Apparent Ca Research Articles

Apparent digestibility and calcium and phosphorus in urine after feeding different combinations of calcium and phosphorus sources to adult dogs.

The present study aimed to investigate the effect of the combination of a water-soluble calcium (Ca) source (CaCl2) with a water-soluble phosphorus (P) source (NaH2PO4*2H2O, diet soluble, SOL) in comparison to a water-insoluble P source (CaHPO4*2H2O, diet insoluble, INS) on apparent digestibility and renal excretion of Ca and P in dogs. The Ca intake was 226 mg/kg bodyweight (bw), the Ca/P ratio 1.9/1 in SOL and 2.0/1 in INS. The percentage of Ca from CaCl2 was 60% in SOL and 33% in INS. Eight adult Foxhound-crossbred dogs FBI, (3-5 years, bw 24-32 kg) were available. Standard digestion trials were carried out (10 days adaptation, 5 days total faecal collection). Spontaneously excreted urine was collected pre- and postprandially. In vitro water solubility of P in the mineral premixes was determined. The Ca digestibility was negative in both trials without significant differences between the groups. Apparent P digestibility was increased in group SOL (26% vs. 20% in INS). In both groups, P content in urine was higher pre- compared to postprandial, with higher concentrations in group SOL. The same was true for the P/Crea ratio. The water solubility of P in the mineral premixes used in the trials showed considerable differences: The P in premix INS was insoluble in water after 1 and after 90 min. By contrast, the P in the premix SOL was highly soluble (98%) after 1 minute. After 90 min, however, the P solubility decreased to 43%, suggesting the formation of insoluble CaP salts, presumably from CaCl2 and NaH2PO4*2H2O. In conclusion, in the present study, apparent Ca digestibility in dogs was not affected by the solubility of Ca and P, while P digestibility and renal P excretion increased.

Sampling time influences the apparent total tract digestible Ca and P equivalence of phytase in weaner pigs during a 21-day study

The objective of this study was to investigate the effect of the fecal sampling time on the apparent total tract digestibility (ATTD) of Ca and P and the efficacy of phytase in weaner pigs. During a 21-day feeding trial with 240 weaner pigs (7.4 ± 0.9 kg; 28-day old), fresh and clean fecal samples were grabbed every 2 h from 0900 to 1700 h daily from each pen on d 6–8, 13–15, or 19–21 of the trial. There were five experimental diets including a low Ca and P control diet and the control supplemented with phytase at 500, 1000, 2000, or 3000 phytase units (FYT)/kg feed. Each diet was fed to 6 pens of 8 pigs. All diets included 3 g/kg TiO2. The results showed that increasing supplementation level of phytase linearly and quadratically (P < 0.01) increased ATTD of Ca and P. There was an interaction (P < 0.01) between phytase and sampling time for ATTD of Ca and P because the response curves on d 19–21 were not parallel to those on d 6–8 and d 13–15. The ATTD of Ca in the diets supplemented with phytase was higher (P < 0.05) at the sampling time of d 19–21 of the trial than at other sampling times, which contrasts with unaffected ATTD of Ca in the control diet over the sampling times. In control diet, the ATTD of P was higher (P < 0.05) at the sampling time of d 13–15 of the trial compared to d 19–21; but in the diets supplemented with 2000 or 3000 FYT/kg phytase, the ATTD of P was higher (P < 0.05) at the sampling times of d 13–15 and d 19–21 of the trial than at d 6–8. There was no interaction between phytase and sampling time on the release of digestible P by phytase, but the interaction showed a tendency for digestible Ca release (P = 0.07). The concentration of digestible Ca and P released by phytase increased linearly (P < 0.01) with sampling time. In conclusion, the phytase efficacy in terms of digestible Ca and P release increased with time in this feeding trial with weaners pigs. Therefore, we suggest that the fecal samples should be grabbed at the midpoint of a feeding trial to measure the phytase efficacy in weaner pigs.

Secondary fluorescence effect quantification of EPMA analyses of olivine grains embedded in basaltic glass

Trace element analysis of olivine is challenging but vital, since trace elements in olivine can potentially record crystallization conditions and, correspondingly, conditions of magma generation, evolution, and transport dynamics. Electron microprobe analysis (EPMA) is one of the most widely used methods for trace element analysis in olivine for many reasons including but not limited to high-spatial resolution and high precision. EPMA protocols with high-beam currents and long-counting times provide accurate trace element concentrations with low-detection limits. However, these protocols neglect the effect of secondary fluorescence (SF) across phase boundaries, which may lead to fictitious analytical results when analyses are performed near other phases. In these cases, obtaining accurate EPMA data requires correction of SF effects from the adjacent or surrounding phase. In this study, the contents of olivine trace elements Ca, Ni, Mn, Ti, Cr, and Al have been measured in run products of experimental high-temperature studies on mafic magmatic systems consisting of olivine grains embedded in basaltic glass. Olivine grain fragments with known composition, were embedded in basaltic powder, and heated to 1250 °C in 1-atm vertical gas-mixing furnace for a few minutes and quenched. EPMA analyses of the olivine grains before and after the experiments were used to quantify the effect of SF, which was found to be most significant for Ca and Ti, and to a lesser extend for Al, and to depend on the distance from the interface, olivine grain geometry, accelerating voltage, and olivine and glass compositions. By combining our experimental results with systematic SF calculations performed with the Monte Carlo simulation program PENEPMA, analytical expressions that give the apparent Ca, Ti, and Al concentrations due to SF in equant olivine grains embedded in basaltic glass were derived. These equations, which allow for a rapid correction of SF effects, are used to assess the average overestimation due to SF of olivine analyses included in current experimental databases, which might be the source of major discrepancies observed in petrological tools utilizing trace element contents in olivine.

Mineral composition of serially slaughtered Holstein steers supplemented with zilpaterol hydrochloride.

Calf-fed Holstein steers (n = 115; 449 ± 20 kg) were utilized in a serial harvest experiment. A baseline group of five steers was harvested after 226 d on feed (DOF), which was designated day 0. The remaining cattle were assigned randomly to 11 harvest groups, with slaughter every 28 d. Cattle were either not (CON) or were fed zilpaterol hydrochloride for 20 d followed by a 3 d withdrawal (ZH). There were five steers per treatment in each slaughter group ranging from days 28 to 308. Whole carcasses were divided into lean, bone, internal cavity, hide, and fat trim components. Apparent mineral retention (Ca, P, Mg, K, and S) within the body was calculated as the difference between mineral concentration at slaughter and day 0. Mineral concentration at day 0 was determined from body composition of steers harvested at day 0 multiplied by individual live body weight (BW) at day 0. All data were analyzed as a 2 × 11 factorial arrangement with individual animal as the experimental unit. Orthogonal contrasts were used to analyze linear and quadratic contrasts over time (11 slaughter dates). There were no differences in concentration of Ca, P, and Mg in bone tissue as feeding duration increased (P ≥ 0.89); concentration of K, Mg, and S in lean tissue did fluctuate across DOF (P < 0.01). Averaged across treatment and DOF, 99% of Ca, 92% of P, 78% of Mg, and 23% of S present in the body were in bone tissue; 67% of K and 49% of S were in lean tissue. Expressed as gram per day, apparent retention of all minerals decreased linearly across DOF (P < 0.01). Expressed relative to empty body weight (EBW) gain, apparent Ca, P, and K retention decreased linearly as BW increased (P < 0.01) whereas Mg and S increased linearly (P < 0.01). Apparent retention of Ca was greater for CON cattle (greater bone fraction) and apparent retention of K was greater for ZH cattle (greater muscle fraction) when expressed relative to EBW gain (P ≤ 0.02), demonstrating the increase in lean gain by ZH cattle. There were no differences in apparent retention of Ca, P, Mg, K, or S due to treatment (P ≥ 0.14) or time (P ≥ 0.11) when expressed relative to protein gain. Apparent retention averaged 14.4 g Ca, 7.5 g P, 0.45 g Mg, 1.3 g K, and 1.0 g S/100 g protein gain. Expressing apparent mineral retention on a protein gain basis minimized effects of rate and type of gain, allowing for better comparison across treatments and time. Feeding zilpaterol hydrochloride did not affect apparent mineral retention when expressed relative to protein gain.

Low-calcium diets increase duodenal mRNA expression of calcium and phosphorus transporters and claudins but compromise growth performance irrespective of microbial phytase inclusion in broilers

The hypothesis that dietary inclusion of microbial phytase improves apparent calcium (Ca) digestibility thereby allowing a lower dietary Ca inclusion without compromising growth performance was tested. One-day-old male Ross 308 broilers (25 birds/pen, 9 pens/treatment) were assigned to 8 experimental diets containing one of 4 dietary Ca to retainable P (rP) ratios (1.3, 1.8, 2.3, and 2.8) with (1,000 FTU/kg) or without microbial phytase. On d 21 to 23, digesta from different intestinal segments of 8 birds per pen were collected to determine apparent Ca and P digestibility. Mid duodenal mucosa was collected for expression of Ca (CaBP-D28k, PMCA1) and P (NaPi-IIb, PiT-1, PiT-2, and XPR1) transporters by RT-qPCR. Dietary phytase inclusion in low Ca/rP diets increased Ca digestibility in the distal ileum (Pinteraction = 0.023) but not the proximal or distal jejunum. Broilers receiving the lowest Ca/rP displayed the lowest body weight gain, highest feed conversion ratio (P < 0.001), and lowest tibia strength, irrespective of dietary phytase inclusion. Incremental dietary Ca/rP linearly reduced P digestibility to a greater extent in the absence of phytase in the distal jejunum and ileum (Pinteraction = 0.021 and 0.001, respectively). Incremental dietary Ca/rP linearly reduced serum P more in phytase-free diets (Pinteraction < 0.001), and lowered duodenal expression of P transporters NaPi-IIb, PiT-2, and XPR1 (P = 0.052, 0.071 and 0.028, respectively). Incremental dietary Ca/rP linearly increased (P < 0.001) serum Ca irrespective of phytase inclusion, accompanied by a lower (P < 0.001) duodenal expression of Ca transporters CaSR, CaBP-D28k and PMCA1 and Ca-pore forming claudins CLDN-2 and CLDN-12. Dietary phytase increased (P = 0.026) NaPi-IIb but reduced (P = 0.029) CLDN-2 expression. Incremental Ca/rP reduced Ca and P digestibility, increased serum Ca, lowered serum P and inhibited mRNA levels of Ca and P-related transporters, indicating that these transporters and CLDN contribute to the observed effect of dietary Ca and phytase on Ca and P absorption. Despite the improvement in Ca digestibility, dietary phytase did not restore the compromised growth performance and tibia strength of broilers fed a Ca-deficient diet, leading to rejection of the hypothesis.

Shake loss intensities in x-ray photoelectron spectroscopy: Theory, experiment, and atomic composition accuracy for MgO and related compounds

The relative intensities of XPS core levels, scaled by their photoionization cross sections, are regularly used to determine sample atomic composition. Cross sections, however, give the intensity to all possible final states for the core ionizations, not just to the main peak. This includes all intrinsic satellite structure (shake states and, for open shell systems, the different ionic multiplets). In practice, for solids, this is usually experimentally impossible to determine accurately because such a satellite structure sits on the inelastically scattered electron background and cannot be easily separated. Therefore, usually, only the intensity of the main peak is used. This limits the ultimate possible accuracy of XPS composition determination. The purpose of the present paper is to examine the contributions that a theoretical analysis of losses of intensity can make to improve quantitation. For an MgO single crystal, we show that the correct stoichiometry of 1:1 can be recovered using the theoretical analysis of the experimental MgO peak ratio intensities. For materials with a sufficient bandgap for the XPS main peaks to be separated from the scattered background, the intensity of main peaks can often be accurately determined. Thus, if one uses theory to calculate that fraction of the total intensity lost from a main peak into all its satellite structure, the intensity of just main peaks could then be used to more accurately determine relative atom % composition. This work tests this approach using a single crystal MgO (50% Mg, 50% O) standard. Ab initio electronic structure theory of representative MgO clusters is used to determine Hartree–Fock wave functions for the ground state and final ionized states corresponding to the main Mg 2p and O1s XPS peaks of the oxide. The sudden approximation, SA, is used to determine the fractional losses from these main peaks to shake satellites, which is found to be greater for O1s than Mg2p. This results in predicted “apparent composition” for stoichiometric MgO of 55.2% Mg, 44.8% O instead of the true 50% Mg, 50% O. Equivalent theory for CaO results in a predicted apparent Ca value of 53.4%. Experimentally, using Mg2s or 2p intensity ratio to O1s, we find values between 52.2% and 56.0% Mg using two crystals and four different instrument electron pass energies. The average value of the measurements is 54.5% Mg when corrected for the presence of an adventitious carbon overlayer and slight surface hydroxide. Though this agreement with theory may be somewhat fortuitous, given the potential experimental errors, which are fully discussed, it is similar to that in our earlier study on LiF. We also present preliminary experimental data on Mg(OH)2 and MgSO4, which show a similar trend of apparently higher than 50% Mg, but we have no theory values. We are not yet able to experimentally test for validation of the difference between apparent composition for MgO (55.2% Mg) and CaO (53.4% Ca), owing to significant carbonate formation at the surface of the single crystal CaO. An important conclusion is that the theoretical determination of shake losses, obtained with ab initio wavefunctions and the SA, is likely to be a useful way to calibrate the accuracy and reliability of compositions obtained from XPS intensities and merits further study.

Comparison of the apparent ileal calcium digestibility of limestone in broilers and layers

ABSTRACT 1. The apparent ileal calcium (Ca) digestibility coefficients of two limestone sources in growing broilers and layers were determined in two separate experiments. 2. In each experiment, two maize-based diets were developed with two limestone sources (A, experiment 1 and B, experiment 2) to contain either 8.0 g/kg Ca for broilers or 40 g/kg Ca for layers. The two sources differed in particle size, with limestone A being finer and limestone B being coarser. Each experimental diet was randomly allotted to six replicate cages and offered for 3 days from 19 to 21-day post-hatch to broilers and during 40 weeks of age to layers. The total tract Ca retention was also measured using the indicator ratios in the diet and excreta. 3. In both experiments, the apparent ileal Ca digestibility, gizzard pH and gizzard Ca concentration were higher (P < 0.05) in layers than in broilers. The apparent ileal digestibility coefficient of limestone A for broilers and layers was 0.50 and 0.62, respectively. The corresponding values for limestone B were 0.43 and 0.70, respectively. The apparent total tract retention of Ca was similar (P > 0.05) between broilers and layers in both experiments, and between the two sources. 4. The data show that the layers are more efficient in absorbing Ca from limestone than broilers.

No Observed Adverse Effects on Health Were Detected in Adult Beagle Dogs When Fed a High-Calcium Diet for 40 Weeks.

Simple SummaryCalcium (Ca) is an essential mineral that plays a vital role in many bodily functions. There is evidence that high levels of dietary Ca for puppies and growing dogs can result in adverse growth and health effects, with certain breeds and dog size categories being most susceptible, for example, large breed sizes or beagles. Until recently, little was known about the health consequences of high Ca diets to adult dog, however, a study in the large sized breed Labrador retriever found no adverse health consequences when feeding diets containing levels of Ca near maximum levels set by pet food regulators (2.5 g per 100 g dry matter) for 40 weeks. This current study fed a similar high Ca diet to adult beagles, a medium sized breed for 40 weeks and monitored the dogs’ health using an extensive suite of health parameters. All dogs remained healthy and did not display any clinically relevant signs of adverse health relating to diet at any point during or following completion of the study.The implications of long-term high calcium (Ca) intake are well documented in growing dogs and in adult dogs of large breed size, however, the consequences on other breeds and breed sizes are yet to be determined. Eighteen neutered adult beagles, nine males and nine females aged 1.4–4.4 years, were randomized to control or test diets providing in g∙4184 kJ−1 (1000 kcal−1): 1.44 and 7.19 total Ca balanced with 1.05 and 4.25 total phosphorus, respectively, for 40 weeks. Health parameters, ultrasound scans, radiographs, glomerular filtration rate, and mineral balance were measured at eight-week intervals. All dogs remained healthy with no measured evidence of orthopedic, urinary, or renal disease. The test diet resulted in a 5.2 fold increase in fecal Ca excretion. Apparent Ca digestibility (%) and Ca balance (g/d) did not significantly (p > 0.05) change from baseline in the test diet group, although dogs displayed a positive Ca balance (maximum at week 8, 1.11 g/d with 95% CI (0.41, 1.80)) before a neutral Ca balance was restored at week 32. Despite an initial positive Ca balance, we can conclude that no measurable adverse health effects were observed as a result of the test diet fed in this study in beagles over a period of 40 weeks.

Effects of dietary cation-anion differences at the early stage of transitional period on dry matter intake and plasma Ca metabolism in beef cows

The present study investigated the effects of dietary cation-anion differences (DCADs) on dry matter intake (DMI), nutrient digestibility, body condition score (BCS), body fat, plasma ion metabolism, and relative hormone levels through a perinatal feeding experiment. Eighteen healthy Simmental crossbred cows (Simmental ♂ × native Yunnan Yellow ♀; body weight, 325.4 ± 27.63 kg) were allocated to one of three treatment groups with six replicates each. The control (CON) group received basal diet without anionic salt supplementation, with a DCAD of 127.56 mEq kg−1 DM. The T2% and T4% groups received basal diet supplemented with 2% and 4% anionic salts, with DCADs of −1.60 and −129.10 mEq kg−1 DM, respectively. All groups received isoenergetic and isonitrogenous diets. Blood samples were collected on prepartum days 7 and 3; on the day of calving; and on postpartum days 1, 3, 7, 14, and 42. Prenatal urine pH decreased with decreasing DCAD (P < 0.001). Compared with that in the CON group, DMI in the T2% and T4% groups was decreased by respectively 11.4 % and 17.8 % (P = 0.005) at the early stages of perinatal period (−21 to 0 days), but DMI in the T2% group was increased by 9.4 % (P < 0.046) at the later stages of perinatal period (0–21 days). The postpartum BCS in the T2% and T4% groups was 25 % lower than that in the CON group (P = 0.038). Prepartum apparent P digestibility was increased in the T2% and T4% groups (P = 0.017) and prepartum apparent Ca digestibility was increased in the T2% group (P = 0.022). The content of colostrum fat, Ca, lactose, and immunoglobulin G was increased in the T2% group (P < 0.05). On postpartum day 1, the plasma ionized (i) Ca concentrations were increased by 20.4 % and 19.4 % (P < 0.05), the plasma 1,25(OH)2D3 concentrations were increased by 15.6 % and 12.7 % (P < 0.05), and the plasma iK concentrations were decreased by 8.8 % and 9.8 % (P = 0.003) in the T2% and T4% groups, respectively, compared with values in the CON group. In addition, the iMg, iP, and parathyroid hormone levels in the T2% group were increased (P < 0.05). On prepartum day 7, the plasma glucose concentration in the T2% group was higher than that in the CON group (P = 0.010), and on the day of calving, the plasma glucose concentration in the T4% group was higher than that in the T2% group (P = 0.041). On postpartum day 1, the plasma non-esterified fatty acid (NEFA) concentration in the T2% group was lower than that in the CON group (P = 0.021), but there was no significant difference in this concentration between the T4% and CON groups (P > 0.05). The postpartum plasma β-hydroxybutyric acid (BHB) concentrations in the T2% and T4% groups were lower than those in the CON group (P < 0.001). On postpartum day 42, progesterone levels in the T2% and T4% groups were respectively 27.3 % and 16.7 % lower than those in the CON group (P < 0.001). Therefore, the addition of anionic salts to reduce DCAD accelerated the recovery of postpartum DMI, decreased plasma NEFA and BHB concentrations, and increased plasma iCa concentration. Under the present experimental conditions, 2% anionic salt supplementation was more appropriate.

Dietary inclusion of AZOMITE improves feed efficiency in broilers and egg production in laying and broiler breeder hens

The dietary inclusion of aluminosilicates has been reported to enhance pellet quality, improve feed mill throughput, bind toxins, improve feed efficiency, and promote immunological function across a variety of production systems. AZOMITE is a product marketed as a hydrated sodium calcium aluminosilicate containing macro and trace minerals, and rare earth elements and the potential benefits of its dietary inclusion in broiler, layer, and broiler breeder diets was investigated. In a battery study, broilers were fed diets containing 0, 0.125, 0.250, or 0.500% AZOMITE from 0 to 21 d of age. Laying hens were fed a control diet or this diet supplemented with 0.25% AZOMITE from 54 through 98 wk of age, with the hens fed a standard molting diet or this diet supplemented with 0.25% AZOMITE from 71 to 72 wk of age. Broiler breeder hens were fed a control diet or this diet supplemented with 0.25% AZOMITE from the onset of photostimulation at 21 wk of age through 65 wk of age. All 3 dietary inclusion rates of AZOMITE improved (P < 0.05) the feed to body weight gain ratio in broilers fed these diets relative to broilers fed the control diet. In laying hens total marketable eggs, and in broiler breeder hens total settable eggs were increased (P < 0.05) with the dietary inclusion of AZOMITE by 8 eggs per hen. The inclusion of dietary AZOMITE also improved apparent Ca and P digestibility in broilers and tibia ash content in laying hens. The results indicate the dietary inclusion of AZOMITE in poultry diets improves bird performance.

The partial replacement of sodium chloride with sodium bicarbonate or sodium sulfate in laying hen diets improved laying performance, and eggshell quality and ultrastructure

This study investigated the effects of dietary chloride (Cl) reduction on laying performance and eggshell quality by substitution of sodium bicarbonate (NaHCO3) or sodium sulfate (Na2SO4) for part of dietary sodium chloride (NaCl), and further explored its mechanism for improving eggshell quality. A total of 360 29-wk-old Hy-line Brown laying hens were randomly allocated to 5 dietary treatments, including a basal diet contained 0.33% NaCl (control group, 0.27% dietary Cl), and 4 experimental diets that contained 0.21% and 0.15% dietary Cl by substituting Na2SO4 or NaHCO3 for part of NaCl in the basal diet. No significant differences were observed in blood Na+, Cl−, K+ and Ca2+ levels and pH value as well as serum creatinine and uric acid contents among 5 treatments (P > 0.05). Dietary Cl reduction increased egg production and ADFI during wk 33 to 36, 37 to 40 and 29 to 40 of age and decreased feed conversion ratio during wk 37 to 40 of age (P < 0.05). The hens fed with diets containing 0.15% Cl increased eggshell breaking strength, thickness and weight ratio in wk 40 of age (P < 0.05). Birds fed with dietary 0.21% and 0.15% Cl exhibited higher effective layer thickness and lower mammillary layer thickness of eggshell than those fed with dietary 0.27% Cl (P < 0.05). Apparent Ca metabolizability of hens was increased with dietary Cl reduction (P < 0.05). Total Ca of eggshell of dietary 0.15% Cl group was higher than that of dietary 0.27% Cl group (P < 0.05). No significant differences in laying performance, eggshell quality and Ca metabolism of layers were observed between Na2SO4 and NaHCO3 replacement groups (P > 0.05). Overall, dietary Cl reductions could improve laying performance and eggshell quality by substitution of NaHCO3 or Na2SO4 for part of NaCl, and there were no differences in the improvements between these two substitutes. The improved eggshell quality may be attributed to improved eggshell ultrastructure and increased supply of eggshell Ca2CO3.

Nonlinear consolidation model for the prediction of constant pressure expression of semi-solid materials

Nonlinear model of constant pressure expression is proposed for semi-solid materials and filter cakes. In this model the compressive pressure PS is replaced by the special power-law pressure function θ=1+PSPa1-nconsidering constitutive equation for the specific cake resistance α=α01+PSPan, where α0, Pa and n are the constants. The linearized form of obtained equation has analytical solution, which is similar to the solution of classical Terzaghi equation, but in terms of the proposed power-law pressure functionθ. Consequently, pressure profiles and local characteristics of compressed semi-solid materials can be better described. Constitutive relations for the compressibility modulus G and consolidation coefficient C are presented as power-law functions of the compressive pressure PS and used for the approximative analytical and numerous solutions of the obtained nonlinear consolidation equation. Consolidation coefficient (filtration diffusivity) of highly compressible filter cakes can vary little with compressive pressure increase or even remain constant due to the concurrency between G and α, which are both rise with higher compressive pressure PS.Several examples of the application of proposed model are presented for different moderately and highly compressible filter cakes (H.K. kaolin, CaCO3, silica, activated sludge, water treatment (WT) plant residue). The profiles of local compressive pressure PS and local cake characteristics (specific cake resistanceα and solidosity εS) are simulated and compared for different filter cakes based on the analytical and numerical solutions of this model. The values of apparent consolidation coefficient Ca are simulated based on the adjustment of numerical and analytical solutions of the proposed model. These values can be used for better prediction of solid–liquid expression behavior.

Coarse limestone does not alleviate the negative effect of a low Ca/P ratio diet on characteristics of tibia strength and growth performance in broilers

The hypothesis was tested that an increased digestion of coarse compared with fine limestone can alleviate the negative effects of a low dietary Ca/P ratio on the growth performance and characteristics of tibia strength (CTS) in broilers. A total of 1,152 Ross 308 broiler chickens received a standard commercial starter feed from day 0 to 13. From day 14 onward, birds received 1 of 12 diets containing 1 of 6 Ca/P ratios (0.50, 0.75, 1.00, 1.25, 1.50, and 1.75) and 1 of 2 limestone particle sizes (<500 [fine] and 500 to 2,000 [coarse] μm) in a study with a 6 × 2 factorial arrangement of treatments. Total P content was fixed at 5.5 g/kg for all treatment diets. Each treatment was replicated 6 times with 16 birds per replicate pen. On day 20 and 21, twelve birds per pen were randomly selected from 4 of the 6 replicate pens for tibia analysis and digesta collection from different gut segments. The apparent Ca digestibility was higher for fine than coarse limestone in the jejunum (P = 0.043). However, this difference in Ca digestibility disappeared for the low, whereas it remained for the high Ca/P ratios in the proximal (Pinteraction = 0.067) and distal (Pinteraction = 0.052) ileum. In addition, coarse limestone improved apparent P digestibility in the proximal and distal ileum (P < 0.001) but not in the jejunum (P = 0.305). Regardless of limestone particle size, reducing dietary Ca/P ratio linearly improved apparent Ca and P digestibility in the proximal and distal ileum (P < 0.001). Moreover, decreasing dietary Ca/P ratio linearly (P < 0.001) and quadratically (P < 0.046) reduced the CTS. Reducing dietary Ca/P ratio linearly (P < 0.003) and quadratically (P ≤ 0.006) decreased body weight gain and increased feed conversion ratio. For both fine and coarse limestone, the optimal Ca/P ratio was 1.00 to 1.25 to optimize apparent Ca and P digestibility while maintaining growth performance and CTS. Reducing Ca/P ratio from 1.75 to 1.00 improved distal ileal Ca and P apparent digestibility from 36.6 to 53.7% and 48.0 to 58.3%, respectively. In conclusion, coarse limestone is equally digestible with fine limestone at a low Ca/P ratio but is less digestible at a high Ca/P ratio, and the optimal Ca/P ratio in the diet is 1.00 to 1.25 for both fine and coarse limestone.

Effect of age and dietary crude protein content on the apparent ileal calcium digestibility of limestone in broiler chickens

The objective of the present study was to investigate the effects of age on the apparent ileal calcium (Ca) digestibility of limestone for broiler chickens. Six treatment groups of different ages, namely days 1–7, 8–14, 15–21, 22–28, 29–35 and 36–42, were utilised. A maize-based diet (crude protein, 79 g/kg) containing limestone as the sole Ca source and, supplying 9.0 g/kg Ca, was fed to six replicate cages of broilers during each of the six periods. The birds were fed a commercial broiler starter diet until the introduction of the assay diet, except the day 1–7 age group. Ileal digesta were collected on day 7 (twelve birds per cage), 14 (ten birds per cage), 21 (eight birds per cage), 28 (six birds per cage), 35 (six birds per cage) or 42 (six birds per cage). A secondary objective was to examine the influence of dietary protein content on Ca digestibility. An additional diet containing a crude protein content of 153 g/kg was developed and fed to six replicate cages (eight birds per cage) from day 15 to 21 post-hatch. The birds in the age group of 15–21 days and fed the 79 g/kg crude protein diet served as the control treatment. Titanium dioxide (5 g/kg) was included in all diets as an indigestible marker for apparent ileal digestibility measurements. Total tract Ca retention, pH of gizzard digesta and relative weights of gizzard and gizzard digesta were also measured. Apparent ileal Ca digestibility coefficients declined linearly (P < 0.001) with advancing age, from 0.51 at day 7 to 0.27 at day 42. Ca retention coefficients declined quadratically (P < 0.01) with advancing age, from 0.56 at day 7 to 0.30 at day 28 and then plateaued. Age quadratically (P < 0.01) affected the gizzard pH where the pH declined from day 7 to 21 and then increased. Relative weights of gizzard and gizzard digesta were quadratically decreased (P < 0.001) with advancing age. Increasing the dietary protein content had no effect (P > 0.05) on the apparent ileal digestibility and retention of Ca. Increasing dietary protein had no effect (P > 0.05) on the relative weights of gizzard and gizzard digesta. In conclusion, the present results showed that the Ca digestibility of limestone in broilers, fed a maize-based diet with limestone supplying 9 g/kg Ca, declined with advancing age.

Increasing calcium from deficient to adequate concentration in diets for gestating sows decreases digestibility of phosphorus and reduces serum concentration of a bone resorption biomarker.

The objective of this experiment was to test the hypothesis that the concentration of Ca in diets fed to late gestating sows affects the apparent total tract digestibility (ATTD) and retention of Ca and P, serum concentrations of Ca and P, hormones, and blood biomarkers for bone formation and resorption. Thirty-six sows (average parity = 2.8) were housed in metabolism crates from day 91 to day 104 of gestation and fed 1 of 4 experimental diets containing 25, 50, 75, or 100% of the requirement for Ca. All diets met the requirement for P. The initial 5 d of each period were the adaptation period, which was followed by 4 d of quantitative collection of feces and urine. At the end of the collection period, a blood sample was collected from all sows. Results indicated that feed intake, weights of dried fecal and urine samples, and the ATTD of DM were not affected by dietary Ca, but ATTD of Ca increased (quadratic, P < 0.05) as Ca in diets increased. Urine Ca output was not affected by dietary Ca, but Ca retention increased (quadratic, P < 0.05) as Ca intake increased. Fecal P output increased (linear, P < 0.001) as dietary Ca increased, which resulted in a linear decrease (P < 0.001) in the ATTD of P. Urine P output also decreased (linear, P < 0.001) as dietary Ca increased, but P retention increased (linear, P < 0.05). Regressing the apparent total tract digestible Ca against dietary Ca intake resulted in a regression line with a slope of 0.33, indicating that true total tract digestibility of Ca in calcium carbonate was 33%. Serum concentrations of Ca and P and estrogen, calcitonin, and parathyroid hormone were not affected by dietary Ca. Serum concentration of carboxyterminal cross-linked telopeptide of type I collagen (CTX-I) decreased (linear, P < 0.05) as dietary Ca increased, which is a result of reduced bone resorption as dietary Ca increased. Serum bone-specific alkaline phosphatase tended to decrease (linear, P < 0.10) as Ca in diets increased, but the concentration of osteocalcin (OC) in serum was not affected by dietary Ca. The ratio between OC and CTX-I tended to increase (P < 0.10) as dietary Ca increased, which indicated that there was more bone formation than resorption in sows as dietary Ca increased. In conclusion, P digestibility in late gestating sows decreased, but retention of P increased, as dietary Ca increased from inadequate to adequate levels and blood biomarkers for bone resorption changed as Ca and P retention increased.

Studies on the measurement of ileal calcium digestibility of calcium sources in broiler chickens

Results from 3 experiments relating to the measurement of ileal calcium (Ca) digestibility in 4 different Ca sources for broiler chickens are presented herein. The first experiment was conducted to determine the effect of basal diet composition on the true Ca digestibility of limestone, meat and bone meal (MBM), monocalcium phosphate (MCP), and dicalcium phosphate (DCP). Eight experimental diets were developed based on 2 basal diets (corn-based or corn starch-based) with each of the 4 Ca sources. Two Ca-free diets representing both basal diets were used to determine the endogenous Ca losses. Each diet was randomly allotted to 6 replicate cages (6 birds per cage) and fed from 21 to 24 D post-hatch. Calcium digestibility of corn-based diet was higher (P < 0.05) than the corn starch-based purified diet. The average true Ca digestibility coefficients of limestone, MBM, MCP, and DCP were determined to be 0.51, 0.41, 0.43, and 0.32, respectively. The second experiment was conducted to examine the effect of indicator type on the apparent Ca digestibility of limestone. Two experimental diets with either titanium dioxide or acid insoluble ash (Celite) were developed. Each diet was randomly allotted to 6 replicate cages (8 birds per cage) and fed from 21 to 24 D post-hatch. Total tract Ca retention was also measured using the indicator ratios. Indicator type had no influence (P > 0.05) on the digestibility measurements. Ca retention determined using acid insoluble ash was higher (P < 0.05) compared to that determined using titanium dioxide. The third experiment was conducted to determine the effect of dietary adaptation length on apparent Ca digestibility of limestone. The experimental diet was offered from day 21 to 6 replicates (6 birds per cage) each for 24, 72, 120, or 168h and the ileal digesta were collected. Calcium digestibility at 24h was higher (P < 0.05), and increasing the adaptation length from 72 to 120h had no effect (P > 0.05) on the digestibility.

Long-term effects of Buttiauxella sp. phytase on performance, eggshell quality, apparent ileal Ca and P digestibility, and bone properties of white egg layers

Adequate dietary Ca and available phosphorus (avP) are essential to long-term egg production and bone health in laying hens. The effects of dietary Ca and avP levels and Buttiauxella sp. phytase (BSP) were studied in Lohmann LSL Lite hens from 30 to 70 wk of age (woa). Hens (n = 456; 4 per cage) were fed either a primary breeder recommendation-based diet (positive control; PC); the PC with avP and Ca levels reduced by 0.146 and 0.134% of the diet, respectively, without (NC) or with 300 FTU/kg BSP (NC+BSP). Egg production, BW, feed intake, FCR, and eggshell quality from 30 to 70 woa, and apparent ileal digestibility of P (AIDP) and Ca (AIDCa), and bone quality at 32, 48, and 70 woa were measured. The avP and Ca levels in the NC diet were not clinically deficient, as most parameters were unaffected by diet. Hen BW from 34 to 70 woa tended to be 2.9% greater (P = 0.076) for PC and NC+BSP compared to NC. Mid-diaphysis cortical bone mineral content (CBMC) tended to be 10% and 9% higher (P = 0.065) in the NC+BSP hens than in NC hens at 48 and 70 woa, respectively. AIDP of NC+BSP was 24% greater (P = 0.034) than of NC at 32 woa and tended to be 18% greater (P = 0.082) than AIDP of PC at 48 woa, and 25% lower than of NC and PC at 70 woa (P = 0.028). AIDCa was 25% lower for NC+BSP than PC at 48 woa only (P = 0.037). The avP and Ca sufficiency in the NC diet limited the opportunity to determine a phytase effect. Although the supplemental BSP tended to increase BW and 48 and 70 woa CBMC, and increased 32 woa AIDP, the efficacy of BSP could not be determined due to the lack of an NC effect on most parameters. Commercial laying hens can maintain health and productivity at lower than recommended levels of dietary Ca and avP; phytase supplementation may allow for even further reductions.

Са2+-мобілізація у гладеньких міоцитах сечового міхура щура у відповідь на прикладання капсаїцину

According to the previous studies of the heat-activated TRPV1 ion channel, in the organism it could play not only the canonical role of the nociceptive temperature sensor (activation threshold &gt;42 °С) but also be a polymodal receptor involved in numerous other processes due to the permeability of its selective pore for Ca 2+ ions. Prior studies conducted by other research groups provided indirect evidence obtained with immunochemistry and PCR approaches suggesting the presence of this ion channel in the smooth muscle cells (BSM) of the urinary bladder though the functional data is still absent. In this study we investigated the effect of capsaicin (CAP), a pungent component of hot chili pepper and an agonist of TRPV1, on the transmembrane currents and the Ca 2+ signaling of the bladder smooth muscle cells of the rat. CAP at the saturating concentration of 10 μM had no influence on the transmembrane currents of BSMs registered with the whole-cell patch clamp technique which suggests the absence of TRPV1 in the plasma membrane of these cells. Along with this negative data the control electrophysiological recordings on the dorsal root ganglion (DRG) neurons was conducted showing the presence of CAPS-evoked currents in this cells. On the opposite, the application of this pharmacological agent induced the apparent Ca 2+ response in calcium imaging experiments with the Ca 2+ -sensitive fluorescent dye Fluo-4 AM in 42 % of the BSMs examined. At the same time, the rest of these cells showed no calcium influx though their viability was validated with control cholinoreceptor agonist, carbachol (CCh), in the concentration of 100 μM. Therefore, our findings suggest the previously unreported expression of TRPV1 in the part of the BSMs and its subcellular localization in the sarcoplasmic reticulum of these cells.

Exploring circumstellar effects on the lithium and calcium abundances in massive Galactic O-rich AGB stars

Context. We previously explored the circumstellar effects on Rb and Zr abundances in a sample (21) of massive Galactic O-rich asymptotic giant branch (AGB) stars. Here we are interested in clarifying the role of the extended atmosphere in the case of Li and Ca. Li is an important indicator of hot bottom burning while the total Ca abundances in these stars could be affected by neutron captures. Aims. We report new Li and Ca abundances in a larger sample (30) of massive Galactic O-rich AGB stars by using more-realistic extended model atmospheres. Li abundances had previously studied with hydrostatic models, while the Ca abundances have been determined here for the first time. Methods. We used a modified version of the spectral synthesis code Turbospectrum and consider the presence of a gaseous circumstellar envelope and radial wind in the modelling of the spectra of these massive AGB stars. The Li and Ca abundances were obtained from the 6708 Å Li I and 6463 Å Ca I resonance lines, respectively. In addition, we studied the sensitivity of the pseudo-dynamical models to variations of the stellar and wind parameters. Results. The Li abundances derived with the pseudo-dynamical models are very similar to those obtained from hydrostatic models (the average difference is 0.18 dex, σ2 = 0.02), with no difference for Ca. This indicates that the Li and Ca content in these stars is only slightly affected by the presence of a circumstellar envelope. We also found that the Li I and Ca I line profiles are not very sensitive to variations of the model wind parameters. Conclusions. The new Li abundances confirm the Li-rich (and super Li-rich, in some cases) nature of the sample stars, supporting the activation of hot bottom burning in massive Galactic AGB stars. This is in good agreement with the theoretical predictions for solar metallicity AGB models from ATON, Monash, and NuGrid/MESA but is at odds with the FRUITY database, which predicts no hot bottom burning leading to the production of Li. Most (20) sample stars display nearly solar (within the estimated errors and considering possible non-local thermodynamic equilibrium effects) Ca abundances that are consistent with the available s-process nucleosynthesis models for solar metallicity massive AGB stars, which predict overproduction of 46Ca relatively to the other Ca isotope and the creation of the radioactive isotope 41Ca (half life of 0.1 Myr) but no change in the total Ca abundance. A minority (five) of the sample stars seem to show a significant Ca depletion (by up to 1.0 dex). Possible explanations are offered to explain their apparent and unexpected Ca depletion.

Effect of fructo-oligosaccharide supplementation in soya beverage on the intestinal absorption of calcium and iron in newly weaned rats.

Studies have shown the positive effects of prebiotics on the intestinal absorption of Ca and Fe. The present study evaluated the effect of fructo-oligosaccharide (FOS) supplementation in soya beverage (SB) on absorption mechanisms of Ca and Fe in recently weaned rats. Male Wistar rats were divided into four groups: lactose-free cows' milk (CM), lactose-free CM with FOS (0·8 g/100 ml) (CMF), SB and soya beverage with FOS (0·8 g/100 ml) (SBF). These rats were euthanised after 1 week of treatment. Organ weight, pH of the caecal content and absorption mechanisms of Ca and Fe were evaluated. The results showed that the weight of the caecal contents increased in the CMF and SBF groups, and the pH of the caecal contents was lower in these groups. The Hb levels of the CMF and SB groups were higher when compared with that of the CM group and lower in relation to the SBF group. The apparent Ca and Fe absorption and apparent Ca retention in the CM group were higher when compared with the SB group, whereas in the CMF group, they were higher in relation to the SBF group. Divalent metal transporter 1 (DMT1) protein expression in the duodenum was higher in the SBF group than in the SB and CMF groups. SB resulted in lower intestinal Ca absorption and higher Hb concentration, despite the lower apparent Fe absorption in relation to CM. Supplementation with FOS provided beneficial effects on Hb and DMT1 protein expression in the duodenum, in addition to improving the absorption process.