bluuebunny/crossref_metadata_2025 huggingface dataset:
253 The influence of corn-based fiber on digesta short chain fatty acid composition and pH in growing pigs
Authors: Miller Hannah , Self Rachel , Sasser Cassidy , Balser Amelia , Legako Jerrad F , Hernandez Sebastian , Broadway Rand R , Sanchez Nicole C Burdick , Carroll Jeff A , Petry Amy L
Published: May 2024

Pigs can obtain energy from fibrous feedstuffs through a symbiotic relationship with their gastrointestinal microbiome, which results in the production of metabolites, such as short chain fatty acids (SCFA). An experiment was conducted with the objective of investigating how different insoluble corn-based fiber sources influence changes in SCFA composition along the digestive tract of growing pigs. Two replicates of 28 gilts [n = 56; initial body weight (BW) = 26.7 ± 2.5 kg; PIC800 x Camborough], were randomly assigned to one of 7 semi-synthetic diets. Dietary treatments included a control (CTL) diet with a formulated total dietary fiber (TDF) value of < 1% and 6 diets with a CBF replacing 30% of the corn starch in CTL: dehulled degermed corn (DHDG; TDF = 1.09%), ground corn (COR; TDF = 3.24%), high protein dried distiller’s grains (HP; TDF = 8.79%), dried distiller’s grains (DDGS; TDF = 9.35%), corn gluten meal (CGM; TDF = 9.88%), and corn bran (BRN; TDF = 13.15%). Pigs were individually housed, and limit-fed at 2.4 times maintenance. On d 31, pigs were necropsied, and ileal, cecal, and colonic digesta were collected for immediate SCFA analysis and stomach, jejunal, ileal, and cecal digesta pH was measured. Data were analyzed as a linear mixed model with treatment as a fixed effect, replicate as a random slope or fixed effect, where appropriate, using the mixed procedure of SAS. There were no differences in jejunal nor stomach pH (P ≥ 0.51). Ileal pH was greatest (P = 0.01) in HP, DDGS, and CGM diets. Cecal pH was greatest (P < 0.01) in the BRN diet and lowest in COR and HP. Molar proportions of ileal SCFAs did not differ (P ≥ 0.74) among treatments. In the cecum, molar proportions of butyrate production did not differ (P = 0.74). Cecal acetate proportions were less (P = 0.03) in CTL, COR, and HP compared with all other treatments (51.54, 61.09, 51.92, 52.89, 59.16, 63.87, and 63.32%, for CTL, DHDG, COR, HP, DDGS, CGM, and BRN, respectively). Cecal propionate proportions were greatest (P = 0.01) in BRN and least in DHDG, COR, and CGM (30.85, 27.67, 27.67, 30.91, 30.47, 24.03, and 35.86% for CTL, DHDG, COR, HP, DDGS, CGM, and BRN, respectively). Relative to CTL, isobutyrate proportions in the cecum for COR, HP, and DDGS were reduced by 65%, 52%, and 53%, respectively (P < 0.01). In the colon, there were no differences in molar proportions of acetate, butyrate, nor isobutyrate (P ≥ 0.254). However, HP and CGM had a smaller (P = 0.04) proportion of propionate in the colon and COR and BRN had the greatest proportion of colonic propionate (33.92, 29.68, 38.41, 25.3, 30.00, 26.76, and 37.94% for CTL, DHDG, COR, HP, DDGS, CGM, and BRN, respectively). Collectively, the different fibrous components of CBFs can influence SCFA proportions in the growing pig.
250 Effects of premix carriers rich in iron, calcium, or fiber on growth performance of early-growing pigs
Authors: Cheng Liangkai , Liu Xule , Srisap Thirayot , Ju Tingting , Stoner Gary , Wantanasak Apichat , Guo Jiyao , Xu Xiao
Published: May 2024

The study was to evaluate the effect of premix carriers rich in iron (sand), calcium (limestone), or fiber (rice hull) on growth performance of early-growing pigs. A total of 215 pigs [initial body weight (BW) = 39.90 ± 5.06 kg) were randomly allotted to 3 dietary treatments containing 2% of different premix carriers: sand, limestone, or rice hull (30% crude fiber) using initial BW and sex as blocks (5 to 6 pigs per pen, 14 pens per treatment). The total Ca in sand, limestone, and rice hull were 4.28, 39.52, and 0.27 %, respectively, with Fe levels of 2.39, 0.20, and 0.05%, respectively. The analyzed total Ca level of the experimental diet containing sand, limestone, or rice hull was 0.69, 0.71, or 1.88 %, the analyzed total P level was 0.49, 0.49, or 0.48 %, and the analyzed total Fe level was 305, 633, or 347 ppm, respectively with 144 ppm of Fe from FeSO4·H2O in each diet. During the 28 d of the experiment, BW, feed disappearance, and fecal scores (ranging from 0 to 3 with 3 indicating watery feces) were recorded. Blood and feces were collected at the end of the experiment to measure the ATTD of dry matter (DM) and CP, serum iron concentration, hemoglobin, and red blood cell count. Data were analyzed by ANOVA using the Mixed Procedure of SAS with different premix carriers as the fixed effect. Limestone reduced the average daily gain (ADG; P < 0.05, 0.871 vs. 0.965 and 0.935 kg/d), increased feed conversion ratio (FCR; P < 0.05, 2.55 vs. 2.33 and 2.36), and aggravated diarrhea severity as reflected by greater fecal scores (P < 0.05, 1.53 vs. 1.18 and 1.19) compared with sand and rice hull as carriers. The ATTD of both DM and CP in pigs fed a premix with sand as a carrier were greater than that in rice hull- or limestone-treated pigs (P < 0.05, DM: 86.7 vs. 77.7 or 74.1%; CP: 86.1 vs. 75.0 or 73.3%). Furthermore, pigs fed a premix containing sand exhibited the greatest serum iron concentrations among treatment groups (sand, limestone, and rice hull: 2.81, 1.93, and 1.69 mg/L). However, no significant difference was observed in red blood cell count or hemoglobin concentrations among groups. In sum, excessive limestone in premix can negatively affect growth performance and fecal consistency, whereas using sand rich in iron as a carrier in premix exerted minimal impact on nutrient digestibility as opposed to limestone or rice hull.
247 Evaluating the use of soybean hulls on growth performance, carcass composition, and digestibility when fed to grow-finish pigs
Authors: Miller Kayla A , Mendoza Omarh F , Sparks Chris , Gabler Nicholas K
Published: May 2024

The addition of fiber to grow-finish diets is commonly utilized in swine production formulation as energy costs increase. The objective of this study was to determine the effects of feeding soybean hulls (SBH) at increasing levels to grow-finish pigs on growth performance, carcass characteristics, and apparent total tract digestibility (ATTD) of nutrients. Utilizing 192 grower pigs [PIC 337×1050, initial body weight (BW) = 21.99 ± 2.75 kg] that were randomly assigned to split sexed pens (n = 12 pens/treatment), pens were assigned to one of four dietary treatments and fed over three feeding phases for the estimated BW ranges of 22 to 50 kg, 50 to 86 kg, and 86 to 127 kg. Diets were formulated to represent conventional corn and soybean meal diets, containing increasing levels of SBH at: 1) 0% SBH (0%); 2) 7.5% SBH (7.5%); 3) 15% SBH (15%); and 4) 22.5% SBH (22.5%). Within phase, diets had equal SID Lys:ME and energy was allowed to float. Individual BW and pen feed disappearance were collected for each phase to calculate pen average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency gain to feed ratio (G:F). On d 56 of study and during phase 2, 32 gilts (n = 8) were placed into individual metabolism crates, where total urine and feces were collected for 72 h to measure ATTD of gross energy (GE), nitrogen (N), neutral detergent fiber (NDF), and acid detergent fiber (ADF), then returned to original pens. At the completion of study, carcass weight, backfat depth, and loin depth were collected. Data were analyzed with the fixed effects of dietary treatment by ANOVA, linear, and quadratic contrasts. Pen served as the experimental unit for performance and carcass characteristics and pig as the experimental unit for ATTD analyses. Overall, as SBH increased from 0% to 22.5%, ADG tended to decrease (linear P = 0.060) with no difference in ADFI (P > 0.05), resulting in an overall decrease in G:F (0.38, 0.37, 0.36, 0.35; linear P < 0.001; 0, 7.5, 15 and 22.5% SBH, respectively). Final BW tended to decrease (linear P = 0.069) and carcass weight decreased (102.9, 102.7, 99.7, and 96.5 kg, linear P < 0.001) as SBH increased in diet. Carcass fat depth (P = 0.014) and loin depth (P = 0.006) linearly decreased with increasing levels of SBH in the diet. Increasing levels of SBH from 0% to 22.5% decreased ATTD of GE and N (linear P < 0.001) and tended to increase ATTD NDF and ADF (linear P = 0.056 and P = 0.073, respectively). Altogether, these data suggest increasing dietary SBH in grow-finish pig diets decreases growth efficiency and the digestibility of GE and N. Further, feeding high inclusion rates of SBH negatively impacts carcass yield, backfat and loin depth.
246 The effect of trypsin inhibitor unit concentrations from raw soybeans in grower pig performance and protein digestibility
Authors: Miller Kayla A , Nisley Mitchell J , Mendoza Omarh F , Spencer Joel D , Krishnan Hari B , Gabler Nicholas K
Published: May 2024

Soybeans contain two major protease inhibitors, Kunitz trypsin and Bowman-Birk protease inhibitors, both of which are anti-nutritional components that can be directly linked to a reduction in amino acid bioavailability and growth performance in swine. Therefore, the objective of this study was to determine the level at which trypsin inhibitor units (TIU, expressed as TIU/mg of complete feed), coming from raw soybeans, in pig diets result in reduction in growth performance and digestibility. This study used 45 grower gilts initial body weight (BW) = 39.7 ± 2.1 kg] that were individually penned and fed one of five dietary TIU treatments (n = 9 pigs/trt) in a complete randomized design. Diets were representative of a commercial corn-soybean meal diet and formulated to have ranging TIU/mg of complete feed of 0.89, 1.77, 3.55, 6.99, and 11.54 TIU/mg utilizing raw ground soybeans and soybean meal at incremental levels. Analyzed diets contained 0.99, 2.23, 3.07, 6.49, and 9.38 active TIU/mg. Diets were balanced to the same grams of SID Lys:ME of 2.85 and NDF concentration of 7.4% utilizing soybean oil and soybean hulls, respectively. Individual feed intake was recorded throughout, and pig BW were collected on d 0, 21, and 27 to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency gain to feed ratio (G:F). All pigs were placed into metabolism crates on d 21 for 6 d to determine apparent total tract digestibility (ATTD) of nitrogen (N), N excretion and N balance. Growth performance and ATTD data were analyzed with pig as the experimental unit and diet TIU level as a fixed effect using ANOVA, linear, and quadratic contrast models. Overall, ADG decreased as diet TIU increased (1.07, 1.03, 1.02, 0.91, and 0.83 kg/d, respectively, linear P < 0.001). However, no differences in ADFI (P > 0.10) were reported and this resulted in a decrease in G:F (0.48, 0.45, 0.43, 0.41, 0.36, respectively, linear P < 0.001) as dietary TIU concentrations increased from 0.99 to 9.38 TIU/mg. Compared with 0.99 TIU/mg, pigs fed 9.38 TIU/mg had a 9.32% reduction in final BW (68.7 vs. 62.3 kg, linear P < 0.001). Apparent total tract digestibility of N decreased when pigs were fed 9.38 TIU/mg compared with 0.99 and 2.23 TIU/mg (83.26% vs. 90.29% and 89.57%, respectively, P < 0.001). In conclusion, as total trypsin inhibitor units increase in complete feed of grower pigs, digestibility of protein, growth rates and feed efficiency are reduced in a linear manner.
251 Effects of feeding increasing levels of dimethylglycine (DMG) on growth performance, livability, and carcass characteristics of commercial finishing pigs
Authors: Song Ran , Shelton Nick , Schuling Sarah E , Knudtson Sue M , Miller Jodi , Schimek Dan E , Friesen Kim
Published: May 2024

This study aimed to evaluate the impact of increasing dietary levels of 78% sodium dimethylglycine (DMG) on growth performance, livability, and carcass characteristics of commercial finishing pigs. A total of 1,115 mixed-sex finishing pigs [initial body weight (BW) = 70.1 ± 1.8 kg] were housed in pens with 25 to 27 pigs per pen. Pens within block were assigned randomly to one of four dietary treatments containing 0 (Control), 0.25 (DMG_0.25), 0.5 (DMG_0.5) or 1.0 (DMG_1.0) g DMG/kg of feed with 11 replicates per treatment. This experiment extended over an 8-wk period until pigs were harvested at 125.4 ± 0.8 kg of BW. Data were analyzed using the MIXED procedure of SAS, and preplanned orthogonal contrasts were conducted to evaluate pairwise comparisons as well as linear and quadratic effects related to the increased levels of DMG. While no linear effect was observed, there was a tendency for a quadratic response in closeout feed efficiency (G/F; P = 0.08) and the percentage of pigs with morbidity (P = 0.06), with the most favorable responses found in pigs fed DMG_0.25 (Table 1). Pairwise comparisons between Control and DMG_0.25 treatments suggest that pigs receiving DMG_0.25 showed a 6% increase in closeout average daily gain (ADG; 1.01 vs. 0.95 kg/d; P = 0.02) and a 4% increase in closeout G/F (0.337 vs. 0.324; P = 0.05) compared with those fed Control diet. Furthermore, DMG supplemented at 0.25 g/kg tended to be associated with decreased mortality (P = 0.08), reduced morbidity (P = 0.09) and more pigs sold to the primary market (P = 0.10) compared with Control. In contrast, dietary supplementation of greater concentrations of DMG at 0.5 and 1.0 g/kg were not different compared with Control (P > 0.10). Carcass characteristics, including hot carcass weight, carcass yield, fat depth, loin depth, and fat-free carcass lean, were not different among treatments. The findings of this study suggest dietary supplementation of DMG at 0.25 g/kg of feed enhanced growth performance and livability in finishing pigs. However, feeding greater concentrations of DMG, up to 1.0 g/kg of feed, did not produce different outcomes compared with Control. These results indicate the potential benefits of DMG at specific inclusion rate in optimizing the production and health of finishing pigs.
252 Evaluation of phase feeding and complete diet blending at different standardized ileal digestible lysine levels on finishing pig growth performance, carcass characteristics and diet costs
Authors: Navales Ron Aldwin S , Tokach Mike D , Krogstad Dwayne , DeRouchey Joel M , Gebhardt Jordan T , Goodband Robert D , Woodworth Jason C
Published: May 2024

A total of 2,160 mixed-gender pigs [PIC 337 × 1050; initial body weight (BW) = 24.9 ± 0.97 kg) were used in the 120-d study to compare feeding strategies (phase feeding vs complete diet blending) at different SID Lys levels (90 vs 100% of suggested requirement estimates) on finishing pig growth performance, carcass characteristics, and economics. Pens of 27 pigs were assigned to 1 of 4 treatments in a completely randomized block design with barn and initial BW as blocking factors resulting in 20 pens/treatment. The treatments included two feeding programs: a 5-phase feeding strategy at either 90% (Phase-90) or 100% of SID Lys requirement estimates (Phase-100) or blending of complete diets with pre-defined mixing proportions of a low and high SID Lys diet to meet 90 (Blend-90) or 100% (Blend-100) of the SID Lys curve requirement estimates for 23 to 127 kg pigs. Lysine levels were based on PIC 2021 requirement estimates. The 90% SID Lys diets were formulated to contain 4.38, 3.73, 3.06, 2.66 and 2.44 g SID Lys per Mcal NE for phases 1 to 5, respectively. The 100% SID Lys diets were formulated to contain 4.86, 4.15, 3.40, 2.96 and 2.71 g SID Lys per Mcal NE for phases 1 to 5, respectively. Pigs in phase-feeding strategies were fed on a feed budget with 21, 65, 67, 63 and 62 kg per pig for phases 1 to 5, respectively. Final BW and overall average daily gain (ADG; d 0 to 120) were not affected by the feeding strategy nor by diet SID Lys levels. In contrast, overall average daily feed intake (ADFI0 of pigs fed by diet blending was less than those fed by phase feeding (P = 0.002) resulting in increased gain to feed ratio (G:F; P < 0.001) for pigs fed by diet blending (table). The SID Lys levels did not influence overall ADFI or G:F. Hot carcass weight, carcass yield, percentage lean, fat depth and loin depth were not affected by the feeding program. Despite the decreased overall ADFI and increased G:F of pigs fed by diet blending, feeding strategy resulted in no significant differences in economic criteria except for reduced feed cost per kg gain at high price scenario (P = 0.049) for diet blending. With low diet cost, the 90% SID Lys level resulted in decreased feed cost per pig and feed cost per kg gain than 100% SID Lys (P < 0.001), but differences were not detected in income over feed cost (IOFC). In conclusion, diet blending at either 90 or 100% of the SID Lys requirement estimate reduced ADFI and increased G:F without impacting average daily gain (ADG) or carcass characteristics. At ingredient prices used in this study, feeding strategies at either 90 or 100% SID Lys did not significantly affect IOFC, but feeding 90% of SID Lys recommendation reduced feed cost.
248 Effects of feeding finishing pig diets differing in Ca:P ratio, added phytase and 25(OH)D3 on growth performance, serum 25(OH)D3, carcass characteristics, and bone characteristics
Authors: Cordoba Hilario M , Woodworth Jason C , Goodband Robert D , DeRouchey Joel M , Tokach Mike D , Gebhardt Jordan T , Bergstrom Jon R
Published: May 2024

A total of 2,160 pigs [337 × 1050, PIC; initial body weight (BW) = 33.2 ± 1.4 kg] were used in a 114-d trial to determine the effects of feeding diets differing in Ca:P ratio and added phytase or phytase and 25(OH)D3 (Hy-D, DM Nutritional Products, Parsippany, NJ) on growth performance, carcass characteristics, serum 25(OH)D3, and bone characteristics. Pigs were housed in mixed sex pens with 27 pigs per pen and 20 pens per treatment. The four treatments were assigned to pens in a randomized complete block design and consisted of 1) a high phosphorus (HP) diet with standardized total tract digestibility (STTD) P at 115% of NRC (2012) requirement estimate without added phytase and formulated to a 1.25:1 Ca to P ratio; 2) low phosphorus (LP) diet with STTD P at 80% of NRC requirement without added phytase and formulated to a 1.25:1 Ca to P ratio; 3) HP with phytase (HP+phytase) diet with STTD P at 115% of NRC requirement using 0.125% STTD P release from 600 FYT/kg HiPhorius and 1.1:1 Ca to P ratio; and 4) Diet 3 except 25(OH)D3 replaced most of the vitamin D3 in the diet (HP+25(OH)D3). Diets were fed in 4 phases from 32 to 50, 50 to 75, 75 to 100, and 100 to 133 kg. For overall growth performance, source of vitamin D had no impact on performance. Pigs fed HP diets had improved (P < 0.05) average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F) compared with those fed LP diets, and increased ADFI compared with those fed the HP+phytase diets (Table 1). For 25(OH)D3 measured on d 50, pigs fed the HP diets had increased (P < 0.05) serum 25(OH)D3 compared with pigs fed the LP diets and pigs fed the HP+25(OH)D3 diets had increased (P < 0.05) serum 25(OH)D3 compared with pigs fed the HP+phytase diets. Pigs fed the HP diets had greater (P < 0.05) HCW and percentage lean than those fed LP diets. For bone analysis, pigs fed HP diets had greater (P < 0.05) bone ash (g) and breaking strength than pigs fed LP or HP+phytase and 1.1:1 Ca to P ratio. In conclusion, compared with pigs fed LP diets, HP-fed pigs had improved performance and HCW. Dietary 25(OH)D3 replacing D3 did not impact performance but increased circulating 25(OH)D3.
262 Modulation of vitamin D, calcium and phosphorous metabolism and immune response in pre- and post-weaning piglets under different vitamin D supplementation strategies
Authors: Dalto Danyel Bueno , Villeneuve Geneviève , Guay Frédéric , Matte J Jacques , Lapointe Jérôme
Published: May 2024

This study evaluated the impact of different vitamin D supplementation strategies to pre- and post-weaning piglets on vitamin D, calcium and phosphorous metabolism and immune status. Sixty piglets were selected at d 2 of age [body weight (BW) = 1.71 ± 0.03 kg] and orally supplemented with saline (CTR) or a solution of 25(OH)D3 at d 2, d 8, and d 21 (0.1, 0.2 and 0.3 mg, respectively) along with UVB exposure every second day from d1 4 up to d 21 (HD). From weaning (d 21) until d 42, CTR animals were supplemented with 2,000 UI of vitamin D3/kg of feed and HD animals were supplemented with 2,000 UI 25(OH)D3/kg. Piglets were sacrificed at d 21, d 28, and d 35 (n = 10/treatment/d) for the collection of blood, jejunum, liver, and kidney samples. Serum 25(OH)D3 concentrations were determined by HPLC and the mRNA expression of genes implicated in vitamin D, calcium and phosphorous metabolism and immune status were assessed by quantitative real-time PCR. Data were analyzed using a 2x3 factorial design. Serum 25(OH)D3 concentrations were 2.8, 3.6, and 2.2-fold greater in HD piglets at d 21, 28, and 35 (P ≤ 0.01), respectively (Table 1). No treatment or treatment x time interaction was detected on the expression of genes related to vitamin D metabolism in the jejunum mucosa and liver (P ≥ 0.19). In kidney, HD piglets had greater expression of CYP27B1 (P = 0.09) and decreased expression of CYP24A1 (P = 0.06). Renal EGR1 expression was greater in HD piglets (P = 0.01). No treatment effect was detected on the expression of genes directly implicated in phosphate or calcium reabsorption (P ≥ 0.16). No treatment or treatment x time interaction was detected on the mRNA expression of selected genes related to immune response in the jejunum mucosa, liver, and kidney (P ≥ 0.14). Independently of vitamin D treatments, time effects were detected for gene expression. The mRNA expression of CYP27B1 increased and that of CYP24A1 decreased from d 28 to 35 (P ≤ 0.04) in kidney. Genes related to calcium (TRPV5) and phosphate (NPT2c) reabsorption in kidney had reduced mRNA expression on d 35 compared with d 21 (P ≤ 0.01). Overall, the mRNA expression of genes related to immune response in all studied tissues was lower at d 35 compared with d 21 (P ≤ 0.08). Bodyweight at slaughter was not affected by treatments at d 21, 28, and 35 (P ≥ 0.29). In conclusion, pre-weaning vitamin D supplementation enhanced vitamin D status at weaning and the use of dietary 25(OH)D3 supplementation was more effective in increasing the vitamin D status post-weaning. The mRNA expression results suggest that greater vitamin D status at weaning and during the first 2 wk post-weaning do not affect calcium and phosphate reabsorption in kidney and the immune defense of pre- and post-weaning piglets.
256 Anchor Talk: Accounting for effects of microbial phytase on digestibility of calcium and phosphorus
Authors: Stein Hans H
Published: May 2024

Inclusion of increasing levels of microbial phytase in diets for weanling and growing pigs results in a linear increase in the standardized total tract digestibility (STTD) of Ca and P. In many experiments, maximum effects on STTD of Ca and P were obtained with inclusion of around 1,200 phytase units (FTU) per kg of diet, although some of the newer phytases appear to release Ca and P until at least 2,000 FTU is included in the diets. In most individual feed ingredients and most practical diets, the maximum standardized total tract digestibility (STTD) of P that is obtained by using between 500 and 1,000 FTU per kg diet is around 70%, whereas the STTD of Ca for some ingredients can be over 80% if microbial phytase is used. One reason for the decreased STTD of P than of Ca in diets with maximum dosages of phytase is that dietary Ca prevents some P from being absorbed, and the STTD of P in practical diets, therefore, will never be 100% regardless of phytase inclusion. It is, however, important that the increased STTD of dietary Ca that is caused by phytase is taken into account in diet formulation because of the negative effects of Ca on STTD of P. In addition, at low dietary phytase there is release of more Ca than P, whereas at greater inclusion levels of phytase, there may be a similar release of Ca and P. Release of Ca and P by phytase is also impacted by ingredient composition in the diets because phytase does not have the same effect on all ingredients. In general, ingredients with low concentration of phytate have greater STTD of P if no phytase is used than ingredients with greater concentrations of phytate P, but the response to phytase is greater for ingredients with high concentrations of phytate. Sows also have lower digestibility of Ca and P than growing pigs and the response to phytase in diets for sows is less than in diets for growing pigs. Likewise, there is a linear reduction in phytase effects on STTD of both Ca and P as pigs get older. In contrast, in diets for newly weaned pigs there are specific advantages to using high concentrations of phytase (at least 2,000 FTU) because gastric pH is reduced in diets with phytase, which results in less diarrhea. This effect may be related to increased concentrations of plasma inositol in pigs fed diets with phytase, which may positively impact the immune status of the pigs. In conclusion, use of phytase in diets for pigs results in increased STTD of Ca and P and may have other benefits as well.
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

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 > 0.10). However, body BMD decreased (0.843, 0.841, 0.804, 0.706, and 0.585 g/cm2) as tCa:avP increased (P < 0.001). In T2, as tCa:avP increased, ADG decreased (0.85, 0.85, 0.77, 0.73, and 0.67 kg/d; P < 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 < 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

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 < 0.001). Consequently, ADG and ADFI were significantly reduced as avP decreased (P < 0.001). Compared with the adequate avP pigs, whole body BMD was reduced by 22% and 65% in marginal and deficient avP pigs (P < 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 < 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 < 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 < 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

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

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 > 0.05) for differences in growth performance. There was no evidence (P > 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

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 < 0.001). Pigs fed diets containing 1,000 units of phytase had greater (P < 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 < 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

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 > 1.5 were consistent with deficient P intake, ratios from 0.5 to 1.5 reflected P adequacy, and ratios < 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

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 < 0.05. Liveability % was not different between treatments. The reduction of Ca and digestible P in NC did not affect growth performance (P > 0.05) but reduced bone ash % compared with PC (P < 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 < 0.05), feed efficiency (1.60 vs 1.50 for NC and NC + 3000 phy, respectively; P < 0.05) and bone mineralization (P < 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

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 < 0.01) but decreased ATTD of P (66.4% vs. 68.8%, P < 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 < 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.