bluuebunny/crossref_metadata_2025_split huggingface dataset:
261 Relationship between dietary calcium and available phosphorus in growing pigs
Authors: McKibben Grace C , Sparks Chris , Miller Kayla A , Due Elizabeth M , Nisley Mitchell J , Gabler Nicholas K 
Published: May 2024

Abstract
The amount of and relationship between dietary total calcium (tCa) and available phosphorus (avP) are critical for lean and bone growth in pigs. Our objective was to evaluate the relationship between tCa and avP in nursery-grower pigs. Mixed sex pigs [n = 117; initial body weight (BW) = 11 ± 0.17 kg] were blocked by BW to individual pens and assigned to 1 of 18 dietary treatments (n = 6 to 7 pigs/trt). Treatments were divided into 4 titrations containing 5 treatments each. Each titration had the same tCa:avP of 1.52, 1.77, 2.12, 2.64, and 3.50. In titration 1(T1), tCa was set at NRC recommendation of 0.68% and avP ranged from 0.46 to 0.20%. Titration 2(T2), tCa was set at 14% below NRC recommendation at 0.56% and avP ranged from 0.38 to 0.16%. Titration 3(T3), avP was set at NRC recommendation of 0.33% and tCa ranged from 0.49 to 1.12%. In titration 4(T4), avP was set at 0.26% with tCa ranging from 0.39 to 0.90%. Pig BW and feed disappearance were recorded at the beginning and the end to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency gain to feed ratio (G:F) performance parameters over the 40-d study duration. Thereafter, whole body, femur, and 3rd metatarsal bone mineral density (BMD) and contents (BMC) were measured using a dual-energy X-ray absorptiometry (DXA). Within each titration, data were analyzed with pig as the experimental unit, random effect of block and the fixed effect of diet. In T1, performance parameters did not differ (P &gt; 0.10). However, body BMD decreased (0.843, 0.841, 0.804, 0.706, and 0.585 g/cm2) as tCa:avP increased (P &lt; 0.001). In T2, as tCa:avP increased, ADG decreased (0.85, 0.85, 0.77, 0.73, and 0.67 kg/d; P &lt; 0.001). Similarly, whole body BMD decreased as tCa:avP increased (0.800, 0.803, 0.668, 0.616, and 0.558 g/cm2; P &lt; 0.001). ADG, ADFI and whole and individual BMC did not differ in T3 and T4. Consequentially, body BMD ranged from 0.756 to 0.808 g/cm2 in T3 and 0.656 to 0.703 g/cm2 in T4. Breakpoint analysis reported tCa:avP of 2.321 and 1.849 or less was optimal for BMD in T1 and T2, respectively. No optimal breakpoints could be determined for whole BMD within T3 and T4. Breakpoint analysis for ADG reported tCa:avP of 2.311 and 2.341 or less was optimal in T2 and T3, respectively. No optimal breakpoints could be determined for ADG within T1 and T4.
257 Estimating bone mineral replenishment following phosphorus deficiency in growing pigs
Authors: McKibben Grace C , Cordero Gustavo , Gomes Gilson A , Becker Spenser , Wilcock Pete , Gabler Nicholas K 
Published: May 2024

Abstract
Available phosphorus (avP) is essential for bone health and strength in growing pigs. Our objective was to evaluate growth performance and replenishment of bone mineral in avP deficient pigs when fed diets adequate in avP. Over a 42-d test period, mixed sex pigs [n = 48; initial body weight (BW) = 13.1 ± 0.7 kg], were randomly assigned to one of three dietary treatments consisting of two experimental periods. In period 1(28 d), 8 pens/trt (2 pigs/pen) were fed diets formulated to 0.36, 0.17 and 0.08% avP and at a total calcium to avP ratio of 2.91, 3.15 or 6.40, respectively, representing adequate, marginally deficient, or deficient avP. In period 2 (14 d), marginally deficient and deficient pigs were then fed diets formulated to be above requirement at 0.54% avP and a 2.19 Ca:avP, while the adequate pigs staying on the same period 1 diet (n = 8 pens/trt). Pig BW and pen feed disappearance were recorded during each phase to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency gain to feed (G:F). At the end of each period, 1 pig per pen was removed to assess whole body, femur, and 3rd metatarsal bone mineral content (BMC) and bone mineral density (BMD) via dual-energy X-ray absorptiometry (DXA). All data were analyzed with pen as the experimental unit and the fixed effect of diet within each period. At the end of period 1, adequate avP and marginally deficient fed pigs were heavier than the deficient avP fed pigs (41.9 and 41.2 vs 33.4 kg, respectively, P &lt; 0.001). Consequently, ADG and ADFI were significantly reduced as avP decreased (P &lt; 0.001). Compared with the adequate avP pigs, whole body BMD was reduced by 22% and 65% in marginal and deficient avP pigs (P &lt; 0.001), respectively. At the end of period 2, adequate, marginal, and deficient avP pigs weighed 53.4, 53.2 vs 43.1 kg (P &lt; 0.001), respectively. Within period 2, ADG, ADFI, and G:F did not differ. However, adequate avP fed pigs continued to have a greater body BMD compared with marginal and deficient avP pigs (0.928, 0.850, and 0.732 g/cm2; P &lt; 0.001), respectively. Whole body BMD and BMC increased from period 1 to peiod 2, resulting in period 2 whole body BMC accretion rates of 2.31, 23.28, and 9.30 g/d (P &lt; 0.007) for deficient, marginal, and adequate diets, respectively. In conclusion, pigs fed marginally deficient avP diets reduced body BMD while pigs fed deficient avP diets reduced body BMD and performance. Following this period of deficiency, marginal deficient avP pigs recovered growth and BMC within 14 d when fed increased dietary avP. However, compared with adequate avP fed pigs, the deficient pigs only partially recovered BMC and BW within the 14-d replenishment period.
259 Effect of very low calcium diet supplemented with microbial phytase in post-weaning piglets
Authors: Montminy Marie-Pierre Létourneau , De Oliveira Marllon 
Published: May 2024

Abstract
Young piglets have an immature intestine that provides limited gastric acidity to digest nutrients compared with later stages of growth. Food has the intrinsic capacity to modify gastric acidity, particularly in relation to their concentrations of limestone, the ingredient with the greatest capacity to bind to acid. An experiment was conducted to evaluate the impacts of reducing dietary calcium (Ca) by reducing calcium supplementation immediately after weaning; compared with the recommendations of the NRC (2012), in association with phytase supplementation. The treatments were distributed during 3 phases [Phase 1 (P1, d 0-9), 2 (P2, d 10-16) and 3 (P3, d 17-35)]. Treatments were: 1) a diet low Ca that did not contained limestone during phase 1 (LowCa), P1 to P3 respectively, 0.51-0.60-0.65 % Ca and 0.48-0.43-0.38 % standardized ileal digestible P (STTD P), 2), diet 1 with microbial phytase (LowCa+PhytM); P1 to P3 respectively, 0.51-0.60-0.65 % Ca and 0.48-0.43-0.38% STTD P with 750 FTU phytase, and 3) a diet fulfilling requirement (NormalCa+PhytM) P1 to P3 respectively, 0.85-0.80-0.70 % Ca and 0.48-0.43-0.38 % STTD P with 750 FTU phytase. Piglets (n = 120) were allocated to 6 pens of 5 piglets per treatment in function of initial body weight (BW; 6.12 ± 0.028 kg). On d 0, 15 and 36, dual X-ray (DXA) bone densitometry was used to measure body fat, lean and mineral content (BMC) compositions using 8 piglets per treatment. At the end of phase 1 (d 9) a blood sample was collected. Data were analyzed using the SAS MIXED procedure with Tukey’s test to compare means. No differences were observed in growth performance or DXA measurements during the first phase. On d 9, LowCa piglets showed signs of hypocalcaemia with reduced plasma Ca (P = 0.03), increased plasma P (P = 0.02) and a lower Ca:P ratio in plasma (P = 0.04). From d 9-15, piglets that had received LowCa+PhytM showed greater average daily gain (ADG; P = 0.002) while other criteria did not differ between treatments. On d 15, the body composition evaluated by DXA showed no difference among dietary treatments. During phase 3, final BW and average daily feed intake were not modified by dietary treatments, while average daily gain and feed efficiency were greater in LowCa than in NormalCa+PhytM (+7.3 and 6.7%, respectively), and LowCa+PhytM was intermediate. Body composition on d 35 showed no difference among treatments while a tendency (P = 0.095) for greater BMC deposition (g/d) in LowCa in comparison with NormalCa+PhytM (+1.3 %). The implemented LowCa strategy resulted in momentary hypocalcemia which probably activated homeostatic mechanisms allowing piglets to be more efficient in using minerals and possibly other nutrients leading to better growth performance, without impact on bone mineralization.
264 Effects of increasing available phosphorus for 6 to 16 kg pigs fed diets containing phytase
Authors: Cemin Henrique S , Hart Morgan , Hansen Sharlie A , Soto Jose A , Hansen Ernie L 
Published: May 2024

Abstract
An experiment was conducted to determine the effects of increasing available phosphorus (aP) levels on growth performance of nursery pigs under commercial conditions. A total of 2,340 pigs [PIC 337 × 1050, initial body weight (BW) = 6.0 kg], placed in pens with 35 or 36 pigs, were used in a 39-d trial. Treatments were arranged in a dose titration with six levels of aP and 11 replicates per treatment. The aP levels were 0.33, 0.39, 0.46, 0.52, 0.59, and 0.65%. Two basal diets with the least and greatest aP levels were manufactured in meal form and blended at the farm to create the intermediate levels. Phytase [Allzyme Spectrum Swine (Alltech, Nicholasville, KY)] was included in the experimental diets at superdose levels with an estimated 0.15% aP release. Calcium levels were adjusted in each diet to maintain a constant 1.20 Ca:P. The experimental diets were fed from d 0 to 21 and a common corn-soybean meal-based diet with adequate aP level was fed from d 21 to 39. Data were analyzed with the MIXED procedure in SAS in a randomized complete block design with pen serving as the experimental unit and initial BW as the blocking factor. From d 0 to 21, pigs fed increasing levels of aP had improved (quadratic, P ≤ 0.024) average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency [gain to feed ratio (G:F); Table 1]. For ADG and G:F, the quadratic polynomial resulted in the best fit predicting 100% of maximum response at 0.50 and 0.52% aP for ADG and G:F, respectively. Similar improvements (quadratic, P ≤ 0.049) were also observed in the overall period (d 0 to 39). From d 21 to 39, while pigs were fed a common diet, there was no evidence (P &gt; 0.05) for differences in growth performance. There was no evidence (P &gt; 0.05) for differences in mortality rate. However, there was a quadratic response (P = 0.008) in removal rate, with declining rates up to 0.59% aP. In summary, growth performance of 6 to 16 kg pigs was maximized with 0.50 to 0.52% aP with further improvements in removal rate observed with greater aP levels.
263 Effects of source of calcium carbonate and microbial phytase on standardized total tract digestibility of calcium by growing pigs
Authors: Nelson Megan E , Lee Su A , Walk Carrie , Stein Hans H 
Published: May 2024

Abstract
The objective of this experiment was to test the hypothesis that there are differences in the standardized total tract digestibility (STTD) of Ca and in response to microbial phytase among sources of calcium carbonate obtained from different regions of the world. Barrows [n = 320; average body weight (BW) = 17.47 kg; SD = 1.28] were allotted to 40 diets using a completely randomized block design with eight blocks of 40 pigs for a total of eight replicate pigs per diet. All diets were based on corn and potato protein concentrate. Twenty sources of calcium carbonate were obtained from different regions of the world, including the United States, Europe, Asia, and South Africa. Each source of calcium carbonate was used in two diets, one diet without microbial phytase and one diet that contained 1,000 phytase units/kg diet. Pigs were housed individually in metabolism crates. Pigs were provided feed at 3.0 times the maintenance requirement for energy. Feces were collected for 4 d following the adaptation period after 5 d of adaptation. Fecal samples were dried, ground, and analyzed for Ca to calculate the digestibility. The initial statistical model included calcium carbonate source, phytase, and the Ca-source × phytase interaction as fixed effects; however, no interactions between Ca source and phytase were observed. Therefore, the final statistical model included only Ca source and phytase as fixed effects. A second analysis was performed to compare the digestibility of Ca in calcium carbonate obtained from different regions of the world (i.e., Europe, Asia, the United States, and South Africa). In this model region, phytase, and the region × phytase interaction were fixed effects. However, no interactions between region and phytase were observed and therefore, the final statistical model included only region and phytase as fixed effects. Concentrations of Ca in the 20 sources of calcium carbonate ranged from 32.1 to 40.9% (Table 1). Differences in the STTD of Ca were observed among pigs fed diets containing different sources of calcium carbonate (P &lt; 0.001). Pigs fed diets containing 1,000 units of phytase had greater (P &lt; 0.001) STTD of Ca compared with pigs fed diets containing no phytase. The STTD of Ca in calcium carbonate from the United States was less (P &lt; 0.001) than in calcium carbonate from Europe, Asia, or South Africa. In conclusion, the use of microbial phytase increases the STTD of Ca in calcium carbonate, but the STTD of Ca varies among different sources and among sources from different regions. Therefore, consideration should be given to differences in analyzed concentrations of Ca, values for STTD of Ca, and response to microbial phytase among different sources of Ca carbonate to ensure Ca is not being oversupplied when formulating diets.
255 Anchor Talk: Consider intrinsic factors that regulate homeostasis to optimize sustainability of mineral supplements for swine
Authors: Crenshaw Thomas D , Grez-Capdeville Mariola , Amundon Laura A , Kokinos Brittney P 
Published: May 2024

Abstract
Decades of research has focused on methodologies to improve the efficiency of mineral use while assuring sufficient intake to meet animal well-being and production needs. A primary focus of these efforts is P, as P is the third most expensive category of nutrients supplemented in swine diets. Bioavailability of P is more variable than other nutrients in feed ingredients commonly fed to swine. Due to complexities involved in assessments of P bioavailability efforts shifted to defining P digestibilities for each ingredient. Efforts to refine P digestibilities, based on intake and fecal excretion, even with corrections for endogenous losses, have failed to provide a constant coefficient for feed ingredients that can be included in diet formulations, as the digestibility estimates vary with animal age, production phases and inclusion of enzymes such as phytase. An under-appreciated contribution to inaccuracies of digestible P relates to intrinsic regulation of Ca and P homeostasis by the animal. Regulation of Ca and P homeostasis by PTH and 1,25(OH)2D3, must now include a third mineralotropic hormone, FGF23. Applying insights for intrinsic roles of FGF23 will allow more efficient use of nutrients, especially P and vitamin D. FGF23 regulates activation of vitamin D and controls renal P excretion. Over-supplementation of P signals osteocytes (bone cells embedded in a mineralized matrix) to release intact FGF23 which targets the kidney to block reabsorption of P for maintenance of soft tissue homeostasis, resulting in an inefficient use of dietary P. Intact FGF23 also inhibits hydroxylation of 25-OH D3 to form 1,25(OH)2D3. These endocrine pathways illustrate major roles provided by kidneys and bone to allow adaptation to variable Ca and P inputs, thus maintaining homeostasis. Recent efforts to assess P requirements of sows during gestation and lactation illustrate the sensitivity of using renal excretion of Ca and P to assess requirements. Based on 24-h collections, urine Ca:P ratios &gt; 1.5 were consistent with deficient P intake, ratios from 0.5 to 1.5 reflected P adequacy, and ratios &lt; 0.5 indicated excessive P intake. As a practical method, spot urine samples collected at variable times throughout the day reliably predicted Ca:P ratios in 24-h urine collections. Thus, a simplified approach using Ca to P ratio in spot urine samples can be used to assess P intake adequacy. This practical approach can be applied in commercial sow herd to allow herd-based assessment of P status. In conclusion, within herd assessments, based on urine Ca:P ratios, can be used to determine if P supplements are deficient, adequate, and excessive. As such, significant progress can be made to provide a balance between the need to adequately meet animal need with efforts to minimize negative environmental impacts from over-supplementation of P.
258 Nutritional strategies allowing inorganic phosphates reduction in maintaining maximum growth performance and bone mineralization in piglets
Authors: Rousseau Xavière , Bréhélin Tristan , Rougier-Borne Cécile , Cordero Gustavo 
Published: May 2024

Abstract
Phosphorus (P) is an essential component for optimal maintenance of growth and bone mineralization but its inclusion in animal feed is a core concern for economic and environmental concerns in ensuring sustainability of this resource. This study aimed to test impacts of different nutritional strategies such as dietary calcium (Ca) reduction and phytase superdosing for piglets fed without inorganic phosphate. A total of 147 piglets Piétrain*(Large White*Landrace) were divided among 5 experimental diets. Three levels of digestible P were tested (0.21%, 0.27%, 0.33%) by adding monocalcium phosphate (MCP) from 1) a negative control diet (NC) without MCP, 2) a diet with 0.3 % MCP (NC+0.3 % MCP), or 3) a diet with 0.6 % MCP (NC+0.6 % MCP). Those three diets contained 250 FTU/kg of phytase and a minimum amount of phytate set at 0.27%. All dietary treatments were formulated following a constant Ca:digestible P ratio at 2.1. The other two diets were formulated with two phytase’ doses added on top of the NC diet 4) 2,000 FTU/kg (NC+2000 phy) or 5) 3,000 FTU/kg (NC+3000 phy). Piglets were weighed individually at 42, 55 and 69 d of age, and feed intake per phase was recorded per pen. Average daily gain (ADG), daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated. At the end of the experiment, right metacarpal was removed from 12 animals per treatment to analyze bone mineralization. Data were submitted to an ANOVA including effects of dietary treatments and body weight at start of the trial using JMP 16.2.0. Differences among means were separated by a Student’s test and significance accepted at P &lt; 0.05. Liveability % was not different between treatments. The reduction of Ca and digestible P in NC did not affect growth performance (P &gt; 0.05) but reduced bone ash % compared with PC (P &lt; 0.05, 30.4 % vs 34.6 %, respectively). Phytase supplementation at 2,000 and 3,000 FTU/kg improved body weight gain (28.8 kg for animals fed NC vs 30.0 kg for NC+2000 phy vs 30.2k g for NC+3000 phy, P &lt; 0.05), feed efficiency (1.60 vs 1.50 for NC and NC + 3000 phy, respectively; P &lt; 0.05) and bone mineralization (P &lt; 0.05). This experiment confirms the benefit of reducing the Ca and concomitantly P levels in piglet feed without impairing growth performance by optimal use of phytase that also provides the ability to overcome dependence on inorganic phosphates.
260 Effect of different doses of phytase (HiPhorius) and two primary calcium sources on nutrient digestibility, retention and blood parameters in weaned piglets
Authors: Guan Xiaonan , Lagos Vanessa , Smith Adam , Walk Carrie , Zhai Heng-Xiao , Molist Francesc 
Published: May 2024

Abstract
An 18-d study evaluated the effect of increasing phytase levels in diets with limestone or Ca-formate on Ca and P digestibility, P retention, and blood inositol, Ca, and P in weaned piglets. At weaning, male piglets [n = 60; 29.8 ± 1.10 d of age; initial body weight (BW) = 8.8 ± 0.31 kg) were randomly allocated to ten diets formulated as a 2 × 5 factorial design with 2 primary Ca sources (limestone or Ca-formate) and 5 Ca/P levels. There was a positive control diet (PC; 0.76% Ca, 0.34 dP) and 4 negative control diets (NC; 0.56% Ca, 0.34% dP) supplemented with phytase at 0, 750, 1,500, and 3,000 FYT/kg. At d 10, piglets were individually housed in metabolism crates and fed 3.2 x metabolic weight. On d 14 to 18, fecal and total urine samples were collected. Apparent total tract digestibility (ATTD) was calculated for dry matter (DM), organic matter (OM), crude protein (CP), ash, Ca, and P using TiO2 as marker. Urinary P was measured to calculate P retention. These data were analyzed as a 2-way interaction. On d 0 (baseline), 8 and 18, blood samples were collected to analyze serum Ca and P, and plasma inositol. Blood data were analyzed as a 3-way interaction. Results indicated that piglets fed Ca-formate had greater ATTD of Ca (75.0% vs. 71.4%, P &lt; 0.01) but decreased ATTD of P (66.4% vs. 68.8%, P &lt; 0.01), than piglets fed limestone. Phytase supplementation improved ATTD of DM, ash, OM, CP, P, and Ca compared with the NC and PC. An interaction between Ca/P levels and Ca-sources was observed for urinary P (P = 0.03), as there were no differences between Ca sources in piglets fed the NC or the 750 FYT diets, but piglets fed the PC diet and the NC+1,500 or 3,000 FYT with limestone had greater urinary P compared with Ca-formate. A 2-way interaction between Ca/P levels and d was observed for plasma inositol (P = 0.012). On d 8 and 18, there was no difference between the NC and PC;, however, phytase supplementation at 750, 1,500, and 3,000 FYT increased plasma inositol on d 8 (58.2, 80.7, and 89.5 μmol) and d 18 (70.2, 85.4, and 106.4 μmol). There was only a main effect of Ca/P levels in serum P. Compared with the NC (73.7 mg/L), the PC and the NC+750, 1,500, and 3,000 FTU/kg increased serum P (90.3, 89.1, 87.6, and 93.2 mg/L, respectively, P &lt; 0.01). There was no effect of Ca source on blood inositol and P. No significant dietary treatment effects were observed in serum Ca. In conclusion, using Ca-formate instead of limestone increases Ca digestibility but reduces P digestibility, likely due to a greater Ca solubility of Ca-formate. This suggests that diets should be formulated based on digestible Ca instead of total Ca.