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The DE and ME content (Exp. 1) as well as the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of essential AA (EAA; Exp. 2) were compared between Chinese corn and U.S. sorghum. The effects of U.S. sorghum as a potential substitute for Chinese corn on growth performance of 114 weaned pigs (8.8 ± 1.0 kg BW; Exp. 3) and 60 growing pigs (23.4 ± 1.6 kg BW; Exp. 4) were evaluated, and the effect of protease supplementation on N utilization was determined in sorghum-based diets fed to growing pigs (Exp. 4). In Exp. 1, there was no difference in DE and ME content between corn and sorghum. In Exp. 2, the AID and SID of most EAA and the concentrations of standardized ileal digestible Lys, Met, Thr, and His were less in sorghum than in corn (P < 0.05). In Exp. 3, there was no difference in ADG and ADFI among treatments during the experimental period. The G:F and apparent total tract digestibility (ATTD) of CP was decreased for pigs fed diets with sorghum in the first 2 wk (P < 0.05) and for pigs fed diets containing 60% sorghum in the following 2 wk (P < 0.05). The fecal score for pigs fed diets with sorghum, regardless of the substitute level, was less (P < 0.05) or tended to be less (P = 0.086) than that for pigs fed diets containing 60% corn. In Exp. 4, no differences were observed in ADG and ADFI overall among pigs fed diets based on corn and soybean meal (CSBM) or sorghum and soybean meal (SSBM). Pigs fed CSBM or SSBM with protease supplementation had greater (P < 0.05) or tended to have greater (P = 0.062) G:F than pigs fed SSBM. Compared with CSBM, SSBM increased fecal N excretion by more than 25% and decreased the ATTD of CP by more than 7% during the whole experiment (P < 0.05). Protease supplementation reduced fecal N excretion by more than 12% and increased ATTD of CP by more than 6% (P < 0.05). In conclusion, based on optimal G:F and CP digestibility, diets for weaned pigs should contain less than 20% sorghum during the first 2 wk and no more than 40% during the subsequent 2 wk after weaning. Sorghum used as an alternative energy source for corn in diets fed to growing pigs decreases CP utilization by increasing manure N output, which might be partially offset by protease supplementation. [ABSTRACT FROM AUTHOR]

This experiment used indirect calorimetry to determine the net energy ( NE) content of five corn distillers dried grains with solubles (corn DDGS) containing different oil levels and to compare the NE obtained using indirect calorimetry with that calculated using previously published prediction equations. There were two samples of high-oil DDGS, one sample of medium-oil DDGS and two samples of low-oil DDGS. Twelve barrows (initial BW of 32.8 ± 2.0 kg) were used in a repeated 3 × 6 Youden square design with three periods and six diets. The diets were comprised of a corn-soybean meal basal diet and five diets containing 29.25% of one of the corn DDGS added at the expense of corn and soybean meal. During each period, the pigs were individually housed in metabolism crates for 16 days which included 7 days for adaption to feed and environmental conditions. On day 8, the pigs were transferred to respiration chambers and fed one of the six diets at 2300 kJ ME/kg BW0.6/day. Faeces and urine were collected from day 9 to 13 and heat production (HP) was also measured. From day 14 to 15, the pigs were fed 893 kJ ME/kg BW0.6/day to allow them to adapt from the fed to the fasted state. On the last day of each period (day 16), the pigs were fasted and fasting HP was measured. The digestible energy value was 16.0, 17.1 and 15.3 MJ/kg DM, the metabolizable energy value was 14.6, 15.5 and 13.7 MJ/kg DM and the NE value was 10.7, 11.0 and 9.4 MJ/kg DM, for the high-oil, medium-oil and low-oil corn DDGS, respectively. The NE obtained with indirect calorimetry in the present study did not differ from values calculated using previously published prediction equations. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate effects of coated compound proteases (CC protease) on apparent total tract digestibility (ATTD) of nitrogen (N) and energy, and apparent ileal digestibility (AID) of amino acids (AA) and nutrients in diets for pigs. In Exp. 1, 12 crossbred barrows (initial body weight: 20.14±1.71 kg) were housed in individual metabolism crates and allotted into 2 treatments with 6 piglets per treatment according to weight in a randomized complete block design. The 2 diets were corn-soybean meal basal diets with (0.2 g/kg) or without CC protease supplementation. The CC protease supplementation increased (p<0.05) the digestible and metabolizable N and energy values and the digestibility and retention rate of N in the diet. The ATTD of energy and nutrients had been improved (p<0.05) in the diet supplemented with CC protease. In Exp. 2, 12 crossbred barrows (initial body weight: 20.79±1.94 kg), fitted with T-cannulas at the distal ileum, were blocked by body weight into 2 groups with 6 pigs each. The diets were the same as those in Exp. 1. The CC protease increased (p<0.05) the AID of crude protein and some essential AA including arginine, isoleucine and leucine. The AID and ATTD of energy and nutrients had been improved (p<0.05) by supplemental CC protease, but the hindgut digestibility of nutrients was unaffected. Overall, the CC protease improved the ATTD of N and energy and AID of some indispensible AA and nutrients in the corn-soybean meal diet for pigs. Therefore, the CC protease supplement could improve the utilization of protein in the corn-soybean meal diet and thus contribute to lower N excretion to the environment. [ABSTRACT FROM AUTHOR]

This study was conducted to determine and compare the DE and ME content as well as the apparent total tract digestibility (ATTD) of GE in 28 samples of sorghum grain fed to growing pigs and to generate prediction equations for DE, ME, and the ATTD of GE based on chemical analysis. The 28 samples included 8 low-tannin sorghum cultivars (LTS; tannin ≤ 0.16%), 10 medium-tannin sorghum cultivars (MTS: 0.67% ≤ tannin ≤ 0.98%), and 10 high-tannin sorghum cultivars (HTS; 1.11% ≤ tannin ≤ 1.51%) obtained from 9 provinces in China and 3 samples of LTS cultivars were obtained internationally. The 28 diets were formulated to contain 96.9% of 1 of the 28 sorghum grains and 3.1% of vitamins and minerals. Eighty-four barrows (36.5 ± 3.4 kg initial BW) were used in a randomized complete block design conducted during 2 consecutive periods (n = 6 per treatment) with the pigs fed different diets during the 2 periods. For each period, pigs were placed in metabolic crates for a 5-d total collection of feces and urine following 7 d of adaptation to the diets. Among the 28 samples, GE, CP, and ADF content (DM basis) ranged from 4,363 to 4,496 kcal/kg, 8.26 to 13.41%, and 3.26 to 5.78%, respectively. The average tannin content was 0.08, 0.84, and 1.29% in the LTS, MTS, and HTS samples, respectively. The DE and ME content (DM basis) ranged from 3,861 to 3,989 and from 3,784 to 3,905 kcal/kg, respectively, in LTS; from 3,646 to 3,740 and from 3,588 to 3,669 kcal/kg, respectively, in MTS; and from 3,481 to 3,617 and from 3,418 to 3,538 kcal/kg, respectively, in HTS. The mean DE, ME, DE/ GE, ME/GE, and ATTD of GE in MTS were less than those in LTS (P < 0.05) and greater than those in HTS (P < 0.05). The correlation coefficients between DE, ME, or the ATTD of GE and tannin content were all -0.96 (P < 0.01). The best-fit equations for DE and ME (kcal/kg DM) for the complete set of 28 sorghum grains were 6,974 - (236 × % tannin) - (43.27 × % ADF) + (24.96 × % CP) - (0.71 × % GE) for DE and 3,973 - (262 × % tannin) - (27.24 × % ADF) for ME. Our results strongly indicate that the DE and ME content of sorghum grains are related to their chemical composition, especially their tannin content. The DE and ME content could decrease by more than 200 kcal/kg when the tannin content is increased by 1% in the sorghum grain. Overall, tannin is a key predictor for the DE and ME content as well as the ATTD of GE in sorghum grains, and the potent antinutritive properties from tannin should not be ignored when sorghum is used as an energy source for pigs. [ABSTRACT FROM AUTHOR]

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

This study was conducted to determine the DE and ME content of 25 samples of corn distillers dried grains with solubles (DDGS) fed to growing pigs and to generate prediction equations for DE and ME based on chemical analysis. The 25 samples included 15 full-oil (no oil extracted; ether extract [EE] > 8%) DDGS and 10 reduced-oil (oil extracted; EE < 8%) DDGS collected from 17 ethanol plants in China. A corn-soybean meal diet constituted the basal diet and the other 25 diets replaced a portion of the corn, soybean meal, and lysine of the basal diet with 28.8% of 1 of the 25 corn DDGS sources. Seventy-eight barrows (initial BW = 42.6 ± 6.2 kg) were used in the experiment conducted over 2 consecutive periods (n = 6 per treatment) using a completely randomized design. For each period, pigs were placed in metabolism cages for a 5-d total collection of feces and urine following a 7-d adaptation to the diets. Among the 25 corn DDGS samples, EE, NDF, DE, and ME content (DM basis) ranged from 2.8 to 14.2%, 31.0 to 46.6%, 3,255 to 4,103 kcal/kg, and 2,955 to 3,899 kcal/kg, respectively. Using a stepwise regression analysis, a series of DE and ME prediction equations were developed not only among all 25 DDGS but also only within 15 full-oil DDGS and 10 reduced-oil DDGS samples. The best fit equations of DE (kcal/kg DM) for the complete set of 25 DDGS, 15 full-oil DDGS, and 10 reduced-oil DDGS were 2,064 - (38.51 × % NDF) + (0.64 × % GE) - (39.70 × % ash), -(87.53 × % ADF) + (1.02 × % GE) - (22.99 × % hemicellulose), and 3,491 - (40.25 × % NDF) + (46.95 × % CP), respectively. The best fit equations for ME (kcal/kg DM) for the complete set of 25 DDGS, 15 full-oil DDGS, and 10 reduced-oil DDGS were 1,554 - (44.11 × % NDF) + (0.77 × % GE) - (68.51 × % ash), 7,898 - (42.08 × % NDF) - (136.17 × % ash) + (101.19 × % EE) (103.83 × % CP), and 4,066 - (46.30 × % NDF) + (45.80 × % CP) - (106.19 × % ash), respectively. Using the sum of squared residuals to compare the accuracy of the 3 groups of prediction equations revealed that separate equations for full-oil DDGS and reduced-oil DDGS each provided a better fit than a single equation for the entire set of DDGS sources. These results indicated that the DE and ME values in corn DDGS are related to the chemical composition, primarily the EE and fiber concentrations. Specific prediction equations derived from full-oil and reduced-oil DDGS are better than equations derived from the entire set of DDGS. [ABSTRACT FROM AUTHOR]

This experiment was conducted to evaluate the chemical composition and amino acid (AA) digestibility of sunflower seed meal (SFSM) and to use this data to develop prediction equations for estimating AA digestibility for growing pigs. Ten SFSM were collected from five provinces in China. Twelve barrows (38.8±4.6 kg), fitted with ileal T-cannula were allotted into two 6×6 Latin square designs. Each of six experimental periods comprised a 5-d adaption period followed by a 2-d collection of ileal digesta. The ten test diets contained 50% SFSM as the sole source of AA. Another nitrogen-free diet was used to measure the basal endogenous losses of crude protein (CP) and AA. Chromic oxide (0.3%) was used as an inert marker in each diet. There was considerable variation (CV>10%) among the ten SFSM in chemical composition (dry matter [DM]). The concentration of CP and ether extract (EE) ranged from 29.33% to 39.09% and 0.88% to 11.33%, respectively. Crude fibre (CF), neutral detergent fibre and acid detergent fibre ranged from 21.46% to 36.42%, 38.15% to 55.40%, and 24.59% to 37.34%, respectively. There was variation among the ten SFSM in apparent ileal digestibility (AID) and standardized ileal digestibility (SID) for lysine and threonine, which ranged from 63.16 to 79.21 and 55.19% to 72.04% for AID and 67.03% to 82.07% and 61.97% to 77.01% for SID, respectively. The variation in CP and methionine ranged from 60.13% to 74.72% and 74.79% to 88.60% for AID and 66.70% to 79.31% and 77.16% to 90.27% for SID, respectively. Methionine was a good indicator to predict AA digestibility. These results indicate that conventional chemical composition of SFSM was variable (CV>10%) among the ten SFSM (DM). The results of AID, SID and prediction equations could be used to evaluate the digestibility of SFSM in growing pigs. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine the digestible energy (DE) and metabolizable energy (ME) contents of corn gluten feed (CGF) for finishing pigs and to develop equations predicting the DE and ME content from the chemical composition of the CGF samples, as well as validate the accuracy of the prediction equations. In Exp. 1, ten CGF samples from seven provinces of China were collected and fed to 66 finishing barrows (Duroc×Landrace×Yorkshire) with an initial body weight (BW) of 51.9±5.5 kg. The pigs were assigned to 11 diets comprising one basal diet and 10 CGF test diets with six pigs fed each diet. The basal diet contained corn (76%), dehulled soybean meal (21%) and premix (3%). The ten test diets were formulated by substituting 25% of the corn and dehulled soybean meal with CGF and contained corn (57%), dehulled soybean meal (15.75%), CGF (24.25%) and premix (3%). In Exp. 2, two additional CGF sources were collected as validation samples to test the accuracy of the prediction equations. In this experiment, 18 barrows (Duroc×Landrace×Yorkshire) with an initial BW of 61.1±4.0 kg were randomly allotted to be fed either the basal diet or two CGF containing diets which had a similar composition as used in Exp. 1. The DE and ME of CGF ranged from 10.37 to 12.85 MJ/kg of dry matter (DM) and 9.53 to 12.49 MJ/kg of DM, respectively. Through stepwise regression analysis, several prediction equations of DE and ME were generated. The best fit equations were: DE, MJ/kg of DM = 18.30-0.13 neutral detergent fiber-0.22 ether extract, with R² = 0.95, residual standard deviation (RSD) = 0.21 and p<0.01; and ME, MJ/kg of DM = 12.82+0.11 Starch-0.26 acid detergent fiber, with R² = 0.94, RSD = 0.20 and p<0.01. These results indicate that the DE and ME content of CGF varied substantially but the DE and ME for finishing pigs can be accurately predicted from equations based on nutritional analysis. [ABSTRACT FROM AUTHOR]

A new strategy of co-inoculating Bacillus subtilis MA139 with Streptococcus thermophilus and Saccharomyces cerevisiae was used to produce fermented soybean meal (FSBM). Three experiments were conducted to determine the concentration of digestible energy (DE) and metabolizable energy (ME) (Exp. 1), apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AA) (Exp. 2), and feeding value (Exp. 3) of FSBM produced by this new strategy (NFSB) compared with soybean meal (SBM) and conventionally available FSBM (Suprotein). In Exp. 1, twenty-four barrows (initial body weight [BW] of 32.2 ±1.7 kg) were randomly allotted to 1 of 4 diets with 6 replicates per diet. A corn basal diet and 3 diets based on a mixture of corn and 1 of 3 soybean products listed above were formulated and the DE and ME contents were determined by the difference method. The results showed that there were no differences in DE and ME between SBM and either FSBM product (p>0.05). In Exp. 2, eight barrows (initial BW of 26.8±1.5 kg) were fitted with ileal T-cannulaes and used in a replicated 4×4 Latin square design. Three corn-starch-based diets were formulated using each of the 3 soybean products as the sole source of AA. A nitrogen-free diet was also formulated to measure endogenous losses of AA. The results showed that the SID of all AA except arginine and histidine was similar for NFSB and SBM (p>0.05), but Suprotein had greater (p<0.05) SID of most AA except lysine, aspartate, glycine and proline than NFSB. In Exp. 3, a total of 144 piglets (initial BW of 8.8±1.2 kg) were blocked by weight and fed 1 of 4 diets including a control diet with 24% SBM as well as diets containing 6% and 12% NFSB or 12% Suprotein added at the expense of SBM. During d 15 to 28, replacing SBM with 6% NFSB significantly improved average daily gain (ADG) and average daily feed intake (ADFI) (p<0.05) for nursery piglets. During the overall experiment, ADG of piglets fed diets containing 6% NFSB was significantly greater (p<0.05) than that of piglets fed SBM. In conclusion, fermentation with the new strategy did not affect the energy content or the AID and the SID of AA in SBM. However, inclusion of 6% NFSB in diets fed to nursery piglets improved performance after weaning likely as a result of better nutritional status and reduced immunological challenge. [ABSTRACT FROM AUTHOR]

ABSTRACT: A total of 216 weaning pigs were used in 2 experiments to determine the effects of dietary supplementation of yeast culture (YC) at different dose levels on the growth performance, nutrient digestibility, intestinal morphology, intestinal microflora, and immune response in weanling pigs and to determine whether YC can be a candidate to replace antibiotic growth promoters (AGP). In Exp. 1, 192 pigs (7.5 + 0.2 kg of BW) weaned at 28 d of age were randomly allotted to 6 treatments: 1) control (without AGP or YC); 2) AGP (chiortetracycline, 80 mg/kg); 3) 2.5 g/ kg of YC (Diamond V XP Yeast Culture); 4) 5 g/kg of YC; 5)10 g/kg of YC; and 6) 20 g/kg of YC. Each treatment had 8 replicated pens with 4 pigs per pen. Pigs were fed the experimental diets for 21 d. Average daily gain of pigs fed 5 g/kg of YC was greater (P < 0.05) than that of pigs in the control and other YC groups. However, there was no difference between the YC and AGP group. Pigs supplemented with 5 g/kg of YC, 10 g/kg of YC, and AGP had a greater (P < 0.01) ADFI than the control; however, G:F was not affected by treatment. Thus, 5 g/kg of YC supplementation level was chosen for Exp. 2. In Exp. 2, to elucidate the mode of action of YC, 24 nursery pigs (5.8 + 0.1 kg of BW; 21 d of age) were randomly allotted into 3 treatments for a 21-d trial. Treatments consisted of 1) control (without AGP or YC), 2) AGP, and 3) 5 g/kg of YC. Blood samples were collected weekly to measure CD4+, CD8+ percentage, and blood cytokine content. All pigs were harvested to determine treatment effects on gut microbiota, morphology, and immune function. Dietary supplementation of 5 g/kg of YC improved (P < 0.05) ADG of pigs compared with the control group, but performance of pigs fed YC was similar to those fed AGP. Pigs receiving 5 g/kg of YC had greater (P < 0.05) digestibility of DM, CP, GE, and jejunal villus height and villus height:crypt depth ratio (P < 0.05) compared with pigs fed the control diet. However, rio differences in performance, digestibility, or gut morphology were observed between pigs fed YC and AGP. Gut interferon (IFN)-γ concentrations were greater (P < 0.01) for pigs supplemented with YC compared with control pigs and pigs supplemented with AGP on d 21. However, plasma IFN-γ concentrations were decreased (P < 0.01) in pigs supplemented with YC and AGP compared with control pigs on d 7, and CD4+ was decreased (P < 0.01) in pigs supplemented with YC and AGP on d 14. Results indicate that dietary YC supplementation at 5 g/kg had a positive effect on growth performance of nursery pigs by improving jejunal villus height and villus height:crypt depth ratio and by modulating gut immune response. The comparable effect of 5 g/kg of YC supplementation and AGP on the growth performance of nursery pigs indicates that YC may be a good candidate as an antibiotic alternative. [ABSTRACT FROM AUTHOR]

The effects of lysine restriction during grower phase and realimentation during finisher phase on growth performance, nutrient digestibility, blood metabolites, carcass traits and pork quality were studied. Sixty-four pigs (two castrated males and two females per pen) weighing 34.34±5.22 kg were assigned to four dietary treatments. During grower (35-55 kg), pigs were fed isoenergetic lysine-restricted diets. The different lysine content of diets were 0.950 (NRC recommendation), 0.760, 0.665 and 0.570%, corresponding to lysine restriction of 20, 30 and 40%. Then all pigs were fed with common finisher 1 (55-85 kg) and 2 (85-115 kg) diets. Lysine restriction during the grower phase resulted in poor performance and lower concentration of blood metabolites but improved the nutrient digestibility and efficiency of lysine utilization. Compensatory growth response in terms of improved weight gain and feed efficiency was observed in pigs previously fed lysine-restricted diets during finisher 1, but the concentration of blood urea nitrogen and total protein were lower. No differences in growth performance, digestibility of nutrients and blood metabolites were noted during finisher 2. Lysine restriction of grower diets decreased the dressing percentage (quadratic, P=0.024), and protein content of longissimus muscle (linear P=0.034, and quadratic P=0.009). Thus, it could be concluded that pigs subjected to lysine restriction during grower phase exhibited compensatory growth responses in weight gain and improved efficiency of feed and lysine utilization for weight gain and lean accretion during finisher phase. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the total endogenous Ca output and to determine the effects of dietary Ca concentrations on endogenous Ca outputs, the true total tract digestibility (TTTD), and balance of Ca, P, and N in growing pigs. Thirty-six growing barrows (initial BW: 42.2 ± 2.0 kg) were placed in metabolism crates and allotted to a randomized complete block design with 6 diets and 6 pigs per diet. Diets were based on cornstarch and casein, and were formulated to provide the following levels of total Ca: 0.13,0.31,0.50,0.68, 0.87, and 1.05%, and the analyzed ratio of total Ca to total P was between 1.16:1 and 1.23:1. Calcitic limestone and mono-sodium phosphate provided the majority of the Ca and P in the diets. Feces and urine samples were collected from d 8 to d 12. Total endogenous Ca and P outputs and values for TTTD of Ca and P were determined using the regression procedure. Results indicate that the estimated total endogenous Ca and P outputs were 0.508 and 0.428 g/kg DMI, respectively. The TTTD of Ca in calcitic limestone was estimated at 76.8% and the TTTD of P in monosodium phosphate was estimated at 88.8%. It is concluded that the dietary concentration of Ca affects the retention of P significantly (P < 0.01), but does not affect the retention of Ca or N. [ABSTRACT FROM AUTHOR]

This study assessed the effects of proteinate complex zinc (Zn) on oxidative stress, trace elements concentrations and immune functions in weaned piglets. Three hundred newly weaned barrows (Duroc x Landrace x Yorkshire), 28 d of age, were randomly allotted to 3 dietary groups of 5 replicate pens per group for 4 wk of feeding. Experimental diets were: (1) zinc deficient diet (ZnD, 24 mg/kg Zn supplementation fromZnSO4), (2) inorganic Zndiet supplemented by 120 mg/ kg of Zn from Zn sulfate (ZnSO4), and (3) organic Zn diet supplemented by 120 mg/kg of Zn from proteinate complex Zn (PC-Zn). The Zn, Cu, Fe and Mn concentrations in the spleen and liver were measured using inductively coupled plasma-mass spectrometry (ICP-MS) technology. The activities of serous alkaline phosphatase (ALP), alanine transaminase (ALT) and aspartate transaminase (AST) were measured with a biochemical autoanalyzer. The concentration of malondialdehyde (MDA) was determined according to the thiobarbituric acid reactive substances (TBARS) assay and the activity of Mn and Cu/Zn superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the spleen and liver were analyzed according to the xanthine oxidase and ammonium molybdate chromogenic methods, respectively. The hepatic MT content was examined by the Cd/hemoglobin affinity assay The levels of splenic interleukin (IL)-2, IL-4, IL-10 and interferon (IFN)-γ were determined by IL-2, IL-4, IL-10 and IFN-γ enzyme linked immunosorbent assay (ELISA) kits, respectively. The proportions of CD3+, CD4+ and CD8+ T lymphocyte were analyzed with ELISA methods. The results showed that the accumulation of Zn in the spleen, levels of SOD, GSH-Px, IL-4, IL-10, the proportions of CD3+ and CD4+ T lymphocyte, and the ratio of CD47CD8+ T lymphocyte were increased by organic Zn supplementation, while the levels of MDA, IFN-γ and proportion of CD8+T lymphocyte were lowered. These findings indicate that Zn can improve the antioxidant potential and immune functions related to T lymphocyte production in the spleen of weaned piglets. [ABSTRACT FROM AUTHOR]