Importance of dietary supplementation of soluble and insoluble fibers to sows subjected to high ambient temperatures during late gestation and effects on lactation performance.

Heat stress adversely affects sows' performance, which can be improved by applying proper nutritional strategies. This study was conducted to investigate the interactive effects of dietary fiber levels and sources on sows' reproductive performance, metabolic response during gestation, and the carry-over influence on litter performance in the lactation period during heat stress (average room temperature of 27.1 °C). Fifty-four multiparous sows (Landrace × Yorkshire; initial body weight of 236.3 ± 16 kg; 2, 3 and 4 parities) at d 90 of gestation were assigned to a 2 × 3 factorial arrangement (9 sows/treatment), involving 2 dietary fiber levels (4.5% and 6% crude fiber) and 3 dietary fiber sources (wheat bran [WB], palm kernel meal [PK], and beet pulp [BP]). Sows fed the BP diet had highest (P < 0.01) feed intake and constipation index and lowest (P < 0.01) farrowing duration. Piglet weight (P = 0.041) and litter weight (P < 0.01) at weaning were higher in sows in the BP treatment compared to PK treatment. Sows in the BP treatment showed the greatest (P < 0.01) digestibility of crude protein and neutral detergent fiber. The fecal concentration of acetate was the lowest (P < 0.01) in the PK treatment. Total short-chain fatty acid production was increased in the WB and BP treatments compared with the PK. Sows in the BP treatment showed the lowest (P = 0.036) hair cortisol. The blood insulin concentration of sows was higher (P = 0.026) in the high fiber (6%) treatment compared with the low fiber (4.5%) treatment at 90 min and 120 min after the meal. The concentration of phthalic acid, succinic acid, phenylethylamine, hydrocinnamic acid, iron, linoleic acid, glycerol, ketone, and formamide were increased (P < 0.05) in the BP treatment compared with the WB. The BP treatment with high soluble fiber content improved the constipation index, farrowing duration, and litter performance, while high insoluble fibers increased sows comfort and reduced stress factors including respiratory rate and rectal temperature. Therefore, both soluble and insoluble sources of fiber are necessary to be added to the diet of gestating sows.

Improvement of weanling pigs immune status and metabolic condition using ultraweak light.

Weaning stress is the most common issue in swine farms, which increases mortality and morbidity. The use of artificial light is an option for modifying the immune system and metabolic pathways. This study aimed to evaluate the influence of ultraweak light (Photonia) on growth performance, immune system and metabolism of weanling pigs, and the carry-over effect on the growth performance in postweanling growing stages. A total of 30 weaned pigs with an average initial body weight of 7.06 ± 0.11 kg (age: 21 days) were allotted two treatments (Control and Photonia) with 15 replicates. The pelleted form diets were prepared for pigs in three phases including phase 1 (Days 0-14), phase 2 (Days 15-28) and phase 3 (Days 29-48). The gain-to-feed ratio (G:F) of pigs was significantly greater in the Photonia treatment. On Day 28, a higher concentration of immunoglobin A (IgA) (p < 0.01) and IgG (p < 0.01) was observed in the Photonia pigs. On Day 48, the Photonia treatment showed a greater serum IgA (p < 0.01) and IgG (p < 0.05). The concentration of interleukin (IL)-6 was decreased (p < 0.05) in the Photonia treatment. At Day 48, the concentrations of tumour necrotic factor-α, IL-1ß and IL-6 in serum were decreased (p < 0.05) in pigs in the Photonia treatment. Metabolic pathways analysis showed that the Photonia treatment increased the d-glutamine, d-glutamate, alanine, aspartate, glutamate and phenylalanine compared with the control treatment. In conclusion, the use of Photonia for weanling pigs is recommended due to improved G:F, immune status and activation of amino acids metabolic pathways including d-glutamine, d-glutamate, alanine, aspartate, glutamate and phenylalanine.

Exogenous protease influences protein digestibility, growth performance, and gut microflora in weanling pigs on a limited protein diet.

The study was conducted to evaluate the impact of dietary level of crude protein (CP) and protease supplementation on growth performance, digestibility of nutrients, intestinal morphology, and gut microbiota in weaning pigs. Three hundred cross-bred piglets (Duroc × Landrace × Yorkshire) were allotted to five dietary treatments on the basis of initial body weight (BW) and sex. Pigs were group-housed in pens with each treatment with 10 replicate pens with six pigs per pen. The treatments included a standard diet (STD), STD with 0.6% lower protein (STD0.6), STD with 0.6% lower protein and protease supplementation (Pro0.6), STD with 1.0% lower protein (STD1.0), STD with 1.0% lower protein and protease supplementation (Pro1.0). Results indicated a higher BW (p < 0.05) of piglets in the Pro0.6 group at days 0-42 compared to the STD0.6 and STD1.0 groups. The average daily gain was higher (p < 0.05) in the Pro0.6 treatments at days 0-42 compared to the STD0.6 and STD1.0. The gain to feed ratio was higher (p < 0.05) in the STD, and Pro0.6 groups compared to the STD0.6, Pro1.0 and the STD1.0 groups at days 0-42. Dry matter digestibility was lower (p < 0.05) in the STD1.0 group than the Pro0.6 and Pro1.0 groups. The crude protein digestibility was higher (p < 0.05) in the Pro0.6 group compared to the STD, STD0.6 and STD1.0 treatment groups while crude fat digestibility was higher (p < 0.05) in the STD and Pro0.6 compared with the STD0.6 and STD1.0 groups. Digestibility was higher for histidine (p < 0.05), leucine (p < 0.05) in the protease Pro0.6 and Pro1.0 groups than in the STD0.6 and STD1.0 groups. The digestibility of non-essential AA was higher for alanine (p < 0.05) in the Pro0.6 than the STD1.0 group. For faecal microbial population, Faecalibacterium abundance was higher (p < 0.05) in the Pro0.6 compared to all the other groups while the population of Actinobacteria was greater (p < 0.05) in the STD group and lowest in the Pro1.0 treatment. In the ileum, villus height was greater (p < 0.05) in the protease Pro0.6, and Pro1.0 groups compared to the STD0.6, and STD1.0 groups while the villus height to crypts depth ratio was lower (p < 0.05) in the STD 1.0 group compared to the STD, Pro0.6, and Pro1.0 groups. Based on these results, dietary protease supplementation improved nutrient digestibility and gut histo-morphology translating to improved utilisation of nutrients thus positively impacting growth performance in weaned pigs. Further, reducing the CP content in the diets increased the abundance of Muribaculaceae while protease supplementation increased the population of Faecalibacterium in the gut of the weanling piglets on the STD0.6 diet.

Influence of dietary fiber intake and soluble to insoluble fiber ratio on reproductive performance of sows during late gestation under hot climatic conditions.

This study evaluated dietary fiber (DF) level and the ratio of soluble fiber (SF): insoluble fiber (ISF) impact on sows' reproductive performance under heat stress. Forty sows at day 90 of gestation were assigned to four treatments. HH diet had, 20% DF, 1:4, SF:ISF ratio; HL, 20% DF, 1:6, SF:ISF ratio; LH, 14% DF, 1:4, SF:ISF, LL, 14% DF, 1:6, SF:ISF. Results showed that; lactation back-fat loss was lower (P < 0.05) in HH . Feed intake was higher (P < 0.05) in HH and HL. Farrowing duration shorter (P < 0.05) in HH. Constipation index was higher (P < 0.05) in HH and LH. Weaning piglets' body weight was greater (P < 0.05) in HH than LH and LL. Hair cortisol was lower (P < 0.05) in HH than HL, and LL. Acetate, propionate, isovalerate, and butyrate was higher (P < 0.05) in HH and LH. Plasma zonulin, fecal lipocalin-2 were lower (P < 0.05) in HH, and HL. Superoxide dismutase tended to be higher (P = 0.056) and malondialdehyde tended to be lower (P = 0.069) in HH and HL. We opined that higher levels of dietary fiber and soluble fiber could ameliorate heat stress in gestating sows.

Effects of dietary arginine in ameliorating the deleterious effects induced by mycotoxins on growth, immune system, body organs in growing pigs.

Mycotoxin contamination in pig feeds has a negative impact on growth performance, the immune system, and major body organs. Arginine (Arg) plays an important role in animals' body biochemistry and physiology. This study aimed to determine the effect of dietary Arg supplementation on mitigating the negative effects of mycotoxins in growing pigs. A total of 72 growing pigs (Landrace × Large white) with initial mean body weight (BW) = 55 ± 2.5 kg were allotted to four treatment groups with three replicates per group of six pigs per replicate in a completely randomized design. The treatments included a non-toxin diet with 1.2% Arg (NT1.2) and mycotoxin-challenged treatments supplemented with 1.2% Arg (TX1.2), 1.3% Arg (TX1.3), and 1.4% Arg (TX1.4). Statistical analysis of data included the effects of dietary level of Arg. The results indicated a significantly higher BW (p < 0.05), average daily gain (p < 0.05), and gain-to-feed ratio (p < 0.05) in the NT1.2 group than in the TX1.2, TX1.3, and TX1.4 groups. The relative weight of the liver was higher (p < 0.05) in the TX1.2 compared to that of the NT1.2 group, although it was not different from that of TX1.3 and TX1.4. The level of tumor necrosis factor-alpha was significantly up-regulated (p < 0.05) in the liver tissue of the TX1.2 group compared to that of the other treatments. Overall, dietary Arg supplementation remedied liver injury and alleviated the compromised immune system caused by mycotoxin toxicity.

Effects of various cooling methods and drinking water temperatures on reproductive performance and behavior in heat stressed sows.

The purpose of this study is to evaluate the effects of multiple cooling systems and different drinking water temperatures (DWT) on the performance of sows and their hair cortisol levels during heat stress. In this study, the effect of four different cooling systems: air conditioner (AC), cooling pad (CP), snout cooling (SC), and mist spray (MS), and two DWT, namely low water temperature (LWT) and high water temperature (HWT) on 48 multiparous sows (Landrace × Yorkshire; 242.84 ± 2.89 kg) was tested. The experiment is based on the use of eight replicas during a 21-days test. Different behaviors were recorded under different cooling treatments in sows. As a result, behaviors such as drinking, standing, and position change were found to be lower in sows under the AC and CP treatments than in those under the SC and MS treatments. Lying behavior increased under the AC and CP systems as compared with that under the SC and MS, systems. The average daily feed intake (ADFI) in sows and weight at weaning in piglets was higher under the AC, CP, and LWT treatments than under the SC, MS and HWT treatments. Sows subjected to SC and MS treatment showed higher hair cortisol levels, rectal temperature, and respiratory rate during lactation than those under AC and CP treatments. Hair cortisol levels, rectal temperature, and respiratory rate were also higher under the HWT than under the LWT treatment. As per the results of this study, the LWT has no significant effect on any of the behavioral factors. Taken together, the use of AC and CP cooling treatment is highly recommended to improve the behavior and to reduce the stress levels in lactating sows.

Metabolic Responses of Dietary Fiber during Heat Stress: Effects on Reproductive Performance and Stress Level of Gestating Sows.

Heat stress is an important issue, and the addition of fiber to the diet is an option in modifying intestinal health. This study evaluated the effect of acid detergent fiber (ADF) levels on reproductive performance, intestinal integrity, and metabolism of gestating sows, and its carry-over effect on the lactation period during heat stress. The diets included 4.3% (Low fiber; LF), 5.4% (Medium fiber; MF), and 6.5% (High fiber; HF) ADF. Sows fed the HF diet showed a lower respiratory rate, hair cortisol concentration, and farrowing duration compared with the LF treatment. The HF diet increased the pyruvate, citrate cycle, glyoxylate, dicarboxylate, and thiamine metabolism compared with the MF. The concentration of acetate and total short-chain fatty acids were increased in the sows fed the HF diet. The gene expression of glucose transporter 3 and glucose transporter 4 was increased in the HF treatment. The gene expression of heat shock protein 70 was decreased in the HF treatment. The HF diet during gestation increased feed intake, constipation index, piglet weight, and litter weight compared with the LF. Sows in the LF treatment showed the greatest digestibility of crude protein and the lowest digestibility of ADF. In conclusion, a 6.5% ADF level is recommended for gestating sows during heat stress.

Supplementation of nano-zinc in lower doses as an alternative to pharmacological doses of ZnO in weanling pigs.

A set of studies was performed to determine the influence of dietary ZnO concentration and source during two phases (days 0 to 14 and days 15 to 28). Experiment 1: 168 weaned piglets were allocated to four treatment groups in six replicates. The treatments included a basal diet without ZnO supplementation (control), 2,500 mg ZnO/kg (In2500), 500 mg nano-ZnO/kg (N500), and 150 mg nano-ZnO/kg (N150). Experiment 2: 168 weaned piglets were divided into three treatment groups with eight replicates. The treatments included control, In2500, N300, and 150 mg nano-ZnO/kg (N150). An in vitro trial showed that the growth of Listeria monocytogenes, Escherichia coli, and Salmonella typhimurium was inhibited when exposed to 300 and 500 ppm of ZnO after 24 h of incubation. In experiment 1, the average daily gain (ADG) by the pigs was improved in the N500 and IN2500 treatment groups. Colonization of coliforms and Clostridium spp. significantly decreased in the pigs fed the N500 and IN2500 diets in phase 1. The total plasma antioxidant capacity was greater in the IN2500 and N500 treatment groups than in the control. Superoxide dismutase (SOD) activity was greater in pigs fed the IN2500 (phase 1) or the IN2500 and N500 (phase 2) diets than in the control and N150 treatment group. In experiment 2, pigs in the N300 treatment group showed a higher ADG and lower fecal score colonization of coliforms and Clostridium spp. compared with those in the N150 treatment group. In conclusion, nano-ZnO at a dose of 300 ppm showed the same growth as the pharmacological dose of Zn. This provides an option to the pharmacological dose.

Prediction of calcium and phosphorus requirements for pigs in different bodyweight ranges using a meta-analysis.

Several studies have focused on Ca and P requirements for pigs. These requirements are estimated from their retention and bone formation. However, modern pig breeds have different responses to dietary Ca and P than traditional breeds, and their requirements are expected to change on an annual basis. Besides individual Ca and P needs, the Ca to P ratio (Ca/P) is an important factor in determining requirements. This study aimed to implement a linear and quadratic regression analysis to estimate Ca and P requirements based on average daily gain (ADG), apparent total tract digestibility (ATTD) of Ca (ATTD-Ca), ATTD of P (ATTD-P), and crude protein (CP) digestibility. Results show that Ca/P had linear and quadratic effects on ADG in the phytase-supplemented (PS) group in both the 6-11 kg and 11-25 kg categories. In the latter category, the CP digestibility was linearly increased in response to increasing Ca/P in the without-phytase (WP) group. In the 25-50 kg category, there was a linear response of ADG and linear and quadratic responses of CP digestibility to Ca/P in the PS group, while a linear and quadratic increase in CP digestibility and a quadratic effect on ATTD-Ca were observed in the WP group. In the 50-75 kg category, Ca/P had significant quadratic effects on ADG in the PS and WP groups, along with significant linear and quadratic effects on ATTD-Ca. In addition, Ca/P had significant quadratic effects on ATTD-P and led to a significant linear and quadratic increase in the CP digestibility in the WP group. In the 75-100 kg category, analysis showed a significant decrease in ATTD-Ca and ATTD-P in the PS and WP groups; in the latter, ATTD-P and ATTD-Ca were linearly decreased by increasing Ca/P. In conclusion, our equations predicted a higher Ca/P in the 6-25 kg bodyweight categories and a lower Ca/P in the 50-100 kg category than that recommended in the literature.

Effects of Scopoletin Supplementation and Stocking Density on Growth Performance, Antioxidant Activity, and Meat Quality of Korean Native Broiler Chickens.

Stocking density stress is one of the most common management stressors in the poultry industry. The present study was designed to investigate the effect of dietary Sophora koreensis (SK; 0 and 20 mg/kg diet) and stocking density (SD; 14 and 16 chickens/m2) on the antioxidant status, meat quality, and growth performance of native Korean chickens. There was a lower concentration of malondialdehyde (MDA) and a higher concentration of catalase, superoxide dismutase (SOD), and total antioxidant capacity in the serum and leg muscle with the supplementation of SK. The concentration of MDA was increased and concentrations of SOD were decreased in the leg muscle of chickens in low SD treatments. The SK-supplemented treatments showed an increased 3-ethylbenzothiazoline-6-sulfonate-reducing activity of leg muscles. The higher water holding capacity of breast muscle and a lower cooking loss and pH were shown in the SK-supplemented treatments. The addition of dietary SK resulted in a greater body weight gain and greater spleen and bursa Fabricius weight, as well as lower feed intake and abdominal fat. The low SD and supplementation of SK increased the concentrations of cholesterol. The concentration of glucose was increased in the low SD treatment. Corticosterone level was decreased in the SK-supplemented and low SD treatments. In conclusion, SK supplementation reduced the oxidative stress and increased meat quality and antioxidant status of chickens apart from the SD stress.

Supplementation of enzyme cocktail in chickens diet is an effective approach to increase the utilization of nutrient in wheat-based diets.

This experiment was conducted to evaluate the effect of supplementing enzyme cocktail on growth performance, digestibility of nutrients, and monosaccharide concentration in ileum and ceca of broiler chickens fed wheat-based diets. A total of 600 male broilers (42.26 ± 1.76 g, 0 day old) were used for 35 days of feeding trial consisting of 2 phases (starter phase from d 0 to 21 and finisher phase from d 21 to 35). Four dietary treatments were prepared based on wheat diets containing four levels of enzyme cocktail supplementation at 0, 0.2, 0.3, and 20 g/kg. Overall, dietary enzyme cocktail supplementation decreased feed conversion ratio (linear p = 0.007; quadratic p = 0.013) and improved (linear p < 0.05) the apparent ileal digestibility of dry matter (DM), crude protein, and soluble and insoluble non-starch polysaccharides. The apparent total tract digestibility of DM and gross energy were increased (linear p < 0.01) with increasing supplementation levels of the dietary enzyme cocktail. The concentrations of arabinose, xylose, mannose, and glucose in ileal digesta were linearly increased (p < 0.01) with increasing enzyme cocktail supplementation levels. In addition, the quadratic effect was observed (quadratic p = 0.046) in mannose concentration of ileal digesta. The concentration of arabinose, xylose, mannose, and galactose in cecal digesta was increased (linear p < 0.05) with increasing dietary enzyme cocktail supplementation levels. The supplementation of enzyme cocktail efficiently increased the utilization of nutrients in broiler and there was no adverse effects of high dosage supplementation level.

Effects of hot-melt extruded nano-copper on the Cu bioavailability and growth of broiler chickens.

This study was aimed to investigate the Cu bioavailability, growth response, digestibility of nutrients, and blood metabolites of broiler chicks fed CuSO4 in nano or common forms. A total of 720 broiler chickens were distributed between eight treatments according to a completely randomized design. There were 8 treatments and 6 replicates in each treatment with 15 birds/replicate. The treatments were divided into common copper sulfate at the doses of 16 ppm, 40 ppm, 80 ppm, and 120 ppm (INO) and hot-melt extruded copper sulfate at the doses of 16 ppm, 40 ppm, 80 ppm, and 120 ppm (HME-Cu). The experiment was operated for 35 days in 2 phases (phase 1, d 0 to 14; and phase 2, d 15 to 35). No significant differences were shown in growth performance, feed intake, FCR, and nutrient digestibility among the treatments. The concentration of Cu in the serum was increased in the HME-Cu broilers compared with the INO broilers at phase 2. A linear increase was observed in the concentration of Cu in the liver in broilers fed INO diets, however, no significant differences were observed by the supplementation of HME-Cu levels. The linear increase was detected in the content of Cu in excreta in the INO and HME-Cu treatments by increasing the dietary Cu content. The HME-Cu treatments showed a lower Cu concentration in the excreta compared with the INO treatments. The higher bioavailability of Cu in HME form can decrease the recommended dose of Cu in broiler diets.

Effects of Lactobacillus salivarius isolated from feces of fast-growing pigs on intestinal microbiota and morphology of suckling piglets.

The study determined the effects of Lactobacillus salivarius (LS) administered early in the life of suckling piglets on their growth performance, gut morphology, and gut microbiota. Thirty litters of 3-day-old crossbreed piglets were randomly assigned to one of the three treatments, and treatments were commenced on day 3 after birth. During the whole period of the experiment, the piglets were kept with their mothers and left to suckle ad libitum while being supplemented with a milk formula with or without the bacterial probiotic supplemented. The control group (CON) was not treated with probiotics, the HLS group was treated with LS144 (HLS) screened from feces of fast-growing pigs with high body mass index (BMI) while the NLS group was supplemented with LS160 (NLS) screened from feces obtained from pigs of normal BMI. At the weaning time, a higher abundance of Actinobacteria, Lentisphaerae, and Elusimicrobia phyla were observed in NLS piglets, whereas the abundance of Fibrobacteres phylum was significantly reduced in NLS and HLS piglets compared with the CON. A greater abundance of Lactobacillus was detected in the HLS treatment compared with the CON. The abundance of Bacteroides and Fibrobacter was higher in the CON piglets compared with the HLS and NLS piglets. Compared with the CON group, the oral administration of LS significantly increased the number of Lactobacillus and villus height in the duodenum, jejunum, and ileum. Moreover, the villus height of the duodenum was significantly improved in the HLS treatment compared with the NLS treatment. Based on the findings in the neonatal piglet model, we suggest that oral supplementation of LS, particularly LS isolated from high BMI pigs, could be beneficial by improving the intestinal villus height.

Effects of free feeding time system and energy level to improve the reproductive performance of lactating sows during summer.

The reproductive performance of lactating sows was investigated by using different feeding methods including conventional feeding (CF, 3 times/d) or free feeding (FF), and different dietary energy level including low energy (LE: 3,300) or high energy (HE: 3,400 kcal/kg) during the hot season. A total of twenty-eight crossbred (Yorkshire × Landrace) sows were distributed into four treatments as a 2 × 2 factorial arrangement. Sows in the FF group showed lower body weight and backfat loss (p < 0.05) compared with the CF group. Backfat loss during lactation was lower (p < 0.05) in sows fed HE diet than in that fed LE diet. There were no significant differences in litter survival rate and weaning to estrus interval, but the litter weight at weaning was improved (p < 0.05) in FF and HE sows. Hence, it is concluded that using the free-feeding system or increased dietary energy density leads to improved sow performance during hot ambient temperature.

Night feeding in lactating sows is an essential management approach to decrease the detrimental impacts of heat stress.

The present study investigated the litter performance of multiparous sows had different feeding frequencies during summer season. A total of 60 crossbred multiparous sows was allotted to one of two treatments based on body weight (BW) according to a completely randomized design. Two different feeding frequencies based on NRC (National Research Council) were applied as conventional feeding (T1; 2 kg per meal at 06:00, 11:00, and 17:00) and night feeding (T2; 1.5 kg per meal at 06:00, 11:00, 17:00, and 2 kg at 22:00). Sows in T2 treatment had lower (p < 0.05) BW changes during lactation. The backfat thickness change of sows was decreased in T2 treatment during lactation (p < 0.05). The daily feed intake differed significantly between T1 and T2 with increased feed intake of the T2 group at 5.47 kg/d to 5.14 kg/d in the T1 group (p < 0.05). There was a significant difference in total weight of weaned piglets between T1 (70.50 kg) and T2 (74.34 kg). A greater total litter weight gain was observed in sows in T2 treatment. Night feeding is suggested for lactating sows with significant beneficial effects on litter growth during summer season.

Effects of hot melt extrusion processed nano-iron on growth performance, blood composition, and iron bioavailability in weanling pigs.

This study was conducted to investigate the effects of hot melt extrusion (HME) nano-iron as an alternative for the common ferrous sulfate on iron (Fe) bioavailability, growth performance, nutrient digestibility, intestinal morphology, and intestinal microbiota of weanling pigs. A total of 200 piglets (Landrace × Yorkshire × Duroc) were randomly allotted to seven treatments on the basis of initial body weight (BW) and sex. Treatments were the INO100 (100 ppm Fe as FeSO4), HME-Fe levels (50, 75, and 100 ppm nano-Fe as FeSO4). ORG100 (100 ppm Fe as iron methionine). In phase 1, the HME50 pigs showed the lowest Fe content in feed and feces. Plasma Fe concentration was increased in HME100 and ORG100 pigs. In phase 2, there were significantly lower concentration of Fe in feed and feces of HME50 pigs (p < 0.01). A lower Fe concentration in the plasma and liver were observed in HME50 pigs compared with HME100 pigs. Concentration of red blood cell (RBC) was the lowest (p < 0.01) for HME50 pigs. During phase 2, the HME100, HME75, and ORG100 pigs showed a higher RBC and hemoglobin values compared with HME50 pigs. Digestibility of gross energy (GE) and crude protein (CP) were significantly higher in HME100 pigs compared with HME50 pigs. There was an increased (p < 0.01) villus height in the duodenum and jejunum of HME100 pigs compared with HME50 pigs. It is concluded that dietary Fe does not improve growth performance of weanling pigs; however, increasing the dietary iron concentration in weanling piglets increased the RBC and hemoglobin. In addition, the potential ability of HME to be used at a lower level (HME75) was observed.