Evaluation of a thermotolerant xylanase on broiler growth performance and dietary ileal digestible energy value

Two experiments were conducted to evaluate the impact of a thermotolerant xylanase on male broiler performance and dietary ileal digestible energy (IDE). The first experiment consisted of 3 treatment groups with 12 replications per treatment each containing 35 Cobb 500 males for a total of 1,260 broilers placed in floor pens for a 42 d grow-out. The experiment treatments included a corn/soy diet with DDGS control formulated at a low energy level, and the control supplemented with one of 2 concentrations of xylanase (20,000 XU/kg [XYL20] and 40,000 XU/kg [XYL40]). No significant differences in body weight were observed with the inclusion of xylanase when compared to the control diet throughout the experiment. At d 28, the inclusion of XYL20 improved (P < 0.05) mortality corrected feed conversion ratio (FCR) compared to the control diet. Feed conversion ratio was also improved (P < 0.01) at d 42 for birds fed XYL20 when compared to the control. At d 42, inclusion of XYL20 and XYL40 significantly (P < 0.05) increased IDE compared to the control. Experiment 2 consisted of 4 treatment groups with 10 replications per treatment each containing 44 Cobb 500 males for a total of 1,760 broilers placed in floor pens for a 41 d grow-out. The dietary treatments included a positive control (PC) based on a corn/soy diet containing DDGS and phytase, a negative control (NC) diet (PC -150 kcal/kg in AME), NC + xylanase at 10,000 XU/kg (XYL10), and NC + xylanase at 20,000 XU/kg (XYL20). A significant increase (P < 0.05) in BW was observed in broilers fed the inclusion of XYL20 in the NC diet increased (P < 0.05) on d 14. A significant increase in cumulative body weight gain was observed on d 27 and d 41 with xylanase (XYL20) inclusion compared to the NC. These data demonstrate that xylanase inclusion increased energy utilization through improvements in IDE, which improved broiler performance.     

Growth,nutrient digestibility,ileal digesta viscosity,and energy metabolizability of growing turkeys fed diets containing malted sorghum sprouts supplemented with enzyme or yeast

Growth, apparent nutrient digestibility, ileal digesta viscosity, and energy metabolizability of growing turkeys fed diets containing malted sorghum sprouts (MSP) supplemented with enzyme or yeast were investigated using 120, 28‐day‐old male turkeys. Six treatments were laid out in a 3 × 2 factorial arrangement of treatments with three dietary inclusion levels of MSP (0, 50, and 100 g/kg) and supplemented with 200 mg/kg yeast (Saccharomyces cerevisiae) or 200 mg/kg of a commercial enzyme. The experiment lasted for the starter (day 28–56) and grower phases (day 57–84) of the birds. Each treatment group consisted of 20 turkeys replicated four times with five birds each. Data were analysed using analysis of variance while polynomial contrast was used to determine the trends (linear and quadratic) of MSP inclusion levels. Irrespective of dietary supplementation with enzyme or yeast, final body weight (BW), total BW gain, and feed intake for turkey poults from day 29–56 was reduced (p < 0.05) with increasing inclusion level of MSP. Dietary supplementation with yeast resulted in increased (p < 0.05) feed intake while enzyme supplementation improved (p < 0.05) feed conversion ratio of the poults. Turkeys fed enzyme‐supplemented MSP diets had higher (p < 0.05) BW gain than their counterparts fed yeast‐supplemented MSP diets. Apparent ash digestibility reduced linearly (p < 0.05) with increasing inclusion levels of MSP. Apparent metabolizable energy (AME) did not vary significantly (p > 0.05) with MSP inclusion levels . Enzyme supplementation reduced (p < 0.05) ileal viscosity but had no effect (p > 0.05) on AME. Inclusion of MSP resulted in poor growth performance. This confirms earlier studies that utilization of MSP by poultry is rather poor. Supplementation with enzyme or yeast did not lead to any appreciable improvement in performance of turkeys in this study.     

Effects of increasing dried distillers’ grains with solubles and non-starch polysaccharide degrading enzyme inclusion on growth performance and energy digestibility in broilers

Two experiments were conducted to examine the effects of non-starch polysaccharide degrading enzyme on broiler performance and ileal nutrient digestibility in diets containing dried distillers’ grains with solubles, as well as evaluate non-starch polysaccharide degrading enzyme inclusion in low energy diets with dried distillers’ grains with solubles on performance and carcass yield. Experiment 1 was a 4 (dried distillers’ grains with solubles level of 0, 5, 10, and 15%) x 2 (with and without enzyme) factorial design in battery-reared broilers for 21 d; body weights and feed intake were determined weekly. On day 22, ileal contents were collected to determine digestibility of energy and nitrogen. The second experiment was a 48 d floor pen trial utilizing three dietary treatments: positive control, negative control (positive control, negative control less 132 kcal/kg ME), and a negative control + non-starch polysaccharide degrading enzyme inclusion. Diets included dried distillers’ grains with solubles at 2.5 to 10%. In Experiment 1, BW decreased (P < 0.05) with 15% dried distillers’ grains with solubles inclusion as compared to the control. The FCR was also increased (P < 0.05) with 15% dried distillers’ grains with solubles inclusion as compared to all other diets through 14 d. Inclusion of dried distillers’ grains with solubles reduced (P < 0.05) ileal digestible energy at 10 and 15% inclusion and inclusion of non-starch polysaccharide degrading enzyme increased (P < 0.05) ileal digestible energy. Increased energy and nitrogen digestibility coefficients (P < 0.05) were observed at all dried distillers’ grains with solubles inclusion levels with non-starch polysaccharide degrading enzyme inclusion except for the 10% inclusion rate. In Experiment 2, non-starch polysaccharide degrading enzyme in the negative control diet increased BW compared to the negative control at all observed time points at each phase (P < 0.05). Additionally, non-starch polysaccharide degrading enzyme in the negative control diet reduced mortality corrected FCR through the grower phase. Non-starch polysaccharide degrading enzyme inclusion in the negative control diet resulted in comparable live weights, carcass weights, breast filets, and tenders to the positive control diet; however, fat pad was reduced compared to the positive control (P < 0.05). These data confirm that elevated levels of dried distillers’ grains with solubles in starter diets can negatively impact digestibility and performance of broilers and the inclusion of an non-starch polysaccharide degrading enzyme can increase nutrient digestibility and improve broiler performance in low energy dried distillers’ grains with solubles containing diets.     

Effect of feeding a pellet diet containing high sulphur with fresh cassava root supplementation on feed use efficiency,ruminal characteristics and blood metabolites in Thai native beef cattle

The objective of this experiment was to study the effect of feeding pellet containing high sulphur (PELFUR) diet and fresh cassava root (FCR) to Thai native beef cattle on feed use efficiency, ruminal characteristics and blood metabolites. Four male purebred Thai native beef cattle (1.5–2.0 years old) with initial body weight (BW) of 150 ± 15.0 kg were allocated with a 2 × 2 factorial arrangement in a 4 × 4 Latin square design. Factor A was FCR supplementation at 15 and 20 g/kg of BW. Factor B was the sulphur level in the PELFUR ration at 15 and 30 g/kg of dry matter (DM). No interaction effect was found among FCR supplementation and PELFUR in terms of feed intake and nutrient intake (p > 0.05). Cyanide intake was significantly increased based on FCR supplementation (p < 0.05), whereas sulphur intake was increased by level addition of PELFUR levels (p < 0.05). There were interaction effects among FCR supplementation and PELFUR on digestibility coefficients of DM and organic matter (OM) (p < 0.05). FCR supplementation at 20 g/kg BW with PELFUR 30 g/kg demonstrated the highest digestibility of DM and OM. Moreover, interactions were observed between FCR and PELFUR for bacterial populations (p < 0.01). The populations of bacteria were highest in FCR supplementation at 20 g/kg BW with PELFUR 30 g/kg at various feeding times. An interaction effect from among feeding FCR with PELFUR was found on blood thiocyanate concentrations at various feeding times (p < 0.01). The highest mean values of blood thiocyanate were observed when feeding FCR at 20 g/kg BW with PELFUR at 30 g/kg. No interaction effect was found between FCR and PELFUR on total volatile fatty acids (VFA) and their profiles (p > 0.05). However, the proportions of the total VFA at 0 and 4 h post-feeding were increased when FCR at 20 g/kg BW was supplemented (p < 0.01). FCR at 20 g/kg BW could enhance propionate (C3) at 4 h post-feeding when compared with FCR at 15 g/kg BW (p < 0.01). Moreover, supplementation of PELFUR at 30 g/kg increased the total VFA at 0 and 4 h post-feeding, whereas the concentration of C3 at 4 h post-feeding was enhanced (p < 0.05). However, no significant changes were found for any parameters among treatments and between the main effect of FCR and PELFUR supplementation (p > 0.05). In conclusion, feeding of two combinations (FCR 20 g/kg BW with PELFUR 30 g/kg) could promote the nutrient digestibility, the bacterial populations and the rate of disappearance of cyanide without having any adverse effect on rumen fermentation.     

Effects of high fat,modified wet,corn distiller's grains plus solubles on beef steer performance and carcass characteristics

Corn distiller's grains plus solubles (DGS) have become a common replacement for shelled corn in diets of finishing steers. Numerous studies have evaluated DGS inclusion, both wet (WDGS) and dry (DDGS), into feedlot diets with conflicting reports on feedlot performance and subsequent meat quality. Many authors have failed to describe the nutrient composition of the DGS utilized in their studies making it difficult to determine why different studies have different results. The objective of this study was to evaluate the feedlot performance and subsequent meat quality characteristics of steers fed high fat (10.36±0.72%), modified wet corn distiller's grains plus solubles (HWDGS) at 0, 25, 40, and 70% of the diet dry matter (DM). Angus cross steers (n=240; 335±55 kg) were blocked by source and stratified within block (3 blocks) by body weight (BW) to 32 treatment pens containing either 6 or 10 steers/pen. Pens within block were randomly assigned to one of four diets containing 15% corn silage: (1) 76.9% shelled corn, 6.4% soybean meal 1.5% limestone, 0.2% premix (0 HWDGS); (2) 25.0% HWDGS, 58.20% shelled corn 1.6% limestone, 0.2% premix (25 HWDGS); (3) 40.0% HWDGS, 42.74% shelled corn 2.06% limestone, 0.2% premix (40 HWDGS); (4) 70.0% HWDGS, 12.30% shelled corn 2.5% limestone, 0.2% premix (70 HWDGS). Target BW at harvest was 591 kg±23 kg with 121 steers harvested on day (d) 161 and 117 steers on d 224. Hot carcass weight and liver abscess scores were recorded on d of harvest. Longissimus muscle area, rib fat thickness, marbling score, and kidney, pelvic and heart fat were measured after a 24 h chill. No significant differences were observed between treatments regarding average daily gain (ADG) or BW. Steers fed 0 HWDGS had significantly lower average daily feed intake (ADFI) than steers fed HWDGS and the response was quadratic at lower ADFI. Steers fed 70 HWDGS had lower (P<0.05) dry matter intake (DMI) compared to steers fed lower HWDGS concentrations. Steer gain to feed ratio (G:F) was significantly higher for steers fed 70 HWDGS compared to 0, 25, or 40 HWDGS with a quadratic response at higher % HWDGS diets. Mean United States Department of Agriculture (USDA) quality grade was average choice. Mean USDA yield grade was 3.0. Steers fed 70 HWDGS had significantly smaller rib eye areas and a linear trend (P=0.08) to have lower USDA quality grades compared to steers fed lower HWDGS inclusion rates. Increasing dietary HWDGS increased polyunsaturated fatty acid (PUFA) and PUFA/saturated fatty acid concentrations in intramuscular fat with both a linear and quadratic effect. High fat modified WDGS can be fed up to 70% of diet DM without compromising feedlot performance, carcass characteristics, or meat quality.     

Evaluation of beta-mannanase and nonstarch polysaccharide-degrading enzyme inclusion separately or intermittently in reduced energy diets fed to male broilers on performance parameters and carcass yield

The experimental design consisted of 5 dietary treatments including a positive control (PC), a negative control (NC; with a reduction of 88 kcal/kg of AME through the starter and grower 1 phase and a reduction of 132 kcal/kg of AME in the grower 2, finisher, and withdrawal phases compared with the PC), and the NC supplemented with either β-mannanase, nonstarch polysaccharide-degrading enzymes (NSPase; cocktail carbohydrase), or β-mannanase and NSPase intermittently fed. The intermittent treatment included β-mannanase from d 1 to 21 (starter and grower 1 phases) and NSPase from d 22 to 47. Each treatment included 9 replicate pens with 35 male broilers placed per replicate (1,575 total chicks placed). The dietary program consisted of 5 dietary phases, including the starter through d 10, grower 1 through d 21, grower 2 through d 32, finisher through d 40, and withdrawal through d 47. Broilers were weighed and feed consumption determined on days of dietary changes. On d 48, following an 8-h feed withdrawal, 6 broilers from each replicate pen were removed and processed for whole bird and fat pad measurements. The reduction in energy in the NC diet reduced BW and increased mortality rate, and the inclusion of β-mannanase and NSPase separately and intermittently in the NC diet improved growth performance and reduced mortality to levels that were comparable to the PC. The NC yielded the highest cumulative mortality-corrected FCR and all enzyme inclusion treatments reduced FCR to levels comparable to the PC for the duration of the trial. The NC diet yielded the lowest processing yields and the inclusion of β-mannanase and NSPase separately and intermittently increased multiple processing parameters to a level similar to the PC. These data confirm the ability of β-mannanase and NSPase inclusion separately and intermittently to improve performance parameters in reduced-energy broiler diets.     

Effect of cereal type and Xylanase supplementation on nutrient retention and growth performance of broilers

An experiment was conducted to study the effect of cereal (corn, wheat, barley and sorghum) and supplemental enzyme (a mono-component xylanase) in a 4 × 2 factorial arrangement. A 2-phase feeding program (0 to 21 and 21 to 42 d) was used and 4 iso-caloric, iso-nitrogenous diets were formulated containing corn, wheat, barley, or sorghum as the sole cereal. Diets based on each cereal were fed without or with supplemental xylanase (16,000 BXU/kg) to 8 replicate pens of 10 chicks (5 male : 5 female, Cobb 500) each. Growth performance was recorded at 21 or 42 d posthatch. Excreta was quantitatively collected from 18 to 21 and 38 to 41 d for the measurement of the total tract retention of dry matter (DM), nitrogen (N) and neutral detergent fiber (NDF) and apparent metabolizable energy (AME). Ileal digestible energy (IDE) was measured at the end of the study (42 d posthatch) using titanium dioxide as an indigestible marker. For the overall 42 d period, birds fed barley-based diets had lower feed intake (P < 0.05), lower body weight (P < 0.05) and converted feed into gain less efficiently (P < 0.05) compared with the diets based on corn, wheat or sorghum. Xylanase supplementation improved weight gain in diets based on corn, wheat, and sorghum with the exception of barley-based diets (cereal × xylanase interaction, P < 0.05). Xylanase improved the overall feed conversion ratio (1.885 vs. 1.939; P < 0.05) with the effect being independent of the cereal type. The N retention of barley-based diets was lower (P < 0.05) compared with the other cereals, while xylanase improved N retention (P < 0.05) regardless of the cereal type. NDF digestibility differed (P < 0.05) across cereal (barley > wheat > corn > sorghum) and was improved (P < 0.05) by xylanase supplementation. A significant cereal × xylanase interaction (P < 0.05) was observed for energy measurements, where xylanase improved IDE of the corn-based diet, and AME of corn- and wheat-based diets. Results of the current study demonstrate potential of xylanase in improving nutrient retention and growth performance of broilers fed diets based on variety of cereal grains.     

Influence of partial replacement of ground wheat with whole wheat and exogenous enzyme supplementation on growth performance,nutrient digestibility and energy utilization in young broilers

This study investigated the influence of pre‐pelleting inclusion of whole wheat (WW) and exogenous enzyme supplementation on growth performance, coefficient of apparent ileal nutrient digestibility (CAID) and apparent metabolizable energy (AME) in broilers fed wheat‐based pelleted diets. A 2 × 3 factorial arrangement of treatments was used with two methods of wheat inclusion [622 g/kg ground wheat (GW) and 250 g/kg WW replaced GW (wt/wt) pre‐pelleting (PWW)] and three enzymes (xylanase, phytase and xylanase plus phytase). A total of 288, one‐day‐old male broilers (Ross 308) were individually weighed and allocated to 36 cages (8 broilers/cage), and the cages were randomly assigned to the six dietary treatments. Birds fed PWW diets gained more (p < 0.05) weight than those fed GW diets. There was no effect (p > 0.05) of WW inclusion on feed intake (FI). Phytase alone increased (p < 0.05) FI compared to xylanase or the combination. Whole wheat inclusion increased (p < 0.05) the gain‐to‐feed ratio (G:F). Feeding xylanase plus phytase and phytase‐added diets resulted in the greatest and lowest G:F, respectively, with xylanase supplemented diets being intermediate. Birds fed PWW diets had greater (p < 0.05) relative gizzard weights than those fed GW diets. There was no effect (p > 0.05) of WW inclusion on the CAID of nitrogen (N), starch and fat. Combination of xylanase and phytase resulted in greater (p < 0.05) digestibility of N, starch and fat than that of individual additions. Feeding PWW diets resulted in greater (p < 0.05) AME values than GW diets. Combination of xylanase and phytase increased (p < 0.05) the AME compared to the diets with individual additions of xylanase or phytase. The current results suggest that the influence of pre‐pelleting WW inclusion and exogenous enzymes on nutrient digestibility and broiler performance is not additive.     

Effects of feeding cracked corn and concentrate protein pellets on broiler growth performance

Typically, in a vertically integrated poultry (broiler or turkey) operation, maintaining adequate feed manufacturing production proves to be a challenge. To evaluate an alternative management strategy, 2 studies were conducted to examine the effects of feeding broilers cracked corn and a concentrated pellet on broiler growth performance from 0 to 41 d of age. Cracked corn (0, 25, 50, 75, or 100%) was used to replace the corn fraction in the diet for all 3 stages of growth. Cracked corn and concentrate pellets were blended together to be isonitrogenous and isocaloric among all treatments, so only feed form would differ. Experiment 1 diets included a control (0% cracked corn) and experimental diets (25, 50, 75, or 100%) in which cracked corn directly replaced the ground corn fraction. Overall (0 to 41 d), a linear decrease (P < 0.001) for ADG and ADFI and a linear increase (P < 0.003) for FCR was observed as cracked corn levels increased. In experiment 2, a “step-up” feeding program of cracked corn was evaluated with dietary treatments including the following: 1) control (0% cracked corn throughout feeding), 2) 0% cracked corn (0 to 17 d) and 25% (18 to 41 d), 3) 0% cracked corn (0 to 17 d) and 50% (18 to 41 d), 4) 25% cracked corn (0 to 41 d), and 5) 50% cracked corn (0 to 41 d). Overall (0 to 41 d), ADG for treatment 1, 2, and 4 was greater than 3 and 5 (P < 0.05). Feed conversion ratio was superior for treatments 2 and 4 (P < 0.05) in comparison with treatments 3 and 5. Up to 25% of the dietary corn can be fed to the broiler as cracked corn from 0 to 41 d without a negative response on growth performance.     

Effect ofBacillus amyloliquefaciens-based direct-fed microbials and antibiotic on performance,nutrient digestibility,cecal microflora,and intestinal morphology in broiler chickens

Two hundred eighty-eight 1-d-old male Arbor Acres broilers were randomly allocated to 4 treatments to examine the effect of usingBacillus amyloliquefaciens-based direct-fed microbials (DFM) to replace antibiotics in the late growth stage on performance, nutrient digestibility, cecal microflora, and intestinal morphology in broilers. The experimental diets were (1) a negative control (NC) group fed a basal diet without any antibiotics; (2) a positive control (PC) group fed the basal diet with 200 mg/kg of zinc bacitracin; (3) a test group fed the basal diet with 200 mg/kg of zinc bacitracin from d 1 to 21 and 30 mg/kg of DFM from d 22 to 42 (DFM30); and (4) a test group fed the basal diet with 200 mg/kg of zinc bacitracin from d 1 to 21 and 60 mg/kg of DFM from d 22 to 42 (DFM60). The results showed that DFM30 and DFM60 increased BW gain and improved FCR as compared with NC group (P < 0.05). Generally, the PC, DFM30, and DFM60 groups showed increased apparent total tract nutrient digestibility for DM, CP, and AME as compared with the NC group. Both the DFM30 and DFM60 groups decreased cecalEscherichia coli population as compared with the NC group, and increased the population ofLactobacillus as compared with the PC group. The PC, DFM30, and DFM60 groups increased villus height and the ratio of villus height to crypt depth compared with NC. In conclusion, dietary supplementation withB. amyloliquefaciens-based DFM during d 22 to 42 may enhance performance by increasing nutrient digestibility and improving intestinal health in birds fed diets supplemented with zinc bacitracin from d 1 to 21.     

Interactive effect of corn particle size and insoluble fiber source on performance,nutrient utilization and intestine morphology in broilers fed pelleted diets

The effects of corn particle size and dietary fibre on the performance, coefficient of apparent ileal digestibility (CAID) and intestinal characteristics in broiler starters fed pelleted diets were studied. The experiment included 10 treatments arranged as a 2 × 5 factorial with two corn particle sizes (GMD of 1071 [CGC] vs. 534 [FGC]) and five diets that consisted in a low-fibre diet and four extra diets resulting from the inclusion of insoluble fibre sources (10 g/kg of lignocellulose (LC), and 30 g/kg of oat hulls; OH, rice hulls; RH, and sunflower hulls; SFH). In coarse grinding, all-fibre sources improved body weight gain and feed intake compared to the control diet (p < 0.01). Feed conversion ratio (FCR) improved with fibre supplementation (p < 0.01) and fine grinding of corn (FGC) (p < 0.01). Coarse grinding of corn (CGC) and inclusion of RH, SFH and OH reduced gizzard pH (p < 0.01). Fibre inclusion increased ileal fat and Ca digestibility (p < 0.01), gizzard weight (p < 0.01), digesta transit time (p < 0.01) and length of duodenum and small intestine (p < 0.01). The CAID of phosphorus increased in CGC fed birds and inclusion of RH, SFH and OH (p < 0.05). The weight of gizzard, proventriculus and pancreas (p < 0.01) was greater in CGC fed birds. Feeding SFH, RH and OH (p < 0.01), and CGC (p < 0.01) increased the villus height (VH) of the duodenum. The OH, RH and SFH supplementation increased the caecal population of Lactobacillus spp. and total anaerobic bacteria (p < 0.01) only in FGC fed birds. Overall, birds fed pelleted diets containing RH, OH and SFH (3%) exhibited improved performance, and increased nutrient digestibility, which may be caused by developed gizzards and intestine. Furthermore, coarse grinding of corn is beneficial to gizzard development.     

Evaluation of xylanase in low-energy broiler diets

The objective of the current study was to evaluate the effect of feeding a thermo-tolerant xylanase in low-energy broiler diets on performance and processing parameters. Evaluation criteria included average broiler BW, FCR, livability, carcass yield, and fat pad yields. The experimental design consisted of 3 nutrient profiles: positive control, negative control 1 (−66 kcal/kg), and negative control 2 (−132 kcal/kg). Two xylanase inclusion programs were included in the negative control 1 and 2 diets; 60 g/t was included in the starter and grower diets with either 60 or 100 g/t in the finisher and withdrawal diets, yielding a total of 7 treatment groups with 8 replicate pens per treatment each containing 42-d-old straight-run chicks per treatment (2,352 total broilers). Broilers were reared in floor pens through 45 d of age. The dietary program consisted of 5 dietary phases: starter (1–15 d), grower 1 (16–23 d), grower 2 (24–31 d), finisher (32–38 d), and withdrawal (39–45 d). Body weights and feed consumption were determined on days of dietary changes, including d 15, 23, 31, 38, and 45. On d 45, 4 male and 4 female broilers per replicate (448 total) were subjected to an 8-h feed withdrawal period and processed to obtain carcass and fat pad weights. Reducing the dietary energy level increased FCR and decreased the fat pad weight of broilers in the negative control 2 treatment compared with the positive control. Inclusion of xylanase during the starter phase increased d 15 BW and reduced FCR. The inclusion of xylanase continued to reduce FCR throughout the trial, as compared with diets without xylanase inclusion. Within this study, we have demonstrated the effectiveness of xylanase inclusion in reduced-energy diets (−66 and −132 kcal/kg) to improve FCR of broilers to that of broilers fed energy-adequate diets.     

Effect of energy and protein levels on performance,egg quality,and nutrient digestibility of laying pigeons

A total of 3,240 female Taisheng pigeons at 40 wk age were fed 9 diets containing 3 ME levels (2,630, 2,770, and 2,940 kcal/kg) and 3 CP levels (14.0, 15.0, and 16.0%) in a factorial arrangement. These diets were fed to investigate the effects of ME and CP on performance, egg quality, and nutrient digestibility. Female pigeons were housed under the same managerial conditions and randomly assigned into 9 treatments (6 replicates of 60 birds each). Two female–female paired pigeons housed in one cage were under a 16L:8D lighting cycle. Feed in pellet form and water were provided for ad libitum consumption. The study lasted 12 wk. As dietary ME level increased from 2,630 to 2,940 kcal/kg, BW, egg production, and apparent DM, crude fat (CF), and phosphorus (i.e., P) digestibilities increased (P < 0.05), feed intake decreased (P < 0.05), and feed conversion efficiency increased (P < 0.05). Increasing the level of dietary protein from 14 to 16% resulted in an increased (P < 0.05) BW, shell percentage, length of the major axis, and DM digestibility. Therefore, dietary ME had a greater influence on the performance of Taisheng laying pigeons than did dietary protein.     

Apparent Metabolizable Energy Needs of Broilers from Two to Four Kilograms as Influenced by Ambient Temperature

During winter production, the optimum temperature set points for heavy broilers (>3.4 kg) approaching market weight are subject to debate in commercial practice. Apparent ME needed to optimize nutrient utilization may be influenced by ambient temperature. This experiment examined potential interactive effects of AME × ambient temperature from 36 to 60 d of age. A 4 × 2 factorial arrangement of treatments was used. Dietary treatments were diets formulated to 3,175, 3,220, 3,265, and 3,310 kcal of AME/kg. Two temperature regimens were provided consisting of variable temperature regimen (VTR) or constant temperature regimen (CTR) set points. The VRT was 21.1°C from 36 to 38 d of age, 20.2°C from 39 to 42 d of age, 18.9°C from 43 to 46 d of age, 17.8°C from 47 to 50 d of age, 15.6°C from 51 to 54 d of age, and 12.8°C from 55 to 60 d of age. The CTR was 21.1°C from 36 to 60 d of age. Significant AME × temperature interactions were observed for cumulative BW, BW gain, feed consumption, feed conversion, and mortality. In the CTR, increasing AME led to increased BW gain but not in the VTR. As dietary AME increased, the improvement in feed conversion was more pronounced in the CTR than the VTR. With the VTR, decreasing AME increased feed consumption. The experimental treatments did not influence abdominal fat percentage or total breast meat yield. These data provide evidence that broilers exposed to CTR respond to increased AME.     

Phytase dose effects in practically formulated diets that vary in ingredient composition on feed manufacturing and broiler performance

Considering approaches to efficiently produce broiler chickens, an experiment was conducted to describe the manufacturing and feeding effects of a corn, soybean meal, and wheat based diet with varying levels of corn distillers dried grains with solubles (DDGS) and commercial phytase. Treatments were arranged in a 3 × 2 factorial randomized complete block design varying in phytase (zero, 1,000, and 6,000 FTU/kg) and DDGS inclusion (zero or 5%). Phytase inclusion decreased dietary non-phytate phosphorous (nPP) and total Calcium (Ca) in formulation by 0.12 and 0.1%, respectively. Diets were steam conditioned at 82°C for 10 s, extruded through a 4.7 × 38 mm pellet die, and fed as crumbles (starter and grower) or pellets (finisher). Ten replicate pens of straight-run Hubbard × Cobb 500 chicks consumed one of 6 dietary treatments for 38 days. Phytase improved feed conversion ratio (FCR) in the starter period (P = 0.05), but benefits were not apparent in the grower or finisher periods. Phytase and formulation main effects interacted to affect overall FCR (P = 0.05), demonstrating a 0.05 decrease in FCR when birds were fed a diet containing a super-dose of phytase and without DDGS relative to diets containing a super-dose of phytase and DDGS. The DDGS likely provided reduced nutrient availability relative to their nutrient values used for diet formulation or provided non-starch polysaccharides (NSP) at a level that decreased bird performance. Based on tibia ash measures, performance improvement associated with the super-dose of phytase was likely associated with reducing phytate phosphorus gastrointestinal irritation rather than meeting bird phosphorus requirement.     

Effect of supplemental zinc source and corn particle size on 40-day broiler performance

Zinc (Zn) supplementation source and particle size of feed ingredients are two factors that can affect poultry performance and should be considered for proper feeding of poultry. The objective of the current study was to assess the effects of Zn supplementation source and corn particle size on broiler performance, breast yield, and tibia Zn concentration. Treatments were arranged in a 5 × 2 factorial randomized complete block design with the main effects Zn treatment and corn particle size (550 micron vs. 1,050 micron). Zinc treatments included a basal diet (no added Zn), 80 mg/kg Zn sulfate, and 3 diets with 40 mg/kg Zn sulfate + 40 mg/kg of either Zn-glycine amino acid (AA) chelate (Zn-gly), Zn-AA complex (Zn-AA), or Zn bis(-2-hydroxy-4-methylthio)butanoic acid (Zn-HMTBA). A total of 8 replications per treatment were fed to 23 broilers per pen from d one to 40. A Zn treatment x corn particle size interaction was observed for ending bird weight (EBW; P < 0.05) demonstrating that feeding small particle corn produced larger broilers except when supplemental Zn was not included. Broilers fed small particle corn or diets supplemented with Zn consumed the most feed (P < 0.05); however, FCR was decreased (P < 0.05) by 1.9 points for broilers fed large particle corn diets. Tibia Zn concentration was higher (P < 0.0001) for Zn supplemented diets, but no other treatment effects were observed. In conclusion, Zn supplement source had little effect on broiler performance; however, Zn supplementation per se optimized performance.     

Evaluation of increased fiber,decreased amino acids,or decreased electrolyte balance as dietary approaches to slow finishing pig growth rates

In swine production, pig movement restrictions or packing plant closures may create the need to slow growth rates of finishing pigs to ensure they remain at a marketable body weight when packing plant access is restored. Although dietary formulations can be successful at slowing pig growth, precision is needed regarding how to best formulate diets to achieve growth rate reductions. Thus, the objective was to evaluate three dietary experimental approaches aimed at slowing growth rates in finishing pigs. These approaches consisted of either increasing neutral detergent fiber (NDF), reducing essential amino acids, or reducing the dietary electrolyte balance through the addition of acidogenic salts. A total of 94 mixed-sex pigs (72.4 ± 11.2 kg BW) across two replicates were individually penned and assigned to 1 of 8 dietary treatments (n = 11–12 pigs/treatment): 1) Control diet representative of a typical corn–soybean meal-based finisher diet (CON); 2) diet containing 15% NDF from soybean hulls (15% NDF); 3) diet containing 20% NDF from soybean hulls (20% NDF); 4) diet containing 25% NDF from soybean hulls (25% NDF); 5) diet formulated as per CON but with 50% of the soybean meal replaced with corn (89% Corn); 6) diet containing 97% corn and no soybean meal or synthetic amino acids (97% Corn); 7) diet containing 2% anhydrous calcium chloride (2% CaCl₂); and 8) diet containing 4% anhydrous calcium chloride (4% CaCl₂). Over 28 d, pig body weights and performance were recorded weekly. At d 28, all pigs were ultrasound scanned and switched to the CON diet to evaluate compensatory gain from d 28 to 35. Overall, increased NDF did not impact any growth performance parameter (P > 0.05). Amino acid restriction reduced average daily gain (ADG), average daily feed intake (ADFI), and gain:feed (G:F) linearly (linear P < 0.001). Similarly, ADG, ADFI, and G:F were linearly reduced with increased CaCl₂ inclusion (linear P < 0.001). ADG differed during the compensatory gain period (P < 0.001), with 4% CaCl₂-fed pigs having a 47% increase in ADG compared with CON-fed pigs. Conversely, 15% and 25% NDF-fed pigs had reduced ADG compared with CON-fed pigs during the compensatory gain period. Gain efficiency differed from day 28 to 35 (P < 0.001), with 4% CaCl₂-fed pigs having a 36% increase in G:F compared with CON-fed pigs. Altogether, these data demonstrate that both amino acid restriction and CaCl₂ inclusion are effective at slowing pig growth, albeit at greater inclusion rates.     

The influence of phytase,pre-pellet cracked maize and dietary crude protein level on broiler performance via response surface methodology

Background: The reduction of crude protein levels in diets for broiler chickens may generate economic,environmental and flock welfare and health benefits; however, performance is usually compromised. Whole grain feeding and phytase may improve the utilization of reduced crude protein diets.Results: The effects of pre-pellet cracked maize(0, 15% and 30%) and phytase(0, 750 and 1500 FTU/kg) in isoenergetic maize-soy diets with three levels of crude protein(22%, 19.5% and 17%) were evaluated via a BoxBehnken response surface design. Each of 13 dietary treatments were offered to 6 replicate cages(6 birds/cage) of male Ross 308 broiler chicks from 7 to 28 d post-hatch. Model prediction and response surface plots were generated from experimental data via polynomial regression in R and only significant coefficients were included and discussed in the predicted models. Weight gain, feed intake and FCR were all influenced by pre-pellet cracked maize, phytase and crude protein level, where crude protein level had the greatest influence. Consequently, the reduction from 22% to 17% dietary crude protein in non-supplemented diets reduced weight gain, feed intake,relative gizzard weight, relative gizzard content and relative pancreas weight but improved FCR. However, the inclusion of 30% cracked maize to 17% crude protein diets restored gizzard weight and 1500 FTU phytase inclusion to 17% crude protein diets increased relative gizzard contents and pancreas weights. Cracked maize and phytase inclusion in tandem to 17% crude protein diets increased weight gain, feed intake and FCR; however, this FCR was still more efficient than broilers offered the non-supplemented 22% crude protein diet. Broilers offered the prepellet cracked maize and phytase inclusions reduced AME in 22% crude protein diets but improved AME by 2.92 MJ(14.16 versus 11.24 MJ; P 0.001) in diets containing 17% crude protein. Ileal N digestibility was greater in broilers offered diets with 17% crude protein than those offered the 22% crude protein diet; irrespective of phytase and pre-pellet cracked maize.Conclusion: Pre-pellet cracked maize and phytase inclusions will improve the performance of broilers offered reduced crude protein diets.     

Response of meat chickens to different sources of arginine in low-protein diets

Arginine activity in broiler diets can be supplied by L-arginine (Arg), guanidinoacetic acid (GAA) and L-citrulline (Cit), all of which are commercially available. This study was conducted to assess the effects of Arg source and level on broiler performance, nutrient digestibility and carcass parameters. Day-old Ross 308 cockerels (n = 768) were assigned to one of eight dietary treatments using a completely randomized design: normal protein (NP), low protein deficient in Arg (LP) and LP with two levels of either Arg (0.238% and 0.476%), GAA (0.309% and 0.618%) or Cit (0.238 and 0.476%). The LP was 5 percentage points lower in protein level than the NP. Wheat, sorghum, soya bean meal, canola meal, and meat and bone meal-based diets were fed over three feeding phases to 6 replicate floor pens with 16 birds each. Compared to NP, birds fed LP had reduced feed intake (FI, p < 0.001), reduced body weight gain (BWG, p < 0.001) and increased feed conversion ratio (FCR, p < 0.001) from day 0 to day 35. Additions of Arg or Cit to the LP at both levels resulted in increased BWG and reduced FCR (p < 0.05). Birds fed LP with GAA added had lower FCR (p < 0.05) but not higher BWG (p > 0.05) compared with the LP observed from day 0 to day 35. Supplementation of Arg, Cit and the low level of GAA to LP resulted in increased carcass yield, bone length, diameter and ash (p < 0.05) but did not increase ileal energy or nitrogen digestibility (p > 0.05). The findings indicate that Cit is an efficacious source of Arg activity in Arg-deficient diets.     

Poultry litter ash as a replacement for dicalcium phosphate in broiler diets

An experiment was designed to evaluate the nutritional value of poultry litter ash (PLA) under commercial-type conditions. Diets were formulated to meet the nutrient requirements of the broiler utilizing PLA at combinations of 0, 25, 50, 75, or 100% in starter, grower, and finisher diets as a replacement for dicalcium phosphate (DP). No significant effects were observed on BW, feed consumption, FCR, or mortality when broilers were fed PLA to 100% replacement for DP to 41 d of age. Processing performance, as measured by carcass and meat yield, of broilers at 42 d of age was also unaffected (P > 0.05). The complete substitution of DP with PLA failed to compromise growth and processing performance in market age broilers and the PLA produced via the combustion of poultry litter can be used as a phosphorus source in poultry diets.