The effects of restricted feeding on adrenal cortical activity in the immature domestic fowl

1. The effect of reducing food intake to 75% of the ad libitum intake was determined from hatching to 8 weeks in young Light Sussex chickens.

2. Restricted birds were lighter throughout the experiment.

3. Relative adrenal weight tended to be greater in restricted birds but the difference decreased with time.

4. There was no depletion of adrenal cholesterol: from week 5 there was a significantly greater amount in the adrenals of restricted birds.

5. After 1 week of restriction plasma corticosterone concentration was 73% greater than in controls. It decreased progressively, falling within the normal range at 5 weeks.

6. Restricted birds were hypoglycaemic from weeks 2 to 7 and hyper‐lipacidaemic throughout. A negative correlation between plasma glucose and free fatty acids was found.     

Plumage loss in medium‐bodied hybrid hens: The effect of beak trimming and cage design

1. Plumage loss was assessed by visual scoring in 288, 78‐week‐old hens, housed as groups of four in battery cages, which differed in the design of the cage front and the position of the nipple drinkers.

2. Half the hens had undergone beak trimming at 18 weeks, but in many cases regrowth had occurred.

3. Plumage damage and loss was significantly reduced in beak‐trimmed birds compared with birds with normal beaks. Tier and cage design had no effect.

4. This finding supports the idea that feather pecking is the important factor in causing plumage damage, rather than abrasion.

5. A comparison between 64 birds in which beak regrowth had occurred, and 64 in which it remained truncated, showed that both groups had similar plumage scores.

6. It appears to be the beak‐trimming procedure which is important; subsequent regrowth being irrelevant.     

Protein and energy metabolism in two lines of chickens selected for growth on high or low protein diets

1. Genetic adaptation was investigated in broilers selected for seven generations on a normal (A) or a low (B) protein diet.

2. Protein and energy metabolism were studied in males from these selected lines fed on a diet of intermediate protein content.

3. All selected birds retained more nitrogen than those studied 10 years previously.

4. There was no difference in nitrogen retention between groups, although relative growth rate of group B birds was higher.

5. Heat productions relative to gross energy intake were 0.38 (group B) and 045 (group A). Energy retentions relative to gross energy intake were 0.39 (group B) and 0.35 (group A); the difference being primarily due to higher fat retention in group B.

6. Using a common maintenance requirement for metabolisable energy, group B utilised metabolisable energy for growth (0.78) better than did group A (0.71).

7. At 53 d of age plasma glucose (10%) and insulin (50%) were higher in group B than in group A.     

Effects of evisceration and storage temperature on changes in meat quality of traditional farm‐fresh Turkeys

1. Conditions affecting the keeping quality of traditional farm‐fresh turkeys were investigated.

2. Storage of uneviscerated Wrolstad turkeys at 4 °C for 10 days caused no statistically significant changes in meat flavour or texture.

3. During further storage at —2 °C, however, there was a slight but significant change in flavour, which became more marked with time in birds which had been eviscerated after the initial period at 4 °C.

4. Both eviscerated and uneviscerated birds became slightly tougher during storage.

5. Initial holding at 4 °C increased the numbers of psychrotrophic bacteria on the skin by about 10³ but subsequent changes at — 2 °C were slight for uneviscerated birds.

6. Eviscerated carcases had higher counts than uneviscerated birds after storage at — 2 °C and, although ‘off’ odours were not detected, spoilage appeared to be imminent at the end of the 20‐d period.     

Caegal growth in the domestic fowl following surgical manipulation

1. Some effects of removing increasing proportions of the left caecum on the remaining caecal tissue and on the right caecum were studied in young chicks during a period of 35 d. The chicks were 22 d old when the operations were carried out.

2. No differences were detected between the gains in weight of the control and experimental groups of birds.

3. A marked negative linear relationship was observed between the dry weight of the amount of caecal tissue removed when the birds were 22 d old and the weight of the left caecum at the end of the experiment.

4. The average growth rate of the left caecum (g dry tissue/week) was found to be dependent on the estimated weight of caecal tissue remaining after surgery.

5. No evidence was obtained to indicate that the growth of the right caecum responded to the removal of the left caecal tissue.

6. The morphology and histology of the operated caeca were found to be similar to the equivalent regions of the unoperated caeca. Surgical interference was not followed by any major changes in mucosal architecture.

7. In birds which had experienced unilateral caecectomy, the discharge of caecal faeces usually stopped for about 2 d. When caecal defaecation was resumed, the pattern of defaecation appeared to be the same as that observed in sham‐operated birds with both caeca intact.     

The occurrence of salmonellae during the rearing of broiler birds

1. The incidence of salmonellae was studied in two broiler houses at each of two commercial sites in an integrated commercial enterprise.

2. Salmonellae were not isolated from the empty, cleaned and fumigated houses and only on one occasion from the foodstuffs.

3. Salmonellae were isolated from the environment of the chicks and spasmodically from the litter, water troughs and dust.

4. The incidence of infection of the chicks did not influence the number of isolations of salmonellae from the environment of the birds during rearing.

5. Water in the water troughs rather than foodstuffs appeared to be the major oral route of infection or re‐infection of birds during rearing.     

Furazolidone in chicken: case study of an incident of widespread contamination

1. Furazolidone, a nitrofuran antibiotic, was prohibited from the use in food-producing animals in the European Union (EU) in 1997. In 2002, the EU restricted the import of poultry meat and aquaculture species from countries where furazolidone residues had been detected.

2. By 2004, however, residues of the side-chain metabolite, 3-amino-2-oxazolidinone (AOZ) of furazolidone, were detected in chicken meat produced in Northern Ireland.

3. With the random spread of positive results across farms of a single integrated organisation, including organically reared flocks, it seemed unlikely that the source of residues was due to illegal use of the drug, but more likely caused by a source of contamination.

4. Potential sources investigated were as follows: furazolidone contamination of feedstuffs, a “hot spot” of furazolidone in poultry houses, contamination occurring within breeding stocks and transferred with the birds to broiler growing houses, and furazolidone contamination of the water supply.

5. Furazolidone contamination was associated with birds reared in houses more than 10 years old.

6. Contamination was traced to the water supply of poultry houses, where un-dissolved furazolidone, legally administered prior to 1997, had settled to the bottom of water storage tanks. It remained un-disturbed until 2004 when the integrator changed the procedure for cleaning water tanks between crops of birds.

7. The use of Proxitane, a hydrogen peroxide disinfectant, caused effervescence within the tank such that small quantities of furazolidone were dissolved, delivered to birds via drinkers and subsequently caused residues in the broiler meat.

8. The environmental impact of the contamination was investigated by testing soil and grass from land adjacent to an organic poultry house to which birds had access.

9. Mechanisms of contamination and how residues may be spread throughout a large integrated poultry system are not restricted to furazolidone. Incidents of contamination are even more likely when using licensed drugs where the drugs may be present on-farm in large quantities.     

The choline and sulphur amino acid requirements of broiler chickens fed on semi‐purified diets

1. Growth and food conversion efficiency of broilers were reduced at low dietary choline concentrations. These effects were accentuated by low dietary total sulphur amino acids (TSAA).

2. Increased mortality, perosis and other pathological changes involving a number of tissues were observed in birds fed on a low‐choline diet.

3. Methionine replaced part of the dietary requirement for choline at low dietary choline concentrations.

4. High dietary concentrations of choline (> 1 750 mg/kg) increased the requirement for dietary TSAA.

5. Increasing the dietary choline while maintaining the TSAA at an inadequate level may decrease performance.     

Asociation of plasma 5'‐nucleotidase and alkaline phosphatase with production traits in chickens: Effects of age and housing systems

1. The housing system, age of pullets and their interaction had a significant effect on plasma 5'‐nucleotidase and alkaline phosphatase activities.

2. Activities were higher in birds in cages than in those on the floor, reflecting perhaps the stress of caging. Activities increased with age.

3. Activities were higher in pullets selected for higher production.

4. The type of housing had no effect on egg production, but age at first egg, egg weight and 40‐week body weight were found to be affected significantly.     

Corticosterone and fat deposition in broiler chicks: Effect of injection time,breed, sex and age

1. Corticosterone (680 μg/kg body weight per day) given as six daily injections to 3‐ or 7‐week‐old chicks decreased weight gain, but increased food consumption, abdominal fat pad weight, skin dry matter, relative liver size and liver fat concentration.

2. Time of day of injection did not modify the response to corticosterone of 3‐week‐old chicks kept under natural daylight nor of 7‐week‐old broilers receiving additional illumination.

3. Pure White Rock chicks and Cornish x White Rock crossbred chicks responded similarly to corticosterone injections at 3 weeks of age.

4. Seven‐week‐old female birds treated with corticosterone had significantly larger abdominal fat pads than similarly treated males.

5. Corticosterone injection was more effective in increasing the proportion of liver fat in 7‐week‐old birds than in 3‐week‐old ?hicks.

6. The increased amount of abdominal and liver fat due to corticosterone injections administered at 3 weeks of age disappeared after 3 weeks, but growth depression was still evident.     

Intermittent lighting and feeding schedules for broilers incorporating long periods of darkness

1. Intermittent lighting and feeding schedules incorporating long periods of darkness and periods without access to food were applied to growing broilers.

2. Birds exposed to a 2 h light(L): 10 h dark(D) lighting schedule with feeding restricted to the light periods ate significantly less food and grew more slowly than conventionally‐reared birds. Satisfactory growth and efficiency of food utilisation were obtained by allowing these birds access to food during the dark periods.

3. Altering the lighting schedule to 2L:6D resulted in birds with food intakes and growth rates similar to those reared conventionally, even when feeding was restricted to the light periods.

4. Releasing birds from the light and food restriction for the 2 weeks preceding slaughter resulted in greater food consumption which was not characterised by significantly better growth or food utilisation.

5. Feeding a diet of high energy or pelleting a diet of low energy during the period of restriction increased food intake and improved growth rate.

6. The response of broilers to intermittent lighting and feeding was not significantly influenced by ambient temperature within the range 16 to 35 °C or by the energy concentration of the diet fed before the introduction of the intermittent schedule.     

Efect of intermittent feeding on blood plasma growth hormone and prolactin in chickens of a heavy breed

1. Variations in plasma growth hormone (GH) and prolactin concentrations were determined during growth (at 20, 33, 56 and 83 d of age) in ad libitum (control) and intermittently (alternate days) fed chicks.

2. In each group of birds the concentration of plasma GH was inversely related to age. The mean prolactin concentration was highest in the youngest (20‐d‐old) birds.

3. The concentration of plasma GH in the intermittently‐fed birds deprived of food for 24 h (depleted birds) was significantly higher than that in the controls at 33, 56 and 83 d of age. The mean GH concentration in the intermittently‐fed birds 24 h after refeeding (repleted birds) was less than that in the depleted ones.

4. The overall mean concentration of plasma prolactin in the depleted birds was significantly less than that in the control and repleted birds.

5. These results are consistent with the effects of fasting on GH and prolactin secretion and demonstrate that growth retardation in the intermittently‐fed birds was not due to impaired GH secretion.     

Effects of ageing and gonadal steroid hormones on prolagtin concentration in the anterior pituitary of the chicken

1. Effects of ageing and gonadal steroid hormones on pituitary prolactin (PRL) concentration in the chicken were investigated.

2. No difference was found in the qualitative electrophoretic patterns of the anterior pituitary homogenates at different ages and between the sexes.

3. Pituitary PRL concentrations in males were generally higher than in females.

4. Pituitary PRL concentrations in castrated immature cockerels were higher than in intact birds, while PRL concentration was depressed by the injection of testosterone propionate or oestradiol benzoate.

5. Prolactin concentration in intact immature cockerels was decreased by daily injection of testosterone or oestradiol for 3 weeks but not by injection of the hormones for 1 week.     

Lipopolysaccharide reduces food passage rate from the crop by a prostaglandin-independent mechanism in chickens

1. We examined the effect of lipopolysaccharide (LPS), a component of Gram-negative bacteria, on food passage in the digestive tract of chickens (Gallus gallus) in order to clarify whether bacterial infection affects food passage in birds.

2. Food passage in the crop was significantly reduced by intraperitoneal (IP) injection of LPS while it did not affect the number of defecations, suggesting that LPS may affect food passage only in the upper digestive tract.

3. Similar to LPS, prostaglandin E2 (PGE2), one of the mediators of LPS, also reduced crop-emptying rate in chickens while it had no effect on the number of defecations.

4. Pretreatment with indomethacin, which is an inhibitor of cyclooxygenase (COX), a prostaglandin synthase, had no effect on LPS-induced inhibition of crop emptying.

5. IP injection of LPS did not affect the mRNA expression of COX2 in the upper digestive tract of chickens.

6. It is therefore likely that LPS and PGE2 reduced food passage rate in the crop by a prostaglandin-independent pathway in chickens.     

Effects of dietary dilution with sand on broiler performance to 8 weeks of age

1. Nine hundred and sixty 1‐d‐old unsexed broiler chicks were used in a 4×4 eight weeks trial. Proprietary starter and finisher diets were given diluted with sand in the proportions of 0, 50, 75 and 100 g sand/kg diet.

2. At 8 weeks of age, birds receiving 50 and 75 g sand/kg diet were significantly heavier than those receiving the basal diet and 100 g sand/kg diet.

3. Birds receiving 0 and 100 g sand/kg diet consumed similar quantities of basal diet and yielded similar corrected food:gain ratios.

4. Dietary dilution with sand had no significant effect on mortality, apparent carcase yield, preventriculus weight, gizzard weight and intestinal length. Crop weights were significantly greater in birds given 100 g sand/kg diet to the age of 4 weeks.

5. The litter moisture content was significantly less in pens containing birds receiving 75 or 100 g sand/kg diet after 5 weeks of age.     

Identification of antibodies against hydropericardium syndrome in wild birds

1. Domestic fowl and free-living birds were examined for the presence or absence of antibodies against hydropericardium syndrome (HPS) using an indirect haemagglutination assay.

2. Two-hundred and eighty serum samples of commercial (45 broilers, 20 adult layers and 15 Fayoumi fowl) and wild birds, including 65 peafowl, 45 pigeons, 10 crows, 30 house sparrows, 10 doves, 15 ducks, 10 parrots and 15 guinea fowl, were collected and examined.

3. The percentage of HPS-positive serum samples was 80% in house crows, 78% in pigeons, 7% in house sparrows and 6% in peafowl.

4. The sera obtained from parrots, doves, ducks and guinea fowl were all negative.

5. This study suggests that crows and pigeons could be carriers of the HPS agent.     

Effects of regular handling on growth in male and female chicks of broiler and layer strains

1. The effects of regular handling on growth and gain: food ratios in male and female chicks of layer (two strains) and broiler strains were examined from hatching to 3 weeks of age.

2. Growth was significantly enhanced by regular handling in broilers and the females of the layer strains and gain : food ratios were generally greater in the handled birds.

3. There were no significant treatment effects on growth or gain : food ratios in males of the layer strains.

4. Males had higher relative weight gains and gain : food ratios than females.     

The response of egg weight to the inclusion of different amounts of vegetable oil and linoleic acid in the diet of laying hens

1. Four diets containing different amounts of vegetable oil and linoleic acid were fed to White Leghorn hens throughout a full laying year.

2. Egg weight was poor with the low fat basal diet but increased in relation to the amounts of maize oil (4 and 30 g/kg) included in the diet.

3. With a diet containing 30 g olive oil/kg, egg weight was similar to that obtained with the diet containing the same amount of maize oil.

4. Rearing the birds on diets containing low or moderate amounts of linoleic acid did not affect the response to fatty acid content of the layer's diet.

5. It is concluded that the requirement of the laying hen for linoleic add is not higher than 9 g/kg but that egg weight does respond to higher dietary amounts of readily absorbable fatty acids.     

Effect of age and sex on the chemical composition of edible offal and blood from broilers

1. The effects of age and sex on the proximate composition and inorganic constituents in edible offal and whole blood from a commercial British broiler chicken strain were studied.

2. Although the protein content of all tissues varied with age, the only statistically significant effect was on the level of protein in the gizzard.

3. The moisture content of the gizzard was significantly affected by age and blood by age and sex.

4. The fat content of the gizzard was significantly affected by age, as was the effect of sex on the fat content of blood.

5. The ash contents of heart and gizzard were significantly affected by age.

6. The phosphorus contents of the gizzard, heart and liver were significantly affected by age, as were the chloride content of heart and the calcium content of the liver. Blood potassium was significantly affected by sex. Fluctuations in the contents of other elements are discussed.

7. The variability in organ composition is discussed with respect to the degree of trimming and preparation of the samples.     

Effects of method of processing and chilling of Turkey carcasses on processing losses,water absorption and yields

1. The effects of wet or dry plucking, wet or dry evisceration procedures and method of chilling on processing losses and water uptake during chilling were studied using 19‐week‐old female large white turkeys.

2. Dry plucking increased weight loss due to plucking and eviscerating, and reduced chilled carcass yield.

3. Dry eviscerating increased carcass water uptake during chilling.

4. Pre‐chilling with running water increased carcass water uptake compared with chilling in ice and water alone.

5. Water uptake during chilling appeared to be increased by longer eviscerating time.