Standardized Ileal Amino Acid Digestibility of Corn, Corn Distillers' Dried Grains with Solubles, Wheat Middlings, and Bakery By-Products in Broilers and Laying Hens.

Standardized ileal amino acid digestibility (SIAAD) of 5 samples of corn distillers dried grain with solubles (DDGS), 5 samples of bakery by-products (BBP), 3 samples of corn, and 1 sample of wheat middlings (WM) were evaluated in broilers and laying hens. Diets containing each of the 14 feed ingredients were evaluated in 21 day-old broiler chickens. The DDGS and BBP containing diets were fed to 30-week-old laying hens, while corn and wheat middling were evaluated in 50-week-old laying hens. All the diets were semi-purified with each feed ingredient being the only source of amino acid (AA). To obtain SIAAD values, apparent ileal AA digestibility was corrected for basal ileal endogenous AA losses using values generated from broilers and laying hens fed a nitrogen-free diet. Ileal crude protein digestibility for the 5 DDGS samples was higher (P < 0.05) in broilers than in laying hens. Broilers had higher SIAAD for DDGS 2, 3, 4, and 5 while there was no difference for DDGS 1 except for 4 AA where broilers had higher (P < 0.05) SIAAD values. Standardized ileal AA digestibility values for broilers were higher (P < 0.05) for BBP 1 and 4. Ileal CP digestibility for corn 1 was higher (P < 0.05) for broilers compared to laying hens, and SIAAD values for the 16 AA (9 indispensable and 7 dispensable) evaluated in this study were higher (P < 0.05) in broilers. Broilers had higher (P < 0.05) SIAAD values for 4 (histidine, leucine, phenylalanine, and valine) and 6 (histidine, leucine, methionine, phenylalanine, threonine, and valine) indispensable and 3 (cysteine, glutamic acid, and proline) and 4 (cysteine, glutamic acid, proline, and serine) dispensable AA for corn 2 and corn 3, respectively. No difference in SIAAD between broilers and laying hens was observed for WM. Results from this study confirm that high variability in digestibility exists between different samples of DDGS. Differences in SIAAD between broilers and laying hens were observed in some samples of DDGS and BBP.

Standardized ileal amino acid digestibility of meat and bone meal and soybean meal in laying hens and broilers.

The objective of this study was to determine the standardized ileal amino acid digestibility (SIAAD) of 7 meat and bone meal (MBM) and 3 soybean meal (SBM) samples in broilers (Ross 708) and laying hens (Hy-line W36). All 10 feed ingredients were evaluated in 21-d-old broiler chickens and 30- or 50-wk-old laying hens. Standardization was accomplished by correcting for basal ileal endogenous amino acid losses using a nitrogen-free diet. Broilers were reared in cages from d 0 to 16 on a standard broiler starter diet adequate in all nutrients and energy; thereafter, they were allotted to treatments using a randomized complete design with 6 replicate cages of 8 birds each. For the laying hens, 6 replicate cages of 6 birds each (542 cm(2)/bird) were used. Each treatment diet, which was fed for 5 d, was semipurified, with MBM or SBM being the sole source of amino acids in each diet. Ileal endogenous amino acid losses were not different between broilers and the 2 groups of laying hens. Meat and bone meal from different locations varied widely in digestibility. Broilers had higher (P < 0.05) SIAAD in 4 of the 7 MBM samples. In 2 of the 3 SBM samples, broilers had higher (P < 0.05) SIAAD for most of the nonessential amino acids. Generally, hens had 6.4 and 7.7% units less Met and Lys digestibility of all MBM samples after standardization. Dry matter digestibility values of the SBM samples were higher (P < 0.05) in broilers. Likewise, broilers had 4.1 and 1.5% units more Met and Lys digestibility of all the SBM samples evaluated compared with those from laying hens. The results of these experiments suggest that differences exist in the digestive capabilities of laying hens and broilers, which indicates that species-specific nutrient digestibility values or adjustments may be needed.

Ileal digestibility of amino acids in pea protein isolates, wheat-corn distillers dried grains with solubles, and short-season corn fed to broiler chicks.

The apparent ileal digestibility (AID) of amino acids (AA) in 4 pea protein isolates [PPI; experiment (Exp.) 1], 5 wheat- and corn-derived distillers grains with solubles (wcDDGS; Exp. 2), and 5 short-season corn (Exp. 3) samples for broiler chickens were determined. In addition, a reference wheat sample was included in each experiment to measure the repeatability of the ileal digestibility assay used. Birds (n = 180 for Exp. 1 and n = 216 for Exp. 2 or 3) were fed test diets from d 15 to 21 of age. Reference wheat and PPI were included in test diets at 91.7 and 25%, respectively, as the sole source of AA, whereas wcDDGS and corn were combined with wheat in test diets at 47.7% test ingredient (wcDDGS or corn) and 51% wheat as the sources of AA. Chromic oxide at 0.3% was added in all diets as the indigestible marker. Each test diet was randomly assigned to 6 cages of 6 male birds each. On d 21, birds were killed and ileal digesta were collected to determine the AID of AA. The mean AID values for indispensable AA ranged from 86.0% (Thr) to 94.7% (Arg) for PPI, 50.7% (Lys) to 79.8% (Leu) for wcDDGS, and 73.9% (Thr) to 95.3% (Arg) for corn. Overall, the CV range for AID of AA was widest for wcDDGS (8.1% for Met to 29.4% for Lys) followed by corn (3.0% for Met to 10.7% for Thr) and then PPI (2.7% for Lys to 6.1% for Thr). For wcDDGS and corn, the within-sample variation (assay condition) was more than between-sample variation (feed differences), whereas the reverse was true for PPI. No differences were detected in the AID of CP and AA for reference wheat among experiments.

Dietary guanidino acetic acid is an efficacious replacement for arginine for young chicks.

Guanidino acetic acid (GAA) is synthesized in the liver and kidney from Arg and Gly and subsequently methylated by S-adenosylmethionine to form creatine. Four bioassays were carried out to determine the capacity of GAA to serve as a dietary replacement for Arg for growing chicks. Broiler chicks were fed Arg-deficient dextrose-casein (0.88% Arg) or corn-corn coproduct-soybean meal (1.0% Arg) basal diets during 9-d battery feeding trials involving 5 pens of 4 chicks per treatment. The dextrose-casein diet was shown to be markedly deficient in Arg as both weight gain and G:F increased (P < 0.01) due to addition of Arg, GAA, or creatine. The optimal level of added GAA was 0.12% of the diet, but this level of GAA or 1.0% creatine-H(2)O did not improve growth performance when added to an Arg-adequate diet. A second assay confirmed this level of optimal Arg in a 2 × 2 factorial arrangement of l-Arg and GAA supplementation. Using a practical-type diet based on corn, corn gluten meal, distillers dried grains with solubles, and soybean meal, similar improvements (P < 0.05) in G:F resulted from addition of 0.25% Arg, 0.12% GAA, or 0.15% creatine·H(2)O. These results demonstrate that 0.12% supplemental GAA, like creatine, produces consistent growth responses in young chicks fed Arg-deficient diets. To provide further evidence of the capacity for GAA to serve as a dietary Arg replacement, the dextrose-casein diet was supplemented with 7 graded doses of Arg in the absence or presence of 0.12% GAA (14 total diets). Quadratic (P < 0.01) responses in weight gain and G:F responses to supplemental Arg were observed. Similar supplemental Arg requirements were estimated in the absence and presence of 0.12% GAA, but GAA elicited a greater improvement (P < 0.05) in G:F when added to Arg-deficient, compared with Arg-adequate, diets. Collectively, these data indicate that GAA can be used as an efficacious replacement for dietary Arg for young chicks.

Evaluation of corn distillers dried grains with solubles as an alternative ingredient for broilers.

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 fed ≥8% DDGS showed increased BW gain compared with those fed the control diet during the 0- to 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.

Standardized ileal amino acid digestibility in dry-extruded expelled soybean meal, extruded canola seed-pea, feather meal, and poultry by-product meal for broiler chickens.

Ileal digestibility of amino acids (AA) in dry-extruded expelled soybean meal (DESBM), co-extruded canola seed-pea blend (ECSP, 50:50 wt/wt basis), poultry by-product meal (PBPM), and feather meal (FM) were determined in broiler chicks. For each ingredient, 5 samples each collected on different occasions were evaluated. Birds (n = 180 for each sample) were fed a commercial starter diet from d 1 to 15 of age followed by the test diets from d 15 to 21. Dry-extruded expelled soybean meal, ECSP, PBPM, and FM were included in the test diets at 95.3, 95.3, 38.4, and 28.4%, respectively, as the sole source of AA and balanced for minerals and vitamins. Chromic oxide (0.3%) was included in all diets as a digestibility marker. Each diet (5 per ingredient) was randomly assigned to 6 replicate cages, each with 6 birds. On d 21, birds were killed to collect ileal digesta for determining the apparent ileal AA digestibility on cage basis. The standardized ileal digestibility (SID) values were calculated using ileal endogenous AA losses previously determined in our laboratory. The apparent ileal digestibility of AA ranged from 78 to 91%, 68 to 83%, 51 to 81%, and 39 to 74% for DESBM, ECSP, PBPM, and FM, respectively. The respective ranges for SID values were 83 to 96%, 72 to 85%, 58 to 86%, and 42 to 78%. Among the indispensable AA, the lowest SID was observed for Thr in all test ingredients, whereas the highest SID was observed for Phe except in ECSP in which Arg had the highest SID. The SID of Lys (CV) were 91% (2.8%), 79% (2.0%), 78% (7.4%), and 60% (10%) for DESBM, ECSP, PBPM, and FM, respectively, whereas the SID of TSAA (CV) were 88% (4.5%), 77% (2.4%), 74% (9.0%), and 55% (18%), respectively. These SID AA data will help nutritionists to formulate broiler diets that more closely match the birds' requirements and minimize nutrient excess.

Effect of incremental levels of L-lysine and determination of the limiting amino acids in low crude protein corn-soybean meal diets for broilers.

Research was conducted to determine the level of l-Lys that can be included in corn-soybean meal (C-SBM) diets for broilers before an amino acid (AA) beyond Met, Lys, Thr, or Gly becoming limiting and to determine the order of limiting AA in low CP C-SBM diets. All experiments were conducted with Ross 708 broilers (0 to 18 d of age) in brooder batteries. Treatments contained 7 or 8 replicates with 6 birds per replicate. In all experiments, a control C-SBM diet containing no l-Lys.HCl and a similar diet [positive control (PC) + Gly] with supplemental Gly to provide 2.32% total dietary Gly + Ser were fed. All diets were formulated to contain 1.26% total Lys. All diets with added l-Lys.HCl contained supplemental Gly to provide 2.32% total dietary Gly + Ser. In experiment 1, l-Lys.HCl was added to the diets at 0.02% increments from 0.15 to 0.27%. Compared with the PC + Gly diet, there were no negative effects (P > 0.10) of supplemental Lys on ADG, ADFI, or G:F. In experiment 2, l-Lys.HCl was added to the diets at 0.05% increments from 0.25 to 0.60%. Compared with the PC + Gly diet, ADG and G:F were decreased (P < 0.03) in broilers fed diets containing greater than 0.30% l-Lys.HCl but not (P > 0.10) in the 0.25% l-Lys.HCl diet. In experiment 3, l-Lys.HCl was added to the diets at 0.05% increments from 0.20 to 0.30%. Daily gain was decreased (P < 0.03) in broilers fed 0.30% l-Lys.HCl but not in those fed 0.20 or 0.25% l-Lys.HCl. In experiment 4, the order of limiting AA was determined in a C-SBM diet containing 0.45% L-Lys.HCl. In addition to the PC and PC + Gly diets, diets consisted of a negative control (NC) diet with 0.45% l-Lys.HCl, NC + 0.247% Ile, NC + 0.484% l-Arg.HCl, NC + 0.249% Val, and all possible 2- and l-way combinations of all 3 AA. Compared with the NC diet, addition of Arg and the combination of Arg and the other AA increased ADG and ADFI, indicating that Arg was the limiting AA in this diet. Experiment 5 was conducted in an identical manner to experiment 4 except the diets with the added AA contained the same ratio of corn to soybean meal that is present in a diet with 0.25% l-Lys.HCl. The results of experiment 5 suggest that Arg and Val are equaling limiting in a diet with 0.25% l-Lys.HCl. In summary, 0.25% l-Lys.HCl can be added to C-SBM diets supplemented with Met, Thr, and Gly with no negative effects on growth performance, and Arg and Val are equaling limiting (after Met, Thr, Lys, and Gly) in diets containing 0.25% l-Lys.HCl.

Amino acid composition of fetus, placenta, and uterus in gilts throughout gestation.

An accurate understanding of the AA composition of the products of conception is needed to accurately model dietary AA needs of pregnant swine. To determine AA composition in fetal pigs, the placenta, and the uterus at various stages of gestation, samples from a total of 65 gilts slaughtered at assigned days of gestation (d 43, 58, 73, 91, 101, and 108) were used. The AA concentrations (g/kg each wet tissue) in the fetus, placenta, or uterus increased as gestation progressed, with major increases occurring from d 73 to 108 of gestation ( < 0.05). For fetus, AA content on a DM basis (%) and AA contribution to total fetal AA (g/100 g total AA of fetal tissue) generally decreased as gestation progressed ( < 0.05) except for Arg and Ala, which increased from d 73 of gestation, and for Gly and Pro, which increased progressively ( < 0.05) from d 43. Placental AA content on a DM basis increased up to d 91 or 101 of gestation ( < 0.05) and then slightly decreased on d 108 of gestation except for His, Cys, and Met + Cys. Amino acid contribution to total placental AA decreased for all AA as gestation progressed ( < 0.05), except for Arg, Ala, Gly, and Pro, which increased from d 58 of gestation. Essential AA content in the uterus on a DM basis had no major changes during gestation, whereas nonessential AA content decreased ( < 0.05) as gestation progressed, except for Asp. For AA contribution to total uterine AA, some essential AA (Ile, Leu, Lys, Met, Trp, and Val; < 0.06) and Asp ( < 0.01) contributions increased with increasing gestational ages, whereas Arg ( = 0.08), Cys, Gly, and Pro ( < 0.05) contributions decreased as gestation progressed. Differences in AA contribution to total AA within each tissue varied among the fetus, placenta, and uterus by type of AA. These results demonstrate that AA compositions of fetal pigs, placenta, and uterus are changed differentially as gestation progresses; in particular, Arg, Ala, Gly, and Pro compositions in fetus and placenta increased progressively. These compositional data for each reproductive tissue and fetus will help to model AA requirements in gestation.

Effects of reducing dietary crude protein levels and replacement with crystalline amino acids on growth performance, carcass composition, and fresh pork quality of finishing pigs fed ractopamine hydrochloride.

Progeny of GPK-35 females mated to PIC 380 boars were blocked by initial BW, and within the 9 blocks, pens of pigs (3 gilts and 3 barrows/pen) were randomly assigned to dietary treatments where CP of finisher-I, -II, and -III diets was 1) 16.04, 14.55, and 16.23%, respectively (Ctrl); 2) 14.76, 13.48, and 15.27%, respectively (ILE); 3) 14.26, 12.78, and 14.28%, respectively (VAL); or 4) 12.65, 12.38, and 13.32%, respectively (NoSBM). All finisher-III diets included 10 mg/kg of ractopamine hydrochloride (RAC) and a Lys:ME ratio of 2.79 g/Mcal. At slaughter, HCW and Fat-O-Meat'er data were recorded before carcasses were subjected to a rapid chilling process. A subsample of whole hams (2/pen) and whole loins (2/pen) were transported under refrigeration to the University of Arkansas. Hams were dissected with a knife into lean, fat, and bone, and 2.5-cm-thick chops from the semimembranosus (SM) and the LM were used to measure fresh pork quality characteristics. Both ADG and G:F decreased (linear, = 0.05) as CP decreased in finisher-I diets, whereas ADFI was reduced (linear, = 0.01) in response to decreasing CP in finisher-II diets. When RAC was included in the finisher-III diets, ADFI and BW decreased (linear, ≤ 0.03) with decreasing CP, and pigs fed the ILE diet had greater (cubic, < 0.01) G:F than pigs fed the Ctrl and VAL diets. Across the entire finishing period, ADG and ADFI decreased (linear, = 0.01) in response to reductions in dietary CP. Conversely, reducing CP in finisher diets did not ( ≥ 0.13) affect carcass yield, fat depth, LM depth, or calculated fat-free lean yield, and dietary CP content did not ( ≥ 0.09) alter the lean, fat, or bone composition of fresh hams. Moreover, there was no effect of dietary CP on the visual and instrumental color or firmness of the LM ( ≥ 0.06) or SM ( ≥ 0.12). However, there were linear increases in LM marbling scores ( = 0.02) and intramuscular fat content ( = 0.03) as CP was reduced in the finisher diets. Although reducing dietary CP decreased overall ADG and ADFI by approximately 6.1 and 4.9%, respectively, carcass composition was not impacted by dietary CP level. More importantly, reducing dietary CP, although meeting the standard ileal digestible requirements for Lys, Thr, Trp, Met, Ile, and Val with crystalline AA, did not impact pork color or water-holding capacity and actually increased the intramuscular fat content of the LM.

Antibiotic inclusion in the diet did not alter the standardized ileal digestible tryptophan to lysine ratio for growing pigs.

Two 21-d experiments were conducted to determine the optimum standardized ileal digestible (SID) Trp:Lys ratio for growing pigs; 1 experiment fed diets supplemented with or without an antibiotic. The primary response variables in both experiments were ADG, ADFI, G:F, and plasma urea N (PUN) concentrations with the optimum SID Trp:Lys ratio detected using broken-line analysis. Experiment 1 evaluated the optimum SID Trp:Lys ratio in growing pigs fed diets supplemented with an antibiotic. This experiment used 120 crossbred pigs that were blocked by sex and initial BW (24.13 ± 2.72 kg) and allotted to 6 SID Trp:Lys ratios in 4 replicates. Dietary treatments were formulated by the addition of crystalline Trp to create 6 SID Trp:Lys ratios (13.08%, 14.06%, 15.04%, 17.00%, 18.95%, and 20.91%) with a constant SID Lys level of 0.655%. As SID Trp:Lys ratios increased, ADG, ADFI, and G:F increased, and PUN concentrations decreased linearly ( < 0.05) and quadratically ( < 0.05). Linear broken-line analysis yielded optimum SID Trp:Lys ratios of 17.93% ( < 0.001) and 16.17% ( = 0.009) for ADG and PUN, respectively, resulting in a mean optimum SID Trp:Lys ratio of 17.05%. Experiment 2 evaluated the optimum SID Trp:Lys ratio in growing pigs fed diets supplemented with or without an antibiotic. It used a total of 324 crossbred pigs (initial BW: 30.81 ± 3.56 kg) that were allotted to 6 SID Trp:Lys ratios in 6 replicates. Dietary treatments were formulated by the addition of crystalline Trp to create 6 SID Trp:Lys ratios (12.52%, 14.86%, 17.20%, 19.54%, 21.88%, and 24.22%) with a constant SID Lys level of 0.67%. As SID Trp:Lys ratios increased, ADG, ADFI, and G:F increased, and PUN concentrations decreased linearly ( < 0.001) and quadratically ( < 0.001) regardless of antibiotic inclusion. There were no differences by the antibiotic treatment in ADG, ADFI, G:F, or PUN concentrations ( > 0.49) and no interactions between antibiotics and Trp:Lys ratios ( > 0.29). When the data for all pigs were pooled for the various Trp:Lys ratios, the optimum SID Trp:Lys ratios for ADG and PUN based on linear broken-line analysis were 14.58% ( < 0.001) and 14.54% ( < 0.001), respectively, resulting in an optimum SID Trp:Lys ratio of 14.56% as the mean of the determined optima for ADG and PUN responses. These results demonstrate that the optimum SID Trp:Lys ratio for 30- to 50-kg growing pigs is not impacted by the dietary inclusion of an antibiotic as long as the diets are formulated on an SID AA basis.

Comparison of inorganic and organic selenium sources for broilers.

An experiment was conducted to compare the effects of organic and inorganic sources of Se on growth performance, carcass traits, breast and plasma Se concentrations, and plasma glutathione peroxidase (pGPX3) activity in broilers. Broiler chicks were sexed on d 0 and within sex, randomly allotted to dietary treatment. Average initial and final BW of the broilers were 47 and 2,684 g, and the experiment lasted 49 d. A 3-phase feeding program similar to industry recommendations was used, and the basal diets for each phase were corn-soybean meal based. For each growth phase, the basal diet was supplemented with 0 (control) or 0.30 ppm Se from sodium selenite (SS) or Se-enriched yeast (SY). Each treatment was replicated 7 times (4 pens of males and 3 pens of females) with 50 male or 55 female broilers per replicate. Daily gain, feed intake, gain:feed, eviscerated and chill weights, carcass yield, breast weight, and moisture loss from the breast were not affected (P > 0.05) by Se supplementation. Dietary supplementation with SY increased (P < 0.05) muscle and plasma Se concentrations compared with broilers fed the control diet or the diet with SS. Plasma GPX3 activity was not affected (P > 0.05) by Se source or concentration. The results from this experiment indicate that organic Se increases tissue Se concentration, but it does not affect growth performance, carcass traits, or pGPX3 activity compared with inorganic Se.

Changes in glutathione peroxidase and tissue selenium concentrations of broilers after consuming a diet adequate in selenium.

Three experiments (EXP) were conducted with commercial broilers to develop a low-Se diet for comparing plasma glutathione peroxidase (pGPX3) concentrations and then to compare pGPX3 and plasma and tissue Se concentrations in broilers fed this low-Se diet after being supplemented with sodium selenite (SS) or Se-enriched yeast (SY). With the exception of Se, all diets were nutritionally adequate. The EXP lasted from 0 to 20 or 22 d posthatching, and treatments were replicated with 6 to 8 pens of 6 to 15 chicks per pen. The results of EXP 1 and 2 indicated that a cornstarch-dextrose diet containing 10% torula yeast and 31% soybean meal (SBM) resulted in similar gain as a corn-SBM (C-SBM) diet, but the cornstarch-dextrose-torula yeast-SBM diet with no added Se reduced pGPX3 activity 6-fold. In EXP 3, the treatments were a C-SBM diet with 0 or 0.30 ppm added Se from SS or SY. These diets were fed from 0 to 10 d posthatching. Beginning on d 10, all broilers were fed the cornstarch-dextrose-torula yeast-SBM, low-Se diet. On d 10, 13, 16, 19, and 22, three broilers per replicate were randomly selected for plasma and tissue collection. Treatment differences were significant at P < 0.05. Daily gain, daily feed intake, and gain:feed were not affected by diet during the 0-to-10-d or 0-to-22-d periods. Plasma GPX3 activity and plasma, liver, and breast Se concentrations were greater in broilers previously fed the diets with added Se, regardless of source, than in those fed the C-SBM diet, except for liver Se concentration on d 19 of broilers previously fed the SS diet. The pGPX3 concentrations were not different in broilers previously fed either Se diet on d 10 and 13 but were greater in broilers previously fed the SY diet on d 16, 19, and 22. Plasma Se concentrations were not different in broilers previously fed diets with SS or SY on d 10 and 22 but were greater in broilers previously fed the SY diet on d 13, 16, and 19. Breast Se concentrations were greater in broilers previously fed the SY diet than in those fed the SS diet on each day. Liver Se concentrations were not different in broilers previously fed SS or SY diets on d 19 and 22 but were greater in those previously fed the SY diet on d 10, 13, and 16. These results indicated that SY supplementation in broiler diets resulted in greater tissue Se concentrations than SS and that pGPX3 and tissue Se concentrations remained greater in birds previously fed a diet with SY than in those fed SS after being fed a low-Se diet.

Effect of inorganic versus organic selenium on hen production and egg selenium concentration.

A 28-d experiment using 288 Hy-Line W-36 laying hens was conducted to compare sodium selenite (SS) with Se-enriched yeast (SY). The Se from SS or SY was supplemented into a corn-soybean meal basal diet at 0, 0.15, 0.30, 0.60, or 3.00 ppm, and the basal diet was formulated to provide 0.82% lysine and 2,950 kcal/kg of ME. Each treatment was replicated 4 times with 2 cages of 4 hens per cage in each replicate. Hen production was assessed daily, and 2 eggs per replicate were collected every 4 d for whole-egg Se analysis. Albumen quality was assessed at 2 egg storage temperatures (7.2 vs. 22.2 degrees C) with the eggs collected on d 24 and 28, respectively. The percentage of dirty and cracked eggs was greater (P < 0.04) in hens fed SY than in those fed SS. Percentage hen-day production was not affected (P > 0.05) by diet. Albumen quality of eggs stored at 22.2 degrees C was improved (P < 0.04) in eggs from hens fed SS, but there was no difference (P > 0.05) in albumen quality of eggs stored at 7.2 degrees C. Egg weight was linearly increased (P < 0.01) by SY. Whole-egg Se levels were linearly increased (P < 0.01) as dietary Se level increased for both sources of Se, but eggs from hens fed SY had higher (P < 0.01) Se concentrations than those fed SS. The results from this experiment indicate that percentage hen-day production is not affected by Se source, and that SY increases egg Se concentrations more than SS.

A comparison of two sources of phytase in liquid and dry forms in broilers.

Research with corn-soybean meal diets was conducted to compare phytase sources in commercial broilers. A Ca to nonphytate P (nPP) ratio of 2.5:1 was maintained in all diets. Experiments 1 and 2 were conducted from d 4 to 13 (experiment 1) or d 9 to 23 post-hatching (experiment 2) in batteries. The 10 treatments used in both experiment were: Diets 1 to 4 = 0.20, 0.25, 0.30, or 0.35% nPP; Diets 5 to 7 = diet 1 plus 100, 200, or 300 phytase units/kg of diet from Natuphos (NAT); and Diets 8 to 10 = diet 1 plus 100, 200, or 300 phytase units/ kg of diet from Ronozyme (RON). As nPP levels increased, daily gain (ADG), feed intake (ADFI), gain:feed, and toe and tibia ash percentage were linearly increased (P < 0.06) in experiments 1 and 2. Incremental addition of phytase, regardless of source, linearly increased (P < 0.07) ADG and ADFI in experiment 1. Broilers fed NAT had higher (P < 0.07) toe ash percentage in experiment 1 and 2, and higher (P < 0.02) ADG and ADFI in experiment 2 than those fed RON. In experiment 3, 3,360 broilers were used to test 2 dry phytase products from 0 to 41 d posthatching in a 3-phase feeding program. The treatments were: Diet 1) adequate Ca and nPP; Diet 2) nPP reduced by 0.20%; Diets 3 to 5 = diet 2 plus 300, 500, or 750 phytase units/kg of diet from NAT; and Diets 6 to 8 = Diet 2 plus 300, 500, or 750 phytase units/kg of diet from RON. Broilers fed the adequate Ca and nPP diet had improved ADG and ADFI overall, and tibia ash weight and percentage in all growth phases (P < 0.03) compared with those fed the reduced Ca and nPP diets. Overall, ADG and ADFI were linearly increased (P < 0.05) by incremental phytase addition in experiment 3. Both NAT and RON produce similar growth and bone ash traits in commercial broilers.

Intra-individual patterns of hormonal and affective adaptation to work demands: an n = 2 study of junior doctors.

This paper examines the detailed pattern of hormonal and affective response to natural variations in work demands, in relation to a taxonomy of adaptive response based on Frankenhaeuser's (1986) psychobiological analysis of coping modes and Hockey's (1993) regulatory control model. Two junior doctors were monitored every day over a 7-week period of work on a cardio-thoracic surgery ward. Measurements were made for each morning and afternoon work period of self-rated workload, effort and affective state, and the level of urinary catecholamines and cortisol. The de-trended data were analysed separately for the two individuals, using multivariate methods. Following reduction of work variables by principal components analysis, canonical correlation analyses were carried out for each individual. These revealed differences in the patterns of adaptation to two distinctive work contexts (enabling and demanding work) across the two doctors, as identified through loadings on two significant pairs of canonical variates. As expected, enabling work (high medical demands, with high personal resources) was associated with active coping in both subjects (low fatigue, high effort/adrenaline and low cortisol). However, demanding work (high general demands) was associated with marked differences between them in the pattern of loadings. One subject showed the strain pattern normally associated with effortful engagement in difficult tasks (high anxiety and fatigue, high effort/adrenaline), though without the anticipated reduction in cortisol. The response pattern of the other individual was indicative of passive coping (high anxiety and cortisol, with no effort/adrenaline component). The findings are interpreted in terms of the role of personal coping styles on the adaptive response to work demands. The use of canonical correlation methods with intra-individual data sets, although relatively unusual, appears to provide potentially valuable evidence on the nature of individual differences in the process of psychobiological response to stress underlying work-health relationships.

Heart rate as an indicator of stress in surgeons and anaesthetists.

Ambulatory monitoring of heart rate was used as one indication of psychological stress among 8 doctors involved in cardio-thoracic surgery and 8 doctors performing anaesthesia in the same operating theatre. Twenty-three days of recording were available and the heart rate traces were related to observations of activities made by the authors. Comparisons of mean heart rates are made for these and other occupations. Certain sorts of activities are shown to increase and decrease heart rate. The value of heart rate as an indicator of psychological stress in field studies is discussed.

Familial pancreatic cancer in south Louisiana.

Previous researchers have found high mortality and incidence rates for pancreatic cancer in the Acadiana region of southern Louisiana. While lifestyle practices such as pork and alcohol consumption and a familial trend have been linked to pancreatic cancer, cigarette smoking is the only established risk factor for pancreatic cancer. Therefore, a retrospective, descriptive study was conducted to explore lifestyle risk factors and the familial trend in pancreatic cancer. The Familial Pancreatic Cancer Questionnaire (FPCQ) was used to collect data on demographics, tobacco and alcohol use, dietary history, and medical history. A surrogate respondent (family member) for 31 pancreatic cancer subjects completed the FPCQ. Race and gender specific incidence rates (IR) for pancreatic cancer in Acadiana were calculated. Results showed that mean IRs for pancreatic cancer for Caucasian and African-American males and females were higher than national SEER rates. Pancreatic cancer and lung cancer were the most frequently reported cancers among subjects' first degree relatives. The majority (65%) of the subjects smoked. A positive family history for pancreatic cancer was found in this study with five (16%) of the pancreatic cancer subjects having one or more first degree relatives with pancreatic cancer. This percent is twice that found by previous researchers.

Effects of dietary soy isoflavones on growth, carcass traits, and meat quality in growing-finishing pigs.

Two experiments were conducted to determine the effect of soy isoflavones on growth, meat quality, and carcass traits of growing-finishing pigs. In Exp. 1, 36 barrows (initial and final BW, 26 and 113 kg, respectively) were used and each treatment was replicated four times with three pigs each. The dietary treatments were 1) corn-soybean meal (C-SBM), 2) corn-soy protein concentrate (low isoflavones, C-SPC), or 3) C-SPC + isoflavones (isoflavone levels equal to those in C-SBM). Daily gain and ADFI were increased (P < 0.10) in pigs fed the C-SPC relative to pigs fed the C-SPC + isoflavone diet in the late finishing period; otherwise, growth performance was not affected (P > 0.10) by diet. Longissimus muscle area, 10th-rib fat depth, percentage muscling (National Pork Producers Council), 24-h pH and temperature, color, firmness-wetness, marbling, drip loss, and CIE L*, a*, and b* color values were not affected (P > 0.10) by diet. Dressing percentage, carcass length, weight and percentage of fat-free lean in ham and carcass, lean gain per day, lean:fat, and ham weight were increased (P < 0.10), and ham fat and percentage fat in ham and carcass were decreased (P < 0.10) in pigs fed the C-SPC + isoflavone diet compared with pigs fed the C-SPC diet. Pigs fed the C-SPC + isoflavone diet had similar (P > 0.10) carcass traits as pigs fed the C-SBM diet, except carcass length, percentage ham lean and thaw loss were greater (P < 0.10), and total ham fat was less (P < 0.10) in pigs fed the C-SPC + isoflavone diet. In Exp. 2, 60 gilts (initial and final BW, 31 and 116 kg, respectively) were used, and each treatment was replicated five times with four pigs per replicate. The treatments were 1) C-SBM, 2) C-SBM + isoflavone levels two times those in C-SBM, and 3) C-SBM + isoflavone levels five times those in C-SBM. Daily feed intake was linearly decreased (P < 0.10) in the growing phase and increased (P < 0.10) in the late finishing phases as isoflavone levels increased; otherwise, growth performance was not affected (P > 0.10) by diet. Diet did not affect (P > 0.10) carcass traits; however, CIE a* and b* color scores and drip loss were decreased (P < 0.06) as isoflavone levels increased. Soy isoflavones decreased fat and increased lean in barrows when fed within the dietary concentrations found in typical C-SBM diets but not when fed to gilts at concentrations above those present in C-SBM diets.

Effects of a novel carbohydrate and protein source on sow performance during lactation.

Ninety-one primiparous and multiparous sows and their pigs were used to evaluate the effects of a novel carbohydrate- and protein-based feed ingredient (Nutri-Pal, NP) on sow and litter performance during lactation. Nutri-Pal is a feed supplement for sows that consists of a blend of milk chocolate, brewer's yeast, whey products, and glucooligosaccharides. The dietary treatments consisted of a corn-soybean meal control and a corn-soybean meal plus 5% NP fed from d 110 of gestation to weaning. The diets were formulated to be equal in total Lys and ME. Sows were allotted to treatment based on parity, body weight, and the date of d 110 of gestation. There were 46 and 45 sows per treatment over four farrowing groups. Litters were standardized to 10 pigs and weighed within 1 d of farrowing, and all sows weaned at least 8 pigs at an average age of 21 d. Sows were weighed on d 110 of gestation, d 1 postfarrowing, and at weaning. Sows were fed three times daily during lactation. Sows were checked twice daily after weaning for signs of estrus. The weaning weight of sows fed NP was increased (P < 0.10) compared with those fed the control diet. Sows fed the control diet tended (P = 0.11) to lose more weight per day from d 110 of gestation to weaning than the sows fed NP. Otherwise, sow response variables (sow weight on d 110 of gestation and d 1 postfarrowing, d 110 of gestation to d 1 postfarrowing and lactation weight change per day, d 110 of gestation to d 1 postfarrowing, lactation, and total feed intake, days to estrus, pigs born alive or dead, and litter and average pig birth weight) were not affected (P > 0.10) by diet. There were no effects (P > 0.10) of diet on litter performance response variables (pigs weaned, litter and average pig weaning weight and gain, and survival percent). The NP feed ingredient had minor effects on sow productivity, but it did not affect litter productivity indices.

Effect of chromium propionate on growth, carcass traits, pork quality, and plasma metabolites in growing-finishing pigs.

Two experiments were conducted to determine the effects of dietary Cr, as Cr propionate, on growth, carcass traits, pork quality, and plasma metabolites in growing-finishing swine. Ninety-six crossbred gilts (Exp. 1; initial and final BW of 28 [SEM = 0.41] and 109 [SEM = 2.11] kg) or 144 PIC Cambrough 22 barrows (Exp. 2; initial and final BW of 26 [SEM = 0.39] and 111 [SEM = 2.52] kg) were allotted to six or four dietary treatments, respectively, with six replications and four (Exp. 1) or six (Exp. 2) pigs in each replicate pen blocked by weight in randomized complete block designs. The six dietary treatments for Exp. 1 were 1) corn-soybean meal (C-SBM), 2) C-SBM + 50 ppb Cr, 3) C-SBM + 100 ppb Cr, 4) C-SBM + 200 ppb Cr, 5) C-SBM low NE diet, and 6) C-SBM low NE diet + 200 ppb Cr. The four dietary treatments for Exp. 2 were C-SBM with 0, 100, 200, or 300 ppb Cr. Growth, carcass traits, and plasma metabolite (collected on d 29 and at each phase change) data were taken at the end of both experiments and pork quality data were taken at the end of Exp. 1. There was no effect (P > 0.10) on overall growth performance when pigs were fed graded levels of Cr (Exp. 1 and 2) or Cr in the positive control or low NE diets (Exp. 1). Longissimus muscle area, ham weight, ham fat-free lean, and total carcass lean were increased in pigs fed 200 ppb in the positive control diets but decreased in pigs fed 200 ppb Cr in the low NE diets (Cr x NE, P < 0.08). There was no effect of Cr concentration (P > 0.10) on carcass traits in Exp. 2. In Exp. 1, cook loss of a fresh or a frozen chop was decreased (P < 0.10) by 200 ppb Cr. In Exp. 1, NEFA concentration was decreased (P < 0.05) in pigs fed Cr in the positive control or low NE diets during the early-finishing period. In Exp. 2, the addition of Cr decreased NEFA (quadratic, P < 0.09) and plasma urea N (linear, P < 0.02) concentrations and tended to increase total cholesterol and high density lipoproteins (quadratic, P < 0.09). In these experiments, Cr propionate had no effect on overall growth performance, variable effects on carcass traits and plasma metabolites, and some positive effects on pork quality, especially water holding capacity of a fresh or frozen chop.