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The use of non-linear regression models in the analysis of biological data has led to advances in poultry nutrition. Spline or broken-line nonlinear regression models are commonly used to estimate nutritional requirements. One particular application of broken-line models is estimating the maximum safe level (MSL) of feed ingredients beyond which the ingredients become toxic, resulting in reduced performance. The objectives of this study were to evaluate the effectiveness of broken-line models (broken-line linear or BLL; and broken-line quadratic or BLQ) in estimating the MSL; to identify the most efficient design of feeding trials by finding the optimal number of ingredient levels and replications; and to re-estimate the MSL of various test ingredients reported in the nutrition literature for comparison purposes. The Maximum Ingredient level OptimizationWorkbook (MIOW) was developed to simulate a series of experiments and estimate the MSL and the corresponding descriptive statistics (SD, SE, CI, and R2). The results showed that the broken-line models provided good estimates of the MSL (small SE and high R2) with the BLL model producing higher MSL values as compared to the BLQ model. Increasing the number of experimental replications or ingredient levels (independently of each other) reduced the SE of the MSL with diminishing returns. The SE of the MSL was reduced with increasing the size (total pens) of the simulated experiments by increasing either the number of replications or levels or both. The evaluation of MSLs reported in the existing literature revealed that the multiple range procedure used to determine the MSL in several reports can both overestimate and underestimate the MSL compared to the results obtained by the broken-line models. The results suggest that the broken-line linear models can be used in lieu of the multiple range test to estimate the MSL of feed ingredients along with the corresponding descriptive statistics, such as the SE of the MSL. [ABSTRACT FROM AUTHOR]

Crude protein in corn and soybean meal have been documented to vary, and such inherent variability can result in under- or over-feeding of CP when feeds are formulated, leading to reduced bird growth, added input costs, and increased environmental pollution. The purpose of this study was to compare 2 grain-handling techniques and 2 feed formulation methods (linear vs. stochastic programming) to reduce CP variability in finished feeds and determine resulting costs or savings. The 2 grain-handling techniques were placing all the random batches of each delivered ingredient in to (1) a single bin (1-bin method) or (2) segregating above- and below-average samples into 2 bins (2-bin method). A fast way of estimating the composition of the ingredients is now available (near-infrared reflectance spectroscopy). Microsoft Excel workbooks were constructed to solve broiler starter feed formulation problems. Formulating feeds by linear and stochastic models based on the 2-bin method reduced CP variability by at least 50% compared with the 1-bin method. Formula cost was reduced by ~20 cents per ton (averages of August 2012 United States ingredient prices) when the 2-bin method was used with the linear model. Formulating feed with a margin of safety increased formula cost by $3.40 per ton. Stochastic feed formulation increased formula cost to meet the specified CP level in feed at any probability of success, and formula cost was reduced substantially with the 2-bin method (up to $6.47 per ton). The magnitude of savings and reduced feed variability suggested that, regardless of the costs associated with building extra bins, the 2-bin method can be economically efficient in the long run. Therefore, it could be possible to split the batches of feed ingredients at a feed mill into above- or below-average bins before feed formulation to reduce CP variability and to maximize savings. [ABSTRACT FROM PUBLISHER]

Researchers often seem to choose the number of birds per pen and replications per treatment somewhat arbitrarily on the basis of cost, availability of animals, housing considerations, convenience, tradition, and so on. Statistical simulation, performed while designing an experiment, will provide a researcher with an objective estimate of the number of birds per pen and replicates needed for an experiment of known Type I and II errors. In most cases, the time for making power calculations should be before, not after, an experiment is conducted. Here we present a Microsoft Excel workbook to explore the statistical and economic ramifications of different combinations of birds per replicate and replicates per treatment for research with poultry. [ABSTRACT FROM AUTHOR]

Persons conducting research trials often want to be able to declare that treatments, or particularly products, are equivalent (will provide indistinguishable results). However, all research trials can ever provide is the probability that the observed differences in an experiment were due to chance. Also, in trials in which variances are high and there are few replications, it is quite easy to declare no significant differences and equivalency. This paper describes a Microsoft Excel spreadsheet that can be used to easily construct experimental power curves. Such curves predict the proportion of experiments that would yield a given level of significance as the difference between the 2 means increases. The spreadsheet uses the mean and variances from an experiment with the Norm.inv and Rand functions of Excel to simulate outcomes from identical experiments. An experiment that declared GMO and normal feed ingredients to be equivalent was used to illustrate the application of power curves. The experiment had 12 replicate pens of broilers per treatment. The outcomes of 90,000 simulated experiments, each with the same overall variance, but 0 through 8 percent differences in treatment means, were graphed. When the published experiment purported to show equivalence, really it showed that a significant difference in growth (P < 0.05) would be expected to be detected 50% of the time if the means were different by 3.1%; a difference of 4.6% in treatment means could be detected 80% of the time by such an experiment. This Excel spreadsheet enables such a power analysis to be conducted. Easy modifications of the spreadsheet can illustrate the influence of changing the variance or number of replications on the expected power of future experiments. The economic impact of small changes in performance is also discussed. [ABSTRACT FROM AUTHOR]

Manipulating the development of the leg bone by making simple changes to incubation temperature could help reduce the incidence of abnormalities. This study tested the hypothesis that increasing or decreasing the temperature of chick incubation by 1°C for 3 d during ED 4 to 7 affects hatchability, growth, and leg abnormalities of Cobb 500 broilers fed 3 diets: a diet that induced tibial dyschondroplasia, a Ca-deficient diet that induced rickets, and a P-deficient diet that induced rickets. In experiment 1, eggs hatched earlier, and more eggs hatched, at 38.5°C (92.77%) compared with at 37.5°C (86.22%). Body weight was lower in chicks incubated at the higher temperature compared with those incubated at the lower temperature (44.66 vs. 42.92 g). In experiment 2, egg setting times were +17 h for 36.5°C eggs and -10 h for 38.5°C compared with standard setting at 37.5°C (508 h). Hatchability of fertile eggs (92.92%) was highest at 37.5°C and decreased at 36.5°C (89.82%) and 38.5°C (81.55%). Body weight was lower (48.98 g) at 36.5°C than at 37.5°C (49.57 g) and at 38.5°C (50.56 g). Experiment 3 separated effects of incubation temperature and incubation time and was conducted with control and Ca-deficient diets. No main effects or interactions between incubation temperature or time and bone abnormalities were detected. It is important to note that eggs hatched at different times in this study. A difference as little as 1°C for 3 d during ED 4 to 7 affected hatching time and weight. [ABSTRACT FROM AUTHOR]

The effects of graded levels of corn distillers dried grains with solubles (DDGS) were investigated as a partial replacement for sources of protein, energy, and other nutrients for broilers when the digestible amino acid balance was maintained. Zero, 8, 16, and 24% DDGS were incorporated into isonutritive diets at the expense of corn, soybean meal, and DL-Met. Poultry oil, L-Lys, and L-Thr additions increased with increasing levels of DDGS. Diets were each fed to 36 Cobb 500 straight-run broilers in 6 floor pens in 2 experiments. In experiment 1, broilers fec ⩽ 8% DDGS showed increased BW gain compared with those fed the control diet during the 0to 18-d starter period (P = 0.0164) but were almost identical in BW at 42 d (P = 0.9395). The only difference at 42 d was in the carcass fat composition of female broilers: percentage of fat pad decreased with increasing DDGS level (P = 0.0133). Corn DDGS reduced the pellet durability index. However, the pellet durability index was not related to growth or feed utilization. In experiment 2 at 42 d, broilers fed all levels of DDGS showed increased BW gain compared with those fed the control diet. Broilers may perform well when fed properly balanced feeds containing up to 24% DDGS despite reduced pellet quality. [ABSTRACT FROM AUTHOR]

Methionine is the first-limiting amino acid in corn and soybean meal-based poultry diets. Therefore, its supplementation level is of primary economic importance to poultry production. The responses to the methionine sources DL-methionine (DLM) and methionine-hydroxy analog-free acid (HMTBA) have been compared using various methodologies. The so-called common plateau nonlinear model has been used to estimate relative bioavailabilities of the sources. This model has a coefficient that is used as a single value to compare the relative bioavailabilities of the sources for independent technical parameters like gain and feed efficiency. This model was used previously in a meta-analysis of published experiments, and 79 and 81% relative biological efficiencies of HMTBA were found for DLM for ADG and feed utilization efficiency, respectively. Because different sources would have different optimal feeding levels to maximize profits, we demonstrate the challenge of calculating a single optimal level for the different methionine sources. Further, we apply an economic analysis to results of the previous meta-analysis to demonstrate that the relative values of HMTBA and DLM for BW and ADG are between 81 and 86%, depending on the value of a broiler and the costs of feed and DLM. [ABSTRACT FROM AUTHOR]

A random-mating population was used to study .the genetic interrelationship between phytate P (PPB), Ca (CaB), N (NB), and energy bioavailability (EB), BW at 4 wk of age, relative growth (RG), and feed conversion ratio (FCR). Heritability estimates for PPB, CaB, NB, and EB were 0.09, 0.13, 0.16, and 0.10, respectively, and those of BW, RG, and FCR were 0.66, 0.15, and 0.10, respectively. Genetic correlations between PPB and BW, and FCR were moderate and negative, suggesting that improvement in PPB will impair growth. The genetic correlations between PPB and CaB, and EB and RG were positive and moderate, indicating that improvement in PPB would also lead to improved CaB, EB, and RG. Energy bioavailability was positively correlated with CaB, NB, PPB, and BW. Even though the genetic correlation between EB and the other traits measured, except RG and FCR, ranged from low to moderate, improving the ability of birds to utilize caloric energy in the feed would consequently improve PPB as well as growth. Improving PPB would reduce the amount of P in excreta and provide an additional savings if exogenous phytase were not added to poultry feed. The genetic correlation between PPB and NB was low but positive, whereas NB had a positive genetic correlation with BW. Therefore, selecting on NB will result in positive correlated responses in BW and PPB. Improving PPB and NB will not only improve productivity, but also reduce the polluting effects of P and N on the environment. [ABSTRACT FROM AUTHOR]

Supplementation of 1α-hydroxycholecalciferol (1α-OHD3), phytase, and Ca levels has been shown to influence phytate P utilization. Two experiments were conducted with 1- to 16-d broilers to investigate the interactions between the effects of 1α-OHD3, phytase, and Ca on phytate P utilization. In experiment 1, the birds were randomly allocated to 13 treatments with 6 levels of 1α-OHD3 from 0 to 11μg/kg, with and without 500 U/kg of phytase supplemented to P-deficient diet. A positive control diet, adequate in Ca and P, was included. In experiment 2, a 3-dimensional rotatable design with 5 levels each of 1α-OHD3, phytase, and Ca was implemented. Supplementation of 1α-OHD3 and phytase increased phytate P utilization, as indicated by an increase in bone ash, phytate P disappearance, and BW. In experiment 1, no interaction between the 1α-OHD3 and phytase effects was determined for any criteria, except for the incidence of P rickets. However, the second experiment showed that there were interactions between the 3 factors (1α-OHD3, phytase, and Ca). The probabilities that observed variation in the 3-way interaction for measured criteria that were clue to chance are: BW gain 0.1364, G:F = 0.11, bone ash percentage = 0.0278, milligrams of bone ash/tibia = 0.0909, Ca rickets = 0.9394, P rickets = 0.4892, tibial dyschondroplasia = 0.5927, and phytate P disappearance = 0.1126. The equations obtained from the regression models were used to generate contour-surface plots. The percentage of bone ash data indicated that low Ca, high phytase, and high 1α-OHD3 levels were needed to optimize phytate P utilization. The results of this study show that this experimental design may be utilized to identify the best levels of nutrients to add to a diet where complex 3-way interactions exist affecting several criteria. The equations may be used to optimize performance based on desired levels of performance and the costs of the inputs. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine that variation in broiler P utilization is due to breeder age and egg storage time. Experiment 1 was conducted with chicks hatched from eggs laid by Ross x Ross 308 breeders (27 vs. 61 wk old) and stored for 0 or 10 d. The age of breeders had significant effects (P < 0.05) on 0 to 16 d chick growth (379 ± 18 vs. 308 ± 19 for 27- and 61-wk-old breeders, respectively). The longer egg storage time of chicks from older breeders resulted in higher P rickets scores and incidence, but longer egg storage time of chicks from younger breeders resulted in lower P rickets score and incidence (significant interaction, P = 0.0455). The longer egg storage time of chicks from older breeders resulted in lower bone ash (%), and the longer egg storage time of chicks from younger breeders resulted in higher bone ash (%). Experiment 2 was conducted with chicks hatched from eggs laid by Ross x Ross 308 breeders (26 vs. 60 wk old) and stored for 0 or 10 d. The diets were P deficient and with or without 5 μg/g of 1α-OH cholecalciferol 1α-OH vitamin D3). Breeder age had significant effects (P = 0.0003) on 0 to 16 d chick growth (272 ± 7 vs. 339 ± 8 for 26- and 60-wk-old breeders, respectively) and chick mortality (P = 0.0134). The P rickets score increased with breeder age (P = 0.0186) and egg storage time (P = 0.1057). The factors influencing the incidence of P rickets in broilers should include breeder age and egg storage time as well as genetics and dietary levels of Ca, P, and vitamin D activity of the P-deficient diets. [ABSTRACT FROM AUTHOR]

There is considerable data on the effect of reducing inorganic Ca and P in broiler finisher diets on carcass quality. However, there is limited information on the effect of reducing dietary Ca and P during the different phases of growout. Two experiments were conducted from 0 to 35 d in floor pens. In both experiments, at least 4 replicates per treatment (50 chicks per replicate) were used. Corn-soybean meal and soybean oil-based diets deficient in Ca and P were fed. During the starter phase (ST), from 0 to 18 d, chicks were fed a 23% CP diet containing 0.60% Ca and 0.47% total P (tP). During the grower-finisher phase (GF), from 19 to 35 d, birds were fed a 19% CP diet containing 0.30% Ca and 0.37% tP. A combination of 1,000 phytase units/kg of Natuphos phytase and 5 µg/kg of la-hydroxycholecalciferol (P + la) was supplemented to some of the feed during the ST and GF. Diets containing adequate Ca and P were also fed during the ST (0.90% Ca and 0.68% tP) and GF (0.80% Ca and 0.67% tP). The level of tibia ash and the incidence of bone disease were measured at 18 and 35 d. At the end of the experiments, birds were processed and evaluated for muscle hemorrhages and broken bones. In both experiments, broilers fed diets that were not P + 1α supplemented demonstrated poor bone mineralization, considerable leg problems, and a high incidence of broken bones after processing. Broilers fed P + 1α throughout had more broken clavicles and femurs compared with birds fed the adequate diets. Day-18 tibia ash was significantly correlated to broken tibias and femurs during processing. Day-35 tibia ash was better correlated to bloody breast meat than to broken bones. It is concluded that carcass quality depends on the levels of Ca and P fed and the age of the bird. Tibia ash, traditionally used as an indication of bone strength, was better correlated to the incidence of bloody breasts. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine if a 3-way interaction among genotype, dietary lysine, and CF is an important influence on dietary responses. The genotypes were Ross 308 and Cobb in experiment 1 and Ross 508 and Arbor Acres Classic in experiment 2. The experimental designs were completely randomized with an incomplete 2 × 2 × 3 factorial arrangement of treatments. On d 7 of experiment 1, 4 replicate pens of 6 chicks each were fed 1 combination of dietary lysine and CP (17% CF with 0.6, 0.7, and 0.8% lysine and 23% CF with 0.7, 0.8, and 0.9% lysine) until d 21. On d 17 of experiment 2, 4 replicate pens of 35 chicks each were fed 1 combination of dietary lysine and CF (17% CF with 0.7, 0.8, and 0.9% lysine and 23% CP with 0.8, 0.9, and 1.0% lysine) until d 42. On d 43 of experiment 2, 3 birds per pen were processed. Regression analysis showed differences (P < 0.05) due to genotype for body weight gain (BWG), feed intake, and feed conversion ratio (FCR) in experiment 1, and BWG, carcass yield, breast fillet and tender yields, and abdominal fat pad percentage in experiment 2. Increasing dietary CP decreased abdominal fat pad percentage in both experiments; however, increasing dietary lysine only decreased this parameter in the starter-phase chicks. In both experiments, Ross broilers had a greater response to supplemental lysine when 17% CP was fed, but less response to supplemental lysine when 23% CP was fed for both BWG and FCR (3- way interaction). Three-way interactions between dietary CP and lysine levels and genotype were observed for BWG (P < 0.01), feed intake (P < 0.01), and FCR (P < 0.02) in experiment 1 and for feed intake (P < 0.06) and FCR (P <0.03) in experiment 2. The 3-way interactions demonstrate that quantitative differences exist between genotypes in response to increasing dietary levels of CP and lysine. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to examine the calcium requirements of broiler chickens fed corn-soybean meal diets. Experiment 1 used a 6 × 2 × 2 factorial arrangement and was conducted with broilers in floor pens during the grower phase (19 to 42 d). Diets were mixed with 6 levels of dietary Ca (0.325, 0.4, 0.475, 0.55, 0.625, and 0.9%) and 17 or 23% CP and fed to males and females separately. Experiment 2 was a 6 × 2 factorial design conducted using Petersime battery brooders during the starter phase (0 to 16 d). The same 6 levels of dietary Ca used in experiment 1 were fed separately to each sex, but only at the 23% level of CP. The diets used in both experiments were formulated to contain 0.45% nonphytin phosphorus. In experiment 1, grower chickens did not demonstrate significant body weight gain (BWG) or feed conversion ratio (FCR) response (g of feed per g of gain) to the different levels of Ca at either level of protein. The percentage tibia ash did not respond to increasing Ca levels beyond 0.625% Ca at either protein level. In experiment 2, BWG increased linearly up to 0.55 and 0.625% dietary Ca for males and females, respectively. Feed conversion ratio decreased linearly with increasing dietary Ca up to 0.625% Ca, and tibia ash was highest at 0.9% Ca for both sexes. These results suggest that the current NRC Ca requirements for the broiler starter (1.0%) are sufficient for maximum bone ash, but that Ca requirements for grower birds (0.9%) may be excessive for optimum BWG, FCR, and tibia ash. [ABSTRACT FROM AUTHOR]

Supplemental 1α-hydroxycholecalciferol (1α-OHD3) has been shown to have qualitatively similar and quantitatively additive effects to exogenous phytase. Two experiments were conducted from 0 to 35 d in floor pens to determine the additive effect of phytase and 1αOHD3 when supplemented to Ca- and P-deficient diets. In both experiments, at least 4 replicates per treatment (50 chicks per replicate) were used. Corn-soybean-meal- and soybean-oil-based diets were fed and birds were raised in a house impervious to ultraviolet light. During the starter phase (ST), from 0 to 18 d, chicks were fed a 23% CP diet containing 0.60% Ca and 0.47% total P (tP). During the grower/finisher phase (GF), from 19 to 35 d, birds were fed a 19% CP diet containing 0.30% Ca and 0.37% tP. A combination of 1,000 phytase units/kg of Natuphos phytase and 5 µg/kg of 1α-OHD3 (P+1A) was supplemented to some of the feed during the ST and GF. Diets containing adequate Ca and P were also fed during the ST (0.90% Ca, 0.68% tP) and GF (0.80% Ca, 0.67% tP). Performance characteristics and the incidence of rickets and tibial dyschondroplasia were measured at 18 and 35 d. In experiment 1, unsupplemented chicks performed well but had considerable leg problems. Chicks fed P+1A during the ST or GF did not perform as well as birds fed P+1A throughout. Birds fed P+1A throughout performed as well birds fed the adequate diets without any indication of leg problems. In experiment 2, unsupplemented birds performed similarly to unsupplemented birds in experiment 1. However, chicks fed the supplements or the control diets did not perform as well or accumulate as much bone ash as birds in experiment 1, although the diets were formulated identically in both experiments. Diets with as little as 0.30% Ca and 0.37% tP appear to be adequate for broilers older than 18 d if supplemented with the correct amounts of phytase and 1α-OHD3. However, there are unknown variables that may limit the potential of broilers in terms of bone mineralization and bone pathology, even when adequate diets are fed. [ABSTRACT FROM AUTHOR]

Phytase supplementation over a range of different levels of dietary Ca and nonphytate phosphorus (NPP) was investigated by comparing surface response curves from regression equations generated with (experiment 1) and without (experiment 2) phytase using various performance and bone quality parameters. Cobb × Cobb broiler chicks were raised from 0 to 16 d in 2 experiments using corn-soybean meal based diets. Experiment 1 used a 4 × 4 factorial arrangement with diets formulated to contain combinations of 4 levels of Ca: 0.38, 0.58, 0.78, and 0.98% and 4 levels of NPP: 0.2, 0.3, 0.4, and 0.5%. Experiment 2 used a composite rotatable design in which rations were formulated to contain dietary Ca levels of 0.38, 0.47, 0.68, 0.89, and 0.98% and NPP levels of 0.20, 0.24, 0.35, 0.46, and 0.50%. An extra point was included in the design to contain the lowest Ca and lowest NPP levels (0.38% Ca and 0.20% NPP). All combinations of Ca and NPP were fed with 657 phytase units/kg Natuphos 5000 phytase, plus 4 combinations (0.38% Ca and 0.20% NPP, 0.47% Ca and 0.24% NPP, 0.68% Ca and 0.35% NPP, and 0.89% Ca and 0.46% NPP) were fed without phytase to determine the suitability of comparing multiple regression response surfaces for particular variables among experiments. Comparison of surfaces, with and without phytase, showed that growth and bone quality responses to phytase were greatest at low NPP levels and high Ca levels, and these decreased when the Ca level was reduced or when the NPP level was increased. A third experiment confirmed that phytase elicits a greater response at higher Ca levels and lower NPP levels (0.86% Ca and 0.20% NPP) versus low Ca levels and low NPP levels (0.47% Ca and 0.24% NPP). The data demonstrated why it is impossible to determine a single NPP equivalency value for phytase supplements. [ABSTRACT FROM AUTHOR]

An experiment was conducted with broiler breeder hens to determine the relative biological value of 25-hydroxycholecalciferol (25-OHD3) compared with cholecalciferol (vitamin D3) for hen-day egg production, hatchability, embryo mortality (early, 1 to 10 d of incubation, late, 11 to 21 d), and body ash of the progeny. The study was conducted with 73-to-90-wk-old molted Ross broiler breeder hens in an environment excluding ultraviolet light. A basal vitamin D3 deficient diet supplemented with 4 levels of vitamin D3 (0, 3,125, 12,500, and 50,000 ng/kg of diet) and 2 levels of 25-OHD3 (3,125 and 12,500 ng/kg of diet) was fed. The relative biological values of 25-OHD3 in comparison to vitamin D3, using slope ratio techniques, were 138, 133, 128, and 111% for hen-day egg production, hatchability, late embryo mortality, and body ash of the progeny, respectively (average = 128%). When comparing 25-OHD3 against D3 at the 3,125 ng/kg level, the relative biological values were 209, 167, 400, and 108% for the same criteria, respectively (average = 221%). However, at the 12,500 ng/kg level no statistical differences between 25-OHD3 and D3 were observed (average = 108%). Four trials were conducted to determine the effect of the maternal diet on the performance and leg abnormalities of the hens' progeny. In experiment 1, no vitamin D was added to the corn-soybean meal basal diet fed to the chicks, and in experiments 2, 3, and 4 the basal diet was supplemented with 27.5 µg of D3/kg of diet. In the progeny study, the average relative biological value of 25-OHD3 at the 3,125 and 12,500 ng/kg levels were 115 and 101%, respectively. The potency of 25-OHD3 in relation to vitamin D3 depended on the level tested. When comparing vitamin D sources, 25-OHD3 had greater potency than D3 only at very low levels of supplementation. [ABSTRACT FROM AUTHOR]

Databases comparing total amino acid (AA) profiles and standardized ileal AA digestibility (SID) values of 20 feedstuff's commonly fed to pigs from two sources, Evonik (Kennesaw. GA) and the Nutrient Requirements of Swine published by the National Research Council (NRC; Washington, DC) were used to observe AA concentration effects on digestibility values. Both databases reported SID swine values. The number of AA values depends on the ingredient. The 20 feed ingredients were compared from each database and were analyzed using PROC CORR and GLM procedures of SAS (version 9.4; SAS Inst. Inc., Cary, NC). When both databases were compared in their entirety, there was a positive correlation of 0.362 for the Evonik database and 0.349 for the NRC database (P < 0.0001) with increasing total amino acids vs. SID digestibility. There were also differences between feed ingredients in the Evonik and NRC databases (P < 0.0001). There were differences in SID of animal and plant sources (P < 0.001). When only essential AA were compared, there were positive correlations of 0.353 and 0.455 for the Evonik and NRC databases, respectively (P < 0.0001), of total AA to SID digestibility. There was a trend for differences between plant and animal feed ingredients when essential AA were being compared (P < 0.10). Four essential AA were analyzed separately across feedstuff: Lys, Met, Trp, and Thr. Lysine in both databases had a correlation with increasing total lysine and increasing SID (0.556 and 0.618; P < 0.01) forthe Evonik and NRC databases, respectively. Methionine also had increasing SID with total AA with a correlation of 0.577 and 0.666 (P < 0.01) for the Evonik and NRC databases, respectively. Methionine also had differences in SID in plant vs. animal sources (P < 0.05). Tryptophan had a correlation of 0.435 (P < 0.06) for the Evonik database, while the NRC database had a correlation for Trp of 0.544 (P < 0.01) of increasing SID with increasing total Trp. Threonine had a correlation of 0.390 (P < 0.09) for the Evonik database and 0.505 (P < 0.05) for the NRC database of total Thr vs. Thr SID digestibility. From this data, a predictor of AA digestibility is AA concentration of the feedstuff. The digestibility of AA in the feedstuff should be a property of the feed ingredient and not the concentration of AA in the feed ingredient. Differences in databases will change the cost of diet formulation. The database that is used to formulate amino acid profiles could affect the performance of the pig because of differences between databases. [ABSTRACT FROM AUTHOR]

An abstract of the article "Evaluation of DDGS as an alternative ingredient for broiler chickens," by M.Y. Shim and colleagues are presented.

A series of 4 floor pen studies was conducted to evaluate the effects of environmental temperature modification on nicarbazin (NIC) responses in broiler chickens raised to 28 d of age. Birds were reared at either standard temperatures (recommended by the primary breeder for ages zero to 28 d) or at 3°C below this level. From placement to 28 d, birds were provided feeds containing zero, 100, or 125 ppm NIC, comprising a 2 × 3 factorial arrangement in each test. Two of the trials were conducted in the presence of an imposed coccidial challenge and 2 were conducted in healthy animals. At 18 and 28 d of age, performance was recorded; cloacal temperatures were measured at 7, 14, 21, and 26 days. Mortality data were collected daily and coccidial lesions were scored at 6 d post challenge. Results of these studies revealed that NIC improved coccidial lesion scores regardless of environmental temperature. In the absence of coccidial challenge, NIC depressed performance, but reductions in environmental temperature diminished the magnitude of these responses. Under conditions of coccidial challenge, NIC significantly improved body weight gains in both temperature environments. Compared to standard temperature conditions, lower environmental temperatures exerted a positive effect on feed conversion rates of NIC-fed broilers. Birds reared in the low temperature environment exhibited lower cloacal temperatures than standard environment groups throughout the test period. Irrespective of coccidial challenge, lower environmental temperatures significantly reduced nicarbazin mortality compared to standard temperature groups, resulting in a significant nicarbazin x temperature interaction. This finding indicates that temperature modification is a practical method for minimizing mortality over the course of 28-day nicarbazin usage. [ABSTRACT FROM AUTHOR]