The impact of age and feeding length on phytase efficacy during the starter phase of broiler chickens

Gene expression of calcium transporters Calbindin-D28K and TRPV6 in Japanese quails (Coturnix japonica) subjected to phytase super-dosing and under different temperatures

This study aimed to evaluate the effects of phytase super-dosing in the diet of laying quails subjected to different temperatures, their performance, blood biochemistry, and gene expression of the epithelial calcium transporters Calbindin-D28 K and TRPV6. Seven hundred and twenty (720) Japanese quails in the production phase were distributed in a completely randomized design, in a 5 × 3 factorial scheme, with five levels of phytase supplementation (0, 500, 1000, 1500 and 3000 FTU/kg) and three temperatures (24°C, 30°C and 36°C), totaling 15 treatments, and six replicates of eight birds each. The study began at 8 weeks of age and continued for two 21-day cycles, totaling 42 days of experiment. Performance parameters, serum biochemistry, and gene expression of calbindin-D28 K and TRPV6 were measured through real-time PCR. The data were subjected to analysis of variance, Tukey, and regression. Birds kept at 36°C showed lower feed intake than those kept at 24°C and 30°C. At 30°C, birds had lower serum uric acid levels than birds at 36°C, and higher total egg production, egg mass, and Calbindin-D28 K gene expression in the uterus than those at 24°C and 36°C. Birds kept at 24°C had higher serum calcium and phosphorus levels than those kept at 30°C and 36°C. At a supplementation level of 1500 FTU, phytase provided greater eggshell thickness in quails kept at 36°C and greater calbindin-D28 K gene expression in the kidney. Therefore, the use of 1500 FTU of phytase is recommended for Japanese quail exposed to high temperatures, since phytase overdosage has been shown to be effective in mitigating the negative effects of heat stress.

Ileal phosphorus digestibility of soybean meal for broiler chickens remains consistent across institutions in a collaborative study regardless of non-phytate phosphorus concentration in the pre-experimental starter diet

The same experimental protocol was used in 4 institutions to evaluate the impact of non-phytate phosphorus (nPP) concentration in the starter diet on regression method-derived ileal P digestibility of soybean meal (SBM) during the subsequent grower phase. A total of 1,536 Ross 308 male broiler chickens on d 0 post hatching were allotted to 2 pre-experimental starter diets that contained 3.5 or 4.5 g nPP/kg (96 replicate cages per diet, 8 birds per cage) for 18 d. Subsequently, 576 birds from each starter diet were selected and allocated to 3 experimental semi-purified grower diets containing 400, 510, or 620 g SBM/kg (32 replicate cages per diet, 6 birds per cage) for 3 d until collection of ileal digesta. Statistical analysis was conducted as a randomized complete block design with the starter period as whole plot and the grower period as split-plot. The only significant 2-way interaction was between grower diet and experimental institution (P < 0.05) on BW gain and gain to feed ratio. The main effect of institution and grower diet impacted (P < 0.05) feed intake, the digestibility of DM, P, and calcium, and disappearance of inositol hexakisphosphate (InsP6) in the grower diets. Birds fed the 3.5 g nPP/kg starter diet had lower (P < 0.05) BW gain and feed intake during the grower period, but presented higher (P < 0.05) digestibility of P and disappearance of InsP6 compared with the birds that were fed the 4.5 g nPP/kg starter diet. Regression method-derived ileal P digestibility of SBM was determined to be 46 or 42% for the respective 3.5 or 4.5 g nPP/kg pre-experimental starter diet and was not affected by the nPP concentration or by the institution. In conclusion, the experimental protocol used in the current study resulted in similar estimates across multiple institutions and is thus endorsed for future application in studies that aim to expand the database of digestible P content in plant source feed ingredients.

Comparison of different protein sources on the phosphorus digestibility of soybean meal for broiler chickens determined using the regression method

A study was conducted to evaluate the P digestibility in soybean meal (SBM) using the regression method with different basal diet that varied in protein sources. The treatments were organized in a 4 × 3 factorial arrangement, where 4 semipurified diets were formulated with varying source of protein (no protein supplement, or added casein, potato protein isolate (PPI), or dried egg albumen (DEA) at 60 g/kg) and 3 dietary levels of SBM (290, 370, or 450 g/kg). The study was a randomized complete block design with 8 replicate cages of 6 birds per cage. The experimental diets were fed from d 19 to 22 posthatching, excreta samples were collected from d 20 to 22, and ileal digesta samples were collected on d 22. Data were analyzed as a 2-way ANOVA using the GLM procedure. The digestibility and total tract utilization of DM, P, Ca, and N were affected by protein source (P < 0.05). Diets with casein presented the highest (P < 0.05) digestibility of N. Increasing SBM level in all dietary protein sources reduced (P < 0.001) the digestibility and total tract utilization of DM. The regression-derived ileal digestibility of P in SBM was 57.8 (SE = 3.78), 63.2 (SE = 5.02), 58.8 (SE = 4.53), and 35.3% (SE = 5.27) for diets without protein supplement, with casein, PPI, or DEA, respectively; the corresponding P retention were 52.2 (SE = 11.09), 83.4 (SE = 14.89), 42.6 (SE = 15.88), and 51.9% (SE = 14.67). The protein source affected (P < 0.05) the slope and intercept of P digestibility in SBM. A comparison of the coefficients using confidence intervals demonstrated that the ileal digestibility of P in SBM determined in diets with DEA was lower (P < 0.05) than the other protein sources, which did not differ from one another. These results indicate that the selection of dietary protein supplements may affect P digestibility assays using the regression method.

Digestible calcium equivalency of phytase and nutrient utilization of broiler chickens fed graded levels of limestone or phytase during the starter phase

The current study aimed to quantify the digestible calcium (Ca) equivalency of a new phytase (HiPhorius) in broiler chickens. A total of 1,152 male Cobb 500 broiler chickens were used in an experiment in which 8 diets consisting of graded levels of Ca supplied with limestone or graded levels of the phytase were fed. The 8 dietary treatments were based on a corn-soybean meal diet containing 5.1 g/kg of Ca and 5.1 g/kg of phosphorus (P) as negative control (NC); the NC + 1.3, 2.6, or 3.9 g/kg of Ca from limestone; and the NC + 500, 1,000, 2,000, or 4,000 FYT/kg of phytase. Birds were fed the experimental diets for 3 d (from d 7 to 10) or 14 d (from d 7 to 21) to determine apparent ileal digestibility (AID) and apparent total tract retention (ATTR) of dry matter (DM), CP, Ca, and P. In the 10-day-old birds, increasing the levels of Ca decreased the AID of P and Ca (linear, P < 0.05). Increasing the levels of phytase quadratically improved (P < 0.05) the AID of Ca and P. The AID of DM and CP in the younger birds quadratically increased (P < 0.05) as the levels of Ca increased. There were linear and quadratic effects (P < 0.05) of increasing phytase level for the AID of DM and a linear effect (P < 0.05) for the AID of CP. In the 21-day-old birds, increasing Ca levels resulted in a linear decrease (P < 0.05) in the AID of CP and P, and a quadratic decrease (P < 0.05) in the ATTR of CP. Increasing phytase levels linearly and quadratically (P < 0.05) improved the AID and ATTR of CP, P, and the ATTR of Ca. The analyzed phytase activity in the diets supplemented with phytase ranged from 1,520 to 7,661 FYT/kg. The digestible Ca equivalence for dietary phytase at 1,520 to 7,661 FYT/kg ranged from 1.55 to 2.02 g/kg in the 10-day-old birds fed for 3 d and from 0.52 to 0.64 g/kg in 21-day-old birds fed for 14 d. The results showed the reduction in Ca level that could be accommodated by phytase supplementation, which is markedly different between the younger and older birds. Feeding duration influenced the impact of phytase supplementation on Ca and P digestibility, with better efficacy of phytase observed in the 10-day-old birds fed for 3 d. Also, the results showed the extra-phosphoric effects of phytase on the utilization of other essential nutrients such as protein and Ca.

Description of 3 failed attempts to estimate the calcium equivalency of phytase for growth performance and tibia ash of broiler chickens when using graded dietary levels of limestone

Three broiler experiments were conducted to estimate the Ca equivalency of a novel phytase using direct and indirect methods. All 3 experiments employed 4 concentrations of limestone to create 4 reference diets, deficient in nonphytate P, with increasing dietary Ca. Phytase was supplemented to the lowest Ca reference diet at 350, 700, 1,400, or 2,800 FYT/kg in experiment (Exp.) 1 and Exp. 2 and at 500, 1,000, 2,000, or 4,000 FYT/kg in Exp. 3. Broilers were fed from d 8 to 10 and 20 to 24, 19 to 21, or 7 to 10 and 7 to 21 posthatching in Exp. 1, 2, or 3, respectively. Diet did not affect growth performance or tibia ash in Exp. 1. Reducing the dietary Ca linearly (P < 0.05) increased body weight gain (BWG) and feed intake (FI) in Exp. 2 or Exp. 3. Feed conversion ratio (FCR) was decreased (linear or quadratic, P < 0.05) as dietary Ca was reduced in Exp. 2 or Exp. 3 (d 7-21). Tibia ash percent linearly (P < 0.05) decreased as dietary Ca decreased in Exp. 3 but only from d 7 to 21 and phytase increased (linear or quadratic, P < 0.05) FI and BWG, and decreased FCR. In Exp. 1 (d 8-10) and Exp. 2, apparent ileal digestibility (AID), total tract retention, and apparent digested and retained Ca or P increased (linear or quadratic, P < 0.05) as dietary Ca decreased. Phytase increased (linear or quadratic, P < 0.05) AID and apparent digested and retained Ca or P in Exp. 1 or Exp. 2. Due to the nature of the effect of dietary Ca on performance or tibia ash, it was not possible to use the indirect method to estimate the Ca equivalence of phytase in the current experiments. The total and digestible Ca equivalence of phytase could be estimated using the direct method. These experiments highlight challenges to consider when designing experiments to estimate the Ca equivalency for phytase in the future.

Ileal mineral digestibility and expression of nutrient transporter genes of broiler chickens in response to variable dietary total Ca and phytase supplementation are influenced by time on experimental diet and age of the birds

Two experiments were conducted to determine the impact of Ca, phytase, sampling time, and age on the digestibility (AID) of Ca and P and the expression of their transporters. Cobb 500 male chicks (N = 600) were used in each experiment and allocated to cages with 10 (Exp 1, 8-11 d) or 5 (Exp 2, 21-24 d) birds/cage and 10 (Exp 1) or 20 (Exp 2) reps/treatment. Treatments were a 2 × 3 factorial arrangement, with low (LOW) or standard (STD) Ca level and 3 phytase (PHY) levels (0, 300, or 3,000 FYT/kg). Ileal digesta were collected at 8, 12, 24, 48, and 72 h, and jejunum tissues at 12, 48, and 72 h after the start of feeding experimental diets. In Exp 1, there was no effect of Ca or phytase on the AID of Ca at 8, 12, or 24 h. Phytase increased the AID of P (P < 0.05) at all time points, and the magnitude was influenced by Ca. At 12 h, the mRNA level of P (NaPi-IIb) and Ca (CaSR) transporters was greatest in the LOW diets without phytase (Ca × PHY, P ≤ 0.06). In Exp 2, the STD diet decreased the AID of Ca and P (P < 0.05) at 8, 24, 48, or 72 h. Phytase increased the AID of Ca (P < 0.05) at 8, 12, and 24 h, and decreased the AID of Ca (quadratic, P < 0.05) in the STD diet (48 h). The AID of P (P < 0.05) increased with phytase at all sampling times. At 48 h, 3,000 FYT/kg decreased (P < 0.05) mRNA expression of NaPi-IIb and Ca transporter ATP2B1 in the STD diet (Ca × PHY, P < 0.05). In conclusion, to avoid adaptation of broilers to Ca and P deficiencies, the optimal time on experimental diets is ≤ 48 h for young broilers and ≤ 24 h in older birds due to up- or down-regulation of Ca and P transporters in response to dietary Ca, P, and phytase.

A study of solely used phytase or in combination with multi-carbohydrase on growth performance along with tibia mineralization, and carcass traits in broilers fed nutrient-deficient diets

The objective of this study aimed to investigate the effectiveness of phytase alone and in combination with multi-carbohydrase in available phosphorus (AP) and energy-deficient diets on growth performance, nutrient digestibility, tibia traits, and carcass quality of broilers. A total of 288 1-d-old Ross 308 broiler chicks were randomly assigned to one of 6 dietary treatments in a completely randomized design, with each treatment having 6 replicates and 8 birds per cage. The treatments were as follows: 1) positive control with adequate nutrition (PC); 2) 0.20% AP-deficient diet without phytase (NC-1); 3) 0.25% AP-deficient diet without phytase (NC-2); 4) NC-1 diet plus 500 FTU/kg phytase (NCP-1); 5) NC-2 diet plus 750 FTU/kg phytase (NCP-2); and 6) NC-2 with 100 kcal/kg ME deficient diet plus 1,000 FTU/kg phytase and multi-carbohydrase: 2,200 U/kg galactomannanase, 30,000 U/kg xylanase, 22,000 U/kg β-glucanase, and 700 U/kg α-galactosidase (NCPM). Broilers in the PC group and those fed enzyme-supplemented diets exhibited greater (P < 0.05) growth performance in terms of body weight, average daily gain, and feed conversion ratio, along with enhanced tibia mineralization through the ash, calcium (Ca), phosphorus (P) composition, and tibia breaking strength compared to NC diets throughout the study. Among the treatments, broilers assigned to the NCPM group showed greater (P < 0.05) levels of energy and P digestibility on days 21 and 35. Concerning carcass characteristics, the leg meat yield was greater (P < 0.05) in broilers fed the NCP-2 diet compared to all other treatments on days 21 and 35. Supplementation of phytase at doses of 500 FTU/kg and 750 FTU/kg effectively recovers AP deficiencies of 0.20% and 0.25%, respectively, in broiler diets without compromising the growth performance of broilers. Additionally, combining multi-carbohydrase and phytase led to AP and energy loss recovery, which improved tibia mineralization and nutrient digestibility through their synergistic interaction.

Efficacy of a bacterial 6-phytase supplemented beyond traditional dose levels on jejunal mucosa-associated microbiota, ileal nutrient digestibility, bone parameters, and intestinal health, and growth performance of nursery pigs

This study aimed to determine the efficacy of a bacterial 6-phytase (Buttiauxella spp.) supplemented beyond traditional dose levels based on jejunal mucosa-associated microbiota, apparent ileal digestibility (AID), intestinal health and bone parameters, and growth performance of nursery pigs. Seventy-two weaned pigs (36 barrows and 36 gilts at 21 d of age with 5.8 ± 0.5 kg BW) were allotted to six treatments based on randomized complete block design with sex and initial BW as blocks and fed in three dietary phases (phase 1 for 14 d, phase 2 for 10 d, and phase 3 for 14 d). The treatments included a negative control (NC) diet without phytase formulated meeting nutrient requirements by NRC and the other five treatments were deficient in calcium (Ca) and phosphorus (P) by 0.12% with increasing levels of a bacterial 6-phytase (0, 500, 1,000, 2,000, and 5,000 FTU/kg feed). Titanium dioxide (0.4%) was added to phase 3 diets as an indigestible marker to measure AID of nutrients. On day 45, all pigs were euthanized to collect ileal digesta to measure AID, the third metacarpus to measure bone parameters, and jejunal mucosa to evaluate intestinal health and microbiota. Data were analyzed using the MIXED procedure for polynomial contrasts and the NLMIXED procedure for broken line analysis using the SAS 9.4. Broken line analysis demonstrated that 948 FTU/kg feed increased (P < 0.05) the ADG and the bone P content. Increasing phytase supplementation increased (linear, P < 0.05) AID of CP, bone P, and ash content. Increasing phytase supplementation reduced (P < 0.05) the fecal score during phases 2 and 3. Broken line analysis demonstrated that 1,889 FTU/kg feed increased (P < 0.05) bone breaking strength. Increasing phytase supplementation (PC vs. Phy) increased (P < 0.05) AID of ether extract (EE) and P. The supplementation of phytase at 2,000 FTU/kg feed tended (P = 0.087) to reduce the relative abundance of Prevotellaceae. In conclusion, the supplementation of a bacterial 6-phytase beyond traditional dose levels improved bone breaking strength, bone ash, and P content, AID of CP, EE, and P, and growth performance of nursery pigs with reduced relative abundance of Bacteroidetes specifically Prevotellaceae in the jejunal mucosa. Supplementation of a bacterial 6-phytase between 1,000 and 2,000 FTU/kg feed provided benefits associated with growth performance and bone parameters of nursery pigs.

Phytase Supplementation of Four Non-Conventional Ingredients Instead of Corn Enhances Phosphorus Utilization in Yellow-Feathered Broilers

The present study was conducted to evaluate the effects of unconventional feedstuff such as wheat, broken rice, distillers dried grains with soluble (DDGS), and wheat bran, replacing 15% of the corn in the basal diet and the supplementation of bacterial phytase on nutrition digestibility. A total of 500 yellow-feathered broilers with similar body weights of 1.65 ± 0.15 kg were divided into 10 dietary treatments with 5 replicates per treatment (5 male and 5 females per cage). The AME and AIDE were significantly higher when supplied with phytase (p < 0.01) in the DDGS group. The ileal and total tract digestibility of calcium and phosphorus were significantly increased in the phytase-supplied group (p < 0.001). Additionally, the ileal digestibility of CP was increased when phytase was supplemented (p < 0.001). The results infer that the wheat, broken rice, DDGS, and wheat bran had no negative effect when replacing 15% corn. Supplementing 0.02% phytase in their diets can effectively optimize nutrient digestibility in yellow broilers.

Effect of Phytase Level and Form on Broiler Performance, Tibia Characteristics, and Residual Fecal Phytate Phosphorus in Broilers from 1 to 21 Days of Age

The present study evaluated the individual and combined effects of coated and uncoated phytase on broiler performance, tibia characteristics, and residual phytate phosphorus (P) in manure. Two repeated studies were conducted using 240-day-old Cobb 500 by-product male broilers per trial. For each trial, birds were assigned to four treatments with four replicate battery cages per treatment (60 birds/trt) and grown for 21 days. Treatments included: (1) negative control (NC), (2) NC + 1000 phytase units (FTU) coated phytase (C), (3) NC + 1000 FTU uncoated phytase (U), and (4) NC + 500 FTU coated + 500 FTU uncoated phytase (CU). Data were analyzed with a one-way ANOVA and means were separated using Tukey’s HSD. In the pooled data for both trials, all treatments with dietary phytase had a higher body weight (BW) and feed consumption (FC) than the NC on day 21 (p < 0.05). Similarly, a six-point reduction was observed for day 1 to 21 feed conversion (FCR) for U and CU (p < 0.05). All treatments with phytase inclusion differed from the NC in every evaluated parameter for bone mineralization (p < 0.05) and had significantly lower fecal phytate P concentrations compared to the NC (p < 0.05). Overall, bird performance was essentially unaffected by phytase form, indicating that combining phytase forms does not appear to offer any advantage to the evaluated parameters from day 1 to 21.

The Duration of the Trial Influences the Effects of Mineral Deficiency and the Effective Phytase Dose in Broilers' Diets

Two trials varying in duration (short- and long-term) were conducted to evaluate the effects of providing deficient (NC) or sufficient (PC) Ca and P levels, and different doses of a new phytase (250, 500, and 1000 FTU/kg feed), in broiler feed on growth performance, nutrient digestibility and retention, and tibia mineralization. A total of 80 and 490 male chicks (Ross) of 21 and 1 days of age were used in the short- and long-term trials, respectively. In the long-term trial, chicks fed NC diets showed a lower (p < 0.05) average daily gain and feed intake compared to chicks fed PC and a greater (p < 0.05) feed conversion ratio compared to 500 and 1000 FTU/kg feed during the starting period. Regarding the effects on minerals’ and nutrients’ coefficients of retention, animals fed NC showed a significantly higher digestibility for P than those fed the PC diet in the long-term trial. Additionally, feeding 250 to 500 FTU/kg diets increased most of the nutrients’ digestibility in the short-term but only P digestibility in the long-term trial. Tibia mineralization increased linearly with phytase addition (p < 0.05) only in the long-term trial. In conclusion, the effects of dietary mineral and phytase levels on growth performance are more noticeable in young animals. In addition, the duration of the trial is key due to a possible adaptation phenomenon of birds to low P supplementary levels.

A time-series effect of phytase supplementation on phosphorus utilization in growing and finishing pigs fed a low-phosphorus diet

Two experiments were carried out to determine a time-series effect of phytase on phosphorus (P) utilization in growing and finishing pigs using growth performance, apparent total tract digestibility (ATTD) of nutrients, P excretion, and plasma concentrations of minerals as the response criteria for evaluation. In both experiments, treatments were arranged as a 3 × 4 factorial in a randomized complete block design with 3 corn-soybean meal-based diets including a P-adequate positive control (PC), a low-P negative control (NC; no inorganic P), and NC supplemented with phytase at 1,000 FYT/kg (NC + 1,000); and 4 sampling time points at days 7, 14, 21, and 28 in experiment 1, and days 14, 26, 42, and 55 in experiment 2. In both trials, 96 growing pigs with average body weight (BW) of 19.8 ± 1.16 and 49.8 ± 3.21 kg, respectively, were allocated to the 3 diets with 8 replicates pens (4 barrows and 4 gilts) and 4 pigs per pen. In experiment 1, pigs fed the PC had higher (P < 0.01) BW, average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F) when compared with pigs fed the NC. There was an interaction (P < 0.01) between time and diet on the BW and ADG of pigs while a linear and quadratic increase (P < 0.01) was observed with the ADFI and G:F, respectively, over time. Phytase supplementation improved (P < 0.01) all growth performance responses. Pigs fed the PC had greater (P < 0.01) ATTD of P and Ca than pigs fed the NC. There was no interaction effect on the ATTD of nutrients. Phytase addition improved the ATTD of P and Ca over pigs fed the NC. There was an interaction (P < 0.01) between diet and time on the total and water-soluble P (WSP) excreted. There was a quadratic decrease (P < 0.01) in plasma concentration of Ca in pigs over time. In experiment 2, there was a quadratic increase (P < 0.01) in BW, ADG, and G:F of pigs over time. Similarly, the inclusion of phytase improved (P < 0.05) all growth performance parameters except ADFI. A linear increase (P < 0.05) in the ATTD of DM, P, and Ca occurred over time. Phytase inclusion improved (P < 0.01) the ATTD of P and Ca. Plasma concentrations of P were improved by phytase addition. Phytase supplementation of the NC reduced WSP excretion by 45%, 32%, and 35% over the growing, finishing, and entire grow-finish period, respectively. In conclusion, phytase improves the utilization of P in growing and finishing pigs; however, the magnitude of effect on responses may vary over time.

Evaluation of the responses of broiler chickens to varying concentrations of phytate phosphorus and phytase. Ⅱ. 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.

Supplemental Effects of Phytase on Modulation of Mucosa-Associated Microbiota in the Jejunum and the Impacts on Nutrient Digestibility, Intestinal Morphology, and Bone Parameters in Broiler Chickens

This study aimed to determine supplemental effects of phytase on modulation of the mucosa-associated microbiota in the jejunum, intestinal morphology, nutrient digestibility, bone parameters, and growth performance of broiler chickens. Three hundred and sixty newly hatched broiler chickens (Ross 308) (44 ± 2 g BW) were randomly allotted in 6 treatments with 10 birds per cage based on a completely randomized design and fed for 27 d. The treatments consisted of one negative control (NC), diet formulated meeting the requirements suggested by Ross recommendations (2019), and without phytase supplementation. The other treatments consisted of a positive control diet (PC) formulated with 0.15% deficient Ca and P and split into 5 treatments with different phytase inclusion levels (0, 500, 1000, 2000, 4000 FTU/kg feed). Titanium dioxide (0.4%) was added to feeds as an indigestible marker to measure apparent ileal digestibility (AID) of nutrients. On d 27, 3 birds were randomly selected from each cage and euthanized to collect samples for analyzing the mucosa-associated microbiota in the jejunum, oxidative stress status, AID, and bone parameters. Data were analyzed using the proc Mixed of SAS 9.4. Phytase supplementation tended to have a quadratic effect (p = 0.078) on the overall ADG (maximum: 41 g/d at 2833 FTU/kg of feed). Supplementation of phytase at 2,000 FTU/kg increased (p < 0.05) the relative abundance of Lactobacillus and reduced (p < 0.05) Pelomonas. Moreover, it tended to reduce Helicobacter (p = 0.085), Pseudomonas (p = 0.090) Sphingomonas (p = 0.071). Phytase supplementation increased (p < 0.05) the villus height and the AID of CP; and tended to increase (p = 0.086) the AID of P. Phytase supplementation increased (p < 0.05) breaking strength and P content in the tibia. In conclusion, phytase supplementation showed potential benefits on the modulation of the mucosa-associated microbiota in the jejunum by tending to reduce harmful bacteria (Pelomonas, Helicobacter, and Pseudomonas) and increase beneficial bacteria (Lactobacillus). In addition, it showed positive effects increasing apparent ileal digestibility of CP and P, enhancing intestinal morphology (villus height), and improving the bone parameters (bone breaking strength, ash, and P content). Phytase supplementation at a range of 38 to 59 FTU/d or 600 to 950 FTU/kg of feed provided the most benefits related to nutrient digestibility.

Evaluation of the responses of broiler chickens to varying concentrations of phytate phosphorus and phytase. Ⅰ. 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.

Additivity of apparent and standardized ileal digestibility of phosphorus in mixed diets containing corn and soybean meal fed to broiler chickens

Phosphorus (P) is an integral part of diet formulation for broiler chickens as P is required for various biochemical processes essential to life. A study was designed to examine the additivity of apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of P in mixed diets containing corn and soybean meal (SBM) with or without phytase supplementation. Birds were fed a commercial starter diet from day 0 to 21 after hatching and then allotted to 7 dietary treatments in a randomized complete block design with the BW as a blocking factor. Four semipurified diets were prepared to contain corn or SBM as the sole source of P with or without the addition of phytase at 1,000 phytase units/kg of diet. Two mixed diets were also prepared to contain corn and SBM with or without the addition of phytase at 1,000 phytase units/kg diet. A P-free diet (PFD) was formulated to determine the basal ileal endogenous loss of P. There were 16 replicate cages of the PFD and 8 replicate cages of the 6 experimental diets, with 8 birds per replicate cage for a total of 512 birds. Diets were fed for 3 d. The ileal digesta of birds were collected from the distal two-thirds of the ileum on day 24 after hatching. The SID of P in corn and SBM were 52.2 and 65.4%, respectively (SEM = 1.37). The addition of phytase improved (P < 0.05) both the AID and SID of P in the corn, SBM, and mixed diets. The determined AID or SID in the corn and SBM with or without phytase was used to predict the AID or SID in the mixed diets. There were no differences between the predicted and determined digestibility values in the mixed diets for either AID or SID of P and thus additive. Phytase supplementation of the mixed diet did not influence the additivity of AID or SID. In conclusion, the AID or SID of P in the corn and SBM was additive in the mixed diets containing corn and SBM with or without the addition of phytase.

Additivity of apparent and standardised ileal digestibility of phosphorus in corn and canola meal mixed diets; basal endogenous loss of phosphorus responses to phytase and age in broiler chickens

1. The additivity of apparent ileal digestibility (AID) and standardised ileal digestibility (SID) of phosphorus (P) in mixed diets containing corn and canola meal (CCM) with or without phytase supplementation and the impact of age on the basal ileal endogenous loss (BEL) of P were investigated in broiler chickens.2. Treatments were arranged as a 2 × 3 × 2 factorial with two ages (13 d or 21 d post hatching), three diets (corn, canola meal, or CCM), and two phytase levels (0 or 1,000 FYT/kg diet) in a randomised complete block design. There were eight or six birds per cage at 13 d and 21 d of age, respectively, and six replicate cages per treatment, with a total of 588 birds. A P-free diet (PFD) treatment was included at each age to determine the basal endogenous loss (BEL) of P.3. Birds were fed a commercial starter diet from d 1 to d 10 or d 18 and then fed the experimental diets for 3 d until d 13 or d 21, respectively. Predicted digestibility values calculated from the individual feed ingredients were used to test additivity in the mixed diets. Chromium oxide was included in diets as an indigestible marker.4. The ileal digesta, collected from birds at d 13 or d 21, was used to determine nutrient digestibility.5. The AID and SID of P at d 13 was higher (P < 0.01) when compared with older birds at d 21, regardless of dietary phytase supplementation. Regardless of age or phytase supplementation, AID and SID of P were additive, as there were no differences between predicted and determined values in the mixed diets. The BEL of P (g/kg DM intake) in birds at d 13 was higher (P < 0.05) than birds at d 21 (0.197 vs. 0.159).6. In conclusion, age had an impact on the BEL of P and the utilisation of minerals in the diets. The apparent and standardised ileal digestibility of P in the mixed diet containing corn and canola meal were additive, regardless of age or phytase supplementation.

Response of broiler chickens in the starter and finisher phases to 3 sources of microbial phytase

A broiler chicken study was conducted for 42 D to evaluate their responses to 3 commercially available microbial phytases. Growth performance, nutrient digestibility, and bone mineralization at days 21 and 42 posthatching were used as parameters of evaluation. The study was a randomized complete block design with 12 treatments, 8 replicate pens, and 25 birds per pen. Treatments included a positive control (PC), a negative control (NC) with crude protein (CP), nonphytate phosphorus (P), and calcium (Ca) reduced by 18, 1.5, and 1.8 g/kg, respectively; the NC + 4 levels of phytase A (250, 500, 750, 1,000 FTU/kg), 3 levels of phytase B (250, 500, 750 FTU/kg), and 3 levels of phytase C (500, 750, 1,000 FTU/kg). Broilers fed the NC diet had reduced (P < 0.05) performance and digestibility measures at days 21 and 42 relative to the PC. All phytase enzymes improved (P < 0.05) BW, gain, feed efficiency, and tibia ash weight and percent. Inclusion of phytase at the highest levels improved (P < 0.05) tibia ash weight by an average of 18.5 and 22% at days 21 and 42, respectively, over the NC. Phytase A linearly improved (P < 0.05) the apparent ileal digestibility (AID) of DM, Ca, P, copper, and sodium at day 21, and the AID of energy, nitrogen, and all amino acid (AA) digestibility at day 42 posthatching. Phytase B linearly (P < 0.05) improved BW gain and feed efficiency of birds at day 21 and quadratically improved (P < 0.05) the AID of nitrogen and all AA in birds at day 42. Supplementation of birds fed the NC with phytase C linearly improved (P < 0.05) the BW gain, feed intake, feed efficiency, and AID of DM, energy, nitrogen, all AA, and all minerals except manganese at day 42. In conclusion, all 3 phytase products improved the growth performance, nutrient and mineral digestibility, and bone mineralization of birds fed diets deficient in nitrogen, Ca, and P similar to or more than birds fed diet adequate in P and CP.