[Show abstract][Hide abstract] ABSTRACT: Various recommendations exist for formulating broiler diets. In this study, diet specifications were compared for four different scenarios which included U.S. Poultry Industry average, recommendations by two major breeders and Brazilian recommendations. For each of these, amino acid specifications were adjusted to a percent per Mcal basis as the various recommendations utilize different energy levels. Performance of birds formulated to different nutrient recommendations varied depending primarily upon the relative levels of crude protein, amino acids and metabolizable energy. Feeding diets higher in crude protein and amino acids tended to result in faster growth, especially in early stages, but were less efficient in conversion of crude protein and amino acids into body weight gain. Feeding diets higher in metabolizable energy tended to result in better feed conversion, however effects of dietary energy on calorie conversion were somewhat variable. Over the entire 49 d feeding period there were no significant differences among the various treatments for caloric efficiency. No economic analysis was made of the present study, as relative costs of energy and amino acids vary over time. However it is obvious that when protein costs are high relative to energy, feeding systems which recommend lower protein and amino acid levels should be more economical, while perhaps resulting in a small sacrifice in body weight gain, while feeding systems that recommend higher protein and amino acid levels might be more economical when protein is relatively lower in comparison to dietary energy costs. Because overall calorie utilization was similar among nutrient programs at the conclusion of the study, this could be used as an overall indication of economic efficiency when comparing the different nutrient programs.
International Journal of Poultry Science 11/2010; DOI:10.3923/ijps.2010.1006.1014
[Show abstract][Hide abstract] ABSTRACT: A study was conducted to evaluate the effect of the vitamin D level and source on the performance of broiler breeders and the deposition of this vitamin in egg yolk. Pullets reaching sexual maturity were depleted of vitamin D stores by feeding a vitamin D deficient diet during an eight week period. Following depletion, an experimental design was utilized consisting of a 5 x 2 factorial arrangement with four levels of dietary cholecalciferol (0, 300, 600, 1200 and 2400 IU/kg) and two levels of 25-hydroxycholecalciferol (25-OH, supplied as HyD) (0 and 68 μg/kg) for a total of 10 treatments. Each experimental diet was fed to two pens with 10 hens and 2 roosters that each received the experimental diets. Levels of 25-OH in plasma and in egg yolk were measured right after the depletion period and during the experimental phase. Performance parameters such as body weight, hen-day production, egg-shell thickness and egg mass were measured weekly. After the depletion period the level of 25-OH in plasma and egg yolk was below the detection limit confirming the depletion status. During the experimental phase the amount of 25-OH in plasma and egg yolk was higher as the cholecalciferol increased. When HyD was fed the level of 25-OH in plasma and egg yolk was higher than obtained when cholecalciferol was fed. Increasing levels of cholecalciferol improved egg shell thickness, hen-day production and egg mass. The addition of HyD improved egg-shell thickness, hen-day production and egg mass. The effect of HyD on performance was more noticeable at low levels of cholecalciferol with no difference at higher levels of cholecalciferol in the diet.
International Journal of Poultry Science 07/2010; 9(7). DOI:10.3923/ijps.2010.623.633
[Show abstract][Hide abstract] ABSTRACT: A study was conducted to evaluate the carryover effect of maternal vitamin D level and source on performance and bone development of the progeny. Breeder hens were fed a vitamin D deficient diet for two months to deplete stores. After this period, experimental diets in a factorial arrangement were fed to the hens with five levels of cholecalciferol (0, 300, 600, 1200 and 2400 IU/kg) and two levels of 25OHD3 (HyD) (0 and 68 μg/kg) for a total of 10 treatments. At the end of two months on the experimental diets two sets of eggs were hatched. The progeny obtained were placed in battery brooders to 21 days by maternal diet and received a common diet. The first hatch received a diet with no vitamin D supplement whereas the second hatch received a diet with the same nutrient composition but containing 5500 IU/kg of cholecalciferol. The first set of birds responded to the maternal diet supplementation of vitamin D mostly during the first week post hatch with no clear pattern in later stages. The progeny receiving 5500 IU/kg of vitamin D in the diet responded to the maternal vitamin D supplementation even at 21 days and in a clearer trend. Feed conversion and body weight improved as the cholecalciferol level increased and with the inclusion of HyD in the maternal diet. The response when HyD was added was more noticeable at low levels of cholecalciferol supplementation with no difference at higher levels in the hen’s diet. Bone development of the progeny was improved with the addition of HyD in the maternal diet; this response was not influenced by increasing levels of cholecalciferol in the breeder diet. This study confirms the importance of the maternal vitamin D carryover for an adequate development of the progeny. Certainly, the vitamin D carryover effect did not overcome the effect of supplementing vitamin D directly in the progeny’s diet but it was capable of improving the performance of the progeny even three weeks post-hatch when a high level of cholecalciferol (5500 IU/kg) was present in the diet of the progeny. A carryover effect of HyD when added to the maternal diet was observed in this study, thus the feasibility of using the metabolite to supply vitamin D to the developing embryo was confirmed.
International Journal of Poultry Science 07/2010; 9(7). DOI:10.3923/ijps.2010.613.622
[Show abstract][Hide abstract] ABSTRACT: The present study was conducted to investigate the effects of dietary Crude Protein (CP), lysine and amino acid balance in male broiler diets on performance (weight gain and feed conversion, feed efficiency, protein efficiency ratio). Five test diet series were used: 1) the 23% CP diet; 2) the 21% CP diet; 3) the 21% CP diet plus additional amino acids (21.68% total CP) to provide at least as much of the essential amino acids as present in the 23% CP diet; 4) the 19% CP diet and 5) the 19% CP diet plus additional amino acids (20.31% total CP) to provide at least as much of the essential amino acids as present in the 23% CP diet. For each of the five test diets series, additional Lys was added to provide total Lys levels of 1.10, 1.15, 1.20, 1.25, 1.30, 1.35 and 1.40%. This resulted in a total of 35 final experimental treatments in a 5 x 7 factorial arrangement. Each treatment was fed to 6 replicate pens of 6 male broilers in electrically heated battery brooders from 1-18 days of age. Birds fed the low-protein diets (21%) supplemented with EAAs (21.68% total CP) showed significantly the highest BW and best FCR and FE. There were no significant differences in BW between birds fed control diet (23%) and 19% CP or 19% plus EAAs (20.31% total CP) and 21% CP. FC and PER were significantly affected by dietary protein levels. FCR and FE were significantly improved and BW increased significantly by increasing dietary lysine levels up to 1.25%. An interactions of CP with or without EAAs with dietary lysine level were significant for BW. FCR, FE, FC and PER not significantly influenced by interaction. Thus, our results suggest that maximum body weight could be obtained with a 21% low-CP plus EAA supplementation which was the same as that of the chicks fed high protein diet (23% CP). Optimum dietary lysine level for performance was affected by dietary protein level and amino acid balance.
International Journal of Poultry Science 01/2010; 9(1). DOI:10.3923/ijps.2010.21.27
[Show abstract][Hide abstract] ABSTRACT: There is still a debate about the possible difference in the relative bioefficacy between DL-Met and DL-HMB as a source of methionine activity for broilers. This experiment was conducted to determine if the interaction between Arg and Met is influenced by methionine sources (MetS) and methionine level (MetL) in diets for male broilers. A 3 x 2 x 5 factorial arrangement experimental design included three total Arg levels (1.25, 1.35 and 1.45), two Met sources (DL-Met and DL-HMB) and five equimolar levels of supplemental Met (0, 0.05, 0.10, 0.15 and 0.20%) for a total of 30 treatments. Each treatment was fed to 6 replicate pens of 6 male broilers in electrically heated battery brooders from 1-18 days of age. Chickens fed the 1.25% Arg level showed a significantly higher body weight compared to other treatment groups. The FCR and FE were significantly affected by the different levels of Arg in diets. However, FI was not significantly affected by dietary Arg levels. There was no interaction between Arg-MetS and Arg-MetL or any three-way interactions. There was no significant difference between the two Met sources on the performance of broilers. Body weight and FI were not significantly affected by MetL, but an increase of MetL in basal diet significantly improved FCR and FE. The interaction between MetS and MetL had no significant effect on the performance of broilers. These results indicate that the 1.25% total Arg level was sufficient to provide optimum body weight in broiler starter diets. Both MetS had the same relative effectiveness on the performance of broilers when supplemented with equimolar amounts in diets.
International Journal of Poultry Science 01/2010; 9(1). DOI:10.3923/ijps.2010.14.20
[Show abstract][Hide abstract] ABSTRACT: Differently sized dies were used to pellet broiler starter diets formulated to meet typical commercial standards. From 0 to 13 d of age, birds in floor pens were assigned different feed forms, such as mash, crumble, or pellets made by using 1.59- and 3.17-mm dies, followed by common grower and finisher diets pelleted with a 4.76-mm die fed to 41 d. During the first 13 d, birds fed the crumble diet and the 1.59- and 3.17-min die diets had greater BW and more efficient feed conversion than did birds fed the mash feed; however, when all birds were placed on a common pelleted feed from 13 to 41 d, these positive effects dissipated as the birds grew older. Significant differences in feed intake were observable only at 13 d. Birds fed the diet pelleted with a 1.59- or 3.17-mm die had higher feed consumption than did birds fed the mash feed, but the feed intake was similar when birds were fed either the crumble or mash diet. Significant linear regressions were observed between BW or feed intake at 13 d and at 34 or 41 d. According to these correlations, the numerical differences in BW or feed intake at 7 d were maintained up to 34 or 41 d. It was likely that a 3.17-mm die diet was suitable for the starter diet because these birds became accustomed to a larger pellet size, thereby increasing the feed intake in subsequent periods. These data indicate that the small pellet diameters could be beneficial during the starter period and on subsequent performance.
The Journal of Applied Poultry Research 09/2009; 18(3):590-597. DOI:10.3382/japr.2009.00041 · 0.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Two trials with identical experimental design were conducted approximately 20 months apart to evaluate the response of broiler chickens to the addition of NuPro®, a yeast product rich in nucleotides. In both trials, four dietary treatments were compared. The first treatment contained no NuPro®. For the second treatment, the diet with 2% NuPro® was fed only the first 7 days of life while for the third treatment, 2% NuPro® was fed for the first 14 d. For the fourth treatment, 2% NuPro® was fed for the first 7 days and also during the finisher period of 35-42 d of age. In both studies, each treatment was fed to six replicate groups of 60 male broilers of a commercial strain. Response to the addition of NuPro® varied between the two experiments. In the first study, addition of 2% NuPro® to the diet resulted in improvement in feed conversion. Response varied by age of bird and time during which the NuPro® was fed. At 7 d of age, there were no significant differences between birds that had been fed NuPro® and those fed the negative control diet. At 14 d of age, there were no significant differences in feed conversion among birds fed the various treatments, but feed conversion was numerically better for those birds that had been fed NuPro® for the first 7 or 14 d. At 35 d, birds that had been fed NuPro® for the first 7 d had significantly better feed conversion than those fed the control diet with birds fed NuPro® for the first 14 d being intermediate between these two groups. At 42 d, birds fed diets with 2% NuPro® for the first 7 d or for the first 7 d followed by feeding from 35-42 d had significantly lower feed conversion than those fed the control, with those fed NuPro® for the first 14 d being intermediate between these groups. However, in the second trial there was no significant effect of inclusion of NuPro on any of the parameters evaluated. There may be nutritional differences between batches of the product that influence the response of chicks.
International Journal of Poultry Science 06/2009; 8. DOI:10.3923/ijps.2009.515.520
[Show abstract][Hide abstract] ABSTRACT: Different size pellet dies and two levels of dietary energy density were used in prestarter broiler diets formulated to meet typical commercial standards. In the first experiment, birds reared in battery brooders were offered diets containing either 0.5 or 2.5% poultry oil from 0 to 14 days. Each group of diets was assigned different feed forms such as mash continuously through the study or mash, pellet diameters of 1.59, 2.38 and 3.17 mm dies or crumbled diets from 0-7 days followed by crumbled diets to 14 days and pelleted diets to 35 days. In the second experiment, birds reared in floor litter were assigned the same treatments as the previous study except the 2 levels of poultry oil were supplied from 0-42 days of age. During the first seven days birds fed the 1.59 and 2.38 mm diameter die or crumble diets had higher body weight than did birds fed the other feed forms; however, this positive effect was dissipated as the birds grew older. The feed intake kept almost the same tendency as the body weight. The feed conversion at 7 days was improved as pellet size was reduced. It is thought that this was due in large part to better nutritive value since, birds fed crumbled and pelleted diets have almost the same feed intake but different feed conversion. Birds given the mash feed during the whole period had lower body intake and feed intake than those birds fed other feed forms. The body weights and feed conversions at 35 and 42 days were improved as the level of poultry oil increased. Improvement in feed conversion by birds fed diets with 2.38 and 3.17 mm diameter die or crumble diets at 7 days and mash or 3.17 mm diameter die diets at 42 days was observed as the dietary energy level increased. These data indicate that pellet diameters of 1.59 or 2.38 mm can be beneficial during the prestarter period and can be more useful with 2.5% poultry oil.
International Journal of Poultry Science 12/2008; 7(12). DOI:10.3923/ijps.2008.1138.1146
[Show abstract][Hide abstract] ABSTRACT: A trial was conducted to evaluate high levels of distillers dried grains with solubles (DDGS) in broiler diets throughout a 49 d growing period. Diets were formulated based on digestible amino acid content to contain 0, 10, 20, 30, 40, or 50% DDGS. Diets were formulated to be optimum nutrient density commensurate with approximately 1% supplemental poultry oil. Each dietary treatment was assigned to four replicate pens with 25 commercial male broiler chicks. Starter (0-14 d) and grower (14-35 d) diets were fed as pellets with finisher (35-49 d) diets fed as mash. Bulk density (mass/volume) was determined on all the diets. Body weights and feed consumption were determined at 14, 35, 42 and 49 d of age. At the conclusion of the study, five representative birds per pen were processed to determine dressing percentage and parts yield. Generally, the bulk density of pellet or mash diets in all different growth periods decreased as DDGS inclusion rates increased, especially in mash diets. Level of DDGS had little effect on body weight at any age until up to 20% inclusion, after which body weight declined significantly. Feed intake was not significantly affected by level of DDGS during all the periods except of 0-14 d. For the whole period (0-49 d), the estimated metabolizable energy intake by chickens was less as DDGS inclusion increased. Increasing DDGS levels significantly increased calorie conversion ratio (CCR, calorie/gain ratio), especially during the period of 0-42 and 0-49 d. Dressing percentage decreased linearly with increasing DDGS levels from 0-50%. There was a significant reduction in breast meat or leg quarter yield as a percentage of live weight with increasing DDGS inclusion, while birds fed higher levels of DDGS had higher wings as percentage of live weight. These results indicate that up to 30% DDGS could be used in broiler diets if price was justified. Inclusion of high levels of DDGS reduces the bulk density and pellet quality and may be a major reason for reduced performance. Low energy density of DDGS diets is probably the limiting factor in meeting the energy needs of the chick.
International Journal of Poultry Science 10/2008; 7(10). DOI:10.3923/ijps.2008.990.996
[Show abstract][Hide abstract] ABSTRACT: Chicken from two broiler strains known to differ in growth rate and feed conversion (Growth) and in high breast meat yield (Yield) were grown to 10 days of age on a common starter diet and from 11-49 days were provided single diets (control) or isoenergetic choices between 15% and 24% or 15% and 32% crude protein (CP) diets. The Growth strain had greater body weight and intake of feed, protein and energy at all intervals except for 42-49 d of age as well as carcass characteristic in weight basis than did Yield strain. However, the latter strain had better feed, protein and energy conversion at 42-49 d of age and breast meat yield than did the former strain. Birds fed the isoenergetic diets varying in protein content had similar body weight, feed intake, feed conversion, energy intake, energy conversion and carcass characteristic expressed in relative term as did birds fed the control diets. Only for the last period of feeding (42-49 d of age), the protein consumption and conversion by birds fed choice of 15 and 24% CP were higher than those of birds fed the control diets. The Growth strain had a slightly greater preference for the high protein diet and consequently a higher protein intake compared to Yield strain. It seems that the selection of protein density was determined by the growth rate rather than the breast yield. There was a marked preference for the low protein diet (15% CP) over the high protein diets (24 and 32% CP), but this preference was reduced when the low protein diet was offered with the 24% CP diet. The levels of selected protein of birds given the choice diets were higher than those of control diets except for the period of 10-22 d of age and increased with age. These data indicate that these choice feeding systems can detect differences in protein requirement of two strains influenced by the growth rate.
International Journal of Poultry Science 08/2008; DOI:10.3923/ijps.2008.726.737
[Show abstract][Hide abstract] ABSTRACT: A feeding trial was conducted in various levels of corn distillers dried grains with solubles (DDGS) were fed in broiler diets formulated to be either isocaloric using metabolizable energy levels similar to current U.S. poultry industry levels or formulated to contain optimum density commensurate with 1% supplemental poultry oil. In each diet type, levels of 0, 15 and 30% DDGS were incorporated. This resulted in six dietary treatments with four pens of 25 males per treatment. Diets were developed for starter (0-14 d), grower (15-28 days) and finisher periods (29-42 days) and were formulated to meet digestible amino acid specifications of a major poultry breeder, adjusted to the energy content of the diet. Bulk density and pellet quality of mixed feeds were determined. At the end of the study, five representative birds per pen were processed for dressing percentage and parts yield determination. Pellet quality decreased with increasing level of DDGS used. There was little difference in pellet quality between diets with 0 or 15% DDGS but quality deteriorated severely in diets with 30% DDGS. Diets formulated to optimum energy had better pellet quality due to lowe r supplemental poultry oil. Over the 42 days study, birds fed diets with 30% DDGS had significantly lower body weight and significantly higher feed conversion than did birds fed the control diet with no DDGS. Birds fed diets with 15% DDGS did not differ significantly in 42 days BW or feed conversion from birds fed the control diet with no DDGS nor with the birds fed diets with 30% DDGS. It appeared that a portion of the reduced performance associated with the higher level of DDGS might have been associated with the reduced pellet quality and the bulk density of the diet, rather than any nutritional deficiency. Therefore, approaches to feed manufacturing that enhance pellet quality may enhance usage of higher levels of DDGS in broiler diets.
International Journal of Poultry Science 07/2008; 7(7):630-637. DOI:10.3923/ijps.2008.630.637
[Show abstract][Hide abstract] ABSTRACT: A study was conducted to evaluate the effects of dietary levels of calcium (Ca), nonphytate P (NPP), phytase (Phy) and 25-hydroxycholecalciferol (25-OH) on live performance and bone development in male chicks fed a corn-based diet. Dietary treatments consisted of a 2×2×4×4 factorial arrangements with two levels of supplemental phytase (0 or 1200 FTU kg<sup>-1</sup>), two levels of 25-OH (0 or 69 µg kg<sup>-1</sup>), four levels of Ca (0.20% less than a 2:1 ratio of Ca to NPP; 2:1 ratio of Ca to NPP; 0.20% Ca greater than a 2:1 ratio of Ca to NPP; 0.40% Ca greater than a 2:1 ratio of Ca to NPP) and four levels of NPP (0.35, 0.40, 0.45 and 0.50%) for a total of 64 treatments. The primary basal diet was supplemented with a complete vitamin mix containing 5500 IU of cholecalciferol. Each diet was fed to six replicates per treatment; each pen having 6 birds. At 18 d birds were weighed, feed consumption determined and all birds killed for bone measurements. Toes from all birds within a pen were removed and ashed. Tibiae from both legs were removed and scored for incidence and severity of tibial dyschondroplasia and for incidence of Ca or P rickets. Ca: NPP ratios and Ca levels similar or higher than NRC (1994) recommendations appear necessary for adequate bird performance. Phy supplementation improved FCR, whereas the addition of 25-OH to diets already containing 5500 IU kg<sup>-1</sup> of cholecalciferol had a negative effect on FCR due to a possible hypercalcemia condition. Bone development was improved by increasing NPP and Ca levels. Moreover, supplementation with 25-OH was effective in reducing leg abnormalities. Addition of 25-OH helped to relieve leg problems when suboptimal Ca levels were supplied while Phy supplementation was effective for this purpose when high Ca levels were given. These additives could be seen as a strategy to alleviate problems with suboptimal Ca: NPP ratios.
International Journal of Poultry Science 07/2008; 7(7). DOI:10.3923/ijps.2008.638.645
[Show abstract][Hide abstract] ABSTRACT: An experiment was conducted to evaluate the use of distillers dried grains with solubles (DDGS) combined with glycerin in broiler diets. In a 3x2 factorial arrangement, 600 one-day-old commercial strain Cobb 500 broilers were randomly assigned to experimental diets with 0, 15 and 30% DDGS of known composition; within each level of DDGS the diets contained 0 or 5% glycerin, respectively, from 0-42 days of age. Diets were formulated to meet digestible amino acid requirements and were fed in pelleted form. Each dietary treatment was replicated 4 times. Body weight gain and feed consumption were measured and carcass characteristics were evaluated at 42 days of age. Inclusion of 30% DDGS had no adverse effect on body weight of chicks; however birds fed diets with 30% DDGS had greater feed intake and poorer feed conversion than birds fed the control diet at most age periods. This was highly correlated to the reduced pellet quality of diets containing the high levels of DDGS. Birds fed diets with 30% DDGS also had significantly reduced dressing percentage compared to birds fed the control diet with no DDGS. However, there was no adverse effect on breast meat yield related to the higher levels of DDGS inclusion. Addition of 5% glycerin from biodiesel production to the diets had no significant effect on body weight, feed intake, or feed conversion. There was no significant effect of the addition of glycerin on dressing percentage or yield of various carcass parts. With one minor exception, there was no significant interaction between addition of glycerin and level of DDGS in the diet, even though pellet quality declined when glycerin was added to the diets. Overall, the results of this study demonstrates that 15% DDGS of known nutritional quality can be utilized in diets for growing broilers with no adverse effects provided diets are formulated on a digestible amino acid basis and meet the nutritional requirements of the broiler. Higher levels may be tolerated but there may be a loss in feed conversion unless pellet quality can be improved. A loss in dressing percentage at higher levels of DDGS has been consistently noted in this and previous studies. Incorporation of 5% glycerin from biodiesel production as a source of energy appears satisfactory.
International Journal of Poultry Science 07/2008; 7(7). DOI:10.3923/ijps.2008.646.654
[Show abstract][Hide abstract] ABSTRACT: Two consecutive experiments compared different concentrations of inorganic trace minerals in broiler production under different ambient temperature. Both experiments had six treatments, consisting of 100, 80, 60, 40, 20 and 0% of normal trace mineral premix (TMP) inclusion rate with eight and four replicates of sixty male broilers in the first and second experiments, respectively. Experiment 1 began on January 9th and finished on February 20th while Experiment 2 began on July 19th and finished on August 29th. Body weight and feed consumption were determined at 14, 35 and 42 days. At 42<sup>nd</sup> day two birds per pen were killed and the tibia removed for bone ash determination. In Experiment 2, cohort birds were fed in battery pens from 35 to 37 days. with excreta samples collected for trace mineral analysis. In Experiment 1, birds with no TMP had significantly decreased body weight over all growth periods. Birds fed diets with 20% of normal TMP did not differ in performance from those fed higher levels up to 100% of normal addition rates. There was no difference in any growth variables in Experiment 2 when higher environmental temperatures were in effect. Reduction of TMP in broiler diets could reduce mineral excretion to environment. Levels of Fe, Cu, Mn and Zn in broiler excreta decreased when mineral premix levels were reduced.
International Journal of Poultry Science 07/2008; 7(7). DOI:10.3923/ijps.2008.625.629
[Show abstract][Hide abstract] ABSTRACT: Male broilers from 11 to 49 days of age were assigned to one of four feeding treatments: Single diets (control), a choice of starter and finisher diets, a choice of high energy and high protein diets in relation to amino acid: lysine ratio and a choice of high energy and high protein diets in relation to amino acid: protein ratio. Birds fed both energy-protein treatments had worse body weight, feed conversion and carcass characteristics than did birds fed single diets or starter and finisher diets. The high energy-protein diets formulated in relation to lysine had the poorest carcass characteristics for all parameters except for wing and leg quarter yields. Birds given the choice feeding systems selected more high energy diet than high protein diet especially during the period of 11 to 22 days of age. Choice-fed broilers of both energy-protein treatments consumed less protein (total intake or percentage of consumed feed) for all periods, whereas these birds consumed similar energy intake at all age periods except for 42 to 49 days of age and higher energy density than did birds fed the other two feeding systems. As the choice-fed birds grew older, the selected energy content tended to wane while the selected protein contents tended to increase. These data indicate that the high protein diet formulated with amino acids in relation to lysine did not overcome the failure of choice feeding with high energy and high protein diets to sustain productivity since energy may be the driving force for feed selection.
International Journal of Poultry Science 12/2007; 6(12). DOI:10.3923/ijps.2007.846.854
[Show abstract][Hide abstract] ABSTRACT: A study was conducted utilizing a 2 x 2 x 4 x 4 factorial arrangements in which a nutritionally adequate diet was fed with and without 1200 FTU/kg of phytase and with or without 69 ÃŽÂ¼g/kg of 25-hydroxycholecalciferol, four levels of nonphytate phosphorus (NPP) (0.35, 0.40, 0.45, and 0.50%) and four levels of calcium (2:1 Ca:NPP ratio, 0.2% Ca less than the 2:1 ratio, 0.2% Ca more than the 2:1 ratio, and 0.4% Ca more than the 2:1 ratio) for a total of 64 treatments, each fed to two replicate pens of five male broilers in wire-floored battery brooders. At 14 d of age excreta samples were collected, frozen, freeze dried, and analyzed for total P (TP), Ca, and water-soluble P (WSP). The ratio of WSP/TP was calculated from these data. The TP, Ca and WSP in excreta increased as the NPP content of the diet increased. Phytase supplementation reduced TP and Ca but increased WSP concentration and the WSP/TP ratio; this effect might be reversed if levels of NPP lower than those evaluated in the present study are utilized to account for the improvement on phytate phosphorus digestion. The addition of Hy-D reduced TP and Ca concentration in broiler excreta. The most remarkable effect was seen by increasing dietary calcium levels above the 2:1 Ca:NPP ratio typically used in the poultry industry. As the dietary Ca increased, there were significantly reduced excreta levels of TP, WSP and the WSP/TP ratio was significantly reduced. Compared to chicks fed diets with the 2:1 Ca:NPP ratio, the WSP in excreta was reduced 40% by adding 0.20% more Ca and 54% by adding 0.40% more Ca. As the WSP fraction of broiler litter is the primary concern in eutrophication, increasing the dietary Ca level in conjunction with feeding closer to the P requirement should be a cost-effective means of combating the adverse effects of broiler litter on pastures.
International Journal of Poultry Science 12/2007; 6(12). DOI:10.3923/ijps.2007.937.943
[Show abstract][Hide abstract] ABSTRACT: Male broilers of a commercial strain were grown to 10 d of age on a common starter diet and then from 11 to 49 days were offered single diets (control), a choice of starter and finisher diets, isoenergetic choices between 12 and 24 or 32% Crude Protein (CP) diets and isoenergetic choices between 15 and 24 or 32% CP diets. Birds fed the isoenergetic diets varying in protein content had almost similar body weight, feed intake, energy intake and carcass characteristics as did birds fed the control diets or the choice of starter and finisher diets. In general the feed and energy conversions by birds given the choice between 12 and 24 or 32% CP diets were worse than those of birds given the other feed systems; however, the protein consumption and conversion by birds fed the former diets were lower than those of birds fed the latter diets. There was a marked preference for the low protein diets (12 and 15% CP) over the high protein diets (24 and 32% CP), but this preference was reduced when the low protein diets were offered with the 24% CP diet. The levels of protein selected of the isoenergetic diets varying in protein content were lower than those of control diets or choice between finisher and starter diets and declined with age except for the last week of the experiment, possibly due to feed form variation. Birds given the choice between 15 and 24 or 32% CP diets had similar performance, except for slightly better protein conversion but slightly worse energy conversion, as those fed control diets or given a choice of starter and finisher diets; even though these choice-fed broilers chose lower protein contents than did birds fed the other two systems. These data indicate that choice of isoenergetic diets varying in protein content can be used to determine protein requirements of broilers, being more effective and efficient with a narrow range of two protein contents.
International Journal of Poultry Science 12/2007; DOI:10.3923/ijps.2007.916.924
[Show abstract][Hide abstract] ABSTRACT: Chickens from two broiler strains known to differ in growth rate and feed conversion (GROWTH) and in high breast meat yield (YIELD) were grown to 10 days of age on a common starter diet and from 11 to 49 days were provided single diets (control), a choice between high energy and high protein diets, or a choice between starter and finisher diets. Overall the YIELD strain had greater body weight, feed intake and breast yield than did GROWTH strain. However, the YIELD strain had better feed conversion only when offered a choice of starter and finisher diets. Birds fed single diets and Starter-Finisher diets had better body weight, feed intake, feed conversion and breast yield than those birds fed Energy-Protein diets. Birds fed both choice feeding systems selected more high energy diets than high protein diets especially during the period of 11 to 22 d of age. The YIELD strain had a preference for the high protein diet and consequently had greater protein intake and average dietary protein content than did the GROWTH strain, while the former ate more energy intake but less energy content than did the latter. Birds given choice of the energy and protein diets had less protein intake and content for all periods, whereas these birds chose less energy intake for the period of 22 to 42 d of age and a higher energy level than did birds fed the other two feeding systems. These data indicate that choice feeding systems can identify differences in performance according to the selected nutritional needs for new strains of broilers.
International Journal of Poultry Science 10/2007; 6(10). DOI:10.3923/ijps.2007.713.724
[Show abstract][Hide abstract] ABSTRACT: This study was conducted to evaluate the use of moderate to high levels of DDGS in broiler diets and to evaluate the effects of rapid and multiple changes in level of DDGS during the growth period. Diets were formulated to contain 0, 15, or 30% DDGS with diets formulated on the basis of digestible amino acids to meet levels typical of the U.S. broiler industry. Groups of birds were fed diets with these three levels of DDGS on a constant basis from 0 to 42 d of age. Other groups were fed 0 and 15% or 0 and 30% DDGS on alternate week basis, with one group starting with diets containing no DDGS and other groups starting with diets containing 15 or 30% DDGS. Four pens of 25 male broilers were fed each of the dietary treatments. At the conclusion of the study five representative birds per treatment were processed to determine dressing percentage and carcass yield. Birds fed diets containing 15% did not differ significantly in live performance or carcass characteristics from birds fed diets with no DDGS, whether fed on a continuous basis or alternated weekly between 0 and 15% DDGS. Birds that were continuously fed diets with 30% DDGS had significantly reduced body weight and feed intake at 35 and 42 d compared to birds fed the control diet with no DDGS and had reduced breast meat yield. When birds were fed diets with 0 or 30% DDGS alternating on a weekly basis live performance was approximately midway between that of birds fed diets with 0 or 30% continuously and similar to that of birds fed 15% DDGS on a constant basis, but breast meat yield tended to be reduced. The results of the study demonstrated the effective use of diets with 15% DDGS when formulated on a digestible amino acid basis and showed that abrupt removal of this level of DDGS did not adversely affect performance of broilers. Further studies are suggested to quantify reasons for reduced performance when fed diets containing 30% DDGS.c
International Journal of Poultry Science 10/2007; 6(10). DOI:10.3923/ijps.2007.725.731
[Show abstract][Hide abstract] ABSTRACT: An experiment was conducted to evaluate different levels of “new generation ” distillers dried grains with solubles (DDGS) in broiler diets throughout a 49 d growing period, based a standardized nutrient matrix derived from a composite of literature values. Diets were formulated based on digestible amino acid content to typical U.S. poultry industry standards to contain 0, 5, 10, 15, 20, or 25 % DDGS. Each dietary treatment was assigned to four replicate pens of 25 male chicks of a commercial broiler strain. Starter diets (0 to 14 d) were fed as crumbles; grower (14 to 35 d) and finisher (35 to 49 d) diets were fed as pellets. Bulk density (mass/volume) was determined on the crumbled or pelleted feeds. Body weights and feed consumption were determined at 14, 35 and 49 d of age. At the end of the study five representative birds per pen were processed to determine dressing percentage and parts yield. Increasing the DDGS in the diet generally reduced the weight per volume of feed. There were no significant effects of DDGS level on body weight; however chicks fed diets with 25 % DDGS consumed significantly more feed and had poorer feed conversion compared to chicks fed the control diet with no DDGS. Birds fed 15 and 25 % DDGS had significantly lower dressing percentage than did birds fed the control diet with no DDGS. Birds fed diets with 25 % DDGS had significantly lower breast weight when expressed as percentage of live weight but not when expressed as a percentage of the carcass weight, compared to birds fed the control diet with no DDGS. Wing weight as
International Journal of Poultry Science 07/2007; 6. DOI:10.3923/ijps.2007.470.477