Rapid determination of metabolisable energy of foods using cockerels

1. Adult cockerels were trained to consume their daily food allowance of about 100 g in 1 h. Excreta were collected for the next 24 h and the metabolisable energy (ME) content of the diet was determined.

2. Two different diets were used to study effects of ME on adaptation to diet. Repeatable estimates of ME were obtained without a period of adaptation.

3. No difference in ME was found when a test diet was fed to adult cockerels for 1 h, or fed continuously and excreta collected over 5 d. The conventional total collection method of determining ME using groups of growing chickens yielded similar results.

4. Excreta collected between 24 and 48, or 48 and 72 h post‐feeding yielded constant energy values following feeding of two different diets, indicating that all excreta from the 1‐h feeding were voided during the next 24 h.

5. The method is precise and results can be reported 36 h after receipt of food sample.     

A comparison of the energy and nitrogen metabolism of fed ducklings and chickens

1. Energy measurements were made over 4 d on groups of three ducklings (aged from 5 to 22 d), and three broiler chickens (aged from 11 to 32 d) offered high‐ or low‐energy diets.

2. Food, metabolisable energy (ME) and water intakes were significantly higher for ducklings than for chickens. The ratio of water : food was 4.2 : 1 and 2.3 : 1 for ducklings and chickens, respectively. The food conversion ratio differed between diets but not species. Performance was generally better for both species on the high‐energy diet.

3. Heat production, energy, fat and protein retentions were higher for ducklings than chickens, and ducklings retained 0.44 of their energy as fat compared with 0.37 for chickens. Overall the ratio of protein (g) to fat (g) retention was 2.2 : 1 and 2.8 : 1 for ducklings and chickens respectively.

4. For ducklings, metabolisability of the high‐energy diet declined from 0.774 to 0.747, and to a lesser extent of the low‐energy diet, as they aged. There was no such decline for chickens. Net efficiency of utilisation of ME for gain was 0.64 for ducklings compared with 0.50 for chickens.

5. Fractional retention of dietary nitrogen (N) was 0.62 for ducklings and 0.55 for chickens. Gaseous ammonia‐N was 4.5 and 2.2%, respectively, of N retained.

6. In a second experiment groups of ducklings only, were offered high‐and low‐protein diets from 12 to 22 d of age. Comparisons among four diets showed that food and energy intake was lower on the low‐protein diet than on the other three. Energy retention on the high‐energy diet was greater (P<0.05) than on the other three diets.

7. It was concluded that a high‐energy diet is important for ducklings and chickens for maximum biological performance during the first 4 weeks of life.     

Effects of environmental temperature,dietary energy,sex and age on nitrogen and energy retention in the edible carcase of broilers

1. Two environmentally‐controlled houses, one set at constant 21°C (low temperature, LT) and the other set at diurnally cycling 21°C to 30°C (high temperature, HT), and two dietary energy concentrations of 13 MJ ME/kg (low energy, LE) and 13.8 MJ ME/kg (high energy, HE) were used to study nitrogen and energy retention in the edible carcase of male and female broilers slaughtered at 34 and 54 days.

2. Carcase nitrogen was higher in males than in females, and in birds reared at LT than in those reared at HT.

3. Birds at LT and on HE diet, regardless of sex, retained more energy as fat in their carcases than those at HT and on LE diet respectively.

4. Maintenance energy requirement averaged 6.70, 7.67, 7.43 and 9.01 kJ per g metabolic body size (kJ/gW 0.66) for broilers at HT and LT up to 34 d and at HT and LT up to 54 d, respectively.

5. There was a similar increase with age in the energy requirement for growth but with requirements of broilers at LT consistently lower than for those at HT.     

Protein and energy metabolism in two lines of chickens selected for growth on high or low protein diets

1. Genetic adaptation was investigated in broilers selected for seven generations on a normal (A) or a low (B) protein diet.

2. Protein and energy metabolism were studied in males from these selected lines fed on a diet of intermediate protein content.

3. All selected birds retained more nitrogen than those studied 10 years previously.

4. There was no difference in nitrogen retention between groups, although relative growth rate of group B birds was higher.

5. Heat productions relative to gross energy intake were 0.38 (group B) and 045 (group A). Energy retentions relative to gross energy intake were 0.39 (group B) and 0.35 (group A); the difference being primarily due to higher fat retention in group B.

6. Using a common maintenance requirement for metabolisable energy, group B utilised metabolisable energy for growth (0.78) better than did group A (0.71).

7. At 53 d of age plasma glucose (10%) and insulin (50%) were higher in group B than in group A.     

Mango seed kernels as an energy source for chicks1

1. Chemical analysis of a sample of ground mango seed kernels (MSK) revealed the following percentage composition: dry matter, 91.55; ash, 1.97; protein, 6.74; ether extract, 12.53; fibre, 1.30; nitrogen‐free extract, 77.46.

2. The ME content of MSK was 1.82 kcal/g.

3. The percentage retention of the crude fat content of MSK was only 3.38%.

4. Substituting MSK for corn at 10 or 20% led to reduced growth rate and poorer food consumption and a reduced efficiency of food utilisation in the period 0 to 4 weeks.     

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.     

The effect of sodium sulphate and methionine on the utilisation of non‐protein nitrogen by laying hens

1. The response of layers to adding diammonium citrate (DAC), sodium sulphate or methionine to a basal diet containing 136–3 g protein/kg was determined.

2. Supplementing the diet with DAC equivalent to 25 g protein/kg did not improve egg production, the efficiency of food utilisation, egg weight, nitrogen retention or the apparent absorption of lysine and methionine; increases in food intake and in the concentration of methionine in the serum and liver were observed.

3. Adding sodium sulphate, alone or with DAC, did not affect the variables noted above.

4. Supplementation of the basal diet with methionine increased egg production, egg weight, food intake and the concentrations of lysine in the serum and liver.

5. It is concluded that the supplemental NPN was used only in serum protein synthesis.     

Studies on the incorporation of triticale in diets for growing chicks

1. The classical ME value of triticale varied from 12.305 to 13.778 kJ/g or 11.819 to 13.016 kJ/g corrected for N‐retention depending upon method of calculation.

2. Substituting triticale for maize, weight for weight, but not on a iso‐nitrogenous basis, in a groundnut oil cake (GNC) starter diet improved weight gain (P < 0.05) when the substitution exceeded 75% without affecting the protein efficiency ratio (PER).

3. A similar substitution in a soybean oil meal diet, improved weight gain (P < 0.05) at 50% or more but PER declined (P < 0.05).

4. The net protein utilisation and protein retention efficiency values of the diets in which maize protein was replaced by triticale protein were significantly reduced.

5. The maize‐GNC diet was equally limiting in methionine and lysine while the triticale‐GNC diet was not.

6. The growth and food efficiency obtained with a triticale‐GNC diet was higher (P < 0.01) than with the maize‐GNC diet but not with a maize‐GNC supplemented with fish meal and methionine.

7. It is concluded that triticale could quantitatively substitute maize in the starter diets.     

Incorporation of triticale in layer diets

1. Diets containing either maize or triticale were fed unsupplemented or supplemented with meat meal or groundnut oil to White Leghorn pullets for two periods of 11 weeks each.

2. The egg production of birds fed on the unsupplemented triticale diet was significantly higher than that of the birds fed on the unsupplemented maize diet, but was not significantly different from that of the birds fed on the maize plus meat meal diet.

3. Protein quality of the unsupplemented triticale diet as judged by efficiency of nitrogen retention was similar or inferior to that of the unsupplemented maize diet.

4. The higher protein content of triticale and the increased intake of these diets seemed to be responsible for the better performance observed.

5. Addition of groundnut oil to the triticale diet did not improve either egg weight or production.

6. It is concluded that the quantitative substitution for triticale of maize does not adversely affect egg production and egg weight.     

Responses of laying hens to a low‐protein diet supplemented with essential amino acids,l‐glutamic acid and/or intact protein

1. Three sequential experiments, each lasting 8 weeks, were carried out on 576 singly‐caged light hybrids.

2. In experiment 1 egg production was 84% using a conventional control diet, 61% with a basal low‐protein diet, and 79% with the basal diet supplemented with 10 essential amino acids + L‐glutamic acid (GA).

3. In experiment 2 supplementation with lysine and methionine (L + M) alone increased egg production significantly from 54 to 72%, compared with 83% with the conventional diet.

4. In experiment 3 egg production was 55% with the basal diet, 71% with the basal diet + L + M, 75% with a diet containing 141 g protein/kg + L + M, and 73% with the conventional diet.

5. In all three experiments supplementation with GA alone either gave no significant response or a depression in production.

6. Daily intakes of 1.24 g nitrogen as non‐essential amino acids and 13 to 14 g total crude protein per bird resulted in good egg production. Supplementation of the basal diet with L + M resulted in a daily intake of 413 mg methionine/bird day which was considered adequate, and a daily intake of 710 mg lysine which was considered slightly inadequate.     

A comparison of the energy and nitrogen metabolism of broilers selected for increased growth rate,food consumption and conversion of food to gain

1. Calorimetric measurements were made on 5‐week‐old male chickens sampled from the third generation of three lines selected for either increased live‐weight gain (W), food consumption (F), or food conversion efficiency (E). A control line (C) was also measured.

2. Food intake and food conversion ratio were greater (P<0.05) in the F line than in the E and C lines.

3. Metabolisability of the diet was 0.8% higher in the E line than in the other lines.

4. Metabolisable energy (ME) intake and heat production were greater (P<0.05) in the F line than in the E and C lines, and energy balance was greater (P<0.05) in the F than in the W and E lines.

5. During starvation, excreta energy and heat production were greater (P < 0.05) in the F than the other lines.

6. Availability of ME (net energy) was the same (85%) for all lines but calculated daily maintenance energy requirements (kJ ME/kgW) were W, 860; F, 937; E, 796 and C, 810.

7. By 9 weeks the F line contained more fat and less water than lines E and C.     

The effect of restricting the individual daily energy intake of caged layers on the efficiency of egg production

Two experiments are described in which the daily metabolisable energy intake of laying hens fed a concentrated diet (ME = 3550 kcal/kg) was restricted on an individual hen basis. Performance on this diet was compared with that of hens fed a high‐energy diet (ME = 2690 kcal/kg). In experiment 1 medium‐weight hybrid pullets were used and in experiment 2 two light‐weight hybrid strains were used.

In both experiments maximum egg production was obtained from the birds fed the high‐energy diet ad libitum. Restriction of the concentrated diet caused a significant reduction of body weight gain and a statistically insignificant fall in the total weight of egg product and in percentage production in both experiments.

Restriction of the concentrated diet caused improvements of 22 and 18 per cent in the efficiency of utilisation of metabolisable energy in experiments 1 and 2 respectively.

The data are discussed in relation to the relevant literature and the current cost of concentrated sources of energy.     

The nutritional value of salseed (Shorea robusta) meal for growing chicks

1. Salseed meal contains 98 g crude protein, 22 g ether extractives, 450 g available carbohydrate and 117 g tannins per kg.

2. From the chemical analysis the metabolisable energy (ME) content of salseed meal would be expected to be 11.22 MJ/kg. In vivo assay with chicks yielded values considerably less than this, 7.1 MJ/kg being found at an inclusion rate of 150 g/kg diet.

3. As the inclusion rate of salseed meal was increased to 300 g/kg, dietary ME and the digestion and retention of dietary protein decreased.

4. More than 50 g salseed meal/kg in the diet of chicks resulted in poor growth rate and food conversion.     

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.     

Calorimetric measurements of the energy and nitrogen metabolism of Japanese quail

1. Respiration calorimetry measurements were made over 4 d on normally‐fed groups of 10 male or 10 female quail during three periods commencing at 12, 19 and 26 d of age. Carcass compositions were determined on groups of birds of each sex at 2 and 5 weeks of age.

2. Expressed per unit body weight, food and metabolisable energy (ME) intake and weight gain decreased between 2 and 3 weeks of age, but remained constant thereafter.

3. No differences were observed between sexes for any variable measured. Efficiency of utilisation of ME for energy retention was only 0.33. This was mainly because the majority of energy was retained as protein tissue.

4. Nitrogen (N) retention (g/d) increased with increasing dietary N intake but when expressed as a proportion of N intake, declined from 0.46 at 2 weeks to 0.33 at 4 weeks. Fat retention increased substantially during week 4.

5. Carcass analyses showed that fat, protein and ash were higher for quail at 5 weeks than at 2 weeks of age. At 5 weeks carcass fat was only 60 g/kg.     

Influence of an enzyme cocktail and phytase individually or in combination in Ven Cobb broiler chickens

1.?An experiment (21 d) was conducted to determine if the response of chicks to a cocktail of xylanase, amylase, and protease (XAP) or Escherichia coli-derived phytase individually or in combination when fed a nutritionally marginal maize–soybean meal diet is age-dependent.

2.?A total of 250 one-day-old Ven Cobb broiler chicks were allocated to 5 dietary treatments in a randomised complete block design. The treatments were as follows: (1) positive control with supplemental inorganic P; (2) negative control (NC) marginal in P and ME; (3) NC plus XAP to provide (per kg of diet) 650, 1650 and 4000 U of xylanase, amylase, and protease, respectively; (4) NC plus phytase added to provide 1000 phytase units/kg; and (5) NC plus a combination of XAP and phytase.

3.?Low ME and P in the NC diet depressed weight gain and gain:feed. A cocktail of XAP alone did not improve performance, but phytase supplementation improved weight gain. The enzymes were additive in their effects on growth performance.

4.?The enzymes had no effect on ileal digestible energy. Ileal N digestibility was higher in diets with XAP or phytase individually compared with NC. Both phytase and XAP individually and in combination improved ileal P digestibility compared with NC.

5.?Total tract nutrient retention and ME increased as the birds grew older. There were age × diet interactions in total tract retention of P and Ca; improvement in P retention due to phytase use decreased by 50% as the chicks matured.

6.?The current study shows that a combination of XAP and phytase improved performance, but the enhancement in performance appears to be due mainly to phytase. Both XAP and phytase were effective in improving P digestibility and retention of chicks receiving nutritionally marginal maize–soybean meal.

7.?The data also showed that the chicks benefited more from the enzyme addition at a younger age and that the contribution of the enzymes to nutrient retention decreased with age in chickens.     

Effects of dietary supplements on the nutritive value of jack beans (canavalia ensiformis) for the young chick

1. Two experiments were conducted with young chicks to examine the efficacy of dietary supplements of amino acids, creatine and potassium acetate in the alleviation of adverse effects of auto‐claved jack beans (AJB).

2. Creatine supplementation of AJB diets markedly enhanced the efficiencies of food and nitrogen utilisation of chicks, restoring these indices to control values. The improvement in nitrogen utilisation was enhanced further on providing creatine with a mixture of 2‐aminoiso‐butyric acid, arginine and lysine.

3. Potassium acetate induced striking improvements in the nitrogen retention efficiencies of chicks fed on AJB diets.

4. Liver weights, as a proportion of body weight, generally increased on feeding AJB diets, the effects being marked with the AJB diet supplemented with arginine and lysine.

5. Hepatic urea concentrations were elevated in all groups receiving AJB. Canavanine, a toxic amino acid component of AJB, could not be detected in acid hydrolysates of livers from chicks fed this legume.

6. Temperature and the volumes of water employed in the preparation of AJB are important determinants of its nutritional value.     

Metabolisable energy and digestible nutrient contents of brewers grains and glucose for the young Turkey

1. The metabolisable energy (ME) contents of dried brewers grains and of dried brewers grains with yeast were 5.51 +0.69 and 7.20 ±0.69 MJ/kg dry matter or 0.25 + 0.03 and 0.34 + 0.03 of their respective gross energy contents.

2. In these respective ingredients, the apparent digestibility coefficients of protein were, 0.66 + 0.08 and 0.69 + 0.08; of fat, 0.49 + 0.16 and 0.64 + 0.16; of dry matter 0.14 + 0.05 and 0.24 + 0.05, while fibre and nitrogen‐free extract (NFE) were not digested.

3. In balanced low‐protein diets formed by adding glucose to a high‐protein diet, the ME content of glucose was 15.12 + 0.44 MJ/kg dry matter or 0.97 ± 0.03 of its gross energy content, while the apparent digestibility coefficient of its NFE was 0–99 + 0–02, and that of its dry matter was 1.02 + 0.04.

4. Imbalancing diets greatly by removing or adding glucose to a balanced diet did not affect the nutrient digestibility or the ME of glucose, indicating that the basic assumption of linearity of these measurements with dietary content of the test ingredient was valid.     

Efficiency of utilisation by growing chickens of the energy of dietary fat and oil

1. Calorimetric studies were conducted with groups of five chickens to determine if availability of metabolisable energy (ME) changed with increasing concentrations of corn oil or tallow added to six diets.

2. There was no significant difference between the diets in the regression equations relating ME intake and energy retention. There was a slight increase in partial efficiency with increasing ME intake, from 82% at the mean daily intake of 1 874 kJkg W ^0.75 to 85% at the highest intake of 2 300 kJ/kg W^0.75.

3. Energy retention was greatest at the highest concentration of tallow (140 g/kg) in the diet; there was an indication that availability of ME may be greater for tallow than for oil at a similar ME inclusion rate when compared at the mean daily intake of ME. Without any lipid in the diet, partial efficiency was 77% and energy retention was lower than on the diets with added oil or fat.     

Influence of activity and dietary energy on broiler performance,carcase yield and sensory quality

1. A total of 2560 male and female Ross broilers were raised to 42 days of age in a 2 × 2 treatment factorial arrangement experiment to investigate the influence of different degrees of physical activity and dietary energy on broiler performance, abdominal fat content, carcase yield and sensory quality.

2. Vertical fans were used to force the treatment birds to walk 3 to 4 times as far as the normal activity birds; birds were fed a normal and a high energy diet (12.55 compared with 13.81 MJ ME/kg) with the same energy/protein, energy/lysine and energy/methionine + cystine ratios.

3. High activity birds had greater body weight ( + 4.1%), food intake ( + 5.1%) and ME intake ( + 5.1%) than normal activity birds. Birds receiving high energy diet had a lower food conversion and food intake than birds receiving normal energy diet. There were no significant differences in body weight or ME intake between birds with different diets.

4. Slaughter yields, both absolute and relative to live body weight, were affected by activity or dietary energy to varying degrees. Breast meat was increased with more activity. The absolute weight of abdominal fat was independent of activity and in males the relative weight of abdominal fat was decreased in high activity birds.

5. Different degrees of activity and dietary energy had only minor influences on broilers' sensory quality.