino acid concentration and cell/plasma distribution in the domestic fowl

The amino acid concentration of and distribution between the cell and plasma of the blood of male and non-laying female domestic fowl have been determined. No significant differences in plasma amino acid content were observed between the sexes, except for higher serine and lower asparagine concentrations in the female. Hens had higher intracellular concentrations of aspartate, hydroxyproline, arginine, lysine and cystine and lower concentrations of cysteic acid and taurine. The proportion of amino acids carried in the blood cells of fowls was about 80%, a value that is much higher than that found in mammals. The mean ratio of combined total amino acid concentrations between plasma and cells was about 8-fold, again much higher than the corresponding figures in mammals.     

Autoproteolytic activity in the seminal plasma of the domestic fowl

Acid and neutral proteolytic activity was found in chicken seminal plasma. This proteolytic activity can markedly change the plasma polypeptide pattern due to partial protein degradation.     

The relationship between yolk cholesterol and total lipid concentration throughout the first year of egg production in the domestic fowl

1. Variation of egg yolk cholesterol and total lipid concentration (mg/g wet yolk) throughout the first year of egg production for the domestic fowl is described.

2. Yolk cholesterol concentration decreases between 20 and 30 weeks of age, and then remains constant until 70 weeks of age. Yolk total lipid concentration increases to a maximum at 40 weeks of age before decreasing to its original value at 60 and 70 weeks of age.

3. Bird means for yolk cholesterol and total lipid concentration are negatively related at 20 weeks of age, and essentially independent for the remainder of the first year of egg production.

4. Variation for yolk cholesterol concentration between 30 and 70 weeks of age appears to be a consequence of differences in the proportion of cholesterol to other lipid components.

5. Uptake of plasma lipoproteins characteristic of the immature bird is likely to be responsible for the high yolk cholesterol concentration at 20 weeks of age.     

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.     

Changes in the concentration and composition of biliary and serum bile acids in the young domestic fowl

1. Concentrations of biliary and serum bile acids, their molecular compositions and serum cholesterol concentrations were determined in chicks at 2, 3, 4 and 6 weeks of age. 2. The concentration of biliary bile acid was maximal at 3 to 4 weeks, decreasing by 6 weeks of age. 3. The serum concentration of bile acid was maximal at three weeks of age. 4. Serum total cholesterol increased from two weeks and was maximal at 6 weeks of age. 5. Chenodeoxycholic acid was the predominant biliary unconjugated bile acid. 6. Tauro-chenodeoxycholic acid and tauro-cholic acid were the dominant molecular species of biliary and serum conjugated bile acid.     

Fluctuations in total calcium and magnesium in the plasma and uterine fluid of the domestic fowl

Fluctuations in calcium and magnesium were measured in the shell gland fluid and blood from the inferior oviducal vein of the domestic fowl throughout the laying cycle.

It was concluded that:

1. The variations in calcium concentration reflected both the known uptake of this ion by the albumen and medullary bone formation and destruction.

2. The variations in magnesium concentration did not parallel the changes in calcium concentration.

3. Magnesium was released into the blood during medullary bone formation.

     

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.     

Capillariasis in the domestic fowl in New Zealand

Abstract

Extract

With the increase in more intensive methods of poultry production in recent years, worms of the genus Capillaria Zeder 1800 (hairworms) have become an important factor contributing to disease in chickens and turkeys. Apart from causing death, they are also responsible for lower growth rates, decreased egg production, and decreased fertility of the flock (Platt and Schwabe, 1958 Platt, C. S. and Schwabe, O. 1958. A notation on the egg production and mortality of pullets free of capillary worms. Poultry Sci., 37: 727–727.  [Google Scholar]; Geevaerts, 1962 Geevaerts, J. 1962. Bestrying van capillariose bij driven en kippern door methyridine. Vlaam. Diergeneesk. Tijschr., 31: 105–113.  [Google Scholar]; Norton and Joyner, 1965 Norton, C. C. and Joyner, L. P. 1965. Experimental chemotherapy of infection with Capillaria obsignata. J. comp. Path., 75: 137–145. [Crossref] , [Google Scholar]; Wakelin, 1965 Wakelin, D. 1965. A survey of the intestinal helminthes parasitic in the British domestic fowl. J. Helminth., 112: 191–200.  [Google Scholar]), Unfortunately, these parasites have been relatively neglected in research and survey work. Far more interest has been devoted to the more obvious nematode parasites of poultry, such as Ascaridia galli and Heterakis gallinarum. This can, in part, be explained by the facts that Capillaria spp. are difficult to work with, they are not easily detectable and infections are difficult to establish under experimental conditions.     

Dynamics of urea concentration in blood cells of the domestic fowl during early post-incubation ontogenesis]

Urea was determined by means of diacetyl monoxim in the blood cells of 80 cockerels of the initial breed White Leghorn, commercial hybrid Primant. The highest urea concentration was ascertained on the 15th day of life: 392.33 +/- 85 mg per 10(12) blood cells. The content of urea in the blood cells irregularly deceased with the age of the cockerels. The minimum urea concentration was obtained on the 40th day of post-incubation life: 63.40 +/- 56.5 mg per 10(12) blood cells.