Cottonseed Meal Diets Improve Body Weight Uniformity in Broiler Breeder Pullets

Due to its low nutrient density, cottonseed meal (CSM) may be a potential alternative feed ingredient for soybean meal (SBM) in broiler breeder pullet diets to improve flock BW uniformity. A major concern when utilizing CSM in poultry diets, however, is the presence of gossypol. It was determined in an initial experiment that when broiler breeder hens are fed a diet containing CSM, gossypol accumulates in the liver. When CSM is removed from the diet, however, hepatic gossypol levels dissipate within a few weeks. In a subsequent study, in order to achieve the breeder guideline ideal weight, broiler breeder pullets reared with a diet containing CSM from 2 to 18 wk of age had to be fed a larger amount than birds consuming a standard SBM diet. The CV of bird weight was significantly lower during the rearing period for birds reared with the corn and CSM diet. This difference in uniformity was maintained as the hens entered the breeding period. Egg weight, hatchability, and fertility were equivalent for hens reared with a diet containing CSM and those reared with a standard diet throughout the growing period. The results suggest that broiler breeder pullets reared on a diet containing CSM as the major protein source have improved flock BW uniformity and normal subsequent reproductive performance.     

Choice feeding of the egg‐type pullet

1. Egg‐type pullets from 43 to 127 d of age were fed either a high‐protein concentrate (493 g/kg), a protein concentrate (323 g/kg) or a grower diet, together with either whole wheat or whole barley. Further birds received a complete diet and had no choice.

2. Eighty‐four point six, 69.5 and 31.4% respectively of the food consumed by the birds which received the high‐protein concentrate, protein concentrate or grower diet with wheat consisted of the whole cereal. The corresponding figures for the birds which received barley were 73.9, 41.3 and 10.9% respectively.

3. There were no significant differences in rate of food intake or growth between choice‐fed birds receiving whole wheat and the complete diet‐fed birds with no choice.     

Use of dried papaya skin in the diet of growing pullets.

1. The chemical composition of dried papaya (Carica papaya) skin (DPS) was determined and the effect of diets containing different concentrations of this ingredient (0, 30, 60 and 90 g/kg) was studied using growing pullets as experimental animals. 2. Crude protein concentration was determined to be 229 g/kg and metabolisable energy content was estimated to be 6.4 MJ/kg. 3. Use of DPS in the diet up to 90 g/kg did not produce any significant difference in weight gain, food intake, food conversion and protein efficiency when compared with birds that received the control diet. 4. Survivability of growing pullets fed on DPS was 100%, as in the control group. 5. It was concluded that DPS can safely be used up to 90 g/kg in the diet of growing pullets.     

Performance of broiler breeder pullets as influenced by composition of grower and layer diets 1

An experiment was conducted to determine the influence of three grower systems upon the subsequent performance of broiler type breeder pullets. The grower systems were full feeding a 10 per cent protein diet, full feeding a 16 per cent protein diet, and a skip‐a‐day feeding of the 16 per cent diet. One‐third of the pullets fed according to each of the feeding programmes were fed on each of three different layer diets. The use of the low protein and the skip‐a‐day feeding resulted in delaying age at sexual maturity. Total rate of egg production was not affected by the grower diet; however, the number of “ settable “ eggs was increased when maturity was delayed.

Performance of the laying hens was not influenced by the composition of the layer diet. Fertility or hatchability was not influenced by composition of either the grower or layer diet. These data would indicate that the low protein diet or the skip‐a‐day feeding system can be effectively used with feeding replacement broiler type birds.     

Effects of constant environmental temperatures on the performance of laying pullets

1. Two experiments are described in which laying pullets maintained at constant temperatures were fed a range of diets with a view to defining optimum combinations of temperature and nutrient intake. 2. In the first experiment, all combinations of 6 temperatures (15 degrees, 18 degrees, 21 degrees, 24 degrees, 27 degrees and 30 degrees C) 9 diets (three protein concentrations and three energy contents) and two stocks were tested for 34 weeks using 4320 pullets. In experiment 2, all combinations of three rearing temperatures, three laying temperatures (18 degrees, 22.5 degrees and 27 degrees C) three diets (protein concentration) and two stocks were tested for 61 weeks using 2160 pullets. 3. As anticipated, higher dietary protein concentrations were needed to maintain egg output at higher temperatures. If diets suplying adequate amino acid intakes were provided, egg output was unaffected by temperatures in the range 15 degrees to 27 degrees C although, at the highest temperature, egg weight was slightly reduced and rate of lay (particularly in the later part of the laying year) was increased. At 30 degrees C, egg output was depressed whichever diet was fed. 4. Dietary energy content had small but significant effects on egg weight and egg output but did not interact with temperature. It was not possible to maintain egg weight or egg output at 30 degrees C by feeding a high energy, high protein diet. 5. Estimated heat output of the birds increased during the course of the experiment at the lower temperatures but decreased with time at 30 degrees C. Feather loss occurred earlier at the lower temperatures and this is interpreted as an effect of temperature on the timing of the annual moult, which also accounts for the better persistency of lay observed at 27 degrees C.     

An assessment of the optimal range of dietary sodium for inducing a pause in laying.

Laying hens were fed on a diet containing 0-9 g sodium/kg until 34 weeks of age, then groups were fed on diets containing 0-2, 0-3,0-4, 0-5, 0-6 or 0-9 g sodium/kg for 16 weeks before that containing 0-9 g sodium/kg was reintroduced for all birds. 2. Egg production and food consumption were depressed by the low-sodium diets in proportion to the dietary sodium content. 3. Birds receiving 0-3 to 0-6 g sodium/kg diet lost weight initially but subsequently gained weight; birds receiving 0-2 sodium/kg diet lost weight continouosly. 4. In birds receiving 0-2 g sodium/kg diet, the reproductive organs were completely regressed, whereas these organs resembled those of point-of-lay pullets in birds fed on 0-3 or 0-4 g sodium/kg. 5. When the control diet was reintroduced, birds which had received the low-sodium diets resumed normal egg production and food consumption and regained body weight. 6. The optimal range of dietary sodium for inducing a pause in egg laying is 0-3 to 0-4 g/kg.     

The effect of dietary energy level on the voluntary calorie intake of laying birds

This paper summarises evidence taken from the literature to show the effect of dietary energy level on the voluntary food intake of laying birds. Although groups of pullets offered different diets tend to adjust consumption so as to maintain the same calorie intake, this adjustment is imperfect in the majority of cases. Thus birds fed high energy diets usually “over‐consume” calories and gain more in weight than birds fed lower energy diets. The degree of over‐consumption observed when a particular strain is offered a range of diets of differing energy content is correlated with the characteristic calorie intake of that strain (r = 0.667). Strains with characteristically high energy intakes adjust their food consumption to compensate for differences in energy content of the diet less efficiently than the small strains which have characteristically low calorie intakes.

From the relationships demonstrated, a formula is developed which predicts the expected daily calorie intake for any level of dietary energy, given a knowledge of the calorie intake of the strain when fed some standard diet. The use of this information in the formulation of diets designed to minimise the cost of feeding is illustrated by an example.     

Influence of dietary charcoal on ochratoxin A toxicity in Leghorn chicks.

The ability of activated charcoal to adsorb ochratoxin A (OA) in vitro and to reduce the toxic effects of OA in vivo when added to the diet of growing Leghorn chicks was studied. Activated charcoal (50 mg) was able to adsorb 90% of the OA (150 micrograms) contained in 10 mL of citrate-phosphate buffer (pH 7.0). When 2 g of a complete chick diet were mixed with OA in buffer, it adsorbed 66% of the OA, while addition of 50 mg of charcoal to this mixture further reduced the concentration of OA to 11.8% of the control, an additional 65% compared to the diet alone. In the first of two feeding studies, charcoal addition of up to 10,000 parts per million (ppm) to diets (6.7% tallow) containing 9.93 mumol (4 ppm) OA kg-1 diet had no effect on OA toxicity. Feed consumption and weight gain, however, were reduced 10 and 20%, respectively, in chicks fed diets which contained 10,000 ppm of charcoal compared to those fed no charcoal. In the second study, reducing dietary tallow to 2% did not alter the effects of OA or charcoal on weight gain and feed to gain ratio, but birds fed OA with 10,000 ppm charcoal had an 8.5% increase in feed consumption. An additional management problem was associated with the propensity of charcoal to blacken the feed, the birds and their environment. Addition of charcoal to OA contaminated diets appeared to be an ineffective method for reducing the toxic effects of OA in growing chicks.     

Metabolism of some essential minerals in ponies fed high levels of aluminum

The effect of dietary aluminum on the absorption, retention and pathways of excretion of calcium, phosphorus, magnesium, zinc, iron and copper was studied in balance trials in mature ponies in a three by three latin square experiment. A basal diet consisting of one third each of oats, beet pulp and a commercial pelleted, complete horse ration and containing 336 ppm aluminum was supplemented with AlC1(3) . 6H2O. The middle and high level aluminum diets contained 1370 and 4500 ppm aluminum respectively. There was little difference in effect between the middle level aluminum and basal diets. The ponies were in negative phosphorus balance when fed the high level aluminum diet because phosphorus absorption was suppressed. Calcium absorption was unaffected by aluminum intake but the ponies were in negative calcium balance when fed the high aluminum diet due to the greater urinary excretion of calcium by the ponies. Presumably, calcium was excreted in urine because it was not utilized in the formation of bone crystal due to the lack of phosphate. Plasma calcium was elevated and plasma phosphorus was depressed when ponies were fed the high aluminum diet. Plasma hydroxyproline concentration was increased suggesting that bone turnover was increased due to aluminum effects on phosphorus and calcium metabolism. Magnesium, zinc, iron and copper metabolism were unaffected by aluminum intake.     

Hepatic iron accumulation over time in European starlings (Sturnus vulgaris) fed two levels of iron.

European starlings (Sturnus vulgaris) were used as a passerine bird model to examine the effect of dietary iron on the level of hepatic iron in birds. Nestling and fledgling starlings (n = 56) were raised on a controlled-iron diet. When birds maintained constant body weight, they were assigned in pairs to cages, and baseline sampling was performed. Pairs were then assigned to one of two diets: the controlled-iron diet (168 ppm, dry basis) or a high-iron diet (3,035 ppm, dry basis). Dry-matter intake and iron consumption were recorded. Dry-matter intake did not differ between the dietary treatment groups and was stable during treatment periods. Iron intake was higher in the high-iron group (P < 0.05). Birds were euthanized at baseline, 8 wk, and 16 wk. Body, liver, and spleen weights were measured. Hepatic iron and copper concentrations were determined. Body weight did not differ between the two treatment groups or among individuals for the study duration. Liver iron concentration differed over time and between treatment groups. Birds receiving both treatments had similar liver iron content at week 8 (3,107 +/- 228.6 ppm and 3,122 +/- 306.2 ppm high and controlled iron, respectively; P > 0.05), but by week 16, birds consuming the high-iron diet had greater hepatic iron levels than those consuming the controlled-iron diet (5,929 +/- 937.2 ppm and 3,683 +/- 229.5 ppm high and controlled iron, respectively; P < 0.05). Birds on the controlled-iron diet also had higher hepatic iron at 16 wk than at 8 wk. Liver copper decreased over time in all birds regardless of treatment. Results show that both dietary iron level and duration of time influenced hepatic iron storage. The controlled-iron diets still allowed accumulation of hepatic iron in an 8-wk period.     

Some effects of changing protein levels during the pullet laying year

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.     

The effects of early and late maturity on the protein requirements of pullets

Growing pullets were exposed to two light patterns which caused a difference in sexual maturity of 5 weeks. From 28 to 38 weeks of age they were fed diets containing crude protein levels of 7.0, 8.5, 10.0, 11.5, 13.0 and 14.5 per cent. Yellow maize provided 45 per cent and soyabean meal 55 per cent of the protein in all six diets.

Rate of lay, egg weight and body weight were greater in the late maturing flock than in the early flock at the start of the assay and throughout the assay period. The late maturing pullets required more protein to reach and maintain their maximum potential than the early birds, presumably because their potential output was greater. The late birds showed a diminishing but continued response to protein up to the highest level fed (14.5 per cent corresponding to 23 g. protein per bird day). The early maturing pullets showed no response to dietary protein levels beyond 11.5 per cent and their estimated protein requirement was about 16 g. per bird day.

When limiting amounts of protein were fed (7.0–10.0 per cent of the diet) the two flocks achieved similar levels of egg output. In both flocks and throughout the assay, body weight and egg weight fell at the two lowest levels and increased at the three highest levels of protein.

It is concluded that the protein requirements of early maturing and late maturing flocks of pullets may differ, but only in a way which corresponds directly with their different potential outputs. In the late flock, which had the higher protein requirement, excellent production was obtained with a diet containing 14½ per cent crude protein all of which came from vegetable sources.     

The influence of manganese in association with other dietary components on certain shell characteristics

Four groups of pullets were given, from 17 weeks of age, a high‐Mn diet, or one of three low‐Mn diets. Hens given low‐Mn diets laid eggs with poor shells, judged by appearance, strength and thickness at the start of lay, but only one low‐Mn diet (diet 4), was associated with poor shells throughout 12 months of egg production. Supplementary Mn (100 mg/kg) added to low‐Mn diets after 12 months had no significant effect during the next 2 months on shell appearance score, strength or thickness.

In a second experiment, four groups of pullets aged 16 weeks were given diets of low or high Mn content and high or moderate P content. At the start of the laying period there was a significant interaction between Mn and P, a high level of P increasing shell defects caused by low Mn. At a later stage, 4 months after the start of egg laying, high P significantly reduced shell strength and thickness but had no effect on appearance score: low Mn had only a small non‐significant effect on any shell characteristic at this stage.

In a third experiment pullets of five White Leghorn type hybrids aged 16 weeks were given diets of low or high Mn and high or low Ca until the point of lay, when all birds received the high‐Ca diet but continued receiving the level of Mn given from 16 weeks of age. Only shells produced at the start of lay were studied. Type of hybrid influenced the number of soft shells produced but had no significant effect on other characteristics. Manganese significantly influenced all shell measurements and a high level of Ca increased the number of soft shells, decreased strength and thickness but had no effect on appearance score. There were no significant interactions.     

Effect of low protein diets for growing Leghorn pullets upon subsequent laying performance

An experiment was conducted with White Leghorn pullets to study the effect on laying performance of dietary protein content and amino acid supplementation during the growing period. From 0 to 6 weeks of age birds fed on diets containing either 149 g protein/kg supplemented with methionine and lysine or 182 g protein/kg grew faster than those fed on a diet containing 149 g protein/kg alone. However, only those fed on the supplemented diet utilised their food more efficiently. From 7 to 20 weeks of age neither body weight gain nor food utilisation was affected by the dietary protein content. Pullets fed the low protein diet supplemented with 2 g methionine/kg and 2.5 g lysine/kg during the period of 0 to 6 weeks of age had significantly better egg production than birds fed the low protein diet alone. The dietary protein content during 7 to 20 weeks of age did not influence subsequent egg production.     

Selection for high and low percentages of chicken eggs with blood spots 1

Eggs were examined for presence of blood spots in a base generation of White Leghorns part of which were fed on an adequate diet and part on a diet inadequate in vitamin A that increased blood spot incidence. From theory and data, the selection differential was larger for low incidence selection for pullets on the inadequate diet than pullets on the adequate diet. Statistical and genetical models were given for estimating variances of this all‐or‐none trait with h ² = 0.16 and 0.60 for the lines on the adequate and inadequate diets respectively.

Predicted selection gains for individual selection of females alone were: adequate diet, low ‐0.91%, high 2.36%; inadequate diet, low ‐10.71%, high 14.58%. After eight generations of selection for high and low incidence on each of the diets there was a difference of 23.5% between high and low lines selected on the adequate diet and 37.7% on the inadequate diet. Evidence was inconclusive that selection for low incidence on the inadequate diet produced birds with a lower incidence on the adequate diet than birds selected on that diet.

Specific gravity showed a negative correlated selection response in both lines on the adequate diet but no correlated response was evident in the lines on the inadequate diet. There was a negative correlated response for Haugh units and a positive correlated response for blood spot size in all lines. Egg weight did not show a correlated selection response.     

The recovery of laying birds from a period of low protein feeding

Laying pullets which had been fed diets containing 7, 8½, 10, 11½, 13 and 14½ per cent crude protein for 10 weeks were returned to a normal diet containing 14½ per cent crude protein. For birds which had received the lowest protein diet, rate of lay improved from about 30 per cent to over 80 per cent in 4 weeks. Egg weight, body weight and food consumption also increased rapidly. In the period from 3 to 20 weeks after restoring a normal diet the pullets which had previously been fed 7 per cent and 8½ per cent crude protein showed a rate of lay and an average egg weight substantially better than that of control birds which had always received the 14½ per cent crude protein diet.

It is concluded that a period of low protein feeding does not impair the subsequent ability of the laying bird to reach normal levels of output. On the contrary, birds which are denied a normal protein intake for a time tend to compensate when returned to normal feeding by laying more eggs and bigger eggs. However, in this experiment, the compensation was not enough to offset the loss in yield incurred during low protein feeding.     

Dietary selection of protein and energy by pullets and broilers

1. White Leghorn pullets and sexed broilers were allowed a free choice of two “ split‐diets “ which were concentrated sources of either crude protein (463 g/kg diet) or energy (13.32 to 14.00 MJ/kg diet).

2. Pullets receiving these two diets displayed a slower, but more uniform growth rate than did birds offered a single conventional diet. Up to 11 weeks of age, control birds consumed significantly more protein while the converse was true from 11 to 20 weeks. These differences are discussed in relation to the stage of sexual maturity.

3. Broilers offered the split‐diets grew more slowly and had an inferior food conversion ratio compared with control birds fed on a two‐stage rearing programme.

4. Among the broilers offered split‐diets, the usual sex differences were not observed for weight gain or carcass fat content.     

两种锗化合物对肉鸡的促生长作用及其毒性

就使用两种不同锗化合物——二氧化锗(GeO_2)和四氯化锗(GeCl_4)对肉用仔鸡的促生长作用及其毒性进行了研究。每次试验使用144只不同处理组。喂饲基础日粮组为对照组。在各试验组中分别加入1,10,100,1000mg/kg 锗(GeO_2)和1,10,100,1000mg/kg 锗(GeCl_4)。加二氧化锗的试验组中,当加入锗10mg/kg 时,鸡增重提高12%(P<0.05),饲料转化率提高7.5%(P<0.05)。相反,四氯化锗不能促进鸡的生长,当锗为100mg/kg 时,鸡的各项生产性能指标均有所下降。当饲料中锗浓度为1000mg/kg,不论它来自二氧化锗还是四氯化锗均对鸡有很大毒性,所有鸡分别于17天和28天后死亡。在试验2中,将鸡分为8个不同处理组,喂以基础日粮(对照组)和2,5,10,20,50,100和200mg/kg。锗(二氧化锗)。当锗浓度为5mg/kg时。对鸡的生长有轻微促进作用,与对照组相比提高3.3%,各处理组均未发现中毒症状。根据试验结果可推断,锗对鸡的半致死量(LD_(50))略低于大鼠,约为500～600mg/kg 体重。每日每只鸡摄入18mg 锗,是安全的。     

The performance of laying hens fed on rearing and laying diets containing urea

In an experiment using 2880 light hybrid pullets the effect of urea on laying performance has been assessed. Birds received one of three low‐protein rearing diets from 7–20 weeks of age. The control rearing diet, containing 11.5% crude protein, was compared with two diets containing 13.2% crude protein, one in which the protein was from conventional sources and the other containing 11.5% conventional protein and urea equivalent to 1.7% crude protein. At 20 weeks birds were allocated to one of two laying diets formulated to meet essential amino acid requirements. Half the birds from each rearing treatment received a low‐protein diet (14.7%) and the remaining birds received a 16.4% protein diet which included urea equivalent to 1.7% crude protein. Laying performance was recorded for the next 30 weeks.

Body weights of birds fed on the urea‐containing rearing diet were similar to those of birds fed on the control diet (1.22 kg) and less than those on the 13.2% protein diet (1.29 kg). Urea in the laying diet caused a 2% increase in egg production and tended to cause an improved food conversion efficiency. In contrast, a 3.5% less efficient food conversion was found during laying in birds which had received urea during rearing, compared with birds which had received the low‐protein rearing diet. Birds receiving the 13.2% protein diet, containing no urea, during rearing laid smaller eggs than birds fed on the 11.2% protein rearing diet. A high mortality rate occurred during laying due to lymphoid leucosis but no differences between treatments were found.     

The effect of low‐protein grower diets on the subsequent response of pullets to quantitative food restriction during lay

1. The laying responses of pullets fed from 8 weeks of age on a 12.5% protein grower diet and subsequently subjected to food restriction commencing at various times between 20 and 40 weeks of age were compared with those of pullets reared on diets containing 12.5 or 16% protein and given access to food throughout lay.

2. Restricted feeding during lay of pullets reared on the low‐protein diet substantially improved laying performance, the best results being obtained from pullets fed the low‐protein grower diet and restricted from 20 weeks. The laying responses of pullets restricted after peak‐lay at 40 weeks of age were not significantly different from those of birds restricted prior to peak‐lay.

3. Maximal egg production of 81 % over the 48weeks of the experiment was attained on an average daily ME intake of 270 kcal (1130 kJ) and a FCR of 2.06 : 1.

4. It is suggested that food restriction of laying pullets previously reared on low‐protein diets may be successfully utilised prior to peak‐lay provided such restriction is not so severe as to retard the rate of attainment of mature weight and a continued slight gain in weight thereafter.