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.     

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.     

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.     

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 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 diets containing raw and extrusion‐cooked rice bran on growth and efficiency of food utilization of broilers

1. Meat strain chicks were fed on diets containing 600 g rice bran/kg for the 7 to 8 week period required to reach broiler weight.

2. Extrusion cooking of rice bran resulted, in improved chick weight gain and food efficiency for the first two weeks of feeding, but this advantage was lost by the end of the feeding period.

3. Addition of 10 g calcium/kg to the stabilised rice bran diet prevented the decline in performance after two weeks of age, and birds fed on this diet continued to gain at an increasing rate until the end of the experiment.

4. Calcium supplementation of stabilised rice bran diets produced significantly greater gains and superior food utilisation compared to stabilised rice bran diets without added calcium.

5. Calcium supplementation did not affect weight gain of chicks fed on diets containing raw rice bran.

6. Taste panel evaluation of meat from birds fed on diets containing raw rice bran, stabilised rice bran, or no rice bran indicated a significant preference in only one combination tested. Any ‘off flavour could not be related to dietary treatment.     

Folic acid requirements of broilers

1. Dietary folic acid requirements of broilers were studied in three experiments using wheat‐ and maize‐based practical diets. Requirements were assessed on the basis of performance and metabolic criteria.

2. Growth and food conversion efficiencies were optimised with supplements of 1.5 mg folic acid/kg added to basal mash starter diets. The dietary folic acid requirement of broilers was estimated to be in the range of 1.7 to 2.0 mg/kg.

3. Red blood cell phosphoribosylpyrophosphate concentrations and dihydrofolate reductase activites did not show consistent changes over the range of dietary folate concentrations studied but plasma folate concentrations responded markedly to dietary folate supplementation.

4. Adding choline to diets in amounts greater than the normal requirement did not spare the requirement for folic acid.

5. It is suggested that minimum folic acid supplements for pelleted practical diets should be in the order of 2.5 to 3 mg/kg.     

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.     

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.     

Rapeseed meals in broiler diets: Effect on performance and sensory evaluation of carcasses

1. The effect of including rapeseed meal (RSM) in lieu of soyabean meal in broiler diets was determined.

2. Live‐weight gains, from 8 to 63 d, were depressed when the diet contained 150 g RSM/kg and there was a highly significant negative correlation between weight gain and inclusion rate of RSM over this period.

3. The efficiency of food utilisation was worse when the diet included 150 g solvent RSM/kg than when it contained no RSM: food efficiency was consistently poorer whenever RSM was included in the diet but the difference was significant only when the diet contained 10 g tallow/kg.

4. Carcasses from birds fed on diets containing 10 g tallow/kg had a better appearance than those from birds on diets containing 30 g tallow/kg, while the flavour of meat from birds fed on a diet containing 150 g solvent RSM/kg treatment was adversely affected. However, up to 100 g solvent RSM/kg may be included in broiler diets without affecting appearance, taste, texture or acceptability of the meat.

5. Inclusion of 50 g or more, solvent RSM/kg reduced growth rate and worsened food efficiency.     

Effect of a soluble polysaccharide (carboxy methyl cellulose) on the physico‐chemical conditions in the gastrointestinal tract of broilers

1. The effects of an indigestible soluble polysaccharide (carboxy methyl cellulose: CMC) on broiler performance (body weight gain, food and water intake) and on chyme characteristics (moisture content, viscosity, pH, osmolality and retention time) in broilers were studied.

2. In semi‐synthetic diets 0, 5.0 and 10.0 g/kg of cellulose was replaced by CMC on weight basis. These diets were fed to male broilers from 3 to 5 weeks of age.

3. When 10.0 g/kg CMC was included in the diet, food intake and body weight gain were reduced, compared to the 0, and 5.0 g/kg CMC diets. Food:gain ratio and water intake were increased at each CMC concentration. The significant quadratic response showed an increased response per 5.0 g/kg dietary CMC at the higher CMC concentration.

4. The viscosity in the supernatant of the chyme was linearly increased in all intestinal segments by CMC. A quadratic increase was observed in the crop. In the lower ileum, differences between the 5.0 and 10.0 g/kg CMC diets were not significant.

5. CMC increased the mean retention time of chromium in the duodenum and in the upper jejunum, and reduced the maximal rate of marker excretion. The transit time (first appearance of the marker in the excreta), however, was significantly reduced at the highest CMC concentration.

6. The osmolality of the intestinal fluid decreased less as the chyme moved from the duodenum into the lower ileum, with increasing concentrations of CMC.

7. The ileal pH was reduced linearly by the CMC content of the diet.

8. Based on a higher moisture content of the chyme in the CMC‐fed birds, and the higher jejunal and ileal osmolarities in those birds, it was concluded that the efficiency of both digestion and absorption was reduced by CMC inclusion in broiler diets.     

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.     

The performance of male ducklings given starter diets with different concentrations of energy and protein

1. Male ducklings were fed for 14, 21 or 28 d on diets containing 180, 200, 220 or 240 g of protein and 10.88 or 12.55 MJ of metabolisable energy (ME) per kg, followed by a common finisher diet until 56 d of age.

2. Birds given starter diets with 220 or 240 g of protein per kg were significantly heavier at 14 d than those given diets with 180 or 200 g protein per kg.

3. There was no significant benefit in feeding diets with protein levels greater than 180 g/kg for more than 14 d.

4. Diets with only 10.88 MJ of ME per kg produced significantly lighter birds at 28 and 56 d of age and significantly reduced food conversion efficiency up to 14 d.     

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.     

Evaluation of putative appetite suppressants in the domestic fowl (Gallus domesticus)

1. The effectiveness of the appetite suppressants fenflur‐amine, furanone and crotonolactone were evaluated in a series of experiments with adult male layers and growing broilers of both sexes fed on diets with concentrations of up to 1000 mg/kg.

2. Fenfluramine produced a curvilinear decrease in food intake and body weight in adult layers and growing broilers.

3. Inconsistent responses to furanone and crotonolactone were obtained with adult layers and broilers in cages, but a similar decrease in food intake and body weight for both drugs was recorded in male broilers raised in floor pens.

4. The responses to subcutaneous injection of 20 mg/kg of each drug on food intake over 24 h were comparable to those for dietary inclusion. Fenfluramine, however, produced a greater response in male compared with female broilers and induced signs of hyper‐thermia in broilers and layers.

5. Subcutaneous injection of 50 mg crotonolactone/kg was associated with decreases in the food intakes of 4 strains and there was evidence of different responses between lines.

6. It was concluded that none of the drugs used were likely to be suitable for the control of food intake in broiler breeder flocks.     

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.     

Replacement of maize by triticale in broiler diets

1. The nitrogen‐corrected metabolisable energy contents of the triticale varieties Multi Graze, Graze Grain 70, 204 and 131 were 12.28, 12.69, 12.37 and 12.03 MJ/kg respectively.

2. Increasing proportions (0, 25, 50 or 75%) of the maize of a diet were replaced by triticale 131 to provide diets of equal energy and nitrogen contents for broilers. These diets resulted in weight gains of 1.775, 1.782, 1.713 and 1.808 kg respectively at 8 weeks and there were no significant differences among efficiencies of food conversions.

3. Dressed carcass weights as percentages of body weight were 74.38, 75.01, 73.98 and 74.50 respectively and did not differ significantly.

4. Triticale in the diet did not seem to influence the relative weights of either liver or gizzard.

5. The flavour of the meat seemed to become less acceptable as the triticale in the diet increased but there were no significant differences in tenderness and juiciness of the meat caused by the treatments.     

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.     

Fat deposition and heat production as responses to surplus dietary energy in fowls given a wide range of metabolisable energy: Protein ratios

1. Female broiler fowl between 21 and 42 d of age were given diets with apparent metabolisable energy (AME) contents ranging from 8 to 15 MJ/kg at each of two crude protein (nitrogen x 6.25; CP) contents (130 and 210 g/kg).

2. Food intake was measured daily for 21 d. Body composition was determined at 42 d and gains in body mass, protein, fat and gross energy calculated by comparison with a group analysed at 21 d. Heat production was calculated by difference between AME intake and energy gain.

3. Decrease of food mass intake with increased dietary AME concentration limited the increase in AME intake to about 25%, despite the near 2‐fold range of AME concentrations.

4. There was no effect of CP concentration on food mass intake. CP intake was directly related to CP: AME ratio.

5. When body weight differences were taken into account, heat production was independent of dietary AME concentration, but increased by about 8% on the higher‐protein diets.

6. There were strong linear correlations between dietary CP:AME ratio and carcase protein: energy ratio, carcase fat content and carcase protein content.

7. It was concluded that the growing fowl responded to dietary nutrient: energy ratio, and the associated differences in nutrient and energy intakes, by varying the rate of energy deposition as fat, without regulatory variation of energy dissipation as heat.     

Performance of laying hens fed on low sulphur amino acids diets supplemented with choline and methionine

1. Two experiments were carried out to examine the possibility of replacing a part of the methionine content with choline in a layers’ diet.

2. In the first a low methionine diet with 2.6 g methionine/kg was supplemented with 0.3, 0.6, 0.9 and 1.2 g DL‐methionine/kg. Choline at 1.12 g/kg was added to the diets, which contained 5.4, 6.0 and 6.6 g TSAA.

3. In the second diets with 3.02, 3.80, 4.53, 5.30, 6.04 and 6.51 g TSAA/kg were used and 0.94 g choline/kg was added to these diets.

4. Supplemental methionine increased egg production but not egg weight in the first experiment. When the low TSAA diet was supplemented with choline, egg output increased slightly but not significantly.

5. When supplemental methionine was added to the low protein and TSAA diets in experiment 2 it increased egg production and egg weight. Added choline did not increase egg production or egg weight, even with the diet very low in protein and TSAA. Body weight gain, food intake and feed conversion efficiency of food utilisation were improved by supplemental methionine but not choline.