Digestibility Of Calcium Research Articles

Techniques for evaluating digestibility of energy, amino acids, phosphorus, and calcium in feed ingredients for pigs.

Sound feed formulation is dependent upon precise evaluation of energy and nutrients values in feed ingredients. Hence the methodology to determine the digestibility of energy and nutrients in feedstuffs should be chosen carefully before conducting experiments. The direct and difference procedures are widely used to determine the digestibility of energy and nutrients in feedstuffs. The direct procedure is normally considered when the test feedstuff can be formulated as the sole source of the component of interest in the test diet. However, in some cases where test ingredients can only be formulated to replace a portion of the basal diet to provide the component of interest, the difference procedure can be applied to get equally robust values. Based on components of interest, ileal digesta or feces can be collected, and different sample collection processes can be used. For example, for amino acids (AA), to avoid the interference of fermentation in the hind gut, ileal digesta samples are collected to determine the ileal digestibility and simple T-cannula and index method are commonly used techniques for AA digestibility analysis. For energy, phosphorus, and calcium, normally fecal samples will be collected to determine the total tract digestibility, and therefore the total collection method is recommended to obtain more accurate estimates. Concerns with the use of apparent digestibility values include different estimated values from different inclusion level and non-additivity in mixtures of feed ingredients. These concerns can be overcome by using standardized digestibility, or true digestibility, by correcting endogenous losses of components from apparent digestibility values. In this review, methodologies used to determine energy and nutrients digestibility in pigs are discussed. It is suggested that the methodology should be carefully selected based on the component of interest, feed ingredients, and available experimental facilities.

Dietary maifanite supplementation did not affect the apparent total tract digestibility of calcium and phosphorus in growing pigs.

ObjectiveThis study was conducted to determine the effects of dietary maifanite supplementation and fecal collection method on the apparent total tract digestibility (ATTD) of calcium (Ca) and phosphorus (P) and blood parameters in growing pigs.MethodsThirty-six growing barrows (Duroc×Landrace×Yorkshire; 27.0±2.6 kg) were allotted to six dietary treatments with 6 pigs per treatment according to body weight in a completely randomized design. The experimental treatments were: i) Low Ca+cornstarch (2.25%), ii) Low Ca+maifanite (2.25%), iii) Medium Ca+cornstarch (1.42%), iv) Medium Ca+maifanite (1.42%), v) High Ca+cornstarch (0.64%), and vi) High Ca+maifanite (0.64%). Feces were collected by the total collection (TC) and indicator method (IM). At the beginning and the end of the experiment, blood samples were collected from each pig.ResultsFor the TC method, there were no difference in Ca intake, fecal Ca output, Ca retention and the ATTD of Ca between cornstarch and maifanite diets at the same dietary Ca level. However, urinary Ca excretion was lower (p = 0.01) in pigs fed low Ca diets without maifanite supplementation compared with other dietary treatments. Dietary maifanite supplementation had no effect on the P metabolism in growing pigs. For the IM method, there was no difference in Ca digestibility between cornstarch and maifanite diets at the same dietary Ca level. The ATTD of P was greater (p<0.01) in pigs fed the high Ca diet with maifanite supplementation compared with the high Ca diet with cornstarch treatment. Dietary inclusion of maifanite had no effect on blood parameters in growing pigs.ConclusionDietary maifanite supplementation had no effect on the ATTD of Ca and P and serum parameters in growing pigs. The IM resulted in lower digestibility values than the TC method.

Effects of graded levels of microbial phytase on apparent total tract digestibility of calcium and phosphorus and standardized total tract digestibility of phosphorus in four sources of canola meal and in soybean meal fed to growing pigs.

One hundred twenty pigs were used to determine effects of graded levels of microbial phytase on the apparent total tract digestibility (ATTD) of P and Ca and the standardized total tract digestibility (STTD) of P in 4 sources of canola meal and in 1 source of soybean meal (SBM) fed to growing pigs. The 4 sources of canola meal were produced from 1 source of high-protein canola seeds and 2 sources of conventional canola seeds with 1 of the conventional canola seeds being divided into 2 separate batches before crushing. Pigs (16.2 ± 5.3 kg initial BW) were individually housed in metabolism crates and were randomly allotted to 1 of 20 diets in a 5 × 4 factorial arrangement of treatments with 5 ingredients and 4 levels of phytase. There were 6 replicate pigs per diet. Five basal diets based on high-protein canola meal (CM-HP), high-temperature processed canola meal (CM-HT), low-temperature processed canola meal (CM-LT), conventional canola meal (CM-CV), or SBM were formulated. The basal diets contained no phytase. Fifteen additional diets were prepared by adding approximately 500, 1,500, or 2,500 phytase units/kg to each of the 5 basal diets. Feces were quantitatively collected for 5 d based on the marker-to-marker approach after a 7-d adaptation period. Results indicated that supplementation of microbial phytase increased (linear, < 0.05) the ATTD of Ca in diets containing CM-HP, CM-HT, CM-CV, and SBM but not in diets containing CM-LT. Microbial phytase also increased (linear and quadratic, < 0.05) the ATTD and STTD of P in all 5 ingredients. Compared with the CM-CV diets, the CM-HP diets had greater ( < 0.05) ATTD of Ca. The ATTD of Ca in the SBM diet was greater ( < 0.05) than in all canola meal diets, but no differences were observed in ATTD of Ca between CM-HT and CM-LT diets. The ATTD and the STTD of P were less ( < 0.05) in CM-HP, CM-HT, CM-LT, or CM-CV than in SBM if no microbial phytase was added, but no differences were observed in the ATTD and STTD of P in SBM, CM-HP, CM-HT, or CM-CV if the highest amount of phytase were added (interaction, < 0.05). Regression equations were developed to calculate the response to microbial phytase on the STTD of P in CM-HP, CM-HT, CM-LT, CM-CV, and SBM. In conclusion, inclusion of graded levels of microbial phytase increased the ATTD and STTD of P in CM-HP, CM-HT, CM-LT, CM-CV, and SBM and the response to microbial phytase added to each ingredient can be predicted by regression equations.

182 True total-tract digestibility of calcium in limestone and dicalcium phosphate for twenty-kilogram pigs are additive in a semi-purified diet

182 True total-tract digestibility of calcium in limestone and dicalcium phosphate for twenty-kilogram pigs are additive in a semi-purified diet

178 Effects of zinc oxide and microbial phytase on standardized total tract digestibility of calcium in maize-based diets fed to growing pigs

178 Effects of zinc oxide and microbial phytase on standardized total tract digestibility of calcium in maize-based diets fed to growing pigs

Evaluasi Proteksi Sabun Kalsium Sebagai Pakan Suplemen Berdasarkan Kecernaan Bahan Kering, Kecernaan Bahan Organik dan pH In Vitro di dalam Rumen dan Pasca Rumen

The research aims to evaluate calsium soap protection as feed supplement based on dry matter&lt;br /&gt;digestibility, organic matter digestibility and pH in vitro in the rumen and post rumen. Calsium soap&lt;br /&gt;was produced from sardine fish oil and soybean meal, through two protection methods. It was&lt;br /&gt;saponification and microencapsulation. This research used Split Subject Repeated Measurement&lt;br /&gt;Design with 3 treatments (calcium soap, soybean meal and pangola grass) which each treatment was&lt;br /&gt;repeated 5 times. The observation kinetics of dry matter digestibility, organic matter digestibility, and&lt;br /&gt;pH rumen fluid were done in incubation times (2, 4, 8, 12, 24 and 48 hours respectively). The first&lt;br /&gt;results of the research showed that in the first step (rumen) has dry matter digestibility of calcium&lt;br /&gt;soaps: 38.65; 40.00; 42.66; 46.32; 54.40 and 51.40% respectively; organic matter digestibility: 39.44;&lt;br /&gt;41.27; 44, 31; 46.32; 56.62 and 52.50% respectively. Kinetics of pH rumen fluid: 6.89; 6.79; 6.78;&lt;br /&gt;6.74; 6.71, and 6.88 respectively. In the second step (post rumen), the digestibility of calsium soap&lt;br /&gt;production has dry matter digestibility of 74.85% and organic matter of digestibilty of 72.94%. The&lt;br /&gt;results could be concluded that in the rumen, calcium soap is the most microbial degradation resistant&lt;br /&gt;compared the others and it can be degraded and digested in the abomasum to the small intestine.&lt;br /&gt;Therefore pH of rumen fluid is optimal, so it does not interfere with the fermentation in the rumen.&lt;br /&gt;Keywords: calsium soap, in vitro, dry matter digestibily, organic matter digestibility, pH value

Evaluasi Proteksi Sabun Kalsium Sebagai Pakan Suplemen Berdasarkan Kecernaan Bahan Kering, Kecernaan Bahan Organik dan pH In Vitro di dalam Rumen dan Pasca Rumen

The research aims to evaluate calsium soap protection as feed supplement based on dry matter&lt;br /&gt;digestibility, organic matter digestibility and pH in vitro in the rumen and post rumen. Calsium soap&lt;br /&gt;was produced from sardine fish oil and soybean meal, through two protection methods. It was&lt;br /&gt;saponification and microencapsulation. This research used Split Subject Repeated Measurement&lt;br /&gt;Design with 3 treatments (calcium soap, soybean meal and pangola grass) which each treatment was&lt;br /&gt;repeated 5 times. The observation kinetics of dry matter digestibility, organic matter digestibility, and&lt;br /&gt;pH rumen fluid were done in incubation times (2, 4, 8, 12, 24 and 48 hours respectively). The first&lt;br /&gt;results of the research showed that in the first step (rumen) has dry matter digestibility of calcium&lt;br /&gt;soaps: 38.65; 40.00; 42.66; 46.32; 54.40 and 51.40% respectively; organic matter digestibility: 39.44;&lt;br /&gt;41.27; 44, 31; 46.32; 56.62 and 52.50% respectively. Kinetics of pH rumen fluid: 6.89; 6.79; 6.78;&lt;br /&gt;6.74; 6.71, and 6.88 respectively. In the second step (post rumen), the digestibility of calsium soap&lt;br /&gt;production has dry matter digestibility of 74.85% and organic matter of digestibilty of 72.94%. The&lt;br /&gt;results could be concluded that in the rumen, calcium soap is the most microbial degradation resistant&lt;br /&gt;compared the others and it can be degraded and digested in the abomasum to the small intestine.&lt;br /&gt;Therefore pH of rumen fluid is optimal, so it does not interfere with the fermentation in the rumen.&lt;br /&gt;Keywords: calsium soap, in vitro, dry matter digestibily, organic matter digestibility, pH value

Procedures for determining digestibility of amino acids, lipids, starch, fibre, phosphorus, and calcium in feed ingredients fed to pigs

The proportion of nutrients that is absorbed from the intestinal tract of the pig differs among dietary ingredients; therefore, it would be desirable to determine the proportion of nutrients that is absorbed for each ingredient, but, for practical reasons, values for the digestibility of nutrients in each ingredient are used as predictors of absorption. For amino acids, starch and lipids, ileal digestibility must be determined because nutrients not absorbed in the small intestine will be fermented or changed in the large intestine, which invalidates data for total tract digestibility of these nutrients. For starch, apparent ileal digestibility is a reasonable predictor of its disappearance from the small intestine, but because of endogenous secretions of amino acids and lipids into the small intestine, standardised ileal digestibility of amino acids and true ileal digestibility of fat must be determined. For fibre, total tract digestibility is used to estimate fermentation and subsequent absorption of short-chain fatty acids, but it must be corrected for endogenous secretions. Likewise, for phosphorus and calcium, values for apparent total tract digestibility must be corrected for basal endogenous losses; consequently, standardised total tract digestibility of phosphorus and calcium is calculated and used in diet formulation. These procedures for determining the digestibility of nutrients in feed ingredients make it possible to formulate diets in which concentrations of digestible nutrients can be predicted from values for individual feed ingredients.

Effects of zinc oxide and microbial phytase on digestibility of calcium and phosphorus in maize-based diets fed to growing pigs

Effects of zinc oxide and microbial phytase on digestibility of calcium and phosphorus in maize-based diets fed to growing pigs

Effects of zinc oxide and microbial phytase on digestibility of calcium and phosphorus in maize-based diets fed to growing pigs.

An experiment was conducted to test the hypothesis that inclusion of Zn at a pharmacological level in diets fed to pigs affects apparent total tract digestibility (ATTD) of Ca and P and standardized total tract digestibility (STTD) of Ca. The second hypothesis was that inclusion of microbial phytase increases the ATTD of Ca and P and the STTD of Ca regardless of the concentration of Zn in the diet. Fifty-six growing barrows (15.4 ± 1.9 kg average BW) were allotted to a randomized complete block design with 7 dietary treatments and 8 pigs per treatment. A maize-based basal diet was formulated with either 0 or 2,400 mg/kg Zn from ZnO and 0, 1,000, or 3,000 units of phytase (FTU) per kilogram. A Ca-free diet was used to determine basal endogenous losses of Ca. Experimental diets were fed for 13 d, and feces were collected from the feed provided from d 6 to 11 using the marker-to-marker approach; urine was also collected from d 6 to 11. Retention of Ca, ATTD of Ca, and STTD of Ca increased ( < 0.01) as the concentration of phytase in the diet increased and were less ( < 0.01) if ZnO was used than if no ZnO was added to the diet. Retention of P and the ATTD of P increased ( < 0.0001) as the concentration of phytase increased in the diet, but the increase was greater if ZnO was not added than if ZnO was added to the diet (interaction, < 0.05). In conclusion, pharmacological levels of Zn reduced Ca and P digestibility and retention, but this effect was partly ameliorated by the inclusion of phytase in the diets. Inclusion of microbial phytase increased the ATTD and STTD of Ca in diets and also the ATTD of P.

Effects of dietary xylooligosaccharides on the performance, egg quality, nutrient digestibility and plasma parameters of laying hens

This study was conducted to determine the effects of dietary supplementation with xylooligosaccharides (XOS) on the laying performance, egg quality, nutrient digestibility and plasma parameters of Lohmann hens. A total of 1080 Lohmann laying hens (28 weeks of age) were assigned to six treatment diets that included XOS at concentrations of 0, 0.1, 0.2, 0.3, 0.4 or 0.5g/kg for 8 weeks. Each treatment had six replicates with 10 cages (3 birds/cage). Egg production, egg weight and feed intake were recorded daily. Egg quality traits were recorded every 4 weeks. Plasma parameters were evaluated, and a metabolic experiment using 36 birds from each replicate was conducted at the end of the study. The results show that XOS supplementation had no effect on the production performance but could significantly improve the quality of the eggshell; eggshell thickness and eggshell relative weight showed a linear or quadratic response to increasing dietary XOS (P<0.05). However, XOS supplementation did not influence other egg quality characteristics, such as yolk relative weight, Haugh unit, yolk color and shell strength. On the other hand, XOS supplementation could significantly increase the apparent digestibility of the calcium (P<0.05). Moreover, plasma glutamic–pyruvic transaminase (GPT), cholesterol, high-density lipoprotein (HDL), and very low-density lipoprotein (VLDL) decreased linearly (P<0.05) with the increasing dietary XOS concentration. XOS can be concluded to be an effective feed additive because it improves the quality of the eggshell by increasing the apparent digestibility of calcium and because it decreases the plasma GPT, cholesterol, HDL, and VLDL of laying hens.

Effect of calcium source and particle size on the true ileal digestibility and total tract retention of calcium in broiler chickens

The influence of calcium (Ca) source and particle size on true ileal digestibility coefficient (TIDC) of Ca and apparent total tract retention coefficient (ATTRC) of Ca in broilers was assessed. Four experimental diets containing limestone and oyster shell, each as fine (<0.5mm) and coarse (1–2mm) particles, were fed to broiler chickens from 21 to 24days of age. A Ca- and phosphorus-free diet was used to determine the ileal endogenous Ca losses. Limestone and oyster shell were obtained from commercial sources and ground to pass through a set of sieves to obtain the fine and coarse particles. Titanium dioxide was incorporated in all diets as an indigestible marker. Each experimental diet was randomly allotted to six replicate cages (eight birds per cage). Apparent ileal digestibility coefficient and ATTRC of Ca were calculated using the indicator method and the TIDC values were calculated by correcting for endogenous Ca losses. Ileal endogenous Ca losses were determined to be 115mg/kg of dry matter intake. The main effect of Ca source and the interaction between Ca source and particle size were not significant (P>0.05) for the TIDC and ATTRC of Ca. Both TIDC and ATTRC of Ca were influenced (P<0.05) by particle size, with coarser particles increasing the digestibility and retention values. Increased particle size increased the TIDC of Ca in limestone from 0.38 to 0.62 and that of oyster shell from 0.33 to 0.56. The corresponding increases in ATTRC of Ca were from 0.44 to 0.66 in limestone and from 0.40 to 0.60 in oyster shell. Calcium concentration in the gizzard contents of birds was higher (P<0.05) for limestone as compared to oyster shell and increased with increase in particle size. Calcium concentration in the gizzard contents was strongly correlated with the TIDC (r=0.81; P<0.01) and ATTRC (r=0.82; P<0.01) of Ca. A strong correlation (r=0.80, P<0.01) was also observed between TIDC and ATTRC of Ca.

Nutrient utilization in grower pigs fed boiled, ensiled or milled sweet potato roots blended with a wheat-based protein concentrate

Sweet potato (SP) roots are highly palatable and digestible for pigs as fresh, boiled, ensiled or dried feed. The form of presentation and blending with other highly digestible protein ingredients could improve nutrient utilization by grower pigs. A metabolic experiment was conducted utilising a 4×4 Latin Square design with four (Landrace×Large White)×Duroc pigs at nine weeks of age (26.5±1.4kg), where four dietary treatments offered ad libitum over four consecutive eight-day feeding periods tested the hypothesis that there would be no difference in nutrient digestibility and utilization in pigs fed SP roots when prepared as boiled (BR), ensiled (ER) or milled roots (MR) and blended with a complementary protein concentrate, and compared against a standard wheat-based pig feed (STD). SP products were blended with protein concentrate at 43%:57% DM, and provided total lysine:DE ratios of 0.57, 0.58, 0.60 and 0.58g/MJ DE for BR43, ER43, MR43 and STD respectively. DM intake, ADG and FCR were similar (p>0.05) among treatments. Coefficient of apparent total tract digestibility (CATTD) of DM, OM, fibre, calcium, total phosphorus and energy retention (%) in SP root diets were superior to STD (p<0.05). Ash CATTD of ER43 and MR43 were improved over STD whereas BR43 was similar to all three diets. CATTD of fats (EE) was similar. Protein (CP) CATTD of BR43 was superior to MR43 and STD whereas ER43 was similar to the other three diets. N intake (g/d), N digestibility (% intake) and N utilization (% digested) were similar. N retained on STD (30.6gN/d) and MR43 (30.4gN/d) were similar. The much higher N retained on BR43 (35.4gN/d) and ER43 (35.8gN/d) was due to a significant shift in N loss from urine (8.2 and 7.0gN/d) to faeces (13.7 and 10.1gN/d) which, combined with greater OM digestibility and energy retention, suggested increased microbial use of N in the hindgut. The SP diets were highly digestible and provided improved nutrient utilization, ADG and FCR in pigs compared to the wheat-based commercial feed.

Effect of feeding sows PVMA Intermiks on digestibility and metabolism of pigs

Pork production in modern conditions associated with the use of feed and dietary supplements as part of diets, because without them to provide animals essential nutrients almost impossible. Especially for little Ingredient grain rations. Therefore have resorted to creating new PVMA. These concerns and PVMA Intermiks PS – 7.5% and Intermiks LS – 20% – according to gestation and lactating sows. So were conducting research on the influence of feeding PVMA Intermiks sows in different periods of the reproductive cycle of feed digestibility and metabolism of nitrogen, calcium and phosphorus in their piglets weaned at 28 days age. Research groups conducting two–analogues pigs of large white breed balance method, under which the pigs were kept in individual cages and accounted for eight days consumed feed, feces and urine color. The live weight per head was 9 kg. Sows experimental group during 85 days gestating 7.5% by weight was replaced grain mix PVMA Intermiks PS, and next to farrowing and weaning piglets at 28 days age, replaced 20% concentrated feed on PVMA Intermiks LS. Sows in the control group were kept in complete feed appropriate. After all born piglets up to 14 days eating a special supplement Intermiks SP «Bambino» – 25%, and from 14 to 28 days – Intermiks SP – 25%. Studies have shown that feeding sows PVMA Intermiks increases performance polycarpous 10.8% weight in the pig–breeding nests by 25.3% and 13.3% macrocarpa. The weight of a piglet at birth the control and the experimental groups was 1.05 and 1.19 kg and at weaning at 28 days of life – 8.52 and 9,1 kg. Piglets from sows receiving PVMA Intermiks had higher levels of digestibility of crude oil (3.3%) and fiber (to 5.37%). No significant difference was obtained for the digestibility of dry, organic matter and protein compared to piglets from sows with complete feed in the diet. In the experimental pigs tends to increase the number of nitrogen retained in the body (14.5 %) and from the accepted and digested (by 4.4 and 6.0%). Terms feeding lactating sows gestation and no likely impact on calcium and phosphorus in pigs weaned at 28 days age.

0924 Effects of microbial phytase on the apparent and standardized total tract digestibility of calcium in milk co-products fed to growing pigs

0924 Effects of microbial phytase on the apparent and standardized total tract digestibility of calcium in milk co-products fed to growing pigs

0974 Effect of increasing concentrations of digestible calcium and digestible phosphorus on apparent total tract digestibility of calcium and phosphorus by pigs

0974 Effect of increasing concentrations of digestible calcium and digestible phosphorus on apparent total tract digestibility of calcium and phosphorus by pigs

Digestibilidade aparente de farinha de carne e ossos de peixe para tilápia do Nilo

Este trabalho foi realizado com o objetivo de determinar a digestibilidade aparente da proteína bruta, extrato etéreo, energia bruta, cálcio e fósforo das farinhas de carne e ossos de tilápia do Nilo (Oreochromis niloticus), do catfish (Ictalurus punctatus), do pintado (Pseudoplatystoma corruscans) e do bagre africano (Clarias gariepinus) para a tilápia do Nilo. Para tal, foi utilizado o método indireto, com o uso do óxido de cromo (III) (Cr2O3), como indicador inerte, incorporado na ração em 1 g·kg-1. Foram distribuídas 400 tilápias com 50±7,89 g (média ± DP) em 20 tanques cônicos em um delineamento experimental inteiramente ao acaso, constituído por cinco tratamentos com quatro repetições. Os tratamentos foram compostos de uma dieta referência e outras quatro dietas constituídas de 800 g·kg-1 da dieta referência e 200 g·kg-1 da farinha de carne e ossos de tilápias, catfish, pintado e bagre africano. A farinha de carne e ossos de pintado demonstrou melhor digestão para proteína bruta, cálcio e fósforo, enquanto a farinha de carne e ossos de tilápia obteve valor maior para extrato etéreo e energia digestível. Para matéria mineral, o maior resultado obtido foi para a farinha de carne e ossos de catfish. Os resultados deste estudo sugerem que a tilápia do Nilo apresenta limitada capacidade para digerir e utilizar os componentes presentes nas farinhas de ossos avaliadas. A presença de grande quantidade de colágeno estrutural nesses ingredientes e sua baixa digestibilidade pode ter causado redução na disponibilidade do cálcio e fósforo.

Effects of a novel 6-phytase (EC 3.1.3.26) on performance, phosphorus and calcium digestibility, and bone mineralization in weaned piglets

Effects of a novel 6-phytase (EC 3.1.3.26) on performance, phosphorus and calcium digestibility, and bone mineralization in weaned piglets

Effect of limestone particle size and calcium to non-phytate phosphorus ratio on true ileal calcium digestibility of limestone for broiler chickens

The purpose of this study was to determine the effect of limestone particle size and calcium (Ca) to non-phytate phosphorus (P) ratio on the true ileal Ca digestibility of limestone for broiler chickens. A limestone sample was passed through a set of sieves and separated into fine (<0.5 mm) and coarse (1–2 mm) particles. The analysed Ca concentration of both particle sizes was similar (420 g/kg).Six experimental diets were developed using each particle size with Ca:non-phytate P ratios of 1.5:1, 2.0:1 and 2.5:1, with ratios being adjusted by manipulating the dietary Ca concentrations. A Ca-free diet was also developed to determine the basal ileal endogenous Ca losses. Titanium dioxide (3 g/kg) was incorporated in all diets as an indigestible marker.Each experimental diet was randomly allotted to 6 replicate cages (8 birds per cage) and fed from d 21 to 24 post hatch. Apparent ileal digestibility of Ca was calculated using the indicator method and corrected for basal endogenous losses to determine the true Ca digestibility.The basal ileal endogenous Ca losses were determined to be 127 mg/kg of dry matter intake.Increasing Ca:non-phytate P ratios reduced the true Ca digestibility of limestone. The true Ca digestibility coefficients of limestone with Ca:non-phytate P ratios of 1.5, 2.0 and 2.5 were 0.65, 0.57 and 0.49, respectively.Particle size of limestone had a marked effect on the Ca digestibility, with the digestibility being higher in coarse particles (0.71 vs. 0.43).

Comparison of apparent ileal and total tract digestibility of calcium in calcium sources for pigs

Two experiments were conducted to compare apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of calcium (Ca) in pigs. In experiment 1, three semipurified diets with soybean meal, canola meal, or sunflower meal as the sole source of Ca were formulated. Eighteen cannulated pigs (initial BW = 66 ± 5 kg) were assigned in a randomized complete block design to three treatments and six replicates per treatment. Results indicated that for either Ca or phosphorus (P), the ATTD was not different from the AID in the three diets (Psite = 0.16 and 0.81, respectively). In experiment 2, diets with four Ca concentrations were formulated with calcium carbonate as the Ca source. Sixteen cannulated pigs (initial BW = 73 ± 4 kg) were assigned in a randomized complete block design to four treatments in two experimental periods. The results indicated that the ATTD of Ca was not different from the AID for all diets. Furthermore, the Ca digestibility was not affected by dietary treatments, but the P digestibility was linearly improved (P &lt; 0.01) as dietary Ca and P concentrations increased. Thus, it is concluded that both AID and ATTD can be used to describe the digestibility of Ca for growing–finishing pigs.