Apparent Ileal Digestibility Of Ca Research Articles

54 Effects of a new biosynthetic 6-phytase supplementation on nutrient digestibility, phytate disappearance and growth efficiency in weaning piglets fed low in calcium and digestible phosphorus diets

Abstract The objective of this study was to investigate the influence of adding graded levels of a new biosynthetic bacterial 6-phytase on nutrient digestibility, phytate disappearance and growth performance in weaned piglets. A total of 192 male weaned piglets with initial body weight of 8.70 ± kg, distributed in a randomized block design with four treatments and 24 replicate pens with 2 animals each for 42 d. The experimental diets included a phosphorus and Ca deficient diet (STTD of P/Ca = 0.21%/0.58% and 0.19%/0.54%, respectively, in post-weaning 1 and 2 diets) containing 0 (a control diet), 500, 1,000 or 1,500 FTU/kg diet. The diets were fed into 2 phases: post-weaning 1 and 2 from 1 to 14 and 15 to 42 d, respectively. Body weight and feed intake were measured at the end of each phase, and average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated for the overall experimental period. On d 42, ileal digesta samples were collected from 1 piglet/pen (n = 12 samples/treatment) for apparent ileal digestibility (AID) of Ca, P, and amino acids and phytate disappearance determination. Supplementation of diet with phytase from 0 to 1500 FTU/kg diet linearly improved (P < 0.01) AID of Ca. Both linear and quadratic effects (P < 0.001) was observed for AID of P and phytate-P. Increasing level of phytase supplementation resulted in linear and quadratic increases of Arg, His, Ile, Leu, Lys, Phe, Thr, Trp, Val, Ala, Asp, Cys, Glu, Ser, Tyr and total amino acids. Phytase supplementation increased (P < 0.0001) linearly Met and Pro, with an AID of Met showing a tendency (P = 0.09) for a quadratic increase. In addition, increasing phytase dose linearly increased (P = 0.006) the overall ADFI and ADG and decreased (P < 0.001) F:G ratio. Also, a tendency (P = 0.07) for quadratic effect of phytase was also observed on F:G ratio. These findings highlight that the supplementation of diets with the new bacterial 6-phytase significantly enhanced the utilization of nutrients, disappearance of phytate and performances of weaned piglets in a dose dependent manner.

Digestible calcium equivalency of phytase and nutrient utilization of broiler chickens fed graded levels of limestone or phytase during the starter phase

The current study aimed to quantify the digestible Calcium (Ca) equivalency of a new phytase (HiPhoriusTM) in broiler chickens. A total of 1,152 male Cobb 500 broiler chickens were used in an experiment in which 8 diets consisting of graded levels of Ca supplied with limestone or graded levels of the phytase were fed. The 8 dietary treatments were based on a corn-soybean meal diet containing 5.1 g/kg of Ca and 5.1 g/kg of phosphorus (P) as negative control (NC); the NC + 1.3, 2.6, or 3.9 g/kg of Ca from limestone; and the NC + 500, 1000, 2000, or 4000 FYT/kg of phytase. Birds were fed the experimental diets for 3 d (from d 7 to 10) or 14 d (from d 7 to 21) to determine apparent ileal digestibility (AID) and apparent total tract retention (ATTR) of dry matter (DM), CP, Ca, and P. In the 10-d-old birds, increasing the levels of Ca decreased the AID of P and Ca (linear, P < 0.05). Increasing the levels of phytase quadratically improved (P < 0.05) the AID of Ca and P. The AID of DM and CP in the younger birds quadratically increased (P < 0.05) as the levels of Ca increased. There were linear and quadratic effects (P < 0.05) of increasing phytase level for the AID of DM and a linear effect (P < 0.05) for the AID of CP. In the 21-d-old birds, increasing Ca levels resulted in a linear decrease (P < 0.05) in the AID of CP and P, and a quadratic decrease (P < 0.05) in the ATTR of CP. Increasing phytase levels linearly and quadratically (P < 0.05) improved the AID and ATTR of CP, P, and the ATTR of Ca. The analyzed phytase activity in the diets supplemented with phytase ranged from 1,520 to 7,661 FYT/kg. The digestible Ca equivalence for dietary phytase at 1,520 to 7,661 FYT/kg ranged from 1.55 to 2.02 g/kg in the 10-d-old birds fed for 3 d and from 0.52 to 0.64 g/kg in 21-d-old birds fed for 14 d. The results showed the reduction in Ca level that could be accommodated by phytase supplementation, which is markedly different between the younger and older birds. Feeding duration influenced the impact of phytase supplementation on Ca and P digestibility, with better efficacy of phytase observed in the 10-d-old birds fed for 3 d. Also, the results showed the extra-phosphoric effects of phytase on the utilization of other essential nutrients such as protein and Ca.

Impact of enzyme inclusion on the digestibility of protein, amino acids, calcium and phosphorus in growing pigs depending on meal size, frequency and sampling period

When digestibility trials are conducted, pigs are typically fed twice a day with a restricted amount of feed. These conditions are not representative of the feeding conditions in commercial farm. The present study aimed to determine the effects of meal size and frequency, xylanase and phytase inclusion as well as digesta sampling period, on the digestibility of protein, amino acids (AA), calcium (Ca) and phosphorus (P). Pigs (n = 6) were fitted with a T cannula, and each received all treatments following a 2 × 3 factorial arrangement in a 6 × 6 Latin square experimental design. The diets were supplemented or not with a combination of xylanase and phytase and divided into 3 feeding programs: one received 2 meals per day that met 3 times the maintenance energy requirement (2M), one received the same quantity of feed in 8 meals (8M), and another received an amount that supplied 5 times the maintenance energy requirements in 8 meals (8M+). Digesta was sampled from 0800 to 1200, 1200–1600, 1600–2000 and 0800–2000. The results indicated an improvement in the coefficient of apparent ileal digestibility of dry matter, crude protein, P, Ca, Val and Thr with enzyme inclusion in all meal distribution (enzyme effect, P < 0.05). Apparent ileal digestibility of Ca in the 0800–1200 period was reduced in 8M+ treatment compared to 2M and 8M whereas no difference was observed for meal size or frequency in 1200–1600 and 1600–2000 periods (Interaction meal × period, P = 0.017). A meal effect was observed for coefficient of apparent total tract digestibility of Ca (meal effect, P = 0.003) which was higher by 8% in pigs fed 8M compared to 8M+ (contrast 8M vs 8M+, P = 0.040). Saturation of the absorption processes may explain lower digestibility with 8M+ . Enzyme efficacy was not affected by meal size or frequency indicating minor modifications of digestive conditions. An 8-h sampling period would allow collection of a representative sample and avoid underestimating or overestimating digestibility of certain nutrients.

Supplementation of a Multi-Carbohydrase and Phytase Complex in Diets Regardless of Nutritional Levels, Improved Nutrients Digestibility, Growth Performance, and Bone Mineralization of Growing-Finishing Pigs.

This study was conducted to investigate the effects of dietary multi-enzyme (multi-carbohydrase and phytase complex, MCPC) supplementation on digestibility, growth performance, bone mineralization, and carcass yield and traits in growing-finishing pigs fed diets with adequate or deficient net energy (NE), amino acids (AA), calcium (Ca) and phosphorus (P) levels. A total of 576 crossbred [Duroc × (Landrace × Yorkshire)] barrows (~25 kg) were fed one of the six diets till live weight approached 130 kg. Basal diets included a positive control (PC), negative control 1 (NC1) and 2 (NC2), while another three diets were prepared by adding MCPC to the three basal diets. The final body weight was lower (p < 0.05) in NC2 than in NC1 and PC treatments, while overall feed intake and feed-gain ratio were higher (p < 0.05) in NC1 and NC2 than in PC treatment. The NC2 treatment showed lower (p < 0.05) carcass weight but higher (p < 0.05) lean meat percentage than the PC treatment. The apparent ileal digestibility (AID) of gross energy (GE), crude protein (CP) and AA was decreased (p < 0.05) or tended (p < 0.10) to decrease in NC1 and/or NC2 diets compared with a PC diet. MCPC supplementation improved (p < 0.05) AID of Ca, P and AA (Lys, Leu, Val, Phe, Gly, Tyr and Pro), apparent total-tract digestibility (ATTD) of GE, CP, bone strength, Ca, and P retention. In conclusion, MCPC supplementation improved nutrient digestibility, bone mineralization, and growth performance of fattening pigs, regardless of the nutritional level of the basal diet.

Determination of the standardized ileal digestible calcium requirement of male Arbor Acres Plus broilers from day 11 to 24 post-hatch

Male broilers (n = 576) were obtained and allocated to 96 cages with 6 birds per cage. From hatch to d 24, 16 randomly allocated cages were fed a nutrient adequate reference diet. The reference diet was formulated to contain 0.96 and 0.87% total Ca from hatch to d 10 and d 11 to 24, respectively. The remaining 80 cages were fed a nutrient adequate diet, formulated to contain 0.50% standardized ileal digestible (SID) Ca from hatch to d 10. On d 11, five diets containing 0.56, 0.46, 0.36, 0.26, or 0.16% SID Ca were randomly assigned to 16 cages per diet. Means were separated using polynomial contrasts and Dunnett's Multiple Comparison tests. From hatch to d 10, birds fed diets formulated to contain 0.50% SID Ca gained more (P < 0.05) compared with birds fed the reference diet. From d 11 to 24, there was no effect of diet on feed intake or BW gain. Birds fed 0.46 or 0.16% SID Ca were less (P < 0.05) efficient compared with birds fed the reference diet. Birds fed 0.26 or 0.36% SID Ca were more efficient compared with birds fed all other levels of SID Ca (quadratic, P < 0.05). Tibia ash percent was greatest in birds fed 0.56 or 0.46% SID Ca, decreased (quadratic, P < 0.05) as dietary SID Ca decreased and was lower (P < 0.001) in birds fed the 0.26 or 0.16% SID Ca diets compared with birds fed the reference diet. Apparent ileal digestibility (AID) of Ca or retention of P was greater (P < 0.05) in birds fed the diets formulated using SID Ca compared with birds fed the reference diet. Apparent P retention was greatest in birds fed 0.36% SID Ca (quadratic, P < 0.05). Regression equations developed using P retention, AID of Ca, and percent tibia ash estimated the SID Ca requirement of 11 to 24-d-old broilers was 0.380, 0.488, and 0.515%, respectively. This corresponds to a SID Ca to available P ratio of 0.86 to 1.17.

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

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

Influence of meat and bone meal, phytase, and antibiotics on broiler chickens challenged with subclinical necrotic enteritis: 1. growth performance, intestinal pH, apparent ileal digestibility, cecal microbiota, and tibial mineralization

This study investigated the influence of meat and bone meal (MBM), phytase, and antibiotics (AB) on the performance, intestinal pH, ileal digestibility, cecal microbiota, and tibial mineralization in Ross 308 broilers challenged with necrotic enteritis (NE). A total of 672-day-old male Ross 308 chicks were allocated to 8 treatments with 6 replicate pens, with 14 birds each. The study employed a 2 × 2 × 2 factorial arrangement of treatments: MBM (no or yes), AB (no or yes, zinc bacitracin + salinomycin), and phytase level (500 or 1,500 FTU/kg; both using 500 matrix recommendations). Diets were based on wheat–soybean meal–canola meal. All birds were challenged with Eimeria spp on day 9 and Clostridium perfringens (C. perfringens) strain EHE-NE18 on day 14 and day 15. On day 21 (postchallenge), birds fed MBM had reduced weight gain (WG; P < 0.05) relative to without MBM. A 2-way phytase × AB interaction for WG on day 14 (P < 0.001) and day 21 (P < 0.001) and feed conversion ratio on day 21 (P < 0.001) and day 42 (P < 0.01) indicated positive effects of high phytase on bird performance in the presence of AB. On day 42, a 3-way MBM × phytase × AB interaction (P < 0.01) was observed for WG, showing high phytase increased WG with AB, relative to the birds without AB in the presence of MBM. A 2-way MBM × phytase interaction (P < 0.01) was observed for apparent ileal digestibility of Ca and P on day 16, whereby there was a notable reduction in Ca and P digestibility in birds fed MBM-free diets and a low phytase level, but with the high phytase level, Ca and P digestibility was not influenced by MBM. In conclusion, in NE challenged birds, high phytase has a beneficial effect on leg health and mineral utilization to the extent that it can replace MBM and has beneficial effects on bird performance in the presence of AB.

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

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

Modification of a limestone solubility method and potential to correlate with in vivo limestone calcium digestibility

ABSTRACTWork was done to modify a limestone solubility assay to improve predictions of in vivo apparent ileal digestibility of Ca (AID Ca) in broilers and impacts on AID P. Limestones (LIME) were obtained from 3 commercial sources. LIME-1 (0.633 mm mean diameter, GMD); LIME-2 (ground sub-sample of LIME-1, GMD = 0.063 mm); LIME-3 (GMD = 0.326 mm), and LIME-4 (GMD = 0.831 mm). Solubility was determined at 5, 15, and 30 min of incubation using either a 0.2 N HCl (S1) or a pH 3 HCl (pH = 0.26) solution buffered with 3 M glycine (S2) to mimic gizzard and proventriculus pH. An AID trial was conducted with 320 Ross 708 male broilers. Treatments (Trt) were no added LIME, or added LIME-1, 2, 3, and 4 to achieve 0.67% Ca, to a basal diet (no added inorganic P, 0.07% Ca) with or without 1,000 U phytase/kg (36 h, 23 to 24 D of age, n = 8, 4 birds/n). Distal ileal digesta was collected from all birds and pooled by pen. Irrespective of interaction, LIME solubilized quicker and more completely with S1 vs. S2 at all time points (P < 0.05). LIME-2 solubilized the quickest, while LIME-3 had the lowest solubility through all incubation times (P < 0.05). The AID Ca was 66.30, 47.46, 19.93, and 66.33% for LIME-1, 2, 3, and 4, respectively (0 U/kg, P < 0.05). Phytase inclusion increased AID Ca by 15% on average (P < 0.05). The AID P dig was highest in no LIME added diet (74.91%) and adding LIME reduced (P < 0.05) AID P to 23.14, 12.78, 65.47, and 37.40%, for LIME-1, 2, 3, and 4, respectively in the absence of phytase. Regression showed that GMD, 15- and 30-min solubility were critical for AID Ca (R2 between 0.978 and 0.988). In conclusion, the solubility dynamics including speed and extend of solubilization, rather than a single timepoint, yield better predictions for in vivo Ca digestibility of LIME.

176 Whole-grain fiber composition modifies phosphorus digestibility in grower pigs

Abstract Increased fermentable carbohydrates in cereal grains due to more amylose in starch or β-glucan in fiber may increase endogenous losses including for P, and thereby reduce apparent total tract digestibility (ATTD) of P. This study assessed effects of barley cultivars varying in chemical composition on apparent ileal digestibility (AID) and ATTD of P and Ca, and standardized total tract digestibility (STTD) of P compared with wheat. In a 6 (period) × 5 (diet) Youden square, 7 ileal-cannulated barrows (27.7 kg initial BW) were fed diets containing 80% of 1 of 5 grains differing in amylose, β-glucan, and fiber: 1) high-fermentable, high-β-glucan, hull-less barley (HFB); 2) high-fermentable, high-amylose, hull-less barley (HFA); 3) moderate-fermentable, hull-less barley (MFB); 4) low-fermentable, hulled barley (LFB); and 5) low-fermentable, hard red spring wheat (LFW). Diet STTD of P was calculated by correcting ATTD for the basal endogenous P loss using a constant value of 190 mg P/kg DM intake. Whole grains contained between 8.5 to 16.3 µmol/g DM phytate (any salt of myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate); InsP6) and 1.6 to 3.0 g/kg DM InsP6-P. Data were analyzed using a mixed model with diet as fixed effect, and pig and period as random effects. On DM basis (g/kg), diets contained 131 to 286 g neutral detergent fiber, 8.8 to 85.4 g β-glucan, and 8.1 to 8.9 g total P. The MFB, LFB, and LFW had greater (P &lt; 0.001) AID of P than HFB and HFA, and MFB had greater (P &lt; 0.05) ATTD or STTD of P than HFB. The LFW had greater (P &lt; 0.05) ATTD of Ca than LFB, whereas diet did not affect (P &gt; 0.05) AID of Ca. In conclusion, whole grains high in fermentable fiber, e.g. β-glucans, in specific hull-less and hulled barley cultivars decreased diet digestibility of P and Ca.

True ileal digestibility of calcium in limestone and dicalcium phosphate are additive in diets of broiler chickens

The experiment was conducted to test if the true ileal digestibility (TID) of Ca in limestone and dicalcium phosphate (DCP) are additive in mixed diets for Ross 708 broiler chickens from day 22 to 27 post-hatching. The birds were fed a standard broiler starter diet from day 1 to 22 post-hatching. A total of 504 birds were grouped by BW into 8 blocks of 9 cages with 7 birds per cage and assigned to 9 dietary treatments in a 3 × 3 factorial arrangement of 3 Ca sources including limestone, DCP, and their mixture at a ratio of 1:1, and 3 dietary Ca concentrations at 3.3, 4.3, and 5.3g/kg. Potassium phosphate was added to adjust the dietary P concentration and maintain a 1.1:1 total Ca:non-phytate P ratio. The results showed that the Ca intake, ileal Ca digested, and Ca retained linearly increased as the Ca concentration increased (P < 0.001). No Ca concentration effect was observed on apparent ileal digestibility of Ca (P = 0.13). By regressing digested Ca per bird against Ca intake per bird, the TID of Ca was determined at 63.7, 67.1, and 67.8% for limestone, DCP, and their mixture, respectively. The expected TID for Ca in limestone and DCP mixture was predicted to be 65.1% based upon the Ca contribution coefficient calculated to be 0.59 for limestone and 0.41 for DCP. The predicted TID of Ca (65.1%) in the mixture was not different (P = 0.63) from the determined TID of Ca (67.8%). In conclusion, the TID of Ca in limestone and DCP are additive in semi-purified diets for chickens.

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).

A new phytase continuously hydrolyzes phytate and improves amino acid digestibility and mineral balance in growing pigs fed phosphorous-deficient diet.

Ten ileal T-cannulated pigs (19.26 ± 1.06 kg) were used to evaluate the effects of a novel phytase on apparent ileal digestibility (AID) of AA and apparent total tract digestibility (ATTD) and hindgut disappearance of DM, GE, CP, crude fiber, NDF, and ADF as well as minerals balance. Pigs were fed in a duplicated 5 × 4 incomplete Latin square design (5 diets with 4 periods). Each period consisted of a 5-d adjustment period followed by a 3-d total collection of feces and urine and then a 2-d collection of ileal digesta. The 5 diets included a P-deficient basal diet (0.43% Ca and 0.38% total P) that was supplemented with 0 (negative control [NC]), 500, 1,000, or 20,000 phytase units (FTU)/kg phytase and a positive control (PC) diet that was P adequate (0.64% Ca and 0.52% total P). The addition of phytase to the NC diet improved ( < 0.05) AID of phytate from 11.1 to 62.8, 70.6, and 90.5% at the inclusion rates of 500, 1,000, and 20,000 FTU/kg, respectively. In general, phytase supplementation at a dose of 20,000 FTU/kg further increased ( < 0.05) AID of Ca, total P, and phytate and reduced ( < 0.05) the ileal phytate concentration compared with diets with 500 or 1,000 FTU/kg phytase. Pigs fed the diet with 20,000 FTU/kg phytase but not diets with 500 and 1,000 FTU/kg phytase showed improved ( < 0.05) ATTD of CP and AID of DM, GE, CP, Leu, Lys, Thr, Val, Asp, and Ser compared with pigs fed the PC or NC diet. However, hindgut disappearance of crude fiber and NDF ( < 0.05) were reduced in pigs fed the diet with 20,000 FTU/kg phytase compared with pigs fed the PC or NC diet. Pigs fed diets with 500 or 1,000 FTU/kg phytase had greater ATTD and retention of Ca and P than pigs fed the NC diet but less compared with pigs fed the diet with 20,000 FTU/kg phytase. Supplementation of 20,000 FTU/kg phytase to the NC diet improved ( < 0.05) digestibility of Na, Mn, and Zn as well as retention (%) of Zn. Increasing phytase supplementation doses from 0 to 1,000 FTU/kg linearly improved ( < 0.05) retention of Mg; meanwhile, digestibility of Mg and Mn and AID of Thr showed a linear increase trend ( = 0.084). In conclusion, supplementation of the novel phytase at doses up to 20,000 FTU/kg hydrolyzed most of the phytate (90%) and consequently further improved mineral and protein utilization.

Apparent ileal digestibility of calcium in limestone for broiler chickens

The objective of the study that is presented herein was to determine the apparent ileal calcium (Ca) digestibility of limestone for broiler chickens as influenced by limestone source and dietary phosphorus (P) concentration. Limestone from three commercial sources (coded as LM-1, LM-2 and LM-3) were obtained, ground to pass through a 0.2mm sieve and analysed for mineral composition and in vitro solubility. Analysed Ca concentration and in vitro solubility coefficient of LM-1, LM-2 and LM-3 were 410, 390 and 420g/kg, and 0.28, 0.29 and 0.27, respectively. Two experimental diets, containing 9g/kg Ca, were developed from each limestone source with 0 and 4.5g/kg dietary P. Titanium dioxide was incorporated as an indigestible marker. Each experimental diet was then randomly allotted to six replicate cages (eight birds per cage) and fed from day 21 to 24 post-hatch. Apparent ileal digestibility of Ca was calculated using the indicator method. Apparent ileal Ca digestibility coefficients of LM-1, LM-2 and LM-3 were determined to be 0.58, 0.61 and 0.54, respectively. Calcium digestibility of LM-3 was lower (P<0.05) than LM-2 but similar (P>0.05) to LM-1. There was no difference (P>0.05) between the Ca digestibility of LM-1 and LM-2. Increasing the dietary P concentration from 0 to 4.5g/kg in assay diets increased (P<0.05) the average Ca digestibility from 0.56 to 0.60.

Measurement of true ileal calcium digestibility in meat and bone meal for broiler chickens using the direct method

The objective of the study that is presented herein was to determine the true ileal calcium (Ca) digestibility in meat and bone meal (MBM) for broiler chickens using the direct method. Four MBM samples (coded as MBM-1, MBM-2, MBM-3 and MBM-4) were obtained and analyzed for nutrient composition, particle size distribution and bone to soft tissue ratio. The Ca concentrations of MBM-1, MBM-2, MBM-3 and MBM-4 were determined to be 71, 118, 114 and 81 g/kg, respectively. The corresponding geometric mean particle diameters and bone to soft tissue ratios were 0.866, 0.622, 0.875 and 0.781 mm, and 1:1.49, 1:0.98, 1:0.92 and 1:1.35, respectively. Five experimental diets, including four diets with similar Ca concentration (8.3 g/kg) from each MBM and a Ca and phosphorus-free diet, were developed. Meat and bone meal served as the sole source of Ca in the MBM diets. Titanium dioxide (3 g/kg) was incorporated in all diets as an indigestible marker. Each experimental diet was randomly allotted to six replicate cages (eight birds per cage) and offered from d 28 to 31 post-hatch. Apparent ileal Ca digestibility was calculated by the indicator method and corrected for ileal endogenous Ca losses to determine the true ileal Ca digestibility. Ileal endogenous Ca losses were determined to be 88 mg/kg dry matter intake. True ileal Ca digestibility coefficients of MBM-1, MBM-2, MBM-3 and MBM-4 were determined to be 0.560, 0.446, 0.517 and 0.413, respectively. True Ca digestibility of MBM-1 was higher (P < 0.05) than MBM-2 and MBM-4 but similar (P > 0.05) to that of MBM-3. True Ca digestibility of MBM-2 was similar (P > 0.05) to MBM-3 and MBM-4, while that of MBM-3 was higher (P < 0.05) than MBM-4. These results demonstrated that the direct method can be used for the determination of true Ca digestibility in feed ingredients and that Ca in MBM is not highly available as often assumed. The variability in true Ca digestibility of MBM samples could not be attributed to Ca content, percentage bones or particle size.

Evaluation of a highly soluble calcium source and phytase in the diets of broiler chickens

An experiment was conducted to evaluate the influence of a highly soluble Ca (HSC) source on performance, bone ash and mineralization, and apparent ileal digestibility of Ca, P, N, and energy in Ross 708 broiler chickens. Dietary Ca was supplied by the HSC source and monocalcium phosphate to provide 4 levels of Ca (0.45, 0.60, 0.75, or 0.90%). Available P (aP) was maintained at 0.32% in all the diets. Each diet was supplemented with 0, 500, or 2,500 U/kg of phytase as a 4 × 3 factorial. An additional diet was formulated using limestone to contain 0.90% Ca and 0.45% aP as a positive control (PC). Diets were fed to 7 replicate cages of 8 birds per cage from d 0 to 21 posthatch. Feed intake (FI) was linearly (P ≤ 0.05) reduced, and BW gain was quadratically (P ≤ 0.05) reduced as Ca from HSC increased from 0.45 to 0.90%. Phytase supplementation linearly (P ≤ 0.05) increased FI and BW gain and improved feed conversion ratio. Tibia ash and P weights were lower in birds fed 0.90% Ca from HSC compared with broilers fed 0.90% Ca from limestone. Phytase supplementation increased tibia ash and P weights in broilers fed 0.60, 0.75, or 0.90% HSC (Ca level × phytase P ≤ 0.05). Phytase supplementation linearly (P ≤ 0.05) increased tibia Ca weight. Reducing HSC from 0.90 to 0.45% or increasing phytase supplementation linearly (P ≤ 0.05) improved ileal P digestibility. Ileal Ca digestibility increased linearly only in broilers fed 0.45% Ca from HSC as phytase supplementation increased (Ca level × phytase P ≤ 0.05). Nitrogen or energy digestibility were quadratically (P ≤ 0.05) influenced as HSC or phytase increased. In conclusion, feeding HSC with phytase allowed for reductions in dietary Ca while maintaining broiler performance and bone ash. In addition, P digestibility and P in the bones were increased in broilers fed reduced dietary Ca in the presence of phytase.

Influence of limestone and phytase on broiler performance, gastrointestinal pH, and apparent ileal nutrient digestibility

An experiment was conducted to determine the influence of 2 levels of dietary Ca from limestone and 3 levels of phytase on broiler performance, bone ash, gastrointestinal pH, and apparent ileal digestibility (AID) of Ca, P, and amino acids. Cobb 500 broilers (n = 576) were allowed access to one of 6 corn-soy diets from 0 to 16 d. Experimental diets contained 1.03% or 0.64% Ca from limestone and 0.61% total P. Each diet was supplemented with 0, 500, or 5,000 FTU/kg of phytase to create a 2 × 3 factorial experiment. Broiler feed intake (FI) and BW gain were not affected by dietary Ca or phytase. Feed conversion ratio was improved (P < 0.05) as dietary phytase increased (1.36, 1.34, and 1.31, respectively). Tibia ash percent was reduced (P < 0.05) from 41.4 to 40.0% as dietary Ca decreased but increased with phytase addition (P < 0.05). Gizzard and ileal pH were reduced (P < 0.05) in broilers fed 0.64% Ca compared with broilers fed 1.03% Ca. Phytase at 5,000 FTU/kg increased (P < 0.05) pH in the gizzard, duodenum, jejunum, and ileum. Apparent ileal P digestibility was increased (P < 0.05) in broilers fed 0.64% Ca compared with broilers fed 1.03% Ca (0.68 vs. 0.73, respectively). Apparent ileal Ca digestibility was increased (P < 0.05) in broilers fed 1.03% Ca compared with broilers fed 0.64% Ca (0.67 vs. 0.53, respectively). Phytase improved AID of CP in broilers fed 1.0% Ca but did not have an effect on AID of CP in broilers fed 0.64% Ca, which resulted in a Ca × phytase interaction (P < 0.05). In conclusion, high dietary Ca increased pH in gizzard and ileum and interfered with the AID of P and CP. The interactions between Ca and phytase in the gastrointestinal tract are complex, and feeding phytase at doses above industry recommendations may allow for reduced-Ca diets while maintaining broiler performance, bone ash, and improving amino acid digestibility.

Effect of phytase supplementation with two levels of phosphorus diets on ileal and faecal digestibilities of nutrients and phosphorus, calcium, nitrogen and energy balances in growing pigs

AbstractThe experiment was conducted to assess the effects of phytase supplementation to diets with two levels of phosphorus (P) on ileal and faecal digestibility of nutrients and phosphorus, calcium, nitrogen and energy balances in growing pigs. Fifteen Landrace × Large White × Chinese Black barrows, with an initial live weight of 22·2 kg fitted with a simple T-cannula at the distal ileum, were randomly allocated to one of the five diet treatments, according to a of cross-over design with two periods. The basal diet was typical of southern Asia with maize/rice and rapeseed/cottonseed meals. A normal (NP, supplemented with 4·8 g/kg of CaHPO4) and a low-P diet (LP, not supplemented with CaHPO4) were formulated. Both of the diets were supplemented with and without Natuphos® Phytase (500 phytase units (FTU) per kg diet). An enzyme hydrolysed casein (EHC) diet (diet 5) was also formulated to determine the flow of the ileal endogenous amino acids (AA). The results showed that both the higher level P treatment and phytase supplementation increased (P &lt; 0·05) the apparent ileal digestibility (AID) of dry matter (DM), organic matter (OM), crude protein (CP) and energy. Phytase supplementation also increased (P &lt; 0·05) the AID of Ca and P. Pigs given the higher level of P or the phytase diet increased apparent faecal digestibility (AFD) of DM, OM and energy. Phytase supplementation reduced (P &lt; 0·01) faecal Ca output and increased (P &lt; 0·05) proportional Ca retention. The higher level of P increased (P &lt; 0·001) total P intake and P retention (P &lt; 0·05) but did not affect the proportion of P retained (P &gt; 0·05). Phytase supplementation did not affect P balance (P &gt; 0·05). Pigs given the higher level P or the phytase diet had reduced (P &lt; 0·05) faecal energy concentration, although there was no affect on urine energy output, digestible energy (DE) and metabolizable energy (ME). However, there were P × phytase effects on DE and ME (P &lt; 0·05). There were no P × phytase effects (P &gt; 0·05) on AID of AA except with isoleucine (P &lt; 0·01). Phytase supplementation increased (P &lt; 0·05) AID of histidine, isoleucine, threonine and glutamine and there was a numeric increase in AID for most of the other AA. There was P × phytase effect on AFD of histidine (P &lt; 0·05), isoleucine (P &lt; 0·05), methionine (P &lt; 0·05) and threonine (P &lt; 0·01). Phytase supplementation increased the AFD of isoleucine (P &lt; 0·05), threonine (P &lt; 0·01) and tended to increase AFD of tyrosine (P &lt; 0·05). The level of MCP affected the AFD of lysine (P &lt; 0·01), threonine (P &lt; 0·05), aspartic acid (P &lt; 0·05). Phytase supplementation increased true ileal digestibility of histidine (P &lt; 0·05), isoleucine (P &lt; 0·001), threonine (P = 0·001), glutamine (P &lt; 0·01), respectively. These results indicate that phytase used in the present study was able to improve the utilization of DM, OM, CP, Ca, P, energy and amino acid in a maize/rice and rapeseed/cottonseed meal based diet and reduce total output of them in manure.