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.     

A mathematical representation of the Ovulatory cycle of the domestic hen

1. The ovulatory cycle of the domestic hen (Gallus domesticus) was postulated to be the result of the interaction of two independent systems.

2. A circadian system was postulated to control the restriction of ovulation to an 8‐h period of the day under conventional 14 h light: 10 h dark regimes.

3. The final phase of follicular maturation was postulated to commence after ovulation of the preceding ovum in the hierarchy.

4. Ovulation was postulated to occur when a mature follicle was present in the ovary during the appropriate phase of the circadian‐linked system.

5. The predicted times of oviposition were within the standard error of the observed times of oviposition under 21‐, 24‐ and 28‐h photoschedules.

6. It was concluded that this hypothesis for the control of the ovulatory cycle of the hen is consistent with current knowledge.     

Comparison of the productive perform. Ances of the Sinai Bedouin fowl,the white leghorn and their crossbreds: Study under laboratory conditions

1. A comparison of the productive performances of the Sinai Bedouin fowl (from the Sinai desert), the commercial White Leghorn and their reciprocal crossbreds was made under uniform normal conditions.

2. The Sinai produced significantly fewer, smaller eggs, resulting in lower egg mass output (g/bird d), than the Leghorn and the crossbreds.

3. Egg weight of both crossbreds was intermediate between Sinai and Leghorn but laying rate was closer to that of the Leghorn.

4. Differences in egg mass output apparent at 8 to 10 months of age decreased considerably with age.

5. These findings suggest that selection or crossbreeding of the Sinai might improve productive performance while maintaining improved eggshell quality.     

Isolation,identification and antibiotic resistance of Campylobacter strains isolated from domestic and free-living pigeons

1. The aim of this study was to evaluate the occurrence of Campylobacter spp. in domestic and free-living pigeons and to evaluate the antibiotic resistance profiles.

2. The material consisted of cloacal swabs obtained from 108 homing pigeons and fresh faeces from 72 wild birds from Lublin and its vicinity. The identification of strains isolated on differential/selective media for Campylobacter spp. was carried out by MALDI-TOF and PCR. The susceptibility to antibiotics was evaluated by minimum inhibitory concentration (MIC) in Mueller-Hinton broth.

3. A total of 35 strains of Campylobacter spp. were isolated; 27 were identified as Campylobacter jejuni and 8 as Campylobacter coli. Over half of the isolates were resistant to erythromycin and streptomycin, 40% of strains were resistant to tetracycline and ampicillin and 37% isolates were resistant to amoxicillin. Resistance to two or more antibiotics was observed in all strains tested.

4. The results indicate that both domestic and free-living pigeons are reservoirs for bacteria of the genus Campylobacter, which are characterised by varied and growing resistance to commonly used antibiotics.     

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.     

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.     

Encapsulated benzoic acid supplementation in broiler diets influences gut bacterial composition and activity

1. The present study investigated the effects of encapsulated benzoic acid (BA) supplementation in broiler feed on performance and gastrointestinal microbiota.

2. Eighty broilers were randomly divided into two groups. Birds in the control group were fed on maize–soybean-based diets. Birds in the treatment group were provided the same diet supplemented with 2 g/kg BA encapsulated in a vegetable oil matrix.

3. At the end of the trial (d 35), pH, bacterial composition and metabolites were determined in the crop, jejunum, ileum and caecum.

4. Growth performance variables and pH were not significantly different.

5. BA concentration decreased rapidly in the proximal gut. However, the treatment diet showed higher BA in the crop, jejunum, ileum and caecum.

6. Total lactate in the crop and D-lactate in the jejunum was higher in the BA treated group. Caecal total and branched chain fatty acids were decreased due to the treatment.

7. Lactobacilli populations were significantly altered by BA supplementation. A trend for increased lactobacilli was observed in the crop, while it became significant in the jejunum and ileum. Lactobacillus species responded differently to the treatment. Four of 5 measured Lactobacillus species, particularly in the ileum, followed the course observed for total lactobacilli; only Lactobacillus salivarius was not modified.

8. Correlation analysis showed that BA modified the intestinal microbiota. Lactobacilli correlated negatively to all studied clostridial clusters and enterobacteria. Clostridial clusters IV and XIVa were significantly increased in the jejunum, whereas only clostridial cluster XIVa was increased in the caecum.

9. Encapsulated BA modified the intestinal microbiota which can lead to the conclusion, that the main beneficial mode of action of BA in the gut appears to be the enhancement of lactic acid bacteria, which in turn may act as a vanguard against pathogens.     

A 31P topical magnetic resonance study of embryonic development in hens' eggs

1. A ³¹P topical magnetic resonance study of whole chicken's eggs in vivo is described.

2. Resonances from adenosine triphosphate, phosphocreatine, inorganic phosphate and phosphorous storage protein were observed. These changed in relative intensity as the embryo developed.

3. No ill effects due to exposure to radiofrequency radiation or magnetic fields were observed.

4. It is concluded that topical magnetic resonance can make a useful contribution to the study of embryonic development in avian eggs.     

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.     

The occurrence of giant fibres in different muscles of two chicken genotypes

1. The occurrence of Giant Fibres (GF) in three muscles (Pectoralis major (PM), Iliotibialis lateralis and Semimembranosus) with different types of energy metabolism was studied in slow- and fast-growing chicken strains.

2. A total of 20 one-day-old Leghorn chicks (slow-growing) and 20 broiler (Ross 508) chicks (fast-growing) were reared to 100 and 45 d, respectively.

3. A small percentage of GF was seen in pre rigor muscle samples even at 3 min post mortem in both genotypes and in all muscle types studied.

4. From 3 min to 24 h post mortem GF increased both in Leghorn and broiler chickens but to a different extent according to muscle type and genotype.

5. The highest GF 24 h post mortem value was found in the PM muscles belonging to the fast-growing broiler line.

6. It was concluded that every type of muscle can develop GF, but this phenomenon is more evident in the PM especially in animals selected for increased growth rate.     

The importance of convection in the determination of the water vapour conductance of avian egg shells

1. It was confirmed that convection across the avian egg shell surface does not affect diffusive transport of water vapour through the shell.

2. Relative water vapour conductance, i.e. the ratio between the water vapour conductance as determined in a desiccator and the actual water vapour conductance, as well as relative humidity in the desiccator are influenced by the total rate of water loss of the eggs in the desiccator.

3. The total rate of water loss is influenced by the number of eggs in the batch, their average actual water vapour conductance, desiccator temperature and barometric pressure.

4. Therefore water vapour conductance is easily underestimated, in particular when determined in still air at a small surface area of desiccant.

5. All the above effects are considerably reduced by convection.

6. Further improvements in technique are suggested, particularly for practice where determinations have to be made for a relatively large batch of eggs.     

Gene expression profile of IGF1 and MSTN mRNA and their correlation with carcass traits in different breeds of geese at 70 d of age

1. The expression of insulin-like growth factor-1 (IGF1) and myostatin (MSTN) mRNA in breast and leg muscle was quantified in 70-d-old Taihu and Wanxi geese by using a Multiplex Competitive Fluorescent–PCR method and the correlations between mRNA levels and carcass traits were analysed.

2. IGF1 mRNA expression in breast muscle in Taihu geese was significantly higher than that in Wanxi geese and the MSTN mRNA level in leg muscle in Taihu geese was significantly higher than that in Wanxi geese.

3. There was no significant difference in breast muscle MSTN or leg muscle IGF1 mRNA expression between the two breeds.

4. Within the same breed, the IGF1 mRNA expression in leg muscle of male geese was significantly higher than that in female geese, and MSTN mRNA expression in leg muscle was significantly higher than that in breast muscle.

5. There was no difference in the IGF1 mRNA expression between tissues.

6. There was a positive correlation between IGF1 mRNA and MSTN mRNA and a negative correlation between IGF1 mRNA expression of breast muscle and leg muscle ratio.

7. In Wanxi geese, MSTN mRNA expression in leg muscle was negatively associated with body weight and leg muscle weight.     

Influence of ascorbic acid on the adverse effect of feeding a diet containing excess tyrosine to chicks

1. The effects of dietary or parenteral administration of ascorbic acid on the adverse effects of excess dietary tyrosine were investigated with young male White Leghorn chicks in a 2‐week experiment.

2. Addition of 10 g ascorbic acid/kg to the control diet (without excess tyrosine) produced no beneficial effects on performance. Excess dietary tyrosine caused depressions in all measures of performance.

3. Adding 0.1, 1, 10 or 20 g ascorbic acid/kg to the diet containing excess tyrosine tended to improve performance.

4. Subcutaneous injection of 50 mg ascorbic acid/bird d to chicks receiving excess tyrosine brought about a significant improvement in body‐weight gain.

5. The elevation of plasma free tyrosine caused by excess dietary tyrosine decreased as dietary ascorbic acid increased.

6. Ascorbic acid can alleviate, though not completely counteract, the adverse effect of excess dietary tyrosine.     

Effects of high inclusion rates of salseed meal in the diet of chicks

1. Starter diets containing either maize or salseed meal to replace the maize were fed to chicks over a period of 2 weeks.

2. Growth rate, food intake, food utilisation and proportion of dietary nitrogen retained were much poorer in chicks receiving salseed meal.

3. The chicks receiving salseed meal developed pathological lesions in liver and kidney.

4. The red blood cell count, white blood cell count, haemoglobin concentration and packed cell volume of the chicks receiving salseed meal were lower than those of chicks receiving maize.

5. The apparent metabolisable energy value of salseed meal was determined as 6.83 MJ/kg.     

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.     

Evaluation of bone strength,keel bone status,plumage condition and egg quality of two layer lines kept in small group housing systems

1. The aim of the present study was to determine the influence of large (54 or 60) and small (36 or 40) group sizes and tiers of the small group housing system “Eurovent German” on tibia and humerus bone breaking strength, keel bone status, plumage condition and egg quality for two commercial layer lines, Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), at the same stocking density (890 or 830 cm²/bird).

2. In 4 consecutive trials, 4752 hens were recorded for keel bone status. Evaluation of plumage condition was made for 1440 hens and bone breaking strength was recorded for 1200 hens. A total of 4962 eggs were analysed for internal and external egg quality traits. Analyses involved 30 small group compartments per trial.

3. The layer line had a much more pronounced influence on humerus breaking strength than on tibia breaking strength.

4. Plumage condition, particularly on the neck, was positively correlated with humerus breaking strength in both layer lines.

5. An average of 34% of LB and 23% of LSL hens showed keel bone deformities, with higher proportions of slight deformities.

6. Slight keel bone deformities, rather than moderate to severe, increased significantly during the laying period.

7. Stocking density had no influence on bone breaking strength, keel bone status and egg quality traits.

8. LB layers had a 1.4-fold higher humerus, but only a 1.06-fold higher tibia breaking strength compared to LSL layers.

9. Tibia breaking strength was significantly affected by the interaction of group size and layer line. LSL layers in small groups had lower tibia breaking strengths than those of the large groups.     

Cellular changes in the granulosa layer of the maturing ovarian follicle of the domestic fowl

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.     

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.     

Effects of a dry-ice process on surface and carcase decontamination in the poultry industry

1. The objective of this study was to evaluate the effects of dry-ice decontamination on equipment and carcase surfaces in a poultry slaughterhouse and to present an effective alternative method to the conventional decontamination processes.

2. Appreciable reductions occurred in total aerobic mesophilic bacterial counts of surface swab samples treated with dry ice (maximum difference 3.92 log cfu/100 cm²).

3. After dry-ice treatment, Listeria spp. were detected on surfaces of pluckers and chiller cylinders, whereas Salmonella spp. were totally inhibited.

4. A dry-ice spraying application was more effective than a dry-ice immersing application on total aerobic mesophilic bacteria and yeast and mould counts on poultry carcases.

5. Dry-ice treatment has advantages over conventional processes. Unlike other decontamination techniques, there are no residues, so no need to wash off chemical residues from surfaces as it removes contaminants effortlessly and is environmentally friendly.

6. Dry-ice blasting of production equipment can reduce the microbial load and has potential for use in the poultry industry.