Dietary calcium requirements of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age

Background The current calcium (Ca) recommendation for broilers is primarily based on studies conducted more than 30 years ago with birds of markedly different productive potentials from those which exist today. And the response indicators in these studies are mainly growth performance and bone ash percentage. Therefore, the present study was carried out to investigate the effect of dietary Ca level on growth performance, serum parameters, bone characteristics and Ca metabolism-related gene expressions, so as to estimate dietary Ca requirements of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age. Methods A total of 420 1-day-old Arbor Acres male broilers were randomly assigned to 1 of 7 treatments with 6 replicates (10 birds per cage) and fed the corn-soybean meal diets containing 0.60, 0.70, 0.80, 0.90, 1.00, 1.10 or 1.20% Ca for 21days. Each diet contained the constant non-phytate phosphorus content of about 0.39%. Results The average daily gain decreased linearly (P < 0.001) as dietary Ca level increased. The serum and tibia alkaline phosphatase (ALP) activities, tibia bone mineral density (BMD), middle toe BMD, tibia ash percentage, tibia breaking strength, and tibia ALP protein expression level were affected (P < 0.05) by dietary Ca level, and showed significant quadratic responses (P < 0.02) to dietary Ca levels. The estimates of dietary Ca requirements were 0.80 to 1.00% based on the best fitted broken-line or quadratic models (P < 0.03) of the above serum and bone parameters, respectively. Conclusions The results from the present study indicate that the Ca requirements would be about 0.60% to obtain the best growth rate, and 1.00% to meet all of the Ca metabolisms and bone development of broilers fed a conventional corn-soybean meal diet from 1 to 21 days of age.

Regulation of bone phosphorus retention and bone development possibly by related hormones and local bone-derived regulators in broiler chicks

Background Phosphorus is essential for bone mineralization in broilers, however, the underlying mechanisms remain unclear. We aimed to investigate whether bone phosphorus retention and bone development might be regulated by related hormones and local bone-derived regulators in broilers. Methods Broilers were fed diets containing different levels of non-phytate phosphorus (NPP) 0.15%, 0.25%, 0.35%, 0.45% and 0.55% or 0.15%, 0.22%, 0.29%, 0.36% and 0.43% from 1 to 21 or 22 to 42 days of age. Serum and tibia samples were collected for determinations of bone phosphorus retention and bone development parameters, related hormones and local bone-derived regulators of broiler chickens on d 14, 28 and 42, respectively. Results Tibia ash phosphorus, total phosphorus accumulation in tibia ash (TPTA), bone mineral concentration (BMC), bone mineral density (BMD), bone breaking strength (BBS), and ash on d 14, 28 or 42, serum 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on d 28 and 42, mRNA expressions of tibia fibroblast growth factor 23 (FGF23) and dentin matrix protein 1 (DMP1) on d 14 and 28 increased linearly or quadratically (P < 0.05), while serum parathyroid hormone (PTH) on d 28, tibia alkaline phosphatase (ALP) on d 14, 28 and 42, bone gal protein (BGP) on d 14, and mRNA expression of tibia phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX) on d 14 and 28 decreased linearly or quadratically (P < 0.04) as dietary NPP level increased. TPTA, BMC, BMD, and ash on d 28 and 42, BBS on d 28, and ash phosphorus on d 42 were positively correlated (r = 0.389 to 0.486, P < 0.03) with serum 1,25(OH)2D3. All of the above parameters were positively correlated (r = 0.380 to 0.689, P < 0.05) with tibia DMP1 mRNA expression on d 14, 28 and 42, but negatively correlated (r = − 0.609 to − 0.538, P < 0.02) with serum PTH on d 28, tibia ALP on d 14, 28 and 42, and BGP on d 14. TPTA, BMC and ash on d 14 and BMD on d 28 were negatively correlated (r = − 0.397 to − 0.362, P < 0.03) with tibia PHEX mRNA expression, and BMD on d 28 was positively correlated (r = 0.384, P = 0.04) with tibia FGF23 mRNA expression. Conclusions These results suggested that bone phosphorus retention and bone development parameters had moderate to strong correlations with serum PTH and 1,25(OH)2D3 and tibia DMP1, PHEX, FGF23, ALP and BGP in broilers during the whole growth period, and thus they might be partly regulated by these related hormones and local bone-derived regulators.

Effect of 25-Hydroxycholecalciferol with Different Vitamin D3 Levels in the Hens Diet in the Rearing Period on Growth Performance, Bone Quality, Egg Production, and Eggshell Quality

A study was conducted to evaluate the effect of 25-hydroxyvitamin D3 (25-OHD) with different levels of vitamin D3 (VD3) during the rearing period (1–20 weeks) on laying hen performance, bone quality, and eggshell quality. A total of four hundred 1-day-old Lohman pullets were randomly allotted into a 2 × 2 factorial design with 2 levels of dietary VD3 (300 and 2800 IU/kg) and 2 levels of dietary 25-OHD (0 and 56 μg/kg). Each treatment had five replicates of 20 hens each. Increasing the dietary VD3 level (2800 vs. 300 IU/kg) tended to increase body weight uniformity (0.05 < p < 0.1) at 8 weeks. Dietary VD3 levels and supplementation of 25-OHD during the growing period (1–20 weeks) did not improve the laying performance and eggshell quality (eggshell strength, eggshell thickness, and eggshell relative weight) during the laying period (p > 0.05). Compared with the 300 IU/kg VD3 group, the 2800 IU/kg VD3 group showed higher serum calcium concentration and keel length at 10 weeks (p < 0.05). The addition of 25-OHD significantly increased serum calcium and 25-OHD concentration at 10 and 20 weeks and keel calcified rate at 20 weeks (p < 0.05). Increasing dietary VD3 level (2800 vs. 300 IU/kg) increased tibia ash and phosphorus content at 10 weeks, tibia strength at 72 weeks (p < 0.05), and tended to increase tibia ash content at 72 weeks, tibia calcium content and tibia strength at 20 weeks (0.05 < p < 0.1). Dietary supplementation with 25-OHD increased tibia ash content at 10 weeks, tibia calcium content and tibia strength at 20 weeks (p < 0.05), and tended to increase tibia ash content at 72 weeks (0.05 < p < 0.1). Overall, the results gathered in this study indicate that dietary supplementation of high levels of VD3 and 25-OHD during the growing period improved the tibia quality of laying hens during the early and later laying period, but had no effect on laying performance and eggshell quality during the laying period.

Effect of two phytases at two doses on performance and phytate degradation in broilers during 1–21 days of age

The effect of two microbial phytases at two dose-levels on performance and apparent ileal digestibility (AID) of nutrients in broilers fed European-type diets was studied. A total of 1,200 d-old Ross 308 male broilers were randomly assigned to 5 treatments with 30 birds/pen and 8 pens/treatment. A nutritionally adequate positive control (PC) diet was tested against 4 experimental diets containing reduced total P, retainable P, Ca and Na as per the recommended nutritional contribution for Buttiauxella phytase (Phy B) at 1,000 FTU/kg (-1.87 g/kg, -1.59 g/kg, -1.99 g/kg and -0.4 g/kg vs. PC, respectively). Experimental diets were supplemented with Phy B at 500 FTU/kg or 1,000 FTU/kg, or Citrobacter phytase (Phy C) at 1,000 FTU/kg or 2,000 FTU/kg. Diets were based on corn, soybean meal, rapeseed meal and sunflower meal and formulated by phase (starter 1–10 d, grower 11–21 d) in crumbled or pelleted form. Overall (d 1–21), at 1,000 FTU/kg, birds fed Phy C exhibited lower BWG (-2.7%), FI (-3.4%) and tibia ash (-2.2%) vs. PC (P < 0.05), and reduced BWG (-3.6%), FI (-3.9%) and tibia ash (-1.8%) vs. Phy B (P < 0.05). Phy B at 1,000 FTU/kg and Phy C at 2,000 FTU/kg maintained performance equivalent to the PC. Digestibility of Ca did not differ among phytase treatments but at 1,000 FTU/kg AID P was greater with Phy B than Phy C (72.3% vs. 62.7%, P < 0.05). Ileal phytate (myo-inositol hexakisphosphate, IP6) digestibility was greatest with Phy B at 1,000 FTU/kg which was higher than Phy C at 1,000 FTU/kg (87.6 vs. 60.6%, P < 0.05). The findings indicate a higher phytate degradation rate of Phy B than Phy C at equivalent dose-level and this is correlated to the performance of the broilers.

Evaluation of a novel hybrid 6-phytase using an updated phosphorus deficiency model in broiler chickens

One-day-old broiler chicks were used to investigate the optimal age to start feeding P-deficient diets with two non-phytate P (nPP) concentrations in exp. 1 and 7-d-old broiler chicks were used to determine P equivalency of a hybrid 6-phytase to inorganic P in monocalcium phosphate in exp. 2. In exp. 1, six treatments were prepared with 5, 6, or 7-d-old birds to start feeding P-deficient diets with 1.3 or 1.5 g kg-1 nPP. Age of birds to start feeding P-deficient diets tended to decrease (P = 0.052) mortality of birds during 14 days of feeding P-deficient diets. In exp. 2, twelve treatments including one basal diet, five diets supplied with 0.5, 0.9, 1.3, 1.7, or 2.1 g kg-1 inorganic P, and six diets supplied with 250, 500, 750, 1000, 1500, or 2000 FTU kg-1 phytase were fed to chickens from days 7 to 21 post hatching. Increasing phytase activity quadratically increased (P < 0.01) body weight gain, feed intake, and tibia ash of birds and apparent ileal digestibility and total tract retention of P. In conclusion, age of birds to start feeding PD diet affected their performance, and hybrid 6-phytase may partly replace monocalcium phosphate in P-deficient diet for broiler chickens.

Effect of two commercial limestone sources with different solubility on the efficacy of two phytases in 0-21 d old broilers

A study evaluated the effects of limestone sources with different solubility on the efficacy of two phytases in broilers. A 2×5 factorial arrangement was employed with two commercial limestone sources and five diet treatments; a positive control (PC) diet with 7.2 g/kg P and 9.6 g/kg Ca, and a negative control diet containing reductions of 1.87 g/kg available P, 1.99 g/kg Ca and 0.4 g/kg Na, supplemented with either Buttiauxella phytase (PhyB) or Escherichia coli phytase (PhyE) at 500 or 1000 FTU/kg diet. The two limestone sources were feed-grade commercial products with different particle sizes and solubility (fast-soluble (FS) 100%; slow-soluble (SS) 26% soluble after 30 minutes at pH 3) containing similar levels of Ca. Diets were fed to one-day-old Ross 308 males (n=2,400) with 30 birds/pen and eight pens/treatment in two phases (starter 0-10 d and grower 10-21 d). On d 21, ileal digesta was collected from 12 birds/pen to determine apparent ileal digestibility (AID) of P and Ca, and myo-inositol hexakisphosphate (IP6) disappearance, and tibias from four birds/pen for ash determination. The SS limestone improved body weight gain (BWG), feed intake (FI) and FCR vs FS limestone in starter/grower phases (P<0.05), and improved AID of P (P<0.05) and IP6 disappearance (P<0.05) at d 21. There was an interaction between limestone and phytase on BWG, FI and FCR in the grower phase (P≤0.05) whereby FS (vs SS) limestone reduced BWG at either dose of PhyE, but only at 500 FTU/kg of PhyB. At an equivalent dose, PhyB had higher BWG and feed intake than PhyE (P<0.05). At 1000 FTU/kg, performance was equivalent (BWG and FI) or superior (FCR) to the PC, PhyB produced greater tibia ash, AID of P and IP6 disappearance (P<0.05). The findings showed that the effects of limestone particle size on phytase efficacy varied with phytase source and dose.

Effect of Advanced Chelate Technology Based Trace Minerals on Growth Performance, Mineral Digestibility, Tibia Characteristics, and Antioxidant Status in Broiler Chickens

Background: Compared to the corresponding source of inorganic trace minerals (TM), chelated supplements arecharacterized by better physical heterogeneity and chemical stability and appear to be better absorbed in the gut due to possiblydecreased interaction with other feed components.Methods:This study was designedin broiler chickens to determine theeffects ofreplacing inorganic trace minerals (TM) with an advanced chelate technology based supplement(Bonzachicken) on growth performance, mineral digestibility, tibia bone quality, and antioxidant status. A total of 625 male 1-d-old broiler chickens were allocated to 25 pens and assigned to 5 dietary treatments in a completely randomized design.Chelated TM (CTM) supplement was compared at 3 levels to no TM(NTM) or inorganic TM. A corn–soy-based control diet was supplemented with inorganic TMat the commercially recommended levels (ITM), i.e., iron, zinc, manganese, copper, selenium, iodine, and chromium at 80, 92, 100, 16, 0.3, 1.2, and 0.1 mg/kg, respectively, and varying concentration of CTM, i.e., match to 25, 50, and 100 % of the ITM (diets CTM25, CTM50, and CTM100, respectively).Results: All diets, except diet CTM25, increased average daily gain (ADG), European performance index (EPI), and serum total antioxidant capacity compared to the NTM diet (P < 0.05). Broilers fed the CTM100 diet had lowest overall FCR and highest BWG, EPI, tibia ash, zinc, and manganese contents (P < 0.05). The tibia phosphorus content and apparent ileal digestibilities of phosphorus, zinc, and manganese were lower in the ITM group compared with the CTM50 and CTM100 groups (P < 0.05). Broiler chickens fed any of the diets exhibited higher serum glutathione peroxidase and superoxide dismutase activities and lower malondialdehyde level than those fed the NTM diet, where the best values were found for CTM100 treatment (P < 0.05).Conclusions: These results indicatethat while CTMsupplementation to 25 and 50% of the commercially recommended levels could support growth performance, a totally replacing ITM by equivalent levels of CTM could also improve growth performance, bone mineralization and antioxidant status of broiler chickens under the conditions of this study.

Early-life conditioning strategies to reduce dietary phosphorus in broilers: underlying mechanisms

Chickens adapt to P and Ca restriction during the very first days of life by improving P utilisation efficiency. The present study was built to identify the mechanisms underlying this adaptive capacity, and to identify the optimal window of application of the restriction (depletion). A total of 1600 Cobb 500TM male broilers were used. During each phase (from age 0 to 4 d, 5 to 8 d, 9 to 18 d and 19 to 33 d), the animals received either a control diet (H) or a restricted diet (L) with reduced levels of non-phytate P (nPP) and Ca (between −14 and −25 % for both) with four dietary sequences: HHHH, HLHL, LHHL and LLHL. None of the feeding strategies affected growth. Tibia ash content at day 4 and 8 was impaired when the L diet was fed from 0 to 4 and 5 to 8 d, respectively (P = 0⋅038 and P = 0⋅005). Whatever the early restriction period or length between 0 and 8 d of age, the mineralisation delay was compensated by day 18. This was accompanied by an increased mRNA expression of the Ca transporter, CALB1, and an increased apparent ileal digestibility of Ca at day 8 (P < 0⋅001). This adaptation was limited to the starter phase in restricted birds. No effect was seen on P transporters mRNA or protein expression. In conclusion, birds adapted to mineral restriction by increasing Ca and nPP utilisation efficiencies. Depletion−repletion strategies are promising in improving the sustainability of broiler production but need to be validated in phytase-supplemented diets.

The effect of enzyme and protein source on laying hens performance, eggshell and bone traits

The aim of the study was to investigate the interaction between exogenous phytase with protease and protein source in laying hens diet. A completely randomised design study with a 2 × 4 factorial arrangement was conducted to observe effects of protein source (soybean vs. yellow lupine seeds diet) and enzyme addition (no enzyme vs. phytase or protease or both) on laying hens performance, bone mineralization and some egg traits. One hundred sixty Hy-Line Brown hens at the age of 18 weeks were weighed and randomly assigned to 10 treatments, each with 16 birds. According to the producer recommendation in diets containing enzymes reduced the level of available phosphorus (50% reduction) and digestible amino acids - 5% reduction. The egg production during the entire experiment was similar in all groups without significant differences. The egg weight was also on an equal level in all treatments and it was about 58g. Birds fed different protein source were characterized by similar feed intake and feed conversion ratio during the whole experiment. The feed conversion ratio (FCR) was about 1.9-2.0 in all groups. Tibia ash was affected by enzymes supplementation. There was an interaction between protein source and enzymes addition. Birds from treatments fed with yellow lupine meal (YLM) diets reached highest tibia ash level in a group with phytase addition and in groups with SMB in a group with phytase and protease mix. The inclusion of enzymes improved the thickness of the shell. There was an interaction between protein source and enzyme inclusion. It was an interaction between experimental factors in shell breaking strength. Stronger eggshell was laid by hens from groups fed with the inclusion of yellow lupine meal. Addition of phytase had a positive impact on increasing the strength of eggshell. Only inclusion of enzymes affected significantly on shell elastic deformation in part I of eggs. Eggs from hens fed diets with inclusion of protease and phytase mix were most resistant to elastic deformation.

The effects of calcium source and concentration on performance, bone mineralisation and serum traits in male broiler chickens from 1 to 21 days of age

In total, 840 1-day-old male broiler chickens (Ross 308) were used to evaluate the effects of seven dietary calcium (Ca) concentrations (4.0, 5.5, 7.0, 8.5, 10.0, 11.5 and 13.0 g/kg, at a fixed concentration of 4.0 g/kg of non-phytate phosphorus) and two calcium sources (oyster shell and limestone) on broiler chicken Ca requirements for optimal growth rate and bone mineralisation from 1 to 21 days of age. All chickens were randomly distributed into 14 treatment groups (seven treatments of each Ca source), each being replicated four times, with 15 birds per each replicate. Results indicated that Ca source and Ca source × Ca concentration interaction had no significant (P &gt; 0.05) effects on birds average feed intake, but increasing Ca concentration to &gt;8.5 g/kg significantly deteriorated average feed intake. Average weight gain and feed conversion ratio were significantly influenced by Ca source × Ca concentration interaction, whereby high concentrations of Ca from oyster shell resulted in a poorer performance for both criteria than did those from limestone. Serum Ca, P and total protein were not affected by Ca source. However, increasing Ca concentrations had adverse effects on serum P concentration (P &lt; 0.05). Toe ash, tibia ash and phosphorus concentrations at 21 days were not influenced by Ca source, but were depressed as dietary Ca concentration increased (P &lt; 0.05). A broken-line regression analysis indicated that the Ca requirements to optimise average weight gain and tibia ash when limestone was used as a Ca source were 5.54 and 6.58 g/kg of diet respectively, and 5.80 and 6.43 g/kg of diet respectively, when oyster shell was used. In conclusion, the results indicated that Ca concentration, more than Ca source, has a significant influence on broiler chicken performance and bone mineralisation, all of which deteriorate when the dietary Ca concentration exceeds 8.5 g/kg at the constant available-phosphorus concentration of 4.0 g/kg.