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In experiment 1 (one cycle), hens were fed diets containing 0.10, 0.115, 0.125, 0.135, 0.15, or 0.45% available P (AP) from 40 to 56 wk of age, with the last diet being a positive control. Egg production, egg mass, and BW were reduced (P < 0.05) by all lower AP levels except 0.15% AP when compared with the 0.45% AP treatment. In the second experiment (two cycles with a molt), hens were initially fed diets containing 0.10, 0.12, 0.14, 0.16, 0.18, 0.20, or 0.45% AP from 21 to 63 wk of age. Diets containing 0.10, 0.12, and 0.14% AP were terminated at 35, 39, and 50 wk, respectively, due to low egg production and increased mortality. Hens fed 0.16% AP also had significantly lower production performance than hens fed 0.45% AP during the first cycle. Hens on the 0.16 to 0.45% AP treatments were induced molted at 64 wk of age by 10 d of feed removal. The hens were then returned to the same AP layer diet they had been fed from 21 to 63 wk. For the 68 to 108 wk postmolt second-cycle period, hens fed the 0.16 to 0.20% AP diets (166 to 209 mg/d) had significantly lower egg production, egg mass, and feed efficiency than hens fed 0.45% AP. The results of our study indicated that first-cycle hens required approximately 0.18% AP or 198 mg AP/hen per day, and molted hens in their second cycle had a requirement that was greater than 0.20% AP or 209 mg AP/hen per day.

The objective of this study was to evaluate several nonfeed removal methods compared with feed removal for induced molting of laying hens. An experiment was conducted using 576 Dekalb White hens (69 wk of age) randomly assigned to 1 of 8 dietary treatments. Two of these treatments consisted of feed removal for 10 d followed by ad libitum access to a 16% CP, corn-soybean meal diet or a 94% corn diet for 18 d. The other 6 treatments provided ad libitum access for 28 d to diets containing 94% corn, 94% wheat middlings (WM), 71% WM: 23% corn, 47% WM: 47% corn, 95% corn gluten feed, and 94% distillers dried grains with solubles (DDGS). At 28 d, all hens were fed a laying hen diet (16% CP), and production performance was measured for 40 wk. The 2 feed removal treatments resulted in total cessation of egg production within 6 d. Egg production of hens fed the 94% WM, 71% WM: 23% corn, corn, corn gluten feed, and 47% WM: 47% corn diets all decreased to 6% or less by d 12, 16, 19, 20, and 28, respectively. Egg production of hens fed DDGS never decreased below 18%. Body weight loss ranged from 10% (DDGS) to 26% (10-d feed removal), with the other treatments being similar at 17%. No consistent differences were observed among treatments throughout the 40-wk postmolt period for egg production, egg specific gravity, egg weight, egg yield, or feed efficiency. No differences were observed among feed removal treatments versus several nonfeed removal treatments for ovary and oviduct weights and blood heterophil:lymphocyte ratios during the molt period. In addition, interactive social behaviors were not different throughout the molt period between hens fed the 94% WM and those deprived of feed for 10 d. Our results indicate feeding WM, corn, corn gluten feed, and WM:corn diets are effective nonfeed removal methods for molting laying hens.

The objective of this study was to determine whether soybeans without the Kunitz trypsin inhibitor and lectins could be fed effectively to young chicks and pigs. Specifically, we compared the growth performance of chicks and pigs fed diets containing modified soybeans: Kunitz trypsin inhibitor-free (KF), lectin-free (LF), lectin and Kunitz trypsin inhibitor-free (LFKF), conventional soybeans (CSB), and commercially obtained, dehulled, solvent-extracted soybean meal (SBM). A 7-d chick experiment was conducted to evaluate the nutritional value of CSB, KF, LF, LFKF, and SBM. The experiment was conducted as a completely randomized design, with four replicates, five treatments, and six male chicks per pen (n = 120). The five treatments consisted of 23% CP dextrose-soybean-based diets containing KF, LF, LFKF, CSB, or SBM as the source of dietary protein. A 28-d pig experiment was conducted to evaluate the nutritional value of CSB, LF, LFKF, and SBM. Pens of four pigs were assigned randomly to a control, corn-SBM, or one of six corn-soybean diets containing raw or extruded soybean varieties as a 2 x 3 factorial arrangement of treatments in a randomized complete block design with five blocks per treatment (n = 140). Chicks fed diets containing any of the raw soybean varieties gained less weight (P < 0.05) than chicks fed SBM (22.81 g/d for SBM vs. 14.17 g/d for the raw soybeans combined). Among the raw soybean treatments, there was a greater effect on growth performance (P < 0.05) by removing both lectins and Kunitz trypsin inhibitor (ADG of 16.56 g for LFKF) than by removing each antinutritional factor separately (ADG of 14.38 and 14.11 g for KF and LF, respectively). Pig growth performance was different (P < 0.001) for SBM (ADG of 409 g) and all the varieties when extruded (ADG of 450 g for CSB, 417 g for LF, and 408 g for LFKF) compared with the raw soybean treatments (ADG of 101 g for CSB, 165 g for LF, and 266 g for LFKF). Among the raw soybean treatments, growth performance improved (P = 0.003) as the antinutritional factor, lectin, was removed from the soybean and improved further (P = 0.045) when both lectins and Kunitz trypsin inhibitor were removed. The growth-inhibiting effect of feeding modified soybeans to young animals was more detrimental for pigs than for chicks in our experiments. Soybeans without the Kunitz trypsin inhibitor and lectins cannot be fed successfully to young chicks and pigs without heating.

Four experiments were conducted to evaluate the effects of phosphorus nutrition on laying hens exposed to heat stress (HS). Hens were fed their respective diet for at least 3 wk prior to initiation of each experiment to allow the hens fed low-P diets to become P deficient. In most experiments, hens housed in non-HS conditions were pair-fed to the HS hens to maintain equal feed intake. In experiments 1 and 2, two levels of nonphytate P (NPP; deficient at 0.10 or 0.16% vs. control at 0.45%) and two temperatures (constant thermoneutral at 21 degrees C or cyclic HS up to 35 degrees C) were evaluated. Low NPP significantly reduced feed intake and hen-day egg production, but the cyclic heat treatment had no effect on hen performance. Experiment 3 was similar to experiments 1 and 2 except that constant HS was implemented. Both constant HS and low dietary NPP reduced feed intake and egg production, and there was no significant interaction between HS and dietary NPP level. In experiment 4, hens were fed 0.10 or 0.45% NPP diets and exposed to a more severe HS (38 degrees C) for 8 h. Hens fed the deficient NPP level showed a 16% incidence of severe heat distress (unable to stand, unresponsive). Our results generally indicated that there was no interaction between dietary NPP level and HS in laying hens. However, subjecting hens that had been fed a P-deficient diet to an acute HS of 38 degrees C did increase the incidence of severe heat distress.

Three chick assays were conducted to determine the effect of increasing dietary galactose (GAL), lactose (LAC), and Grobiotic-B70, a LAC fermentation product, on growth performance, toxicity, and energy utilization when fed to commercial broiler chicks. One-day-old male commercial broiler chicks were randomly assigned to treatments in each assay. In all assays, a 22% CP corn-soybean meal-dextrose basal diet containing a growth-promoting antibiotic (Bacitracin methylene disalicylate) was fed. In assay 1, GAL was added at 2, 4, 6, 10, or 15%. In assay 2, Grobiotic-B70 was added at 5%. In assay 3, GAL, LAC, and Grobiotic-B70 were each added at 2, 4, and 6%. All additions were made in place of dextrose, and diets were fed from 0 to 20 or 21 d of age. In assay 1, the 15% GAL treatment resulted in high mortality (27%) by d 3 and was terminated. The 10% GAL treatment also resulted in increased mortality, most of which occurred during the 7-to-14-d period. Inclusion of 2 and 4% GAL resulted in an improvement (P < 0.05) in growth compared to the basal diet. Inclusion of 2, 4, 6, and 10% GAL resulted in a significant linear decrease in ME n (r 2 = 0.85). In chick assay 2, 5% Grobiotic-B70 increased growth during the first 2 wk. In chick assay 3, 6% Grobiotic increased weight gain (P < 0.05) from 0 to 14 d, and addition of 2 or 4% GAL, 2 or 4% LAC, and 4 or 6% Grobiotic-B70 increased weight gain (P < 0.08) from 0 to 21 d. Our results indicate that levels of 10 to 15% GAL are toxic. In contrast, low levels of GAL and Grobiotic-B70, and possibly LAC, may increase growth of commercial broiler chicks.

In the poultry industry, several alternative methods for disposal of dead birds have been developed. This study evaluated the efficacy of a dehydrated poultry mortality-soybean meal (DPSM) product, made from 60% on-farm whole dead birds, 40% soybean oil meal, and a preservative amendment, for inclusion in broiler diets. Composite samples of the DPSM product were obtained for nutritional and microbiological analysis. A subsequent 42-d broiler growout experiment was conducted using DPSM incrementally (0 to 100%) substituted for the protein source component (i.e., soybean oil meal) in starter and grower diets. Nutritionally, the DPSM product was similar to soybean oil meal (SBOM), with approximately 51.5% CP, 2.81% Lys, 0.72% Met, 1.85% Thr, 3.14% Arg, and 1.36% TSAA. True amino acid digestibilities of DPSM, however, were higher than soybean oil meal. Likewise, crude fat (18.03%) and ash (8.00%) concentrations of DPSM were higher than those typically observed for SBOM. Although at low levels, 13 genera of bacteria (including some pathogenic organisms) were isolated from the DPSM product. When replacing SBOM in broiler starter and grower diets, DPSM, at lower, more practical replacement rates, did not significantly influence body weight, feed consumption, or feed conversion. According to the results of this study, using DPSM in partial substitution for SBOM in broiler diets was a safe, efficient, and economically feasible alternative for dead bird disposal.

An experiment was conducted using 336 White Leghorn hens (60 wk of age) randomly assigned to one of four treatments that consisted of feed removal for 4 or 10 d or no feed removal with ad libitum access to 95% corn or 95% wheat middlings molt diets that contained supplemental minerals and vitamins. At the end of the 4- or 10-d feed removal period, hens on these treatments were provided with the corn molt diet for 24 or 18 d, respectively. Hens on the corn or wheat middlings treatments were fed the diets for 28 d. At d 28, hens on all treatments were fed a corn-soybean meal (16% CP) layer diet for 40 wk (64 to 104 wk of age). Both feed removal and the wheat middlings treatments resulted in total cessation of egg production within 8 d. Egg production of hens fed the corn molt diet had decreased to 3% by d 28. Body weight loss for hens fed the corn or wheat middlings diet was approximately 15 and 8% at d 28, respectively. Hens fed the wheat middlings diet returned to production slightly faster than hens on the other treatments. Postmolt egg production and egg mass (wk 5 to 44) were generally higher for the wheat middlings and 10-d feed removal treatments than for the corn or 4-d feed removal treatments. There were no consistent differences in mortality, egg weight, egg specific gravity, feed efficiency, and layer feed consumption among treatments. This research indicates that diets with high corn or wheat middlings, particularly wheat middlings, are effective nonfeed removal methods for molting hens.

Two experiments were conducted to evaluate the utilization of several different soy products at different ages in New Hampshire x Columbian male chicks. Six pens of eight chicks were fed dextrose-protein source diets (23% CP) containing 1 of 10 different protein sources from 0 to 21 d of age. Excreta were collected at 0 to 2, 3 to 4, 7, 14, and 21 d of age, and AMEn and amino acid (AA) digestibility were determined using acid-insoluble ash as a marker. Protein sources evaluated were as follows: Experiment 1--casein, soybean meal (SBM), soy protein concentrate (SPC), and soy protein isolate (SPI); Experiment 2-raw soyflakes, SBM, Williams 82 soybeans, heated Williams 82 soybeans, Kunitz-free soybeans (reduced trypsin inhibitor), lectin-free soybeans, and Kunitz/lectin-free soybeans. In Experiment 1, when comparing the MEn and AA digestibility values among diets at the same age, the ranking (from highest to lowest) for the four diets was casein, SPI, SPC, SBM. The MEn values increased (P < 0.05) with age for all four diets, with the increase being much smaller for the casein diet (3%) than the soy diets (mean increase of 13%). In Experiment 2, the SBM diet yielded the highest (P < 0.05) growth performance, MEn and AA digestibility values. The MEn and AA digestibility values of the Williams 82 soybeans, Kunitz-free soybeans, and lectin-free soybeans diets were much lower than those for the SBM diet. In general, the Kunitz/lectin-free soybeans yielded higher growth performance and MEn values than the Williams 82 soybeans, Kunitz-free soybeans, and lectin-free soybeans. The MEn values increased with age for most diets, and AA digestibility increased with age for the soyflake and Kunitz/ lectin-free soybean diets. Our results suggest there may be some potential benefits of feeding SPC or SPI during the first 1 to 3 wk posthatching and that underprocessed (under heated) soybeans should not be included in the diets of very young chicks.

Two experiments were conducted to determine the effects of fasting, feeding Oasis, or feeding a corn-soybean meal (SBM) or dextrose-casein diet immediately after hatching on growth performance, MEn and apparent amino acid (AA) digestibility. In each experiment, five or six pens of eight chicks were assigned to one of five treatments: feeding a corn-SBM or dextrose-casein diet immediately after hatching, fasting for 48 h (no feed or water) after hatching, or feeding Oasis for 24 or 48 h (no water) after hatching. The fasting and feeding Oasis treatments were followed by feeding the corn-SBM diet for 21 d. Excreta were collected at 0 to 2, 3 to 4, 7, 14, and 21 d on feed for determination of MEn and AA digestibility. Fasting chicks for 48 h posthatching significantly depressed weight gains compared to all other treatments at 21 d of age. Although weight losses were not significantly different at 48 h posthatching, chicks fed Oasis for 48 h had significantly (P < 0. 05) higher weight gains at 1 and 3 wk of age than did chicks fasted for 48 h. Chicks fed the dextrose-casein diet had significantly (P < 0.05) higher weight gains at 48 h and 7 d posthatching than chicks fed the corn-SBM diet immediately after hatch in Experiment 2. As time on feed increased from 3 to 21 d, MEn increased substantially (25%) for all the treatments in which chicks were fed the corn-SBM diet. In addition, the MEn of the corn-SBM diet for chicks fed Oasis was significantly (P < 0.05) higher for than chicks fasted for 48 h. The MEn of the dextrose-casein diet was high immediately after hatching and increased only slightly (2%) with increasing age. Digestibility of most AA increased with increasing age for all the corn-SBM treatments, and the digestibility values were similar among treatments. However, AA digestibility values for the dextrose-casein diet were consistently high at all ages and much higher (P < 0.05) than the other dietary treatments. Our results indicated that feeding Oasis (compared to fasting) had a beneficial effect on growth performance and subsequent energy utilization of a corn-SBM diet and that Oasis may stimulate early gut development even though very early growth (0 to 48 h) is not affected.

The nutritional value of a newly discovered sorghum mutant cultivar (P851171), with high in vitro protein digestibility, was compared to those of corn and two normal sorghums (P721N and 611Y) in two chick feeding trials. Although 8-20 day protein efficiency ratios and net protein ratios of all three sorghums were inferior to those of corn, P851171 and 611Y had markedly greater mean true amino acid digestibilities (TAAD) than either corn or P721N. In a subsequent 42-day experiment, all three sorghums supported weight gains equal to those of the corn-fed chicks. Feeding suboptimal levels of dietary protein resulted in reduced weight gains and no observed benefits of P851171 or 611Y. Furthermore, chicks fed P851171 exhibited poorer feed/gain values as compared to those fed the other cereals. It is possible that the starch content/carbohydrate profile of P851171 was inferior to that of the other sorghums, which offset its superior TAAD and resulted in poorer broiler performance.

The objectives of this study were to evaluate the effects of feeding 5 different energy and nutrient dense diets to Hy-Line W-36 hens on long-term performance and economics. A total of 480 19 wk old Hy-Line W-36 Single Comb White Leghorn hens were weighed and randomly allocated to 6 replicate groups of 16 hens each (2 adjacent cages containing 8 hens per cage, 60.9 × 58.4 cm) per dietary treatment in a randomized complete block design. The hens were fed 5 treatment diets formulated to contain 85, 90, 95, 100, and 105% of the energy and nutrient recommendations stated in the 2009 Hy-Line Variety W-36 Commercial Management Guide. Production performance was measured for 52 wk from 19 to 70 wk age. Over the course of the trial, a significant increasing linear response to increasing energy and nutrient density was seen for hen-day egg production, egg weight, egg mass, feed efficiency, energy intake, and body weight (BW). Feed intake showed no significant linear level response to increasing energy and nutrient density except during the early production cycle. No consistent responses were noted for egg quality, percent yolk, and percent egg solids throughout the study. Significant linear responses due to energy and nutrient density were seen for egg income, feed cost, and income minus feed cost. In general, as energy and nutrient density increased, egg income and feed cost per hen increased, but income minus feed cost decreased. Overall, these results indicate that feeding Hy-Line W-36 hens increasing energy and nutrient-dense diets will increase egg production, egg weight, egg mass, feed efficiency, energy intake, BW, egg income, and feed cost, but decrease egg income minus feed cost. However, these benefits do not take effect in early production and seem to be most effective in later stages of the production cycle, perhaps “priming” the birds for better egg-production persistency with age.

An experiment was conducted using 588 Hy-Line W-36 hens (68 wk of age) to evaluate if laying hens can be successfully molted by ad libitum feeding various levels of 3 sources of distillers dried grains with solubles (DDGS). Treatment 1 consisted of a 47% corn (C):47% soy hulls (SH) molt diet (C:SH) fed for 28 d (positive control). Treatments 2, 3, and 4 were molt diets containing 94% DDGS from the 3 sources fed for 28 d. Treatments 5, 6, and 7 were 32% C: 42% SH: 20% DDGS, from each of the 3 DDGS sources, also fed for 28 d. At the end of the 28-d molt period, all hens were fed a 16% CP corn-soybean meal layer diet. Body weight loss during the molt period was significantly greater (P < 0.05) for hens fed the C:SH diet (26%) than hens fed the diets containing DDGS, and the reduction in BW loss varied among DDGS sources. Feed intake was lower (P < 0.05) for the C:SH control treatment compared with most DDGS treatments. Hens fed the C:SH diet had egg production near 0% during the last 3 wk of the molt period. Hens on the other treatments did not have mean egg production below 17% during the molt period (wk 1 to 4), and the reduction in egg production varied among DDGS sources. Postmolt hen-day egg production (5-41 wk) did not significantly differ among treatments; however, egg mass and egg specific gravity were generally reduced (P < 0.05) for hens fed the 94% DDGS molt diets compared with hens fed the C:SH diet. This study showed that molt and postmolt performance responses varied among DDGS sources; however, none of the molt diets containing 20 to 94% DDGS yielded molt period reductions in BW or egg production similar to a 47% C: 47% SH diet.

Data previously reported in several studies have suggested that phytase improves amino acid digestibility in chicks. It was the objective of the current study to determine if phytase would increase the protein efficiency ratio (PER) values (g weight gain per g protein intake) for several feed ingredients fed to chicks. Six experiments were conducted and ingredients evaluated were casein, soybean meal, canola meal, cottonseed meal, peanut meal, wheat middlings, wheat bran, rice bran, defatted rice bran, meat and bone meal, and corn gluten meal. Casein was evaluated to serve as a phytate-free control ingredient. Each feedstuff was analyzed for CP and included in cornstarch:dextrose diets as the only source of protein to provide 10% dietary protein in Experiments 1 to 5 or 18% dietary protein (soybean meal) in Experiment 6. Dietary Ca and nonphytate P levels were varied among experiments and ranged from 0.95 to 1.5% Ca and 0.35 to 0.675% nonphytate P. The test ingredient diets were fed with 0 or 1,200 units of phytase/kg to New Hampshire x Columbian chicks from 8 to 17 or 20 d of age. The PER values varied greatly among ingredients, ranging from 1.4 for corn gluten meal to 4.2 for canola meal. Phytase addition had no significant effect (P > 0.10) on PER values for any of the ingredients evaluated, except for an increase for casein in one experiment. The results indicated that 1,200 U of phytase/kg did not significantly increase protein utilization of several feed ingredients as assessed by a PER chick growth assay.

We used a total of 504 commercial Single Comb White Leghorn hens (69 and 65 wk of age) in each of two experiments, and hens were induced to molt by feed withdrawal only. Feed withdrawal lasted for 12 and 11 d, and hens lost 26 and 25%, body weight in Experiments 1 and 2, respectively. All hens were then weighed, and seven replicate groups of 12 hens each were assigned to molt diet treatments. In Experiment 1, diets consisted of a corn basal diet (7.9% CP) or corn basal diet supplemented with 7.5 or 10% spent hen meal (SHM) each from two different sources. In Experiment 2, the corn basal diet or this diet supplemented with 5 or 10% SHM alone or 5% SHM plus Met, Lys, and Trp was evaluated. A molt diet of 16% CP corn-soybean meal was used as a positive control in both experiments. Molt diets were fed for 15 d in both experiments, at which time all hens were fed a 16% CP layer diet. Performance was measured for 8 wk following the beginning of feeding the layer diet. Feeding the low-protein corn molt diet supplemented with 5 to 10% SHM improved early postmolt egg production performance and body weight gain compared with hens fed the corn basal diet alone. The 7.5 and 10% SHM diets yielded early postmolt performance that was not significantly different (P > 0.05) from that of hens fed the high-protein (16% CP) diet. Supplementing the 5% SHM diet with amino acids generally did not significantly improve performance. The present study thus indicates that improved early postmolt performance may be achieved by supplementation of a low-protein corn molt diet with 5 to 10% SHM.

Microbial protein represents the majority of metabolizable protein absorbed by ruminant animals. Enhanced understanding of the AA digestibility of rumen microbes will improve estimates of metabolizable protein. The objective of this experiment was to determine the digestibility of AA in fluid- (FAB) and particle-associated bacteria (PAB) using the precision-fed cecectomized rooster bioassay. Bacteria were isolated from 4 ruminally cannulated lactating Holstein cows by differential centrifugation, including particle suspension in 0.1% Tween-80 for increased removal of PAB from ruminal digesta. Samples of FAB and PAB were fed to 9 cecectomized roosters to determine standardized digestibility of AA. Total AA digestibility was 76.8 and 75.5% for FAB and PAB, respectively, but did not differ. Differences existed in AA digestibilities within bacterial type when compared with the mean essential AA digestibility value. Compared with previous literature estimates of AA digestibility in microbes (mean = 76%; range=57–87%) and relative to National Research Council estimates of total AA from rumen bacteria (80%), the precision-fed cecectomized rooster assay is an acceptable in vivo model to determine AA digestibility of rumen bacteria.

In the future, it may become desirable or required to process meat and bone meal (MBM) under pressure to reduce human health concerns associated with bovine spongiform encephalopathy (BSE). Therefore, three experiments evaluated the effects of different processing pressures on the digestibility of amino acids (AA) in MBM when the pressure processing was done after typical rendering (Experiments 1 and 2) or during the initial rendering process of raw materials (Experiment 3). Processing pressures varied from 0 to 60 psi in experimental or commercial feather meal cookers. Increasing pressure during processing reduced MBM Cys concentrations in Experiments 1 and 2. True digestibilities of most AA were significantly decreased by increasing pressures in Experiments 1 and 2, and reductions were generally largest for Cys and Lys, particularly Cys, and increased with severity as pressure increased. For example, in Experiment 1, Cys digestibility decreased from 65 to 50 to 15%, and Lys digestibility decreased from 76 to 68 to 41% as the MBM was processed at 0, 30, and 60 psi, respectively, for 20 min. When the pressure processing occurred during the initial rendering of the MBM raw material (Experiment 3), a significant reduction in digestibility of most AA was observed only at 60 psi, and the decrease was much less than that observed in Experiments 1 and 2. Our results indicate that pressure processing of MBM decreases the digestibility of AA for poultry. Thus, pressure processing of MBM to reduce potential BSE infectivity will likely decrease the nutritional value of the MBM.

Three chick experiments and two cecectomized rooster experiments were conducted to determine P bioavailability and amino acid (AA) digestibility in two low phytate corns (LP), a high protein corn (HP), and a corn containing both low phytate and high protein content (HP/LP) compared with conventional corn (CONV). From 8 to 20 or 21 d of age, 1-wk-old New Hampshire x Columbian chicks were fed a cornstarch-dextrose-soybean meal (SBM) basal diet containing 0.10% available P or the basal diet supplemented with two concentrations of P (0.05 or 0.06% and 0.10 or 0.12%) from KH2PO4 or two concentrations of the corns (20 or 21% and 40 or 42%). Bioavailability of P based on tibia bone ash was much higher for LP than for CONV; values ranged from 21 to 40% for CONV and from 59 to 95% for LP. Digestibility of AA in cecectomized roosters indicated no significant differences (P0.05) between CONV and HP in the first rooster experiment. Digestibilities of eight AA, including lysine, methionine, and arginine, in LP and HP/LP were higher (P0.05) than those in CONV in the second rooster experiment. The results of this study indicated that the P in LP was two to three times more bioavailable than the P in CONV and that the digestibilities of AA in HP/LP were equal to or higher than those in CONV.

Although it is well accepted that soybean meal (SBM) is a high-quality feed ingredient for poultry, the digestibility of the dry matter and energy in SBM are quite low. One possible means for improving the digestibility of SBM is the use of enzymes. Twelve SBM, obtained from commercial processing plants in the U. S. and other countries, were evaluated with and without the addition of Avizyme in four 2-wk broiler chick assays. The analyzed values (%) of selected nutrients (mean and range) in the SBM were: CP, 45 (40 to 49); dry matter, 88 (87 to 89); lysine, 2.9 (2.57 to 3.27); methionine, 0.69 (0.60 to 0.75); cystine, 0.64 (0.60 to 0.76). KOH protein solubility (%) in the SBM (mean and range) was 77 (71 to 83). Growth performance and ileal digestible energy (DE) for chicks were affected by SBM source (P .10) on chick growth performance but significantly increased ileal DE (P

In the first of two experiments (20 to 70 wk of age), eight treatments consisted of corn-soybean meal diets (0.34% total P, 3.8% Ca, 17% CP, 2,758 kcal ME/kg) containing 0.10, 0.15, 0.20, 0.25, or 0.45% available P (AP), with the three lowest AP diets supplemented with 300 units of phytase/kg of diet. A second experiment evaluated the effect of feeding the 0.10% AP diet with and without phytase on performance and time required for onset of P deficiency in older hens (70 to 76 wk of age). In Experiment 1, the 0.10% AP diet with no supplemental phytase depressed performance by 28 wk of age. No other significant differences in performance were observed among treatments for the entire 20- to 70-wk period except that the 0.15% AP diet with no phytase resulted in body weights and tibia ash that were lower (P < 0.05) than those of hens fed the 0.45% AP diet during the last 30 wk. The mean daily AP intake of hens fed the 0.10% AP, 0.15% AP, 0.45% AP, or 0.10% AP + phytase diets was 94,159, 499, or 108 mg, respectively. Excreta P concentration was decreased by approximately 50% in birds consuming 0.10% AP + 300 U/kg phytase compared with those consuming 0.45% AP. In the second experiment, P deficiency signs occurred within 3 wk of consuming the unsupplemented corn-soybean meal diet (0.10% AP) compared with 8 wk in Experiment 1. The results of this study indicate that phytase improves P utilization in corn-soybean meal diets for laying hens and that a corn-soybean meal diet containing 0.15% AP (159 mg AP/d) or containing 0.10% AP + 300 units of phytase/kg (108 mg AP/d) supported optimal egg production from 20 to 70 wk of age. Additionally, results suggested that older hens may exhibit P deficiency symptoms sooner than younger hens.

The effect of drinking water source (well vs. city water) on laying hen performance was evaluated using 48 commercial layers (64 wk of age) housed in an environmentally controlled facility at a density of two birds per cage (12″ × 18″). After a 10-day adjustment period, four replicate groups (six hens each) were provided water from a commercial egg production farm (drilled well) and the other four groups were provided city water for 4 wk of egg production. The results indicated that water quality differed between the two water sources. A water analysis revealed that the farm well water had sodium and chloride concentrations of 190 and 210 ppm, respectively, compared to sodium and chloride concentrations of 29 and 80 ppm, respectively, for the city water. Average water consumption for the 4-wk experiment was significantly lower for hens consuming well water. Hen-day egg production and egg yield was also lower for hens consuming the well water. Egg weight, feed consumption, feed efficiency, egg specific gravity, and manure moisture were not affected by water source. These results indicate that the quality of drinking water may affect layer performance.

Commercial White Leghorn hens (65, 63, or 70 wk of age in Experiments 1, 2, and 3, respectively) were induced molted by feed withdrawal until approximately 28% body weight was lost. All hens were then weighed, and seven replicate groups of 12 hens each were fed molt diets. In Experiment 1, three diets consisted of a corn basal diet (7.9% CP) or this diet supplemented with corn gluten meal (CGM) and Lys or feather meal (FM), Met, and Lys. In Experiments 2 and 3, varying levels of FM and FM with Met and Lys were evaluated. A 16% CP corn-soybean meal diet was used as a positive control in all experiments. The molt diets were fed for 17, 15, and 17 d in Experiments 1, 2, and 3, respectively, and production performance was measured for 8 wk from the beginning of feeding the layer diet. In all experiments, hens fed the 16% CP corn-soybean meal molt diet returned to egg production and regained body weight at a faster rate than did hens fed any of the other diets. In Experiment 1, early egg production of hens fed the corn basal diet supplemented with CGM and Lys or supplementation with FM, Met, and Lys was greater (P < 0.05) than that of hens fed the basal diet alone. In Experiment 2, very early egg production (Week 1) and body weight gain were lower (P < 0.05) for hens fed the corn basal diet than for hens fed the basal supplemented with FM, Met, and Lys. The addition of 5.75 or 8.5% FM or 5.75% FM plus Met and Lys generally increased (P < 0.05) early egg production and postmolt body weight gain compared to the corn basal diet in Experiment 3. The present study thus indicated that improved early postmolt performance may be achieved by supplementation of a low-protein corn molt diet with various combinations of CGM, FM, Met, and Lys.

This study evaluated the nutritional value of raw lectin-free soybeans in comparison with raw Kunitz trypsin inhibitor-free soybeans, raw conventional soybeans, and commercial heat processed soybean meal (SBM). Analyzed lectin values (milligrams per kilogram) were 7.2, 7.1, and0.00015 for the Kunitz-free, conventional, and lectin-free soybeans, respectively. Three experiments were conducted using New Hampshire x Columbian male chicks fed 23% CP dextrose-soybean diets from 8 to 17 d of age. Growth performance of chicks fed lectin-free soybeans was greater (P0.05) than that of chicks fed raw conventional soybeans in all three experiments. However, performance of chicks fed lectin-free soybeans was lower than that of chicks fed Kunitz-free soybeans or SBM. The SBM yielded weight gains and feed efficiencies that were much higher than those observed from any of the raw soybeans. True amino acid digestibility and TMEn of the lectin-free and conventional soybeans were determined using the precision-fed cecectomized rooster assay. Seven roosters were crop-intubated with 30 g of soybeans and excreta were collected for 48 h. Digestibility coefficients of most amino acids for lectin-free soybeans were 5 to 8 percentage units higher than those for conventional soybeans, but the differences were not significant (P0.05). Likewise, the TMEn for lectin-free soybeans was 11% higher than that for raw conventional soybeans (3.577 vs 3.227 kcal/g DM) but the difference was not significant (P0.05). The results of this study indicate that the nutritional value of raw lectin-free soybeans is greater than raw conventional soybeans but is less than raw Kunitz-free soybeans and SBM, suggesting that trypsin inhibitor is a greater antinutritional factor than lectins.

An experiment was conducted to determine the effect of acute heat stress exposure on amino acid digestibility in laying hens. A total of 30 commercial laying hens were singly housed in an environmentally controlled facility, fed a standard laying ration, and exposed to a constant thermoneutral temperature (21 C) for 12 d. The hens were then randomly fed one of three diets (10 hens per diet) and exposed to three consecutive temperature periods (8 d each), which consisted of: 1) a constant 21 C temperature, 2) a cycling temperature of 35 C for 12 h and 29 C for 12 h, and 3) a constant 21 C temperature. The three isonitrogenous (18% CP) diets fed were: 1) a corn-soybean meal diet, 2) a corn-soybean meal diet containing 15% meat and bone meal, and 3) a corn-soybean meal diet containing 5% alfalfa meal and 20% wheat bran. Excreta were collected from all hens during the last 4 d of each temperature period and apparent amino acid digestibility was determined. There was a significant diet effect (P < 0.05) on amino acid digestibility. Digestibility of amino acids in Diet 2 (corn-soybean meal/meat and bone meal) was higher (P < 0.05) than in the other two diets. In addition, digestibility of amino acids in Diet 3 (corn-soybean meal/alfalfa meal/wheat bran) was significantly lower (P < 0.05) than in Diets 1 or 2. Heat stress generally had no significant effect on amino acid digestibility except for His and Lys digestibility. Histidine digestibility was higher during the heat stress period than during the initial and recovery thermoneutral periods, whereas Lys digestibility was higher during the heat stress period than during the initial thermoneutral period. These results indicated that acute heat stress (8 d) had no adverse effects on dietary amino acid digestibility in laying hens.

Experiments were conducted to determine whether the digestible Lys, Met, and TSAA in a high and low quality meat and bone meal (MBM) were totally bioavailable for protein synthesis in chicks. True digestibility of amino acids (AA) in the two MBM was determined by the precision-fed cecectomized rooster assay. Bioavailability of the digestible AA was then assessed in three slope-ratio chick growth assays using Lys-, Met-, or TSAA-deficient crystalline AA basal diets that were supplemented with varying levels of the test AA, high or low quality MBM, or AA mixtures simulating the mean digestible AA composition of the high and low quality MBM. Response parameters were weight gain, feed efficiency, body N gain, and body Lys gain in the Lys assay and weight gain and feed efficiency in the Met and TSAA assays. Bioavailability values for the digestible Lys, Met, and TSAA in the MBM and AA mixtures simulating MBM varied depending on response parameter, with values based on feed efficiency generally being highest. No consistent differences in bioavailability of the digestible AA were observed between the two MBM when all AA were considered; however, the bioavailability of the digestible Lys in the low quality MBM was lower than that in the high quality MBM for two of four performance criteria. When considering all response parameters and the AA mixture results, bioavailability of the digestible Lys and Met in the two MBM was generally 90% or greater, whereas bioavailability of the digestible TSAA was only 80% or less. The results of this study indicated that essentially all of the digestible Lys and Met in MBM were bioavailable for protein synthesis and metabolism but suggested that a significant amount of the TSAA, particularly Cys, was not bioavailable.

The digestibility and bioavailability of amino acids (AA) in meat and bone meals (MBM) may vary greatly due to different processing conditions. In the present study, two experiments were conducted to evaluate formulation of diets containing high or low quality MBM on a total AA basis vs a digestible or bioavailable AA basis compared to a corn-soybean meal control diet. Lysine, methionine, and cystine digestibilities (precision-fed cecectomized rooster assay) were 92, 91, and 71%, respectively, for high quality MBM and were 71, 83, and 31%, respectively, for the low quality MBM. Bioavailability values (slope-ratio chick growth assay) for TSAA in the two MBM were approximately 15 percentage units lower than the digestibility values. Male crossbred chicks were fed a 20% CP corn-SBM diet or corn-SBM diets containing 10 or 20% high or low quality MBM that were formulated to be equal in total, digestible, or bioavailable AA to the corn-SBM diet. All diets contained 3,200 kcal of TMEn/kg, 1.4% Ca, and 0.7% nonphytate P and were fed to chicks from 8 to 22 d posthatching. Growth performance of chicks fed 10 or 20% high or low quality MBM on a total AA basis was lower (P < 0.05) than that of chicks fed the corn-SBM diet. Growth of chicks fed 10% low quality MBM or 10 or 20% high quality MBM on a digestible or bioavailable basis was equivalent to that of chicks fed the corn-SBM diet; however, dietary inclusion of 20% low quality MBM depressed growth (P < 0.05) even on a digestible or bioavailable AA basis. Further supplementation of the latter diet with additional AA yielded growth that was similar to the corn-SBM control diet. The results indicated that formulation of diets containing MBM on a digestible or bioavailable AA basis is superior to formulation on a total AA basis. However, feeding high levels of a low quality MBM may require additional AA supplementation to obtain maximum chick growth.

1. Two chick assays (from 8 to 17 d posthatching) were conducted to determine the order of amino acid (AA) limitation in poultry by-product meal (PBPM) using AA deletion and addition assays. 2. In the deletion assay, the basal diet contained 155 g/kg crude protein (provided solely by PBPM) and was fortified with cystine, tryptophan, threonine, lysine, valine, isoleucine, histidine, methionine and phenylalanine to meet the Illinois ideal AA Pattern. Each AA was then deleted individually from the basal diet and its effect on growth assessed. 3. In the addition assay, various individual or combined additions of nine AAs were made to an unfortified 155 g/kg crude protein diet containing PBPM as the sole source of dietary crude protein. 4. The results from the deletion assay were in general agreement with those from the addition assay. Based on the combined results of the deletion and addition assays, the order of AA limitation in PBPM was 1) cystine, 2) tryptophan, 3) threonine and lysine, 5) valine, and 6) isoleucine and histidine with the degree of deficiency of valine, isoleucine and histidine being similar. The results also suggested that methionine may be slightly limiting in PBPM protein.

Experiments were conducted to determine the protein efficiency ratio (PER) and net protein ratio (NPR) of meat and bone meals containing 24 or 34% ash, poultry by-product meals containing 7 or 16% ash, lamb meals containing 15 or 24% ash, a lamb meal analog containing 19% ash (mixture of lamb meal and turkey meal), and two meat and bone meals processed at either a low or a high temperature. The PER values (weight gain per unit of protein intake) and NPR values (PER corrected for maintenance) were determined using a chick growth assay in which chicks were fed a N-free diet or 10% CP diets containing one of the animal meals as the only source of dietary protein for 6, 9, or 13 d. The PER of the lamb meal analog was greater (P < 0.05) than that of the other meals, and the PER values of the poultry by-product meals were generally greater than those for the lamb and meat and bone meals. The PER values for the lamb meals were higher than those for most of the meat and bone meals. The PER of the 34% ash meat and bone meal was lower (P < 0.05) than the PER of the 24% ash meat and bone meal (1.03 vs 1.63, respectively, at 9 d). Further experiments showed that the lower PER of the high ash meat and bone meal was not due to its high Ca and P content. Ash content had no significant effect on PER of the poultry by-product and lamb meals. The PER of the low-temperature meat and bone meal was higher (P < 0.05) than the PER of the high-temperature meat and bone meal. The relative differences in NPR values among the animal meals were similar to those observed for PER values. Decreasing the length of the assay from 13 to 6 d increased the PER and NPR of all meals but had little or no effect on the ranking of values among meals. The results of this study indicated that PER and NPR values of animal meals were influenced by raw material source, and that ash content and processing temperature affected the PER and NPR of meat and bone meal. The results also indicated that PER and NPR assays could be reduced to 6 d without reducing sensitivity.

To obtain information on the nutrient content and variability of spent hen meal, we examined meal produced form end-of-lay hens by three Renderers using conventional rendering procedures. Meal from three Renderers varied considerably in nutrient content. Amino acid content as percentage of sample varied among Renderers, but when expressed as percentage of protein less variability was observed, especially for amino acids of practical concern. Although amino acid digestibility varied somewhat among sources, overall agreement was good; values in the present study should provide guidelines for estimating digestible amino acid content of spent hen meals produced by conventional rendering. Mean amino acid digestibility among sources was not directly associated with digestibility in 0.2 or 0.002% pepsin. Nutrient content of samples produced by a commercial renderer over a 27-wk period appeared reasonably consistent

Broiler chicks were fed on chemically-defined crystalline amino acid diets containing graded levels of L-threonine (Thr) during the period 10–20 d post-hatching. Doses of Thr represented 5,10,15,40,55,70 and 95% of its ideal level for maximal weight gain and feed efficiency. Other amino acids were maintained at minimized excess levels that were 15% (of ideal) above the various doses of Thr. Following 10d of feeding and a 24h fast, chicks were killed for whole-body protein and amino acid analysis. Using pen accretion means, weight gain (r20·98), protein accretion (r2 0·99), and Thr accretion (r2 0·99) were linear (P0·75. Increasing doses of Thr resulted in increased (P

Two experiments were conducted from 0 to 21 d of age and evaluated diets containing combinations of fine or coarse ground corn (557 or 1,387 μm, respectively), whole sorghum, 15% corn distillers dried grains with solubles (DDGS), or a prebiotic-type product containing yeast cell wall, lactose, citric acid, and other fermentable carbohydrates. In experiment 1, feed efficiency was decreased (P0.001) after the first week of age for broilers fed diets containing whole sorghum, whereas broilers receiving diets with 15% DDGS had increased feed efficiency (P0.03) compared with those receiving no DDGS. In the second experiment, BW gain was increased (P0.03) after the first week of age for broilers fed diets containing the prebiotic and DDGS compared with their respective controls. In experiment 1, the diet containing sorghum yielded the highest AMEn value (P0.03). In experiment 2, diets containing the combination of the prebiotic + DDGS yielded higher AMEn values (P0.004) at 7 and 21 d compared with diets containing no combination. The effects of diet on amino acid digestibility were generally small and inconsistent in both experiments. In experiment 1, broilers fed the coarse corn or whole sorghum diets had increased (P0.0001) relative gizzard weights compared with broilers fed the fine corn diet. Also, diets containing DDGS yielded increased relative gizzard weights (P0.05) compared with diets containing no DDGS. In experiment 2, there was a decrease (P0.03) in cecal Escherichia coli when the combination of the coarse ground corn, prebiotic, and DDGS was fed in comparison with broilers receiving no prebiotic or DDGS. These results indicate that diets containing coarsely ground corn or whole sorghum in combination with DDGS can be fed to broilers with no long-term adverse effects on growth performance and nutrient digestibility and that these ingredients can have beneficial effects on AMEn, gizzard size, and cecal microflora in some instances.

The nutritional values of a novel reduced-oligosaccharide soybean meal (SBM-RO) and conventional SBM (SBM-CV) were evaluated and compared in 4 experiments. The first experiment was a TMEn assay with conventional roosters. The second experiment was a precision-fed cecectomized rooster assay that was conducted to determine TMEn and amino acid (AA) digestibility. The third experiment was a standardized ileal AA digestibility assay, in which broiler chicks were fed semi-purified diets containing 20% protein (from only the test ingredient) for 17 to 21 d of age and ileal digesta were collected on d 21. The fourth experiment was a growth performance trial (7 to 20 d of age) where broiler chicks were fed corn-SBM diets (adequate in all AA) containing 38.84% SBM-RO or SBM-CV. The protein content (100% DM basis) of the SBM-CV and SBM-RO was 51.9 and 54.8%, respectively. The gross energy of the 2 SBM was similar. The TMEn values in both conventional roosters and cecectomized roosters were significantly higher (P0.05) for SBM-RO than for SBM-CV (difference was approximately 200 kcal/kg of DM). Amino acid digestibility in cecectomized roosters was not different between SBM-CV and SBM-RO, with the exception of Trp, Ala, Asp, and Cys (SBM-ROSBM-CV, P0.05). No significant differences between the SBM were found for AA digestibility in the standardized ileal AA digestibility assay. In the growth performance trial (experiment 4), the corn-SBM diet containing SBM-RO yielded significantly higher feed efficiency than the diet containing SBM-CV (P0.001). The results indicated that the SBM-RO contains higher ME than the SBM-CV and that digestibility of AA in SBM-RO is similar to SBM-CV.

Four experiments were conducted to determine the digestible Thr requirement of commercial broiler chickens (Ross x Hubbard) during the period 3 to 6 and 6 to 8 wk posthatching. Threonine-deficient corn-peanut meal basal diets (3,200 MEn/kg) contained 20% CP and 0.50% Thr for 3- to 6-wk-old birds, and 18.3% CP and 0.50% Thr for 6- to 8-wk-old birds. True digestibility assessment using cecectomized roosters indicated that Thr was 81% digestible in both basal diets. Thus, both diets contained 0.40% digestible Thr. Growth rate and feed efficiency of chicks fed the corn-peanut meal basal diets supplemented with surfeit Thr was equal to that of chicks fed a 20% CP Met-fortified corn-soybean meal diet. Graded doses of Thr produced marked responses (P0.05) in weight gain and feed efficiency in birds of both age groups. Maximal feed efficiency was achieved at 0.61% digestible Thr in 3- to 6-wk-old birds and at 0.52% digestible Thr in 6- to 8-wk-old birds. Extrapolating these digestible Thr requirements to total requirements for chicks consuming corn-soybean meal diets (Thr digestibility = 87%) results in estimates of 0.70 and 0.60% for broiler chickens during the growth periods 3 to 6 and 6 to 8 wk posthatching, respectively. These estimates are lower than those of NRC (1994) but are in close agreement with those obtained from ideal protein calculations, i.e., Thr requirements should be 70% of lysine requirements for chicks 3 to 8 wk of age.

A review and comparison of feedstuff amino acid digestibility values for poultry and swine is presented and the use of amino acid digestibility and availability is discussed. The effect of overprocessing on amino acid digestibility of oilseed meals is also reviewed. In general, true digestible amino acid values determined in cecectomized roosters are 5–10% higher than apparent digestibility values determined in ileal-cannulated pigs. Several studies have shown beneficial responses to formulating diets based digestible amino acid values vs. total amino acid values. However, feedstuff amino acid digestibility values determined via balance assays are often higher than amino acid availability values determined by slope-ratio growth assays. In addition, recent work with pigs suggests that the ileal digestibility assay overestimates the amount of amino acids available or utilizable for protein synthesis. Finally, overprocessing of oilseed meals greatly reduces the amount of digestible or available lysine, whereas other amino acids are usually much less affected. Protein solubility in KOH is a good in vitro assay for detecting decreased protein quality due to overprocessing and the use of Coomassie Blue dye simplifies and reduces the time required to conduct the assay.

Three experiments were conducted with commercial broiler chicks to determine the SAA requirement during the growth period 3 to 6 wk posthatching. A 20% CP corn-peanut meal basal diet (3,200 kcal ME(n)/kg) was analyzed to contain 0.23% Met and 0.28% cystine. True digestibility assessment in cecectomized cockerels revealed that Met and cystine in the basal diet were 81 and 75% digestible, respectively. Therefore, the basal diet contained 0.19% digestible Met and 0.21% digestible cystine. When fully fortified with DL-Met, growth rate and feed efficiency of chicks fed the corn-peanut meal diet were equal to that of chicks fed a 20% CP Met-fortified corn-soybean meal diet. In the SAA requirement assay, Ross x Hubbard male chicks were fed graded increments of DL-Met (0.03%) and L-cystine (0.03%) to achieve digestible SAA concentrations of 0.40, 0.46, 0.52, 0.58, 0.64, and 0.70%. Weight gain and feed efficiency responded quadratically (P < 0.01) to increasing doses of SAA. The estimated requirement for maximal feed efficiency was higher than that for maximal weight gain. Both visual appraisal and curve fitting procedures suggested a requirement of close to 0.61% digestible SAA. When extrapolated to a corn-soybean meal diet where SAA true digestibility is 87.5%, the total SAA requirement calculates to be 0.70% of the diet. However, because commercial corn-soybean meal diets typically contain supplemental Met, which is only 81% efficient (wt:wt) in furnishing cystine, the estimated total SAA requirement for chicks fed 20% CP Met-fortified corn-soybean meal diets with 3,200 kcal of ME/kg would probably approximately 0.72% of the diet. A DL-Met vs L-cystine supplementation assay suggested that digestible cystine can supply no more than 52% of the total requirement for digestible SAA of chicks during the 3- to 6-wk growth period.

Two experiments were conducted to evaluate the effects of overprocessing by autoclaving on the in vivo protein quality and in vitro protein solubility in 0.2% KOH of solvent-extracted peanut meal containing 48% protein. The peanut meal was autoclaved at 120 C and 105 kPa for 0, 20, 30, 40, 50, 60, or 90 min. In vivo protein quality of the autoclaved peanut meal was evaluated in chicks fed corn-peanut meal diets (22.5% protein) from 8 to 22 d of age and in adult cecectomized roosters using a precision-fed amino acid digestibility assay. Chick performance was significantly decreased when peanut meal had been autoclaved (P < 0.05) 60 min or more in one experiment and by 40 min or more in the other experiment. True digestibility of amino acids in peanut meal also decreased as autoclaving time increased. The effect of autoclaving was greatest for lysine, wherein digestibility was 87, 72, 68, and 57% for peanut meal autoclaved for 0, 30, 60, or 90 min, respectively. Protein solubility of peanut meal in 0.2% KOH decreased from 78 to 56% as autoclaving time increased from 0 to 90 min. Protein solubility values of 70% or lower were indicative of decreased in vivo peanut meal quality. The results of this study indicated that overprocessing by autoclaving reduces the protein quality of peanut meal and that protein solubility in KOH is a useful in vitro index of overprocessing.

Previous research showed that formulation of chick diets containing cottonseed meal (CSM) using true digestible amino acid (AA) values was superior to formulation based on total AA; however, optimum growth performance could not be obtained from high CSM diets even when formulated on a digestible AA basis. Therefore, two experiments were conducted to determine whether the digestible AA in CSM were totally bioavailable or utilizable for protein synthesis. Soybean meal (SBM) was also evaluated for comparison. True digestibility of Lys and Val in CSM and SBM were determined using the precision-fed cecectomized rooster assay. Bioavailability was then assessed by chick growth assay using purified crystalline AA diets deficient in Lys or Val that were supplemented with varying levels of the test AA, CSM,SBM, or AA mixtures simulating the digestible AA composition of CSM and SBM. Multiple regression slope-ratio methodology indicated that bioavailability of the digestible Lys in CSM and the digestible Lys and Val in SBM did not differ (P > 0.05) from 100% for most response parameters. Bioavailability of the digestible Val in CSM ranged from 78 to 96% depending on response parameter. Bioavailabilities of crystalline Lys and Val in the AA mixtures simulating CSM and SBM were generally lower than the bioavailabililties of the digestible Lys and Val in CSM and SBM. The results of this study indicated that the digestible Lys and Val in SBM and CSM as measured by the precision-fed cecectomized rooster assay are totally or almost totally bioavailable for protein synthesis.

The nutritive value of high-fat yeast (HFY; Cryptococcus curvatus ) was evaluated in two experiments. In Experiment 1, chicks were used to compare effects of supplemental fat from HFY or tallow on growth performance and fatty acid composition of breast and thigh muscles. In Experiment 2, adult cockerels were used to determine the true metabolizable energy value of HFY. Feeding HFY did not exert any negative effects on thick performance and it improved feed efficiency by 6% over a control (no added fat) diet. However, chicks gained more slowly and had lower gain/feed when HFY replaced tallow in the diet. Chicks fed HFY had a lower proportion of oleic acid in breast and thigh muscles, despite the higher proportion of oleic acid in HFY than tallow. True metabolizable energy of HFY was much lower than anticipated and suggests that the digestibility of fat from HFY was low. Physical or chemical treatment of HFY seems necessary to enhance the energy value of HFY as a potential animal feed supplement.

Nitrogen-corrected true metabolizable energy (TMEn) and true amino acid digestibility values were determined, using cecectomized cockerels, for 20 sorghum [Sorghum bicolor (L.) Moench] cultivars that ranged in catechin equivalent (CE) percentages from 0 to 3.88. There were significant (P ≤ 0.01) overall inverse relationships between CE content and (1) the individual digestibilities of lysine, methionine, threonine, isoleucine, leucine, valine, phenylalanine, histidine, and arginine; (2) the mean digestibility of essential amino acids; (3) the mean digestibility of nonessential amino acids; and (4) TMEn values. In contrast to these overall trends, several cultivars of similar condensed tannin content had markedly different nutrient digestibilities. The dissimilarity of protein digestibilities in sorghum genotypes of similar tannin content was confirmed by subjecting samples of the ground grains to in vitro pepsin digestion with subsequent visualization of the undigested proteins by SDS−PAGE. The present wo...

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 (P0.01) 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 (P0.05) 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 (P0.01) 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 (P0.05) 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.

The results of previous experiments indicated that performance of chicks fed corn-cottonseed meal (CSM) diets was inferior to performance of chicks fed a corn-soybean meal (SBM) diet and that true digestibilities of amino acids (AA) in CSM were lower than those in SBM. Therefore, the current study evaluated the formulation of diets containing expander-solvent CSM on an equivalent total AA basis vs an equivalent digestible AA basis compared to a corn-SBM diet. True digestibility of AA in the CSM, corn, and SBM were determined using the precision-feeding assay, with cecectomized roosters and TMEn was determined using conventional roosters. One-week-old male chicks were then fed diets containing corn and SBM only or diets containing increasing levels of CSM from 5 to 40% that were formulated to be equal in total or digestible AA to the corn-SBM diet. All diets contained 20.7% CP and 3,200 kcal TMEn/kg. Weight gain and feed efficiency of chicks fed 20% or more CSM on a total AA basis were less (P < .05) than those of chicks fed the corn-SBM diet. Growth performance of chicks fed up to 20% CSM on a digestible basis was equivalent to that of chicks fed the corn-SBM diet, but dietary levels of 30 or 40% CSM depressed performance even on a digestible basis. Increasing most essential AA by 15% in the 40% CSM (digestible basis) diet had no effect on performance. True digestible AA and ME values determined in chicks were similar to those determined in roosters. These results indicate that formulation of diets containing CSM on a digestible AA basis is superior to formulation on a total AA basis and that at least 20% CSM could be fed to chicks if the diet contains adequate levels of digestible AA and Fe to bind gossypol. The results also indicated that the depression in performance from feeding 30 or 40% CSM diets was not associated with dietary AA levels.

Glucosinolates and their breakdown products (nitriles) have long been implicated as toxic factors when feeding rapeseed (Brassica napus) meals and crambe (Crambe abyssinica) meals to poultry. Accordingly, various methods have been developed to remove these compounds from the meals to enhance their value as feed supplements. Glucosinolates and nitriles were extracted from commercially processed, defatted crambe meal by washing with water or various solvent-water mixtures: 50% isopropanol, 50% acetone, or 50% ethanol. In addition, crambe seed was extruded and extracted in the laboratory with isopropanol or hexane. Water washing of commercially defatted meal proved to be the most effective method of extraction, removing 95% of the glucosinolates and nitriles. Meals were fed to 7-d-old broiler chicks at 10% of the diet for 14 d. Weight gain decreased (P < .05) in most groups; however a greater decrease (P < .01) was observed in birds fed meals with high glucosinolate content. Feed intake also decreased (P < .05) in most groups; consequently, feed efficiencies were similar for all groups. No changes in serum chemistries, triiodothyronine, thyroxine, or tissue lesions were associated with glucosinolate or nitrile intake. A relationship (P < .05, r = .74) was found between weight gain and glucosinolate intake. No correlation was found between feed intake and meal glucosinolate or nitrile concentrations.

The effects of abrupt dietary energy changes on daily feed and caloric intake during the transition from the pullet to the layer programs and on subsequent layer performance were investigated in two experiments. In Experiment 1, birds were fed pullet diets containing 2943, 3113, or 3187 kcal TMEn/kg from 11 through 18 wk of age and then fed layer diets containing either 2829 or 2943 kcal TMEn/kg from 18 through 34 wk. In Experiment 2, birds were fed pullet diets containing either 2863 or 3259 kcal TMEn/kg from 11 through 18 wk of age and then fed layer diets containing 2845, 2958, or 3073 kcal TMEn/kg from 18 through 34 wk. Within two to three days following the change from pullet to layer diets, birds adjusted their feed intakes so that daily caloric intakes were similar among treatments in most cases. The results indicate that 18-wk-old pullets adapt rapidly to abrupt dietary energy changes when switched from pullet grower diets to layer diets.

A 2-wk chick study was conducted to evaluate the effect of overprocessing on the in vivo nutritional quality and in vitro protein solubility in .2% KOH of solvent-extracted sunflower meal (SFM) containing 36% protein. The SFM was autoclaved at 121 C and 105 kPa for 0, 30, 60, or 90 min in Experiment 1 and for 0, 10, 20, 30, 40, or 60 min in Experiment 2. Corn-SFM diets containing 22% protein were fed to chicks from 8 to 17 d of age. Chick performance decreased in both experiments as autoclaving time of the SFM increased. Linear regression analysis of performance on autoclaving time yielded the equations Y = 126.7 − .32× (r2 = .94) for weight gain and Y = .615 − .001× (r2 = .80) for feed efficiency in Experiment 1. A precision-fed cockerel digestibility assay using cecectomized birds indicated that true digestibility of amino acids in SFM decreased as autoclaving time increased. The effect of autoclaving on digestibility was greatest for Lys, wherein Lys digestibility in SFM was 86, 54, 43, and 35% when SFM was autoclaved for 0, 30, 60, or 90 min, respectively. Protein solubility of SFM in .2% KOH decreased from 64 to 51% as SFM was autoclaved from 0 to 60 min. The results indicated that protein solubility values of 60% or lower are indicative of overprocessing of SFM.

The objective of this study was to evaluate and compare amino acid digestibility of several feedstuffs using 2 commonly accepted methods: the precision-fed cecectomized rooster assay (PFR) and the standardized ileal amino acid assay (SIAAD). Six corn, 6 corn distillers dried grains with or without solubles (DDGS/DDG), one wet distillers grains, one condensed solubles, 2 meat and bone meal (MBM) and a poultry byproduct meal were evaluated. Due to insufficient amounts, the wet distillers grains and condensed solubles were only evaluated in roosters. Standardized amino acid digestibility varied among the feed ingredients and among samples of the same ingredient for both methods. For corn, there were generally no differences in amino acid digestibility between the 2 methods. When differences did occur, there was no consistent pattern among the individual amino acids and methods. Standardized amino acid digestibility was not different between the 2 methods for 4 of the DDG samples; however, the PFR yielded higher digestibility values for a high protein DDG and a conventionally processed DDGS. The PFR yielded higher amino acid digestibility values than the SIAAD for several amino acids in 1 MBM and the poultry byproduct meal, but it yielded lower digestibility values for the other MBM. Overall, there were no consistent differences between methods for amino acid digestibility values. In conclusion, the PFR and SIAAD methods are acceptable for determining amino acid digestibility. However, these procedures do not always yield similar results for all feedstuffs evaluated. Thus, further studies are needed to understand the underlying causes in this variability.

Chicks were used to determine whether dietary corn distillers dried grains with solubles (DDGS) may prevent or ameliorate Eimeria acervulina (EA) infection. The experiment had a completely randomized design with a factorial arrangement of 3 diets (inclusion of 0, 10, or 20% DDGS) × 2 challenge treatments: inoculation with distilled water or with 10(6) sporulated EA oocysts. Each treatment was replicated with 8 pens of 5 chicks each. Experimental diets were fed from 7 to 21 d of age. Inoculation occurred on d 10 of age, considered postinoculation (PI) d 0. Feed intake and BW were measured on PI d 0, 7, and 14. Excreta samples were collected on PI d 0, 5 to 10, 12, and 14 to detect oocysts. On PI d 14, mucosal samples were collected for the analysis of bacterial populations by denaturing gradient gel electrophoresis, using the V3 region of bacterial 16S ribosome. The EA challenge reduced (P < 0.001) ADG by 17%, ADFI by 12%, and G:F by 6% from PI d 0 to 7, and by smaller percentages from PI d 7 to 14. Diet and challenge treatments did not interact in the chick performance, so dietary DDGS did not alleviate EA infection. Oocysts in excreta were detected PI only in EA chicks and no dietary effects were found. Cecal bacterial population was changed (P < 0.05) by effect of dietary DDGS and EA infection. The cecal bacterial diversity among chicks within treatments and homogeneity among chicks within treatments were reduced by EA infection (P = 0.02 to 0.001) and increased by feeding 10% DDGS (diet quadratic, P < 0.001). In summary, feeding up to 20% DDGS to young chicks did not prevent or ameliorate EA infection. Changes in cecal microbiota of chicks fed 10% DDGS can be interpreted as beneficial for intestinal health.

The objective of these studies was to develop a precision-fed ileal digestibility assay, primarily for amino acids (AA), using 3-wk-old broiler chicks. For all experiments, day-old Ross × Ross 708 broiler chicks were fed a standard corn-soybean meal starter diet until 21 d of age. In experiment 1, feed was removed and excreta were collected at 2, 4, 6, 8, 10, 12, and 14 h after feed withdrawal. Results indicated that 8 h of feed withdrawal was sufficient to empty the ileum of feed residues. In a subsequent experiment, chicks were fasted overnight for 10 h and then tube-fed various amounts (from 6 to 15 g) of a corn-soybean meal mixture (60:40). Ileal digesta from Meckel's diverticulum to the ileo-cecal junction were then collected at various collection times between 3 and 7 h postfeeding. Results indicated that the amount of digesta in the distal ileum was generally maximized by 4 h postfeeding and by feed intakes of 9 g or greater. Based on the results of the previous study, apparent and standardized ileal digestibility values of AA in a corn-soybean meal chick starter diet were then determined at 2, 3, and 4 h postfeeding. Digestibility values were similar for the 3- and 4-h collection times, but were numerically or significantly (P ≤ 0.05) lower at the 2-h collection time. The results of this study indicate that ileal AA digestibility can easily be determined in 3-wk-old broiler chicks when using a precision-fed assay. For such an assay, it is recommended that the chicks be fasted for at least 8 h before tube-feeding, that they be precision-fed approximately 10 g of feed, and that the ileal contents be collected at approximately 4 h postfeeding.