The effect of supplementary bacterial phytase on dietary metabolisable energy, nutrient retention and endogenous losses in precision fed broiler chickens.

Thirty-two Ross 308 male broiler chickens were used in a precision feeding assay to investigate the effect of exogenous phytase (EC 3.1.3.26) on dietary apparent metabolisable energy (AME), dry matter digestibility (DMD) coefficient, nitrogen (NR), amino acid and mineral retentions. The excretion of endogenous losses measured as sialic acid (SA) was also determined. Four dietary treatments (control (C), C + 250 FTU (phytase units per kg feed), C + 500 FTU, and C + 2500 FTU) were studied with each treatment replicated eight times in randomised complete block design. Diets were formulated to be nutritionally adequate with the exception of available P content (2.3 g/kg non-phytate P). Over the 48-h collection period, the phytase fed birds retained 29.3 mg more Na and 2.3 mg more Zn (p < 0.05) than the control fed birds, with the relationship between phytase dose and Na and Zn retention being best described by a linear function (p < 0.05 and p < 0.001, for Na and Zn, respectively). Phytase supplementation did not have an effect on dietary AME, DMD and NR. However, increasing the dose of phytase led to a linear increase in dietary amino acid retention (p < 0.05). Dietary phytase decreased total sialic acid excretion in a linear fashion (p < 0.05). It can be concluded that supplementary phytase increases the retention (reduces the excretion) of dietary Zn and Na in broiler chickens. The beneficial effects of the addition of exogenous phytases to poultry diets seems to be mediated through improved dietary nutrients absorption and reduced endogenous losses.

The effects of supplementary bacterial phytase on dietary true metabolisable energy, nutrient digestibility and endogenous losses in precision fed turkeys.

1. A total of 40 female BUT9 turkeys were used in a precision-feeding assay to investigate the effect of dietary phytase on true metabolisable energy corrected for N retention (TME(N)), coefficients of true dry matter (TDMD), mineral, amino acid and nitrogen (TND) digestibilities and the excretion of endogenous mucin, measured as sialic acid (SA). 2. Five treatments were used in this study: control (C), C + 250 phytase units (FTU) per kg feed, C + 500 FTU, C + 2500 FTU, and glucose only for endogenous losses estimation. Diets were formulated to be nutritionally adequate with the exception that the P content was relatively low (3·6 g/kg non-phytate P). 3. Inclusion of phytase increased TND in a quadratic manner with the optimum being achieved at approximately 500 FTU, at which TND was 37 % greater than in the control. The concentration of SA in the excreta decreased linearly with increased phytase supplementation. Dietary TME(N), TDMD and true mineral digestibility coefficients were not significantly affected by phytase supplementation. 4. Phytase inclusion increased digestibility coefficients for indispensable, dispensable and total amino acids in a linear manner. The scale of the response to phytase was greatest with threonine and least with lysine digestibility, suggesting a specific mechanism of action that benefits gut health. 5. The strong negative relationship between secretion of SA and threonine digestibility suggests that a large part of the threonine benefit may be from reduced mucin synthesis. This supports the hypothesis that dietary phytase may play a role in improving the health status of the intestine and, as a result, reduces the maintenance energy requirements of turkeys.

Herbs, thyme essential oil and condensed tannin extracts as dietary supplements for broilers, and their effects on performance, digestibility, volatile fatty acids and organoleptic properties.

1. Herbs, thyme essential oil (EO) and condensed tannin (CT) extracts were compared for their effects, as dietary supplements, on broiler growth performance, nutrient digestibility and volatile fatty acid (VFA) profiles in the gut. Cooked meat from the birds fed on diets with 4 herbs and an EO extract was compared by a taste panel against those fed on the control treatment, for organoleptic properties in the meat. 2. Female broiler chicks were fed on wheat-soybean meal diets from 0-42 d of age. These chicks were given either the basal diet (control), or the basal diet with one of rosemary, garlic or yarrow herbs, mimosa, cranberry or grapeseed CT's, or thyme EO supplements (8 treatments in total). Body weight (BW) and feed consumption (FC) were measured. 3. The garlic supplement tended to improve growth rate over the first 7 d, while mimosa CT and thyme EO supplements reduced weight gains. The mimosa supplement in diets significantly reduced FC to d 21. Meanwhile, the addition of a cranberry supplement reduced the digestibility of DM, OM and N, compared with the controls. Dietary thyme EO, yarrow, rosemary and garlic supplements modified caecal isovaleric and isobutyric acid proportions (presented as 'Other VFA'; p < 0.05). Dietary herb significantly affected the intensity of meat flavour, and the potential of observing both garlic and abnormal flavours. There were large differences between the consumption of red and white meat samples, while meat temperature affected several flavour attributes. 4. Broiler performance and digestibility for birds given dietary garlic and grapeseed CT supplements were similar to the controls, and these supplements appear suitable for dietary inclusion. Careful choices are necessary when selecting dietary plant extract supplements for broilers, but beneficial effects can be observed.

The effects of supplementary bacterial phytase on dietary energy and total tract amino acid digestibility when fed to young chickens.

1. Four diets were offered to broiler chickens from 7 to 17 d of age; these included a phosphorus-adequate positive control (PC) (4·7 g/kg available P), a sub-optimal P negative control (NC, 2·5 g/kg available P) with (500 and 12500 FTU/kg) and without phytase. Dietary apparent metabolisable energy (AME), dietary net energy for production (NEp), the efficiency of AME retention (Kre), heat production and total tract amino acid digestibility coefficients were determined. The determination of NEp involved a comparative slaughter technique in which growing chickens were fed the experimental diets ad libitum. 2. Feed intake, weight gain and feed conversion efficiency increased significantly in a dose dependent manner in response to dietary phytase activity. Overall, the NEp of the phytase supplemented diets significantly improved by approximately 15·6% compared with the negative control, while dietary AME was unaffected. Although phytase did not affect AME, the large increase in the NEp demonstrated that dietary phytases improves energy utilisation, i.e. diverting more energy, not accounted for in the AME procedure, for production. This is largely a result of the stimulatory effect that phytase has on feed intake rather than on digestibility of the diet. 3. Overall, the diet supplemented with 12500 FTU had 6·4% significant improvement in total tract digestibility coefficients of the total amino acids compared with the negative control. With regard to individual amino acids, the impact of phytase was far more pronounced for threonine, an important component of the gastrointestinal mucin, than for other amino acids. 4. Dietary NEp was more highly correlated with performance criteria than dietary AME and seems to be a more sensitive way to evaluate broiler response to phytase supplementation.

The effect of previous exposure to dietary microbial phytase on the endogenous excretions of energy, nitrogen and minerals from turkeys.

1. A precision feeding experiment was conducted with turkeys, which had previously been fed diets with or without phytase, to study the effects on the excretions of endogenous energy (EEL), nitrogen (ENL), amino acids (EAAL) and minerals. 2. Female turkeys (BUT 6) which had been fed one of 4 experimental diets (low P maize-soya diets (control, C), C + 250 international units of phytase/kg diet (FTU), C + 500 FTU and C + 2500 FTU) were used in this study. All birds were fasted and then given 50 mL of glucose solution at 46 d of age. Birds were allocated to individual metabolism cages in a randomised block design with 8 replicates for each of the 4 previously-fed diets. 3. The response of EEL and ENL to phytase pre-exposure was linear. An increase of 100 FTU reduced the EEL and ENL by approximately 1·6 kJ and 20 mg respectively. The results suggest that a minimum activity of phytase of 500 FTU is needed to initiate the reduction of these losses. 4. Pre-exposure to phytase reduced the EAAL, which was best described as a linear response with increasing phytase dose in the pre-study period. An increase of 100 FTU reduced the losses of total endogenous amino acids by approximately 225 mg. 5. In contrast to the results for endogenous energy losses, turkeys pre-exposed to phytase linearly increased their excretions of Ca and Mg with increasing phytase activity in the pre-study period. 6. The effects of feeding turkeys with supplementary phytase continued for at least 4 d after the diets were withdrawn. This suggests that exposure to phytase alters the functionality and secretions of the gastrointestinal tract, which may influence the nutritive value of diets fed immediately after.

Effect of dietary xylanase on energy, amino acid and mineral metabolism, and egg production and quality in laying hens.

1. The aim was to examine the effect of dietary xylanase on the availability of nutrients for laying hens when fed on wheat-rye-soy-based diets. The basal diet was formulated to contain 11.03 MJ/kg apparent metabolisable energy (AME), and the experimental diets were formulated by supplementing the basal diet with four different activities of xylanase (400, 800, 1200 and 1600 xylanase units (XU)/kg). 2. The AME and nitrogen metabolisability coefficients of xylanase-supplemented diets were 1.2% and 7.1%, respectively, greater than in the control diet. 3. Supplementary xylanase significantly improved the coefficients of metabolisability of indispensable, dispensable and total amino acids by 8.2%, 6.9% and 7.8%, respectively, and led to a significantly linear response of total amino acid metabolisability coefficient to xylanase. There was a range of effects within the indispensable amino acids with xylanase supplementation (1600 XU/kg) significantly improving the metabolisability of threonine by 4.9%, but having no have effect on lysine. The response of total amino acid retention to added xylanase was a significant quadratic function and suggests that 800 XU/kg is the optimum supplementary dosage. 4. Supplementary xylanase significantly improved sulphur metabolisability in a linear fashion to a maximum of 2.3% higher than that of the control diet. In terms of daily retention, most of the minerals responded in a quadratic manner to dietary xylanase, as the suggested optimal supplementary level was between 800 and 1200 XU/kg. 5. The yolk colour of the birds receiving 1200 and 1600 XU/kg was 0.33 and 0.28 units (Roche score); these were 4.1% and 3.5%, respectively, darker than the yolk of the birds given the control diet. 6. Birds receiving xylanase had a significantly higher weight gain than those fed on the unsupplemented diet. Feed intake, the number of eggs per hen per d, dirty and cracked eggs, and feed conversion ratio for egg production were not affected by xylanase. These data suggest that use of a xylanase may improve the metabolisability of many nutrients, but that such effects may not always benefit production parameters.

The effect on performance, energy metabolism and hepatic carotenoid content when phytase supplemented diets were fed to broiler chickens.

Two basal diets containing an adequate and a low supply of available P (4.7 vs 2.5 g/kg diet) and three others containing a low available P but supplemented with 250, 500 and 12,500 units of phytase (FTU) per kg diet, respectively, were prepared. Each diet was fed ad libitum to birds in six metabolism cages (five birds in each cage) in a randomised block design. It was found that birds fed a high (12,500 FTU) dosage of phytase grew faster (P<0.001) and retained proportionally more carotenoids in the liver (P<0.05) compared to birds fed unsupplemented diet. The results suggest that dietary phytase may improve the anti-oxidative status of birds fed low P diets through enhancing dietary carotenoid availability.

Effects of different dietary phytase activities on the concentration of antioxidants in the liver of growing broilers.

One-hundred and fifty male chickens were used to evaluate the effects of different activities (0, 250, 500, 12 500 FTU/kg) of phytase on their performance and antioxidant concentration in the liver. The chicks were housed in 30 cages and were allocated to six replicates of five dietary treatments. All diets were formulated to be adequate in energy and protein (12.90 MJ/kg metabolizable energy, 214 g/kg crude protein), however, the negative control (NC) was lower in available P compared with the positive control (PC) (2.5 vs. 4.5 g/kg diet). The other three diets were the NC supplemented with phytase at 250, 500 and 12 500 FTU/kg (NC + 250, NC + 500 and NC + 12 500 FTU respectively). The concentration of antioxidants in the liver of the birds was determined using HPLC at 21 days of age. Low P diets (NC) reduced weight gain, however, supplementation with phytase improved weight gain to the extent that it was better than the PC at the 12 500 FTU treatment (p < 0.05). Feed conversion ratio was also improved by the high level of phytase supplement more than other treatments (p < 0.05). Feed consumption was not affected either by dietary phosphorus concentration or by different phytase supplementation. The antioxidant data showed that the unsupplemented diet with low phosphorus (NC) decreased the concentration of coenzyme Q(10) and retinol-linoleate in the liver compared with that of birds on the adequate phosphorus treatment (PC). Phytase supplementation, especially at the higher doses (500 and 12 500 FTU) increased the level of coenzyme Q(10) to the same level as the PC treatment. In addition, the highest dose (12 500 FTU) of phytase increased retinol concentration in the liver of chickens compared with those on the NC treatment. The highest inclusion level of phytase increased the alpha-tocopherol level in the liver compared with the lower levels of phytase (NC + 250 and NC + 500 FTU).

Previous exposure to dietary phytase reduces the endogenous energy losses from precision-fed chickens.

1. A precision feeding experiment was conducted with broiler chickens, which were previously fed on diets with or without phytase, to study the effects of previous exposure to dietary phytase supplementation on the excretions of endogenous energy, nitrogen, amino acids and minerals. 2. Female Ross 308 broiler chickens, which had previously received one of 4 experimental diets (low P maize/soy diets (control, D), D + 250 international units of phytase per kg diet (FTU), D + 500 FTU and D + 2500 FTU) were used in the study. All birds were starved and then given 50 ml of glucose solution at 44 d of age. The birds were allocated to individual metabolism cages in a randomised block design with 8 replicates of each of the 4 dietary treatments. 3. Chickens which had been previously fed on diets supplemented with phytase excreted 32% less energy and 28% less dry matter per kg metabolic body weight (W(075)) from endogenous sources, compared to birds fed the unsupplemented diet. 4. Birds previously given phytase supplemented diets excreted 60% less sodium than those given the control diet, but there was no effect on all other minerals investigated. There was no effect of diet on the excretion of endogenous N, sialic acid or amino acids. 5. The results showed that the effects of feeding chickens on diets with supplementary phytase may continue for a few days after the diets are withdrawn. This suggests that previous exposure to phytase may alter the nutritive value of follow-on diets, which may be a commercially important effect.

Influence of tannic acid and polyethylene glycol on the excretion and digestibility of amino acids in gelatin-fed broilers.

1. A precision feeding experiment was conducted to evaluate the effects of tannic acid (TA) and polyethylene glycol (PEG) on the excretion of amino acids, and the apparent and true digestibility of gelatin protein in broilers. 2. In a 3 x 2 x 2 factorial design, ninety-six 7-week-old broiler cockerels in 8 replicates of 12 treatments, were fed on warm solution of gelatin alone (0, 6 or 12 g/50 ml/bird, Treatments 1-3), or gelatin with TA solution (4.5 g TA/10 ml/bird, Treatments 4-6) and PEG solution (2 g/10 ml/bird, Treatments 7-12). Total excreta were collected for 48 h and the amino acid contents of gelatin and excreta were determined. 3. In the absence of TA, the digestibility of gelatin was almost complete. TA increased the excretion of amino acids from gelatin-fed birds to varying extents. Although the digestibility of all indispensable and dispensable amino acids was adversely affected by the presence of TA, increasing the amount of gelatin from 6 to 12 g improved the apparent and true digestibility of amino acids. PEG reduced the excretion of amino acids and improved the digestibility of amino acids in gelatin in TA-dosed birds. However, the effect was greater when the lesser amount of gelatin was fed. 4. In conclusion, PEG seemed to play an important role in reducing the effect of dietary tannins in the gastrointestinal tract of birds fed on diets high in tannins and improved protein digestibility and utilisation, particularly when the diet was low or marginal in protein.

Effects of dietary phytase on performance and nutrient metabolism in chickens.

1. A broiler growth study was conducted to compare the effect of different concentrations of an Escherichia coli-derived phytase on performance, apparent metabolisable energy (AME), nitrogen (N), amino acid and mineral metabolisability, sialic acid excretion and villus morphology when fed to broiler chickens. 2. Female Ross 308 broilers (480) were reared in floor pens from 0 to 28 d of age. All birds were fed on nutritionally complete starter (0 to 21 d of age) and grower diets (21 to 28 d of age) with the exception that they were low in P (28 and 23 g/kg available P, respectively). These maize-soy diets were supplemented with 0, 250, 500 or 2500 phytase units (FTU)/kg feed. 3. Between 21 and 28 d of age, two birds from each floor pen were selected, and each pair placed in one of 32 metabolism cages (two birds per cage). Feed intake was recorded and excreta collected for the last 2 d of the feeding period, and AME, N, amino acid and mineral metabolisability coefficients and endogenous losses were determined following a total collection procedure. 4. Feed intake and weight gain increased in a linear manner in response to phytase dose, with an average increase of approximately 11.7 and 13.5%, respectively, compared with chickens fed on the low-P diet. Birds given diets with 2500 FTU weighed 6.6% more and had a 2.4% higher feed conversion efficiency (FCE) than those fed on diets containing 500 FTU. 5. Enzyme supplementation increased the intake of AME and metabolisable N by 10.3 and 3.9%, respectively, principally through increases in feed intake. Birds given enzyme-supplemented diets also improved their intake of metabolisable amino acids and P by approximately 14 and 12.4%, respectively, compared with birds fed on the control diet. Enzyme supplementation did not affect ileal villus morphometry of the birds.

The effect of organic diets on the performance of pullets maintained under semi-organic conditions.

The effects of organic diets, with or without supplements of betaine, saponin, fructo-oligosaccharide and methionine, on the health, performance and gut flora of pullets were investigated. A comparison was also made between birds fed organic diets and those fed a non-organic diet. Day-old Lohmann Tradition pullets were reared in 24 groups of 64 chicks indoors until 11 weeks, and then in 48 groups of 24 to 27 chicks with access to range until 17 weeks of age. Groups of birds were fed one of eight diets, a conventional rearing diet with supplementary amino acids, an organic basal diet, organic basal plus methionine and organic basal supplemented with one of the test ingredients. At most stages of growth the birds fed the conventional diet and those fed the basal diet with methionine performed better than those that had no supplemental methionine. Other dietary treatments had no consistently significant effect on growth, the microbial populations within the gastro-intestinal tract of the birds or the number of parasite eggs excreted. After 5 weeks with access to range, the birds that were fed three out of five diets regarded as deficient in sulphur amino acids achieved similar weights (P > 0.05) to birds that received diets adequate in sulphur amino acids. Health and welfare of birds fed organic diets was not adversely affected; however, an investigation of birds housed in larger flocks and taken into the laying phase, when physical demands on birds are greatest, is required.

The effect of herbs and their associated essential oils on performance, dietary digestibility and gut microflora in chickens from 7 to 28 days of age.

1. The effect of the dietary inclusion of 5 culinary herbs or their essential oils on the growth, digestibility and intestinal microflora status in female broiler chicks was assessed. From 7 to 28 d of age, either a basal control diet without supplement was given or one of 10 others, consisting of the basal diet with either 10 g/kg herb (thyme, oregano, marjoram, rosemary or yarrow) or 1 g/kg of essential oil. 2. Body mass (BM) and feed consumption (AFC) were measured on a weekly basis and used to calculate chick performance. Total viable counts of lactic acid bacteria, coliforms, anaerobes and Clostridium perfringens were determined at 25 d. Apparent nutrient digestibilities were calculated from the measured values for gross energy, nitrogen (N), dry matter (DM) and organic matter, and sialic acid concentration was also measured. 3. Generally, dietary thyme oil or yarrow herb inclusion had the most positive effects on chick performance, while oregano herb and yarrow oil were the poorest supplements. Only thyme and yarrow in these diets had a different effect when used as a herb or oil on weight gain and BM. 4. Dietary treatment had no effect on the intestinal microflora populations, apparent metabolisable energy (AME) or the calculated coefficients of digestibility. Sialic acid concentration was greatest in the birds given dietary thyme oil, compared with all other treatments except those birds receiving marjoram oil, rosemary herb and the controls. However, less sialic acid was excreted in those birds given diets with oregano or rosemary oils, or oregano herb, than in the controls. 5. Plant extracts in diets may therefore affect chick performance, gut health and endogenous secretions, although the chemical composition of the extract appears to be important in obtaining the optimal effects.

Energy metabolisability and digestibility of amino acids by broilers fed on malted sorghum sprouts supplemented with polyethylene glycol, charcoal, phytase and xylanase.

1. A precision feeding study was conducted to determine the metabolisable energy and amino acid digestibility in broilers fed on malted sorghum sprouts (MSP) supplemented with polyethylene glycol (PEG), charcoal (CH), phytase and xylanase. 2. A total of 64 male Ross broilers housed individually (8 replicates per treatment) were fed 30 g of the feedstuff as follows by gavage: MSP, MSP+1 g PEG/kg, MSP+10 g PEG/kg, MSP+1 g CH/kg, MSP+10 g CH/kg, MSP+3600 IU of evolved E. coli phytase/kg (EC 3.1.3.26) and MSP+1600 IU of bacterial xylanase/kg (EC 3.2.1.8). Another group of birds was used for the assessment of endogenous loss and they were provided with 50 ml glucose solution each by gavage. 3. True dry matter digestibility (TDMD), true nitrogen retention (TNR), total tract digestibility of apparent and true metabolisable energy (AME and TME) and amino acid (AAD and TAAD) were determined. 4. MSP contained 244.4, 24.0, 74.9 and 224.0 g/kg of crude protein, ether extract, ash and neutral detergent fibre, respectively. The total tannin content of the product was 140 g/kg and 99% of this was bound. 5. The various dietary treatments did not significantly affect the TDMD, TNR, AME and TME of MSP. The low values (0.471 g/g, -0.164 g/g, 6.15 MJ/kg and 9.31 MJ/kg, respectively) for the above measurements depicted the low feeding value of un-supplemented MSP for poultry. Also, PEG, CH and enzymes did not improve the AAD and TAAD of MSP for poultry. 6. It was concluded that the tannin content of MSP is high and it appeared to be bound with other nutrients thereby reducing their availability. This may explain its low AME and amino acid digestibility and the lack of effect of the various treatments for poultry.

Diets containing Escherichia coli-derived phytase on young chickens and turkeys: effects on performance, metabolizable energy, endogenous secretions, and intestinal morphology.

The aim of this experiment was to compare the responses of young broiler chickens directly with the responses of turkeys to different dietary phytase concentrations. Nine hundred sixty birds (480 female Ross 308 broilers, and 480 female BUT6 turkeys) were reared in 64 floor pens from 0 to 21 d of age. Each species was fed a nutritionally complete (12.79 MJ/kg of AME, 231 g/kg of CP vs. 11.75 MJ/kg of AME, 285 g/kg of CP for chickens and turkeys, respectively), low-P (28 and 37 g/kg available P for chickens and turkeys, respectively) corn (maize)-soy feed supplemented with either 0, 250, 500, or 2,500 phytase units (phytase/kg of feed) to give a total of 4 diets per species. The study was conducted in a split-plot design and each dietary treatment was replicated 8 times. Performance, AME, sialic acid (SA) excretions, and ileal villus morphology of 21-d-old broiler chickens and turkeys were determined. Overall, chickens grew faster and consumed more than turkeys throughout the study period. Dietary enzyme concentrations linearly increased the feed intake and weight gain of birds. The results were improved, on average, as follows: feed intake by 11.2 and 6.5%, gain by 10.2 and 13.2%, feed efficiency by 0 and 7.6%, AME by 1.4 and 5.7%, and AME intake by 13.1 and 9.8% for chickens and turkeys, respectively. The AME data were subject to a species x phytase interaction, whereby increasing the phytase dosage led to significant increments in parameters for turkeys but not broilers; broilers recovered significantly more energy from the ration than did turkeys. A quadratic relationship existed between dietary AME and phytase concentrations. Turkeys excreted more SA than did chickens in the absence of phytase, whereas supplementation with phytase (250 and 500 phytase units) reduced the excretion of SA in turkeys. Enzyme supplementation did not affect the ileal villus morphometry of the 2 species. We concluded that both species can tolerate phytase concentrations much higher than 1,000 phytase units and that these concentrations have further beneficial effects compared with lower phytase concentrations. The work reported here supports the hypothesis that supplementing turkey diets with phytase will need to be considered independently of chicken diets, considering the components in the diets, such that optimal responses can be obtained.

Effects of carotenoids from lucerne, marigold and tomato on egg yolk pigmentation and carotenoid composition.

1. The effects of various sources of natural carotenoids (Px alfalfa concentrate, tomato powder and marigold extract) as feed additives in quail diets on egg yolk pigmentation and carotenoid composition were investigated. 2. Adult Japanese quail were fed one of 5 different diets for 23 d: three diets each contained Px alfalfa concentrate (PX) or tomato powder (TP) or marigold extract (MG), one diet contained marigold extract and tomato powder (MG + TP) and a control diet (wheat/barley based) was low in carotenoid. All products were added at a rate of 2%, apart from marigold extract which was added at a rate of 0.2%. 3. Visual assessment of yolk colour (Roche colour fan) showed a stabilised yolk colour of 1.6, 7.7, 8.5, 8.8 and 10.6 for the control, PX, TP, MG and MG + TP treatments, respectively. 4. The total carotenoid concentration of the egg yolks were 2.2, 22.4, 4.1, 39.0 and 37.7 microg/g for the experimental groups fed the following diets: control, PX, TP, MG and MG + TP, respectively. Deposition of retinol, alpha-tocopherol and gamma-tocopherol in the egg yolk was unaffected by treatments. 5. Lutein was shown to be the major carotenoid in the egg yolk, comprising 1.65, 17.97, 2.03, 31.14 and 28.57 microg/g in control, PX, TP, MG and MG + TP, respectively. Inclusion of TP in the quail diet resulted in lycopene transfer to the egg. 6. It was concluded that, in comparison with the control group, there was an increase in the yolk concentrations of lutein, zeaxanthin, lycopene and beta-carotene in eggs produced by female quail fed diets supplemented with natural carotenoids.

Effects of supplementing broiler breeder diets with organoselenium compounds and polyunsaturated fatty acids on hatchability.

The effects of supplementing broiler breeder diets with polyunsaturated fatty acids (PUFA) and organoselenium compounds on fertility, hatchability, and the weight of 1-d-old chicks was assessed. Prepeak (23 wk) and peak (27 wk) production breeders were fed 1 of 4 diets: a wheat-based commercial breeder diet with 55 g/kg of either soybean oil (SO) or fish oil (FO), but no added Se (only that originating from feed ingredients), and each diet with added Se as Sel-Plex (SO + Se, FO + Se). The diets were designed to contain <0.1 mg/kg of Se and about 0.5 mg/kg of Se for the nonsupplemented (no added Se) and the supplemented diets, respectively. The Se concentration of the eggshell of the hatching egg was measured. The concentration of Se, PUFA, and total lipid content of the brain and liver of the 1-d-old chick was determined. The number of fertile eggs increased, embryonic mortality decreased, and hatchability increased as hen age increased from 23 to 27 wk. The Se concentration in the eggshell and the brain and liver of 1-d-old chicks was higher in the high-Se treatments com pared with the concentration in the low-Se treatments. Fish oil inclusion in the breeder diet increased embryonic mortality in wk 3 of incubation and reduced both hatchability and 1-d-old chick weight in hens of both ages. The addition of Se to the FO diets ameliorated some of these adverse effects, because chicks hatched from eggs laid by 23-wk-old breeders of the FO + Se treatment were heavier than those receiving the FO treatment. The Se concentration in the brain and liver of chicks from the FO hens was higher than that in chicks from the SO hens. The concentration of docosahexaenoic fatty acid was higher in the liver of chicks from the SO + Se treatment compared with that of chicks from the SO treatment, indicating possible protective effects of Se. Hatchability was decreased by increased PUFA and was higher in 27-wk-old compared with 23-wk-old breeders.

Maternal organo-selenium compounds and polyunsaturated fatty acids affect progeny performance and levels of selenium and docosahexaenoic acid in the chick tissues.

The effects of supplementing broiler breeder diets with polyunsaturated fatty acids (PUFA) and organo-Se compounds on the levels of Se and PUFA in chick tissues and on chick performance were assessed. Prepeak (23 wk) and peak (27 wk) production broiler breeders were fed 1 of 4 diets: a wheat-based commercial diet with soybean oil or fish oil but no added Se, and each diet with added Se as Sel-Plex (soybean oil + Se, fish oil + Se; Alltech Inc, Nicholasville, KY). The diets were designed to contain less than 0.1 mg of Se/kg and about 0.5 mg/kg for the nonsupplemented and the supplemented diets, respectively. As-hatched chicks from the 4 parental treatments were fed a nutritionally high quality diet (ME = 12.57 MJ/kg; CP = 228.7 g/kg) or a low quality diet (ME = 10.28 MJ/kg; CP = 182.8 g/kg), resulting in 8 dietary treatments. Performance was better and mortality lower in chicks from 27-wk-old breeders compared with those from 23-wk-old breeders. Fish oil in the maternal diet increased progeny mortality and reduced chick body mass at hatch. Body mass at 7 and 14 d posthatch was lower in chicks fed the low quality diet compared with chicks fed the high quality diet. At hatch, and for up to 14 d posthatch, chicks from hens fed diets high in PUFA had higher concentrations of docosahexaenoic acid (DHA) in the brain and liver compared with chicks hatched from hens fed diets low in PUFA. The DHA content of the tissues of chicks from breeders fed diets supplemented with Se was higher than that in chicks from breeders fed unsupplemented diets. Even after 14 d of being fed a diet with identical levels of Se, chicks hatched from parents fed diets high in Se had higher tissue Se concentrations than those hatched from parents fed diets low in Se. Supplementation of the maternal diet of chicks with organo-Se appears to enhance the DHA concentration of the chick brain, which may improve brain function.

Supplementation of corn-soy-based diets with an Eschericia coli-derived phytase: effects on broiler chick performance and the digestibility of amino acids and metabolizability of minerals and energy.

The effect of the supplementation of diets containing low available P concentrations with low and supra-activities of an Eschericia coli 6-phytase was assessed using growing broiler chicks. A total of 384 female Ross broiler chicks were weighed at d 1 of life and assigned to 1 of 8 experimental treatments. There were 12 replicate cages with 4 chicks per cage, and the diets were fed from d 1 of life for a period of 16 d. A positive control diet (5 g/kg of available P) and a negative control diet (3 g/kg of available P) were used, and 6 more diets were manufactured by supplementing the negative control diet with 150, 300, 600, 1,200, 2,400, and 24,000 U/kg of exogenous phytase. Body weight gain and feed conversion ratios were determined, as were nutrient digestibility coefficients and toe ash values. Birds fed the negative control diet had lower (P < 0.05) weight gains than those fed the positive control diet. The addition of exogenous phytase above 150 U/kg improved (P < 0.05) weight gain, toe ash percentage, and nutrient utilization of the birds fed the negative control diet. Furthermore, the 24,000 U/kg of diet improved (P < 0.05) toe ash percentage and the utilization of several nutrients beyond that of the lower doses of phytase. It can be concluded that the supplementation of diets containing 3 g/kg of available P with exogenous phytase can improve the performance of chicks to that of birds fed a diet containing 5 g/kg of available P. In addition, the use of high doses of phytase (> 1,000 U/kg of diet) can improve nutrient availability in poultry diets beyond that of diets containing lower (< 1,000 U/kg) phytase activities. These results may be mediated partially by reduced endogenous loss as well as an increase in the availability of dietary nutrients as indicated by improvements in digestibility coefficients.

Phytic acid and phytase: implications for protein utilization by poultry.

The effect of the ingestion of myo-inositol hexaphosphate (IP6) and phytase (EC 3.1.3.26) on the digestibility of casein was investigated using growing broiler chickens. A total of 64 female Ross broilers were used in a precision feeding study. One group of 8 birds was fed a solution of glucose to estimate endogenous losses. Seven groups, each of 8 birds, were fed either casein, casein + 1,000 units of phytase activity (FTU), casein + 2,000 FTU, casein + 0.5 g of IP6, casein + 0.5 g of IP6 + 1,000 FTU, casein + 1 g of IP6, or casein + 1 g of IP6 + 1,000 FTU. The excretion of DM, amino acids, nitrogen, minerals, and phytate-phosphorus was determined over a 48-h period and nutrient digestibility coefficients were calculated. Casein was found to be highly digestible, with true coefficients of DM, N, and amino acid digestibility of between 0.85 and 1.0. However, the ingestion of IP6 reduced (P < 0.05) the digestibility coefficients of amino acids, N, and DM of casein compared with birds fed casein alone. Supplementation of the mixture of casein and IP6 with phytase improved (P < 0.05) the digestibility coefficients of amino acids compared with birds fed on casein and IP6 with no supplemental phytase. The excretion of endogenous minerals was increased (P < 0.05) by the ingestion of IP6 and reduced (P < 0.05) by the supplementation of IP6 with phytase. In the absence of exogenous phytase, the recovery of phytate-P in excreta was approximately 80%. However, the recovery of phytate-P was significantly reduced by the addition of exogenous phytase to the IP6/casein mixture. It can be concluded that the ingestion of IP6 reduces the digestibility coefficients of amino acids and the metabolizability of nitrogen of casein. This is likely to be mediated partially through increased endogenous losses. However, the addition of phytase can partially ameliorate the detrimental effects of IP6 on protein utilization.