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The objective was to test the hypothesis that an increasing dose of a novel thermostable 6-phytase that was derived from E. coli and expressed in a Pichia Pastoris yeast (Superphy; Hanley International, LLC, Belmont, MA) increases apparent total tract digestibility (ATTD) of minerals and energy by pigs. Forty-eight barrows (initial weight: 22.61 kg) were housed in metabolism crates and fed 6 diets based on corn and soybean meal. The positive control (PC) diet contained P at the requirement. The negative control (NC) diet contained no feed phosphate, but contained 0, 250, 500, 1,000, or 2,000 phytase unit/kg. Feces were collected for 4 d after 5 d of adaptation. Dried and ground fecal samples were analyzed for dry matter, energy, Ca, P and other minerals. Data were analyzed using a model that included diet as fixed variable and contrast statements were used to compare PC and NC diets and to demonstrate linear and quadratic effects of phytase. Results indicated that ATTD of dry matter and energy and concentration of digestible energy in NC without phytase were greater (P < 0.05) than in PC, but ATTD of ash, K, Mg, Na, Cu, Fe, Mn, and Zn was not different between the 2 diets. There was no effect of phytase on ATTD of dry matter and energy or on digestible energy in diets. As dietary phytase increased, ATTD of ash and Mg increased (linear, P < 0.05) and ATTD of Ca and the standardized total tract digestibility (STTD) of P also increased (quadratic, P < 0.05), but ATTD of K, Na, Cu, Fe, Mn, and Zn was not affected by phytase. In conclusion, the novel enhanced E. Coli based phytase increased ATTD of Ca, P, and Mg and STTD of P if included in a diet containing Ca and P below requirements.

An experiment was conducted to test the hypothesis that increasing levels of phytase increases apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients in diets fed to young pigs. A negative control (NC) diet that was deficient (compared with NRC recommendation) in total Ca (-0.15%), standardized total tract digestible P (-0.16%), net energy (-33 kcal/kg), and standardized ileal digestible amino acids (average -0.02% unit) was formulated. Five additional diets were formulated by adding 250, 500, 1,000, 2,000 or 4,000 phytase units per kg of a novel consensus bacterial 6-phytase variant (PhyG) to the NC diet. All diets were based on corn, soybean meal, and canola meal. Eighteen ileal-cannulated pigs (17.81 ± 1.71 kg) were allotted to a 6 × 3 incomplete Latin square design with 6 diets and 3 periods. There were 3 pigs per diet in each period; therefore, there were nine replicate pigs per diet. Data were analyzed using the Mixed Procedure of SAS with diet as the fixed effect whereas pig and period were considered random effects. Linear and quadratic effects of PhyG on nutrient digestibility were determined using polynomial contrast statements. Linear (P < 0.01) and quadratic (P < 0.05) increases in AID of all individual amino acids (except Arg) were observed as dietary concentrations of PhyG increased (Table 1). Likewise, an increase (linear, P < 0.01; quadratic, P < 0.05) in ATTD of minerals in diets was observed as the concentration of PhyG increased in diets. Increasing levels of PhyG in diets also increased (linear, P < 0.05) ATTD of gross energy. In conclusion, increasing levels of the novel phytase (PhyG) effectively increased ileal and total tract digestibility of nutrients by pigs.

An experiment was conducted to test the hypothesis that probiotic Bacillus toyonensis M15750 improve the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of energy and nutrients when included in diets fed by weanling pigs. A control diet was formulated based on corn, soybean-meal, and distillers dried grains with solubles and a second diet was formulated by supplementing the probiotic Bacillus toyonensis M15750 (1 × 109 cfu/kg feed) to the control diet. Titanium dioxide (0.50 %) was added to the diets as an indigestible marker. Sixteen weanling barrows (10.7 ± 0.7 kg) that had a T-cannula in the distal ileum were allotted to the two diets with 8 replicate pigs per diet in a randomized complete block design with body weight being the blocking factor. Pigs were adapted to the diets and to the metabolism crates for 7 days, urine and fecal materials were collected during the following 4 days according to standard procedures using the marker-to-marker approach, whereas ileal digesta were collected for 8 h during the following 2 days. The AID and ATTD of energy and nutrients were calculated for each diet. The AID of dry matter and gross energy was greater (P < 0.05) and the AID of starch tended to be greater (P = 0.05) in the diet supplemented with the probiotic Bacillus toyonensis M15750 compared with the control diet (Table 1). However, no differences were observed for the ATTD of energy or nutrients between the 2 diets, which indicates that the increased digestibility in the small intestine of pigs fed the diet supplemented with Bacillus toyonensis M15750 was offset by a reduction in hindgut fermentation. These results indicate that inclusion of probiotic Bacillus toyonensis M15750 in diets for weanling pigs have the potential to improve the AID of dry matter, gross energy and starch.

Background: It is not feasible to determine the true ileal amino acid (AA) digestibility of protein sources in humans on a routine basis, and the growing pig has been recommended as an animal model for this purpose but requires further validation.Objectives: To determine and compare true ileal AA digestibility between adult human ileostomates and growing cannulated pigs for a range of food proteins.Methods: Seven protein sources (black beans, bread, collagen, pigeon peas, wheat bran, whey protein isolate, and zein) that spanned the range of digestibilities typically seen in foods were evaluated. Six female growing pigs received each of the protein sources, as well as a protein-free diet, and digesta were collected via ileal T-cannula. Adult human ileostomates consumed the same protein sources (5–8 ileostomates, depending on the protein source), as well as a protein-free diet, and digesta were collected. Titanium dioxide and celite were included in the diets as indigestible markers. True ileal AA digestibility coefficients were determined.Results: There was a significant effect of protein source (P ≤ 0.001) for all AAs. The effect of species was not significant (P > 0.05) except for total lysine (but not for available lysine). When analyzed within diets, the statistically significant species effect for true lysine digestibility was found for black beans only. Pig and human digestibility values were generally highly and significantly (P ≤ 0.05) correlated. A linear regression equation derived for true ileal AA digestibility (given as coefficients) determined in the human and pig for the overall mean of all AAs was (y = human, x = pig) y = 1.00x – 0.010, with the slope not statistically significant (P > 0.05) from unity and the intercept not different (P > 0.05) from zero.Conclusions: True ileal AA digestibility values determined in the growing pig can be directly used for predicting digestibility in adult humans.

An experiment was conducted to test two hypotheses: 1) reducing dietary Ca and P reduces gastric pH and diarrhea in weanling pigs; 2) negative effects of low Ca and P on pig growth performance may be overcome if phytase is added to the diets. A total of 320 weanling pigs (6.35 ± 0.87 kg) were allotted to eight corn-soybean meal-based diets in a randomized complete block design with five pigs per pen. Two phase 1 (days 1 to 14) control diets containing 100 or 50% of total Ca and digestible P relative to the requirement, and six diets in which 500, 2,000, or 16,000 units of phytase/kg feed (FTU) were added to each control diet were formulated. Phytase was assumed to release 0.16% total Ca and 0.11% digestible P. Common diets were fed in phases 2 (days 15 to 27) and 3 (days 28 to 42). Growth performance data were recorded within each phase. Data for fecal scores and gastrointestinal pH were recorded for phase 1. Colon content (day 14), the right femur (days 14 and 42), and blood samples (days −1, 14, 27, and 42) were collected from one pig per pen. In phase 1, reducing Ca and P did not reduce gastric pH or fecal score, but pigs fed the 50% diets had reduced (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI) compared with pigs fed the 100% diets. In both 50% and 100% diets, phytase above 500 FTU increased (P < 0.05) gain:feed ratio (G:F) and tended (P < 0.10) to reduce gastric pH of pigs. From days 1 to 42, pigs fed the 50% diets tended (P < 0.10) to have reduced ADG and ADFI compared with pigs fed the 100% diets, but among the 100% diets, pigs tended (P < 0.10) to have a linear increase in G:F as phytase level increased. Pigs fed the 50% diets had reduced (P < 0.05) concentrations of inositol phosphate esters (IP) in the colon and reduced bone ash (days 14 and 42) compared with pigs fed the 100% diets. Phytase did not affect bone ash or most blood metabolites. Concentrations of IP in the colon decreased, whereas plasma inositol increased (d 14; P < 0.05) in pigs fed diets with phytase (≥ 500 FTU). In pigs fed the 100% diets, IP in the colon linearly decreased (P < 0.05), but plasma inositol linearly increased (P < 0.05) with increasing levels of phytase. In conclusion, reducing Ca and P in diets for weanling pigs did not influence gastric pH or fecal score, but compromised growth performance and bone ash. However, regardless of dietary Ca and P, high doses of phytase increased phytate degradation and inositol absorption, which consequently increased G:F of pigs.

This study aimed at testing the hypothesis that greater inclusion of spray dried plasma (SDP) in diets improves growth performance, intestinal morphology, and reduces inflammation in weaned pigs. Four-hundred weaned pigs (body weight: 6.05 ± 0.80 kg) were allotted to a randomized complete block design with 5 diets and 2 blocks (16 pens/diet; 5 pigs/pen). Pens were not cleaned between groups to create a sanitation challenge. Phase-1 diets containing 0, 2, 4, 6, or 8% SDP were formulated. One pig per pen was sacrificed on d 14 and samples of intestinal tissue and mucosa were collected. Data were analyzed using PROC MIXED of SAS and linear, quadratic, and cubic contrast statements were used. During phase-1, ADG, ADFI, G:F, and body weight of pigs on d 14 increased (linear, P < 0.05) with increasing levels of SDP in the diet (Table 1). Villus width in the jejunum of pigs on d 14 tended to increase (linear, P < 0.10) with increasing inclusion of SDP (Table 2), and villus height:crypt depth tended to increase (quadratic, P < 0.10) with the greatest value observed for pigs fed a diet with 8% SDP. Secretory immunoglobulin A in the jejunal mucosa was decreased when 4 or 8% SDP was included in the diet (cubic, P < 0.05). Interleukin- (IL-) 2 (quadratic, P < 0.10) and IL-18 (cubic, P < 0.10) in the jejunal mucosa tended to decrease at 8% inclusion of SDP and IL-8 (linear, P < 0.10) tended to increase as SDP inclusion increased in the diet. In conclusion, the optimal inclusion of SDP in diets for weanling pigs was 8% as indicated by improvements in growth performance, but the collective intestinal morphology and health data do not result in a clearly conclusive optimum concentration in SDP.

The objective was to test the hypothesis that dietary P concentration and level of phytase influences basal endogenous loss of Ca in pigs. Seventy barrows (body weight: 17.66 kg) were housed in metabolism crates and allotted to 7 Ca-free diets containing corn, potato protein concentrate, and full-fat rice bran (0.27% phytate P). A positive control (PC) diet contained P at the requirement for digestible P for 11 to 25 kg pigs. Negative control (NC) diets were formulated by reducing concentration of digestible P by 0.15% and adding a novel consensus bacterial 6-phytase variant at 0, 250, 500, 1,000, 2,000, or 4,000 phytase units/kg diet. Feces and urine samples were collected separately for 4 d after 5 d of adaptation. Dried and ground fecal samples were analyzed for dry matter, Ca, and P and urine was analyzed for P. Data were analyzed using a model that included diet as fixed effect. Positive control and NC were compared using a contrast statement and linear and exponential effects of dietary phytase were tested. Results indicated that apparent total tract digestibility of dry matter was not affected by dietary P or phytase (Table 1). The basal endogenous loss of Ca was not affected by dietary P, but exponentially (P = 0.030) decreased as dietary phytase increased. Phosphorus retention (g/d) was greater (P < 0.001) in pigs fed PC compared with NC without phytase. The standardized total tract digestibility (STTD) of P exponentially (P < 0.001) increased as phytase increased; however, retention of P as % of absorbed P decreased (linear, P = 0.006) as phytase increased because the extra P absorbed as a result of phytase could not be retained due to the lack of Ca. In conclusion, increasing the phytase dose decreased basal endogenous loss of Ca and increased STTD of P.

Digestibilities of nutrients, especially protein, are crucial characteristics of milk replacers in a calf-rearing program. Endogenous synthesis of proteins and microbial fermentation in the large intestine alter apparent total-tract digestibility of AA. Therefore, collection of digesta samples at the end of the ileum is the only method to estimate true small intestinal digestibility of AA. The aim of this work was to evaluate the effectiveness of inserting a T-cannula into the distal ileum of preweaning calves for use in digestibility studies. A second objective was to evaluate the use of a "broken-line" statistical model to compare treatment effects on calf growth and digesta pH. A T-cannula was surgically installed in the terminal ileum of 2 calves approximately 5 cm anterior to the ileocecal junction at 15 d of age, and 2 paired noncannulated calves were used as controls. Cannulation did not affect mean body weight (BW), average daily gain, milk and water intakes, and body frame dimensions. However, final BW (89.2 vs. 94.6 kg) was lower and starter intake (0.06 vs. 0.21 kg/d) tended to be decreased in cannulated calves compared with control calves. No effects on health scores, rectal temperature, or the odds of incurring diarrhea or being medicated were observed. Flow of digesta (46.4 ± 0.04 g/h) increased linearly after feeding, whereas there was a quadratic effect of time on digesta pH, with the nadir at approximately 8.5 h postfeeding. The broken-line model successfully fitted daily fluctuations of pH and allowed us to detect differences in growth slopes between cannulated and control calves. Despite the expected negative effect on BW, we conclude that this technique permitted sampling of representative ileal digesta while allowing satisfactory growth and health of the calves.

Due to the variations in nutrient quality of soybean meal (SBM) that is a result of differences in production location and processing specifications, a study was conducted to determine the fluctuations in apparent digestibility coefficients of differently sourced SBM fed to Pacific white shrimps (Litopenaeus vannamei). Twenty‐four SBM‐based diets were formulated by mixing a basal diet and test ingredients on a dry matter basis (70:30 ratio), while 1% chromic oxide was used as the inert marker. The digestibility trial was carried out in a semi‐closed recirculation system with six replicate groups per treatment (mean shrimp weight of 10.2 g). Significant differences were observed for apparent dry matter, energy and protein digestibility coefficients (p

Protein undernutrition is a serious global problem that results in stunted growth, disease, and premature death in millions of people annually. Protein deficiency is caused by a deficiency in specific indispensable amino acids and efforts to alleviate protein malnutrition, therefore, need to focus on the provision of adequate quantities of digestible indispensable amino acids. The digestibility of amino acids is most correctly determined at the end of the small intestine, and digestibility values obtained using this approach are termed “ileal digestibility values.” The total protein provision to an individual is based on the sum of digestible indispensable amino acids consumed in a meal. The protein quality of a single ingredient is less important than the quality of the mixed meal that is consumed. To assist in calculating the protein quality of meals for humans, the FAO recommends that a system called the “Digestible Indispensable Amino Acid Score” or DIAAS be used. This system is based on the ileal digestibility of each amino acid in individual protein foods, but allows for the calculation of the quality of a meal consisting of a number of protein foods. The system can then be used to assess the quality of total protein intake consumed as a meal. Comparison of this value to the requirements for indispensable amino acids by humans can be used to estimate an individual’s protein status.

An experiment was conducted to test the hypothesis that Val from a spray dried L-Val fermentation biomass (Val-FB; 64.4% L-Val) has a bioavailability of 100% relative to Val from L-Val (98% L-Val) when fed to weanling pigs. A Val-deficient basal diet containing 0.63% standardized ileal digestible (SID) Val was formulated. Six additional diets were prepared by supplementing the basal diet with 0.08%, 0.17%, or 0.25% L-Val or 0.12%, 0.25%, or 0.37% Val-FB to create experimental diets from both Val sources that contained 0.71%, 0.79%, or 0.87% SID Val. Two hundred twenty-four weaned pigs (6.87 ± 0.64 kg initial BW) were allotted to a randomized complete block design with 7 diets, 4 pigs per pen, and 8 replicate pens per diet. Diets were fed for 20 d. At the conclusion of the experiment, a blood sample from 1 pig per pen was analyzed for blood urea nitrogen (BUN) and plasma free AA. A linear regression model was used to estimate the relative bioavailability (RBV) of Val in Val-FB relative to Val from L-Val. Results indicated that the final BW and ADG were greater (P < 0.01) for pigs fed diets supplemented with Val-FB than pigs fed diets supplemented with L-Val. The ADFI decreased (linear, P ≤ 0.01), whereas G:F increased (linear, P < 0.01) by increasing inclusion of both Val sources in the diets. Regardless of source of dietary Val, BUN values were reduced (linear and quadratic, P < 0.01) as the concentration of Val in the diet increased. Pigs fed diets supplemented with L-Val had increased (linear and quadratic, P ≤ 0.05) concentrations of Val and Arg in plasma, and plasma concentrations of Ile, Leu, Lys, Ala, Cys, and Pro linearly increased (P < 0.05). There was also an increase (linear, P < 0.05) in plasma concentrations of Ile, Leu, Met, Ala, Asp, Cys, and Pro as Val-FB was added to the diets, and the concentration of Val in plasma increased (linear and quadratic, P < 0.05). Using L-Val as the standard, the RBV of Val in Val-FB as determined by ADG, G:F, and final BW was 146%, 135%, and 143%, respectively, with 95% confidence intervals of 99% to 191%, 83% to 187%, and 70% to 217%, respectively. In conclusion, the linear regression estimated a RBV of at least 100% for Val in Val-FB relative to Val from L-Val, and pigs fed diet supplemented with Val-FB had greater final BW, ADG, and G:F than pigs fed diets supplemented with the same amount of Val from L-Val.

Two experiments were conducted to test the hypothesis that a corn-expressed phytase increases growth performance, bone measurements, and nutrient digestibility by young growing pigs, if added to diets that are deficient in Ca and P. In Exp. 1, 60 pigs (initial BW: 10.78 ± 0.67 kg) were randomly allotted to 6 dietary treatments that included a positive control diet (PC; 0.70% total Ca and 0.60% total P) and a negative control diet (NC; 0.50% total Ca and 0.42% total P). Four additional diets were formulated by supplementing the NC diet with 250, 500, 1,000, or 1,500 phytase units (FTU)/kg. Diets were fed for 28 d and the individual BW of pigs on days 1 and 28 were recorded. Fecal samples were collected from days 25 to 27 to calculate apparent total tract digestibility (ATTD) of Ca and P. On the last day of the experiment, all pigs were euthanized, and the left femur was removed and analyzed for ash, Ca, and P. Results indicated that growth performance, ATTD of Ca and P, and bone ash measurements were reduced (P < 0.05) in NC fed pigs compared with PC fed pigs. However, growth performance, ATTD of Ca and P, and bone ash measurements were improved (linear and quadratic, P < 0.05) by including increasing concentrations of phytase to the NC diet. In Exp. 2, experimental procedures were similar to those used in Exp. 1. Forty-eight pigs (initial BW: 11.15 ± 0.85 kg) were randomly allotted to 6 dietary treatments in a 28-d experiment. Treatments included a PC diet, an NC diet, and 4 diets in which 500 or 1,000 FTU/kg of either the corn-expressed phytase or a commercial microbial phytase were added to the NC diet. Pigs fed the NC diet had reduced (P < 0.01) final BW, ADG, G:F, and bone ash concentrations compared with pigs fed the PC diet. When 500 FTU/kg phytase was fed, no differences were observed in growth performance or bone ash measurements between phytase sources, and there were no differences in growth performance among pigs fed 1,000 FTU/kg of either phytase source or the PC diet. However, regardless of concentration or source of phytase, pigs fed the PC diet had greater (P < 0.001) amount of bone ash, bone Ca, and bone P compared with pigs fed phytase diets. In conclusion, the corn-expressed phytase is effective in improving growth performance, Ca and P digestibility, and bone measurements in pigs fed diets that are deficient in Ca and P.

An experiment was conducted to determine the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P in three varieties of hybrid rye and in one source of barley, wheat, corn, and sorghum. The STTD of P in each cereal grain was determined both without and with addition of microbial phytase. In total, 112 growing barrows (13.7 ± 1.3 kg initial BW) were allotted to a randomized complete block design with four blocks of 28 pigs. Pigs were randomly allotted to 14 diets with two replicate pigs per diet in each block, resulting in a total of eight replicate pigs per diet for the four blocks. Each diet contained one of the cereal grains as the sole source of P. There were two diets with each cereal grain with one diet containing no microbial phytase and the other diet containing 1,000 units of microbial phytase per kilogram of diet. In each period, fecal output was collected for 5 d following a 5-d adaptation period according to the marker-to-marker procedure. Among the diets that did not include microbial phytase, one hybrid of rye had greater (P < 0.05) STTD of P than wheat, corn, and sorghum, which is likely a result of the greater intrinsic phytase activity in rye than in the other cereal grains. Without microbial phytase, there was no difference in the STTD of P in the three hybrids of rye and barley. Among the diets containing microbial phytase, there was no difference in STTD of P among the three hybrids of rye, barley, and corn. The STTD of P in the three hybrids of rye with microbial phytase was 61.9%, 70.8%, and 63.0%, respectively. Overall, microbial phytase improved (P < 0.05) the STTD of P in all cereal grains, although the magnitude of the increase in STTD of P differed among the grains.

Two experiments were conducted to test the hypothesis that standardized total tract digestibility (STTD) of Ca and the response to microbial phytase is constant among different sources of Ca carbonate and that the STTD of Ca is constant among different sources of dicalcium phosphate (DCP) when fed to growing pigs. In Exp. 1, 80 pigs (initial BW: 19.0 ± 1.9 kg) were randomly allotted to 10 diets and 2 blocks with 4 pigs per diet in each block. Four sources of Ca carbonate were used, and each source was included in a diet without microbial phytase and a diet with microbial phytase (500 units/kg diet). Two Ca-free diets without or with microbial phytase were also formulated. Feed allowance was 2.7 times the maintenance energy requirement for ME and daily feed allotments were divided into 2 equal meals. The initial 4 d of each period were considered the adaptation period to the diets followed by 4 d of fecal collection using the marker-to-marker procedure. Pigs fed diets containing exogenous phytase had lower (P < 0.05) basal endogenous loss of Ca compared with pigs fed diets containing no phytase. There were no interactions between phytase and source of Ca carbonate. Values for STTD of Ca were greater (P < 0.05) for diets containing microbial phytase (77.3% to 85.4%) compared with diets without exogenous phytase (70.6% to 75.2%), and values for STTD of Ca differed (P < 0.05) among the 4 sources of Ca carbonate. In Exp. 2, 40 pigs (initial BW: 14.9 ± 1.3 kg) were allotted to a completely randomized design with 5 diets and 8 replicate pigs per diet. A basal diet in which all Ca was supplied by Ca carbonate was formulated. Three diets were formulated by adding 3 sources of DCP to the basal diet and a Ca-free diet was also used. Feeding and collection methods were as described for Exp. 1. Results indicated that values for STTD of Ca and ATTD of P were not different among diets, indicating that under the conditions of this experiment, the digestibility of Ca and P in DCP appears to be constant regardless of origin of DCP. In conclusion, use of microbial phytase reduces the basal endogenous loss of Ca and increases Ca digestibility in Ca carbonate. The STTD of Ca varies among sources of Ca carbonate, regardless of phytase inclusion, but that appears not to be the case for the STTD of Ca in different sources of DCP.

Two experiments were conducted to compare the standardized ileal digestibility (SID) of AA by growing pigs in European distillers dried grains with solubles (DDGS) produced from wheat, maize, or wheat–maize mixtures and to test the effect of increasing the inclusion levels of wheat DDGS on growth performance of growing-finishing pigs fed diets balanced for NE and SID Lys. In Exp. 1, 12 barrows (initial BW: 23.0 ± 2.2 kg) were surgically equipped with a T-cannula in the distal ileum and randomly allotted to a replicated 6 × 6 Latin square design with six diets and six periods. Five sources of European DDGS were used: wheat DDGS from 2011, wheat DDGS from 2012, wheat-80 DDGS (80% wheat and 20% maize), wheat-70 DDGS (70% wheat and 30% maize), and maize DDGS. Each diet contained one source of DDGS as the sole source of AA and an N-free diet was used to determine basal endogenous losses of AA. Results indicated that the SID of CP was greater (P < 0.05) in maize DDGS compared with wheat DDGS from 2011, wheat DDGS from 2012, and wheat-70 DDGS. The SID of all indispensable AA except Trp was also greater (P < 0.05) in maize DDGS compared with all other DDGS sources used in this experiment. For Trp, the SID in wheat-80 DDGS, wheat DDGS from 2011, and wheat DDGS from 2012 were not different from maize DDGS, but were greater (P < 0.05) than in wheat-70 DDGS. The SID for all indispensable AA except Ile and Trp in wheat-70 DDGS were not different from the values calculated for wheat DDGS from 2011 and wheat DDGS from 2012, and no differences between SID values for AA in wheat DDGS from 2011 and wheat DDGS from 2012 were observed. In Exp. 2, 36 growing pigs (initial BW: 38.3 ± 1.97 kg) were randomly allotted to one of four dietary treatments (one pig/pen and nine replicate pigs/treatment) in a 2-phase feeding program (35 to 65, and 35 to 105 kg BW). The four dietary treatments included diets containing 0%, 10%, 20%, or 30% wheat DDGS. Results indicated that there was no effect of wheat DDGS on pig growth performance or carcass quality. However, addition of wheat DDGS increased linearly (P < 0.015) the indole concentration in the carcasses of the pigs. In conclusion, the SID of AA in maize DDGS produced in Europe is greater than in European wheat DDGS and DDGS produced from mixtures of wheat and maize, but inclusion of 30% wheat DDGS in diets fed to growing-finishing pigs did not affect growth performance or carcass quality.

Two experiments were conducted to test the hypothesis that different watering options affect the standardized ileal digestibility (SID) of amino acids (AA), apparent total tract digestibility (ATTD) of dry matter (DM) and gross energy (GE), and concentration of net energy (NE) by growing pigs. A corn-soybean meal-based diet was used in both experiments. There were 3 treatments: 1) dry feeder plus a water nipple located outside the feeder, 2) wet-dry feeder with the water nipple inside the feeder, and 3) combined system with a water nipple both inside the feeder and also an outside nipple. In Exp. 1, pigs (n = 6; initial weight = 27.53 kg) that were equipped with a T-cannula in the distal ileum were allotted to the 3 treatments using a replicated 3 × 3 Latin square design with 6 pigs and three 7-d periods. All pigs were fed an N-free diet for an additional period to determine basal endogenous losses of AA. Chromic oxide was added to all diets and ileal digesta were collected according to standard procedures. In Exp. 2, 24 pigs (initial weight = 50.23 kg) were allotted to the 3 treatments using a replicated 3 × 3 Latin square design with 6 chambers (i.e., 4 pigs per chamber) and three 15-d periods. Oxygen consumption and CO2 and CH4 productions were measured during fed and fasting states and fecal and urine samples were collected. In both experiments, pigs were allowed ad libitum access to feed and water. Results indicated that there were no differences among watering options for SID of AA, feed intake, total and fasting heat production, ATTD of DM and GE, or NE in diet. In conclusion, different watering options did not affect the digestibility of AA, DM, and GE and concentration of NE in a corn-soybean meal diet fed to growing pigs.

An N-balance experiment was conducted to test the hypothesis that d-Methionine (d-Met) has the same bioavailability and efficacy as l-Methionine (l-Met) when fed to weanling pigs. A Met-deficient basal diet containing 0.24% standardized ileal digestible (SID) Met was formulated. Six additional diets were formulated by adding 0.036%, 0.072%, or 0.108% d-Met or l-Met to the basal diet, and these diets, therefore, contained 77%, 87%, or 97% of the requirement for SID Met. Fifty-six barrows (10.53 ± 1.17 kg) were housed in metabolism crates and allotted to the seven diets with eight replicate pigs per diet. Feces and urine were collected quantitatively with 7-d adaptation and 5-d collection periods. Blood and tissue samples from pigs fed the basal diet and pigs fed diets containing 0.108% supplemental Met were collected on the last day. Results indicated that N retention (%) linearly increased (P < 0.01) as supplemental d-Met or l-Met increased in diets. Based on N retention (%) as a response, the linear slope-ratio regression estimated the bioavailability of d-Met relative to l-Met to be 101% (95% confidence interval: 57%–146%). The villus height and crypt depth in the jejunum were not affected by the Met level or Met source. Total antioxidant capacity or thiobarbituric acid reactive substance concentrations in plasma or tissue samples from pigs fed the control diet or diets containing 0.108% supplemental d-Met or l-Met were not different. Abundance of mRNA for some AA transporters analyzed in intestinal mucosa of pigs also did not differ. Therefore, it is concluded that d-Met and l-Met are equally bioavailable for weanling pigs.

An experiment was conducted to test the hypothesis that hybrid rye can replace a part of the corn in gestation and lactation diets without negatively affecting sow and litter performance. For each phase, a corn–soybean meal diet and three diets in which hybrid rye replaced 25%, 50%, or 75% of corn were formulated. Two hundred sows were randomly allotted by parity to the four treatments. Results indicated that diet did not affect body weight or average daily gain (ADG) of sows or number of pigs born. The number of pigs weaned, litter weaning weight, and litter ADG increased and then decreased (quadratic, P < 0.05) as hybrid rye in diets increased. Pig mortality and number of crushed pigs tended (quadratic, P < 0.10) to be reduced as hybrid rye was added to the diet. Serum cytokines did not differ among treatments on day 105 of gestation or in pigs on the day of weaning, but interleukin (IL)-4, IL-10, and IL-18 on day 13 of lactation increased and then decreased (quadratic, P < 0.05) as hybrid rye inclusion increased in diets. Milk urea N increased (linear, P < 0.05) as hybrid rye was included in the diet, but no other differences in milk composition were observed. Overall, replacing 25% or 50% of corn with hybrid rye resulted in improved lactation performance, and replacing 75% of corn with hybrid rye resulted in sow and litter performance that was not different from that of sows fed control diets.

An experiment was conducted to test the hypothesis that reducing limestone and monocalcium phosphate in diets for weanling pigs by lowering the concentration of Ca and P or by including microbial phytase in the diet will reduce stomach pH and fecal score and will improve growth performance of pigs. A total of 160 weanling pigs (5.75 ± 1.04 kg) were allotted to four corn-soybean meal-based diets in a completely randomized design with five pigs per pen. Diets for phase 1 (d 1 to 15) were formulated using a 2 × 2 factorial design with 2 concentrations of Ca and P (adequate or deficient levels of total Ca and digestible P) and 2 inclusion levels of phytase (0 or 2,000 units/kg feed). Phytase was assumed to release 0.16% total Ca and 0.11% digestible P. Common diets were fed in phases 2 (d 16 to 21) and 3 (d 22 to 35). Fecal scores were recorded in phase 1 and on d 15, gastric pH was measured and a blood sample and the right femur were collected from one pig per pen. Growth performance data were recorded within each phase. Results indicated that in phase 1, at deficient dietary Ca and P, pigs fed the diet with phytase had greater (P < 0.05) average daily gain (ADG) and gain to feed (G:F) compared with pigs fed the diet without phytase, but in diets with adequate levels of Ca and P, no effect of phytase inclusion was observed (interaction, P < 0.05). Without phytase, pigs fed the diet with deficient Ca and P had reduced (P < 0.05) G:F compared with pigs fed the diet with adequate Ca and P, but if phytase was included, there was no effect of Ca and P on G:F (interaction, P < 0.05). For phases 2 and 3, and from d 1 to 35, no differences among dietary treatments were observed for ADG or G:F. Bone ash was greater (P < 0.05) in pigs fed diets with adequate Ca and P than in pigs fed diets with deficient Ca and P, but no effect of phytase inclusion was observed on bone ash. Concentrations of Ca and P did not affect stomach pH or fecal score, but pigs fed diets with phytase tended (P < 0.10) to have reduced stomach pH and fecal score compared with pigs fed diets without phytase. Pigs fed diets with adequate Ca and P had greater (P < 0.05) albumin in serum than pigs fed the Ca- and P-deficient diets. In conclusion, phytase inclusion in phase 1 diets may reduce diarrhea, but lowering Ca and P does not reduce stomach pH or fecal score and decreases bone ash, although growth performance during the entire weanling period is not affected.

The objective was to test the hypothesis that growth performance and carcass characteristics of pig fed diets containing cold-fermented, low oil distillers dried grains with solubles (DDGS) is not different from that of pigs fed diets containing conventional DDGS regardless of the physical form of the diets. A total of 160 barrows and gilts were used. There were 4 diets, 10 pens per diet, and 4 pigs per pen. Pigs were weaned at 21 d of age and fed a common phase 1 diet that did not contain DDGS during the initial 7 d post-weaning. Pigs were then allotted to the 4 diets that were arranged in a 2 × 2 factorial design with 2 sources of DDGS (cold-fermented and conventional DDGS) and 2 diet forms (meal and pellets). Pigs were fed phase 2 diets from d 7 to 21 and phase 3 diets from d 21 to 43 post-weaning. All diets were based on corn and soybean meal, but phase 2 diets also contained 15% DDGS and phase 3 diets contained 30% DDGS. From d 43, pigs were fed grower diets for 38 d, early finisher diets for 38 d, and late finisher diets for 18 d and these diets also contained 30% DDGS. Feed was provided on an ad libitum basis and daily feed allotments were recorded. Pigs were weighed at the beginning of each phase and at the conclusion of the experiment. On the last day of the experiment, the pig in each pen with a body weight that was closest to the pen average was slaughtered and carcass measurements were determined. Combined results for the 2 nursery phases indicated that feeding meal diets instead of pelleted diets increased (P < 0.001) average daily feed intake and decreased (P < 0.05) gain to feed ratio. However, no differences between the 2 sources of DDGS were observed for the overall growth performance of weanling pigs. For the entire growing-finishing period, the source of DDGS did not affect growth performance, but pigs fed meal diets had reduced (P < 0.001) gain to feed ratio compared with pigs fed the pelleted diets. There were no differences between the 2 sources of DDGS for carcass characteristics. Back fat was greater (P < 0.05) for pigs fed pelleted diets than for pigs fed meal diets. In conclusion, no differences in growth performance or carcass characteristics between pigs fed cold-fermented DDGS and pigs fed conventional DDGS were observed. However, pigs fed pelleted diets had greater gain to feed ratio and greater back fat than pigs fed meal diets.

An experiment was conducted to test the hypothesis that increasing levels of phytase increases mineral digestibility and bone ash by pigs fed diets containing 0.23%, 0.29%, or 0.35% phytate-P. Within each level of phytate, 5 diets were formulated based on corn, soybean meal, and canola meal to contain 0, 500, 1,000, 2,000, or 4,000 phytase units (FTU)/kg of a novel consensus bacterial 6-phytase variant (PhyG). In addition, 3 reference diets were formulated by adding a commercial Buttiauxella phytase (PhyB) at 1,000 FTU/kg to the 3 diets containing no PhyG. A randomized complete block design with 144 pigs (12.70 ± 4.01 kg), 18 diets, and 8 replicate pigs per diet was used. Pigs adapted to diets for 15 d followed by 4 d of fecal collection. Femurs were collected on the last day. Data were analyzed as a 3 × 5 factorial with 3 levels of phytate-P and 5 levels of phytase, and contrast statements were used to compare 1,000 FTU of PhyG with PhyB. Pig was the experimental unit. Diets containing 0.35% phytate-P had reduced (P < 0.01) apparent total tract digestibility (ATTD) of Ca, P, Mg, and K compared with diets containing 0.23% or 0.29% phytate-P, but inclusion of phytase increased (P < 0.01) ATTD of Ca, Na, and K (Table 1). Phytase increased ATTD of P and Mg, but to a greater extent in diets with 0.23 or 0.29% phytate-P than in diets with 0.35% phytate-P (interaction, P < 0.05). Phytase increased bone ash, but to a greater extent if there was 0.35 rather than 0.23 or 0.29% phytate-P in the diets (interaction, P < 0.05). PhyG increased ATTD of P more (P < 0.05) than PhyB. In conclusion, the novel consensus phytase is effective in increasing bone ash and ATTD of Ca, P, Na, Mg and K.

The objective was to determine correlations between individual and total body bone ash to identify the bone that is most representative of total body bone ash. Ten gilts and 10 barrows (BW: 40.8 kg) were allotted to 2 diets. The 2 diets were formulated to contain 60% or 100% of the requirement for standardized total tract digestible (STTD) P and STTD Ca with a STTD Ca:STTD P of 1.90:1, which is believed to maximize bone ash. Body weight and the amount of feed consumed by pigs were recorded on d 14 and 28 and carcass characteristics of all pigs were determined on d 28. Metacarpals, metatarsals, femur, tibia, fibula, ribs, and all other bones from the carcass were collected separately, defatted, and ashed. The statistical model included diet as fixed effect and sex and BW within sex as random effects. Correlation coefficients between total and individual bones were determined. Overall, pigs fed the diet formulated to meet 100% of the requirement for Ca and P had greater (P < 0.05) average daily gain and gain:feed compared with pigs fed the diet with 60% Ca and P, but there was no difference in average daily feed intake (Table 1). There was no effect of dietary Ca and P on carcass characteristics of pigs. Weights of bone ash were greater (P < 0.05) for pigs fed the diet with 100% rather than 60% of the requirement for Ca and P. Correlation coefficients between the weight of total bone ash and the weight of ashed metacarpals, metatarsals, and tibia were greater than 0.950 (P < 0.05), whereas correlation coefficient for femur, fibula, and ribs were less than 0.929 (P < 0.05). In conclusion, metacarpals, metatarsals, and tibia were more representative of total body bone ash compared with femur, fibula, and ribs.

An experiment was conducted to test the hypothesis that spray dried plasma (SDP) increases the standardized ileal digestibility (SID) of CP and AA from other ingredients in diets for young pigs, which may result in a lack of additivity in such diets. Thirty ileal cannulated barrows (body weight: 9.30 ± 0.63 kg) were randomly allotted to a triplicated 10 × 3 Youden square design with 10 diets and three 7-d periods. Diets from four regions were formulated: the U.S.A. [corn-soybean meal (SBM)-based diet], the European Union (corn-wheat-barley-SBM-based diet), Canada (wheat-barley-SBM-fermented SBM-based diet), and Asia (corn-rice-SBM-fermented SBM-based diet). Diets from each region contained 0 or 6% SDP. Differences between measured and predicted SID of CP and AA in diets with SDP were calculated. Data were analyzed using PROC MIXED of SAS as a 2 × 4 factorial with 2 levels of SDP and 4 regions. There was an SDP by region interaction for the measured SID of CP and all AA, except Lys (Table 1). When SDP was added to the U.S.A, the European Union, and Asia diets, the SID of CP and AA was not increased. The SID of CP and AA, except Lys, was greater (P < 0.05) in the Canada diet with SDP than without SDP. The measured SID of CP and AA was consistent with predicted values for the European Union and Asia diets (Table 2). The measured SID of Trp was less (P < 0.05) than predicted for the U.S.A. diet, and the measured SID of CP and all indispensable AA was greater (P < 0.05) than predicted in the Canada diet. In conclusion, addition of 6% SDP to wheat-barley-based diets may increase SID of CP and AA, and therefore, the SID of CP and AA in diets containing SDP may be greater than predicted.

An experiment was conducted to test the hypothesis that increasing concentrations of dietary Val, Ile, or Trp alone or in combination will alleviate negative effects of excess dietary Leu on N balance of growing pigs. Seventy-two barrows (initial body weight: 33.9 ± 2.6 kg) were housed in metabolism crates and randomly assigned to 1 of 8 diets and 3 blocks with 3 pigs per diet in each block in a 12-d experiment. Treatments were arranged in a 2 × 2 × 2 factorial with the main effects of L-Val (0 or 0.1%), L-Ile (0 or 0.1%), and L-Trp (0 or 0.05%) that were added to a basal diet containing corn and a high-protein corn product (48% crude protein; 5.9% Leu). The basal diet contained 1.00 % standardized ileal digestible (SID) Lys and 171% SID Leu:Lys. Data were analyzed using the PROC MIXED of SAS with concentrations of Val, Ile, and Trp, and all interactions as main effects and replicate as a random effect. No 3-way interactions were observed (Table 1). Results indicated that fecal N output increased if Ile was added to diets without added Val, but that was not the case if Val was added (interaction, P < 0.05). Addition of Ile to diets reduced N retention, but N retention increased with Trp addition to diets without Val addition, but not if Trp was added to diets with added Val (interaction, P < 0.05). The biological value of protein increased if Trp was added to diets without addition of Ile, but if Ile was added, Trp addition did not increase the biological value of protein (interaction, P < 0.05). In conclusion, adding Ile to a diet with excess Leu reduced N retention, but if Trp was added alone or in combination with Ile or Val, N retention increased.

The hypothesis that apparent ileal digestibility (AID), basal endogenous losses, and standardized ileal digestibility (SID) of AA are not affected by adding acid to collection containers or bags used to collect ileal digesta from pigs was tested. Twenty-four barrows (initial BW: 77.8 kg) that had a T-cannula installed in the distal ileum were fed diets for three 7-d periods. Corn, soybean meal, and wheat middlings were the sole AA sources in each diet and an N-free diet was also used. Within each period, each of the 4 diets was fed to 6 pigs. Among the 6 pigs, digesta from 3 pigs were collected in bags containing no HCl, whereas 40 mL of 3N HCl was included in the bags used to collect digesta from the remaining 3 pigs. Every other bag collected from each pig was emptied into a container without adding HCl, whereas the remaining bags were added to a container along with 40 mL of 3N HCl for each bag. All digesta were stored at –20 °C immediately after collection. Data were first analyzed using a model that included feed ingredient, HCl in bags, HCl in containers, and all 2-way and 3-way interactions as fixed effects. No 3-way interactions were significant, and data were, therefore, analyzed independently for each diet as a 2 × 2 factorial. Results indicated that there were no interactions between adding HCl to collection bags and to containers, and no effects of adding HCl to collection bags or containers for AID, basal endogenous losses, or SID of most AA were observed (Table 1). In conclusion, if digesta are stored at –20 °C immediately after collection, it is not necessary to add acid to digesta collection bags or collection containers.

The objective was to determine correlations between individual bones and total body bone ash to identify the bone that is most representative of total body bone ash in growing pigs. Twenty growing pigs were allotted to 1 of 2 diets that were formulated to contain 60% or 100% of the requirement for standardized total tract digestible (STTD) P. Both diets had an STTD Ca to STTD P ratio of 1.90:1. Growth performance and carcass weights were determined. Metacarpals, metatarsals, femur, tibia, fibula, 3rd and 4th ribs, and 10th and 11th ribs, and all other bones from the left half of the carcass were collected separately. Each bone was defatted and ashed. Pigs fed the diet containing 100% of required Ca and P had greater (P < 0.05) average daily gain, gain to feed, and ash concentration (%) in total and all individual bones except femur and fibula compared with pigs fed the diet containing 60% of required Ca and P. Calcium and P concentrations in bone ash were not affected by dietary treatments. Weights (g) of bone ash, bone Ca, and bone P were greater (P < 0.05) or tended to be greater (P < 0.10) for pigs fed the diet containing 100% of required Ca and P. Correlation coefficients between the weight of ashed metacarpals, metatarsals, and tibia and the weight of total bone ash were >0.95. In conclusion, metacarpals, metatarsals, and tibia were more representative of total body bone ash compared with other bones.

An experiment was conducted to test the hypothesis that formulating diets for pigs based on a ratio between standardized total tract digestible (STTD) Ca and STTD P instead of total Ca and STTD P does not decrease Ca retention, but increases P utilization. Forty barrows (59.4 ± 3.8 kg) were individually housed in metabolism crates and allotted to four corn-soybean meal-based diets in a randomized complete block design with two blocks and five pigs per diet in each block. Diets were formulated using a 2 × 2 factorial design with two diet formulation principles (total Ca or STTD Ca) and two inclusion levels of microbial phytase (0 or 500 units per kg of feed). Phytase was assumed to release 0.11% STTD P and 0.16% total Ca. Diets were formulated based on requirements for total Ca and STTD P or a ratio between STTD Ca and STTD P of 1.25:1. Diets were fed for 11 d and fecal and urine samples were collected from feed provided from day 6 to day 10. Interactions (P < 0.05) between diet formulation principle and phytase level were observed for Ca intake, Ca in feces, Ca absorbed, Ca retained, P digestibility, P absorbed, and P in urine. Phytase increased (P < 0.05) the digestibility of Ca in both total Ca and STTD Ca diets. Without phytase, Ca intake, Ca in feces, and Ca absorbed was greater (P < 0.05) from pigs fed total Ca diets than from pigs fed STTD Ca diets, but P absorbed, P digestibility, and P in urine was greater (P < 0.05) from pigs fed STTD Ca diets than from pigs fed total Ca diets. However, in the presence of phytase, no differences between diet formulation principles were observed in these variables. Regardless of phytase, Ca in urine was lower (P < 0.05) from pigs fed STTD Ca diets than from pigs fed total Ca diets. There were no differences in Ca retention between pigs fed STTD Ca diets and total Ca diets, but pigs fed total Ca diets retained less (P < 0.05) Ca if diets contained phytase. No differences in P retention were observed between diet formulation principles, but pigs fed non-phytase diets retained more (P < 0.05) P than pigs fed diets with phytase. In conclusion, because diets formulated based on STTD Ca contain less Ca than total Ca diets, pigs fed STTD Ca diets excreted less Ca in urine, but retention of Ca was not affected. Formulating non-phytase diets based on STTD Ca instead of total Ca increased P absorption, which confirms the detrimental effect of excess Ca on P digestibility. However, P retention was not improved if pigs were fed STTD Ca diets.

The objective was to test the hypothesis that there is no effect of origin or processing procedure on the standardized ileal digestibility (SID) of amino acids (AA) and crude protein (CP) in sunflower co-products. Six sources of sunflower meal (SFM) and 1 source of sunflower expellers (SFE) were obtained from Ukraine, Italy, Hungary, and the U.S. Each source of SFM or SFE was the only source of CP and AA in 1 diet and an N-free diet was also used for a total of 8 diets. Eight barrows (body weight: 28.5 ± 2.4 kg) had a T-cannula installed in the distal ileum and were allotted to 1 of the 8 diets using an 8 × 8 Latin square design with 8 periods. The Lys:CP ratio in the 6 sources of SFM ranged from 3.10 to 3.96% with CP concentrations ranging from 27.34 to 36.75%. Crude protein in SFE was 26.87% and the Lys:CP ratio was 3.51%. Concentrations of acid hydrolyzed ether extract in the 6 sources of SFM ranged from 0.60 to 3.11%, but SFE contained 8.77%. Results indicated that the SID of CP was lower (P < 0.05) in SFM from Hungary compared with all other sources of SFM except for 1 of the sources from Ukraine. There were no differences in the SID of Lys, Met, and Trp among sources of SFM, but for most of the remaining indispensable AA, the SFM from Hungary had less (P < 0.05) SID than the other sources. However, only few differences in SID of indispensable AA were observed among the other sources of SFM, but the SID of CP and all AA except Trp was greater (P < 0.05) in SFE compared with SFM. In conclusion, there were only few differences in the SID of the first limiting AA among SFM obtained from Ukraine, Hungary, Italy, and the U.S., but the SID of CP and AA was greater in SFE than in SFM indicating that processing of sunflower seeds influence the nutritional value.

An experiment was conducted to test the hypothesis that inclusion of Cu oxide (Cu2O) in diets for growing–finishing pigs improves body weight (BW) and bone mineralization, and reduces accumulation of Cu in the liver compared with pigs fed diets containing Cu sulfate (CuSO4). Two hundred growing pigs (initial BW: 11.5 ± 0.98 kg) were allotted to a randomized complete block design with 2 blocks of 100 pigs, 5 dietary treatments, 5 pigs per pen, and a total of 8 pens per treatment. Treatments included the negative control (NC) diet that contained 20 mg Cu/kg, and 4 diets in which 125 or 250 mg Cu/kg from CuSO4 or Cu2O were added to the NC diet. The experiment was divided into 4 phases and concluded when pigs reached market weight. Pig weights were recorded on day 1 and at the end of each phase and feed provisions were recorded throughout the experiment. On the last day of phases 1 and 4, 1 pig per pen was sacrificed to obtain samples of liver and spleen tissue, and the right metacarpal was collected. Results indicated that pigs fed diets containing 250 mg Cu/kg from CuSO4 had greater BW at the end of phases 1 and 2 than pigs fed NC diets. Pigs fed diets containing 250 mg Cu/kg from Cu2O had greater (P < 0.05) BW at the end of phases 1, 2, 3, and 4 compared with pigs fed NC diets, and these pigs also had greater BW at the end of phases 3 and 4 than pigs fed all other diets. Pigs fed the diets with 250 mg Cu/kg tended to have greater (P < 0.10) feed intake than pigs fed the NC diet at the end of phase 2, and for the overall experimental period, pigs fed diets containing 250 mg Cu/kg from Cu2O had greater (P < 0.05) feed intake than pigs on all other treatments. However, no differences in gain:feed ratio were observed among treatments. Copper accumulation in liver and spleen increased with Cu dose, but at the end of phase 1, pigs fed 250 mg Cu/kg from CuSO4 had greater (P < 0.05) Cu concentration in liver and spleen than pigs fed 250 mg Cu/kg from Cu2O. Pigs fed diets containing 250 mg Cu/kg from Cu2O had greater (P < 0.05) quantities of bone ash and greater (P < 0.05) concentrations of Ca, P, and Cu in bone ash than pigs fed NC diets or the 2 diets containing CuSO4, but Zn concentration in bone ash was less (P < 0.05) in pigs fed diets containing 250 mg Cu/kg from Cu2O. To conclude, supplementing diets for growing pigs with Cu2O improves growth performance and bone mineralization with less Cu accumulation in liver compared with pigs fed diets containing CuSO4.

Three experiments were conducted to test the hypothesis that standardized ileal digestibility (SID) of amino acids (AA) and digestible energy (DE) and metabolizable energy (ME) in a new source of corn protein are greater than in corn distillers dried grains with solubles (DDGS) and that corn protein may be included in diets for weanling pigs. In experiment 1, the SID of AA was determined in two sources of DDGS (DDGS-1 and DDGS-2) and in corn protein. Results indicated that SID of most AA was greater (P < 0.05) in DDGS-2 and corn protein than in DDGS-1, but corn protein contained more digestible AA than both sources of DDGS. In experiment 2, the DE and ME in corn, the two sources of DDGS, and corn protein were determined. Results demonstrated that DE (dry matter basis) in corn protein was greater (P < 0.05) than in corn, but ME (dry matter basis) was not different between corn and corn protein. However, DE and ME in corn (dry matter basis) were greater (P < 0.05) than in DDGS-1 and DDGS-2. In experiment 3, 160 weanling pigs were allotted to four treatments in phases 1 and 2 and a common diet in phase 3. Corn protein was included at 5% to 10% in phases 1 and 2 at the expense of plasma protein and enzyme-treated soybean meal. Results indicated that although differences in average daily gain and gain to feed ratio were observed in phase 1, no differences among treatments were observed for the overall experimental period. In conclusion, the concentration of digestible AA is greater in corn protein than in DDGS; DE and ME in corn protein are also greater than in DDGS; and up to 10% corn protein may be included in phase 1 and phase 2 diets for weanling pigs.

An experiment was conducted to test the hypothesis that reducing crude protein (CP) in starter diets for pigs reduces post-weaning diarrhea and improves intestinal health. In total, 180 weanling pigs were allotted to 3 diets containing 22, 19, or 16% CP. Fecal scores were visually assessed every other day. Blood samples were collected from 1 pig per pen on days 1, 6, 13, 20, and 27, and 1 pig per pen was euthanized on day 12. Results indicated that reducing dietary CP reduced (P < 0.01) overall average daily gain, gain to feed ratio, final body weight, and fecal scores of pigs. Pigs fed the 16% CP diet had reduced (P < 0.01) serum albumin compared with pigs fed other diets. Blood urea nitrogen, haptoglobin, interleukin-1β, and interleukin-6 concentrations in serum were greatest (P < 0.01) on day 13, whereas tumor necrosis factor-α and interleukin-10 concentrations were greatest (P < 0.01) on day 6. Villus height in the jejunum increased (P < 0.05) and crypt depth in the ileum was reduced (P < 0.01) if the 19% CP diet was fed to pigs compared with the 22% CP diet. A reduction (P < 0.05) in mRNA abundance of interferon-γ, chemokine ligand 10, occludin, trefoil factor-2, trefoil factor-3, and mucin 2 was observed when pigs were fed diets with 16% CP. In conclusion, reducing CP in diets for weanling pigs reduces fecal score and expression of genes associated with inflammation.

Determine digestible indispensable amino acid score (DIAAS) for animal- and plant-based burgers and test the hypothesis that DIAAS calculated for a burger and a burger bun is additive in a combined meal.Ten ileal cannulated gilts were fed experimental diets for six 9-d periods with ileal digesta being collected on d 8 and 9 of each period. Six diets contained a burger (i.e., 80% lean beef, 93% lean beef, 80% lean pork, Impossible Burger, or Beyond Burger) or a burger bun as the sole source of crude protein and amino acids. Three additional diets were based on a combination of the bun and 80% beef, pork, or Impossible Burger. A nitrogen-free diet was also used. The DIAAS for all ingredients and mixed meals was calculated for children from 6 months to 3 years and for individuals older than 3 years, and DIAAS for combined meals was predicted from individual ingredient DIAAS.The 93% lean beef and the pork burgers had greater (P 0.05) DIAAS than the plant-based burgers for both age groups. The 80% lean beef burger had greater (P 0.05) DIAAS than the plant burgers for children from 6 months to 3 years, and greater (P 0.05) DIAAS than the Beyond Burger for individuals older than 3 years. There were no differences between the measured and predicted DIAAS.The protein quality of animal-based burgers is greater than that of plant-based burgers. However, for individuals older than 3 years, the Impossible Burger has comparable protein quality to the 80% lean beef burger. The DIAAS obtained from individual foods is additive in mixed meals.

An experiment was conducted to test the hypothesis that the requirement for Ca expressed as a ratio between standardized total tract digestible (STTD) Ca and STTD P obtained in short-term experiments may be applied to pigs fed diets without or with microbial phytase from 11 to 130 kg. In a 5-phase program, 160 pigs (body weight: 11.2 ± 1.8 kg) were randomly allotted to 32 pens and 4 corn–soybean meal-based diets in a 2 × 2 factorial design with 2 diet formulation principles (total Ca or STTD Ca), and 2 phytase inclusion levels (0 or 500 units/kg of feed) assuming phytase released 0.11% STTD P and 0.16% total Ca. The STTD Ca:STTD P ratios were 1.40:1, 1.35:1, 1.25:1, 1.18:1, and 1.10:1 for phases 1 to 5, and STTD P was at the requirement. Weights of pigs and feed left in feeders were recorded at the end of each phase. At the conclusion of phase 1 (day 24), 1 pig per pen was euthanized and a blood sample and the right femur were collected. At the end of phases 2 to 5, a blood sample was collected from the same pig in each pen. At the conclusion of the experiment (day 126), the right femur of 1 pig per pen was collected and carcass characteristics from this pig were measured. No interactions were observed between diet formulation principle and phytase inclusion for growth performance in any phase and no differences among treatments were observed for overall growth performance. Plasma Ca and P and bone ash at the end of phase 1 were also not influenced by dietary treatments. However, on day 126, pigs fed nonphytase diets formulated based on total Ca had greater bone ash than pigs fed STTD Ca-based diets, but if phytase was used, no differences were observed between the 2 formulation principles (interaction P < 0.05). At the end of phases 2 and 3, pigs fed diets without phytase had greater (P < 0.05) plasma P than pigs fed diets with phytase, but no differences were observed at the end of phases 4 and 5. A negative quadratic effect (P < 0.05) of phase (2 to 5) on the concentration of plasma Ca was observed, whereas plasma P increased (quadratic; P < 0.05) from phases 2 to 5. However, there was no interaction or effect of diet formulation principle or phytase inclusion on any carcass characteristics measured. In conclusion, STTD Ca to STTD P ratios can be used in diet formulation for growing-finishing pigs without affecting growth performance or carcass characteristics and phytase inclusion ameliorates bone resorption caused by low dietary Ca and P.

The objective of this study was to test the hypothesis that growth performance and carcass characteristics of pigs fed diets containing cold-fermented, low oil distillers dried grains with solubles (DDGS) is not different from that of pigs fed diets containing conventional DDGS regardless of the physical form of the diets. A total of 160 barrows and gilts were used. There were 4 diets, 10 pens per diet, and 4 pigs per pen. Pigs were weaned at 21 d of age and fed a common phase 1 diet that did not contain DDGS during the initial 7 d post-weaning. Pigs were then allotted to the four diets that were arranged in a 2 × 2 factorial design with two sources of DDGS (cold-fermented and conventional DDGS) and two diet forms (meal and pellets). Pigs were fed phase 2 diets from day 7 to 21 and phase 3 diets from day 21 to 43 post-weaning. All diets were based on corn and soybean meal, but phase 2 diets also contained 15% DDGS and phase 3 diets contained 30% DDGS. From day 43, pigs were fed grower diets for 38 d, early finisher diets for 38 d, and late finisher diets for 18 d and these diets also contained 30% DDGS. Feed was provided on an ad libitum basis and daily feed allotments were recorded. Pigs were weighed at the beginning of each phase and at the conclusion of the experiment. On the last day of the experiment, the pig in each pen with a body weight that was closest to the pen average was slaughtered and carcass measurements were determined. Combined results for the two nursery phases indicated that feeding meal diets instead of pelleted diets increased (P < 0.001) average daily feed intake and decreased (P < 0.05) gain to feed ratio (G:F). However, no differences between the two sources of DDGS were observed for the overall growth performance of weanling pigs. For the entire growing-finishing period, the source of DDGS did not affect growth performance, but pigs fed meal diets had reduced (P < 0.001) G:F compared with pigs fed the pelleted diets. There were no differences between the two sources of DDGS for carcass characteristics. Back fat was greater (P < 0.05) for pigs fed pelleted diets than for pigs fed meal diets. In conclusion, no differences in growth performance or carcass characteristics between pigs fed cold-fermented DDGS and pigs fed conventional DDGS were observed. However, pigs fed pelleted diets had greater G:F and greater back fat than pigs fed meal diets.

Objective: The hypothesis was that apparent ileal digestibility (AID), basal endogenous losses, and standardized ileal digestibility (SID) of amino acids (AA) are not affected by adding acid to collection containers or bags used to collect ileal digesta from pigs.Methods: Twenty-four growing barrows (initial body weight: 77.8±4.5 kg) that were fitted with a T-cannula in the distal ileum were fed diets for three 7-d periods. An N-free diet and 3 diets containing corn, soybean meal, or wheat middlings as the sole source of AA were used. Within each period, each of the 4 diets were fed to 6 pigs. Among the 6 pigs, digesta from 3 pigs were collected in bags containing no HCl, whereas 40 mL of 3 N HCl was included in the bags used to collect digesta from the remaining 3 pigs. Every other bag collected from each pig was emptied into a container without adding HCl, whereas the remaining bags were added to a container along with 40 mL of 3 N HCl for each bag. All digesta were stored at –20°C immediately after collection. Data were analyzed using a model that included feed ingredient, HCl in bags, HCl in containers, and all 2-way and 3-way interactions as fixed effects. No 3-way interactions were significant, and data were, therefore, reanalyzed independently for each diet as a 2×2 factorial.Results: There were no interactions between adding HCl to collection bags and to containers, and no effects of adding HCl to collection bags or containers for AID, basal endogenous losses, or SID of most AA were observed.Conclusion: It is not necessary to add acid to digesta collection bags or collection containers if ileal digesta are stored at –20°C immediately after collection.

An experiment was conducted to test the hypothesis that feed flavor and feed sweetener improve growth performance of weanling pigs. One hundred twenty-eight pigs (5.97 ± 0.55 kg) were allotted to 4 treatments with 4 pigs per pen and 8 pen replicates per diet. A 3-phase feeding program was used. In all phases, a control diet was formulated based on corn and soybean meal, and 3 additional diets were formulated by adding feed flavor (500 mg/kg), feed sweetener (150 mg/kg), or their combination to the control diet. Fecal scores were visually assessed using a score from 1 to 5 (1 = normal feces to 5 = watery diarrhea). Experimental diets were fed to pigs for 6 wk. Data were analyzed using SAS with pen as the experimental unit. Diet was the fixed effect and replicate was the random effect. Results indicated that overall average daily feed intake (ADFI) was greater (P < 0.05) and overall average daily gain (ADG) tended to be greater (P < 0.10) for pigs fed the diet containing feed sweetener compared with pigs fed the control diet (Table 1). The observed improvements in ADG and ADFI also resulted in greater (P < 0.05) final body weight for pigs fed the feed sweetener diet compared with pigs fed the control diet. Inclusion of feed flavor, feed sweetener, or the combination of feed flavor and sweetener in diets did not affect fecal scores of pigs, but inclusion of feed flavor resulted in reduced overall frequency of diarrhea (P = 0.05). In conclusion, supplementation of feed sweetener improved growth performance and feed flavor supplementation to diets ameliorated post-weaning diarrhea of weanling pigs from d 1 to 42.

Feed phosphates are included in swine diets to meet the requirements of P. Two products are predominantly used for this purpose, commercial monocalcium phosphate (MCP) and dicalcium phosphate (DCP). Theoretically, pure MCP should contain 26.5% P but commercial sources of MCP contain around 21 % P. The reason there is less P in commercial sources is that these sources are contaminated with calcium carbonate and other minerals. In addition, feed grade phosphates called MCP in reality is a mixture of MCP and DCP, which also contributes to the reduced P. To determine the complete composition of commercial MCP, seven sources of MCP were procured. All sources were analyzed for most common minerals that may be present in feed phosphates (Table 1) Results indicate that the composition of minerals is relatively stable among the different sources of MCP, indicating that the process to produce feed grade phosphates does not result in much variability. However, none of the commercial feed grade phosphates contained close to 26.5% P, which would be expected in a pure source.

An experiment was conducted to test the hypothesis that Cu hydroxychloride (IntelliBond CII, Micronutrients, LLC, Indianapolis, IN) improves growth performance by upregulating the mRNA transcription of genes involved in lipid metabolism of pigs. Thirty-two pigs (15.05 ± 0.98 kg) were allotted to 2 dietary treatments with 2 pigs per pen for a total of 8 replicate pens per treatment. Pigs were fed a control diet based on corn, soybean meal, and distillers dried grains with solubles that included Cu to meet the requirement. A second diet was formulated by adding 150 mg Cu/kg from Cu hydroxychloride to the control diet. On the last day of the experiment, one pig per pen was sacrificed and samples from liver, skeletal muscle, and subcutaneous adipose tissue were collected to analyze relative mRNA abundance of genes involved in lipid metabolism. Data were analyzed using SAS with pen as the experimental unit. Diet was the fixed effect and replicate was the random effect. Results indicated that overall average daily gain and gain:feed were greater (P < 0.05) for pigs fed the diet containing Cu hydroxychloride compared with pigs fed the control diet (Table 1). Pigs fed the diet supplemented with Cu hydroxychloride had increased (P < 0.05) abundance of cluster of differentiation 36 in liver and increased (P < 0.05) abundance of fatty acid binding protein 4 and lipoprotein lipase in subcutaneous adipose tissue. Inclusion of Cu hydroxychloride also tended to increase (P < 0.10) abundance of fatty acid binding protein 1, peroxisome proliferator-activated receptor alpha, and carnitine palmitoyl transferase 1 B in liver, skeletal muscle, and subcutaneous adipose tissue, respectively. In conclusion, supplementation of Cu hydroxychloride to the control diet improved growth performance and may affect signaling pathways associated with lipid metabolism by upregulating abundance of some genes involved in post-absorptive metabolism of lipids.

An experiment was conducted to test the hypothesis that hybrid rye can replace corn in gestation and lactation diets without negatively affecting sow and litter performance. For gestation and lactation, a corn-soybean meal control diet and 3 additional diets in which hybrid rye replaced 25, 50, or 75% of corn were formulated. Sows were randomly allotted by parity to treatments, with 45 replicate sows per treatment. Sows were individually housed for the duration of the experiment. Sow BW were recorded on d 7 and d 105 of gestation, as well as within 24 h after farrowing and on the day of weaning (approximately d 20 of lactation). Number and weights of live born, still born, and mummified piglets were determined within 24 h of farrowing. Data related to piglet mortality were analyzed using SAS Proc Glimmix with binomial distribution, whereas all other data were analyzed using Proc Mixed. The statistical models included the fixed effects of diet and parity. Diet did not influence sow BW or sow ADG at any point in the experiment (Table 1). Diet did not affect number or weights of total, live, or still born pigs, but there was an increase and then a reduction in the number of pigs weaned, litter wean weight, and litter ADG as the inclusion of hybrid rye in the diets increased (quadratic, P < 0.05). Piglet mortality, as well as the proportion of piglets crushed by sows, tended (P < 0.10) to be quadratically reduced as hybrid rye was added to the diet. In conclusion, replacing corn with hybrid rye in gestation and lactation diets had no effect on sow BW changes nor on number or birthweights of piglets, and overall, diets with 25% and 50% corn replacement rate with rye resulted in improved sow lactation performance.

Reducing dietary CP with crystalline AA supplementation has been proposed as a nutritional strategy to control post-weaning diarrhea in response to global concerns about negative effects of sub-therapeutic use of antibiotics. One hundred eighty weaned pigs (5.53 ± 0.88 kg) were randomly allotted to 3 treatments with 12 replicate pens per treatment for 28 d. Treatments included antibiotic-free, corn-soybean meal diets containing 22% and 19% CP, adequate in AA, and a 16% CP diet that provided AA below the requirement. Daily feed provisions and pig weights were recorded weekly. Fecal scores were assessed every other day. Blood samples were collected on d 1, 6, 13, 20, and 27 and 1 pig per pen was euthanized on d 12. Data for growth performance, fecal scores, and intestinal pH were analyzed by contrast statements and data for blood characteristics were analyzed using repeated measures. Results indicated that reducing dietary CP linearly (P ≤ 0.05) reduced overall ADG, G:F, body weight, and fecal scores of pigs. Reduction in dietary CP resulted in greater reduction in BUN after d 13 (treatment × day interaction, P ≤ 0.05). Total protein, albumin, and vitamin A and E in serum were lowest (P ≤ 0.05) on d 13, and pigs fed 16% CP had reduced (P ≤ 0.05) albumin compared with pigs fed other diets. The pH in the ileum was reduced (P ≤ 0.05) as dietary CP decreased but pH in the colon of pigs fed 19% CP was the lowest (P < 0.05) at d 13. In conclusion, reducing CP to 19% and 16% in antibiotic-free diets for weanling pigs reduces fecal score without impairing the growth performance during the first 14 d after weaning. However, additional strategies are needed to maintain growth performance during the next two weeks.

Two experiments were conducted to test the hypothesis that standardized ileal digestibility (SID) of AA by growing pigs is not influenced by dietary AA. In Exp. 1, thirty cannulated pigs (BW:31.4 ± 3.9 kg) were allotted to 5 diets. Four diets were formulated to contain 4.7 to 30.4% CP, by including 10, 30, 50, or 70% soybean meal. An N-free diet was used to determine the basal endogenous losses of CP and AA. The model included diet as a fixed variable and polynomial contrasts were used to test linear and quadratic effects of dietary AA. The SID of CP, Lys, Phe, and Thr decreased linearly (P < 0.05) as dietary AA increased (Table 1). However, this effect was primarily a result of the SID of AA in the diet containing 30.4% CP and the SID of CP and most AA was not affected by dietary AA if diets contained 4.7 to 22.1% CP. In Exp. 2, twenty-four cannulated pigs (BW:22.8 ± 1.7 kg) were used. Pigs were allotted to a quadruplicated 6 × 2 Youden square design with 6 diets and 2 periods. Five diets were formulated to contain 6.8 to 31.8% CP, by including 10, 20, 30, 40, or 50% soy protein concentrate. An N-free diet was also used. Data were analyzed as for Exp. 1. The SID of His and Lys decreased quadratically (P < 0.05) with increased dietary AA (Table 2). However, if dietary CP was 26.6% or less, no effect of dietary AA on SID of CP and most indispensable AA was observed. In conclusion, the SID of most AA is not influenced by dietary AA if dietary CP does not exceed around 26%. Hence, the SID of AA in feed ingredients may be determined in diets containing AA below, at, or slightly above requirements without impacting results.

An experiment was conducted to test the hypothesis that inclusion of an enzyme premix (xylanase and cellulase) in diets based on corn or sorghum and fed to growing pigs improves the apparent total tract digestibility (ATTD) of energy and total dietary fiber (TDF) and concentration of digestible energy (DE) and metabolizable energy (ME). Two basal diets based on corn and soybean meal or sorghum and soybean meal were formulated. Four additional diets were formulated by adding 40% distillers dried grains with solubles (DDGS) or 40% wheat middlings to each of the 2 basal diets. Each of these 6 diets were formulated either without or with an enzyme premix that contained xylanase and cellulase. A total of 144 pigs (61.7 ± 5.3 kg) were allotted to a randomized complete block design with 12 diets and 12 replicate pigs per diet. Pigs were housed individually and adapted to the diets for 12-d, then moved to metabolism crates and after 4 d, urine and feces were collected for 5 d. Data were analyzed as 2 × 2 × 3 factorial with 2 types of diets, two enzymes treatments, and three by-product inclusions. The pig was the experimental unit. The ATTD of gross energy (GE), and DE and ME improved (P < 0.01) if enzymes were added to the diets regardless of the grain source or by-product inclusion (Table 1). No effect of enzymes on ATTD of TDF was observed, ATTD of TDF was greater if DDGS rather than wheat middlings was added to the corn diet (grain source × by-product interaction, P < 0.05). In conclusion, addition of enzymes may have the potential to improve the ATTD of GE, and DE and ME in mixed diets based on corn or sorghum and both without and with inclusion of DDGS or wheat middlings. 3Enz = enzyme premix supplied by ADM Animal Nutrition, Quincy, IL, USA.

Corn, soybean meal, DDGS and extracted lipids are common staple ingredients in swine feed. Purpose-based proportioning of these ingredients in the formulation can achieve distinct levels of net energy (NE) and amino acids (AA), as well as fiber and micronutrients, in feed. In this study, diets were formulated using a 2 × 2 factorial design on NE and AA, in which the diet with high AA (HAA) had more soybean meal than the diet with low AA (LAA), while the diet with high NE (HNE) had more choice white grease and less DDGS than the diet with low net energy (LNE). Total 160 pigs (4 pigs/pen) were fed for 90 days under a three-phase feeding program. In each phase, 4 groups of pigs (10 pens/group) were fed four respective diets of HNE+HAA, HNE+LAA, LNE+HAA, and LNE+LAA. On day 90, body weights were recorded to calculate ADG, and cecal digesta were collected for LC-MS-based metabolomic analysis and 16S RNA sequencing-based microbiomic analysis. The one-way ANOWA of ADG data showed that ADG was increased by NE (p < 0.05), but not by AA. Multivariate analysis (MVA) of metabolomics and microbiomics data also showed that NE, but not AA, caused apparent changes in the metabolome and microbiome of cecal digesta. The metabolites and microbes connecting NE level with ADG, including citrulline, hexadecenoic acid, Bacteroides stercoris, and Ruminococcus bromii, were identified through examining the markers that separate HNE and LNE feedings in the MVA models of cecal metabolome and microbiome as well as the markers that were significantly correlated with ADG in the Pearson correlation analysis. Overall, the results from this study revealed specific metabolomic and microbiomic changes associated with dietary NE level and growth performance, which could serve as a foundation for further analysis on the metabolic and prebiotic functions of feed ingredients.

The objective of this experiment was to test if standardized ileal digestibility (SID) of AA in a new source of high-protein distillers dried grains with solubles (HP-DDGS) is greater than in conventional distillers dried grains with solubles (DDGS-CV). Nine barrows (initial BW: 67.2 ± 6.4 kg) with a T-cannula in the distal ileum were allotted to a triplicate 3 × 3 Latin Square design with 3 diets and 3 periods. Two diets included HP-DDGS or DDGS-CV as the sole source of CP and AA. A nitrogen-free diet was used to determine basal endogenous losses of CP and AA. The statistical model included ingredient as fixed effect and square, period, and animal as random effects. Results indicated that that HP-DDGS contained more CP and AA compared with DDGS-CV (Table 1). The SID of all AA in HP-DDGS were greater (P < 0.001) compared with DDGS-CV with the exception that the SID of Pro was not different between the 2 sources of DDGS. The greater concentrations of AA and values for SID of AA in HP-DDGS indicate that this new DDGS source has a very high quality and may be a great source of digestible AA in diets fed to pigs.

Three experiments were conducted to test the hypothesis that the standardized ileal digestibility (SID) of amino acids (AA), concentrations of digestible energy (DE) and metabolizable energy (ME), and the standardized total tract digestibility (STTD) of P in a new source of fermented soybean meal (Fermex 200) are greater than in conventional soybean meal (SBM-CV). In experiment 1, 9 barrows (initial body weight: 9.17 ± 1.03 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to a triplicated 3 × 3 Latin square design. A nitrogen-free diet and 2 diets that contained cornstarch and SBM-CV or Fermex 200 as the sole source of crude protein (CP), and AA were formulated. Results indicated that there were no difference between SBM-CV and Fermex 200 for SID of CP and AA. In experiment 2, 24 growing pigs (initial body weight: 14.19 ± 1.18 kg) were housed individually in metabolism crates. Pigs were allotted to a corn-based diet or 2 diets that contained corn and SBM-CV or corn and Fermex 200. Feces and urine samples were collected using the marker-to-marker approach with 5-d adaptation and 4-d collection periods. Results indicated that the concentration of DE and ME in Fermex 200 were not different from DE and ME in SBM-CV. In experiment 3, 40 barrows (initial body weight: 11.01 ± 1.38 kg) were allotted to 1 of 4 diets with 10 replicate pigs per diet. Four diets were formulated to contain Fermex 200 or SBM-CV and either 0 or 1,000 units/kg of microbial phytase. Pigs were housed individually in metabolism crates. Fecal samples were collected as explained for experiment 2. Results indicated that the STTD of P in Fermex 200 was greater (P < 0.01) than in SBM-CV, but the addition of microbial phytase to the diets increased the ATTD and STTD of P in SBM-CV, but not in Fermex 200 (interaction; P < 0.01). In conclusion, the SID of AA and concentrations of DE and ME in Fermex 200 were not different from values determined for SBM-CV, but the STTD of P was greater in Fermex 200 than in SBM-CV if microbial phytase was not added to the diet.

Diets based on high levels of corn protein have elevated concentrations of Leu, which may negatively affect N retention in pigs. An experiment was, therefore, conducted to test the hypothesis that Ile and Val supplementation may overcome the detrimental effects of excess dietary Leu on N balance and metabolism of branched-chain amino acids (BCAA) in growing pigs. A total of 144 barrows (initial body weight: 28.5 kg) were housed in metabolism crates and randomly assigned to 1 of 18 dietary treatments. The basal diet contained 0.98% standardized ileal digestible (SID) Lys and had SID Leu, Val, and Ile ratios to SID Lys of 100%, 60%, and 43%, respectively. Crystalline l-Leu (0% or 2.0%), l-Ile (0%, 0.1%, or 0.2%), and l-Val (0%, 0.1%, or 0.2%) were added to the basal diet resulting in a total of 18 dietary treatments that were arranged in a 2 × 3 × 3 factorial. Urine and fecal samples were collected for 5 d after 7 d of adaptation. Blood, skeletal muscle, and liver samples were collected at the conclusion of the experiment. There were no three-way interactions among the main effects. Excess Leu in diets reduced (P < 0.05) N retention and biological value of protein and increased (P < 0.001) plasma urea N (PUN), but PUN was reduced (P < 0.05) as dietary Val increased. Concentrations of Leu in the liver were greater (P < 0.001) in pigs fed excess Leu diets than in pigs fed adequate Leu diets, but concentrations of BCAA in muscle were greater (P < 0.05) in pigs fed low-Leu diets. Increasing dietary Ile increased (P < 0.001) plasma-free Ile and plasma concentration of the Ile metabolite, α-keto-β-methylvalerate, but the increase was greater in diets without excess Leu than in diets with excess Leu (interaction, P < 0.001). Plasma concentrations of Val and the Val metabolite α-keto isovalerate increased (P < 0.001) with increasing dietary Val in diets with adequate Leu, but not in diets with excess Leu (interaction, P < 0.001). Increasing dietary Leu increased (P < 0.001) plasma-free Leu and plasma concentration of the Leu metabolite, α-keto isocaproate (KIC). In contrast, increased dietary Val reduced (P < 0.05) the plasma concentration of KIC. In conclusion, excess dietary Leu reduced N retention and increased PUN in growing pigs, but Val supplementation to excess Leu diets may increase the efficiency of amino acid utilization for protein synthesis as indicated by reduced PUN.