The effect of heat treatment and enzyme supplementation on the nutritive value of barley for broiler chicks

1. The effect of heat treatment and enzyme supplementation on the nutritive value of barley was studied.

2. In only one experiment was weight gain significantly improved when the barley was heated.

3. Autoclaving barley at 120 °C for 30 min reduced dietary dry matter digestibility and treating the barley with dilute acid before heating had no effect on its nutritive value.

4. Supplementing diets containing commercial barley with a‐amylase produced slightly conflicting results in that there was an improved weight gain, food conversion efficiency and digestibility value in two of three experiments.

5. The digestibility and metabolisable energy values of a North American six‐row spring barley (Glacier) were significantly improved by enzyme supplementation.

6. The effect of the enzyme on diets containing a high amylose barley (Glacier Pentlandfield) was positive but not significant.     

Diets containing conventional,naked and high‐amylose barleys for broilers

1. Samples of Glacier (Pentlandfield), North American Glacier and Nackta (naked) barleys contained 112, 123 and 118 g of protein per kg dry matter, respectively.

2. Substitution of Nackta for conventional feed‐grade barley allowed a decrease of 10 kg per Mg in the fish meal content of a broiler diet, without impairing bird performance.

3. Replacement of conventional barley by Glacier (Pentlandfield) high‐amylose barley significantly increased food intake and body weight of broiler chickens at 56 d of age.     

Effect of soaking,germination, and enzyme treatment of whole barley on nutritional value and digestive tract parameters of broiler chickens

1. An experiment was carried out to determine the effect of soaking at 0°C, soaking at room temperature, germination, or enzyme treatment of whole barley on feeding value and digestive tract parameters of 2‐ to 4‐week old broiler chickens given diets with 700g/kg whole barley.

2. Soaking or germination decreased the soluble and total β‐glucan content (P<0.05) and, except for soaking at 0°C, the acid extract viscosity of the grain also decreased (P< 0.05). Germination and soaking in the presence of enzymes produced the lowest β‐glucan content and viscosity.

3. Except for soaking in cold water, the soaking, germination and enzyme treatments increased weight gain and decreased food: gain ratio (P< 0.05). Correspondingly, the digestibility of protein, fat, and ash, and the digestible energy content, increased (P< 0.05) after enzyme treatment or germination.

4. Chickens fed on enzyme‐treated or germinated barley diets had intestinal contents with a greater proportion of dry matter and lower viscosity than chickens fed on untreated barley (P< 0.05). Consequently, the cages and chickens were cleaner (P< 0.05) and the weight of digestive organs as proportion of live weight was lower.

5. Particle size analysis of excreta revealed that whole barley was efficiently ground by the gizzards of 16‐d‐old chickens, and very few whole kernels were found.     

Influence of β ‐glucanase on feeding value of barley for poultry and moisture content of excreta

1. The cause of the sticky droppings and poor performance that can occur when barley is fed to poultry was investigated.

2. The problems could be overcome by water‐treatment of the barley or by addition of β‐glucanase.

3. The problems appear to be caused by a viscous factor, which is hydrolysed by β‐glucanase. Water‐treatment allows hydrolysis by enzymes in the barley.

4. Heat‐treatment of barley denatures hydrolytic enzymes and prevents reduction in viscosity.     

Traits influencing the hatching performance of Japanese quail eggs

1. Japanese quail eggs from moderately heavier sires showed superior fertility; while fertile eggs from moderately heavier dams hatched slightly better than the eggs from lighter dams.

2. Higher rates of fertility and hatchability of Japanese quail eggs were observed from parents of 10 to 19 weeks of age, with peak fertility and hatchability at 14 and 12 weeks of age, respectively.

3. Sex ratios of 1:2 to 1:5 gave comparable fertility and hatchability results.

4. The hatching performance of quail eggs from cage and deep litter reared breeders was comparable.

5. Fertility and hatchability were directly proportional to the egg weight.

6. Quail egg shell colour, tints and blotches were found to influence hatching performance.

7. Storing quail eggs at 16 ± 2°C and 75 ± 5% relative humidity for more than 4 d reduced hatchability.

8. Hatchability of eggs stored at room temperature was improved if they were sealed in polyethylene bags.

9. Provision of light during the first 14 d of incubation resulted in a photo‐acceleration of about 3.2 h.     

Effects of cultivar,pelleting and enzyme addition on nutritive value of barley in poultry diets

1. The effect of pelleting process and Trichoderma viride enzymes (TVE) addition on apparent metabolisable energy, corrected for nitrogen balance (AMEn) and on productive value of practical diets containing 40 and 45% of three different barley cultivars and one wheat were studied in poultry.

2. The effect of the pelleting process on AMEn was inconsistent and was dependent on the cereal included and the addition of enzyme.

3. The growth trial showed a significant effect of enzyme addition to pelleted diets over the whole growth period (0 to 42 d). Addition of TVE improved weight gain and food efficiency by 1.3% and 2.9%, respectively and decreased food intake by 1.6% between 0 and 22 d. In the finisher period (23 to 42 d) TVE improved efficiency by 2.8% and reduced food intake by 2.9%.

4. The incidence of sticky droppings was related to the viscosity of barley used, and enzyme supplementation reduced it. Both pelleting and enzyme addition increased dry matter content of excreta.

5. At the end of the experiment, 14 animals per treatment were slaughtered and carcass yield, viscera weight and abdominal fat were determined.     

Metabolic and anatomical adaptations of light‐bodied chicks to intermittent feeding

1. Chicks of a light‐bodied strain were deprived of food on alternate days from 15 to 46 d of age.

2. Hyperphagia, amounting to twice the intake of control birds early in the experiment, occurred on the repletion day.

3. Final body weight attained 80% of that of the controls.

4. Body fat concentration decreased at first but returned to that of controls after 3 weeks.

5. A consistent hyperlipaemia was observed after food deprivation or restoration.

6. There was a marked increase in the digestive enzymes found in the small intestine, but not in the pancreas during the repletion day.

7. These responses may be considered as mechanisms to reduce the physiological manifestations of starvation.     

Photoperiod and seasonal influences on the growth of turkey hens

1. The influence of photoperiod and time of year on the growth of hen turkeys was investigated.

2. Photoperiod treatments consisted of computer simulations of day lengths which occur naturally in the spring and autumn of the year. Both photoperiod treatments were given to hens in the autumn and spring.

3. Data were collected for growth evaluations at 2‐ to 4‐week intervals to 16 weeks of age. No significant season × photoperiod interactions occurred.

4. The spring trial resulted in greater body weights and better food conversions (food/gain) than the autumn trial.

5. Simulated autumn daylengths resulted in greater body weights and improved food efficiency at 16 weeks of age compared with simulated spring daylengths.

6. The pattern of growth (period changes) was influenced by season, but not photoperiod.

7. Season and photoperiod both have important and independent influences on the growth of the turkey hen.     

Effects of short intermittent lighting on food consumption and performance of dwarf broiler breeders and progeny

1. Two hundred and sixty four dwarf broiler breeder hens were subjected to ad libitum or restricted feeding and to four lighting patterns: 15L (bright light):9D (dark), 15L:9d (dim light), 2L:10d: 1L:11d, (0.5L:3.5d) × 6.

2. Breeder hens fed ad libitum and subjected to either conventional or intermittent lighting ingested respectively, 25 g and 14 to 17 g more than hens restricted to 115 g/d.

3. Body weight was greater in hens fed ad libitum irrespective of the lighting pattern and of the amount of food intake.

4. Persistency of egg production was impaired by intermittent lighting.

5. Ad libitum feeding reduced egg fertility. The decrease was larger in breeder hens on intermittent lighting.

6. Hatchability was increased in hens submitted to the symmetrical lighting pattern (0.5L:3.5d).

7. Egg and chick weights were higher in hens fed ad libitum.

8. Shell index and shell breaking strength increased in restricted hens on the intermittent lighting pattern (0.5L:3.5d) × 6.

9. The best performance was obtained in restricted hens on the conventional lighting pattern.     

Inheritance of body weight and rate of gain in Japanese quail

1. The effects of hatch date, location and sex on the body weight and rate of gain in Coturnix coturnix japonica were examined.

2. The data conformed to a mixed model and adjustments were made for the fixed effects sex, hatch date and location. Adjustment improved the precision of the estimates by reducing the error variances significantly.

3. Rearing equal numbers of birds from each family at different locations made the interactions negligible.

4. Weight gain was greater if illumination intensity up to 35 d was less.

5. Females were not heavier on the 1st day but were heavier on the 14th and 35th days than males.

6. Variance components and genetic parameters were estimated.     

Digestibility studies in broiler chickens: Influence of genotype,age, sex and method of determination

1. The influences of genotype, age and sex on droppings digestibility coefficients of a compound food were studied using male and female broiler chickens of three different genotypes at 2, 4 and 6 weeks of age.

2. Because the traditional method of determination of droppings digestibility coefficients of nitrogen may lead to systematic errors in estimating the feeding value of foodstuffs, a method is proposed to determine the ileal digestibility coefficients. The ileal method is compared with the droppings method for a mixed food and for two foodstuffs: wheat and solvent‐extracted soyabean meal.

3. Birds selected for efficient food conversion showed distinctly higher digestibility coefficients for all nutrients than birds selected for high growth potential or birds from a commercial strain.

4. The influence of age on digestibility coefficients was not consistent.

5. Female birds showed digestibility coefficients which were, in general, 3% higher than those of male chickens.

6. Interactions between genotype and sex and between genotype and age for energy metabolisability were the only interactions observed for digestibility measurements.

7. The method of determination influenced the amino acid digestibility coefficients of the mixed food and the relative feeding values of wheat and soyabean meal.

8. It is important to use well defined animals (genotype, sex, age) in evaluating foodstuffs.

9. The preferred method for determination of digestibility coefficients of nitrogen and amino acids is based on ileal sampling, although the differences in amino acid digestibility coefficients were small between methods.     

The influence of sample size on the choice of method and interpretation of incubation experiments

1. An equation relating batch size to between‐treatment differences has been adapted for hatchability studies and its implications for research considered.

2. Very large egg batches are required to detect small improvements in the hatchability of good hatching strains.

3. Small‐scale laboratory studies on hatchability are best confined to strains and species of low hatchability in which larger between‐treatment differences may be expected.

4. The results of hatchability studies should always be subjected to tests of statistical significance.

5. There is a strong case for studying continuous variates in the laboratory before proceeding to large‐scale hatchability studies.     

Whitening of brown shelled eggs: Individual variation and relationships with age,fearfulness, oviposition interval and stress

1. Fearfulness, shell colour, incidence and degree of shell whitening and the interval between ovipositions were studied in two populations of 30 brown egg laying hens with family histories of a low or a high incidence of egg shell whitening.

2. Hens of the population with the high incidence of whitening appeared to be more fearful than hens of the population with the low incidence of whitening.

3. Brown colouration of the egg shell and the incidence and degree of shell whitening declined as the hens aged.

4. Brown colouration and egg shell whitening were most pronounced on the blunt ends of the eggs.

5. A large part of the variation in egg shell whitening was attributable to the individual (hen) component of variance.

6. Differences in egg shell whitening, between the two populations, were detectable throughout the 26 weeks of the experiment.

7. Oviposition intervals were similar for normal and coated eggs when birds were not exposed to disturbance.

8. Disturbance of hens increased oviposition intervals and the incidence and degree of shell whitening, to a similar extent, in both populations.

9. It is concluded that stress‐related egg retention is not the sole factor responsible for abnormal egg shell whitening. Shell whitening may occur as a consequence of the premature termination of shell pigmentation as well as a consequence of the retardation of oviposition which occurs when hens are disturbed.     

Effect of feeding regimen and lighting pattern on the performance of broiler chickens in the hot,humid tropics

1. A food restriction study in conjunction with light control was conducted with commercial broiler chicks in a tropical environment.

2. Chicks on treatments 1 and 2 were fed continuously while those on treatments 3 and 4 were fed during the day (from 06.00 h to 18.00 h) and night (from 18.00 h to 06.00 h) respectively. Chicks on treatment 1 received only natural light during the day, while those on treatments 2, 3 and 4 received supplementary lighting during the night in addition to natural light during the day.

3. Food consumption by birds on treatment 2 was significantly higher at 56 days of age, followed by birds on treatments 1, 4 and 3.

4. The pattern of body weight gains was similar to the order of food consumption.

5. Efficiency of food utilisation was poorest for birds on treatment 2.

6. Mortality rates were not influenced significantly by the feeding regimen and lighting pattern.

7. Dressing percentage and proportion of abdominal fat were greatest for birds on treatment 2.     

The performance of cross‐bred hens given free choice feeding of whole grains and a concentrate mixture and the influence of source of xanthophylls on yolk colour

1. Cross‐bred hens were offered, from 25 to 73 weeks of age, diets based on either wheat or barley in the form of either a mash or as whole grains plus a concentrate mixture; four sources of xanthophylls were also compared.

2. Wheat reduced food intake by 8%, increased efficiency of food conversion and live‐weight gain while barley increased litter moisture content, and, during the first half of the laying year decreased egg production by 3.3% and yolk colour by 4%.

3. Hens offered whole grains ate 11% less food, converted food into eggs more efficiently, were heavier and laid larger eggs than those given the mash diets.

4. With whole grains yolk colour was less than with mash diets during the first 24 weeks of lay but this was reversed during the last 24 weeks of lay.

5. Either canthaxanthin or citranaxanthin or β‐apo‐8'‐carotenoic acid ethyl ester plus canthaxanthin in diets containing lucerne meal produced eggs with acceptable yolk colours.     

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.     

Explanted embryo culture: In vitro and in ovo techniques for domestic fowl

1. Embryos of the domestic fowl (72 h old) have been explanted into shell‐less cultures or ‘surrogate’ eggshells, in order to investigate the possibility of rearing these embryos to hatching.

2. Rocking embryo cultures during the first half of incubation enhanced embryo growth.

3. Embryos explanted into ‘surrogate’ eggshells of either other individuals or other species have been successfully ‘hatched’.

4. A normal chorioallantois is formed in these surrogate eggshells. This enables a functional albumen sac to form and eggshell resorption to be achieved.

5. Embryos grown in ‘surrogate’ eggshells are slightly smaller than controls but otherwise normal.

6. The technique provides opportunities for genetic engineering experiments.     

Genotypic differences in speed and magnitude of response to ahemeral lighting

1. The paper compares between three genetically different lines in their egg weight and shell thickness response to a 28‐h cycle.

2. The response in shell thickness to ahemeral lighting was more rapid (2.2 d) than for egg weight (4.2 d).

3. Differences between genotypes were evident in both the speed and magnitude of response.

4. Overall, egg weight and shell thickness on the 28‐h cycle were 7% and 8% greater than on 24 h.

5. The allometric increase indicates that the increase in shell weight was on average 14% more than the increase in egg weight.     

Effect of cuticle removal on the water vapour conductance of egg shells of several species of domestic bird

1. The effect of egg shell cuticle removal, using a 14.7 mM solution of sodium hypochlorite, on the water vapour conductance of egg shells was studied in 5 species of domestic bird.

2. The water vapour conductance of fowl and Muscovy duck egg shells was not affected by the treatment.

3. Cuticle removal increased the conductance of turkey and goose shells, particularly those already relatively porous to water vapour.

4. Removal of cuticles from domestic duck egg shells increased water vapour conductance. In this case the effect was most marked for eggs with lower initial conductances.

5. The differing patterns of resistance to water vapour loss associated with egg shell cuticle are related to the ultrastructure of the cuticle itself, especially the number and size of cuticular fissures.

6. The results suggest that egg shell cuticle is a component in a series of resistances associated with the egg shell and that the use of Fick's Law is insufficient to explain water vapour diffusion across the shell.

7. Embryo survival may be improved by cuticle removal, though this may be limited to those species in which the cuticle restricts water vapour loss in initially low conductance egg shells.     

Comparison of nutritive values of groundnut oil cake and Niger oil cake for laying pullets

1. The nutritive value of Niger oil cake (Guizotia abyssinica, Cass.) as a protein supplement for layers’ diets has been assessed.

2. Replacing groundnut oil cake (GNC) by Niger oil cake (NC) on an isonitrogenous basis, did not affect egg production, egg weight or the amount of food required per dozen eggs.

3. The percentage retention of nitrogen from diets containing 30% GNC or 30% NC was similar.

4. The ME value of NC used was 3025 kcal/kg.

5. It is concluded that NC can replace GNC in layers’ diets.