Antioxidant status of turkey breast meat and blood after feeding a diet enriched with histidine.

The objective of this study was to investigate the effects of 1) spray dried blood cells rich in histidine and 2) pure histidine added to feed on the antioxidant status and concentration of carnosine related components in the blood and breast meat of female turkeys. The experiment was performed on 168 Big7 turkey females randomly assigned to 3 dietary treatments: control; control with the addition of 0.18% L-histidine (His); and control with the addition of spray dried blood cells (SDBC). Birds were raised for 103 d on a floor with sawdust litter, with drinking water and feed ad libitum. The antioxidant status of blood plasma and breast muscle was analyzed by ferric reducing ability (FRAP) and by 2,2-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging ability. The activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) was analyzed in the blood and breast meat, with the content of carnosine and anserine quantified by HPLC. Proximate analysis as well as amino acid profiling were carried out for the feed and breast muscles. Growth performance parameters also were calculated. Histidine supplementation of the turkey diet resulted in increased DPPH radical scavenging capacity in the breast muscles and blood, but did not result in higher histidine dipeptide concentrations. The enzymatic antioxidant system of turkey blood was affected by the diet with SDBC. In the plasma, the SDBC addition increased both SOD and GPx activity, and decreased GPx activity in the erythrocytes. Feeding turkeys with an SDBC containing diet increased BW and the content of isoleucine and valine in breast muscles.

Effect of various sources and levels of iodine, as well as the kind of diet, on the performance of young laying hens, iodine accumulation in eggs, egg characteristics, and morphotic and biochemical indices in blood.

Young hens were fed over a period of 150 d with 2 kinds of diets including corn and soybean meal or corn, soybean, and rapeseed meal. Diets were enriched with potassium iodide (KI) or potassium iodate (KIO3) as an I source in amounts equal to 1, 3, or 5 mg of supplemented I/kg of feed. The hen performance, egg quality, hematological and morphotic indices in blood, hepatic enzyme activity, lipid indices in blood serum as well as I accumulation in wet egg content were determined. Introduction of 00-variety rapeseed meal into the diet improved the laying rate and feed conversion (P < 0.05); however, better egg weight was noted by feeding the hens with a diet without rapeseed meal. Use of KI as an I source enhanced the egg weight. The increased I level in the diet had an equivocal influence on egg weight, improved the feed conversion per 1 kg of eggs, and decreased the proportion of damaged eggs. The use of corn, soybean, and rapeseed meal in hen diets significantly improved yolk color; similar results were noted after an increase in I levels in the diets after 3 mo of feeding. Hematological indices of hen blood demonstrated significantly higher red blood cells numbers and hemoglobin concentrations with the use of KI. The use of a diet containing rapeseed meal led to an enhancement of hepatic enzyme activity, especially of alkaline phosphatase (P = 0.007). Lipid metabolism indices were not influenced by the kind of diet or the I source or level. The accumulation of I in wet egg content was negatively influenced by the use of a diet containing rapeseed meal (P = 0.000). The application of KI as an I source enhanced (P = 0.003) the accretion of I in eggs after 5 mo of treatment. Enhanced I supply significantly increased accumulation of I in eggs (P = 0.000) after 3 and 5 mo of the experiment from 260 and 310 to 1,011 and 1,256 µg/kg of wet egg content, respectively.

Influence of different histidine sources and zinc supplementation of broiler diets on dipeptide content and antioxidant status of blood and meat.

1. The objective of this study was to investigate how a diet containing spray-dried blood cells (SDBC) (4%) with or without zinc (Zn) would affect the concentration of two histidine heterodipeptides and the antioxidant status of broiler blood and breast muscles. 2. The study was carried out on 920 male Flex chickens randomly assigned to 4 dietary treatments: I - control, II - diet I with SDBC, III - diet I with SDBC and supplemented with Zn and IV - diet I supplemented with L-histidine. Birds were raised on floor littered with wood shavings, given free access to water and fed ad libitum. Performance indices were measured on d 1, 21 and 42. 3. The activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase was analysed in plasma, erythrocytes and muscle tissue. The total antioxidant capacity of plasma and breast muscles was measured by 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, as well as by ferric reducing antioxidant power (FRAP). Carnosine/anserine content of meat and plasma were determined using HPLC. Diets and breast muscles were analysed for amino acid profile and selected microelement content. 4. Histidine supplementation of the diet increased glutathione peroxidase activity in plasma and superoxide dismutase activity in erythrocytes. Moreover, the addition of SDBC or pure histidine in the diet increased histidine dipeptide content and activated enzymatic and non-enzymatic antioxidant systems in chicken blood and muscles. However, it led to lower growth performance indices. 5. The enrichment of broiler diets with Zn increased the antioxidant potential and the activity of superoxide dismutase in plasma, which was independent of the histidine dipeptide concentration. Zn supplementation combined with SDBC in a broiler diet led to the increase of superoxide dismutase and glutathione peroxidase activity, but it did not affect the radical-scavenging or ferric iron reduction abilities of muscles.

Antioxidation status and histidine dipeptides content in broiler blood and muscles depending on protein sources in feed.

One-day-old chickens were fed mixtures containing different raw materials (fish by-products meal, porcine blood cells meal, blood meal, wheat gluten, fodder yeast), as a source of histidine and ß-alanine - components of carnosine. Control birds were administered a feed mixture, in which soy bean meal was the main protein source. The bodyweight, feed consumption and conversion, antioxidant characteristics and histidine dipeptides content in blood and muscles, and also amino acid composition of chicken meat on day 34 post-hatch were recorded. The best (p < 0.05) performance and feed conversion were observed in chickens fed mixture containing porcine blood cells meal. In blood plasma of control chickens, a significantly (p < 0.01) higher ability to scavenge DPPH radicals was found. However, the highest catalase activity in erythrocytes was determined in chickens fed mixtures with blood by-products. Insignificant differences in both carnosine and anserine levels in plasma between treatments were noted. Breast muscles from control birds were characterized by lower activity of glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) (p < 0.05; p < 0.01), than those from chickens fed blood by-products. Improved ability to reduce ferric ions (FRAP) (p < 0.01) and carnosine content in meat from chickens fed blood cell meal were recorded. No direct relations between amino acids content in feed mixtures and in meat were observed.

Use of spray-dried porcine blood by-products in diets for young chickens.

Spray-dried porcine blood plasma (SDBP) or blood cells (SDBC) at amounts of 20 or 40 g/kg were included to the feed mixtures that were given to young chickens within 1-28 (Exp. 1) or 1-30 (Exp. 2) days post-hatch. In comparison with the group fed mixtures containing plant components, chickens fed mixtures supplemented with 40 g/kg of SDBP significantly (p < 0.01) increased the body weight estimated on 14 day of life (Exp. 1). At the age of 28 or 30 days post-hatch, the body weight was improved significantly (p < 0.01 or 0.05) in both experiments. Significant differences (one-factorial anova) in feed conversion among particular feeding groups were stated in Exp. 1 only; however, calculations using two-factorial anova show insignificant differences depending on the used animal meal. In selected blood parameters (IgG, Ht, Hb), insignificant differences between feeding groups were stated. The use of SDBP in feed mixture significantly increased the Na retention in both experiments, and K accretion in Exp. 1 only. Application of SDBC and 40 g/kg of SDBP significantly or insignificantly improved Fe retention. Insignificant diversification of apparent ileal digestibility of nutrients was stated; the crude fat was significantly better digested in treatments fed mixtures with animal meals but kind of animal meal was without any significant effect. Significant differences in digestibility of amino acids were recorded for Pro, Cys, Val, His, Lys and Arg. In chickens fed mixture with SDBC, higher coefficients of apparent digestibility of Cys, Val and His (Exp. 1) and Cys and His (Exp. 2) than in other feeding groups were obtained. The kind of used blood by-products has not affected the histological structure of intestine wall.

Chemical composition and biological value of spray dried porcine blood by-products and bone protein hydrolysate for young chickens.

The chemical composition of spray dried porcine blood by-products is characterised by wide variation in crude protein contents. In spray dried porcine blood plasma (SDBP) it varied between 670-780 g/kg, in spray dried blood cells (SDBC) between 830-930 g/kg, and in bone protein hydrolysate (BPH) in a range of 740-780 g/kg. Compared with fish meal, these feeds are poor in Met and Lys. Moreover, in BPH deep deficits of Met, Cys, Thr and other amino acids were found. The experiment comprised 7 dietary treatments: SDBP, SDBC, and BPH, each at an inclusion rate of 20 or 40 g/kg diet, plus a control. The addition of 20 or 40 g/kg of the analysed meals into feeds for very young chickens (1-28 d post hatch) significantly decreased the body weight (BW) of birds. Only the treatments with 40 g/kg of SDBP and SDBC showed no significant difference in BW as compared with the control. There were no significant differences between treatments and type of meal for feed intake, haematocrit and haemoglobin concentrations in blood. Addition of bone protein and blood cell meals to feed decreased the IgG concentration in blood and caused shortening of the femur and tibia bones. However, changes in the mineral composition of bones were not significantly affected by the type of meal used. The blood by-products, which are rich in microelements, improved retention of Ca and Cu only. In comparison to control chickens, significantly better accretion of these minerals was found in treatments containing 20 g/kg of SDBP or 40 g/kg of SDBC. Great variability in apparent ileal amino acid digestibility in chickens was determined. In this respect, some significant differences related to the type of meal fed were confirmed for Asp, Pro, Val, Tyr and His. In general, the apparent ileal digestibility of amino acids was about 2-3 percentage units better in chickens fed on diets containing the animal by products than in control birds.

Effect of sweet chestnut tannin (SCT) on the performance, microbial status of intestine and histological characteristics of intestine wall in chickens.

1. In experiments carried out with 950 one-day-old male chickens, the effect of tannin supplementation (0, 250, 500 and 1000 mg/kg) on performance, microbial status of chickens small intestine and colon of 28- and 41-d-old chickens, as well as histological changes of jejunum walls at 41 d and carcase quality were determined. 2. Application of 250 or 500 mg of sweet chestnut tannin per kg of feed had an insignificant effect on body weight and feed conversion of 41-d-old chickens (30 and 26%) in comparison to control birds. The highest tannin supplement (1000 mg/kg) reduced final body weight. 3. No effects of tannin supplementation on feed conversion and carcase quality were found. 4. Addition of tannin increased dry matter content of the litter by 88 (Group II) and 77% (Group III) when compared to control. 5. Higher doses of tannins significantly reduced the number of E. coli and coliform bacteria in small intestine of 28-d-old chickens; in other microorganisms great variability of microbial populations in small intestine and colon were observed. 6. The histologies of jejunal walls in chickens of control, II (250 mg/kg) and III (500 mg/kg) groups were similar. The structure was characteristic of correctly developed and functioning tissues and the villi were formed correctly. Tannin applied at the highest dose (1000 mg) slowed down the proliferation rate in the mother-cell zone. Single cells and enterocyte complexes showed the features characteristic of degradation processes. These unfavourable symptoms indicated some disturbances in intestinal wall morphology and function.

Dynamics of yolk sac content absorption and intestine development in ducklings fed mixtures with increasing dietary methionine level.

The experiment was carried out with ducklings fed-control feed mixture (Met level 0.3%) and mixtures supplemented with dl-methionine at the dose of 0.03 (II); 0.07 (III) 0.12 (IV) and 0.18% (V). In 5 h post-hatch (12 birds) and on days 3, 4, 6 always 18 birds were taken out from each treatment and killed, then the yolk sac (YS) and intestine were removed. The weight and chemical composition of YS residues (in them also amino acids) were analysed. Moreover on days 1, 3, 4 and 6, the amino acid pattern of YS residual protein was elaborated as well as length and weight of intestine were recorded. Increased doses of supplemental Met improved body weight gain after 4 days of ducklings life. All determined parameters were not affected by treatment. Development of intestines, yolk sac weight and yolk sac composition (DM, fat, protein, amino acid composition) changed with age; however, without any clear effect from dietary methionine level. No differences between sex and analysed parameters were stated.

Effect of increased methionine level on performance and apparent ileal digestibility of amino acids in ducks.

The experiment was conducted with 960 one-day-old ducklings fed mixtures (I control - 0.28% methionine) additionally supplemented with DL-methionine (DL-Met) at amounts: 0.03% (group II), 0.07% (III), 0.12% (IV) and 0.18% (V). The performance, carcass quality and apparent ileal digestibility of amino acids as the criterions of methionine (Met) effectivity were considered. The analysis of growth and development of ducks as an effect of diversified DL-Met supplements indicate that increased content of this amino acid in the diets has not affected clearly the performance parameters. The body weight of 21-day-old ducklings was significantly affected only by the level of 0.12% of added Met in comparison to control group. On day 42, the differences among groups were negligible; only the addition of 0.12% DL-Met has increased the body weight by 2.4% when compared with control (p > 0.05). Feed conversion estimated for a period of 1-42 days has not been influenced by Met supplementation. The indistinct, however, visible tendency of better ileal amino acids' apparent digestibility (for Asp.a.,Thr, Ser, Glu, Lys) was noted in the groups fed supplemented diets. Application of 0.07% and 0.18% of DL-met, has significantly (p < 0.05) improved the coefficient of cysteine (Cys) apparent ileal digestibility; however, the improvement of Met apparent ileal digestibility has been achieved by the addition of 0.18% Met. The mortality of ducklings in the experiment was very low and varied between 3.15% (II) and 0.0% (groups I and III). In general, application of 0.12% of DL-Met to mixture containing 0.28% Met had positive effect on the productive output of birds and also improved the apparent ileal digestibility of Cys and Met.

Harmful substances in legume seeds--their negative and beneficial properties.

The leguminous seeds constitute a valuable source of feed and dietary protein, however, they contain also many different substances that are recognised as antinutritive factors. This review deals with harmful substances and composition of leguminous seeds, their profitable and negative activity considering also the effect on physiology of digestion, intestinal functions and health of animals.

Influence of diet type on the inclusion of plant origin active substances on morphological and histochemical characteristics of the stomach and jejunum walls in chicken.

Three hundred and thirty-six 1-day-old male Hubbard HI-Ye broiler hybrids, kept in battery cages, were fed with diets based on maize (groups I and II) or wheat and barley (groups III and IV) and supplemented with or without plant extract (XT* 100 mg/kg) containing 5% carvacrol, 3% cinnamaldehyde and 2% of capsicum oleoresin. The morphological and histochemical examinations were carried out on days 21 and 42 of bird's age. The middle part of glandular part of the stomach and 30 mm long segment from the central part of the small intestine (jejunum) were taken out and then prepared for morphometrical and histochemical assays. Mobilization of mucocytes in superficial epithelium of the glandular stomach and increased secretion of neutral mucopolysaccharides and small amounts of sialomucins with or without local cell disruption with releasing of large amounts of mucus were observed in both 'grain' groups of 21-day-old birds fed with extract. In some animals, particularly those fed mixtures with plant extract, the folds of the proventriculum mucosa were fused into large, unshaped structures. In groups fed with plant extract the mucus secretion intensity and accumulation inside cells of the gastrointestinal mucosa were slightly higher. Morphological changes on gastrointestinal mucosa observed in young chickens fed XT were reduced in older animals. The results of this study showed that the increased releasing of large amounts of mucus and the creation of a thick layer of mucus on glandular stomach and wall of jejunum in chickens fed diets with plant extract could suggest villi-related protective properties of the use of the carvacrol, cinnamaldehyde and capsaicin mixture. This can explain the reduced possibility of adhesion to epithelium and number of Escherichia coli, Clostridium perfringes and fungi in the intestinal content of bird fed with XT supplemented diet. In morphometrical parameters of depth of jejunum crypt and height of villi, the influence of kind of grain and extract supplementation was observed in 21-day-old chickens only. The significant interaction between higher jejunum wall villi layer was observed only in chickens fed on maize diet supplemented with plant extract.

Use of active substances of plant origin in chicken diets based on maize and locally grown cereals.

1. A total of 336 Hubbard Hi-Y broiler hybrids were fed from d 1-41 on diets based on maize or wheat and barley which were supplemented (or not) with 100 mg/kg plant extract consisting of capsaicin, cinnamaldehyde and carvacrol. 2. Body weight was not enhanced, but feed conversion improved by 4.2% on the maize diet and 2.0% on the wheat and barley diet. 3. Plant extract addition enhanced the breast muscle proportion of empty body weight by 1.2% in comparison to control birds. 4. The apparent ileal digestibility of nutrients (crude protein, fibre and amino acids) was not significantly better in birds fed on supplemented diets than in the control group. 5. Reduction of E. coli, Clostridium perfringens and fungi and increase of Lactobacillus spp. were observed in the 41-d-old chickens from the supplemented groups. 6. An increase in the lipase activity in pancreas and intestine wall was found in older birds fed on the plant extract supplemented diets.

Dynamics of yolk sac resorption and post-hatching development of the gastrointestinal tract in chickens, ducks and geese.

Under similar environmental conditions, 100 male Shaver-Starbro hybrid chickens, 100 male Mulard cross-line ducklings and 100 male Landaise goslings kept in 30 metabolic cages from the first day of life (10 birds of each species separately per cage) were chosen for the study. The animals were fed semi ad libitum diets with crude protein content and energy density similar to that used for poultry species, avoiding feed residues. During the first 21 days of life they received starter diets and from day 22 to 42 grower diets. Maize accounted for 23-40% and barley constituted 10-18%. Wheat accounted for 20.0% in starter diets and 10-18% in grower diets. Resorption of yolk sac residues, performance, development of the intestinal tract in young chickens, ducklings and goslings were assessed. During the first 5 days of life intensive absorption of yolk sac ingredients was observed. On day 7, residues of the yolk sac were found in more than 30% of chickens compared with approximately 10% in geese. In ducklings residues of the yolk sac were not found. On day 16 unabsorbed yolk sacs were found in approximately 10% of chickens. Liver and pancreas weighed the highest in geese and in ducks; in chickens the weight of these organs was significantly lower (p < 0.01). The relative values calculated to 100 g of metabolic body weight show that the average small intestine in chickens was significantly longer (p < 0.01) than in ducks or geese. The intestinal tract developed earlier in the chicken than in the water fowl.

Aspects of development of digestive activity of intestine in young chickens, ducks and geese.

The experiment comprised 100 chickens, 100 ducks and 100 geese fed diets based on mixed grains of maize, barley and wheat. Nutrient concentrations in the mixtures were in accordance with the requirements of poultry species. The birds were kept in metabolic cages from the 1st up to the 42nd day of life. The measurements of body weight, activity of alpha-amylase and lipase in pancreatic tissue, enzymatic activity of intestinal wall cells, parameters of carbohydrate fermentations, ileal and total amino acids digestibility were conducted on the 1st, 3rd, 5th, 7th, 28th and 42nd day of life or on the 14th, 28th and 42nd day of life. The pancreas alpha-amylase activity in chickens during the whole period was quite constant; in ducks and geese it was very low, but from the 28th day a dynamic increase in the activity of the pancreatic enzymes was observed in these birds. The activity of lipase was low but from the 28th day of experiment an increase was noted and was much higher in waterfowl than in chickens. The highest caecal concentration of SCFA (Short chain fatty acids) (in total high) was noted in chickens; these values were slightly lower in geese and ducks. A high (70%) ileal amino acids digestibility was seen in very young chickens; during the period of 15-42 days this value amounted up to 73%. In geese, the obtained values were 63% and in ducks 43-61%, with a mean of 55%. Faecal digestibility of amino acids had a mean of up to 86% for all species but the digestibility of single amino acids such as cystine, glycine, histidine and tyrosine was diversified and relatively lower than the others.

Development of the gastrointestinal tract and digestibility of dietary fibre and amino acids in young chickens, ducks and geese fed diets with high amounts of barley.

The experiment comprised of 50 chickens, 40 ducks and 30 geese fed a diet containing 40% barley. Birds were kept in metabolic cages from 1 to 42 days of age. A balance trial was carried out during the last week of the bird's life and the apparent digestibility of nutrients was determined. At 21 and 42 days of age 12 animals per species were killed. The absolute length of intestines followed the live weight (LW) of the animals. In relation to metabolic LW (kg(0.67)), the total length was significantly higher in chickens and geese than in ducks at 21 days of age, but identical in the three species at 42 days of age. The absolute and relative weights of intestines were smaller in ducks than in chickens and geese both at 21 and 42 days of age. Dietary fibre was digested better by chickens than by ducks and geese (P<0.01). Ileal digestibility of total amino acids amounted to 76% in chickens, 69% in ducks (P>0.05) and only 56% in geese (P<0.01) with relatively low digestibility of methionine (70, 44 and 52%) and lysine (72, 57 and 41%), respectively. The overall tract-faecal digestibility of total amino acids was evaluated on the level of 86% for all three species and indicates a substantial hind gut synthesis of amino acids.

Solvation of Cr3+ cation in water-acetonitrile mixture studied by IR spectroscopy: molecular penetration into the solvation shells.

Infrared spectra of mixtures of water and deuteroacetonitrile containing the Cr3+ cation have been studied as a function of concentration, time and temperature. The CN stretching vibration of CD3CN molecules has been used as a probe of the structural environments. The CN band in the spectra of the solutions is a superposition of four subbands, which may be attributed to CD3CN bound in the first, second, and third solvation shells of the cation and to non-bound CD3CN. The character of changes of the integral intensities of the subbands with time for various H2O:Cr3+ molar ratios are explained by suggesting mechanisms of molecular replacement within the solvation shells of Cr3+.

Novel selective kappa-opioid ligands.

The single-crystal X-ray structures of (-)-dimethyl[(2S)-1-(5,6,7,8- tetrahydro-5-oxonaphthalene-2-acetyl)piperidin-2-ylmethyl ]ammonium chloride, C20H29N2O2+.Cl-(BRL-53001A), and (-)-ethylmethyl[(2S)-1-(5,6,7,8-tetrahydro-5-oxonaphthalene- 2- acetyl)piperidin-2-ylmethyl]-ammonium chloride dihydrate, C21H31N2O2+.Cl-.2H2O (BRL-53188A), have been determined. The two molecules have different conformations in the 1-tetralon-6-ylacetyl residue but the same conformation in the 1-acetyl-2-(dialkylaminomethyl)piperidine moiety. The conformations found are in agreement with the required chemical features for kappa affinity and antinociceptive potency.

Effects of feed antibiotic avoparcine on organ morphology in broiler chickens.

Groups of 90 male broilers each were administered the antibiotic avoparcine mixed into feed in concentrations of 7.5, 10, and 15 ppm and achieved a higher mean body weight than the controls fed without this admixture. At the end of the 70-d fattening period, histological examination was carried out on selected individuals. The small intestine, liver, bursa of Fabricius, thymus, thyroid gland, pancreas, kidneys, heart, and skeletal muscle were observed on paraffin sections stained with hematoxylin and eosin. Cell proliferation was assessed in the liver and small intestine by means of bromodeoxyuridine labeling. The exposure to avoparcine resulted in a decreased cell proliferation in both tissues when compared to controls. In addition, hypertrophy of the hepatocytes and development of reactive lymphoid tissue in the bursa of Fabricius, which occurred in the controls, were absent in the treated animals. These observations indicate that the growth-promoting effect of avoparcine is related to a restriction in the host animals of responses to intestinal bacteria. No adverse pathological changes were observed in the examined tissues, indicating that avoparcine was well tolerated.

[Influence of the cecum, in geese fed diets containing urea, on N-metabolism and digestibility of nutrients and on urea concentration in excrements and blood]. / Einfluss des Caecums der Gans bei Verfütterung harnstoffhaltiger Rationen auf die N-Bilanz und die Verdaulichkeit der Nährstoffe und den Harnstoffgehalt in den Exkrementen und im Blut

Balance experiments were performed on six normal young geese and on six geese with a ligated caecum. The ration consisted of 43.25% barley, 30% sugar beet slices, 20% cellulose, 1.4% maize germ oil, 3% mineral mixture, 1% concentrate of vitamins and growth factors, 1.25% urea and 0.1% lysine. Daily nitrogen balance was similar in the two groups (average 1051 mg in the controls and 1090 mg in the experimental birds). Crude protein digestibility was 82.4 +/- 1.1% in the controls and 84.9 +/- 1% in the experimental birds (a significant difference). The bacterial flora of the caecum seemed to have no effect on crude fibre breakdown. Digestibility was quite low, averaging 5.7% in controls and 4.6% in experimental birds. The proportion of urea discharged in excreta was 50% in controls and 55.7% in experimental birds. Blood urea veraged 21.7 mg/100 g in controls and 22.8 mg in experimental birds (insignificant difference).