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Articles by C.N. Coon
Total Records ( 19 ) for C.N. Coon
  M. de Beer and C.N. Coon
  Two experiments were conducted to determine effects of Everyday (ED) or Skip-a-day (SK) feeding and dietary L-carnitine on lipid metabolism and stress in broiler breeders. In Experiment 1 a 2x2 factorial design was used to compare feeding regimens (ED vs SK) and L-carnitine supplementation (0 vs 50 mg/kg). L-carnitine supplementation began at d 1 and lasted throughout the 45 weeks experimental period. SK programs were implemented from 28 days of age to 5% production. Parameters measured included in vitro Lipogenesis (IVL), Heterophil/Lymphocyte ratio (H/L) and yolk IgY content. Liver and blood samples were taken 1 h after feeding, at various intervals during the rearing and production periods. Both SK feeding and L-carnitine increased liver wts during rearing but differences dissipated after onset of lay. Part of the increase in liver weight in SK birds was due to higher lipid contents. L-carnitine tended to reduce liver lipid during rearing. IVL was increased by SK feeding during the rearing period. L-carnitine and SK feeding interacted to increase IVL at 20, 22 and 27 weeks. H/L was elevated at 7 weeks in SK birds, but no differences were observed after that. Neither L-carnitine nor feeding regimens affected maternal IgY transfer to egg yolks. In Experiment 2, the same effects were tested but a low density grower diet was used from 4-18 weeks. The grower diet had 9% less energy and 7% less protein than in experiment 1. Liver wt was increased in SK and L-carnitine supplemented birds up to 20 weeks. By 40 weeks, ED birds had higher liver weights than SK. Liver fat was generally higher in SK birds than ED during rearing. SK feeding increased IVL but unlike Experiment 1, L-carnitine did not. H/L ratio was elevated in SK up to 20 weeks of age after which no differences occurred. L-carnitine did not affect H/L. In conclusion, feeding regimens and L-carnitine can alter hepatic lipid synthesis. Feeding regimens like SK, incorporating lengthy periods without feed can result in elevated H/L ratios but birds are generally able to adapt to such regimens over time
  M. de Beer and C.N. Coon
  An experiment was conducted to compare Everyday (ED) and Skip-a-day (SK) feeding programs and early Slow growth (SLOW) and Broilerized (BROIL) treatments. Feed restriction programs were implemented from 4 weeks to 5% production. The SLOW group was fed to reach 75% of standard BW by 12 weeks and then to reach standard BW by 21 weeks. The BROIL group was fed ad libitum till 7 weeks and then severely restricted to reach standard BW by 21 weeks. Parameters measured included BW, uniformity, age at Sexual Maturity (SM), total and settable egg production, body composition, liver size and composition, in vitro Lipogenesis (IVL) and Heterophil-Lymphocyte ratio (H/L). Breeder production performance was evaluated through 45 weeks of age. Birds fed ED grew more efficiently than SK or SLOW. The BROIL treatment resulted in significantly worse feed utilization than all other groups. Frame size was consistently greater in BROIL pullets and consistently smaller in SLOW pullets. Birds fed ED reached SM before SK, who in turn reached SM before SLOW or BROIL birds. Egg production was significantly higher in ED than SK, which in turn was higher than either SLOW or BROIL. The difference of nearly 17 total eggs per hen between ED and BROIL hens could not be explained by differences in BW or body composition. Liver weight and IVL was elevated in SK and SLOW pullets above ED pullets during rearing. Liver weight and IVL were lower in BROIL pullets than other groups during rearing, but after photostimulation dramatic increases in liver weight and IVL resulted in this trend being inverted by 27 weeks. As an indicator of stress, H/L ratios were elevated above ED pullets in SK, SLOW and BROIL pullets at various times during rearing. These times generally coincided with the periods of most severe feed restriction. Feeding regimens and growth curves have a major influence on efficiency and reproductive performance in broiler breeders. These effects were not attributable solely to differences in BW and body composition. The depression of IVL in broilerized pullets even after restricted feeding was implemented was of great interest and warrants further examination.
  M. de Beer and C.N. Coon
  Two experiments were conducted to determine the effect of Everyday (ED) or Skip-a-day (SK) feed restriction programs and L-carnitine supplementation on breeder reproductive performance. In Experiment 1 a 2 x 2 factorial design was used to compare feeding regimens (ED vs. SK) and L-carnitine supplementation (0 vs 50 mg /kg). L-carnitine supplementation began at day 1 and lasted throughout the 45 week experimental period. SK feeding programs were implemented from 28 days of age to 5% production. Feed allocation was adjusted to ensure equal BW between groups. At 21 weeks, 60 pullets from each treatment combination were housed individually. Feeding ED improved the feed conversion ratio by 0.24 units for 21 week pullets, resulted in 3 days earlier attainment of Sexual Maturity (SM), produced 4.6 more total eggs and 5.0 more settable eggs than SK fed pullets. Uniformity was less for ED fed pullets (2.07 higher CV). Egg size was increased by 1.16g with dietary L-carnitine. Body composition was not affected by either feeding regimen or L-carnitine. In Experiment 2, the same effects were tested but a low density grower diet was used from 4-18 weeks. L-carnitine was supplemented from day 1 and SK programs began at day 28 and extended to 5% production. Feed allocation was adjusted to maintain equal BW and 80 pullets per treatment were individually housed at 21 weeks. L-carnitine and ED feeding through 21 wk improved the FCR by 0.06 and 0.12 units, respectively. Feeding ED resulted in 5.8 days earlier SM, 4.7 more total eggs and 4.4 more settable eggs than SK. Uniformity was not affected by feeding regimen or L-carnitine. Carcass fat was reduced and carcass ash was increased by L-carnitine supplementation at 22 weeks. It was concluded that ED fed breeders are more productive than SK fed breeders primarily because of earlier SM. ED fed breeders are more efficient than SK breeder pullets because there are less nutrients wasted for tissue replenishment. Feeding breeder pullets ED with low energy density diets helped eliminate uniformity differences for pullets fed ED and SK feeding regimens. Breeders fed L-carnitine during 21 wk rearing period improved the FCR by 0.06 units for both Experiment 1 and 2. While, the effect of L-carnitine on total egg production was not significant, L-carnitine supplemented birds produced 3.9 and 2.7 more total eggs at 45 weeks than non-supplemented birds in Experiments 1 and 2 respectively. The consistency of the results and the associated p-values (p = 0.12; p = 0.13) for total egg production in the two experiments suggest that L-carnitine may have some beneficial effects on egg production. Breeders fed carnitine also showed significant increases in EW in Experiment 1 and near significant (p = 0.13) increases in EW for the second experiment. Carnitine was unable to attenuate the negative effects of SK feeding associated with the lengthy fasting periods.
  M.K. Manangi , J.S. Sands and C.N. Coon
  A 42 d broiler experiment was conducted to determine the effect of added Escherichia coli phytase (Phyzyme-XP 5000G) to low and high phytate P (PP) diets on performance and nutrient digestibility. The experiment consisted of 12 treatments with 2 levels of PP: Low-Phytate (LP) group-0.24% and High-Phytate (HP) group-0.32%. Both LP and HP groups had respective Positive Controls (PCs) with 0.39% in the starter and 0.29% NPP in the grower, respectively and 5 basal diets with graded levels (0, 250, 500, 750 and 1000 FTU’s/kg diet) of added phytase. The HP diets contained additional PP because canola and rice bran were substituted for part of the corn and soybean meal. A significant (p<0.001) phytase effect was found for Body Weight Gain (BWG) Feed Intake (FI) and Feed:Gain (F:G) ratio on d 42 and ileal P digestibility and % tibia ash for both LP and HP groups on d 42. Supplementation of 250 FTU’s phytase/kg diet for both LP and HP basal diets produced equivalent body weights (p>0.05) to comparable respective PCs. Supplementing 500 FTU’s phytase/kg diet in both LP and HP groups resulted in a comparable (p>0.05) % tibia ash to respective PC groups. The litter Total Dissolved P (TDP) and Water-Soluble P (WSP) of pens from broilers fed either the LP or HP basal diets with increasing concentrations of phytase were not significantly different (p>0.05) compared to the respective PCs. The research shows that adding feed phytase does not necessarily mean that TDP and WSP will be reduced. The P equivalency determined from 42d ileal digesta for added phtase with the LP and HP diets showed that broilers fed the HP diet with 1000 FTU phytase provided 0.17% digestible P compared to 0.13% digestible P from the LP diet. In order to decrease P excretion in broilers, added feed phytase should be considered equal to feed phosphates for providing available P in the gastrointestinal tract and the combination needs to be low enough for optimum performance and retention.
  M.K. Manangi , J.S. Sands and C.N. Coon
  A 42 d broiler experiment was conducted to determine the effect of added Escherichia coli phytase (Phyzyme-XP 5000G) to low and high phytate P (PP) diets on performance and nutrient digestibility. The experiment consisted of 12 treatments with 2 levels of PP: Low-Phytate (LP) group-0.24% and High-Phytate (HP) group-0.32%. Both LP and HP groups had respective Positive Controls (PCs) with 0.39% in the starter and 0.29% NPP in the grower, respectively and 5 basal diets with graded levels (0, 250, 500, 750 and 1000 FTU’s/kg diet) of added phytase. The HP diets contained additional PP because canola and rice bran were substituted for part of the corn and soybean meal. GE retention was significantly improved 6% percentage points for 42 d broilers fed either LP or HP diets with added phytase however a significant interaction indicated the improvement in energy retention caused by phytase was primarily from the broilers fed the HP diet. Overall there was no significant main effect of phytase on GE retention of 21 d broilers but the energy retention of HP diet was significantly less than for LP fed broilers and broilers fed the LP diet showed a significant improvement an interaction suggested the phytase would only benefit broilers fed the LP diet. The ileal % digestibility of threonine, tryptophan and serine were affected by PP levels, phytase and the interaction of PP and phytase for 21 d broilers, whereas cystine was the only amino acid to show all three main effects for 42 d broilers. In general, the interaction of phytase and PP for ileal digestibility of specific amino acids was caused by a lack of positive response of phytase when added to the HP diet for 21 d broilers, whereas phytase showed an influential trend of improving ileal digestibility of all amino acids (p = 0.1284) in either of the HP or LP diets for the older 42 d broiler. The slight improvement of ileal digestible amino acids seemed to correlate with a 6.2 percentage point improvement in % ileal N digestibility for 42 d broilers fed either the LP or HP diets. Broilers fed the LP PC diet had a higher % ileal nitrogen and energy digestion than broilers fed the HP PC diet at 21 d but there was no difference in 42 d broilers fed the two different PP diets. In summary adding phytase to broiler diets improved energy utilization by 2.1-4.9% for both LP and HP fed broilers and an 1.9-6.1% improved ileal % tAA digestibility for LP fed broilers.
  R.D. Ekmay and C.N. Coon
  A 40-wk study was conducted to assess the effects of limestone particle size on the production performance, skeletal integrity and Ca/P balance of three broiler breeder purelines. A flock of LINE A, LINE B and LINE C broiler breeders were reared according to Cobb 500 guidelines (Cobb-Vantress, 2005) and transferred to a production house at 21 wks of age. Each line was split into two groups consisting of 66, 68 and 62 hens for the LINE A, LINE B and LINE C lines, respectively and fed a diet that differed only in the inclusion of either large (3489.7 microns; 38.5% solubility) or small particle (185.5 microns; 58.8% solubility) limestone. Production performance, egg quality, breeder skeletal integrity, reproductive performance, progeny performance and Ca/P balance were monitored. LINE B produced the most eggs per hen housed and highest egg number, followed by LINE C and LINE A, respectively. Egg weight, specific gravity and shell weight were also superior in LINE B compared to the other purelines. The % P retention did not differ across purelines, but Ca retention was also highest in LINE B. Breeder skeletal integrity and progeny bone quality were higher in LINE C. The addition of large particle limestone in lieu of small particles did not provide a consistent effect in production performance but significantly improved shell quality (P = 0.0013), bone quality (P = 0.0341). The large genetic differences in purelines compared to parent stock may uniquely alter the effects of particulate calcium on production performance; yet large particle limestone provided the boost in shell quality and bone quality reported by others. In summary, LINE A, LINE B and LINE C purelines utilize Ca and P differently and have unique genetic potential for hatching egg production, egg shell quality, breeder bone ash and progeny bone ash.
  R.D. Ekmay and C.N. Coon
  A 40-wk study was performed to assess the effects of reduced dietary Non-Phytate Phosphorus (NPP) on broiler breeder performance, progeny quality and P balance. Seven hundred Cobb 500 chicks were reared according to Cobb guidelines (Cobb-Vantress, 2005) and transferred to a production house at 21 wk. At 24 wk, 285 birds were switched over to one of five experimental diets (5 groups of 57) that differed only in NPP. Phosphorus levels ranged from 0.2% to 0.4% NPP in 0.05% increments; and corresponded to a daily intake of 288, 360, 432, 504 and 576 mg at peak. Production performance, egg quality, breeder and progeny skeletal quality, hatchability, progeny weight and P retention were monitored throughout the experimental period. Results show that total egg production, egg number, age at sexual maturity and egg weight were not negatively effected by lowering NPP levels to 0.20% (288 mg/day). Shell quality, though statistically impacted by NPP level, remained at high levels for all treatments (above 1.081). Reproductively, reduced dietary NPP did not negatively impact hatchability or subsequent progeny performance. Day old progeny wt and progeny bone quality were not significantly different from the breeders fed different NPP intake. Breeder tibia ash and relative strength was impaired at 0.20% NPP. The % total P (TP) retention showed a negative linear response with increasing dietary NPP, although absolute P retained increased with increasing dietary NPP. The amount of P deposited into the egg was not different among the treatment groups. Results appear to indicate that 360 mg NPP/day at peak (0.25% NPP) is sufficient for breeder hen performance, progeny 1 d wt and progeny skeletal quality. Breeder hens are able to maintain their performance by mobilizing bone reserves to meet the demands of egg formation and utilize dietary sources to replenish these reserves.
  Z.L. Zhou , N.C. Rath , G.R. Huff , W.E. Huff , K.S. Rasaputra , C. Salas and C.N. Coon
  The effect of two nutritional supplements, a Yeast Extract (YE) and a vitamin D3 formulation (VD) on growth and structural properties of bones from turkeys, transiently subjected to a simulated stress using Dexamethasone (Dex) administration, was determined. The birds were fed diets with or without YE or VD supplements during wks of 6, 11 and 15 post hatch. At weeks 6 and 15 of age, half of the birds in each treatment group received 3 intramuscular injections of Dex at concentrations of 2 mg/kg BW on 3 alternating days to induce simulated stress. At 16 wk of age, the birds were weighed, bled prior to euthanasia and the tibia were harvested at necropsy to determine their mineral content, density and biomechanical properties. Bone Mineral Density (BMD) and Bone Mineral Content (BMC) of whole tibia were determined by Dual Energy X ray Absorptiometry (DEXA) and the biomechanical properties using Instron material testing machine. The ash yield and bone densities were determined using bone marrow free mid diphyseal segments manually by ashing and Archimedes principle. Serum Ca, P, protein and alkaline phosphatase measured using a clinical chemistry analyzer. Neither YE nor VD had any effect on body or bone weights by itself or in combination. Dex reduced both BW and bone weights. DEXA estimated BMD and BMC of whole tibia were reduced in Dex-stressed birds but it was not evident measuring the diaphyseal bone and ash densities. Dex treatment lowered the breaking strength and the plasticity of bone but had no significant effect on its stiffness. Dex treated turkeys showed higher relative bone weights indicating faster recovery of bones from Dex induced growth suppression. Overall, these results suggest that decreased bone mass due to Dex-induced growth suppression reduces bone strength and can alter some structural properties. Intermittent treatment with either VD or YE individually or in combinations do not provide much protection against the negative effects of stress.
  R.D. Ekmay and C.N. Coon
  A 2 x 5 factorial production and balance study with 90 broiler breeders was performed to assess the effects calcium particle size and NPP levels. Cobb 500 broiler breeders, 24 wk of age, were fed 4.68 g Ca intake at peak using 2 particle sizes of dietary calcium carbonate (185.5 microns; 58.8% solubility and 3489.7 microns; 38.5% solubility) and 5 levels of dietary %NPP (0.2% to 0.4% NPP in 0.05% increments; corresponding to a daily intake of 288, 360, 432, 504 and 576 mg at peak intake). Egg production, specific gravity and egg wt were monitored from 24 to 40 wk of age and tibia relative strength at 45 weeks. A retention study was performed at 31 wk of age to determine Ca and P balance. No differences were noted in breeder bone integrity due to NPP intake, though eggs per hen housed and egg shell quality were affected. The breeders fed 288 mg NPP produced the largest number of eggs. The % P retention showed a positive linear response to increasing dietary NPP for breeders fed large particle limestone; but no response in hens fed small particle limestone. The amount of P excreted was increased with P intake but was minimized for hens fed large particle limestone. The amount of Ca excreted was significantly increased with increasing P intake. There was a significant linear increase in excreta Ca and linear decrease in % Ca retention for breeders fed increasing P intake along with small particle calcium but the amount of Ca excreted and % Ca retention was not statistically impacted by particle size. Feeding breeders large particle calcium carbonate increased the egg weight but did not significantly improve shell quality or tibia bone strength. The increased egg weight response for breeders fed large particle calcium carbonate in this short term experiment may have reduced the opportunity for large particle Ca to significantly improve egg shell quality. It can be concluded that particulate Ca sources can improve breeder performance and that dietary levels as low as 0.20% NPP (288 mg/day NPP intake) can be fed without impacting breeder performance; however dietary levels of >0.25%NPP (360 mg/day NPP intake) ensure adequate skeletal integrity.
  M.E. Reyes , C. Salas and C.N. Coon
  Mathematical modeling is an accounting tool that can be used for predicting the nutritional requirements for poultry with different genetic strains, environments and stages of meat gain or egg production. Models are also useful for describing or predicting the animal’s production process. Modeling the daily ME requirement of broiler breeder hens requires partitioning Metabolizable Energy (ME) requirements into maintenance, egg mass and body weight gain. Determining the daily energy requirement for maintenance and egg production in breeders requires separating the daily energy needs for egg production from energy needs of maintenance. The objective of the research reported herein was: 1.) to obtain information about body tissue changes and egg composition for breeders being fed specific intakes of ME in a set environment and 2.) to evaluate a technique for partitioning the Metabolizable Energy (ME) requirement into maintenance and production for each individual breeder. An estrogen antagonist, TAMOXIFEN ([Z]-1-1[p-Dimethylaminoethoxyphenyl]-1,2-diphenyhl-1butene) (TAM), was used to separate the ME needs into two periods: laying and non-laying. Broiler breeder hens were provided TAM to stop egg production and their individual ME requirement for maintenance determined. Each broiler breeder resumed egg production when TAM was withdrawn and the ME requirement for egg production and BW gain determined. The estimated ME required for maintenance for breeders (MEm) housed in a constant 21C was 98.3 kcal/kgBW0.75, MEg for gain was 5.6 kcal/g and MEe for egg mass was 2.4 kcal/g. The energy efficiencies for protein gain (kp), fat gain (kf) and egg calories (ke) were 34%, 79% and 65.7%, respectively. The use of TAM provided an opportunity to estimate breeder maintenance requirements and reduce the interdependence in estimating factorial coefficients while partitioning production energy.
  J.A. England , C. Salas , R.D. Ekmay and C.N. Coon
  Most methods for evaluating shell quality and egg components are destructive and time consuming. Four trials were conducted to investigate the use of Dual Energy X-ray Absorptiometry (DXA) as a fast and non-destructive method for evaluating shell quality and measuring the components of broiler breeder eggs. In Trial 1, 180 eggs were scanned with a GE Lunar Prodigy DXA. The eggs were also evaluated by traditional methods that required breaking the eggs for shell quality evaluation and egg components (shell, albumen and yolk) weighed. Values obtained from the DXA scans were subjected to stepwise regression analysis to develop prediction equations. Prediction equations were developed for the weight of egg components (egg, yolk, albumen and shell) and parameters of shell quality (shell weight, thickness and calcium content). In Trial 1, the r2 values for the prediction equations using DXA values were 0.9961, 0.9692, 0.9843, 0.6891, 0.8499 and 0.5738 for the total egg weight, shell weight, shell calcium content, shell thickness, albumen weight and yolk weight, respectively (P>F, <0.0001). In Trial 2, 180 eggs were scanned to validate the prediction equations developed in Trial 1. Results from Trial 2 indicate that the prediction equations using DXA values are an effective method for predicting total egg weight, shell weight, shell calcium content, shell thickness, albumen weight and yolk weight (P>F, <0.0001). In Trial 3, 250 hatching eggs were scanned to determine the affect of scanning on hatchability. DXA scanning had no negative effect on hatchability, hatch chick weight or hatch residue breakout. In Trial 4, the specific gravity of 400 hatching eggs was determined by flotation in salt solutions. The eggs were then scanned with the DXA and values obtained from these scans were used to calculate SWUSA and shell:egg weight ratios. The SWUSA and shell:egg weight ratios determined by DXA scan were useful in predicting eggshell quality and correlated closely with actual specific gravity values (r = 0.7849, p<0.0001). A SWUSA of 75.1 and specific gravity of 1.081 corresponded to a shell:egg weight ratio of 0.0895 and 0.0924, respectively. Following the evaluation of egg shell quality by DXA and specific gravity, the 400 eggs were incubated to determine hatchability. Shell:egg weight ratios less than 0.0895 significantly increased the number of early dead (p = 0.02) during the hatchability study. By defining the scan area it is possible to scan and analyze 140 eggs per hour for all egg components and shell quality. DXA offers the primary breeder or researcher a method for selecting individual hens, based on egg component and shell quality profiles, which may improve the performance of the progeny.
  M.E. Reyes , C. Salas and C.N. Coon
  A 10 wk feeding experiment was conducted to develop a model for predicting the ME requirement for broiler breeder hens housed in different environmental temperatures. Three groups of 50 Cobb 500 broiler breeder hens were individually housed in breeder cages located in environmentally controlled rooms set at 15.5, 23 and 30°C. Each breeder was given an intramuscular injection of Tamoxifen (TAM) (5 mg/kg BW) in corn oil at days 1 and 4 to stop egg production. Ten breeders from each environmental temperature were sacrificed for carcass composition analysis at the beginning of the study. Breeders, during the non-laying period, housed at 15.5°C were fed 100 g providing 285 kcal MEn/b/d (2851 kcal/kg; 16%CP) and breeders housed at 23°C and 30°C were fed 93 g providing 265 kcal MEn/b/d of same diet. Five breeders were sacrificed from each environmental room after the breeders resumed egg production. The ME requirement for maintenance (MEm) determined during the non-laying period was 104.3, 98.1 and 99.4 kcal/kg0.75 for birds housed in 15.5, 23 and 30°C, respectively. At first egg, 136, 130 and 128 g/bird/d of same diet previously fed during the non-laying period provided 388, 371 and 365 kcal MEn/b/d to broiler breeder hens housed at 15.5, 23 and 30°C, respectively. The egg number, egg weight and BW change for each breeder during egg production was evaluated through the remainder of the 10 wk period. At the end of the trial, all birds were sacrificed and frozen at -4°C for carcass composition analysis. Body weight data collected during the non-laying period was used to construct a single equation by plotting Metabolizable Energy (ME) against body weight change (BWΔ) for each individual hen to calculate the MEm. Egg production and egg weights were recorded daily after egg production resumed. The MEg and MEe requirement for BW gain and egg production were determined for breeders in each of the environmental temperatures based on the energy content of carcass and egg mass and the respective efficiency of energy utilization. The average MEg and MEe for the three environmental temperatures was 5.8 kcal/g and 2.3 kcal/g, respectively. Three equations were developed from the feeding experiment to predict ME needs for breeders: Eq. 1: (ME = BW0.75 [111.9 - 0.46 T] + 5.8G + 2.3EM); Eq. 2: (ME = BW0.75 [110.3 - 0.47 T + 0.055 (T - 22.5)2] + 5.8G + 2.3EM); Eq. 3: (ME = BW0.75 [111.02 - 0.49 T + 0.049 (T - 22.07)2] + BWΔ (1/0.77 x ERf + 1/0.37 x ERp) + ECE/0.73 x EM), where ME = Metabolizable Energy (kcal), BW = Body Weight (kg0.75), T = Temperature (°C), BWΔ = Body Weight change (g/d), ERf = Energy Retained as fat (kcal), ERp = Energy Retained as protein (kcal); ECE = Energy Content of Eggs (kcal/g) and EM = Egg Mass (g).
  C. Salas , R.D. Ekmay , J. England , S. Cerrate and C.N. Coon
  Traditionally, body composition data for poultry is determined by grinding /homogenizing the whole bird and obtaining a sample for wet chemistry analysis. The overall process is slow, requires a large amount of freezer space and the time-lag required for determining body composition reduces the opportunity to use data in real- time situations. Two studies were conducted to evaluate Dual-energy X-ray Absorptiometry (DEXA) as a means of measuring body composition in broilers and broiler breeders. In Trial 1, two hundred and forty Cobb 500 broilers were reared from day-old to 60 days of age. Broilers were extracted from the flock every 3 days during the 60 day grow-out in order to obtain a variety of body weights and body composition for developing the body composition equations. The birds were weighed and scanned using the small animal software mode of the DEXA scanner (LunarProdigy, GE®). DEXA provides measurements in grams of Bone Mineral Content (BMC), Fat Mass (FM) and Lean Mass (LM). It was assumed that the sum of BMC+FM+LM represented the total body mass. After the scan was performed, the carcasses were frozen for further chemical analysis. Prior to chemical analysis, the carcasses were thawed, autoclaved at 110°C with 1 atm pressure for 1-5 h depending upon Body Weight (BW) and homogenized in a heavy duty blender (Waring Laboratory, Blender LBC15, Model CB15). Samples of the homogenized carcasses were freeze dried, weighed, ground and analyzed for total ash, ether extract and crude protein. The measurements obtained from the DEXA scans were compared with the whole body chemical analysis for each broiler. Regression analysis of DEXA values (BMC, FM, LM) and chemical analysis (ash, ether extract and protein) were utilized to determine possible correlations. Prediction equations were then developed to adjust the original DEXA results to more accurately predict BMC, fat tissue and lean mass. The R2 values for the prediction equations using DEXA values were 0.999, 0.99, 0.96 and 0.99 for total mass, BMC, fat and lean mass (P<0.0001). In Trial 2, 156 Cobb 500 broiler breeder hens were scanned to validate the equations developed in Trial 1. The results indicate that the prediction equations were adequate and a reliable alternative for measuring body composition in broilers and broiler breeders. The high degree of correlation for all the variables indicates that with proper calibration the DEXA values can be used to predict body composition for these birds (R2 = 0.99, 9.99, 0.84 and 0.94 for total mass, BMC, FM and LM, respectively, p<0.001).
  C. Salas , R. Ekmay , J. England , S. Cerrate and C.N. Coon
  Cotton seed meal (CSM) is an alternative ingredient in poultry diets but its use is limited due to the presence of gossypol and the potential effects of gossypol on digestibility of nutrients. Glandless cottonseed is available and contains very low gossypol but there has been a limited amount of poultry nutritional studies completed with glandless cottonseed meal (GCSM). The TMEn, proximate analysis, amino acid content and amino acid (AA) digestibility of a glandless (GCSM) and a commercial (CCSM) cottonseed meal were determined with broilers. Thirty 42-day old Cobb 500 male broilers were precision-fed 30g of CCSM, GCSM and glucose and excreta collected during a 48 h period. Glucose was fed to serve as a control (no nitrogen or AA content). The chemical composition, gossypol content, True metabolizable energy (TMEn) and digestibility coefficients for AA were calculated for both meals. The crude protein and fat content of GCSM was higher than the CCSM (54 and 51%, 6 and 2%, respectively). Both meals were similar in calcium, total phosphorus and phytic acid contents. The CCSM had a higher content of total and free gossypol (1.52 and 0.161%, respectively) when compared to GCSM (0.02 and .003%, respectively). The TMEn for the GCSM provided approximately one thousand kcal more per energy/ kg than the CCSM. The essential AA content (g/kg; 90% DM) was determined for both cottonseed meals and was generally higher for GCSM compared to CCSM but both types of CSM contained higher levels of key essential AA than reported values for AA in the literature. The most extreme differences were for methionine and cystine; % methionine content was approximately 2 fold higher than values in the literature and the % cystine was 74 to 93% higher. The true digestibility coefficients for essential AA ranged from the low of 73.9% for isoleucine to 91.8% for arginine, for CCSM; the amino acid digestibility coefficients for GCSM were all higher than 90% for the essential AAs.
  M.J. Schlumbohm , R. Kriseldi , J.A. England and C.N. Coon
  A continual concern in poultry nutrition is the negative effects that mycotoxins have on animal performance when contaminated grain is used as a dietary ingredient. Mycotoxin binders have been available for decades and are used in the feed as an effective approach to decreasing the intestinal absorption of several mycotoxins, especially when present in low dietary concentrations. The research reported herein with broiler breeders was conducted to test the safety of an effective mycotoxin binder, Improved Milbond-TX® (IMTX), when added to the diet in concentrations higher than the 0.25% which is recommended by the manufacturer. Beginning at 21 weeks of age a typical corn-soybean meal diet was supplemented with IMTX at concentrations of 0, 0.5 and 1.0%. These three dietary treatments were fed continuously from 21 to 35 weeks of age to 300 broiler breeder hens. Data were collected on egg production, egg weights, hatchability, fertility and chick weights from 24 to 35 weeks of age. Egg production, expressed as eggs per hen housed, was not significantly different (p>0.05) among the three dietary treatments. Also, no significant differences (p>0.05) were found among the dietary treatments for egg weights, hatchability, fertility and chick weights. Results from this study show that an accidental over-supplementation of a broiler breeder diet resulting in up to 4 times the recommended dietary concentration of IMTX is not expected to result in any negative effect on broiler breeder performance or of the weight of chicks at hatch.
  J.A. England , J.R. Moyle , D.E. Yoho , R.K. Bramwell , R.D. Ekmay , R. Kriseldi and C.N. Coon
  The effect of pullet growth curve on body conformation and subsequent reproductive performance and effect of breeder feed protein level on reproductive performance was determined. The cost effectiveness of the different programs was evaluated. Cobb 700e pullets were reared from day of age in floor pens. Each pen was assigned to one of two growth curves from 16 weeks of age to housing at 21 weeks of age. One growth curve followed a standard (SD) body weight curve and a second followed a lighter (LI) body weight curve. At 23 weeks of age, half of the hens from each of the growth curves were assigned to one of two breeder diets. Half of the hens were fed a low (LO)-protein (14%) breeder diet and half were fed a higher (HI)-protein breeder diet (16%) during the production phase. Pullet growth curve significantly affected body weight through 30 weeks of age. The protein level of the breeder feed significantly affected body weight at 35 and 40 weeks of age. Pullet growth curve affected body conformation, but did not affect age of first egg. Pullet growth curve did not affect egg weight. Protein level of the breeder feed significantly affected egg weight; hens fed the HI-protein diet laid heavier eggs. Egg production was not affected by pullet rearing growth curve (p = 0.0845) or protein level (p = 0.7348) of the breeder feed. Feeding a LO-protein diet resulted in feed cost savings. The feed cost of SD reared hens fed LO-protein diet was $0.03227 per hen less than for those fed HI-protein diets. The feed cost of LI reared hens fed LO-protein diet was $0.3616 per hen less than for those fed HI-protein diet.
  J.V. Caldas , M.A. Sabir , M. Putsakum , J.A. England and C.N. Coon
  Background: Live coccidiosis vaccines given to broilers at hatch generally decrease body weight gain during the early feeding phases but the effect could reverse after the development of immunity. This study intended to determine if diets supplemented with exogenous protease and carbohydrases can improve Body Weight Gain (BWG) and Feed Conversion Ratio (FCR) after coccidia infection. Methodology: Two thousand three hundred and four male chicks were randomly divided into six diets: Negative Control (NC), Positive Control (PC) and 4 multi-enzyme composites (MEC), all enzyme diets had protease but different carbohydrase combinations for 42 days study. The ANOVA test was utilized. Results: Three different MEC decreased the E. coli population in the ileum. Diets with MEC provided an additional apparent metabolizable energy corrected by nitrogen (AMEn) from 91-236 kcal kg–1 compared to the NC and improved digestibility of Amino Acids (AA) from 0.86-5.53% for 3 of the MEC. Cystine, threonine and serine digestibility were each increased >2.8% with MEC compared to the NC. Proteins in mucins contain high quantities of these AA, so enzymes may be providing more of these AA. The FCR for NC broilers was worse than PC (p≤0.05). The FCR, tended to be improved with three of the MEC, however one composite did not achieve better FCR. Conclusion: The MEC improved nutrient utilization with tendency to improve FCR. However, more time may be required to achieve compensatory BWG using MEC with a coccidia infection. The present study also opens the door to study the interaction of MEC and microflora population in the gastrointestinal tract of chickens.
  T. Cao , J.T. Weil , P. Maharjan , J. Lu and C.N. Coon
  Background and Objective: The requirement of sulfur amino acids for laying hens have been determined but the method in which methionine is regulated has not been studied. The aim of this research was to study the hepatic methionine-metabolizing enzymes and metabolites in laying hens. Materials and Methods: Five hundred forty Dekalb-XL laying hens were housed and fed a control diet until sampling. On day of sampling, six hens were sacrificed at each time period to allow for determination of hepatic enzymatic activities and metabolite concentrations during light and dark periods. Data was analyzed using the general linear models (GLM) procedure with statistical analysis software (SAS). Results: The enzymes and metabolites showed cyclical changes related to light and dark periods. During the light period of the day, layers showed elevated activities of methionine s-adenosyltransferase (EC; MAT), cystathionine ß-synthase (EC; CS) and cystathionase (EC; C-ase) and depressed activities of betaine-homocysteine methyltransferase (EC; BHMT) and N5methyltetrahydrofolate-homocysteine methyltransferase (EC; MFMT), as compared to the dark period of the day. The hens also had a decreased methionine to cysteine ratio (Met/Cys ratio), an increased methylation ratio (s-adenosylmethionine to s-adenosylhomocysteine ratio; SAM/SAH ratio) and an increased cystathionine (CYST) concentration in the liver during the light period. Conclusion: The changes of the enzymatic activities and metabolite concentrations suggest that the methionine metabolism of laying hens during the light period was in favor of methionine degradation through cysteine synthesis. Alternatively, the metabolism of hens during the dark period was in favor of methionine conservation by limiting the conversion of methionine to cysteine. Thus, feeding hens a higher cysteine diet several hours before lights are turned off may prove beneficial to counteract the limited cysteine synthesis from dietary methionine during the dark period of the day.
  T. Cao , J.T. Weil , P. Maharjan , J. Lu and C.N. Coon
  Background and Objective: Two experiments were conducted to determine the total sulfur amino acid requirements in laying hens. The objective of Experiment 1 was to determine the digestible methionine and cystine requirements for laying hens. An additional experiment (Experiment 2) was conducted to determine the cystine requirement for laying hens and determine the utilization efficiencies of supplemental methionine and cystine to meet the cystine requirement. Materials and Methods: In Experiment 1, one hundred and seventy-six laying hens were randomly assigned into 11 dietary treatments for a six-week period. One group of hens received a corn-soybean meal control diet containing 2,899 kcal ME kg1 and 19.5% CP, while the remaining ten groups of hens received 10 test diets containing 2,850 kcal ME kg1 and 15% CP. Five diets were deficient in cystine (0.148% digestible cystine), containing digestible methionine levels of 0.143, 0.240, 0.337, 0.434 and 0.531% and another five diets were excessive in cystine (0.450% digestible cystine), containing digestible methionine levels of 0.143, 0.231, 0.317, 0.407 and 0.495%. An additional experiment (Experiment 2) was conducted by assigning one hundred sixty laying hens to one of two series of diets, which were formulated to contain 0.319% digestible methionine and 0.148% digestible cystine, same as that in Experiment 1, with exception of the methionine level. Four levels of equimolar amounts of methionine or cysteine (½ cystine) were added to the basal diet. The added levels were 0.05, 0.10, 0.15 and 0.20% for methionine and 0.04, 0.08, 0.12 and 0.16% for cystine since the molecular weight of cysteine (½ cystine) is 80% of that of methionine. Data generated from each experiment was analyzed using the general linear models (GLM) and analysis of variance procedures with the help of statistical analysis software (SAS). A second-order polynomial regression analysis was conducted in order to determine the methionine requirements for laying hens. Results: The results showed that the requirement of digestible methionine and digestible cysteine for laying hens were 354 and 184 mg hen1 day1 for egg mass (EM), 349 and 193 mg hen1 day1 for feed conversion, 437 and 325 mg hen1 day1 for body weight change (BWC) and 367 and 189 mg hen1 day1 for EM+BWC, respectively. Deficient or excessive dietary methionine produced an increase of methionine degradation due to the increased body weight loss or the excessive dietary methionine, correspondingly. Optimum dietary methionine levels resulted in increased liver SAM/SAH concentration ratios (s-adenosylmethionine/s-adenosylhomocysteine) and decreased homocysteine (Hcy) levels. Conclusion: The results demonstrated that the utilization efficiencies of methionine and cysteine (½ cystine) were 100% on an equimolar basis for egg mass and 90% on an equimolar basis to prevent loss of body weight. When methionine was used to meet the cystine requirement, an utilization efficiency of 80% was adequate on a weight and concentration basis for egg mass and 72% for body weight maintenance. The practice of feeding ingredients with a substantial digestible cystine level for supporting body weight may be beneficial for laying hens.
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