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Articles by P.W. Waldroup
Total Records ( 22 ) for P.W. Waldroup
  E.A. Saleh , S.E. Watkins , A.L. Waldroup and P.W. Waldroup
  Two trials of identical design were conducted in floor pens to characterize the response of male broilers grown to heavy weights for further processing to dietary nutrient density levels. Nutrient density is defined as the metabolizable energy content of the diet with all essential nutrients maintained in proportion. Ten treatments were utilized with varying nutrient densities obtained by adding poultry oil from 0 to 9% in increments of 1%. Crude protein, amino acids, and other essential nutrients were maintained in proportion to dietary energy levels. Body weights, feed consumed and processing quality were obtained at different intervals up to 63 days of age. Body weight peaked with the diet containing 6% added fat (3267 ME Kcal/ kg, mean of starter, grower, and finisher ME values). Feed intake tended to decrease with increasing nutrient density, but not at a rate commensurate with the change in energy levels. Feed conversion (g gain per g feed) improved as dietary nutrient density increased. Dressing percentage tended to decrease as dietary nutrient density level increased. Abdominal fat and breast meat, both on an absolute weight or percentage of carcass weight basis, remained rather constant when protein was maintained in proportion to energy.
  E.A. Saleh , S.E. Watkins , A.L. Waldroup and P.W. Waldroup
  Three trials with identical experimental design were conducted to examine the effects of dietary nutrient density and energy feeding programs on male broiler chickens grown to heavy weights for further processing. Diets were formulated to provide a minimum of 107.5% of NRC (1994) amino acid requirements, maintained in proportion to dietary energy levels. Diets with different nutrient density were obtained by adding 0, 3, and 6% poultry oil (PO) while maintaining essential nutrients in a constant balance with energy. Diets within each age period (0 to 21 days, 21 to 42 days, and 42 to 63 days) had similar ratios of metabolizable energy to crude protein. Six feeding programs were obtained by either feeding these three levels of PO continuously to 63 d or by increasing the amount of PO in the diet at 21 d. Live performance was examined at 14, 21, 42, and 63 d and carcass composition was examined at 63 d. Dietary energy levels or feeding programs had no significant effect on body weight except at 42 d, which improved as PO was added to the diet. Feed intake was not significantly affected by feeding various levels of poultry oil or by utilizing different feeding programs. However, feed conversion at all ages showed a significant improvement as the level of supplemental PO increased. Calorie conversion was not affected at 14, 21, and 42 d. At 63 d, calorie conversion was significantly reduced when birds received diets with increased supplemental PO. Neither supplemental PO or feeding program affected the dressing percentage or yield of economically important carcass components at 63 d when examined on an absolute basis or as percentage of carcass weight. Abdominal fat content was not significantly influenced by level of supplemental poultry oil.
  Jianlin Si , D.J. Burnham and P.W. Waldroup
  This study was conducted to explore the extent to which CP can be reduced in corn-soybean meal broiler starter diets by amino acid supplementation while maintaining adequate performance. Using corn and soybean meal of known composition, diets were formulated by linear programming using a minimum of 107.5% of NRC (1994) amino acid recommendations. No minimum CP was required; as each amino acid became limiting crystalline sources were provided to meet the minimum specification. In sequence these were Met, Thr, Lys, Val, Ile, Arg, Phe, and Trp, resulting in eight treatments ranging from 16.61 to 22.48% CP. All diets contained 0.3% sodium bicarbonate and 0.2% aluminum hydroxide as a buffer and antacid. Three additional treatments utilized potassium sulfate to maintain a minimum dietary electrolyte balance (Na + K - Cl) of 250 meq/kg. Each treatment was fed to twelve replicate groups of six male broiler chicks from 1 to 21 d. Reducing CP below 20% while providing indispensable amino acids resulted in a significant reduction in body weight (BW) and feed conversion ratio (FCR). Crude protein content of freeze-dried carcasses declined and fat content increased as diet CP decreased. Feather content (actual weight or % of BW) was not affected until the CP was reduced to less than 18%. Maintaining dietary electrolyte balance at 250 meq/kg in reduced CP diets had no significant effect on any parameter.
  Jianlin Si , J.H. Kersey , C.A. Fritts and P.W. Waldroup
  Levels of lysine (Lys) and methionine (Met) in excess of NRC recommendations may result in enhanced performance, especially in regard to breast meat yield (BMY). Some people have interpreted the "ideal Protein" concept to suggest that amino acids such as Met should be kept in an "Ideal" ratio with Lys even though Lys may be in excess of actual needs. The objectives of this study were twofold: 1) to evaluate the effects of levels of Lys and Met in excess of NRC recommendations in diets of male broilers grown for further processing; 2) to determine if any interaction exists between levels of Lys and Met when minimum levels are exceeded. Three studies of identical design were conducted. Corn, soybean meal and corn gluten meal of known composition were used to formulate basal diets for 0 to 3, 3 to 6, and 6 to 9 wk which provided a minimum of 110% of NRC (1994) amino acid recommendations other than Lys, Met and TSAA which were at 100% of recommended levels. From the base diets, experimental diets were derived by additions of lysine HCl and DL methionine to provide a factorial arrangement with three levels of Lys (NRC, NRC + 0.15%, NRC + 0.3%) and four levels of Met and TSAA (NRC, NRC + 0.05%, NRC + 0.1%, NRC + 0.15%). Each of the 12 diets was fed to two (trial 1) or four (trial 2 and 3) replicate pens of 50 male broilers (Cobb 500). Birds were weighed and feed consumption determined at 3, 6, 7, 8, and 9 week. Samples of birds were processed at 7, 8, 9 wk for parts yield. Although significant differences in performance were noted among trials due to environmental temperature there was no trial x treatment interaction so data were combined. There were no significant interactions between Lys and Met for any parameter when both were fed equal to or in excess of NRC recommendations. Increasing Lys above NRC recommendations significantly improved BW and FCR at 21 d but not at later ages; BMY was improved by increasing Lys only at 63 d. Increasing Met above NRC significantly improved FCR at 42 and 56d; there was no significant effect of Met levels on BMY at any age. Results of this study suggest that people formulating diet on "Ideal Protein" basis should not elevate the level of Met if lysine is in excess of its minimum needs.
  E.A. Saleh , S.E. Watkins , A.L. Waldroup and P.W. Waldroup
  Six feeding programs for broilers based on level and time of feeding poultry oil (PO) were compared as well as early feed restriction. All diets were formulated to contain a minimum of 107.5% of NRC (1994) amino acid recommendations, maintained in proportion to dietary energy level. Three different energy levels within each age period were obtained by adding 0, 3, and 6% PO and formulating for optimum nutrient density. Diets within each age period (starter, 0 to 21 days; grower, 21 to 42 days; and finisher, 42 to 84 days) had similar calorie:protein ratios. During the restriction period of 7 to 14 d, the birds were given an amount of their respective diets calculated to provide daily maintenance energy requirements. Before and after the restriction period, the birds were offered feed for ad libitum consumption. Body weight, feed consumption, and processing quality were obtained at 63, 70, 77, and 84 d of age. In general, body weight and feed conversion were improved as PO was added to the diet; however, the response was not always significant. Mortality, dressing percentage, abdominal fat, breast, leg, and wing yield did not differ significantly as various levels of PO were fed. In the few instances where there was a significant difference, it did not follow any specific trend among the dietary treatments. There was a significant decrease in the ability to utilize energy by birds grown to 63, 70, 77, or 84 d as the level of PO increased. Feed restriction reduced body weight at 63, 70, and 77 d of age. However, feed conversion was significantly improved and mortality significantly reduced at all ages as compared to birds fed ad libitum. Feed restriction had little impact on abdominal fat. No interaction was observed between PO levels and feed restriction.
  Q. Jiang , P.W. Waldroup and C.A. Fritts
  Reduction of the dietary crude protein (CP) by amino acid supplementation is effective to a point but performance eventually declines. This study was conducted to determine if supplementation with certain amino acids that serve as precursors to metabolites involved in the urea cycle or the formation of essential amino acids might improve the performance at low protein levels. Diets were formulated to meet 100% or 110% of NRC recommendations for essential amino acids with Lys at 110% or 120% of recommendations. The CP levels were 16, 18, 20, 22 or 24%. The CP and ME equivalency values of amino acids were considered in the formulation. A minimum dietary electrolyte balance [(Na+K)-Cl)] of 200 meq/kg was maintained. Amino acids added to the low CP diets included: 1) Gly; 2) Gly + Arg; 3) Gly + Pro; 4) Arg + Pro; 5) Gly + Arg + Pro; 6) Gly + Arg + Pro + Glu. The Gly, Arg, and Pro were added at 0.2% while Glu was added at 0.4%. Each dietary treatment was fed to six pens of five male chicks from 1 to 21 d. Feeding diets with less than 22% CP resulted in loss in the body weight (BW) and impaired the feed conversion ratio (FCR) regardless of the amino acid status. Supplementation of low CP diets with Gly significantly improved the performance of broilers but did not reach that obtained on diets with 22 or 24% CP. None of the other amino acid supplements consistently influenced the performance of chicks in the absence of Gly. These data suggest that Gly may be a limiting factor in diets low in CP. It is likely that some of the requirements for lesser researched essential amino acids may be insufficient to support performance at lower levels of crude protein.
  P.W. Waldroup and A.L. Waldroup
  Studies were conducted to determine the influence of the fatty acid composition of the dietary fat supplement on the fatty acid composition of the adipose tissue of broilers. Samples of lard, tallow, poultry oil, and soybean oil, representative of the major source of fats and oils in poultry diets in the United States, were blended in various combinations and fed at 6.34% of the diet in corn-soybean meal broiler finisher diets fed 35 to 56 d of age. Samples of adipose tissue were subjected to fatty acid analysis and regression analysis was used to develop equations for predicting carcass fatty acid composition from the composition of the dietary fat supplement. Highly significant R2 values were observed, indicating that these equations can be used to predict the influence that a particular blend of dietary fatty acids will have upon changes in the fatty acid composition of the adipose tissue of broilers fed diets supplemented with these fats. If sources with markedly different fatty acid structures such as coconut oil, linseed oil, or fish oil are used in constructing the fat blends, these equations may not be applicable.
  P.W. Waldroup , Q. Jiang and C.A. Fritts
  A study was conducted to evaluate effects of dietary crude protein (CP) level and Gly and Thr supplementation on performance of male broiler chicks during the period of 0 to 21 days. Diets were formulated based on NRC (1994) recommendations (Lysine at 110% of suggested level). All diets were formulated to contain 3,200 ME kcal/kg. A minimum dietary electrolyte balance of 250 meq/kg was stipulated with a minimum of 0.25% sodium and 0.20% chloride. Five primary diets were formulated to contain 16%, 18%, 20%, 22%, and 24% CP. The diets were then supplemented with additional 0, 0.2%, 0.4% Gly or 0, 0.2%, 0.4% Thr in all possible combinations resulting in a 5x3x3 factorial arrangement. Each of the 45 treatments was fed to six replicate pens of five male commercial broilers. The test diets and tap water were provided for the ad libitum consumption from 1 to 21 d of age. At 21 d of age body weight and feed consumption were determined. Reducing dietary protein below 22% significantly reduced 21 d BW and depressed feed conversion. Addition of 0.2 or 0.4% Gly significantly improved BW and numerically improved feed conversion at lower levels of protein but at protein levels of 20% or more the basal diets appeared to provide sufficient Gly. These data suggest that requirements for Gly suggested by NRC (1994) are inadequate in diets with low CP. Thr supplementation was ineffective in improving performance at low CP levels suggesting that the present recommendations of NRC (1994) are adequate. Mortality did not vary significantly among chicks receiving all experimental diets.
  P.W. Waldroup , Q. Jiang and C.A. Fritts
  Reduction of dietary crude protein (CP) with amino acid supplementation has been effective in reducing the cost of poultry feed. However, the performance of broilers declines when CP levels reaches a point and can not be totally restored with amino acid supplementation. This study was conducted to determine if differences in feed intake were responsible for the reduced performance at low protein levels. Diets were formulated to meet 100% of NRC (1994) recommendations for indispensable amino acids (Lys at 110%) with CP levels of 16%, 18%, 20%, 22% or 24% with the CP and metabolic energy (ME) equivalency values of amino acids considered in the diet formulation. A minimum dietary electrolyte balance of 200 meq/kg was maintained. There were two feeding regimes including ad libitum feeding and control feeding with a total of ten treatments. All birds were provided a complete 24% CP diet ad libitum from one to 7 d. At 7 d chicks were weighed and placed on test diets containing the various levels of CP. One group remained on ad libitum feeding while the other group was control fed. Feeding diets with less than 20% CP resulted in the loss of BW and impaired feed conversion ratio (FCR) regardless of feeding regimes. There was no significant difference in feed intake and mortality among different dietary treatments in both feeding regimes. Reduction in feed intake does not appear to be the cause of reduced performance on diets low in CP.
  P.W. Waldroup , S.E. Watkins and H.M. Hellwig
  Hens of a commercial strain of SCWL hens were subjected to a molt and allowed to resume production before being placed on test diets consisting of a nutritionally complete basal diet supplemented with three sources of sodium (sodium chloride, sodium bicarbonate, and sodium sulfate) at three levels of added sodium (0.10, 0.20, 0.30%) with three levels of nonphytate phosphorus (0.25, 0.45, and 0.65%) in a complete factorial arrangement. When non-chloride sources of sodium were used the diet was supplemented with 0.12% Cl from calcium chloride. A reference group of hens within each level of nonphytate phosphorus was fed a diet with no supplemental sodium or chloride. Each of the thirty resulting dietary treatments was assigned to eight groups of hens, with a replicate group consisting of five 30.5 x 45.7 cm cages with one hen per cage fed from a common feed container. After allowing the hens to acclimate to the test diets for 28 d data were collected for a second 28 d period on rate of egg production, feed intake, egg weight, shell breaking force, and shell deformation time. Results of the study indicate that no more than 266 mg/d of nonphytate P was adequate for egg production. Increasing the dietary P level greater than 0.45% nonphytate P resulted in a significant reduction in egg shell strength. A dietary sodium intake of 128 mg/d appeared adequate to support optimum performance. Use of sodium bicarbonate or sodium sulfate in place of sodium chloride appeared to have no benefits in regard to egg shell strength in this study.
  P.W. Waldroup , Q. Jiang and C.A. Fritts
  A study was conducted to evaluate the effects of adding all essential amino acids (EAA) equal to that of higher CP diets or a mixture of nonessential amino acids (NEAA) to low CP diets on the live performance of broilers during the period of 0 to 21 d. A series of experimental diets comprised primarily of corn and soybean meal were formulated to contain 3,200 ME kcal/kg. Five primary diets were formulated to contain 16, 18, 20, 22, and 24% CP. Requirement levels for EAA (110% of NRC, 1994) were accomplished when necessary by adding crystalline amino acids. In each of these dietary series, diets with 16, 18, and 20% CP were supplemented with additional EAA (Trp, Ile, His, Val, Leu, Arg, Gly and Phe) to bring the content of all these EAA to a level equal to that of the 22% CP diet. Additional diets in each series with 16, 18, and 20% CP were supplemented with a mixture of NEAA (equal parts of Ala, Glu, and Glu-NH2) to provide levels of nitrogen equivalent to that provided by the EAA supplementation in the previous diets. Each of the treatments was fed to 12 replicate pens of 5 male chicks of a commercial broiler strain. The reduction of CP level in the starter diets had a significant influence on the live performance. Decreasing CP levels lower than 22% significantly decreased BW gain and increased the feed conversion ratio (FCR). Adding the EAA or NEAA mixtures to the low CP diets significantly improved the performance but did not completely overcome the adverse effects of the low CP diets.
  P.W. Waldroup and C.A. Fritts
  A study was conducted to evaluate the effects of supplementation of corn-soybean meal based diets with betaine and choline on live performance and breast meat yield of male broiler chicks. Diets formulated to meet nutrient levels of top broiler companies were supplemented with either 0 or 1000 mg/kg betaine in combination with either 0 or 1000 mg/kg choline. Betaine supplementation was carried out either for the full 49 d feeding trial or initiated at 35 d of age. Each dietary treatment was assigned to eight replicate pens of 60 male chicks of a commercial strain. At 42 and 49 d of age samples of birds were processed under commercial conditions and dressing percentage and breast yield determined. The results of this study indicate little or no positive benefit in terms of body weight gain, feed conversion, or mortality from the addition of betaine to nutritionally adequate corn-soybean meal based diets for broiler chicks in situations where disease challenge from coccidiosis is not a major issue. Improvements in dressing percentage were obtained from betaine supplementation and in breast yield from choline supplementation at 42 d of age but not at 49 d of age. Therefore, age of bird might be a consideration for using these supplements as birds processed at younger ages might be more responsive to these nutrients. Further studies are needed to evaluate the potential effect of age on response to choline and betaine.
  K.Y. Zhang , F. Yan , C.A. Keen and P.W. Waldroup
  Two experiments were conducted to evaluate the use of two products containing essential oils in diets for broiler chickens. These products were RepaXol™, a mixture of essential oils (including oregano, cinnamon, thyme, and capsicum), and Avigro™, a mixture of essential oils along with organic acids (fumaric, citric, and malic). In the first experiment, conducted in litter-floor pens, eight replicate pens of 37 male and 37 female chicks of a commercial strain were fed a non-medicated corn-soybean diet, a diet containing antibiotics (bacitracin methylene disalicylate in starter and grower and virginamycin in finisher), a diet containing 0.5 kg/ton of Avigro™, and three additional treatments utilizing RepaXol™ at 100 g/ton continuously, 00 g/ton for 0-14 d, 75 g/ton for 14-35 d; 50 g/ton for 35 to 42 d, or 150 g/ton for 0-14 d, 100 g/ton for 14-35 d; 75 g/ton for 35 to 42d. All diets were in pelleted form with starter diets crumbled. Birds were grown to 42 d. In the second experiment, eight replicate pens of five male birds housed in battery brooders were fed the negative control diet with no additives, the negative control diet with 0.5 or 1.0 kg/ton of Avigro™, or diets with RepaXol™ at 100, 200, or 300 g/ton. Diets were fed as mash. Results from the first experiment indicated no positive improvements in body weight, feed consumption, mortality, or carcass yield from addition of Avigro™ or RepaXol™. Birds fed RepaXol™ at 150 g/ton had improved feed conversion at 14 d but not over the course of the experiment. Addition of the antibiotics to the diet also had no positive improvement in live performance; however birds fed the antibiotics had a higher dressing percentage. In the second experiment, birds fed 1.0 g/ton of Avigro™ or 300 g/ton of RepaXol™, higher than suggested by the supplier, had significantly lower feed intake and significantly better feed conversion than did birds fed the negative control diet. The results of this study show some beneficial effects from the use of products containing essential oils or a mixture of essential oils plus organic acids. It appears that the response may be dose-related and that levels higher than suggested by the manufacturer may be needed to elicit this response.
  A. Teimouri , M. Rezaei , J. Pourreza , H. Sayyahzadeh and P.W. Waldroup
  The effect of energy and protein dilution in the starter period (8 to 14 days) of age, on performance and carcass characteristics of 360 Arian male chicks was studied in a completely randomized design. This experiment consisted of 6 treatments, 4 replicates, with 15 chicks per replicate. In order to dilute the diets six levels (0, 4, 8, 12, 16, and 20) percent of ground wood charcoal was used. Chicks were fed with starter and grower diet from 15 to 21 and 22 to 42 days of age respectively. During the experiment feed intake, body weight gain, feed conversion ratio were measured weekly. Mortality was measured throughout the experiment. At 43 day of age 4 chicks each treatment was selected and carcass characteristics were measured. The results indicated that dilution of diet from 8 to 14 days of age increased feed intake in this period but, the differences were not significant. With increasing dilution rate body weight gain of chicks significantly decreased in comparison to control group (P< 0.05). Due to compensatory growth after restricted period, there was not significant difference in body weight among restricted and control groups at 42 days of age. There was not significant difference among the treatments for feed conversion ratio in whole period of the experiment (8 to 42 day). Similarly, there was not significant difference among the treatments for caloric conversion ratio in whole period of the experiment (8 to 42 day). Mortality rate in restricted groups was significantly lower than control group (P< 0.05). Diet dilution hadn`t significant effect on carcass, breast meat, drumsticks, thighs, liver, intestine, abdominal fat percentages. The results of the present study indicated that broiler chicks can withstand a 7-day period (from 8 to 14 days) feed restriction with ground wood charcoal in early age without loss in performance.
  P.W. Waldroup , C.A. Fritts , C.A. Keen and F. Yan
  One experiment in wire-floored batteries and two experiments in litter-floor pens were conducted to evaluate the effects of addition of alpha-galactosidase enzyme to typical corn-soybean meal based diets for broilers. In two experiments, Avizyme 1502 was fed in conjunction with the alpha-galactosidase enzyme. In formulating test diets, soybean meal was assigned an ME value beginning at 2440 ME kcal/kg and increased on the assumption that the addition of the enzyme would increase the ME of soybean meal by 10, 20, or 30%. In two experiments, the level of supplemental poultry oil remained constant with increases in apparent ME, while in the third the level of supplemental poultry oil was reduced as the assumed ME level of soybean meal was increased. Male chicks of a commercial broiler strain were used in all experiments. Overall, the results of the three experiments suggest little if any improvement in metabolizable energy of SBM as a result of the addition of an exogenous alpha-galactosidase enzyme, as indicated by evaluation of body weight gain, feed utilization, calorie conversion, or mortality. No improvements in the above parameters were noted when Avizyme 1502 was added to the diet, alone or in combination with the alpha-galactosidase enzyme. At the present time, it does not appear that diets based on corn and SBM of average quality would benefit from supplementation with these enzymes.
  F. Yan , J.H. Kersey , C.A. Fritts and P.W. Waldroup
  It has been frequently demonstrated that addition of phytase to corn-soybean meal diets will improve the utilization of the phytate-bound P for the broiler chicken. The effect of phytase on release of other nutrients such as Ca is less clear-cut. A study was conducted to examine the effects of phytase supplementation on diets with various dietary levels of Ca and nonphytate P (nPP). A diet was formulated that provided nutrients in excess of NRC (1994) recommendations with 1.0% Ca and 0.50% nPP. By varying the amounts of dicalcium phosphate, limestone, and sand in aliquots of a common basal diet, diets were prepared with 1) Low-P and Low-Ca, 2) Low-P and High-Ca, 3) High-P and Low-Ca, and 4) High-P and High-Ca. The diets were analyzed for Ca and P content and blended as needed to provide test diets in a factorial arrangement of three Ca levels (0.5, 0.7, and 0.9%) with eight levels of nPP (0.15 to 0.50% in increments of 0.05%). These 24 diets were divided and half supplemented with 1000 units/kg of phytase. Each treatment was fed to six pens of six male broilers from one to 21 d of age. Response of both body weight and tibia ash to phytase supplementation in broilers was significantly affected by dietary Ca levels as well as dietary nPP levels. Without phytase supplementation, both body weight and tibia ash were depressed at the lowest level of nPP as dietary Ca level increased. Adding phytase to these diets improved both body weight and tibia ash as a result of increased availability of P. At both 0.5% and 0.7% Ca, the dietary Ca level was a limiting factor in maximizing tibia ash regardless of P level or phytase supplementation. These data indicate that minimal Ca appeared to be released by phytase and that no reduction in Ca level of broiler should be implemented with phytase supplementation.
  J.M. Cornelison , F. Yan , S.E. Watkins , Lloyd Rigby , John B. Segal and P.W. Waldroup
  A study was conducted to evaluate the use of hops (Humulus iupulus) in broiler diets as a potential replacement for antibiotics. Broiler diets were prepared based on nutrient specifications of top broiler companies and supplemented with either 50 g/ton penicillin or hops at 0.5, 1.0, 1.5, and 2.0 lbs/ton of feed and compared to an unsupplemented control group. Each treatment was assigned to eight replicate groups of 45 male chicks of a commercial broiler strain. The diets were fed in pelleted form with starter diets fed as crumbles. Addition of 50 g/ton of penicillin resulted in significant improvements in body weight, feed conversion, and feed efficiency at all ages, as compared to those fed the negative control. The addition of hops at 0.5 lbs per ton also resulted in significant improvements in feed conversion and feed efficiency at all ages when compared to the negative control, and also significantly improved body weight at 14 d as compared to those fed the negative control diet. At 42 d, the body weight of chicks fed 0.5 lbs of hops per ton was greater (P = 0.09) than that of chicks fed the negative control. Higher levels of hops feeding resulted in some improvements as compared to those fed the negative control; including 14 d body weight for those fed 1.0 lb per ton, and improved 1 to 42 d feed conversion and feed efficiency for those fed 1.5 lbs per ton. Results of this study suggests that inclusion of hops into diets at the rate of 0.5 lbs per ton for broiler chickens may result in improved growth rate and feed utilization in the absence of growth promoting antibiotics.
  F. Yan and P.W. Waldroup
  A study was conducted to evaluate the ability of young broiler chicks (0-3 wk) to utilize the P provided by a high available phosphate corn (HAPC) in comparison with yellow dent corn (YDC) and to determine the extent to which microbial phytase supplementation and use of 25-hydroxycholecalciferol (25-OH-D3) in the diet could reduce the requirements for P and subsequently reduce P excretion. Diets were prepared using either YDC or HAPC, which contained about the same total P but differed in phytate-bound P content. Within each corn type, diets were fortified with either vitamin D3 or 25-OH-D3 at the rate of 68.9 μg/kg diet. Treatment diets were prepared by varying the amount of dicalcium phosphate and ground limestone, and ranged from 0.09 to 0.50% nonphytate P (nPP) for YDC diets and 0.18 to 0.50% nPP for HAPC diets. Sublots of each diet were supplemented with 1000 units/kg phytase. Each diet was fed to four replicate pens of six male broilers of a commercial strain from 1 to 21 d of age. After factorial analysis, nonlinear regression analysis was conducted to estimate a nPP level sufficient for maximum body weight gain or tibia ash percentage for each corn type as influenced by phytase supplementation or use of 25-OH-D3. For broilers fed YDC diets, the estimations for maximum tibia ash were 0.40, 0.35, 0.32, and 0.27% nPP for diets supplemented with D3, D3 + phytase, 25-OH-D3, and 25-OH-D3 + phytase respectively. For broilers fed HAPC diets, substitution of D3 with 25-OH-D3 had no significant effect on tibia ash percentage and the inflection points for maximum tibia ash were 0.39 and 0.33% with and without phytase supplementation respectively. These nPP levels were sufficient to support body weight, feed conversion, or livability. The nPP in HAPC was equivalent in bioavailability to the P from dicalcium phosphate. In the absence of phytase, dry feces of broiler chicks fed YDC diets at the NRC (1994) recommended level of 0.45% nPP contained 1.19% P, whereas at the above inflection points, the fecal P content was 1.06, 1.11, 0.98, and 0.78% for chicks fed YDC diets supplemented with D3, D3 + plus phytase, 25-OH-D3, and 25-OH-D3 + phytase respectively. For chicks fed HAPC diets at the inflection points, the fecal P content was 0.84 and 0.68% with and without phytase supplementation respectively. Thus fecal P output can be reduced significantly while maintaining optimum live performance and bone mineralization by supplementation with microbial phytase, addition of 25-OH-D3, use of HAPC, reduction in dietary nPP level, or combinations of the above.
  F. Yan and P.W. Waldroup
  The study was conducted to evaluate the relative bioavailability of MINTREX® Mn, an organic source of trace minerals, compared to reagent grade Mn sulfate and reagent grade Mn monoxide in diets for young broiler chicks. Nutritionally complete diets were formulated based on nutrient specifications of top broiler producers. Each of the Mn sources was added at 0, 100, 200, 400, 600, and 800 mg/kg. Diets were adjusted for the amount of 2-hydroxy-4 (methylthio) butanoic acid added from the MINTREX® Mn. All diets were fortified with 50 mg/kg Fe from ferrous sulfate, 100 mg/kg Zn from zinc sulfate, and 10 mg/kg Cu from copper sulfate. Diets were fed in mash form. Five male chicks (Cobb 500) were placed in each of 96 pens in battery brooders; six pens were assigned to each dietary treatment. Diets were fed from 1 to 20 d at which time body weight and feed consumption were determined and birds killed by CO2 inhalation. Tibias of all surviving birds, grouped by pen, were analyzed for bone ash and Mn content. There were no significant differences among treatments for body weight, feed conversion, feed intake, mortality, or tibia ash. Significant differences in tibia Mn content were observed among source and level of Mn. Slope-ratio analysis of the response to the various products indicated that birds fed MINTREX® Mn had 15.81% higher levels of tibia Mn than those fed the sulfate form and 53.89% higher levels of tibia Mn than those fed the oxide form, indicating greater biological availability of the Mn from the MINTREX® Mn than provided by commonly used inorganic forms of Mn.
  S. Cerrate , F. Yan , Z. Wang , C. Coto , P. Sacakli and P.W. Waldroup
  Glycerine from biodiesel production was used as a pure energy source in broiler diets formulated to meet typical commercial standards. In the first experiment, glycerine was added at 0, 5, and 10% of the diet while in the second experiment glycerine was added at 0, 2.5, and 5%. Glycerine was assigned a metabolizable energy value of 3527 ME kcal/kg in formulating the diets. In each experiment the various treatments were assigned to eight replicate pens of 60 male broilers each. In the first experiment, birds fed diets with 5% glycerine did not differ significantly in performance from birds fed the control diet with no glycerine. Birds fed diets with 10% glycerine consumed significantly less feed than did those fed diets with 0 or 5% glycerine and consequently had significantly reduced body weight. It is felt that this was due in large part to reduced flow rate in the feeders used in this study as previous researchers have shown acceptance of higher levels of glycerine. In the second study, birds fed diets with 2.5 or 5% glycerine had growth rate and feed conversion that did not differ significantly from that of birds fed the diet with no glycerine. Breast yield as a percent of the dressed carcass was significantly greater for birds fed diets with 2.5 or 5% glycerine as compared to those fed the diet with no glycerine. These data indicate that glycerine from biodiesel can be a useful energy source for use in broiler diets. Concerns remain regarding acceptable levels of residual methanol resulting from separation of the fatty acids in biodiesel production.
  P.W. Waldroup , E.O. Oviedo-Rondon and C.A. Fritts
  A study was conducted to compare response of young broiler chicks to various levels of Lys and Arg using two different dietary approaches. In both diet types, a 4 x 5 factorial arrangement with Lys levels of 1.1, 1.2, 1.3, and 1.4% and Arg levels of 1.25, 1.35, 1.45, 1.55, and 1.65% was used. All other essential amino acids were at least 110% of NRC (1994). Corn, soybean meal, and corn gluten meal (CGM) of known composition were used. In the first diet set (BASAL + AA) a diet that contained 1.1% Lys and 1.25% Arg was fortified with L-Lysine HCl and L-Arg to provide the various levels of Lys and Arg. In the second dietary set (INTACT) each of the 20 diet combinations was formulated independently using intact protein sources to provide the desired Lys and Arg levels with the primary difference being in amount of CGM that varied from 0 to 33%. Data were subjected to ANOVA as factorial arrangement of treatments. Conflicting results between the two diet types existed. In BASAL+AA diets there were no significant differences in BW or FCR due to Lys; 1.35 to 1.45% Arg was necessary for optimum FCR. Although the Lys x Arg interaction was not significant the reduction in BW or FCR at high Lys with low Arg interaction was not significant, the reduction in BW or FCR at high Lys with low Arg appeared primarily responsible for the increased Arg needs. In the INTACT series there were significant interactions in BW and FCR for Arg and Lys, but these appeared to be associated with reduced performance on diets high (15-30%) in CGM. In a parallel study these levels of CGM reduced performance due to reduced feed intake. Thus, differences in diet type may influence response to Arg and Lys due to factors other than amino acid level per se.
  C. Coto, Z. Wang , S. Cerrate , F. Perazzo , A. Abdel-Maksoud , F. Yan and P.W. Waldroup
  The effect of different dietary levels of amino acids, calcium and phosphorus as influenced by phytase supplementation was evaluated in broiler chickens. The experimental design consisted of a 3 x 4 x 2 factorial arrangement with three levels of digestible lysine (1.10, 1.30 and 1.50%), four levels of calcium (0.50, 0.70, 0.90 and 1.1%) and diets containing 0.35% AP with and without phytase for a total of 24 treatments. Remaining amino acids levels were adjusted with respect to the digestible lysine level using the ideal ratios suggested by Rostagno et al. (2005). Each experimental diet was fed to six replicates pens of five male chickens during 21 days. Body weight, FCR, feed intake, bone development (TD), bone mineralization (toe ash), and phosphorus excretion as Total Phosphorus in excreta (TP), Water Soluble Phosphorus in excreta (WSP) and the WSP/TP ratio were evaluated. Birds fed lysine levels higher than 1.1% expressed better body weight in a non-linear trend. Feed intake was decreased by increasing the lysine level while feed conversion improved as lysine level increased. Increasing levels of Ca decreased feed intake, the 1.1% Ca level was detrimental for body weight. Phytase supplementation was effective to alleviate widened-suboptimal Ca:P ratios in terms of feed intake and body weight. The 1.5 % digestible lysine level improved toe ash; however, high levels of lysine were also related to a higher incidence of TD. Ca levels equal or greater than the NRC (1994) recommendation were adequate for optimum bone mineralization. Increasing levels of Ca reduced the incidence and severity of TD. Moreover, Ca levels greater than those suggested by NRC (1994) were adequate to assimilate higher lysine levels without compromising bone development. The higher lysine levels fed reduced TP in excreta but increased the WSP/TP ratio. The supplementation of phytase increased WSP and the WSP/TP ratio. Increasing levels of Ca reduced WSP and the WSP/TP ratio in excreta. Furthermore, high levels of Ca were also effective to overcome the increased WSP and WSP/TP ratio caused by the supplementation of phytase.
 
 
 
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