Total replacement of soybean meal with alternative plant-based ingredients and a combination of feed additives in broiler diets from 1 day of age during the whole growing period.

The capacity of combinations of feed enzymes, natural betaine and a probiotic, combined with alternative plant-based ingredients, to totally replace soybean meal (SBM) in a broiler diet was evaluated. Day-old Ross 308 males (2,574) were assigned to 9 treatments (13 pens/treatment, 22 birds/pen) in a completely randomized design. All diets were pelleted and fed ad libitum in 4 phases: starter, grower, finisher 1, finisher 2 (0-10, 10-21, 21-35, and 35-42 d of age, respectively). Treatments included: 1) control diet containing SBM (SBM control), supplemented with phytase (PhyG), at 2,000, 1,500, 1000 and 1,000 FTU/kg in each phase and xylanase (X) at 750 U/kg, [crude protein (CP): 23.5%, 22.0%, 20.2% and 19.3% in each phase]; 2) to 5), alternative (ALT), SBM-free diets, containing the same CP level as the control ("CP high"), supplemented with PhyG as in the control, protease (P, 800 U/kg) and in 2) xylanase (750 U/kg) (ALT+PhyG+P+X), 3) xylanase-ß-glucanase (XB, 1,200 U/kg and 152 U/kg) (Alt+PhyG+P+XB), 4) XB plus betaine (800 g/ton) (ALT+PhyG+P+XB+Bet), and 5) XB plus a probiotic [150,000 colony forming units (CFU)/g] (ALT+PhyG+P+XB+Prob); 6) to 9) as treatments 2) to 5) but with CP reduced by -2.0 to -1.5% points vs. control ('CP low'). Final (d 42) BW and overall (d 0-42) feed conversion ratio (FCR) of birds fed the SBM control exceeded breeder objectives (+3.8% and -1.9%, respectively). Overall FCR was reduced and d 42 BW increased in birds fed "low" vs. "high" CP (P < 0.01). Overall FCR and feed intake were not different in ALT+PhyG+XB+P+Bet and ALT+PhyG+XB+P+Prob vs. the control, whereas final BW was reduced (P < 0.05) in all ALT treatments but close to breeder objectives (98.3%) in ALT+PhyG+XB+P+Prob. Feed costs of this treatment were similar to the control. Total replacement of SBM with alternative plant-based ingredients in a CP-low diet supplemented with hydrolytic enzymes and probiotics can achieve growth performance outcomes close to commercial breeder objectives.

Evaluating a novel consensus bacterial 6-phytase variant on growth performance of broilers fed U.S. commercial diets deficient in nutrients and energy through 63 days of age.

An experiment was conducted to evaluate the efficacy of a novel consensus bacterial 6-phytase variant expressed in Trichoderma reesei (PhyG) in broilers fed corn-soybean meal-based diets with application of dose-specific full nutrient and energy matrix values. Ross 708, straight-run broilers (n = 2,016) were assigned to one of 7 dietary treatments, with 12 replicate pens/diet and 24 birds/pen. Diets were a nutrient adequate control (PC), nutrient reduced negative controls 1, 2, and 3 (NC1, NC2, and NC3) with reductions in available phosphorus (avP) by 0.15%, 0.18%, and 0.19%, calcium (Ca) by 0.17%, 0.20%, and 0.21%, dig amino acids (AA) by 0.02%-0.05%, sodium (Na) by 0.03%-0.05%, and metabolizable energy (ME) by 62.8, 68.8, and 69.5 kcal/kg, respectively. Other diets were the NC1, NC2, and NC3 respectively supplemented with 500 (PhyG500), 1,000 (PhyG1000), and 2,000 (PhyG2000) FTU/kg. Over the 63-day feeding period, decreasing nutrient specifications lowered body weights (P < 0.05) in broilers from 4,518 g in PC to 4,256 g and 4,191 g and increased body weight-corrected feed conversion ratio (FCR, P < 0.05) from 1.92 in PC to 2.06 and 2.08 in the NC2 and NC3, respectively. Compared with PC, PhyG maintained (P > 0.05) BW in broilers fed PhyG500 (4,474 g), PhyG1000 (4,417 g), and PhyG2000 (4,449 g). Moreover, PhyG at all dose-levels maintained (P > 0.05) overall FCR vs. PC. The NC1, NC2, and NC3 diets decreased (P < 0.05) tibia ash vs. PC, and each PhyG500, PhyG1000, and PhyG2000 completely restored tibia ash to the similar levels (P > 0.05) as the PC. Carcass yield was decreased (P < 0.05) by NC1 (80.63%), NC2 (80.51%), and NC3 (80.31%) vs. PC (81.96%) with complete alleviation by PhyG500 (82.11%), PhyG1000 (81.80%), and PhyG2000 (81.54%). In conclusion, the novel consensus phytase variant completely compensated for the reduction in dietary avP, Ca, dig AA, and ME at each dose-level and maintained growth performance, bone quality, carcass characteristics, and nutrient digestibility in a typical corn-soybean mean based diet fed to broilers through 63 days of age.

As any reduction in dietary nutrients can negatively impact broiler productivity mitigating these effects is imperative. Dietary reductions in minerals, amino acids, and energy can all result in decreased growth and performance. Previous studies have demonstrated that exogenous phytase added to poultry diets can mitigate decreased growth caused by diets deficient in minerals, amino acids, and energy. In this current study, the addition of dose-dependent digestible AA and ME matrix values in addition to a mineral (P and Ca) down-specification in novel consensus bacterial 6-phytase variant supplemented diets resulted in maintained growth performance, bone quality, carcass characteristics, and nutrient digestibility equivalent to those of a nutritionally adequate diet. This study demonstrated the extra-phosphoric efficacy of phytase, at on top of the phosphoric efficacy, in a typical corn-soybean meal based diet fed to broilers through 63 days of age. The results of this current study confirmed that it is possible to account for phytase contributions for increased AA and energy availability, in addition to P and Ca.

Modeling improvements in ileal digestible amino acids by a novel consensus bacterial 6-phytase variant in broilers.

Data from 13 datasets from 4 trials on the effect of a novel consensus bacterial 6-phytase variant (PhyG) on the apparent ileal digestibility (AID) of amino acids (AA) in broilers were used to model AID AA responses. The datasets were obtained from 3 trial locations (New Zealand, Australia and United States) and collectively incorporated variations in diet composition (feedstuff composition, phytate-P (PP) level, limestone solubility), feed form (mash or pellet), bird genetics (strain), and age at sampling (11-35 d of age). In total, 384 observations were analyzed. First, the relationships between AID of AA (as coefficients) and increasing phytase dose level from 0 to 4,000 FTU/kg were evaluated across all datasets using exponential curve fitting. Second, the percentage unit change in AID of AA at each phytase dose level from baseline (basal diet [BD] without phytase) was calculated separately for each dataset and the data then modeled together using exponential curve fitting. The model-predicted mean coefficient of AID of total AA in basal diets was 0.76 (range 0.56 [Cys] to 0.83 [Glu]), which was increased by PhyG to 0.80 and 0.81 at 2,000 and 4,000 FTU/kg, respectively. Exponential increases in the percentage unit improvement in AID of 18 individual and of total AA with increasing phytase dose level were evident (P < 0.05). Improvements (vs. BD) at 2,000 FTU/kg and 4,000 FTU/kg, respectively, were greatest for Cys (+9.2 and +11.0% units), Met (after deduction of synthetic Met, +8.4 and +9.0% units), and Thr (after deduction of synthetic Thr, +6.2 and +7.3% units). The data demonstrated consistent improvements in the AID of AA by the phytase. The modeling results generated from data gathered from birds sampled at different ages and from different dietary settings with correction of synthetic AA for Lys, Met, Thr, and Trp, enabled a more accurate prediction of the digestible AA contribution from the diet by this novel phytase. This will allow diet-specific AA matrix recommendations to be made in commercial feed formulations.

Evaluation of the responses of broiler chickens to varying concentrations of phytate phosphorus and phytase. â ¡. Grower phase (day 12-23 post hatching).

A randomized complete block design study used 768 male broiler chickens to investigate the effects of phytate P (PP) and a novel consensus bacterial phytase variant (PhyG) concentration on growth performance, bone mineralization, apparent ileal digestibility (AID), and total tract retention (TTR) of nutrients in broiler chickens. Treatments were arranged in a 1 + 3 × 5 factorial with a nutrient-adequate positive control diet (PC) with 2.8 g PP/kg, 3 nutrient-reduced negative control diets (NC: PC minus 88 kcal/kg ME, 0.8 g/kg dig. Lys, 2.0 g/kg available P, 2.0 g/kg Ca and 0.5 g/kg Na) with varying PP (g/kg) levels, mainly from rice bran, at 2.3 (NC1), 2.8 (NC2), or 3.3 (NC3) and 5 PhyG doses at 0, 500, 1,000, 2,000, or 4,000 FTU/kg. All treatments had 6 replicate cages with 8 birds/cage. A commercial starter diet was fed from d 0 to 12 and the experimental diets from d 12 to 23 post hatching. Birds fed the NC2 diet without phytase had lower (P < 0.01) BW, BW gain, and feed intake (FI) as compared with birds fed the PC with the same PP level. With increasing phytate, there was a decrease (P < 0.05) in BW, BW gain, and FI. Phytase increased (P < 0.01) BW and feed efficiency of broiler chickens. An interaction (P < 0.05) between PP and phytase concentrations was observed on the AID of Met, Cys, and Thr. Linear decrease (P < 0.01) in the AID and TTR of P and Ca with increasing PP concentrations were observed. Phytase supplementation increased (P ≤ 0.05) the AID of P, Ca, and all AA. The TTR of P, Ca, and Zn was linearly increased (P < 0.01) by 112, 123, and 46%, respectively, when birds fed NC diets with 0 and 4,000 FTU/kg were compared. In conclusion, phytate reduced the growth performance and nutrient utilization of broiler chickens from d 12 to 23 post hatching while phytase ameliorated these negative effects.

Effect of increasing dose level of a novel consensus bacterial 6-phytase variant on phytate degradation in broilers fed diets containing varied phytate levels.

1. The effect of increasing the dose level of a novel consensus bacterial 6-phytase variant on apparent ileal digestibility (AID) of phosphorus (P), phytic acid (inositol hexa-phosphate, IP6) and ileal IP6 degradation profile was studied in diets containing varying phytate-P (PP) levels.2. Ross 308, one-day-old males (n = 1,800) were allocated to cages (20 birds/cage, six cages/treatment) in a completely randomised design employing a 3 × 5 factorial arrangement (three PP levels: 2.45 (low) 2.95 (medium) and 3.45 g/kg (high); five dose levels of phytase (PhyG): 0, 500, 1,000, 2,000 and 4,000 FTU/kg). Phased diets were based on wheat, corn, soybean meal, rapeseed meal and rice bran (d 0 to 10; 2.60 g/kg digestible P, 7.6 g/kg calcium (Ca); d 11 to 21; 2.10 g/kg digestible P, 6.4 g/kg Ca). Ileal digesta was collected on d 21 for determination of P, IP6 and IP-esters content. Data were analysed by factorial ANOVA; means separation was achieved using Tukey's HSD test.3. Increasing PP reduced AID of IP6 and sum of IP3-6 (%) (P < 0.05) but absolute P-release (g/kg diet) above NC was increased (P < 0.05) at high vs. low PP. Increasing phytase dose exponentially increased (P < 0.001) AID IP6, sum of IP3-6 (%) and digestible IP3-6-P g/kg diet (P < 0.001). AID P was increased but there was an interaction with PP level (P < 0.001). Ileal accumulation of IP5-3-P was universally low with PhyG at ≥1,000 FTU/kg (<0.06 g/100 g DM). At 2,000 and 4,000 FTU/kg, AID IP6 was 97.2, 92.7, 92.6% and 100, 97.2, 97.1%, respectively, at low, medium and high PP. At 2,000 FTU/kg, phytate-P release estimated as the increase (above NC) in ileal digestible sum of IP3-6-P in the diet was 2.26, 2.59 and 3.10 g/kg in low, medium and high PP, respectively.4. The data demonstrated that the novel phytase was effective in breaking down phytate to low IP-esters in diets with varied PP content but the optimal dose level for maximising P-release may differ in diets with varying PP content.

Evaluation of the responses of broiler chickens to varying concentrations of phytate phosphorus and phytase. â . Starter phase (day 1-11 post hatching).

Growth performance, tibia ash, apparent ileal digestibility (AID), and total tract retention (TTR) of nutrients responses of broiler chickens fed diets containing varying concentrations of phytate P (PP) and a novel consensus bacterial 6-phytase variant (PhyG) from d 1 to 11 post hatching were evaluated with 1,152 broiler chicks. Diets were a nutrient-adequate positive control diet (PC) with 2.8 g PP/kg or one of 15 nutrient-reduced negative control (NC: PC minus 88 kcal/kg ME, 0.8 g/kg dig. Lys, 2.0 g/kg available P, 1.8 g/kg Ca and 0.5 g/kg Na) diets with 3 PP (g/kg) levels, mainly from rice bran, at 2.3 (NC1), 2.8 (NC2), or 3.3 (NC3) and 5 PhyG supplementation at 0, 500, 1,000, 2,000, or 4,000 FTU/kg in a 1 + 3 × 5 factorial. All treatments had 6 replicate cages with 12 birds per cage. Despite comparable PP levels, birds fed the PC diet had greater (P ≤ 0.01) body weight (BW), feed intake (FI), tibia ash, AID of energy, AA, P, and Ca as compared with birds fed the NC2 without phytase. There was no interaction between PP and phytase for all responses. Increasing PP concentrations linearly decreased (P < 0.01) BW, FI, AID, and TTR of P and Ca. With phytase supplementation, there was a quadratic response (P < 0.05) in BW, FI, tibia ash, and a linear increase (P < 0.05) in the AID of energy, nitrogen, and all the measured AA. Increasing phytase dose from 0 to 4,000 FTU/kg increased (P < 0.01) AID of P and Ca by 88 and 18%, respectively. There was also a quadratic response (P ≤ 0.05) on TTR of P and Ca with increasing phytase dose. In conclusion, increasing levels of PP reduced growth performance and most nutrient utilization responses of broiler chickens while phytase supplementation positively impacted the responses of broiler chickens during d 1 to 11 post hatching.

Effect of a novel consensus bacterial 6-phytase variant in grower pigs fed corn-soybean meal-based diets formulated with a full nutrient matrix and no added inorganic phosphorus.

The capacity of a novel consensus bacterial 6-phytase variant (PhyG) to entirely replace dietary inorganic phosphorus (Pi) source in grower pigs fed diets with reduction of calcium (Ca), net energy (NE), and digestible amino acids (AA) was evaluated, using growth performance and apparent total tract digestibility (ATTD) of nutrients as outcome measures. A total of 352 mixed-sex pigs (initial BW 23.4 kg) were randomized to 4 treatments, 8 pigs/pen, and 11 pens/treatment. Diets were corn-soybean meal-based and formulated by phase (grower 1, 25 to 50 and grower 2, 50 to 75 kg BW). The positive control diet (PC) provided adequate nutrients and a negative control diet (NC) was formulated without Pi (1.2 g/kg ATTD P) and reduced in Ca (-0.12 to -0.13 percentage points), NE (-32 kcal/kg), and digestible essential AA (-0.004 to -0.026 percentage points) vs. PC. Two further treatments comprised the NC plus 500 or 1,000 FTU/kg of PhyG. Data were analyzed by ANOVA, mean contrasts and orthogonal polynomial regression. Nutrient reductions in the NC reduced (P < 0.05) average daily gain (ADG) during grower 1 and overall (73 to 136 d of age), increased (P < 0.05) feed conversion ratio (FCR) during grower 1 and overall and tended to reduce (P < 0.1) average daily feed intake (ADFI) during grower 2 and overall, vs. PC. Phytase supplementation improved (P < 0.05) FCR during grower 1, ADG during grower 2 and overall, ATTD of DM and P, and tended to improve DE (P = 0.053) in a linear dose-dependent manner. PhyG at 1,000 FTU/kg resulted in growth performance (all measures, all phases) equivalent to PC. The findings demonstrate that PhyG at 1,000 FTU/kg totally replaced Pi in complex grower pig diets containing industrial co-products, compensated a full nutrient matrix reduction and maintained performance.

A novel consensus bacterial 6-phytase variant completely replaced inorganic phosphate in broiler diets, maintaining growth performance and bone quality: data from two independent trials.

Total replacement of dietary inorganic phosphate (Pi) by a novel consensus bacterial 6-phytase variant (PhyG) in phytate-rich diets (>0.3% phytate-P) was investigated in 2 trials using growth performance and bone quality as outcome measures. Both trials utilized a completely randomized design with 5 dietary treatments across 4 phases: starter (0-10 d), grower (10-21 d), finisher 1 (21-35 d), and finisher 2 (35-42 d). Treatments comprised a nutritionally adequate positive control (PC) diet containing monocalcium phosphate and 4 experimental diets (IPF1, IPF2, IPF3, and IPF4), all containing no added Pi and reduced in Ca by 0.2 to 0.3% units vs. PC. IPF1contained PhyG at 1,000 FTU/kg (all phases); IPF2 contained PhyG at 1,000 FTU/kg (all phases) and was additionally reduced in digestible AA, ME, and sodium (-0.2 to -0.4% points, -74 kcal/kg, -0.04% points, respectively, vs. PC); IPF3 contained PhyG at 3,000 FTU/kg in starter, 2,000 FTU/kg in grower, and 1,000 FTU/kg in finisher phases; and IPF4 contained xylanase (2,000 U/kg) and PhyG (2,000 FTU/kg in starter, 1,500 FTU/kg in grower, and 1,000 FTU/kg in finisher phases) and was additionally reduced in ME (-71 kcal/kg vs. PC). Ross 308 broilers were used (trial 1: n = 1,200 mixed sex; 24 birds per pen × 10 replicates; trial 2: n = 1,300 males; 26 birds × 10 replicates). During all phases in both trials, all IPF treatments maintained or improved BW, ADG, ADFI, FCR and BW-corrected FCRc and bone quality parameters vs. PC. vs. PC, treatment IPF3 increased ADG during starter phase (+10.8%) and reduced overall FCRc (-12 points, P < 0.05) in Trial 1, and increased overall ADG (+4.4%), day 35 and day 42 BW (+3.5%, +4.9%), and reduced overall FCRc (-11 points) in Trial 2 (P < 0.05). IPF4 produced equivalent performance to IPF3 (both trials). These are the first data to demonstrate total replacement of Pi by microbial phytase during an entire growth cycle in broiler diets.

Effects of dietary calcium and available phosphorus levels and phytase supplementation on performance, bone mineral density, and serum biochemical bone markers in aged white egg-laying hens.

Exogenous phytase supplementation increases P and Ca availability to allow for the dietary reductions without negative consequences on productivity or skeletal health. Effects of a Buttiauxella sp. phytase (BSP) supplemented in available P (avP)-reduced and Ca-reduced diets on performance, BW, eggshell quality, serum biochemical bone markers, and bone densitometry were evaluated in egg-laying hens from 68 to 78 wk of age. One hundred hens were fed 1 of 5 diets (n = 20/treatment), including a positive control (PC) with 0.35% avP and 3.5% Ca, and the PC moderately reduced in avP and Ca levels by 0.187 and 0.159% of the diet (by 53 and 4.5%), respectively, (NC1) or severely reduced by 0.231 and 0.275% of the diet (by 66 and 7.9%), respectively, (NC2). Other diets were the NC1 or NC2 supplemented with BSP at 600 FTU/kg (NC1 + BSP or NC2 + BSP, respectively). Egg production and feed conversion ratio were maintained by NC1 but were 11.9% lower and 12.3% higher, respectively, with the NC2 than the PC, which was alleviated by supplemental BSP. Diet effects on FI and eggshell quality followed a similar pattern. Body weight was 2.9% lower for NC1, and 6.1% for NC2 than the PC; BSP alleviated the decreased BW. Serum pyridinoline (bone resorption marker) was 20 to 27% higher in NC2 hens than in the other groups, with no effects on other bone markers. Total and trabecular space bone mineral density in the proximal metaphysis were 8.4 and 15.2% lower for NC1, respectively, and 12.1 and 26.7% lower for NC2, respectively, than PC. Supplemental BSP completely alleviated the decreased bone densitometry measures in NC1, but only partially in NC2. The NC1 hens maintained performance but had decreased BW and bone quality; phytase supplementation restored productivity, BW, and bone quality. The Ca and avP deficiencies in the NC2 hens relative to other groups were partially alleviated by the 600 FTU/kg BSP.

The efficacy of 2 phytases on inositol phosphate degradation in different segments of the gastrointestinal tract, calcium and phosphorus digestibility, and bone quality of broilers.

The anti-nutritional effects of dietary inositol phosphates (IP6 through IP3) have been recognized in broiler chickens; however, inositol hexaphosphate (IP6) is more potent than the lower IP esters. The efficacies of 2 commercial phytases, a Buttiauxella sp. phytase (BSP) and a Citrobacter braakii phytase (CBP) at 500 and 1,000 FTU/kg, were studied on IP6-3 concentrations in the crop, proventriculus + gizzard, and distal ileum digesta, and ileal IP6 disappearance in broilers at day 22. Apparent ileal P and Ca digestibility, and bone quality at days 22 and 33 were also measured. Female Ross 308 broilers (n = 1,890; 30 birds × 7 diets × 9 replicates) were fed corn-soy-based crumbled diets. The 7 diets included a primary breeder recommendation-based positive control diet (PC); the PC marginally reduced in available P by 0.146% and Ca by 0.134% of the diet, (NC1) or moderately reduced by 0.174 and 0.159% of the diet, respectively (NC2). Other diets were the NC1 + BSP or CBP at 500 FTU/kg (NC1+500BSP and NC1+500CBP) and the NC2 + BSP or CBP at 1,000 FTU/kg (NC2+1,000BSP and NC2+1,000CBP). Each of the NC1 and NC2 had distal ileum IP6 disappearance similar to that of PC, but each had lower P digestibility and the majority of measured bone quality parameters than the PC. The ileal IP6 levels were decreased by 52.0 and 32.7% for NC1+500BSP and NC1+500CBP, respectively, relative to NC1 and by 73.6 and 50.9% for NC2+1,000BSP and NC2+1,000CBP, respectively, relative to NC2 (P < 0.001), with a similar effect for distal ileum IP6 disappearance. Overall, phytase in the NC diets increased P digestibility, and femur breaking strength and cortical bone mineral density at days 22 and 33. Overall, each of the phytases at each dose degraded IP6-3 across the gastrointestinal tract segments to increase P digestibility and the P and Ca utilization in bone. However, dietary BSP at 1,000 FTU/kg was most effective. Supplemental phytase degrades phytate to decrease the anti-nutritional effects in a dose- and phytase-dependent manner.

Effects of a combination of xylanase, amylase and protease, and probiotics on major nutrients including amino acids and non-starch polysaccharides utilization in broilers fed different level of fibers.

This study evaluated the effects of a combination of xylanase, amylase, and protease (XAP), with probiotics (3 Bacillus spp.) supplementation on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients in Cobb 500 broilers from 0 to 21 d. A completely randomized 2 × 4 factorial design (2 levels of fiber; 4 types of supplements) with 8 replicate cages (6 birds/cage) was used. Each low and high-fiber diet contained 500 FTU/kg Buttiauxella sp. phytase and was supplemented with: (a) none (control), (b) XAP (2,000 U xylanase + 200 U amylase + 4,000 U protease/kg diet), (c) probiotics (75,000 CFU/g of Bacillus spp.), or (d) XAP + probiotics. High fiber decreased (P < 0.05) nitrogen-corrected apparent metabolizable energy (AMEn), AID of all amino acids (AA), AID and ATTD of dry matter (DM), crude protein (CP), starch, and gross energy (GE). High fiber increased (P < 0.01) the flow of total non-starch polysaccharides (NSP) in both ileum and total tract. The XAP + probiotics increased (P < 0.01) AMEn as well as AID and ATTD of DM, CP, GE, starch, while alone, XAP yielded similar improvement except for DM compared with control. The supplemental XAP alone improved (P < 0.01) the digestibility of most of the AAs compared with control. Moreover, XAP + probiotics increased (P < 0.05) AID of all AA except arginine and serine compared with control. A fiber × supplements interaction (P < 0.05) was found for AID of histidine and threonine, and their digestibility in high-fiber diet was improved to a level comparable to low-fiber diet by XAP + probiotics. The flow of NSP in XAP group was 5 to 6% lower than in control while NSP flow in XAP + probiotic group was further 4% lower than that of XAP group (P < 0.01). The results infer that the combination of XAP and probiotics can effectively optimize the nutrient digestibility in broilers fed both low and high-fiber diets.

The ranked importance of dietary factors influencing the performance of broiler chickens offered phytase-supplemented diets by the Plackett-Burman screening design.

1.The objective of the present study was to rank the importance of the following dietary factors; canola meal, wheat, whole barley, digestible lysine, phytate-P, calcium, available P, sodium and three NSP-degrading feed enzymes. Their influence on growth performance, gastro-intestinal tract parameters, energy utilisation, ileal N digestibility and disappearance rates were determined via the Plackett-Burman design in broiler chickens offered phytase-supplemented diets. 2. The eleven dietary factors were assigned two levels in the Plackett-Burman design matrix. The resulting twelve dietary treatments were offered to six replicates per treatment (six birds per cage) with a total of 468 male Ross 308 broiler chicks from 7 to 28 d post-hatch. 3. Increasing digestible lysine levels improved weight gain by 15.6% (P < 0.001) and gain:feed by 9.36% (P < 0.001). Increasing calcium levels reduced weight gain by 6.36% (P < 0.001) and gain:feed by 2.60% (P < 0.001). The high calcium level increased gizzard pH from 2.78 to 3.01 (P < 0.005). Whole barley significantly increased relative gizzard weights and contents, pancreas weights and both ileal N digestibility coefficients (0.774 versus 0.803; P < 0.001) and ileal N disappearance rates (23. 3 versus 24.5 g/bird/day; P < 0.001). 4. Overall, digestible lysine level and calcium level were identified as the most influential dietary factors to influence growth performance of broilers offered phytase-supplemented diets, which hold implications for practical diet formulations.

Effects of direct-fed microorganisms and enzyme blend co-administration on intestinal bacteria in broilers fed diets with or without antibiotics.

Direct-fed microorganisms (DFM) and exogenous enzymes have been demonstrated to improve growth performance in poultry and are potentially important alternatives to antibiotic growth promoters (AGP). We investigated the administration of a feed additive composed of a DFM product containing spores of 3 Bacillus amyloliquefaciens strains and an enzyme blend of endo-xylanase, α-amylase, and serine-protease in diets with or without sub-therapeutic antibiotics in broiler chickens over a 42-d growth period. Evaluation of growth performance determined feed efficiency of broiler chickens which were administered the feed additive was comparable to those fed a diet containing AGPs. Characterization of the gastrointestinal microbiota using culture-dependent methods determined administration of the feed additive increased counts of total Lactic Acid Bacteria (LAB) relative to a negative control and reduced Clostridium perfringens to levels similar to antibiotic administration. Additionally, greater counts of total LAB were observed to be significantly associated with reduced feed conversion ratio, whereas greater counts of C. perfringens were observed to be significantly associated with increased feed conversion ratio. Our results suggest the co-administration of DFMs and exogenous enzymes may be an important component of antibiotic free poultry production programs and LAB and C. perfringens may be important targets in the development of alternatives to AGPs in poultry production.

The addition of a Buttiauxella sp. phytase to lactating sow diets deficient in phosphorus and calcium reduces weight loss and improves nutrient digestibility.

Improving the efficiency of P use by pigs is especially important for lactating sows, whose metabolic requirements for P and Ca are high. The effect of a sp. phytase on lactating sow performance and nutrient digestibility was investigated using the combined data set for 6 studies. Treatments included a nutritionally adequate positive control diet (PC), a negative control diet (NC; with an average reduction of 0.16% available phosphorous and 0.15% Ca vs. PC), and NC supplemented with a sp. phytase at 250, 500, 1,000 or 2,000 phytase unit (FTU)/kg, respectively. Phosphorus and Ca deficiency in the NC resulted in significantly higher BW loss compared with the PC. All phytase treatments maintained BW loss at the same level as the PC. Increasing doses of phytase significantly ( < 0.05) reduced sow BW loss and increased energy intake, with improvements most apparent in sows older than parity 5. The positive effects on BW and energy intake were not observed in first-parity sows. This may be a consequence of fewer first parity sows in the data set. The apparent total tract digestibility of DM, OM, and CP were not affected by phytase supplementation. Digestible P and Ca were significantly improved (linear, < 0.0001; quadratic, < 0.0001) by increasing the dose of phytase supplementation. Significantly lower apparent total tract digestibility of energy, Ca, and P was found in the NC treatment vs. the PC treatment, whereas no significant differences were found between phytase treatment and the PC treatment. In conclusion, phytase supplementation at a level of 250 FTU/kg can replace 0.16% available phosphorous and 0.15% Ca; however, increasing the phytase dose can further reduce BW loss in sows fed P- and Ca- deficient diets.

Utilization of stereoisomers from alpha-tocopherol in livestock animals.

Alpha-tocopherol derived from natural source is a single stereoisomer (i.e. RRR-alpha-tocopherol), whereas synthetic alpha-tocopherol consists of a mixture of eight stereoisomers, including RRR-, RRS-, RSR-, RSS-alpha-tocopherol (the 2R isomers, R configuration at positions 2' of the phytyl tail) and SRR-, SSR-, SRS- and SSS-alpha-tocopherol (the 2S isomers, S configuration at positions 2' of the phytyl tail). R and S are assigned by the sequence-rule procedure, i.e. the priorities of the substituents decrease in clockwise direction or anti-clockwise direction at each chiral centre. Not all these stereoisomers are equally bio-available, which can be explained by the differences in the rate of degradation, transportation and retention. Humans and livestock animals can only utilize the 2R forms, while the 2S forms have very low bio-availability or basically are not bio-available. The utilization of 2R forms differs between different animal species. For humans and livestock animals, RRR-alpha-tocopherol has the highest bio-availability compared with other stereoisomers, while other 2R forms have lower bio-availability compared with RRR-alpha-tocopherol. The relative bio-availability of RRR- and all-rac-alpha-tocopherol is related to animal species, ages of animals and assessment criteria. In general, recent literature studies have demonstrated that the relative bioavailability of RRR- and all-rac-alpha-tocopherol is 2:1, differing from the commonly used conversion factor of 1.36:1. The latter was based on rat-resorption-gestation test. Most recent studies have shown that this conversion factor of 1.36:1 is not applicable to livestock animals and based on other metabolic functions. When IU is required to express vitamin E activity, new conversion factors need to be defined for livestock animals. Quantitative determination of bio-availability of the individual alpha-tocopherol stereoisomers will give a more detailed picture of the bioavailability of natural and synthetic vitamin E forms.

Bio-discrimination of alpha-tocopherol stereoisomers in rearing and veal calves fed milk replacer supplemented with all-rac-alpha-tocopheryl acetate.

This study evaluated the biological discrimination of different alpha-tocopherol stereoisomers (i. e. RRR-, RRS-, RSR-, RSS- and the four 2S-alpha-tocopherols) from all-rac-alpha-tocopheryl acetate supplementation in milk replacer for rearing and veal calves respectively, in practical farming conditions. Two experiments were conducted. In experiment 1, six rearing calves were fed milk replacer supplemented with 80 mg/kg all-rac-alpha-tocopheryl acetate for a period of 9 weeks. The calves were supplied calf starter concentrate from 1 to 12 weeks. In experiment 2, six veal calves were fed milk replacer supplemented with 80 mg/kg all-rac-alpha-tocopheryl acetate for a period of 24 weeks. Blood samples were taken at the start and every 4 weeks until 12 weeks for rearing calves in experiment 1, and until slaughter (24 weeks) for veal calves in experiment 2. Liver, adipose, muscle, and brain samples were taken at slaughter of the six veal calves in experiment 2. The distribution of different alpha-tocopherol stereoisomers in feed, plasma, and tissues was analyzed. In both experiments, it was observed that RRR-alpha-tocopherol was the dominant stereoisomer in plasma and tissues. The average percentage of the RRR-alpha-tocopherol stereoisomer was 64 %, and 39 % of the total alpha-tocopherol in plasma for rearing and veal calves, respectively. The higher RRR-alpha-tocopherol stereoisomer proportion as percentage of the total alpha-tocopherol in rearing calves was related to higher dietary natural vitamin E intake. Other 2R-alpha-tocopherol stereoisomers had lower utilization efficiency than RRR-alpha-tocopherol stereoisomer. 2S-alpha-tocopherol stereoisomers were basically not utilized by calves.

Changes in oxygen content and acid-base balance in arterial and portal blood in response to the dietary electrolyte balance in pigs during a 9-h period after a meal.

The effect of two dietary electrolyte balance (dEB, Na+ + K+ - Cl-) levels on arterial and portal blood oxygen content, blood pH, and acid-base status in pigs was studied during a 9-h period after a meal, using a crossover experimental design. The dEB levels were established by changing the Cl- level in the diets. Four pigs with a mean weight of 45 kg were surgically fitted with catheters in the carotid artery and portal vein. Two dEB levels (-100 and 200 mEq/kg) were evaluated in two periods of 1 wk each. Feed was given at 2.6 times the maintenance requirement for energy in two meals per day. Water was freely available. Blood samples were taken at 0, 0.5, 1, 1.5, 2, 3, 4, 6, and 9 h after feeding. Blood hemoglobin; O2 pressure; O2 saturation; O2 content; pH; PCO2; HCO3-; base excess; and Na+, K+, and Cl- contents were measured. Oxygen contents in arterial and portal blood were lower (P < 0.008) in the -100 mEq/kg group (5.78 and 4.82 mmol/L respectively) compared to the 200 mEq/kg group (6.18 and 4.99 mmol/L respectively). This was related to the lower hemoglobin content in the blood of animals in the -100 mEq/kg group. Arterial and portal blood pH were lower (P < 0.003) at -100 mEq/kg (7.46 and 7.37) than at 200 mEq/kg (7.49 and 7.43). The difference in blood pH between the two groups was sustained throughout the sampling period. The average values of arterial and portal blood for base excess and HCO3- content were higher (P < 0.001) at high dEB (6.96 and 31.0 mmol/L, respectively, for -100 mEq/kg and 12.54 and 35.9 mmol/ L, respectively, for 200 mEq/kg). The Na+ concentration in the blood was increased and K+ and Cl- concentrations were decreased (P < 0.02) by increasing dEB from -100 mEq/kg to 200 mEq/kg. Blood electrolyte balance level was higher (P < 0.001) in the 200 mEq/kg dEB group than in the -100 mEq/kg dEB group. In conclusion, dEB changed blood oxygen content and pH, and influenced the acid-base buffer system in pigs. Also, within each group, pigs maintained a relatively constant blood pH level during the 9-h period after feeding.

Feed intake, growth, digestibility of dry matter and nitrogen in young pigs as affected by dietary cation-anion difference and supplementation of xylanase.

An experiment was conducted to test the effect of dietary cation-anion difference (CAD, Na(+) + K(+)-Cl(-), mEq/kg diet) and xylanase addition on feed consumption, digestibility of nutrients, plasma electrolyte balance and growth performance in young pigs. A 2 x 3 factorial arrangement with three dietary CAD levels (-100, 200, and 500 mEq/kg) and two levels of xylanase supplementation (0 and 0.1% xylanase derived from Trichoderma longibrachiatum) was used. Thirty-six individually housed, castrated pigs (5 weeks old) with an initial body weight of 9.34 +/- 0.28 kg (mean +/- SEM) were randomly assigned to the six treatments. Diets were provided to pigs as cold pellets. Pigs had ad libitum access to feed and water. Venous plasma Cl(-) concentration was higher (p < 0.0001) in dietary CAD of - 100 mEq/kg group compared with the other two CAD groups. Dietary CAD did not affect Na(+) and K(+) concentrations in the venous plasma. Growth rates were higher (p < 0.05) in pigs receiving dietary CAD of 200 mEq/kg (657 g/pig.day) and dietary CAD of 500 mEq/kg (603 g/pig.day) than in pigs receiving dietary CAD of -100 mEq/kg (484 g/pig.day). Faecal dry matter and nitrogen decreased with increasing dietary CAD. Faecal apparent digestibility of dry matter and nitrogen was higher (p < 0.05) in the dietary CAD of 500 mEq/kg compared to the two lower level CAD groups. Supplementation of xylanase did not affect the performance of pigs. Xylanase addition in the diet significantly increased apparent faecal digestibility of dry matter and tended to increase apparent digestibility of nitrogen. No interaction between dietary CAD and xylanase was found. In conclusion, dietary CAD influenced the performance and digestibility of nutrients of pigs. Xylanase supplementation improved digestibility of dry matter.

Performance, digesta characteristics, nutrient flux, plasma composition, and organ weight in pigs as affected by dietary cation anion difference and nonstarch polysaccharide.

Two dietary cation anion difference (CAD) levels (-100 and 200 mEq/kg) and two dietary nonstarch polysaccharide (NSP) levels (10 and 15%) were used in a 2 x 2 factorial arrangement in two randomized blocks (trials) to evaluate performance, digesta pH and buffer capacity, apparent digestibility, plasma composition, and organ weight in pigs. Seven pigs with a mean initial weight of 7.5 kg were used in each treatment. Pigs had free access to feed and water during the 3-wk experimental period. At the end of the experiment, all pigs were killed approximately 2.5 h after addition of fresh feed. Liver, kidneys, and small and large intestine were removed and weighed immediately. Gastric and small intestinal (divided into two equal parts) digesta were collected. Dry matter, pH, buffering capacity, viscosity, acid insoluble ash, mineral content (Na+, K+, and Cl-), nitrogen, and gross energy content (only in the second part of the small intestine) of the digesta were measured. An interaction (P < 0.05) between dietary CAD and dietary NSP was observed for feed intake, growth, apparent digestibility of DM and gross energy in the distal small intestine, and chloride in the stomach and duodeno-jejunal part of the small intestine. Increasing dietary NSP content increased apparent digestibility of DM and chloride in the stomach and increased apparent digestibility of DM, chloride, sodium, and potassium in the first part of the small intestine. Lowering dietary CAD levels significantly increased apparent digestibility of DM in the first part of the small intestine and decreased chloride influx in the stomach and the small intestine. No significant differences were found for pH, buffering capacity, and viscosity of digesta, except the buffering capacity in the second part of the small intestine, which was higher (P < 0.05) in the 200 mEq/kg CAD group than in the -100 CAD mEq/ kg group. Plasma urea decreased in the low dietary CAD groups and plasma ammonia increased in the high NSP groups. Large intestine weight was significantly less for the -100 mEq/kg CAD groups than for the 200 mEq/kg CAD groups. In conclusion, the effect of CAD on feed intake and growth in pigs depends on dietary NSP levels.