Studies on the effect of lysine and methionine supplementation of a high‐protein maize‐soyabean diet and of a low‐protein barley‐white fish meal diet on the performance of caged layers     

N. Jackson  E. Squance  D. W. F. Shannon 《British poultry science》1967,8(1):43-53

Selected literature relating to the amino acid supplementation of layers’ diets is reviewed and the results of two experiments are presented.

In the first experiment a basal soyabean meal diet (14.3 per cent crude protein) was supplemented with L‐lysine and DL‐methionine, singly and together. Supplementation of the basal soyabean diet with the amino acids caused no significant effects on egg production, mean and total egg weight or food conversion efficiency. None of the soyabean diets proved as satisfactory for egg production or food conversion efficiency as a fish meal control diet (16.9 per cent crude protein).

In the second experiment the effect of adding 0.1 per cent each of L‐lysine and DL‐methionine or 0.2 per cent each of l‐lysine and DL‐methionine to a low fish meal diet (2.5 per cent fish meal) was examined. The addition of 0.2 per cent of each amino acid caused an increase in egg production.

Mean egg weight was improved by the addition of amino acids at both levels although this effect was not statistically significant. Comparison of the low fish meal diets with a fishmeal control diet (10 per cent fishmeal) showed that at the 0.2 per cent addition of amino acids, egg production, total egg weight and food conversion efficiency were better than on the 10 per cent fish meal control diet.

Two breeds, light and medium hybrids were used in both experiments.

The results are discussed with reference to their practical significance.  相似文献   

Egg production of light and medium hybrids given diets varying in energy level during the chick,rearing and laying stages     

W. Bolton  R. Blair  D. W. Knight 《British poultry science》1970,11(1):53-66

A total of 1000 birds, one‐half of which were light and the other half medium hybrids, were given diets containing either high or low levels of metabolisable energy ad libitum during the chick (0.6 weeks), rearing (6–16 weeks), early laying (first 8 months) and late laying (last 4 months) stages.

The medium hybrids ate more and were heavier than the lighter hybrids at all stages. More eggs were laid by the light than by the medium hybrids but the latter laid larger eggs so that the total weight of eggs laid did not differ significantly between the two groups.

Medium hybrids given a low‐energy chick diet laid more eggs subsequently than those given a high‐energy chick diet, while the opposite result was obtained for the light hybrids.

Birds given a low‐energy rearing diet were lighter at 16 weeks and subsequently laid more eggs than birds reared on a high‐energy diet.

During the first part of the laying period consumption of the low‐energy diet was greater than that of the high‐energy diet, but the level and efficiency of egg production were the same for both dietary treatments. Mortality during lay was not significantly affected by dietary treatment or breed.  相似文献   

The use of rapeseed meals and a mustard seed meal as a protein source in diets for laying pullets     

A. G. Marangos  R. Hill 《British poultry science》1976,17(6):643-653

1. Three experiments with laying pullets were carried out in which rapeseed meals (B. napus and B. campestris) and a mustard seed meal (B. juncea) formed 12% of the diet.

2. Dietary rapeseed had no effect on the onset of lay when fed from 17 weeks of age but caused a delay when fed from 10 weeks of age: changing to a control soyabean diet for the laying period resulted in normal egg production.

3. Diets containing B. napus but not B. campestris consistently depressed egg production and reduced egg weight in one experiment. Mustard seed meal did not affect performance.

4. Significant number of eggs with a “fishy” taint were laid by brown‐egged birds fed on a diet containing rapeseed.

5. Thyroids of birds fed on rapeseed meal diets during the laying period were significantly heavier than those of birds fed on diets containing mustard seed or soyabean.

6. The enlargement of the thyroid gland is probably related to the oxazolidinethione content of the rapeseed.  相似文献   

Magnesium tolerance of the growing and laying chicken     

G. W. McWard 《British poultry science》1967,8(2):91-99

The effects of various levels of magnesium in growing and laying rations on growth and laying performance were studied. Levels of magnesium in the growing and laying rations were 0.36, 0.59, 1.06 and 1.83 per cent and 0.48, 0.70, 1.20 and 1.96 per cent respectively.

Only the growing ration containing 1.83 per cent magnesium significantly reduced growth, percentage bone ash and food utilisation during the growing phase (9–20 weeks). In the laying phase (20–40 weeks) significantly greater gains in body weight and percentage bone ash were produced by the birds which had received the growing ration containing 1.83 per cent magnesium.

The magnesium content of the growing rations had no effect on rate of lay, egg weight or egg shell thickness.

Hens fed the laying ration containing 1.96 per cent magnesium gained less body weight, laid fewer and lighter eggs and utilised their food less efficiently than those fed other levels of magnesium.

Egg production and food required per dozen eggs were poorer with the ration containing 1.20 per cent magnesium, but were not statistically different from the rations containing 0.48 or 0.70 per cent magnesium.

Eggs with thinner shells were produced by hens fed the 1.96 per cent magnesium ration at 34 weeks of age than were produced by those fed the 0.48 or 0.70 per cent magnesium rations.  相似文献   

Efficiency of egg production of three types of caged layers fed diets containing maize, oats or barley as the main cereal ingredient     

W O Brown  R W Hale 《British poultry science》1965,6(2):119-124

The results of two similar experiments, each using 204 pullets in cages, are presented. In each experiment, a type of light commercial hybrid, heavier commercial hybrids and Brown Leghorn×Light Sussex cross‐breds were compared, in factorial design, on diets containing either 65 per cent barley, 55 per cent maize or 35 per cent oats and 15 per cent bran. Individual records of egg production, egg weight, food conversion and body weight were kept for eight 28‐day periods, starting when the pullets were in full production.

There were no significant differences in egg production between diets but in both experiments a significantly improved food conversion ratio was obtained on the high maize diets, which also gave the highest level of energy consumption.

Most breed differences were not significant but in Experiment 1 the crossbreds produced significantly fewer eggs than the hybrids and in Experiment 2 the light hybrids gave a significantly better food conversion ratio than the two heavier types. The crossbred pullets consumed the most energy in both experiments and in Experiment 1 had significantly the worst energetic efficiency of egg production.

There were no significant interactions between type of pullet and type of diet in either experiment. Thus there were no indications that, at the energy levels investigated, favourable effects may be expected from the feeding of higher energy diets to the lighter hybrid type pullet.

The practical significance of feeding a high barley diet is discussed.  相似文献   

Sweet white Lupinus Albus (cv buttercup) as a feedstuff for layers     

J. J. Prinsloo  G. A. Smith  W. Rode 《British poultry science》1992,33(3):525-530

1. An experiment was conducted with laying hens to determine to what extent sweet white lupins (Lupinus albus, cv Buttercup) could be used as a protein source in their diets.

2. Twenty five individually caged 20 week‐old Hisex laying hens were used per treatment. The hens were housed in a convection house for the duration of the study which lasted 52 weeks. Two diets were formulated, one containing 300 g sweet lupins/kg and the other containing sunflower oil cake and fish meal as protein sources. These diets were blended to obtain seven diets with lupin inclusion rates of 0, 50, 100, 150, 200, 250 and 300 g/k.

3. Results indicated that up to 300 g lupins/kg diet can be fed to Hisex laying hens without a significant effect on egg production, egg mass, efficiency of food utilisation, egg shell thickness, Haugh units or yolk colour. Food intake was however, significantly (P<0.05) positively correlated with lupin inclusion rates.  相似文献   

Arginine--lysine interrelationships in the nutrition of broiler breeder pullets during the developmental period     

J R Couch  W W Abbott 《British poultry science》1974,15(5):467-479

Pullets were fed on diets containing various concentrations of lysine and arginine from 7 to 18 or 20 weeks. Thereafter a conventional layers' diet was fed and egg productivity measured—in the first two experiments for ten, and the third for six 28‐d periods. Pullets were also fed on a standard growers' type diet on a “skip‐a‐day” or on a 20% restriction basis in the third study.

Growth and age at sexual maturation were directly related to the lysine content of the diet and to a lesser extent to the arginine content. Pullets fed on diets with the lower concentrations of lysine and arginine required less food during the growing period and matured later than those fed on a complete diet ad libitum. They also laid more eggs and required less food to produce a dozen eggs. Higher egg production was obtained in the third experiment with low concentrations of lysine and arginine than with the “skip‐a‐day” or the restricted feeding programmes. Pullets fed on the normal grower diet ad libitum produced the smallest eggs in the first and third experiments with no difference in egg size in the second experiment. Pullets maintained on the “skip‐a‐day” or the restricted feeding programme also had a larger egg size than the control group fed on the same diet on an ad libitum basis.

An ingredient effect was observed in the third experiment. Of two diets containing identical calculated values of lysine and arginine, the one containing distillers' dried grains with solubles was superior to the one with soybean meal as regards weight at 20 weeks of age, amount of food consumed during the period 6 to 18 weeks of age and percentage egg production. It is possible that the soybean meal contained a better balance of amino acids than did distillers' dried grains with solubles which resulted in a significant increase in body weight at 20 weeks of age and a subsequent lower level of egg production. These data indicate that it would be best to use ingredients with an imbalance of amino acids in the protein as sources of lysine and arginine in pullet grower diets.

There were no differences in the mortality of the birds during the laying period which could be related to dietary treatment during the pullet growing period.  相似文献   

Comparison of laying rations with and without animal protein at the Canadian Random Sample Egg Production Test     

J R Aitken  J Biely  N Nikolaiczuk  A R Robblee  S J Slinger 《British poultry science》1969,10(3):247-253

For a number of years, the laying ration fed to the hens at the Canadian Random Sample Egg Production Test has contained foodstuffs of animal origin to the extent of 3 per cent meat meal, 2 per cent fish meal, 1 per cent dried whey and 2 per cent tallow. Recently, over a period of 2 years, this ration was compared with a modification in which all of the animal products except tallow were removed. The proportions of the remaining ingredients in the modified diet were adjusted to keep protein, energy, calcium and phosphorus levels comparable in the two rations.

In the first test year, the modified diet was slightly superior to the control diet in terms of egg numbers, egg weight and egg quality. In the second year, there were no significant differences in these traits between diets. Although 17 strains were tested in the first year, and 14 in the second, no significant strain × ration interactions occurred in any performance trait.

These trials provided no evidence that the laying hen responds to unknown factors contained in animal products. There was also no evidence that the removal of animal products adversely affected protein quality, although dietary protein levels may not have been low enough to reveal such a change.  相似文献   

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     

H. Karunajeewa 《British poultry science》1978,19(6):699-708

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.  相似文献   

Effects of battery gage shape and dietary energy regulation on the performance of laying hens offered diets containing dried poultry manure     

D. J. W. Lee  W. Bolton  W. A. Dewar 《British poultry science》1978,19(5):607-622

1. About 3000 medium‐weight hybrid chicks were used in a factorial experiment involving two “chick” treatments: diets containing 0 and 50 g dried poultry manure (DPM)/kg; three “grower” treatments, diets with and without 50 g DPM/kg given ad libitum and regulated amounts of the diet with DPM; five “layer” treatments: diets with 0, 100 or 200 g DPM/kg given ad libitum and regulated amounts of diets containing 110 and 220 g DPM/kg and two shapes of layer cages: deep (conventional) and shallow.

2. Chick diets had no significant effects on rearing or subsequent laying performance.

3. Food‐regulated pullets were 7% lighter than pullets given the DPM diet ad libitum at 18 weeks but consumed 12.5% less food; growing treatments had no significant effect on subsequent egg production.

4. Hens housed in shallow cages laid 10.3 eggs/bird‐housed more than those in deep cages, produced 3.8% greater egg mass, consumed 2.7% less food and produced fewer damaged (cracked, broken and hair‐cracked) eggs (P< 0.001).

5. DPM‐containing layer diets had no adverse effects on egg production, or mortality; with 100 g DPM/kg efficiency of food conversion (EFC) was better than with 0 or 200 g/kg (P< 0.001).

6. Reduction of the energy intake of L110R and L220R hens with diets containing 110 and 220 g DPM/kg by 8.2 and 9.0% respectively, reduced the number of eggs laid/hen‐housed by 6 and 10.7 but improved the EFG (P< 0.001); there was no significant interaction between cage shape and energy regulation.  相似文献   

The effect of maize and maize oil on egg weight     

D. G. Edwards  T. R. Morris 《British poultry science》1967,8(3):163-168

In two short‐term experiments involving about 1500 laying pullets it was confirmed that the direct substitution of maize for wheat in a laying diet leads to a small but significant increase in egg weight.

It was further shown that when oat hulls were added to a diet containing 55 per cent maize to make it isocaloric with a diet containing 55 per cent wheat, there was still a significant improvement in egg weight with the maize diet. The addition of 2 ‐5 per cent and 5 per cent maize oil to a 55 per cent wheat diet resulted in increases in mean egg weight of 0.7 g. and 1.3 g. respectively. The same response to 2 .5 per cent maize oil was obtained when oat hulls were added to make the diet isocaloric with the basal diet.

It is concluded that maize has an effect on egg weight which is not attributable to the differences in dietary energy normally associated with the substitution of one cereal for another in practical diets. The effect is associated specifically with the oil content of the maize.  相似文献   

Calcium and phosphorus levels in the diet of laying birds     

F. J. Dudley  G. J. Pickering 《British poultry science》1966,7(2):83-90

Two hatches of crossbred pullet chicks were brooded and reared to 18 weeks of age on diets which conformed to the recommendations of the National Research Council (N.R.C.) of America for calcium and phosphorus. The pullets of each hatch were then divided at random into six laying groups. Three groups were fed diets containing 2.25, 3.14 and 5.0 per cent respectively of calcium without supplementary phosphorus and the other three groups were fed diets of the same graded calcium levels but with supplementary phosphorus to give a total inorganic phosphorus content of 0.45 per cent. When the rate of egg production in the groups receiving 2.25 per cent calcium exceeded 70 per cent an ad libitum supply of limestone grit was provided and the intake recorded. Over the twelve months of lay this resulted in an average total dietary intake level of nearly 2.65 per cent calcium.

Egg yield was not significantly influenced by the diets, except that the production of birds fed on the diet containing 5 per cent calcium without supplementary phosphorus was significantly depressed. Food intake was not adversely affected by the higher levels of ground limestone; in fact, there was a positive regression of food consumption on the percentage of calcium in the diet. Because of the greater food intake and the lower egg production, food consumed per dozen eggs and cost of food per dozen eggs were higher in the groups receiving 5 per cent dietary calcium without phosphorus supplementation, compared with groups which received lower dietary levels of calcium. There were, however, no significant differences between the various groups in income or in the margin of income over costs, per bird or per dozen eggs.

The data on egg grading showed that over the two experiments and at all levels of calcium there was no evidence of any influence of phosphorus on the combined percentage of large and standard eggs. The average percentage for the two diets with the 5 per cent level of calcium was significantly greater than the combined average for all the other diets.

The average percentage of cracked eggs for the groups with diets containing 5 per cent calcium was 9.4 per cent compared with an average of 11.1 per cent for all the other diets, but the difference was not significant.

The results suggest that there is no economic advantage in raising the calcium content of the basal diet used in these experiments beyond the level of 3.14 per cent and that at this level there appears to be no need with this basal diet to supplement the phosphorus content.  相似文献   

A comparative study of energy utilisation by the laying hen from diets containing a high proportion of fat and diets made up mainly from carbohydrate sources     

J J Waring  R F Addison  W O Brown 《British poultry science》1968,9(1):79-86

An experiment was carried out in which laying hens were fed diets containing about 30 per cent tallow at three protein levels. Productive performances of hens on these diets were compared with those of hens fed either a diet containing 15 per cent arachis oil, a diet containing 15 per cent sucrose or a conventional cereal‐based control diet.

It was found that the best performance was obtained with hens fed the control diet. Gross energetic efficiency of egg production was slightly lower in the birds fed the diets containing arachis or sucrose. It appeared that the lower efficiency was due to the higher mean body weight of birds on these diets. Egg size was significantly increased by feeding the diet containing arachis oil.

Performance of hens given diets containing tallow was unsatisfactory. For each diet egg production was significantly less than that recorded for the control diet and the gross energetic efficiency of egg production was much lower than that on the control diet.  相似文献   

Dietary rapeseed meal and the incidence of tainted eggs     

N. D. Overfield  H. A. Elson 《British poultry science》1975,16(2):213-217

1. Incorporating 0, 3, 6 or 9% rapeseed meal in the diet of brown‐egg laying birds for 28 d resulted in the production of 0, 1.2, 19.3 and 20.9% tainted eggs respectively, the first tainted eggs being laid on the fifth day.

2. During the second and third weeks the incidence of tainted eggs exceeded 20% but fell to 11.4% during the final week.

3. Omission of the rapeseed meal from the diets halted the production of tainted eggs.

4. Neither egg production nor the health of the birds was adversely affected by the treatments.

5. The taint was described as “ fishy ” or “ crabby ” and was distinctive, but the source was not identified.  相似文献   

A study of the effect of variation in the calorie‐protein ratio of a medium energy diet and a high energy diet containing sucrose on the efficiency of egg production in caged layers     

W. O. Brown  J. J. Waring  E. Squance 《British poultry science》1965,6(1):59-66

Literature pertaining to the variation in the protein content of layers’ diets is discussed and the lack of information on the effect of calorie‐protein ratio on food conversion is mentioned. The experiment described in the present paper was designed to test the effect of variations in calorie‐protein ratio on food conversion on a diet of high energy content (1340 k cal/lb.) based on sucrose supplementation and on a medium energy diet (1160 k cal/lb.). At the same time three types of pullet, Thornber 606, Thornber 404 and Light Sussex x Brown Leghorn pullets were compared on the two types of diet, each being fed at three nominal protein levels of 13, 15 and 17 per cent giving a total of eighteen treatments. The pullets were individually recorded for egg production, egg weight and food consumption. Meta‐bolisable energy crude protein determinations were carried out on each of the six diets employed and the actual calorie‐protein ratios calculated.

There was no significant effect on egg production when the calorie‐protein ratio of the diet was raised from 69 (i.e. k cal M.E./lb. per 1 per cent protein) to 90 but an increase to 103 reduced production and egg weight. It was found that maximum efficiency of food conversion was realised at ratios of 76 to 78.

The efficiency of conversion of dietary energy was unaffected by energy concentration in the diet.

The lightweight hybrid (Thornber 606) produced eggs more efficiently than either the Thornber 404 or the crossbred type.  相似文献   

Effect of feeding low lysine starters and developers on growth,sexual maturity and subsequent performance of broiler breeder pullets 1     

J. R. Couch  J. H. Trammell 《British poultry science》1970,11(4):489-499

Pullets that were fed diets containing 0.53 per cent and 0.42 per cent lysine grew at a slower rate and matured later than those that were given adequate amount of lysine. The latter pullets converted their food more efficiently than did the restricted pullets with the exception of the group fed the ration containing 0.53 per cent lysine for the first 12 weeks. The restricted pullets consumed less food during the growing period. A smaller bird was produced on less food. The restricted pullets were also lighter than the control pullets at the end of the laying season. A saving in food costs is indicated because the smaller hen would require less food for maintenance.

There was a higher mortality in the pullets fed a ration containing 0.53 per cent lysine during the growing period. The mortality in the group fed the ration containing 0.42 per cent lysine from 7 to 22 weeks of age was the same as that of the control. There were no differences in mortality during the laying season that could be related to methods of rearing the pullets.

During the laying season, the highest rate of lay was obtained from hens which had been fed the ration containing 0.42 per cent lysine from 7 to 22 weeks of age. Hens fed on the ration containing 0.53 per cent lysine from o to 4, 8 or 12 weeks of age showed no improvement in rate of lay as compared with controls.

Hens fed the ration containing 0.42 per cent lysine from 7 to 22 weeks laid fewer small eggs at the beginning of the laying season than did hens receiving adequate amounts of lysine throughout or fed the ration containing 0.53 per cent lysine from o to 4, 8 or 12 weeks. The hens fed the latter ration laid smaller eggs throughout the laying season.

No differences were found between the fertility, hatchability or embryonic mortality of eggs obtained from hens fed on lysine deficient diets during growth and those fed on diets adequate in lysine.  相似文献   

Some effects of changing protein levels during the pullet laying year     

C. Fisher  T. R. Morris 《British poultry science》1967,8(2):153-161

Three diets containing 12, 14 and 16 per cent crude protein were fed to laying pullets from 23 to 63 weeks of age. The laying year was divided into three periods of 10, 15 and 15 weeks to examine the effect of feeding these diets at different stages of lay. Eighteen treatments were used, representing all possible combinations of three diets in the first period, three diets in the second period and two diets (16 and 12 per cent) in the third period. Two groups of 75 pullets were allocated to each treatment.

In each period the diet had a significant effect on the rate of lay, egg output (g./day) showed a linear regression on protein intake. There was no indication that the amount of protein needed to maximise egg output was any less in one period than another, although the level of maximum output varied substantially as the year progressed.

Where the feeding of an inadequate level of protein in one period was followed by a higher level in the next, liveweight showed a marked recovery but there was little evidence of compensatory egg production. When the protein of the diet was reduced from 16 to 12 per cent, rate of lay fell sharply to a level below that of birds which had received the 12 per cent protein diet throughout.  相似文献   

An experimental study of the utilisation, by the laying hen, of dietary energy partially supplied as animal fat     

N Jackson  H R Kirkpatrick  R B Fulton 《British poultry science》1969,10(2):115-126

Experiments were carried out at two centres in which laying hens were fed diets containing up to 28.25 per cent tallow and in which an attempt was made to maintain a fairly constant calorie : protein ratio. The most satisfactory production was obtained on a diet containing 3.5 per cent added fat in one experiment and 7.5 per cent added fat in the other experiment. Food conversion efficiency (kg food/kg eggs) increased with increasing dietary fat content.

The efficiency of ME utilisation (Mcal/kg egg) decreased with increasing dietary ME content. The data indicate that at the higher levels of fat addition the net utilisation of ME was decreased.

In both experiments mean egg weight was increased by the addition of tallow to the diet whilst at the highest level of addition there was a very high mortality.  相似文献   

The protein requirements of two strains of laying pullets     

E. Sharpe  T. R. Morris 《British poultry science》1965,6(1):7-13

Diets with 16.5, 14.5, 12.5 and 10.5 per cent protein and 2765 k cal. metabolisable energy per kg. and a fifth diet containing 10.5 per cent protein and 2165 k cal. M.E./kg. were fed to Rhode Island Red x Light Sussex pullets and to “hybrid” pullets which weighed 33 per cent less and produced 20 per cent more eggs. Both strains had protein requirements of the order of 20 g./bird/day. It is possible that the assumed higher requirement of the “hybrid” pullets for productive purposes was offset by a smaller requirement for maintenance and growth. Expressed as a percentage of a 2765 k cal. diet, the small strain required at least 16.5 per cent protein and the large strain no more than 12.5 per cent protein for maximum performance. Both strains performed well on the 2165 k cal., 10.5 per cent protein diet, illustrating that high energy diets are not essential for small strains of pullets.

Egg size was reduced by protein restriction in the heavy strain but not in the light strain. On isocaloric diets the light strain consumed more food only at the lowest protein level whereas the heavy strain tended to eat progressively more as the protein was reduced from 16.5 to 12.5 per cent. When offered the low energy diet both strains ate more food, but substantially fewer calories, than when given diets of 2765 k cal. M.E./kg. Protein restriction had a marked effect in reducing live‐weight gains. Energy level of the diet had a large effect on weight gain and also on fat deposition in the carcass.

The greatest differences in performance due to diet did not occur at the time of maximum egg output. The evidence indicates that a diet which is too low in protein to support peak egg production will also fail to support normal egg production at any later stage of the laying year.  相似文献   

The effects on egg production and egg composition of adding supplements of amino acids and/or urea or dried auto‐claved poultry manure to a low‐protein layer diet     

R. Blair  D. J. W. Lee 《British poultry science》1973,14(1):9-16

Thirty‐five laying hens of a medium‐weight hybrid strain, aged 10 months, were given a basal diet containing 11.5% protein or the same diet supplemented with 1.54% essential amino acids and/or with two sources of nitrogen for the synthesis of non‐essential amino acids (1.15% urea or 9.7% dried autoclaved poultry manure) for an 8‐week period.

Egg production, food intake, food conversion efficiency, the gross efficiency of nitrogen conversion and the ability of hens to maintain body weight were improved by supplementation with essential amino acids (P < 0.05 or P < 0.01). Supplementation with dried autoclaved poultry manure raised food intake, total egg mass and mean egg weight (P < 0.05), but supplementation with urea alone did not result in significantly higher egg production, perhaps because it failed to increase food intake. Supplementation with essential amino acids and urea to give the equivalent of 16% protein did not result in significantly higher egg production than that obtained with urea alone. The smallest eggs were produced by hens fed on the diet supplemented with urea, and the largest by those fed on the diet supplemented with dried manure (P < 0.001).

The gross composition of eggs was not influenced significantly by dietary treatment but albumen quality was significantly lower on the basal diet and higher on the supplemented diets (P < 0.001). It was highest in eggs from hens fed on the diet supplemented with urea alone.  相似文献