Dietary Ca Level Research Articles

Effect of Phytase on the Sodium Requirement of Starting Broilers 1. Sodium Bicarbonate as Primary Sodium Source

Recent work has indicated that phytase enzymes may influence Sodium (Na) metabolism in the chick but to date no work has conclusively demonstrated that the Na requirement of the chick for live performance is influenced by phytase supplementation. In this study male broilers were fed diets with Na levels ranging from 0.10-0.28% using sodium bicarbonate as the primary source of supplemental Na. Diets were supplemented with no phytase, 500 FTU/kg (1x) or 2,000 FTU/kg (4x) of phytase. When phytase was added the dietary Ca and Nonphytate P (NPP) were adjusted in accordance with anticipated release of these minerals. For 1x phytase the Ca and NPP were reduced 0.10% each and for 4x phytase were reduced by 0.20% each. The combination of seven Na levels and three phytase treatments resulted in 21 dietary treatments, each of which was fed to six replicate pens of five male chicks housed in electrically heated battery brooders with wire floors. Experimental diets and tap water were provided for ad libitum consumption from day of hatch to 18 d. At 16 d of age excreta from each pen was collected and freeze dried to determine moisture content and the excreta analyzed to determine amounts of Ca, P and Na. There were no significant differences in Body Weight (BW), Feed Conversion (FCR), Feed Intake (FI), fecal moisture (FH2O), or mortality of broilers fed diets with different levels of phytase indicating that the dietary adjustment in NPP and Ca levels for the addition of the phytase did not adversely affect performance of the birds. The dietary Na leve l significantly affected BW, FCR, FI or FH2O. There were no significant interactions of dietary Na and level of phytase supplementation. Regression analysis showed an overall estimate of 0.18±0.01% Na for BW and 0.19±0.01% Na for FCR. There was little indication that the Na requirement was affected by phytase. The level of phytase and Na in the diet had significant effects on excreta levels of P, Ca and Na. The use of lower dietary levels of NPP and Ca in association with the addition of the phytase resulted in significant reduction in excreta levels of these minerals, but had no significant effect on levels of excreted Na. Increasing the dietary Na level significantly affected the levels of all three minerals in the excreta. Although the dietary Na level had significant effects on both excreta P and Ca, these followed no consistent trends with no significant difference in Ca or P excretion between chicks fed diets with the lowest and highest Na levels. There were significant interactions between dietary Na levels and levels of phytase supplementation for all three minerals in the excreta. However, these did not appear to follow any consistent pattern. While it is apparent that phytase influences the metabolism of Na within the body, the data from the present study suggests that this has little impact on the dietary need for Na.

Effects of dietary calcium levels and limestone particicle size on the performance, tibia and blood of laying hens

A total of 405 23-week-old ISA® Brown layers were distributed in a completely randomized experimental design in a factorial arrangement with nine treatments consisting of three dietary calcium levels (3.5, 3.75, and 4.5%) and three limestone particle sizes (100% fine limestone (FL), 70% FL + 30% coarse limestone (CL) and 50% (FL) + 50% (CL)), with nine replicates of five birds per cage. The following parameters were evaluated: percentage of lay, defective eggs, egg weight, egg mass, feed intake, feed conversion ratio (per kg eggs and per dozen eggs), and mortality. Dietary Ca levels significantly affected lay, with birds fed diets containing 4.5% calcium producing less eggs as compared to those fed 3.0 and 3.75% Ca. Egg production linearly decreased as dietary Ca levels increased, but blood Ca levels (mg/L) increased in 28-week-old birds. The interaction of dietary Ca levels and limestone particle sizes resulted in a reduction in tibial ash Ca content as dietary Ca levels increased and as fine limestone was replaced by coarse limestone. It is concluded that a dietary Ca level of 3.75% and 100% fine particle limestone are required to maintain adequate egg production and available Ca blood level.

Phytase supplementation improved growth performance and bone characteristics in broilers fed varying levels of dietary calcium

An experiment was conducted to investigate the effect of dietary Ca level on the efficacy of phytase. A total of 288 male Ross × Ross 708 broilers with initial and final BW of 37 and 705 g, respectively, were used in brooder batteries from 0 to 21 d posthatch. Each treatment had 8 replications with 6 broilers/replicate pen. All diets were corn-soybean meal based and formulated to contain 1.26% total Lys. The treatments were positive control with 0.45% nonphytate P and 1% Ca and a negative control with 0.20% nonphytate P with 0.67, 1.00, or 1.33% Ca fed with or without 500 phytase units of Optiphos (Escherichia coli-derived phytase; JBS United Inc., Sheridan, IN). Increasing Ca from 0.67 to 1.33% linearly decreased (P ≤ 0.003) ADG, ADFI, bone breaking strength, bone weight, tibia ash weight, and percentage tibia ash; however, quadratic effects were found for ADFI, G:F, percentage tibia ash, and mortality (P ≤ 0.09). Phytase supplementation increased (P < 0.001) ADG, ADFI, bone breaking strength, bone weight, ash weight, and percentage tibia ash and decreased (P = 0.054) mortality. The increase in ADG, ADFI, bone weight, ash weight, and percentage tibia ash (P ≤ 0.026) and decrease in mortality (phytase × Ca linear; P = 0.058) from phytase supplementation was greater in broilers fed the higher levels of Ca. Calcium utilization was linearly decreased (P < 0.002) with increasing Ca. Phosphorus digestibility and utilization were increased with increasing levels of Ca (P ≤ 0.002); however, P utilization decreased at 1% Ca and increased at 1.33% (quadratic; P < 0.070). Phytase supplementation increased Ca utilization (P < 0.024), P digestibility (P < 0.001), and P utilization (P < 0.029). However, the increase in P digestibility (phytase × Ca; P < 0.021) was greater at the lower levels of Ca whereas P utilization (phytase × Ca; P < 0.001) was greater at 1.33% Ca with phytase supplementation. The results of this research indicate that dietary Ca level, within the ranges used in this experiment, does not negatively affect the efficacy of phytase.

Effects of prepartum dietary calcium level on calcium and magnesium metabolism in periparturient dairy cows

The aim of this study was to investigate the effects of dietary Ca level (4.9, 9.3, and 13.6 g/kg of DM) on Ca and Mg homeostasis in dairy cows around parturition. Cows of the Swedish Red breed (n = 29) with no previous veterinary treatment for milk fever were divided into 3 groups, and each group was fed one of the different diets during the last 15 to 32 d of gestation. Calcium was added as ground limestone, and the Mg concentration was 1.8 g/kg of DM in all diets. After calving the cows were fed similar diets. Plasma was sampled twice per week until calving, and 6, 12, and 24 h, 2, 4, and 7 d after calving. Spot urine samples were collected twice weekly until calving and creatinine was used as a marker of daily urinary excretion. Fecal samples were collected 2 times per day for 5 d starting 2 wk before expected calving, and acid-insoluble ash was used as an indigestible marker to estimate digestibility. Apparent digestibility of Mg and daily Mg excretion in the urine were lower in the dry period for cows fed the highest Ca level. Plasma Mg concentration was lower on 2, 4, and 7 d after calving in cows fed the highest level of Ca. Treatment groups did not differ in plasma Ca concentration, parathyroid hormone concentration, or bone mobilization, evaluated using crosslinked carboxyterminal telopeptides of type I collagen (CTx) as a marker. Plasma Ca concentration decreased and plasma CTx concentration increased 6 h after calving. The apparent digestibility of Ca during the dry period was not affected by dietary Ca, but the cows fed 4.9 g Ca/kg of DM excreted 1.2 g of Ca/d in the urine, which was higher compared with 0.4 g/d and 0.6 g/d for the cows fed 9.3 g of Ca/kg of DM and 13.6 g of Ca/kg of DM, respectively. The results show that feeding 13.6 g of dietary Ca/kg of DM impaired the Mg absorption during the dry period, and resulted in decreased plasma Mg concentration after calving, but prepartum dietary Ca level did not affect plasma Ca, parathyroid hormone, or CTx concentrations.

Effects of a Low Calcium Diet and Oxalate Intake on Calcium Deposits in Soft Tissues and Bone Metabolism in Ovariectomized Rats

It is controversial whether low calcium intake, commonly associated with osteoporosis, results in calcium accumulation in soft tissues. This study was conducted to investigate the effects of low calcium (Ca) and oxalate (ox) intake on soft-tissue Ca deposits and bone metabolism in ovariectomized (ovx) rats. Eight week old female Sprague-Dawley rats were ovariectomized and divided into four groups. The rats were fed experimental diets containing low (0.1%, w/w) or normal (0.5%, w/w) Ca with or without sodium oxalate (1%, w/w); Sham/NCa, Ovx/NCa, Ovx/LCa, Ovx/NCa-ox, Ovx/LCa-ox for 6 weeks. All ovx rats showed a remarkable increase in body and tissue weight, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, blood urea nitrogen, alkaline phosphatase, and decreases in weight, ash, and Ca contents, as well as bone breaking force compared to those in sham rats. Serum Ca concentration was not significantly affected by dietary Ca levels or ox intake. Kidney Ca, ox acid content, and microscopic Ca deposition increased remarkably in the Ovx/LCa-ox group compared to those in the other groups. Ca content in the spleen and aorta also increased significantly, but the weight contents, Ca, bone breaking force, and Ca and oxalic acid in feces decreased significantly in the Ovx/LCa-ox group. Serum parathyroid hormone levels were not significantly different among the groups. These results indicate that low Ca intake decreased bone mineral content and increased Ca deposits in soft tissues, which was aggravated by ox intake in ovx rats. Thus, high ox intake may result in a kidney disorder in patients with osteoporosis who eat a low Ca diet.

Effect of dietary mineral level and inulin inclusion on phosphorus, calcium and nitrogen utilisation, intestinal microflora and bone development

An experiment was conducted to investigate the interaction between dietary phosphorus (P) level (4 vs 6 g total P kg(-1)) and inulin inclusion (0 vs 20 g kg(-1)) on coefficients of total tract apparent digestibility, nitrogen (N), P and calcium (Ca) utilisation, bone mineralisation, selected gastrointestinal microflora, intestinal volatile fatty acid concentrations and digesta pH in the ileum, caecum and proximal colon. Owing to the design of the experiment, as dietary P level increased, there was also an increase in dietary Ca level in order to maintain a sustainable dietary Ca/P ratio. Entire male finisher pigs (n = 10 per treatment) with a similar initial body weight (51 kg, standard deviation 2.4 kg) were used. Inulin inclusion lowered (P < 0.01) Enterobacteriaceae populations in the proximal colon compared with pigs offered diets without added inulin. However, intestinal bacterial populations of Lactobacillus and Bifidobacterium spp. were unaffected. Inulin inclusion had no effect on mineral digestibility or bone mineralisation. Pigs offered low P and Ca diets had lower (P < 0.01) bone mineralisation than pigs offered high P and Ca diets. Intestinal bacterial populations of Enterobacteriaceae in the proximal colon were lowered by inulin inclusion. Inulin inclusion did not affect P, Ca or N utilisation or bone mineralisation in the finisher pig when offered either a low or a high P diet. Increasing the P and Ca content of the diet led to an increase in bone mineralisation.

Laying performance and eggshell quality in laying hens fed diets supplemented with prebiotics and organic acids

The aim of the study was to evaluate the effect of organic acids and the prebiotic fructans on egg production and eggshell quality when added to the layer diet with different levels of calcium and phosphorus. The experiment was carried out on 168 Bovans Brown hens, allocated to 14 groups of 12 replications. Each hen (replication) was kept in an individual cage 40 cm &amp;times; 40 cm in size. A 2 &amp;times; 7 factorial arrangement, with two dietary levels of calcium and phosphorus (normal &amp;ndash; 3.70% Ca, 0.65% P, and reduced &amp;ndash; 3.25% Ca, 0.60% P) and with diets supplemented by selected additives (none, 0.75% inulin, 0.75% oligofructose, 0.50% volatile fatty acids (VFA), 0.25% medium chain fatty acid (MCFA), 0.30% VFA + 0.20% MCFA, 0.75% inulin + 0.50% VFA) was used. The experiment was carried out over 34 weeks, from the age of 26 to 70 weeks. There were no statistically confirmed effects of the factors studied in this experiment on egg performance, i.e. laying rate, egg mass, feed intake and feed conversion. Reducing the dietary levels of Ca and P significantly decreased eggshell percent, thickness, density and breaking strength. The additives used had a considerable effect on eggshell quality at 46, 58 and 70 weeks of age, and these positive effects were most pronounced in the case of inulin and MCFA. There was no significant interaction between Ca and P dietary levels and the additives used. It was thus concluded that selected feed additives which lower the pH of the diet and intestinal content can beneficially influence eggshell quality in older high-producing laying hens. &amp;nbsp;

Phosphorus digestibility is highly influenced by phytase but slightly by calcium in growing pigs

Phytases are added to pig diets to render phytate phosphorus (P) available and improve P utilization. However, the efficacy of phytase may be influenced by dietary calcium (Ca). This experiment studied the interaction between phytase addition and dietary Ca. A wheat, barley and soybean meal diet without inorganic phosphate was used. Plant phytase was 650 FTU/kg DM in the not heat-treated diet. A 3 * 2 factorial design was used to evaluate the response of growing pigs to 3 levels of dietary Ca, 4, 6, 8 g Ca/kg as fed, and 2 levels of phytase, 0 and 750 FTU/kg. Ca was supplied as CaCO 3. Eight litters of 6 female pigs (40 kg) were kept in metabolism crates and fed one of the 6 diets for 12 d: 5 d for adaptation and 7 d for total collection of faeces and urine. No significant interaction between phytase and Ca was seen but phytase addition significantly increased P digestibility (from 38 to 58%) whereas the P digestibility was not significantly affected by Ca. In contrast, P retention and utilization was significantly affected by the interaction (p ≤ 0.001). When no phytase was added, P retention was 38% of P intake independent of Ca level. When phytase was added, P utilization increased from 42 to 55 and 57% when Ca was 4, 6 and 8 g/kg feed. This indicates that the pigs' Ca need was not met at 4 g/kg feed. Urinary and faecal P was affected by the phytase and Ca interaction.

Dietary calcium affects neonatal bone development

Effects of dietary calcium (Ca) deficiency on skeletal integrity and endocrine parameters are well characterized in growing and mature mammals; however, little work has examined Ca nutrition during the neonatal period. In this study, we examined the effects of neonatal Ca nutrition on bone integrity, endocrine parameters, and in vivo mesenchymal stem cell (MSC) activity. Neonatal pigs (24 ± 6h post‐partum) were pair‐fed either a Ca adequate or a 30% Ca deficient liquid formula diet for 18 days. There were no differences in growth rate or feed conversion efficiency based on dietary Ca level and all pigs grew at a rate similar to sow‐reared pigs. As anticipated, dietary Ca deficiency reduced (P &lt; 0.05) both BMD and bone flexural strength. The anticipated increase (P &lt; 0.05) in plasma PTH levels in pigs fed the Ca deficeint diet was not evident until the end of the study. Surprisingly, dietary Ca level did not affect plasma Ca or 1,25(OH) 2 vitamin D concentrations throughout the study. Calcium deficiency reduced (P &lt; 0.05) the in vivo proliferation of MSC isolated from bone marrow by approximately 50%. These results indicate that neonatal Ca nutrition is crucial for bone integrity and suggest that early life Ca restriction may have long‐term effects on bone integrity via its effects on MSC activity.

Cross-calibration of 45calcium kinetics against dynamic histomorphometry in a rat model to determine bone turnover

Techniques for assessing bone dynamic are in high demand. Calcium (Ca) kinetic studies are currently being used in our clinical studies of bone turnover in adolescents and elderly. The technique has rarely been compared to the standard method of bone dynamic histomorphometry. We perturbed bone turnover through ovariectomy and sub-optimal dietary Ca in a female rat model to cross-calibrate Ca kinetics against dynamic histomorphometry. Kinetic studies involved oral and intravenous administration of 45Ca and monitoring the tracer in blood, urine, feces, and bone over a 3-day period as part of a metabolic Ca balance study. Histomorphometric indices of mineral apposition rate, mineralizing surface, and bone formation rate were obtained from proximal metaphysis and mid-diaphysis region of tibial bone. Bone mineralization and resorption rates at the whole skeletal level as evaluated by kinetic studies were significantly correlated with the volume-based bone formation rate (BFR/BV) evaluated by dynamic histomorphometry in metaphyseal trabecular bone (r=0.72 and r=0.61, respectively, p<0.001) and surface-based bone formation rate (BFR/BS) in tibial cortex (r=0.63, p<0.001 and r=0.59, p<0.01, respectively). Significant correlations were also demonstrated between bone resorption and mineralization rates at the whole skeletal level (r=0.91, p<0.001) using 45Ca kinetic data. Ca kinetic modeling showed an increase (p<0.001) in skeletal resorption and formation rates in response to ovariectomy (27.6 vs. 13.8mg/d for bone resorption and 42.7 vs. 28mg/d for bone formation in ovariectomized vs. their Sham-operated control animals, respectively). Ca kinetic data also showed that bone formation decreased by 30% and whole bone balance by 50%, when dietary Ca level was reduced from 0.4% to 0.2% (34.2 vs. 23.8mg/d and 10.4 vs. 5.1mg/d, respectively, p<0.001). Our data suggest that Ca kinetic studies can be used reliably to rapidly detect changes in bone turnover at the whole skeletal level in response to interventions.

Effect of Organic Acids and Prebiotics on Bone Quality in Laying Hens Fed Diets with Two Levels of Calcium and Phosphorus

In an experiment conducted on caged Bovans Brown hens, the effect of diet supplementation using organic acids and prebiotic fructans on the biomechanical and geometrical indicators of the tibia and femur bones was evaluated. At 25 weeks of age, layers were randomly assigned to 14 experimental groups, each comprising 6 hens kept in individual cages. A 2 x 7 factorial arrangement, with two dietary levels of calcium and phosphorus (normal - 37.0 g Ca/kg, 6.5 g P/kg, and reduced - 32.5 g Ca/kg, 6.0 g P/kg), and with diets supplemented by selected additives (none; inulin, 7.5 g/kg; oligofructose, 7.5 g/kg; short chain fatty acids (SCFA), 5.0 g/kg; medium chain fatty acid (MCFA), 2.5 g/kg; SCFA, 3.0 g/kg + MCFA, 2.0 g/kg; inulin, 3.0 g/kg + SCFA, 5.0 g/kg) was used. The experiment was conducted for 45 weeks and concluded when the hens were 70 weeks old. At 70 weeks of age, reducing the dietary levels of Ca and P had decreased the bone breaking strength by 8.9% (P &amp;#x2AAC 0.001) and the yielding load by 5.6% (P &amp;#x2AAC 0.05). A similar tendency for bone breaking strength (P &amp;#x2AAC 0.05) and stiffness (P &amp;#x2AAC 0.05) was found in the femur bones. The diet with a lower level of Ca and P negatively affected the geometrical indicators of the bones such as cortex thickness (P &amp;#x2AAC 0.05) and cross section area (P &amp;#x2AAC 0.05), but had no effect on bone weight and length. Hens fed diets supplemented with oligofructose, MCFA, SCFA + MCFA or inulin + SCFA displayed a significantly higher bone breaking strength and yield load in the tibia bone than that of the control group. In the case of femurs, a positive influence of MCFA or simultaneous addition of inulin + SCFA on bone breaking strength was found. The additives had no significant effects on the geometrical indicators of either bone. It was concluded that selected feed additives which lower the pH of the diet and intestinal content can beneficially affect the biomechanical indicators of the bones of high-productive laying hens.

Inclusão de ácidos graxos de cadeia curta em diferentes níveis de cálcio na dieta de frangos de corte

Noventa e seis frangos de corte, machos, de linhagem Cobb e de 21 aos 31 dias de idade foram alimentados com a inclusão de ácidos graxos de cadeia curta (AGCC) e diferentes níveis de cálcio. Foram determinados o balanço de cálcio (Ca) e de fósforo (P), a metabolizabilidade da matéria seca (MetMS), matéria orgânica (MetMO) e matéria mineral, da energia bruta e proteína bruta da dieta, a porcentagem de cinzas nas tíbias (%CzT), além do desempenho das aves. Utilizou-se um esquema fatorial 5x4 (sem ácido orgânico; ácido fórmico, ácido acético, ácido propiônico e ácido butírico) x (0,40, 0,59, 0,78 e 0,97% de Ca), com um delineamento completamente casualizado. O acréscimo de Ca na dieta afetou de forma positiva e quadrática o balanço de Ca e P, sendo os melhores níves estimados em 0,87 e 0,75% de Ca dietético, respectivamente, e afetou positiva e linearmente a MetMS e a MetMO, bem como a %CzT. Houve redução na eficiência de retenção do Ca, de forma quadrática, com o aumento do nível de cálcio. Os AGCC não apresentam efeitos detectáveis sobre as respostas estudadas e nem interação com os níveis dietéticos de Ca utilizados. A melhor exigência estimada de Ca dietético, considerando o balanço de cálcio, foi de 0,87%.

Effects of Dietary Calcium Levels on Growth-performance and Digestive Function in Cattle Fed a High-fat Finishing Diet

Plascencia, A., Alvarez, E.G., Montañto, M., Salinas-Chavira, J. and Zinn, R.A. 2009. Effects of dietary calcium levels on growth-performance and digestive function in cattle fed a high-fat finishing diet. J. Appl. Anim. Res., 36: 179–184. A growth performance and digestion trial was conducted to evaluate the influence of dietary calcium level on the feeding value of a high-fat (11%) finishing diet. Treatments consisted of three levels of dietary Ca: 0.50, 0.70 and 0.90% (DM basis). Ca source was limestone and yellow grease was included as supplemental fat. There were no treatment effects (P>0.20) on DMI. Increasing dietary Ca level enhanced ADG (P<0.10) and feed conversion (F:G, P<0.05). There were both linear (P<0.05) and quadratic (P<0.10) effects on dietary NE. Increasing Ca level from 0.7 to 0.9% increased dietary NEg by 8.0%,. Carcass dressing percentage and LM area increased (P<0.10) with increasing dietary Ca level. There were no treatment effects (P>0.10) on total tract digestion of OM, ADF, lipid, starch or N. However, increasing Ca level from 0.7 to 0.9% decreased ruminal digestion of OM (P<0.05), ADF (P<0.10) and feed N (P<0.05), but enhanced (P<0.10) ruminal microbial efficiency and (P<0.01) ruminal N efficiency. Postruminal Cci disappearance tended to be greater (P<0.10) with 0.9% dietary Ca. Increasing dietary calcium level did not affect (P>0.20) either ruminal pH or ruminal soluble Ca. It is concluded that dietary Ca levels greater than 0.7% (DMB) are necessary to achieve optimal performance of feedlot steers fed a high-fat finishing diet.

Influence of calcium and phosphorus feeding on markers of bone metabolism in transition cows

A study was carried out to verify the effect of Ca and P levels on production, digestibility, and serum bone metabolism biomarkers in dairy cows. Fifty-two nonlactating multiparous cows (≥3 lactations) were confined in a free-stall barn approximately 20 d before calving. A standard close-up diet was fed to cows once daily until d 2 postpartum. Cows were randomly assigned to 1 of 4 dietary treatments arranged in a 2×2 factorial approach averaging 0.64% Ca for high Ca (HCa), 0.46% Ca for low Ca (LCa), 0.47% P for high P (HP), and 0.38% P for low P (LP) on a dry matter basis. Experimental diets were fed twice daily from 3 d in milk (DIM) until 31 DIM. Intake and milk yield were recorded daily. Milk samples were collected on d 28, 29, and 30 postpartum for components analyses. Blood samples were drawn 10 d before expected calving, at calving, and at 15 and 30 DIM for serum analyses of osteocalcin, a biomarker of bone accretion, and pyridinoline, a biomarker of bone resorption. Total fecal collection was conducted when cows in a block averaged 20 DIM. Intake and production traits were not significantly affected by any of the dietary treatments. Cows averaged nearly 21 kg/d dry matter intake and 44 kg/d milk yield from 6 to 31 DIM. There were no significant differences across treatments in body weight or body condition score loss. Phosphorus intake, P fecal output, P digestibility, and P apparent absorption were affected by dietary P content. Calcium intake was higher with HCa, but Ca fecal output, digestibility, and apparent absorption showed an interaction between dietary Ca and dietary P. Calcium fecal output was 100.6 g/d for cows fed HCaHP, intermediate for cows on the HCaLP diet (89 g/d), and similar among cows fed the 2 LCa diets (70 g/d with LCaHP and 75 with LCaLP). There was no significant effect of Ca or P on osteocalcin measurements. Pyridinoline concentrations were affected by dietary Ca levels and tended to have a significant dietary Ca×dietary P interaction. Phosphorus apparent digestibility occurred independently of dietary Ca levels. Results of this study suggest that more bone was mobilized in cows fed LCa diets, but excess dietary P caused greater and prolonged bone mobilization regardless of dietary Ca content.

The importance of dietary calcium consumption in two species of semi-terrestrial grapsoid crabs

Calcium (Ca) is essential for crustaceans, due to calcium carbonate (CaCO3) deposition in the new exoskeleton to harden it. The purpose of this work was to study short term Ca balance in terms of dietary Ca ingestion in two phylogenetically related crabs (Superfamily Grapsoidea) showing different degrees of terrestrial adaptations: Sesarma rectum Randall, 1840 and Neohelice granulata (Dana, 1851). Dietary Ca ingestion was studied using purified diets with different Ca concentrations (0, 2.2 and 6.66 % Ca), together with measurements of Ca excretion and Ca hemolymph levels. The results showed that both crabs had the same response to foods containing different levels of Ca, with both species eating more of the high Ca diet. However, S. rectum consumed more per mg body mass at all Ca concentrations (6 mg.g-1 for S. rectum against 3 mg.g-1 for N. granulata). Both species excreted/egested Ca differently: S. rectum excreted Ca proportionally to ingestion, whereas N. granulata maintained constant faecal Ca output at all dietary Ca levels. Moreover, Ca hemolymph levels for crabs fed the different diets were independent of dietary Ca. In conclusion, both S. rectum and N. granulata seem to regulate the consumption of diets containing more Ca, which suggests a fine balance for Ca intake.

칼슘의 수준별 급여 및 25-hydroxycholecalciferol의 사료 내 첨가가 종란 생산성 및 후기 난각질에 미치는 영향

본 실험에서는 사료 내 Ca 공급 수준의 증가 및 25-<TEX>$(OH)D_3$</TEX>의 첨가 급여가 산란종계에서 후기 난각질 강화 및 종란 생산성에 미치는 영향을 검토하기 위한 목적으로 수행하였다. 60주령 Hy-Line Brown 산란종계 암탉 540수와 수탉 54수를 공시하여 사료 내 Ca을 3.3%, 3.9% 및 4.5% 로 하고, 25-<TEX>$(OH)D_3$</TEX>를 각각 0, 75 및 <TEX>$150{\mu}g/kg$</TEX> 수준으로 첨가한 총 9개 실험사료를 10주간 급여하였다. 주별로 사료섭취량을 조사하였고, 산란율과 난중은 매일 조사하였다. 종란율과 부화율 조사를 위해 생산된 종란을 주별로 처리하였다. 실험사료 급여 후 주별로 생산된 계란을 반복구별로 10개씩 수집하여 난각질 측정에 이용하였다. 실험 종료 시 반복구별로 평균체중이 비슷한 개체를 선발하여 채혈 후 희생시킨 다음 경골을 적출하였다. 채취한 경골은 화학적 조성의 분석을 위한 시료로 이용하였고, 얻어진 혈액에서도 성분 분석을 실시하였다. 산란율은 Ca 3.9% 첨가구가 Ca 3.3%와 Ca 4.5% 첨가구에 비해 유의한 증가가 나타났으며(P<0.01), 25-<TEX>$(OH)D_3$</TEX>의 무첨가구에서 25-<TEX>$(OH)D_3$</TEX> 첨가구에 비해 유의하게(P<0.01) 높게 나타났다. 난각강도는 Ca 4.5% 첨가구가 Ca 3.9%와 Ca 3.3% 첨가구에 비해 유의하게 개선되었으며(P<0.01), 25-<TEX>$(OH)D_3$</TEX> <TEX>$150{\mu}g/kg$</TEX> 첨가구에서 25-<TEX>$(OH)D_3$</TEX> <TEX>$70{\mu}g/kg$</TEX> 첨가구와 25-<TEX>$(OH)D_3$</TEX> 무첨가구에 비해 유의하게 개선되었다(P<0.01). 수정율은 Ca 급여수준 변화 및 25-<TEX>$(OH)D_3$</TEX>의 첨가 급여에 따라 처리구간에 큰 차이는 없는 것으로 나타났으나, 입란대 부화율은 25-<TEX>$(OH)D_3$</TEX> <TEX>$150{\mu}g/kg$</TEX> 첨가구에서 25-<TEX>$(OH)D_3$</TEX> 무첨가구에 비해 유의하게(P<0.05) 높게 인정되었다. 경골내 Ca 함량은 Ca 4.5% 급여구에서 Ca 3.3% 급여구 및 Ca 3.9% 급여구에 비해 유의한 차이가 나타났으나(P<0.05), 25-<TEX>$(OH)D_3$</TEX>의 첨가 효과는 인정되지 않았다. 상기의 결과로부터 산란종계의 후기 난각질 개선을 위해서는 사료 내의 Ca 수준을 비교적 높게 설정하는 것이 유리하며, 25-<TEX>$(OH)D_3$</TEX>의 첨가에 의해서도 난각질이 개선될 수 있는 것으로 나타났다. 또한 25-<TEX>$(OH)D_3$</TEX>를 <TEX>$150{\mu}g/kg$</TEX> 첨가에 의해 입란대 부화율이 유의하게 개선되는 결과가 시사되었다. 그러나 25-<TEX>$(OH)D_3$</TEX>를 <TEX>$150{\mu}g/kg$</TEX> 수준으로 첨가했을 때 관찰된 산란율의 저하에 대해서는 그 원인을 밝히기 위한 추가적인 연구가 필요하겠다. This experiment was conducted to investigate the effects of dietary calcium (Ca) and vitamin <TEX>$D_3$</TEX> metabolite on eggshell quality and hatching egg production in aged egg-type breeder hens. A total of five hundred and forty 60-week-old Hy-Line Brown breeder hens were randomly allocated to nine treatments in a <TEX>$3\times3$</TEX> factorial design to determine the effects of dietary Ca levels (3.3, 3.9, and 4.5%), combined with three levels of 25-hydroxycholecalciferol [25-<TEX>$(OH)D_3$</TEX> 0, 75, and <TEX>$150{\mu}g/kg$</TEX>], on eggshell quality and egg production for 10 weeks. There were significant Ca and 25-<TEX>$(OH)D_3$</TEX> effects (P<0.01) on egg production rate. There was a linear (P<0.01) increase in eggshell strength and thickness with increasing dietary Ca and 25-<TEX>$(OH)D_3$</TEX> levels. Dietary 25-<TEX>$(OH)D_3$</TEX> had a significant effect (P<0.05) on hatchability of egg although fertility was not influenced by dietarylevels of Ca and 25-<TEX>$(OH)D_3$</TEX>. Dietary Ca levels affected Ca content in tibia (P<0.05). These results indicated that relatively high levels of dietary Ca in combination with 25-<TEX>$(OH)D_3$</TEX> had a beneficial effect on improving eggshell quality and reproductive performance in aged egg-type breeder hens.

Diet Calcium Level but Not Calcium Supplement Particle Size Affects Bone Density and Mechanical Properties in Ovariectomized Rats ,

Calcium (Ca) supplements, especially Ca carbonate (CaCO3), are the main alternative sources of dietary Ca and an important part of a treatment regimen for osteoporosis, the most common metabolic bone disorder of aging and menopause. In a female ovariectomized (OVX) rat model for studying postmenopausal osteoporosis, we tested the hypothesis that a small compared with a large particle size of CaCO3 (13.0- vs. 18.5-μm geometric diameter) would result in increased Ca balance and subsequently bone mass and that this would be affected by dietary Ca level. We used 6-mo-old rats that were OVX either at 6 or 3 mo of age as models of early or stable menopausal status, respectively. The rats received semipurified diets that contained either 0.4 or 0.2% dietary Ca provided from CaCO3 of 2 particle sizes. A group of Sham-operated rats with intact ovaries served as control and were fed 0.4% dietary Ca from large particles. Estrogen deficiency as a result of ovariectomy had an adverse effect on bone density, mineral content, and bone mechanical properties (P < 0.001). Reducing dietary Ca from 0.4 to 0.2% resulted in significant adverse effects on bone density and mechanical properties (P < 0.001). The particle size of CaCO3 did not affect total Ca balance, bone dual energy X-ray absorptiometry and peripheral quantitative computed tomography indices, bone ash and Ca content, or the mechanical determinants of bone strength. We conclude that a decrease in particle size of CaCO3 to 70% of that typically found in Ca supplements does not provide a benefit to overall Ca metabolism or bone characteristics and that the amount of Ca consumed is of greater influence in enhancing Ca nutrition and skeletal strength.

Calcium levels and limestone particle size in the diet of commercial layers at the end of the first production cycle

This study evaluated the effect of dietary calcium levels and limestone particle size distribution on first-cycle layer performance and egg quality. A completely randomized experimental design in 4x3 factorial arrangement (four Ca levels - 3.0, 3.5, 4.0, 4.5%; and three limestone particle size distributions - 100% fine, 50% fine and 50% coarse, 30% fine and 70% coarse) was applied, totaling 12 treatments with six replicates of eight birds each. The treatments did not influence the most of evaluated performance and internal and external egg quality parameters. However, limestone particle size distribution quadratically affected with percentage of defective eggs, with the lowest percentage obtained with the distribution 61.75% fine limestone and 38.25% coarse limestone. Increasing dietary Ca levels significantly increased eggshell weight per surface area and the percentage of Ca excreted in the feces. It was concluded that the combination of the highest dietary Ca level (4.5%) with 50% replacement of fine-particle limestone by coarse limestone results in better eggshell and increases the number of marketable eggs.

Exigências de cálcio para codornas japonesas fêmeas de um a 35 dias de idade

Two trials were carried out to determine calcium requirements for better performance, and calcium (Ca) and phosphorus (P) deposition in the tibia and femur of Japanese quails aged 1 to 35 days. Two hundred and ten female quails were allocated in a completely randomized experimental design, with seven treatments, three repetitions and ten birds per experimental unit. The treatments consisted of a basal diet supplemented with limestone in order to produce the following Ca levels: 0.85; 1.00; 1.15; 1.30; 1.45; 1.60 and 1.75% in the initial phase (1 to 21 days) and 0.53; 0.68; 0.83; 0.98; 1.13; 1.28 and 1.43% in the growing phase (22 to 35 days). In the initial phase, feed intake, weight gain and feed conversion showed quadratic response to dietary Ca levels, as well as on the content of Ca in the tibia and femur of quails. In the growing phase, only feed conversion was significantly affected. Dietary calcium levels recommended for the initial and growing phases are 1.26 and 0.87%, respectively.

Calcium and available phosphorus levels for laying hens in second production cycle

This experiment studied the effect of four calcium (3.0, 3.5, 4.0, and 4.5%) and four available phosphorus levels (0.25, 0.30, 0.35, and 0.40%) in the diet of semi-heavy commercial layers after molting. Hisex Brown ® layers between 90 and 108 weeks of age were distributed in a completely randomized experimental design with a 4x4 factorial arrangement with 16 treatments of five replicates of eight birds each. mortality, egg production, feed intake, egg mass, average egg weight, calcium and phosphorus intake, feed conversion ratio (per dozen eggs and per kg eggs), eggshell percentage and thickness, eggshell strength, eggshell weight per surface area (ESWSA), yolk percentage and color, albumen percentage, albumen and yolk heights, and blood and excreta calcium and phosphorus concentrations. There was no interaction (P>0.05) between dietary Ca and avP for any of the studied parameters. There were linear increases in Ca intake (P 0.05) by dietary Ca and avP levels. The diet containing 4.5% calcium improved feed conversion ratio per dozen eggs and eggshell quality. The lowest avP level fed (0.25%) is sufficient to maintain the performance and the egg quality of semi-heavy commercial layers after molting.