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Articles by C. Salas
Total Records ( 6 ) for C. Salas
  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.
  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.
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