D. J. W. Lee

Effects on chick growth of adding various non-protein nitrogen sources or dried autoclaved poultry manure to diets containing crystalline essential amino acids.

Synopsis Female broiler chicks were offered semi‐purified diets containing crystalline essential amino acids, including proline, supplemented with various nitrogen sources. Individual final body weights, food consumption and food conversion efficiencies (FCE) were measured. In the first experiment 70 1‐d‐old chicks were given one of seven diets for 21 d; basal (1A) or basal plus: 12% l‐glutamic acid (1B), 17.05% monoammonium citrate (1C), 9.23% diammonium citrate (1D), 6.61% triammonium citrate (TAC) (1E), 2.45% urea (1F) or 4.05% triammonium phosphate and 12.56% calcium lactate (1G). Using body weight at 21 d and FGE as measures of the effectiveness of the various nitrogen sources the orders were 1E (171 g), 1B (154 g) > 1D (131 g), 1G (123 g), 1F (118 g) >basal (89 g) >1C (66 g), (P 1G (0.346), 1F (0.329), 1D (0.319) > basal (0.269) > 1C (0.192), (P < 0.05), respectively. In the second experiment 70 7‐d‐old chicks were offered one of seven diets for 14 d; basal (2A) o...

Effects on chick growth of adding glycine, proline, glutamic acid or diammonium citrate to diets containing crystalline essential amino acids

Synopsis Purified diets, designed to supply a balanced sufficiency but not excess of essential amino acids, were supplemented with glycine, glutamic acid, proline or diammonium citrate (DAC) and fed to broiler chicks from the 7 d stage. Slow growth was obtained unless the diet was supplemented with 1 % L‐proline, confirming other work which suggests that proline should be reclassified as an essential amino acid for the chick. Increasing the level of glycine in the diet from 1 ‐o to 1 ‐6% did not result in a marked growth response. Adding 11–07% DAC to the diet gave a significant growth response and a significant increase in the plasma level of amino acids. The utilisation of DAC was equivalent to that of an isonitrogenous supplement of glutamic acid in one experiment, but was significantly poorer than that of glutamic acid in another. A significant linear regression of live‐weight gain on nitrogen intake was derived (r = 0–8582): growth was better on a practical than on any of the purified diets used but ...

Battery gage shape: The laying performance of medium‐ and light‐body weight strains of hens

1. One thousand two hundred and ninety‐six medium‐ and 1296 lightweight hens were housed, four to a cage, in deep (conventional) cages, 405 mm wide by 460 mm deep, or shallow cages, 610 mm wide by 305 mm deep, between 18 and 70 weeks of age. The performance of the hens during different periods of the laying stage and over the full laying year was measured. 2. Egg number per medium‐weight hen housed in shallow cages was significantly higher than of hens housed in deep cages between 18 and 30 weeks and 31 and 42 weeks. Thereafter significant differences were not found. With the light‐weight hens the increase was significant only in the 18‐ to 30‐week period. Apart from the 19‐ to 30‐week period hens of both strains housed in shallow cages consumed significantly less food than those in deep cages, the reduction over the full year being about 4%. In all periods the hens housed in the shallow cages converted food more efficiently. Gage shape had no significant effect on mortality. 3. The incidence of hair‐crac...

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

Synopsis 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...

Urease activity in the digestive tract of the chick and its role in the utilisation of urea as a source of non-amino nitrogen.

Urease activity was found in caecal contents (about 10 mg urea metabolised/g h) and crop contents (about 0-5 mg urea metabolised/g h):there was very low activity in the contents of the colon but none in the rest of the digestive tract. 2. The urease activity of the crop contents was not bacterial in origin but the soyabean meal contained in the diet was found to have comparable activity. 3. Diets low in non-essential nitrogen and based on soyabean, fish meal or fish meal plus 0-2% jack bean urease, did not support higher growth rates when supplemented with urea. 4. The livers of chicks fed on the diet containing fish meal, urea and urease had significantly higher concentrations of free non-essential amino acids than those of chicks fed on the same diet but with urease excluded This suggested that dietary urease affects the availability of ammonia for the synthesis of non-essential amino acids but not for growth.

Growth of broilers fed on diets containing dried poultry manure

Synopsis Sixty 7‐d‐old male broiler chicks were housed in individual metabolism cages and offered one of six purified diets for 14 d. The diets were formulated to have the same ME contents but had different nitrogenous supplements: diet A, was the basal diet, containing PRG essential amino acid (EAA) mixture equivalent to 15 g N/kg; B, basal+12% glutamic acid (GA); C, basal plus EAA mixture equivalent to EAA content of 20.09% DPM; D, basal + EAA+12% GA; E, basal + 20.09% autoclaved DPM; F, basal + 20.09% unautoclaved DPM. The rank order of final body weights at 21 d of chicks fed on these diets were D(292 g) > B(258 g), (F254 g), E(253 g) > C(206 g) > A(180 g), (P<0.05). Chicks fed on diet C had better food conversion efficiencies (FCE) than those fed on diet A (0.449 and 0.374 respectively) and D was better than B (0.592 and 0.533 respectively). In a second experiment, carried out under field trial conditions using commercial‐type diets formulated to contain DPM, 24 groups, each of about 40 male or femal...

Enzyme studies with the livers of chicks fed semi-synthetic diets containing crystalline amino acids and diammonium citrate.

Synopsis The levels of glutamate dehydrogenase [NAD(P)], (GDH), aspartate trans‐aminase (AspT) and alanine transaminase (AlT) were measured in livers from chicks fed on a semi‐synthetic diet containing crystalline essential amino acids as the sole nitrogen source (diet A). The effects of a supplement of 12.0% glutamic acid (diet H) or 11.07% diammonium citrate (DAC) (diet B) or 12.0% glutamic acid plus 1.0% proline with an additional 0.6% glycine (diet C) on these enzymes were studied and the results compared with the levels found for control chicks given a typical diet based on cereal protein (diet J). The abilities of livers from chicks given diets A, B and C to synthesise [14C] glutamic acid from [14C]2‐oxoglutaric acid and diammonium citrate (DAC) were assessed. The levels of GDH, AspT and AlT found in the livers of chicks given the control diet were 54.1, 966 and 123.7 units/mg protein respectively. Non‐essential nitrogen added as glutamic acid or as DAC did not cause induction of the enzymes studied...

The growth of broiler chickens fed low‐protein diets containing triammonium citrate, diammonium hydrogen citrate and autoclaved dried poultry manure

Synopsis Three experiments were carried out using male broiler chicks from 1 to 3 weeks of age. The birds were housed in individual metabolism cages at 1 week of age, having previously been in tiered brooders. In experiment 1, 36 birds were offered one of six experimental diets based on glucose‐ and cellulose‐diluted commercial broiler mash. The six diets were supplemented with graded levels of triammonium citrate (TAC) at the expense of cellulose such that diet 1B contained no TAC and diet 1F contained 6.4% TAC. In experiment 2, 72 birds were offered one of six diets, similar to those used in experiment 1 with the exception that they were supplemented with graded levels of diammonium hydrogen citrate (DAHC). In experiment 3, 72 birds were offered one of six diets which were based on the same diluted broiler mash but which had been supplemented with graded levels of autoclaved dried poultry manure (ADPM) at the expense of glucose. Diet 3B contained no ADPM whereas diet 3F contained 20% ADPM. All birds wer...

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.

The effect of carbohydrate source and energy‐to‐amino acid ratio on the growth of chicks given diets containing crystalline amino acids

Synopsis In each of two experiments chicks aged 7 d were housed individually and given purified diets containing crystalline amino acids for a period of 13 or 14 d. In the first experiment a comparison was made of four amino acid mixtures and of starch plus sucrose as a carbohydrate source. It was found that an amino acid mixture formulated on the basis of current recommendations for overall amino acid balance and for the high ME value of purified diets (diet G), gave superior growth and efficiency of food conversion. The amount of food eaten was greater with diets containing starch plus sucrose than with starch alone and as a result growth was improved. Carbohydrate source had no significant influence on the efficiency of food conversion. In the second experiment diet G was modified by reducing the level of ME with a concomitant reduction in the level of all amino acids. The effect of modifying a comparable diet developed at the University of Illinois by lowering the ME level while keeping the level of a...