Use of Lathyrus Sativus L. (var. seminis albi) as a foodstuff for poultry

1. The gross composition of Lathyrus sativus was examined, and its use as a foodstuff for growing chicks over time as well as the influence of supplementation with certain amino acid combinations were studied.

2. Chemical analyses indicated lathyrus to be high in crude protein with adequate concentrations of most inorganic elements and amino acids except methionine and cystine.

3. The performance of growing chicks fed 800 g/kg lathyrus over a four week period was significantly poorer than those given a wheat/ soyabean meal‐based diet (P<0.05), but there appeared to be some adaptation to the antinutritive factors in the lathyrus.

4. Chick performance was markedly improved by dietary methionine supplementation alone (P<0.05); it was slightly better when trypto‐phan was added in combination with methionine but was still inferior to that on a wheat/soyabean meal‐based diet.

5. Supplementation of lathyrus‐based diets with methionine and tryto‐phan may improve chick performance, but it is not sufficient to overcome the effects of antinutritive factors in the legume.     

Egg discolouration effects of including screw‐press cottonseed meal in laying hen diets and their prevention

The egg discolouration effects of including a screw‐press cottonseed meal (CSM), containing 68.2 g residual lipid/kg, 290 mg cyclopropenoid fatty acids (CPFA)/kg and 1226 mg free gossypol/kg, in laying hen diets at 300 g/kg were examined.

2. Discolouration prevention methods included treating the meal with ferrous sulphate heptahydrate (FSH), in solution or as crystals, at a 4:1 weight ratio of iron to free gossypol (experiment 1), and reducing its residual lipid (CSL) content to 4.2 g/kg by hexane extraction (experiment 2).

3. In freshly laid eggs, no discolouration was observed when hens were fed a CSM‐based diet containing 250 mg free gossypol/kg and 87 mg CPFA/kg in experiment 1, but slightly brown yolks were produced in experiment 2.

4. Storage of the eggs at 22°C led to yolk mottling, an effect believed to be the initial stages of the brown yolk discolouration.

5. Storage of the eggs at 5°C resulted in enhancement of the brown yolk discolouration, apricot discolouration on surfaces of most yolks and pink albumen discolouration. These effects were prevented when the CSM was extracted with hexane. Apricot yolk and pink albumen discolourations were also produced when hens were fed a non‐CSM diet containing crude CSL at 20.5 g/kg.

6. Dietary CSL increased egg fat saturation, altering the ratios of stearic to oleic, palmitic to palmitoleic and heptadecanoic to hepta‐decenoic fatty acids.

7. Treatment of CSM with FSH reduced the slight brown yolk discolouration in fresh eggs (experiment 2) and the yolk mottling in warm‐stored eggs. Both in solution and as crystals, FSH prevented the enhancement of brown yolk discolouration in cold‐stored eggs, leaving most eggs with apricot yolk and pink albumen discolourations.

8. Treatment of CSM and CSL with FSH reduced the CPFA‐related effects on yolk fat saturation, and the colour and pH changes in cold‐stored eggs.

9. Exposure of yolks to ammonia vapour provided a useful test to predict the development of the gossypol‐related brown discolouration in stored eggs.     

Replacement of groundnut cake by dried poultry manure in the diets of laying hens

1. The effect on food consumption by pullets when dried poultry manure (DPM) replaced part of dietary groundnut cake depended on the strain of the birds: in two of the three hybrids food consumption was not affected when up to 100 g DPM/kg was fed.

2. Increases in food consumption were accompanied by increases in egg production.

3. The food required per dozen eggs was improved by up to 100 g dietary DPM/kg and variation in the sizes of eggs laid depended on the hybrid.

4. Concentrations of DPM up to 100 g/kg did not affect the water‐soluble nitrogen content of the egg but the crude albumen nitrogen content was depressed at concentrations of 80 g/kg or above.

5. Feeding DPM to laying pullets depressed body weight.     

Comparison of wheats of high or conventional protein content with added lysine in diets for layers

1. High‐protein wheats (196 or 210 g/kg) were compared with conventional wheat (163 or 162 g/kg) in layers’ diets in three experiments.

2. In diets of 160 g protein/kg without added lysine, high‐protein wheats caused lower rates of production and egg size than conventional wheats in White Leghorns. Lysine supplementation of the former diets eliminated these differences.

3. The improvements in egg production and egg weight were significant with 1 g additional lysine/kg and egg production tended to improve further with 2 g additional lysine/kg, as did egg weight with all subsequent additions, but not significantly so.

4. With diets containing high‐protein wheats supplemented with lysine, high egg production and egg weight could be obtained without a protein supplement (e.g. soyabean meal).

5. In broiler‐breeders egg production was lower and food conversion poorer with high‐protein wheat despite added lysine.     

Lysine requirement of broiler chicks as affected by protein source and method of statistical evaluation 1

1. An experiment was designed to test if the lysine requirement, expressed as g lysine/kg CP, was the same for several protein sources.

2. Groundnut meal, groundnut meal adjusted with indispensable amino acids or sesame meal supplied the dietary CP at 180 g/kg diet. Increments of lysine (1.5 g/kg diet) were added to each of these diets.

3. The gain, food intake and food efficiency responses of broiler chicks were analysed using a quadratic equation and a two‐slope method. An estimate of lysine requirements was also obtained from a survey of college students.

4. The different methods produced widely different estimates of lysine requirement.

5. The average lysine requirement was estimated at 50.1 g lysine/kg CP for groundnut meal, 61.7 for adjusted groundnut meal and 54.9 for sesame meal.

6. Reasons for the effect of statistical analysis and protein source on lysine requirement are discussed.     

Hydrolysed feather protein as a source of amino acids for broilers

1. The inclusion of 25 g hydrolysed feather meal (HFM) in each kilogram of diet (floor experiment) and 60 g/kg (cage experiment) did not depress performance.

2. Chemical tests indicated 72.5% of the total lysine in HFM was available.

3. Total lysine concentration of 11.3 g/kg diet maximised performance during the period 0 to 34 d.

4. Reduction in dietary methionine content during the period 0 to 34 d from 4.2 g/kg to 3.2 g/kg did not depress performance on diets containing 60 g HFM/kg.

5. The results indicate that at least 57% by weight of the total sulphur amino acid requirement of broilers can be provided by cystine.     

The effect of delaying the onset of laying in pullets with a low‐calcium diet on subsequent egg production

1. A low‐calcium diet (0.5 g calcium/kg) was used to prevent the onset of laying in young pullets.

2. It was fed at 16 weeks of age to five separate groups (groups 2 to 6) each of 50 to 60 birds.

3. Group 2 was fed on a normal layers’ diet at 23 weeks of age, group 3 at 27 weeks, group 4 at 31 weeks, group 5 at 35 weeks and group 6 at 55 weeks while the control group (group 1) of similar size to groups 2 to 6 was subjected to a normal commercial treatment for laying stock.

4. In all the experimental groups the onset of sexual maturity occurred normally, but only one or two eggs were laid before laying ceased under the influence of the treatment.

5. Laying re‐started when the hens were fed on a normal diet and production rapidly rose to a high level.

6. Groups 1, 2 and 3 differed little in the total number of eggs produced up to 72 weeks of age.

7. In all experimental groups there were fewer very small, small and medium eggs than in the control group.

8. It is suggested that the use of a low‐calcium diet before the onset of lay may have advantages which could be exploited on a commercial scale.     

Supplemental dietary L‐tryptophan effects on growth,meat quality,and brain catecholamine and indoleamine concentrations in Turkeys

1. An experiment was conducted to investigate the effects of feeding supplemental tryptophan during the two weeks before market on growth, mortality during transportation, meal quality and brain neurotransmitter concentrations in male turkeys.

2. Brain serotonin, 5‐hydroxyindoleacetic acid and norepinephrine concentrations were increased dose‐dependently with 1.0, 2.0 and 3.0 g/kg supplemental dietary tryptophan.

3. Supplemental dietary tryptophan had no effect on body weight gain, food intake, food efficiency or mortality.

4. Carcase and individual thigh weights were significantly heavier in those birds fed l.0 g/kg supplemental tryptophan.     

Available amino acid content and microbiological condition of dried poultry manure

1. Excreta from laying hens, collected at daily or weekly intervals, was dried in a commercial oil‐fired drier. Samples were analysed at monthly intervals over an 18‐month period.

2. Leaving the excreta for 1 week resulted in a decrease in nitrogen content from 59.5 g/kg to 54.1 g/kg (P< 0.05) and in the moisture content from 108.5 g/kg to 83.3 g/kg (P<0.05).

3. The mean values of available methionine, tryptophan and leucine were little affected by storage and were 0.340, 0.555 and 1.041 g/16 g N, respectively.

4. Salmonellae were not detected in any sample, coliform bacteria were detected in nine (26%) and anaerobic spore formers in 26 samples (76%).     

Effects of nutrient concentration and dietary presentation on performance of dwarf hens

1. Diets containing 170 or 190 g protein/kg and 10.9 or 11.7 MJ ME/kg in all combinations were offered to dwarf hens in two dietary presentations: a complete mash or a form in which part of the protein and calcium contents were presented as soyabean meal pellets and limestone grit respectively.

2. Egg production and egg mass output were higher with the 190 g protein/kg diets.

3. Lower‐energy diets gave better egg production, while higher‐energy diets containing 190 g protein/kg improved food conversion efficiency.

4. Separation of protein and calcium constituents tended to give better egg production, food conversion efficiency, shell thickness and egg mass output.     

Effect of dietary inclusion of ascorbic acid and palm oil on the performance of laying hens in a hot tropical environment

1. Two experiments were conducted to evaluate the effects of including ascorbic acid (AA), palm oil or a combination of both in the diets of laying hens during the hot months in a tropical environment.

2. The inclusion of AA improved egg production, food intake and efficiency of utilisation, and decreased the cost of food per kg egg. The addition of 400 mg AA/kg diet gave the most efficient performance.

3. Palm oil inclusion reduced the effect of heat stress and increased egg production, egg weight, food intake and efficiency of utilisation.

4. When 200 mg AA and 50 g palm oil/kg were used, additive responses were obtained with further improvements in egg production, food cost and efficiency.

5. Ascorbic acid and palm oil when fed alone or in combination reduced the incidence of cracked eggs.

6. Thus, 400 mg ascorbic acid/kg of diet, 50 g palm oil or 200 mg AA plus 50 g palm oil/kg diet ameliorated the effects of heat stress in laying hens.     

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

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

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

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

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

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

Behaviour of egg shell under compression in relation to deformation measurements1

1. The egg does not completely obey Hook's law when compressed between flat surfaces.

2. Deformation was not completely reversible due to crumbling at the points of contact with the force.

3. There are three components of non‐destructive deformation: (a) local deformation at the points of contact, (b) local surface crumbling and (c) deformation of the over‐all shell structure.

4. The latter two are uncontrolled, contributing to errors in the prediction of fracture force and depending on the non‐destructive force applied.

5. These effects should be considered in test selection and interpretation.

6. The optimum non‐destructive force was found to be 1 kg.     

Effects of ascorbic acid and 1, 25‐dihydroxycholecalciferol on alkaline phosphatase and tibial dyschondroplasia in broiler chickens

1. The effects of graded amounts of dietary ascorbic acid with or without 10 μg/kg dietary 1,25‐dihydroxycholecalciferol on performance, blood and bone variables were measured in broiler chicks.

2. 1,25‐Dihydroxycholecalciferol prevented the tibial dyschondroplasia and rickets caused by feeding a low calcium diet. Gain:food was decreased, but body weight was not affected by feeding 10 μg/kg 1,25‐dihydroxycholecalciferol. Phytate phosphorus retention was increased by dietary 1,25‐dihydroxycholecalciferol.

3. Dietary ascorbic acid did not influence the incidence of tibial dyschondroplasia, but did reduce the incidence of rickets at a dietary concentration of 250 mg/kg. Gakv.food was increased when 250 or 500 mg ascorbic acid/kg diet were added along with 10 μg/kg 1,25‐dihydroxycholecalciferol in one of two experiments.

4. Alkaline phosphatase activity and plasma 1,25‐dihydroxycholecalciferol were not affected by the dietary treatments. Plasma 25‐hydroxycholecalcif‐erol concentration was decreased by dietary 1,25‐dihydroxycholecalciferol.

5. Ascorbic acid had no synergistic effects with 1,25‐dihydroxycholecalciferol on the blood and bone variables investigated in broiler chickens at the dietary concentrations of 1,25‐dihydroxycholecalciferol used in this work.     

Interaction between dietary 1,25‐dihydroxycholecalciferol and calcium and effects of management on the occurrence of tibial dyschondroplasia,leg abnormalities and performance in broiler chickens

1. Two experiments were performed to compare the relative effectiveness of feeding 1,25‐dihydroxycholecalciferol (1,25‐DHCG) in minimising leg abnormalities in broilers with other methods and to investigate interactions between dietary 1,25‐DHCC and calcium.

2. Adding 5 μg 1,25‐DHCC/kg to a diet containing 12 g calcium/kg was more effective than early food restriction or meal feeding in preventing leg abnormalities but was found to cause a growth depression.

3. The second experiment, which had a factorial design, with diets containing 7.5, 100 and 12.5 g calcium and 0, 2.0, 3.5 and 5.0 μg 1,25‐DHCC/kg, showed linear and quadratic interactions between these dietary factors. Diets with higher concentrations of both 1,25‐DHCC and calcium resulted in growth depression associated with hypercalcaemia.

4. The incidence of tibial dyschondroplasia (TD) at 3 weeks of age was highest with the basal diet containing 7.5 g calcium/kg and was markedly reduced by addition of 1,25‐DHCC and/or calcium. The incidence was very low or non‐existent when 1,25‐DHCC was fed at 3–5 μg/kg or greater.

5. Feeding 5 μg/kg 1,25‐DHCC had no effect on plasma 1,25‐DHCC concentrations, although at the higher dietary calcium contents plasma concentrations of 25‐hydroxy‐ and 24,25‐dihydroxy‐cholecalciferol were lower in those birds fed 1,25‐DHCC.

6. It is concluded that 1,25‐DHCC is most effective in preventing TD without accompanying growth depression when it is fed in conjunction with diets containing less than 10 g calcium/kg.     

Voluntary food restriction by laying hens mediated through dietary self‐selection

1. Individually caged Single Comb White Leghorn hens simultaneously received two diets which allowed selection of certain nutrients: these “ split‐diets “, essentially provided concentrated sources of either protein and energy (191 g crude protein, 12.82 MJ ME and 4.7 g Ca/kg diet), or calcium (107 g CP, 7.28 MJ ME and 131 g Ca/kg).

2. During four, 28‐d periods of lay, birds offered these split‐diets consumed some 7% less food in total than did control birds receiving a conventional diet ad libitum.

3. Calculation of nutrient intakes showed that birds on the split‐diets consumed significantly less protein, energy and calcium than the control birds.

4. Giving split‐diets also resulted in superior shell quality; treatment differences were also noted in the timing of oviposition.

5. It is suggested that the voluntary reduction in food intake noted for birds offered split‐diets is associated with an appetite for calcium.     

Selection for food conversion in broilers: Body composition of birds selected for increased body‐weight gain,food consumption and food conversion ratio

1. Body composition was determined in 9‐week‐old chickens sampled from four lines selected either for increased body‐weight gain (line W), for increased food consumption (line F), for decreased food conversion ratio (line E), or at random (line C), after three, four and five generations of selection.

2. After five generations of selection the proportions of carcass water (678 g/kg) and protein (187 g/kg) were highest in line E and lowest (636, 180 g/kg respectively) in line F. The proportion of fat was lowest (83 g/kg) in line E and highest (134 g/kg) in line F.

3. Lines W and C were similar and intermediate to lines E and F for all the carcass constituents.

4. There was more fat in females (115 vs 98 g/kg) and less protein (177 vs 190 g/kg) and water (652 vs 665 g/kg) than in males.

5. Line differences in carcass composition were not appreciably altered if birds were killed at equal weight rather than equal age.     

The effects of dietary calcium concentration on pheasant breeder performance

1. Thirteen pens of breeding pheasants (Phasianus colchicus) were fed ad libitum on diets containing 20, 23 or 27 g calcium/kg.

2. All diets were formulated to contain 10.6 MJ ME/kg.

3. Three pens of birds receiving the diet containing 23 g calcium/kg were also offered grit free choice containing 280 g calcium/kg.

4. There were no effects of treatment on food consumption or reproductive performance.     

Utilisation of dried poultry manure by growing chickens fed on a practical diet

1. Dried poultry manure (DPM) has been tested as a replacement for groundnut cake in poultry diets.

2. Body weight gain, and the efficiency of food conversion were improved when the diet contained 50 g DPM/kg but higher rates of inclusion (100 or 150 g/kg) depressed growth.

3. Birds fed on diets containing 50 g DPM/kg yielded meat of comparable quality to those fed on the control diet whereas those fed on diets containing more DPM yielded meat containing more fat and less water.

4. The percentage moisture in the meat was inversely related to the lipid content.

5. Nitrogen retention was comparable in all groups.     

Effect of increasing cellulose in diets fed as crumbles or mash on the food intake and weight gains of broiler and Leghorn chicks

1. Two‐week‐old broiler and Leghorn cockerels were fed on diets containing 0, 100, 200, 300, 400, 500 or 600 g cellulose/kg in either crumble or mash form for 4 weeks.

2. Intake of the mash form of the cellulose‐diluted diets and associated body weights were less than those associated with the equivalent crumble diets which may have been due to decreased palatability of the former.

3. Broilers were unable to compensate for dietary dilution with cellulose by increasing food intake sufficiently to maintain nutrient intake with either mash or crumbled diets at any dilution.

4. At 100 g cellulose/kg for the mash diets and 100 and 200 g/kg for crumbled diets, Leghorns increased volume ingested by as much as 40% and maintained body‐weight gain and nutrient intake.

5. The results could be of value in designing feeding programmes for egg‐and meat‐type pullets.