Tibia Ash Research Articles

Phytase and nutrient-energy matrix: a strategic approach to enhancing the performance of broiler chickens fed a corn-soybean meal-based diet.

This study examined the effects of a nutrient matrix with or without phytase on the performance of broiler chicken. A total of 2000 day-old Ross 308 broiler chickens were assigned to 5 dietary treatments, with 10 broilers per replicate and 40 replicates per treatment. The experimental diets included 1. CON: A corn and soybean meal (SBM)-basal diet without phytase. 2, NC1: A corn-SBM-based diet with reduced nutrients, specifically 0.13% less phosphorus, 40 Kcal/kg less metabolizable energy (ME), and 0.30% less crude protein (CP), without phytase. 3, NC1+PHYT: NC1+500 FTU/kg phytase. 4, NC2: Another corn-SBM-based diet with greater nutrient reductions, including 0.16% less phosphorus, 55 Kcal/kg less metabolizable energy (ME), and 0.45% less crude protein (CP), without phytase. 5, NC2+PHYT: NC2+1000 FTU/kg phytase. In the pre-starter and overall phase, feed conversion ratio (FCR) was higher in NC2 and NC2+PHYT. In the starter phase, body weight gain (BWG) was lower in NC2 and NC2+PHYT. In the grower phases, BWG was lower in NC2, while FCR was higher. At d28, the digestibility of ash was higher in NC1+PHYT, while the digestibility of Ca and phosphorus were higher in NC1+PHYT and NC2+PHYT. At day 42, the digestibility of ash, Ca, and phosphorus were higher in NC1+PHYT and NC2+PHYT. The level of tibia ash was lower in NC2. The level of myo-inositol was lower in NC2 at d28, while the level of myo-inositol at d42 was lower in NC1 and NC2. We concluded NC1+PHYT showed a higher growth performance comparable to CON, as against the lower performance observed in NC2, NC2+PHYT, and NC1.

The optimal dietary sodium and chloride level for broiler chicks fed a corn-soybean meal diet between 1 and 21 days of age.

The experiment was conducted to estimate the ideal dietary sodium (Na) and chloride (Cl) level for broilers during d 1 to 21 using a corn-soybean meal diet under a dietary Na:Cl ratio of 1:1. A total of 490 one-d-old Arbor Acres male broilers were randomly allotted by bodyweight to 1 of 7 treatments in a completely randomized design. Each treatment consisted of 7 replicate cages with 10 chicks per cage. Broilers were fed a Na and Cl-unsupplemented corn-soybean meal basal diet (control, containing 0.02% Na and 0.08% Cl) and the Na and Cl-supplemented basal diets containing 0.14%, 0.20%, 0.26%, 0.32%, 0.38% and 0.44% Na and Cl levels, respectively for 21 d. The results indicated that average daily gain, average daily feed intake, blood partial pressure of CO2 and concentrations of HCO3-, total CO2, Na+, Cl-, base excess and anion gap, tibial ash and ash Na contents of broilers were affected (P < 0.001) by dietary Na and Cl level, and increased linearly (P < 0.001) and quadratically (P < 0.001) with increasing Na and Cl levels. Feed/gain ratio, mortality, blood K+ concentration, serum osmotic pressure and K+, glucose and uric acid concentrations as well as heart, liver and kidney indices of broilers were affected (P < 0.01) by dietary Na and Cl level, and decreased linearly (P < 0.001) and quadratically (P < 0.001) with increasing Na and Cl levels. The estimates of dietary optimal Na and Cl levels were 0.07%-0.16% according to the best fitted broken-line or asymptotic models (P < 0.001) of the above sensitive indicators. Therefore, the optimal dietary Na and Cl level was suggested to be 0.16% to support all of the above Na and Cl metabolic requirements of broilers fed the corn-soybean meal diet during d 1 to 21, which is lower than the recommendation at 0.20% by the Chinese Feeding Standard of Chicken (2004).

Potential benefits of advanced chelate-based trace minerals in improving bone mineralization, antioxidant status, immunity, and gene expression modulation in heat-stressed broilers.

Organic sources of trace minerals (TM) in broiler diets are more bioavailable and stable than inorganic sources, making them particularly beneficial during challenging periods such as heat stress (HS) conditions. A 42-d study investigated the effects of using advanced chelate technology-based TM (ACTM) or adding varying amounts of ACTM to broiler diets during HS conditions. The study involved 672 male broiler chickens in 7 treatment groups, including a thermoneutral control (TNC) group and six HS treatments. There were 8 replicate pens per treatment and 12 birds per replicate. The six HS treatments included birds exposed to a cyclic HS environment (34°C) for 8 h and were as follows: HSC, which consisted of the same basal diet with the recommended ITM levels; ACTM50 and ACTM100, which replaced the basal diet with 50% and 100% ACTM instead of ITM; ITM+ACTM12.5 and ITM+ACTM25, which involved adding extra ACTM to the ITM basal diet at 12.5% and 25%, respectively; and ITM125, which used 125% of the recommended levels of ITM in the basal diet. Compared with the HSC treatment, the TNC, ACTM100, and ITM+ACTM25 treatments resulted in increased (P < 0.05) body weight; tibia weight; tibia ash, phosphorus, iron, and manganese contents; secondary antibody titers; and serum TAC and SOD values but decreased (P < 0.05) serum MDA concentrations and the expression levels of the hepatic genes IL-1β, IL-6, and INF-γ. The TNC and ACTM100 groups also showed greater (P < 0.05) feed efficiency, tibia length, tibia zinc content, and hepatic SOD1 expression but exhibited reduced (P < 0.05) hepatic NF-kB expression. Significant increases (P < 0.05) in primary anti-NDV titers, serum GPx1 activity, and Nrf2 and GPx1 gene expression levels were also detected in the ACTM100, ITM+ACTM12.5, and ITM+ACTM25 groups. In conclusion, the findings suggest that replacing ITM with ACTM or adding ACTM to ITM diets, especially at a 25% higher dose, can effectively protect broilers from heat stress by promoting growth, reducing inflammation, and increasing the expression of antioxidant proteins.

Comparative impact of conventional and alternative gut health management programs on plasma and tibia attributes in broiler chickens raised in commercial and research settings

Plasma and tibia attributes were investigated in broiler chickens raised on three gut health management programs in commercial farms (study 1) and research station settings (study 2). The programs were: 1) conventional antibiotics (CON), 2) raised without medically important antimicrobials (RWMIA), and 3) raised without antibiotics (RWA). Birds had free access to feed and water from placement to harvest; samples of blood and left tibia were collected on d 28 in both studies and further samples were taken on d 41 in study 2. In both studies, there were no program differences (P &gt; 0.05) on plasma metabolites with exception of enzyme concentrations with notably higher levels of circulating plasma alkaline phosphatase (ALP) in birds reared on the RWA program (P ≤ 0.04). Differences were observed among programs for tibia length in both studies (P &lt; 0.05). Birds reared on RWMIA exhibited significantly (P = 0.016) higher tibia ash than CON on d 41. Observed differences in the plasma enzyme concentrations, tibia length, and ash concentration suggest altered metabolism which could be linked to gut health management programs and their ability to support gut integrity and function in the absence of antibiotics.

Unlocking Phytate with Phytase: A Meta-Analytic View of Meat-Type Chicken Muscle Growth and Bone Mineralization Potential.

The inclusion of exogenous phytase in P- and Ca-deficient diets of broilers to address the growing concern about excessive P excretion into the environment over the years has been remarkably documented. However, responses among these studies have been inconsistent because of the several factors affecting P utilization. For this reason, a systematic review with a meta-analysis of results from forty-one studies published from 2000 to February 2024 was evaluated to achieve the following: (1) quantitatively summarize the size of phytase effect on growth performance, bone strength and mineralization in broilers fed diets deficient in P and Ca and (2) estimate and explore the heterogeneity in the effect size of outcomes using subgroup and meta-regression analyses. The quality of the included studies was assessed using the Cochrane Collaboration's SYRCLE risk of bias checklists for animal studies. Applying the random effects models, Hedges' g effect size of supplemented phytase was calculated using the R software (version 4.3.3, Angel Food Cake) to determine the standardized mean difference (SMD) at a 95% confidence interval. Subgroup analysis and meta-regression were used to further explore the effect size heterogeneity (PSMD ≤ 0.05, I2 > 50%, n ≥ 10). The meta-analysis showed that supplemental phytase increases ADFI and BWG and improves FCR at each time point of growth (p < 0.0001). Additionally, phytase supplementation consistently increased tibia ash, P and Ca, and bone strength (p < 0.0001) of broilers fed P- and Ca-deficient diets. The results of the subgroup and meta-regression analyses showed that the age and strain of broiler, dietary P source, and the duration of phytase exposure significantly influence the effect size of phytase on growth and bone parameters. In conclusion, phytase can attenuate the effect of reducing dietary-available phosphorus and calcium and improve ADFI, BWG, and FCR, especially when added to starter diets. It further enhances bone ash, bone mineralization, and the bone-breaking strength of broilers, even though the effects of bone ash and strength can be maximized in the starter phase of growth. However, the effect sizes of phytase were related to the age and strain of the broiler, dietary P source, and the duration of phytase exposure rather than the dosage.

Effect of Genistein and Glycitein on production performance, egg quality, antioxidant function, reproductive hormones and related-genes in pre-peak laying hens

Genistein (GEN) and Glycitein (GLY), are types of isoflavone extracted mainly from soy plants, although GEN is associated with stronger antioxidant and growth-promoting effects. The impact of dietary GEN and GLY on reproductive performance, egg quality, and bone quality were investigated in the study. Additionally, to explore the underlying mechanism of action, the serum hormone levels and reproductive-related genes were investigated. A total of 378 Hy-Line Brown laying hens (120 days old) were randomly allocated to 3 dietary groups (Control), (GLY, and GEN at 50 mg/kg respectively) for a period of 8 wk. Each treatment has 126 birds (7 replicates of 18 birds each). Results were analyzed in 2 phases: wk 1 to 4, and 5 to 8 of feeding trial. The results indicated that supplemental GEN significantly increased egg number, hen-day production (HDP), and egg mass during wk 1 to 4, whereas, both glycitein and genistein increased egg number, egg weight, egg mass, HDP and improved feed-egg-ratio during wk 5 to 8. Egg quality analysis revealed significant improvements in eggshell quality; gloss, thickness, strength, and albumen quality indices (albumen height, Haugh unit, thick albumen fraction) due to dietary treatments. Also, the tibia strength, Ca content in the tibia ash and bone mineral content, were significantly increased by the dietary treatments. Significant increases in the serum levels of E2, LH, FSH, T3, T4, and GH, and the activity of antioxidant enzymes; SOD, CAT, GSH while reducing the level of MDA, was notable with the treatments. Additionally, reproductive-related genes: ESR1, FSHR, PRLR, GNRH1 were significantly upregulated by the supplementation of GEN and GLY. The efficacy of GEN in relation to the evaluated parameters was superior to that of GLY. Conclusively, we speculate that the improvement on laying performance, egg quality and tibia quality may be related to promoting effect of isoflavones on calcium metabolism, antioxidant function, reproductive hormones and related genes. Therefore, supplemental GEN at a dosage level of 50 mg/kg, can be used to promote laying performance, sustain egg production and maintain the physiological function of young laying hens.

Dietary Clostridium butyricum and 25-Hydroxyvitamin D3 modulate bone metabolism of broilers through the gut—brain axis

Leg disorders have become increasingly common in broilers, leading to lower meat quality and major economic losses. This study evaluated the effects of dietary supplementation with Clostridium butyricum (C. butyricum) and 25-hydroxyvitamin D3 (25-OH-D3) on bone development by comparing growth performance, tibial parameters, Ca and P contents of tibial ash, bone development-related indicators' level, and cecal short-chain fatty acids in Cobb broilers. All birds were divided into four treatment groups, which birds fed either a basal diet (Con), basal diet + 75 mg chlortetracycline/kg (Anti), basal diet + C. butyricum at 109 CFU/kg (Cb), basal diet + C. butyricum at 109 CFU/kg and 25-OH-D3 at 25 μg/kg (CbD), or basal diet + 25-OH-D3 at 25 μg/kg (CD). Our results suggest that the dietary supplementation in Cb, CbD, and CD significantly increased the body weight (BW) and average daily gain (ADG), and reduced the feed-to-weight ratio (F/G) at different stages of growth (P < 0.05). Dietary supplementation in Cb, CbD, and CD prolonged (P < 0.05) the behavioral responses latency-to-lie (LTL) time, reduced (P < 0.05) the levels of osteocalcin (BGP) and peptide tyrosine (PYY), and increased (P < 0.05) serotonin (5-HT) and dopamine (DA). Treatment with Cb increased (P < 0.05) the levels of acetic acid, isobutyric acid, butyric acid, and isovaleric acid compared with those in Con group. The cecal metagenome showed that Alistipes spp. were significantly more abundant in Cb, CbD, and CD groups (P < 0.05). A total of 12 metabolic pathways were significantly affected by supplementation, including the signaling pathways of glucagon, insulin, and PI3K-AKT; primary and secondary bile acid biosynthesis; and P-type Ca 2+ transporters (P < 0.05). Hence, the CbD supplementation modulates bone metabolism by regulating the mediators of gut-brain axis, which may inform strategies to prevent leg diseases and improve meat quality in broilers.

Evaluation of Boron as a Feed Additive to Improve Musculoskeletal Health of Hy-Line W-36 Pullets

Boron supplementation may improve the musculoskeletal health of pullets before entering the lay phase. This study aimed to evaluate the effects of different boron amounts on the performance, muscle deposition, tibia cross-sectional area (CSA) and mineral density (BMD), ash percent, breaking strength, and bone mineralization (bone-specific alkaline phosphatase [BALP] and pro-collagen type 1 n-terminal propeptide [P1NP]) of a white-feathered strain of pullets. A total of 528 Hy-Line W-36 pullets were distributed across 24 pens and fed basal diets containing varying amounts of boron (C: 0 mg/kg; L: 50 mg/kg; M: 100 mg/kg; H: 150 mg/kg) for 17 weeks. Performance parameters (body weight, average daily weight gain/bird, and average daily feed intake/bird) were measured at weeks 4, 7, 10, 13, and 16, while all other measures were taken at 11 and 17 weeks of age. Performance was not impacted by boron supplementation. Pectoralis major weights were higher in H pullets at 11 weeks of age, and we also observed higher pectoralis major, minor, and leg muscle weights in H pullets at 17 weeks of age. Pullets fed the H diet had larger cortical CSA than the other treatment groups at 11 weeks of age. At 17 weeks of age, both the H and M groups had larger cortical CSA than the L and C groups, but the M group had slightly smaller cortical CSA. Pullets fed the H diet had higher BMD values than the other treatment groups at 11 weeks of age. At 17 weeks of age, pullets fed the H diet had the highest total BMD values compared to the other treatment groups, and cortical BMD increased with increasing boron inclusion. Pullets fed the H diet had the highest tibia ash percentages and concentrations of BALP and P1NP. Pullets fed the M and H diets had greater failure load and maximum bending moment than pullets fed the L or C diet at 11 weeks of age, with H pullets having greater stiffness values than other groups. At 17 weeks of age, pullets fed the H diet had greater failure load and maximum bending moment compared to all other treatment groups. Our results suggest that providing boron within the diet at 150 mg/kg can improve the musculoskeletal characteristics of Hy-Line W-36 pullets up to 17 weeks of age, without impacting performance parameters.

Effect of corn–soybean meal-based diets with low calcium and available phosphorus in male broilers on performance, tibia criteria and jejunum histomorphology

Abstract This study was conducted to determine the effect of reducing calcium (Ca) and available phosphorus (AvP) on performance, carcass yield, tibia traits and jejunum histomorphology in broilers. For this purpose, 480 one-day-old Ross 308 male chicks were distributed into four trial groups with eight subgroups. During the starter period, birds were fed with recommended or reduced Ca and AvP contents of 66.7 and 62.5 g/kg, respectively. Calcium and AvP contents of the groups were as follows: control: 8.70 g/kg Ca, 4.40 g/kg AvP for grower and 7.80 g/kg Ca, 3.90 g/kg AvP for finisher; LCP1: 8.30 g/kg Ca, 4.20 g/kg AvP for grower and 7.10 g/kg Ca, 3.50 g/kg AvP for finisher; LCP2: 7.90 g/kg Ca, 4.00 g/kg AvP for grower and 6.00 g/kg Ca, 3.00 g/kg AvP for finisher; LCP3: 7.00 g/kg Ca, 3.80 g/kg for grower and 5.00 g/kg Ca, 3.00 g/kg AvP for finisher. Performance variables have been calculated from the data of each period, and samples were obtained from the slaughtered birds on the final day of the trial (42nd day) for carcass and tibia traits and jejunum histomorphology. Reducing dietary Ca and AvP did not affect the broiler performance, carcass yield and mortality. Tibia ash decreased in LCP2 and LCP3 groups (P &lt; 0.01). Villus width and villus surface area increased in LCP2 and LCP3. Overall, feeding with a diet 100 g/kg lower than the recommended Ca and AvP did not affect performance in broilers, but improved jejunal development.

PSVI-15 Assessing the implications of a silymarin-enriched diet on the performance and blood absorption rate of broiler and laying hen

Abstract This experiment was executed to assess the impacts of silymarin on different aspects of broiler and laying hen, including growth, digestibility, excreta score, footpad lesion score, tibia ash, meat quality, and blood absorption rate. In Experiment 1: 1-d-old Ross 308 broilers (mixed sex; n = 576) were arbitrarily assigned with an average body weight of 42 ± 0.3 g for a 32-d trial. The broilers were sorted into eight repetition pens with 18 birds per pen and four research treatments (basal diet as the control and basal diet included 0.02, 0.04, and 0.06% micelle silymarin). Experiment 2: 61-wk-old Hy-line brown laying hens (n = 16) were divided into 2 treatment groups (TRT1, basal diet + powdered silymarin 4%; TRT2, basal diet + micelle silymarin 4%), with 8 numbers per repetition. Feeding broilers with a graded dose of micelle silymarin (MS) increased body weight gain linearly during d 1–9, 9–21, 21–32, and overall (P = 0.021, 0.011, 0.019, and 0.002, respectively). Furthermore, there was a linear increase in feed intake (P = 0.017) during d 1–9, and the enhancement of dry matter utilization (linear, P = 0.011) was exhibited as the amount of MS inclusion in the diet increased. Tibia ash content enhanced linearly (P = 0.038), and meat quality traits also revealed a linear improvement in breast muscle color (yellowness) (P = 0.045) and linear decrease (P = 0.004) in pH level with the increasing levels of MS in the broiler diet. Nonetheless, both the excreta score and the footpad lesion score showed no significant alteration (P &amp;gt; 0.05). Moreover, a greater absorption rate of silymarin was observed in the blood of laying hens 2 h (P &amp;lt; 0.0001) and 4 h (P &amp;lt; 0.0001) after feeding with micelle-type silymarin as compared with powdered-type silymarin. Briefly, MS can be a favorable supplement for poultry production as it can increase the growth, digestibility, toe ash, and meat quality of broilers and the blood absorption rate of laying hens.

Two studies evaluated the effects of a novel consensus bacterial 6-phytase variant on the growth performance of broilers fed corn/soybean diets and deficient in nutrients and energy

Two experiments were conducted to evaluate the effects of a novel consensus bacterial 6-phytase variant (PhyG) on performance of broilers fed US type diets with reduced nutrients and energy. Each experiment utilized a completely randomized block design where four treatments were tested with 10 replicate groups, each treatment totaling 270 day-of-hatch male Ross 308 broilers. The diets were: 1), a nutrient-adequate control (PC) and 2), a nutrient and energy-reduced negative control (NC): PC minus 0.19 % avP, 0.23 % Ca, 0.045 % Na, up to 0.05 % unit dig AA and 37 kcal/kg ME and 3), NC with PhyG supplemented at 1,500 FTU/kg (PhyG1500) 4), PC minus 0.164 % avP, 0.201 % Ca, 0.037 % Na, up to 0.035 %-unit dig. AA and 29 kcal/kg ME plus the PhyG at 750 FTU/kg (PhyG750). Xylanase was included in all diets at 750 XU/kg with 25 kcal/kg of ME matrix applied. Experiment 1 diets (wholly vegetable) were based on corn-soybean meal with <2 % DDGs. Experiment 2 diets (conventional) were based on corn-soybean meal with <3 % DDGS and <4 % meat and bone meal. Diets were pelleted and fed ad libitum over four phases: starter (1–10d), grower (11–21d), finisher 1 (22–35d), and finisher 2 (36–42d). In both experiments, compared with PC, birds fed the nutrient and energy reduced NC exhibited reduced 42d BW and increased overall 1–42d FCR (P < 0.05). During all phases, in both experiments, PhyG at each dose-level produced growth performance measures that were by phase and cumulatively equivalent to PC. PhyG at 1500 FTU improved accumulative FCR (1–21d, 1–35d and 1–42d) in experiment 1, and 1–21d FCR in experiment 2 compared to PC. Similarly, PhyG750 and PhyG1500 increased (P < 0.05) tibia ash and carcass yield vs. NC to similar levels as PC. For all measures, response values were numerically highest with 1500 FTU/kg. In conclusion, the novel consensus phytase variant completely compensated for the reduction in avP, Ca, Na, dig AA, and ME respectively at each dose-level and maintained growth performance, carcass characteristics, and bone quality of broilers fed wholly vegetable or conventional US type commercial diets through 42 days of age, leading to reduced feed cost and production benefit.

Enhancing calcium and phosphorus utilization in broiler chickens through cholecalciferol in sequential calcium-phosphorus-deficient diets

ABSTRACT We hypothesized that both performance and bone mineralization would show improvements when cholecalciferol supplementation was increased above the recommended NRC (1994) [Nutrient requirements of poultry, 9th rev. ed. Washington, DC: National Academy Press] level. In this study, male Ross 308 chickens (n = 540) were supplemented with diets containing either a low level of 200 IU/kg or a higher dose of 5,000 IU/kg of cholecalciferol (VD). The results showed that during the starter phase, weight gain was significantly higher in VD5000 and the control compared to VD0, with significantly lower feed intake in VD0. Consequently, FCR was significantly better in VD200 and VD5000 compared to VD0. In the finisher phase, weight gain, feed intake, and FCR were significantly higher in VD200 and VD5000 compared to VD0. Tibia ash, Ca, and P were significantly higher in VD5000 compared to VD200. Carcass weight was significantly higher in VD200 and VD5000 compared to VD0. Total tract N retention and GE were significantly higher in VD5000 compared to VD0. The study concludes that cholecalciferol supplementation at 5000 IU/kg enhances growth performance, tibia mineralization, and nutrient digestibility in broilers fed with 30% reduced Ca and P in their diets.

Effect of baker's yeast fermented moist feed on the growth and bone mineralization in broiler.

The effect of feeding yeast-fermented feed in various forms on broiler growth performance and bone mineralization was studied. Initially, a corn-soy-based diet was formulated and fermented in anaerobic conditions at 28°C in laboratory space for 48 h with yeast (2.0%) and moisture (50%). Afterward, the 150 newly hatched Arbeor Acres commercial broiler chicks were divided into 5 dietary groups (30 chicks, 6 cages, and 5 birds per cage). Each group received one of the following formulated and fermented diets: dry feed (DF), moist feed (MF), yeast-added dry feed (Y-DF), yeast-added moist feed (Y-MF), or yeast-fermented moist feed (YF-MF). Water and feed were supplied ad libitum. Six birds per group were slaughtered at age 37 for the determination of carcass traits and tibia ash. Fermentation improved crude protein from 20.7% to 22.8% but declined crude fiber from 7.9% to 6.3% in the YF-MF group compared to the DF group. High body weight gain was recorded in 771, 830, and 992 gm in the MF, Y-MF, and YF-MF groups, respectively, compared to the DF (762 gm) group (p < 0.01). The feed conversion ratio was better in the Y-MF (1.57) and YF-MF (1.57) groups than in the DF (1.75) group. Feeding a fermented, moist diet resulted in improved carcass yield (69%) in the YF-MF group. Bone mineralization expressed a better tibia ash percentage (35% from 30%) in the YF-MF group compared to the DF group. Therefore, YF-MF enhanced the quality of feed and improved growth, carcass weight, and bone mineralization in broiler.

Impact of Trace Mineral Source and Phytase Supplementation on Prececal Phytate Degradation and Mineral Digestibility, Bone Mineralization, and Tissue Gene Expression in Broiler Chickens

The objective of this study was to determine how different sources of Zn, Mn, and Cu in the feed without and with phytase affect prececal myo-inositol hexakisphosphate (InsP6) breakdown to myo-inositol (MI), prececal P digestibility, bone mineralization, and expression of mineral transporters in the jejunum of broiler chickens. A total of 896 male broiler chicks (Cobb 500) were distributed to 7 diets with 8 replicate pens (16 birds per floor pen). Experimental diets were fed from day 0 to 28. Diets were without or with phytase supplementation (0 or 750 FTU/kg) and were supplemented with three different trace mineral sources (TMS: sulfates, oxides, or chelates) containing 100 mg/kg Zn, 100 mg/kg Mn, and 125 mg/kg Cu. Prececal InsP6 disappearance and P digestibility were affected by interaction (phytase × TMS: P ≤ 0.010). In diets without phytase supplementation, prececal InsP6 disappearance and P digestibility were greater (P ≤ 0.001) in birds fed chelated minerals than in birds fed sulfates or oxides. However, no differences were observed between TMS in diets with phytase supplementation. Ileal MI concentration was increased by exogenous phytase but differed depending on TMS (phytase × TMS: P ≤ 0.050). Tibia ash concentration as well as Zn and Mn concentration in tibia ash were increased by phytase supplementation (P < 0.010), but the Cu concentration in tibia ash was not (P > 0.050). Gene expression of the assayed mineral transporters in the jejunum was not affected by diet (P > 0.050), except for Zn transporter 5 (phytase × TMS: P = 0.024). In conclusion, the tested TMS had minor effects on endogenous phytate degradation in the digestive tract of broiler chickens. However, in phytase-supplemented diets, the choice of TMS was not relevant to phytate degradation under the conditions of this study.

Impact of Perch Provision Timing on Activity and Musculoskeletal Health of Laying Hens.

Laying hens can experience a progressive increase in bone fragility due to the ongoing mobilization of calcium from bones for eggshell formation. Over time, this escalates their susceptibility to bone fracture, which can reduce their mobility and cause pain. The provision of perches as an exercise opportunity could potentially enhance bone strength, but the timing of exposure to perches during the birds' development may modulate its impact. The objective of this study was to investigate the enduring impacts of perch provision timing on the musculoskeletal health of laying hens. A total of 812 pullets were kept in different housing conditions (seven pens/treatment, 29 birds/pen) with either continuous access to multi-tier perches from 0 to 40 weeks of age (CP), no access to perches (NP), early access to perches during the rearing phase from 0 to 17 weeks of age (EP), or solely during the laying phase from 17 to 40 weeks of age (LP). At weeks 24, 36, and 40 of age (n = 84 birds/week), three birds per pen were monitored for individual activity level, and blood samples were collected from a separate set of three birds per pen to analyze serum levels of tartrate-resistant acid phosphatase 5b (TRACP-5b) and C-terminal telopeptide of type I collagen (CTX-I) as markers of bone demineralization. At 40 weeks of age, three birds per pen (n = 84) were euthanized for computed tomography scans to obtain tibial bone mineral density (BMD) and cross-sectional area (CSA) with further analysis including muscle deposition, tibial breaking strength, and tibial ash percent. During week 24, hens from CP, EP, and LP pens had the highest overall activity compared to hens from NP pens (p < 0.05) with no differences between treatments for overall activity level during weeks 36 or 40 (p > 0.05). During weeks 24, 36, and 40, hens from CP and LP pens showed greater vertical and less horizontal activity compared to hens from EP and NP pens (p < 0.05). TRACP-5b and CTX-I concentrations did not differ between treatments at week 24 of age (p > 0.05). Hens from CP pens had the lowest TRACP-5b and CTX-I concentrations at 36 weeks of age with EP and LP hens showing intermediate responses and NP hens having the highest concentration (p < 0.05). At 40 weeks of age, CP hens had the lowest TRACP-5b and CTX-I concentrations compared to NP hens (p < 0.05). Total bone CSA did not differ between treatments (p > 0.05), but CP had greater total BMD than NP (p < 0.05) with no differences between EP and LP treatments. CP and LP hens had larger biceps brachii, pectoralis major, and leg muscle groups as well as greater tibial breaking strengths than EP and NP treatments (p < 0.05). CP hens had higher tibial ash percentages compared to EP, LP, and NP (p < 0.05). Our results indicate that providing continuous perch access improves the musculoskeletal health and activity of laying hens at 40 weeks of age compared to no access and that late access to perches has a beneficial impact on activity, muscle deposition, and bone strength.

Dietary supplementation with xylanase suppresses the antinutritional effect of nonstarch polysaccharides of flaxseed and increases bone strength in broiler chickens.

The aim of this study was to determine the effects of xylanase and flaxseed the performance of chickens, digesta viscosity, nutrient retention, fatty acid profile in muscle, tibia strength and interrelations of these factors in broiler chickens fed a wheat-based diet. Seven hundred and twenty one-day-old Ross 308 cockerels were assigned to four treatments according to the contents of flaxseed (0 and 80 g/kg) and xylanase (0 and 0.1 g/kg) in the diet. Xylanase significantly decreased the intake of feed (p < 0.001), decreased feed conversion (p < 0.001), and reduced mortality (p = 0.050). In addition, xylanase significantly increased the retention of all nutrients (p = 0.010 -<0.001) except crude fibre, the fat content in breast meat (p = 0.029) and liver (p = 0.019) and the concentration of polyunsaturated fatty acids (PUFAs) in meat (p = 0.002). Flaxseed supplementation did not influence performance but decreased the retention of dry matter (p = 0.016), crude protein (p = 0.012), organic matter (p = 0.016) and nitrogen-free extract (p = 0.008). Xylanase in combination with flaxseed increased the content of n-3 fatty acids in the breast meat (p = 0.006). The lowest n-6/n-3 ratio (p = 0.001) was detected in the flaxseed and flaxseed combined with xylanase groups. Significant interaction effects of flaxseed and xylanase on tibia strength (p = 0.030) and tibia ash content (p = 0.009) were detected. The administration of xylanase or flaxseed alone increased tibia strength. Compared with the control diet, the addition of flaxseed to the diet increased the digesta viscosity (p = 0.043) in the ileum, whereas the addition of xylanase decreased the level of this indicator. It can be concluded that xylanase is an enzyme suitable for increasing nutrient availability, and in the case of its addition to a flaxseed diet, it can reduce the antinutritional effect of flaxseed by reducing the viscosity of the digesta and increasing the content of health-promoting n-3 PUFAs.

Effect of an Escherichia coli-derived phytase and a carbohydrase-protease cocktail derived from Bacillus spp. on performance, digestibility, bone mineralization and gut morphology in broilers fed different nutrient density diets.

Enzyme combinations, particularly phytase (PHY) with various carbohydrases and proteases, are utilized in commercial broiler production to enhance nutrient and energy bioavailability. A feeding study was undertaken to determine whether the efficiency of an Escherichia coli-derived PHY and a feed enzyme complex (FEC) derived from Bacillus spp. containing carbohydrase and protease as main activities in broiler chickens is dependent on diet quality. A total of 900 male one-day-old broiler chickens (Ross 308) were assigned to a 2×3 factorial arrangement of the treatments with 2 different nutrient density diets, standard nutrient diet (SN diet) and a low-nutrient diet (LN diet; -100kcal/kg for AMEn and -5% for crude protein [CP] and limiting amino acids), and 3 enzyme treatments (control [no enzymes], PHY and PHY+FEC). Each treatment group was composed of 6 replicates of 25 birds each. The LN diet caused a decrease in performance index, tibia length and diameter, tibia calcium content and jejunal villus surface area (VSA). The interaction effects between diet and enzyme supplementation were observed (p<0.05) on overall average daily gain (ADG), performance index, tibia ash content and jejunal villus height (VH) and VSA, with the favourable benefits of PHY+FEC treatment being more pronounced in the LN diets. Regardless of dietary nutrient density, supplementation with PHY alone or combined with FEC enhanced (p<0.05) final body weight, overall ADG and jejunal villus height (VH)/crypt depth, with the highest values observed in the PHY+FEC group. The PHY+FEC treatment also improved (p<0.05) overall feed conversion ratio, apparent ileal digestibility of dry matter, organic matter, CP, and energy, and tibia phosphorus content compared to the control treatment. The results indicate that the simultaneous addition of PHY and FEC to the LN diets improved the growth rate, bone mineralization and gut morphology.

Determination of the standardized ileal digestible calcium requirement of Ross broilers from hatch to day 14 post-hatch

An experiment was conducted to determine the standardized ileal digestible (SID) calcium requirement of fast-growing broilers from hatch to d 14 post-hatch. Ross 308 (n = 360) male broilers were obtained on day of hatch and allocated to 1 of 5 treatments in battery cages. There were 6 birds per cage and 12 pens per treatment. Four treatments were formulated to contain 0.60%, 0.46%, 0.32% or 0.18% SID Ca. The final treatment was formulated using total Ca to meet or exceed all nutrient requirements, including 0.90% total Ca and 0.49% non-phytate P (nPP), using the same ingredients. This treatment was the reference diet for comparison and validation of the SID Ca diets. Birds and feed were weighed at placement and on d 14. Tibias and ileal contents were obtained on d 14 and excreta was collected per pen and pooled on d 14. Data were analyzed using JMP Pro and requirements were estimated using 3 different non-linear regression models. Increasing the SID Ca content in the diet from 0.18% to 0.60% improved (quadratic, P < 0.05) body weight gain and mortality corrected feed conversion ratio (mFCR). The estimated SID Ca requirement to optimize gain or mFCR was between 0.39% and 0.52%. Tibia ash percent and weight increased (quadratic, P < 0.05) as SID Ca content in the diet increased and the estimated SID Ca requirement was between 0.32% and 0.58%. Phosphorus utilization was improved in birds fed diets formulated using SID Ca compared with birds fed the reference diet. In conclusion, the SID Ca requirement of fast-growing broilers from hatch to d 14 was estimated between 0.534% and 0.398% when quadratic, straight-broken line, or quadratic-broken line regressions were used. These results agree with previously published data evaluating the SID Ca requirement of fast-growth broilers from hatch to d 10.

Research Note: Relative bioavailability of zinc in zinc hydroxychloride for chicks

A chick assay was conducted to determine the effects of Zn source on performance and to establish a Zn relative bioavailability value (RBV) for a new source of Zn hydroxychloride. In the assay, 8-day-old chicks were fed a Zn-deficient soy protein concentrate diet supplemented with 0, 7, and 15 mg Zn/kg from feed grade ZnSO4 monohydrate for 14 d to establish a standard response curve. The same basal diet was supplemented with 3, 7, and 10 mg Zn/kg from a new Zn hydroxychloride (SAMZn). A second source of Zn hydroxychloride (IBZn) was supplemented at 10 mg Zn/kg as a direct comparison to the highest level of SAMZn. Weight gain increased (P < 0.05) with increasing Zn level, regardless of source. Weight gain of chicks fed 7 mg Zn/kg from SAMZn was not different (P > 0.05) from chicks fed 15 mg Zn/kg from ZnSO4. Weight gain was not different (P > 0.05) when comparing the 2 sources of Zn hydroxychloride supplemented at 10 mg Zn/kg. Tibia ash Zn and total tibia Zn were increased (P < 0.05) by all Zn sources and responded linearly (P < 0.05) to Zn supplementation from ZnSO4 and SAMZn. Total tibia Zn concentration was not different (P > 0.05) for chicks fed 10 mg Zn/kg from either source of Zn hydroxychloride. Multiple linear regression of total tibia Zn on supplemental Zn intake (R2 = 0.95) resulted in a RBV of 115% for SAMZn compared with ZnSO4 (set at 100%). The RBV of SAMZn was higher (P < 0.05) than ZnSO4. In conclusion, relative bioavailability of Zn (based on tibia Zn) in Zn hydroxychloride from SAMZn was higher than feed grade ZnSO4 based on multiple regression slope-ratio analysis and was similar to that of IBZn Zn hydroxychloride based on tibia Zn responses to 10 mg/kg supplemental dietary Zn.

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.