Dietary Ca Concentration Research Articles

Improvement of Bioactive Components and Technological Quality of Gluten-Free Pasta with Utilization of Different Carrot Powders, Guar Gum and Pregelatinization Application

In this study, carrot (orange and black) powder substitution (0–15%) and different dough applications (guar gum (GG) addition, pregelatinization (PG) and a PG + GG combination) were researched in gluten-free pasta preparation to improve the bioactive components and technological properties. Some quality attributes and bioactive components of the pasta were determined. Black carrot powder substitution into the pasta revealed rich functional properties with higher total dietary fiber (TDF), Ca, K, Mg, P and total phenolic content (TPC) than orange carrot powder. An increased carrot powder addition ratio in the gluten-free pasta formulation resulted in enrichment in ash, mineral, β-carotene, total anthocyanin, TDF, antioxidant activity and TPC. The amounts of β-carotene and anthocyanin in the pasta samples rose to 4.42 mg/100 g and 26.08 mg CGE/100 g with the addition of 15% orange and black carrot powders, respectively. Increasing cooking loss due to high utilization ratios of carrot powder was eliminated by PG and PG + GG applications, and technologic quality was improved, especially with the PG + GG combination.

Renal expression of calcium and phosphorus transporters: contrasting responses to dietary calcium and microbial phytase in broilers and growing pigs.

Enhanced dietary Ca intake linearly increases intestinal Ca absorption in pigs, but not in broilers, suggesting potential differences in whole body Ca homeostasis. To determine the role of kidney in Ca homeostasis in these species, we varied in growing pigs in experiment (Exp) 1, the dietary Ca content 2·0 v. 9·6 g/kg and phytase 0 v. 500 FTU/kg, in broilers, in Exp 2 the dietary Ca/retainable P from 1·3 to 2·8 and phytase 0 v. 1000 FTU/kg, and in Exp 3 dietary Ca/P from 0·50 to 1·75. Increasing dietary Ca reduced renal mRNA expression of Ca-related transporters (TRPV5, TRPV6, CaBP-D28k and NCX1) and tight junctions (CLDN-12 and -16) in pigs, indicating Ca reabsorption was reduced to maintain Ca homeostasis. In broilers (Exp 2), high dietary Ca increased renal TRPV6, CaBP-D28k and CLDN-2 mRNA, indicating an increased capacity for Ca reabsorption. Moreover, the effect of dietary Ca was enhanced by inclusion of dietary phytase in pigs but reduced in broilers. Furthermore, increasing dietary Ca upregulated inorganic phosphate transporter 1 (PiT-1), while phytase downregulated xenotropic and polytropic retrovirus receptor 1 (XPR1) mRNA expression in pigs; in broilers, dietary Ca downregulated renal mRNA expression of Na-dependent phosphate transporter IIa (NaPi-IIa), PiT-1, PiT-2 and XPR1, while phytase downregulated NaPi-IIa but upregulated PiT-2 and XPR1 mRNA expression. In Exp 3, Ca/P effect on transporter mRNA expression was largely consistent with Exp 2. In conclusion of this study, together with previously measured data about Ca and P homeostasis, in pigs the kidneys play a more regulatory role in Ca homeostasis than in broilers where the intestine is more important for regulation.

359 Optimization of calcium inclusion levels in diets fed to growing and finishing beef cattle

Abstract Calcium (Ca) is a mineral that has an essential role in many biochemical pathways and functions of beef cattle. Limestone is the primary supplemental source of Ca in diets fed to growing and finishing cattle in the United States. Preliminary data indicated that inclusion of dietary Ca above the NASEM (2016) requirements as well as mean and modal concentrations reported by the most recent survey of consulting nutritionists may improve average daily gain (ADG) and feed efficiency (gain to feed ration; G:F) of finishing beef cattle. Thus, the objective of this experiment was to determine the optimal concentration of Ca in growing and finishing diets when limestone was the supplemental source of added Ca. A database was constructed containing 89 treatment means from 23 experiments published from 1963 to 2024 where dietary Ca inclusion via limestone represented treatments. Search parameters to construct the database included a combination of Ca, limestone, performance, efficiency, ADG, G:F, feedlot cattle, finishing cattle, growing cattle, and backgrounding cattle. Data were analyzed in JMP Pro 17 using a mixed model to determine linear and quadratic relationships between dietary Ca and ADG, DMI, or G:F with citation as a random effect. An economic sensitivity analysis was conducted to determine variables most influential to the dietary Ca concentration projected to minimize cost of gain using the above models. Concentration of dietary calcium was selected as the explanatory variable for the models rather than limestone because a greater proportion of variation was accounted for in the response variables prior to the citation adjustment (Ca R2 0.05 to 0.25; limestone R2 0.06 to 0.21). Diet Ca concentration and DMI were unrelated (P ≥ 0.75), but diet Ca was related to both ADG (R2 = 0.84; RMSE = 0.36; P ≤ 0.03) and G:F (R2 = 0.74; RMSE = 0.01; P < 0.01) in a quadratic fashion. Maximum ADG occurred when Ca was included at 1.20% of diet DM; approximately 2.6-fold greater than Ca requirements estimated by NASEM (2016). Cost of gain was minimized when Ca was 1.35% of diet DM. Sensitivity analysis revealed Ca concentration to minimize cost of gain was sensitive to changes in DMI, ADG, days on feed, ration cost and cost of yardage. These results provide further evidence that it may be beneficial to feed a greater amount of Ca than currently recommended by the NASEM (2016) for growing and finishing cattle. Future pen-scale feeding trials are warranted to validate the results of this meta-analysis and to determine the dose response of cattle fed graded levels of Ca. Future research should also be conducted to determine the mechanism of action responsible for the observed improvements in animal performance and efficiency resulting from feeding an increased amount of dietary Ca.

Calcium Deficiency Decreases Bone Mass without Affecting Adiposity in Ovariectomized Rats Fed a High-Fat Diet.

Obesity induced by a high-fat (HF) diet increases bone resorption and/or decreases bone formation, resulting in reduced bone mass and strength in various animal models. Studies showed that Ca intake is a modifiable factor for osteoporosis and obesity. This study investigated whether Ca deficiency affects bone structure and adiposity in ovariectomized (OVX) rats fed a HF diet. We hypothesized that Ca deficiency further decreases bone mass and increases fat mass in HF-fed OVX rats. Forty-seven OVX at 6-month-old were randomly assigned to four groups in a 2 × 2 factorial design: normal-fat (NF, 10% fat as energy) or HF (45% fat as energy) diet with either low Ca (LC, 1 g/4057 kcal) or normal Ca (NC, 6 g/4057 kcal). In addition, 12 sham-operated rats at 6 months old were fed a NFNC diet as a control for the OVX procedure. Rats were fed the respective diet for 4 months. Dietary Ca content did not affect body weight, fat mass, lean mass, food intake, energy intake, and serum cytokines. Compared to NC, LC resulted in lower tibial bone volume/total volume (BV/TV, p < 0.01), connectivity density (p < 0.01), trabecular number (Tb.N, p = 0.01), bone mineral density (BMD, p < 0.01), and femur weight (p < 0.01), femur content of Ca (p < 0.01), Cu (p = 0.03), Zn (p < 0.01), and greater trabecular separation (Tb.Sp, p < 0.01) at proximal tibia indicating bone structure deterioration. Compared to rats on the NF diet, animals fed the HF had lower BV/TV (p = 0.03) and Tb.N (p < 0.01) with greater body weight (p < 0.01), fat mass (p < 0.01), Tb.Sp (p = 0.01), the content of Ca, Cu, and Zn in the femur, and serum leptin (p < 0.01). There were no significant interactions between Ca and fat for body composition and bone structural parameters. Compared to Sham, OVX resulted in greater body weight and fat mass. The trabecular bone structure of the tibia, but not the cortical bone, was significantly impaired by the OVX procedure. These data indicate that inadequate Ca intake and a high-fat diet have independent negative effects on bone structure and that Ca deficiency does not affect adiposity in OVX rats.

Calcium and boron alone or in combination influence performances and mineral metabolism in broilers

An experiment was conducted to study the effect of dietary boron supplementation on performance and mineral metabolism in broilers fed a diet with optimal or sub-optimal levels of calcium. A total of 216 one-day old broiler chicks (Vencob) of mixed sex (mean BW 43.79±0.83 g) were distributed in completely randomized design into six treatments each with three replicates of 12 birds (6 of each sex). The six dietary treatment groups comprised of B0C0 (basal diet with normal calcium (10 g Ca/kg)), B0C1 (Basal diet of 20% calcium deficiency (8 g Ca/kg)), B0C2 (Basal diet of 40% calcium deficiency (6 g Ca/kg)), B1C0 (Basal diet with normal calcium + 25 mg/kg boron), B1C1 (Basal diet of 20% calcium deficiency + 25 mg/kg boron) and B1C2 (Basal diet of 40% calcium deficiency + 25 mg/kg boron). The performance indices like body weight (BW), weekly body weight gain, feed intake (FI) and feed conversion ratio (FCR) were recorded till 42 d of age. A metabolism trial was conducted at the end to determine the balance of minerals. Lower than the recommended level of calcium alone or with supplemental boron significantly increased the BW, feed intake, and FCR in commercial broilers at six weeks of age. Low dietary calcium significantly increased the retention of calcium, phosphorous, magnesium, iron and manganese. Dietary boron supplementation significantly increased the excreta concentration of iron and manganese. However, the absolute and relative retention of manganese and iron were unaffected when boron was supplemented into a low calcium diet; indicating the negative effect of boron on manganese, and iron metabolism can be compensated by low dietary Ca concentration.

Intestinal Calcium Absorption in Rats Is Stimulated by Dietary Lactulose and Other Resistant Sugars

Lactulose is a disaccharide analogue of lactose that is resistant to metabolism in the small intestine but not in the large intestine. The effects of lactulose and other sugars on intestinal Ca absorption were determined from the decrease in the 47Ca:47 Sc ratio between diet and feces after feeding male rats diets containing these sugars during a single night. Dietary lactulose was more potent than lactose in stimulating Ca absorption and was effective between 5 and 38 wk of age. The component sugars of lactulose, galactose and fructose, did not influence Ca absorption when provided together at concentrations equimolar to that of lactulose. The stimulation of Ca absorption by dietary lactulose increased as dietary Ca concentration was raised and was not influenced by prior injections of calcitriol. Lactulose must be present in the same meal as Ca to stimulate Ca absorption, but this stimulation was lost if the rats were fed lactulose continuously for 2 or 7 d prior to the test diet. Other sugars thought to be poorly absorbed in the small intestine (xylitol, lactobionate, arabinose, raffinose, pyroglutamate, sorbitol, gluconate and raftilose) stimulated Ca absorption to an identical extent as lactulose. Cecectomy did not influence the enhancement of Ca absorption by lactulose. These results indicate that sugars resistant to metabolism and absorption in the small intestine but not the large intestine stimulate Ca absorption in the small intestine.

Requirement of digestible calcium at different dietary concentrations of digestible phosphorus for broiler chickens 3. Broiler finishers (d 25 to 35 post-hatch)

An experiment was conducted to determine the digestible calcium (Ca) and digestible phosphorous (P) requirements of 25 to 35-day-old broiler chickens. Fifteen corn-soybean meal-based diets containing 2.0, 2.5, 3.0, 3.5, and 4.0 g/kg standardized ileal digestible (SID) Ca and 2.5, 3.5, and 4.5 g/kg SID P were fed to broilers from d 25 to 35 post-hatch. Each experimental diet was randomly allocated to 6 replicate cages (8 birds per cage). Body weight and feed intake were recorded, and the feed conversion ratio was calculated. On d 35, birds were euthanized to collect the ileal digesta, tibia, and carcass for the determination of ileal Ca, and P digestibility, concentrations of ash, Ca, and P in tibia and the retention of Ca and P in the carcass. Titanium dioxide (5.0 g/kg) was included in all diets as an indigestible indicator for the ileal digestibility measurement. Feed intake and total excreta output were measured during the last 4 d of the experimental period for the measurement of apparent total tract retention of Ca and P. Fixed effects of the experiment were dietary concentrations of SID Ca and SID P and their interaction. If the interaction or main effects were significant (P < 0.05), the parameter estimates for second-order response surface model (RSM) were determined using General Linear Model procedure of SAS. The maximum response was not predicted for most of the parameters (including growth performance and tibia) as the Ca effect was linear which indicated that the highest level of Ca employed in the study may have not been high enough. The requirement of dietary SID Ca for maximization of these parameters, therefore, depends on the dietary SID P concentration when the dietary SID Ca is within 2.0 to 4.0 g/kg. However, based on the factorial analysis, the highest weight gain was observed at 3.5 g/kg SID P and 3.5 g/kg SID Ca concentrations. Tibia ash was higher in birds fed 4.5 g/kg SID P and was unaffected by dietary SID Ca concentrations. However, based on overall findings, a combination of 3.5 g/kg SID P and 3.0-3.5 g/kg SID Ca may be recommended for the optimum tibia ash. The recommended SID Ca requirements (at 3.5 g/kg SID P) for weight gain (3.5 g/kg or 6.4 g/kg total Ca) and tibia ash (3.0-3.5 g/kg or 5.5-6.4 g/kg total Ca) are lower than the current Ca recommendations (7.8 g/kg total Ca equivalent to 4.25 g/kg SID Ca; Ross, 2019) for broiler finishers, suggesting possible excess of Ca in diets formulated based on the current recommendation.

Effect of dietary calcium concentration and exogenous phytase on inositol phosphate degradation, mineral digestibility, and gut microbiota in growing pigs.

Variations in the dietary Ca concentration may affect inositol phosphate (InsP) degradation, and thereby, P digestibility in pigs. This study assessed the effects of dietary Ca concentration and exogenous phytase on InsP degradation, nutrient digestion and retention, blood metabolites, and microbiota composition in growing pigs with ileal cannulation. In a completely randomized row-column design with four periods, eight ileal-cannulated barrows (initial body weight 27 kg) were fed four corn-soybean- and rapeseed meal-based diets containing 5.5 or 8.5 g Ca/kg dry matter (DM), with or without 1,500 FTU of an exogenous hybrid-6-phytase/kg diet. No mineral P was added and the P concentration in the feed was 4.8 g P/kg DM. Prececal InsP6 disappearance in pigs fed diets containing exogenous phytase was lower (P = 0.022) with additional Ca than without. Concentrations of InsP2-4 isomers and myo-inositol in the distal ileal digesta and prececal P digestibility were greater (P < 0.001) with exogenous phytase than without exogenous phytase. In feces, InsP6 disappearance was lower (P < 0.002) and concentration of InsP5 and InsP4 isomers was higher (P ≤ 0.031) with additional Ca compared to without additional Ca. The prececal amino acid digestibility, energy digestibility, and hindgut disappearance of energy did not differ. The Shannon diversity index of the microbiota in the distal ileal digesta and feces was similar among the diets but was lower in the distal ileal digesta than in the feces (P < 0.001). Permutation analysis of variance revealed no dietary differences between the bacterial groups within the ileal digesta and fecal samples (P > 0.05). In conclusion, additional Ca reduced the effect of exogenous phytase on prececal InsP6 degradation. Endogenous InsP degradation was impaired by additional Ca only in the hindgut but the abundance of bacterial genera in feces was not affected.

Interactive effects of calcium, vitamin D3, and exogenous phytase on phosphorus utilization in male broiler chickens from 1 to 21 days post-hatch: A meta-analysis approach

Provision of appropriate dietary phosphorus (P) content considering environmental and economic aspects has been challenging for poultry nutritionists during the last decades. For this reason, many studies have focused on factors affecting P utilization in broiler chickens, such as calcium (Ca), cholecalciferol (vitamin D3; VD), and exogenous phytase (EP), but their results have sometimes been accompanied by inconsistencies. Therefore, comprehensive knowledge of the factors affecting P utilization and their interactions is required to draw conclusions from the available results. For this purpose, a meta-analysis was conducted using 79 studies including 719 experimental treatments published between 2011 and 2021, which considered the effects of Ca, EP, and VD on P utilization in male broiler chickens from 1 to 21 days post-hatch. The collected data were fitted well to a mixed model for average daily gain (ADG; R2 = 0.941), average daily feed intake (ADFI; R2 = 0.956), feed conversion ratio (FCR; R2 = 0.989), and tibia ash (TA) content (R2 = 0.984). Linear and quadratic effects of dietary non-phytate P (NPP) content on ADG, ADFI, FCR, and TA content were observed (P < 0.001). Also, results showed the linear and quadratic effects of EP on ADG, FCR, and TA content (P < 0.001). The ADG (P < 0.01) and TA content (P < 0.05) were affected by VD supplementation. The fitted models showed that the increase in dietary Ca content linearly exacerbated all responses (P < 0.001), but such negative effects were alleviated with the increase in dietary NPP content and EP and, or VD addition due to their interactions. Results of the optimization process showed that simultaneous addition of EP and VD resulted in lower NPP concentration required to optimize growth performance and TA content compared to separate supplementation. Also, increasing dietary level of EP (up to 2000 FTU/kg of diet) reduced NPP requirement for optimal growth performance and bone mineralization. It can be concluded that Ca, EP, and VD affect the NPP requirements of broiler chickens, but the magnitude of these effects varies depending on the studied criterion.

Interactive effect of dietary levels of calcium and 25-hydroxy vitamin D3 on the performance, serum biochemical concentration and digestibility of laying hens from 61 to 70 weeks of age.

ObjectiveThe present research was conducted to evaluate the interactive effect of dietary concentration of calcium (Ca) and 25-hydroxy vitamin D3 (25OHD3) on the performance, blood composition and digestibility of laying hens.MethodsA total of 540 Hy-line brown laying hens aged 61 to 70 weeks were randomly allotted in a 3×3 factorial arrangement, consisting of three levels of 25OHD3 (0, 25, and 50 μg/kg) and three levels of Ca (3.5%, 4.0%, and 4.5%). All diets had basal concentration of 3,000 IU/kg of vitamin D3 including the 2,800 kcal/kg of metabolic energy and 16% of crude protein.ResultsThe results showed that interactive effect (p<0.05) between Ca and 25OHD3 was such that dietary 25OHD3 linearly increased interleukin-6 at all levels of Ca inclusion. Interaction (p<0.05) occurred with the highest parathyroid hormone in laying hens that received dietary concentration of Ca (3.5%) with 25OHD3 (50 μg/kg), and Ca (4.0%) with 25OHD3 (50 μg/kg). Egg production and egg weight significantly (p<0.05) increased in the 4.5% Ca group compared to the 3.5% to 4.0% Ca groups. Egg shell thickness and tibia bone length also increased (p<0.05) in groups fed a high-Ca diet (4.0% to 4.5%). Phosphorus digestibility significantly (p<0.05) increased along with dietary Ca level. Among the tested 25OHD3 groups, higher (p<0.05) egg production and tibia thickness were present in hens fed 50 μg/kg of 25OHD3. Furthermore, Ca digestibility serum Ca and 25OHD3 were significantly increased in group offered 50 μg/kg of 25OHD3.ConclusionThe results gathered in this study indicate that dietary concentrations of 4.0% to 4.5% Ca and 50 μg/kg 25OHD3 improve the performance of hens from 61 to 70 weeks of age.

The impact of dietary calcium content on phosphorus absorption and retention in growing pigs is enhanced by dietary microbial phytase supplementation.

Sixty growing male pigs were used to test the hypothesis that high dietary Ca content reduces P absorption to a greater extent in microbial phytase-supplemented diets via reducing inositol phosphate (IP) degradation and enhancing P precipitation. Pigs were equally allotted over diets with three Ca contents 2·0, 5·8 and 9·6 g/kg with or without microbial phytase (0 v. 500 FTU/kg) in a 2 × 3 factorial arrangement. Faeces and urine were collected at the end of the 21-d experimental period. Subsequently, pigs were euthanised and digesta quantitatively collected from different gastrointestinal tract (GIT) segments. Increasing dietary Ca content reduced apparent P digestibility in all GIT segments posterior to the stomach (P < 0·001), with greater effect in phytase-supplemented diets in the distal small intestine (Pinteraction = 0·007) and total tract (Pinteraction = 0·023). Nonetheless, increasing dietary Ca to 5·8 g/kg enhanced P retention, but only in phytase-supplemented diets. Ileal IP6 degradation increased with phytase (P < 0·001) but decreased with increasing dietary Ca content (P = 0·014). Proportion of IP esters in total IP (∑IP) indicated that IP6/∑IP was increased while IP4/∑IP and IP3/∑IP were reduced with increasing dietary Ca content and also with a greater impact in phytase-supplemented diets (Pinteraction = 0·025, 0·018 and 0·009, respectively). In all GIT segments, P solubility was increased with phytase (P < 0·001) and tended to be reduced with dietary Ca content (P < 0·096). Measurements in GIT segments showed that increasing dietary Ca content reduced apparent P digestibility via reducing IP degradation and enhancing P precipitation, with a greater impact in phytase-supplemented diets due to reduced IP degradation.

Influence of dietary phosphorus concentrations on the performance of rearing pigeons (Columba livia), and bone properties of squabs

The objective of this study was to investigate the effects of dietary P levels on the performance of rearing pigeons, and bone characteristics of squabs from 7 to 21 d of age. A total of 192 pairs of adult Silver King pigeons (40 wk of age) were used. The pigeons were randomly allocated to one of 4 treatment groups, each consisting of eight replicates of 6 pigeon pairs per replicate. Dietary treatments included the basal diet (containing 0.3% of P), the basal diet supplemented with 0.2, 0.4, or 0.8% inorganic P. And the dietary Ca content was kept at 1.40% across all treatments. The experimental diets were fed to parent pigeons as corn-soybean complete pellet feed, and squabs fed with crop milk secreted by parent pigeons. Pigeons in the group of 0.4% supplemental non-phytate phosphorus (NPP) had shorter (P = 0.045) oviposition interval than those in the control group and group of 0.8% NPP. When the diet was supplemented with 0.8% of NPP, the least average egg weight was observed (P = 0.006). Female breeding birds had much higher (P < 0.01) Ca, P, and ALP in serum than male ones. At 7-d of age, dietary P supplementation influenced P and Ca content in tibia ash of squabs (P < 0.05). The tibia ash Ca content in the group of 0.2% NPP was the highest among the treatments (P = 0.007). At d 21 of age, both the birds in the group of 0.4 and 0.8% NPP had higher tibia breaking strength (P < 0.01) and tibia ash contents (P < 0.001) compared to the ones in the control group. In conclusion, the P deficiency in the diet of parent pigeons could cause poor bone mineralization of squabs, especially impaired the bone-breaking strength and bone ash content. The 0.8% of NPP supplementation in the diet has a positive influence on mineralization of squabs although production depression was observed. Both P and Ca metabolism of female breeding birds were more active than male ones at earlier time points of rearing period. The desirable supplemental NPP level in diet for breeding pigeon was 0.4% according to the performance data in the present trial. The recommended Ca: P ratio for pigeons, which was different from the optimum value for broilers, needs to be studied in the future.

The Response of Layer Hen Productivity and Egg Quality to an Additional Limestone Source When Offered Diets Differing in Calcium Concentrations and the Inclusion of Phytase.

Simple SummaryDietary calcium is essential for optimal egg production and quality in laying hens, but high concentrations can impede the digestibility of other dietary components. The provision of limestone grit in addition to the main diet may help maintain overall calcium intake while allowing a reduction in dietary calcium levels. The impact of phytase, an enzyme that increases calcium availability in the gut, on the voluntary consumption of limestone grit is unknown. Here, the capacity for hens with access to a separate limestone grit source to modify Ca consumption when offered varying dietary Ca levels and phytase was evaluated. Dietary phytase reduced limestone grit consumption. Egg production was unaffected by reducing dietary calcium levels or the phytase addition. Eggshell measurements worsened in line with decreasing dietary calcium levels despite the provision of limestone grit. In summary, the provision of limestone grit resulted in comparable egg production but not eggshell quality in hens offered suboptimal levels of dietary calcium. Laying hens require substantial quantities of calcium (Ca) to maintain egg production. However, maintaining recommended dietary Ca through inclusion of limestone may impede nutrient digestibility, including that of other minerals. It was hypothesized that providing a separate source of dietary Ca in the form of limestone grit would preserve Ca intake of hens offered diets containing suboptimal Ca concentrations. Furthermore, the impact of dietary phytase at a “superdosing” inclusion rate on the voluntary consumption of limestone grit was evaluated. One hundred and forty-four laying hens (19 weeks of age) were assigned to one of six dietary treatments in a 3 × 2 factorial arrangement comprising three dietary Ca concentrations (40, 30, and 20 g/kg) and ±dietary phytase (3500 FYT/kg diet) on an ad libitum basis for six weeks. Limestone grit (3.4 ± 1.0 mm) was provided to all hens ad libitum. Hens offered diets containing phytase consumed significantly less limestone grit p = 0.024). Egg weight, rate of lay, and egg mass were unaffected by dietary treatment (p > 0.05). Egg shell weight % (p < 0.001), shell thickness (p < 0.001), and shell breaking strength (p < 0.01) decreased in line with dietary Ca levels. In summary, dietary superdosing with phytase reduced the consumption of a separate limestone source in individually housed, early lay ISA Brown hens. Egg shell quality variables but not egg production worsened in line with lower dietary Ca levels.

Phytase Supplementation Effects on Amino Acid Digestibility in Broiler Chickens are Influenced by Dietary Calcium Concentrations but not by Acid-Binding Capacity.

ABSTRACTBackgroundResponses to dietary calcium (Ca) and supplemented phytase on prececal amino acid digestibility (pcAAD) in broiler chickens vary among studies. The variation may arise from the dietary acid-binding capacity (ABC) that influences the activity of enzymes in the digestive tract and from microbial activity.ObjectiveThis study aimed to investigate whether the ABC influences phytase effects on pcAAD and whether microbial activity contributes to this.MethodsMale Ross 308 broiler chickens were provided 1 of 12 diets in 72 pens (15/pen) from day 16 of age until the end of the experiment on days 21 or 22. In a 3 × 2 × 2-factorial arrangement, the ABC was varied by replacing calcium carbonate (CaCO3) with Ca-formate or by adding formic acid to CaCO3-containing diets, and contained 5.6 or 8.2 g Ca/kg and 0 or 1500 phytase units/kg. The ileum content was collected for pcAAD measurement and microbial community composition was used to investigate whether changes in pcAAD are related to the microbiota.ResultsThree-factor ANOVA showed that reducing the ABC increased pcAAD (average 1.1 percentage points) and no significant interaction of the ABC with Ca concentration and phytase supplementation including 3-way interactions. Without phytase, increasing dietary Ca concentration decreased pcAAD (average 3.1 percentage points). Phytase supplementation increased pcAAD (average 2.1 and 5.0 percentage points at low and high Ca concentrations, respectively), to reach the same level for both Ca concentrations. Microbial functional predictions pointed towards an influence of the microbiota in the crop and ileum content on amino acid concentrations, as indicated by different relative abundances of predicted genes related to amino acid biosynthesis, degradation, and metabolism.ConclusionsDietary Ca concentrations but not the ABC modulates the effect of supplemented phytase on pcAAD in broiler chickens. The microbiota might contribute to differences in pcAAD by changing the amino acid composition of the digesta. The extent of this effect is still unknown.

Meta-analysis-based estimates of efficiency of calcium utilisation by ruminants

The most abundant mineral in the body of animals is Ca, which has crucial importance for the regulation of various processes. The maintenance of Ca balance has become more challenging, especially in lactating ruminants, owing to the increased milk yields and thus Ca requirement. To determine the Ca requirement, factors such as Ca secretion via milk or Ca deposition in body tissues and conception products are summed up to the net Ca requirement. Nevertheless, dietary Ca cannot be completely utilised by the animal to cover the net Ca requirement, therefore a value for the efficiency of Ca utilisation is applied, which is the maximum proportion of Ca from the feed that the animal can use for covering the net requirement. However, current estimates for the efficiency of Ca utilisation are inconsistent. Therefore, the objective of the present meta-analysis was to estimate the efficiency of Ca utilisation for ruminants, considering the Ca supply of the animal. A data set of 223 observations was compiled from 37 studies, including data on cattle and small ruminants. Standardised Ca digestibility was calculated from data on Ca intake and faecal Ca excretion, corrected for faecal endogenous losses. Furthermore, a data subset on only lactating ruminants was created. For this subset, Ca excretion via faeces and urine and standardised Ca digestibility were related to the Ca supply of the animal. An exponential function was fitted to standardised digestibility data in response to Ca concentration in the diet and Ca supply, revealing that standardised Ca digestibility decreased with increasing dietary Ca concentration and Ca supply. The median for standardised Ca digestibility was 40%, with a remarkable variation between 9% and 88%. In response to Ca supply, faecal Ca excretion increased in a strong linear manner (slope = 0.76, R2 = 0.96). Excretion of Ca via urine was very low even when Ca supply was very high. To conclude, Ca digestibility is a suitable indicator for the efficiency of Ca utilisation, since excessive Ca is almost completely excreted in faeces; however, Ca digestibility has to be determined at a Ca supply level below the requirement of the animal. To date, only very limited number of data have been reported for such supply conditions. Comparative studies using various Ca sources are suggested for future studies but should be conducted using a marginal Ca supply level.

Growth performance, real-time gizzard pH and calcium solubility in the gut of broiler chickens is dependent on the interaction between dietary calcium concentration and limestone particle size

ABSTRACT 1.The purpose of this study was to determine the effect of limestone particle size and dietary Ca concentration on performance, real-time gizzard pH, and Ca and P solubility in the gastrointestinal tract of 21d broiler chickens. 2. A total of 576, one-day-old Ross 308 male broilers were randomly allocated among 4 treatments, with 8 replicate pens, and 18 birds per pen. Treatments were arranged as a 2 × 2 factorial consisting of two particle sizes of limestone (coarse, CL, 1200 µm; fine, FL, 44 µm) and two Ca concentrations (9.6 or 6.0 g/kg). On d 19 and 20, four birds per treatment were administered Heidelberg pH capsules and readings monitored for 3 h. 3. Reducing Ca concentration from 9.6 to 6.0 g/kg had no effect on d 21 weight gain or FCR of birds fed CL; however, feeding FL at 9.6 g/kg Ca increased weight gain by 10% and reduced FCR by 5% compared to FL at 6.0 g/kg Ca (P < 0.001). 4. Average gizzard pH readings ranged from pH 0.67 to 3.01 across all treatments. Birds fed CL at 6.0 g/kg Ca had lower average gizzard pH compared to birds fed 9.6 g/kg Ca, while birds fed FL at 6.0 g/kg Ca had higher gizzard pH than birds fed CL at both Ca concentrations, but was comparable to birds fed FL at 9.6 g/kg Ca (P < 0.001). 5. For birds fed CL at 6.0 g/kg Ca, soluble Ca in the gizzard was approximately 40% lower (P < 0.05) than all other treatments, and reduced by 44% (P < 0.05) in the small intestine compared with birds fed FL at 6.0 g/kg Ca. 6. These findings demonstrated that the effect of Ca concentration on gizzard pH, Ca solubility and broiler performance was dependent on limestone particle size and suggested that solubility per se had little relevance to performance.

Ultrasound-treated lupin (Lupinus albus L.) flour: Protein- and fiber-rich ingredient to improve physical and textural quality of bread with a reduced glycemic index

In this study, lupin (Lupinus albus L.) flours (0, 10, 15 and 20%) debittered by ultrasound application and traditional method, and resistant starch type 4 (RS4) (0, 5 and 10%) were used in bread production to improve nutritional quality. The effect of ultrasound application on physical, textural and chemical properties of bread enriched with lupin flour and RS4 was investigated. Experiments were conducted at (2 × 4 × 3)×2 factorial design. Ultrasound application presented higher volume, specific volume and lower weight, firmness, hardness and chewiness values in bread compared to the traditional method. Besides, ultrasound had no adverse effect on chemical properties of bread. While the addition of lupin flour decreased volume and specific volume values, increased ash, fat, protein, total dietary fiber, Ca, Cu, Fe, Mg, Mn, P and Zn contents of bread. The bread prepared with 5% RS4 revealed statistically similar volume and specific volume values to bread prepared without RS4 (P > 0.05). Compared to white bread, the use of lupin flour and RS4 in bread formulation significantly (P < 0.05) decreased in vitro glycemic index. These results obtained in this study may provide useful information in the food industry to improve quality of protein- and fiber-rich bread by ultrasound application.

Fatty Acids from Different Fat Sources and Dietary Calcium Concentration Differentially Affect Fecal Soap Formation in Growing Pigs

BackgroundCalcium (Ca) can complex with free fatty acids in the gastrointestinal tract (GIT), leading to the formation of insoluble unabsorbable Ca-fatty acid soaps, contributing to the proposed effect of Ca on weight loss in humans. ObjectivesWe determined the effect of dietary Ca concentration and the individual long-chain fatty acids on Ca-fatty acid soap formation and fatty acid digestibility. MethodsNine-week-old crossbreed male pigs (n = 144; mean ± SD body weight: 21.7 ± 0.15 kg) were used as an animal model for digestion in the adult human. The animals received purified diets containing 4 Ca concentrations (0, 2, 4, and 6 g/kg diet) and 4 fat sources (tallow, palmolein oil, soybean oil, and olive oil) in a completely randomized design. Fatty acids, Ca, and Ca-fatty acid soaps were determined in feces (n = 9 per diet). ResultsIncreasing dietary Ca led to a 4-fold increase (P ≤ 0.05) in excreted palmitic and stearic acid when diets contained tallow or palmolein oil as the major fat source. More than 80% of these excreted fatty acids were present as soaps. For the tallow-based diets, increasing dietary Ca led to a decrease in stearic acid digestibility from 91% to 66% (P ≤ 0.01) and in palmitic acid digestibility from 96% to 83% (P ≤ 0.01). For the olive oil- and soybean oil-based diets dietary Ca did not (P > 0.05) influence fatty acid excretion. ConclusionsCa-fatty acid soap formation led to decreased fat absorption in the GIT of growing pigs, which supports the hypothesis that higher dietary Ca concentrations reduce fat absorption.

Cage type and mineral nutrition had independent impact on skeletal development in Lohmann LSL-Lite pullets from hatch to 16 weeks of age.

The effects of rearing cage type and dietary Ca, available P and vitamin D3 (VitD3) on body and skeletal development were studied. A total of 3,420 Lohmann LSL-Lite day-old chicks were reared in conventional (CON) or furnished cages (FUR) to 16 wk of age. Initially, 40 and 150 chicks/cage were placed in CON and FUR and transitioned to 20 and 75 chicks/cage at 8 wk of age, respectively. Three diets: Diet 1, Diet 1.5 and Diet 2 were formulated to meet nutrient specifications with Diet 1.5 and Diet 2 containing 1.5 and 2 times more Ca, P and VitD3 than Diet 1, respectively. Diets were allocated within cage type to give 6 replicates and fed in 3 feeding programs: starter, grower and developer. At 4, 12 and 16 wk of age, BW was recorded, and femur, tibia and blood samples for bone quality and related parameters. There were no interactions (P > 0.05) of cage type, diet and pullet age on BW, plasma Ca and inorganic P, femur and tibia morphometry, mineral density (MD), breaking strength (BS) and ash concentration (AC). Concentration of Ca, P and VitD3 linearly decreased BW (P < 0.001), relative femur (P = 0.010) and tibia weight (P = 0.013). A quadratic increase on femur MD (P = 0.03) and BS (P = 0.026) was observed with dietary concentration of Ca, P and VitD3. Femur (P = 0.031) was longer for CON than FUR pullets, however, femur for FUR pullets had higher (P = 0.003) AC. Cage had no effect (P ≥ 0.415) femoral MD and BS. Pullets reared in FUR cages exhibited higher tibial MD (P = 0.015), BS (P = 0.071), AC (P < 0.01) and whole-body mineral content (P < 0.01). In conclusion, cage type and diets showed independent effect on femur and tibia quality with FUR pullets exhibiting enhanced indices of mineralization. Feeding pullets twice the recommended Ca, P and VitD3 decreased BW, relative weight of leg bone but enhanced femoral strength with no effects on tibia attributes.

The effect of reducing dietary calcium in prestarter diets (0–4 D) on growth performance of broiler chickens, tibia characteristics, and calcium and phosphorus concentration in blood

During the incubation period, the Ca-to-P weight (mg/mg) ratio in the yolk increases from 0.26 on day 0 to 0.92 on day 17.5 and to 2.9 at hatch. Moreover, the absolute Ca content in the yolk increases by 41%, whereas P content decreases by 87%, from day 0 to the day of hatching. Thus, at hatch and during the first days after hatching, there are high reserves of Ca relative to P in the residual egg yolk, risking hypercalcemia and hypophosphatemia. A growth performance study was conducted to explore the effects of reducing dietary Ca content in the prestarter phase (0–4 D) on BW and bone mineral deposition during the first days after hatch and at market weight (day 37). Four prestarter (0–4 D) diets were formulated to have 0.4, 0.6, 0.8, and 1.0% Ca content. After the prestarter phase, all birds were fed with the same commercial diets based on a 3-phase feeding program (starter, grower, and finisher). Growth performance (BW, ADG, ADFI, and feed conversion ratio [FCR]) was monitored throughout the study, and blood and tibia bone samples were collected on specific days. On day 4, BW and ADG decreased with dietary Ca contents higher than 0.6% (P < 0.05), but there were no differences in BW on day 14 onward (P > 0.10). For the overall study (0–37 D), there were no differences in ADG and ADFI, but the FCR decreased with lower Ca contents (P < 0.05). On day 4, there were no differences in blood plasma Ca concentration, but P concentration increased in the group treated with diet containing 0.4% Ca compared with the groups treated with diets containing 0.6 and 0.8% Ca (P < 0.05). Tibia ash content decreased in the group treated with diet containing 0.4% Ca (P < 0.05) compared with all other treatments at the end of the prestarter phase. Tibia ash content and tibia breaking strength, on day 37, were not different among the treatments (P > 0.10). In conclusion, during the prestarter phase, BW increased with dietary Ca contents lower than 0.6%, most likely improving Ca–P balance; bone mineral deposition was reduced in this period. On feeding with a diet containing higher Ca content, bone mineral content was rapidly recovered.