We conducted two studies to determine the bioavailability and apparent digestibility of P in a low-phytate corn hybrid (.28% total P, .10% phytate P) genetically modified to be homozygous for the 1pa1-1 allele and a nearly isogenic corn hybrid (normal) (.25% total P, .20% phytate P). Additionally, we conducted an in vitro assay involving a peptic and pancreatin digestion to estimate P availability. The first study used 50 individually penned pigs (initial body weight 9 kg) and 10 treatments in a randomized complete block design. A cornstarch-soybean meal basal diet (.6% Ca, .2% P) was used. Treatments consisted of the basal diet and the basal diet plus .05, .10, or .15% P from monosodium phosphate (MSP), low-phytate corn, or normal corn. After a 35-d feeding period, pigs were killed to collect the fourth metacarpal for measurements of ash and breaking load. Breaking load was regressed on added P intake, and the bioavailability of P was determined by the slope ratio method. The bioavailabilities of P (relative to MSP) for low-phytate and normal corn were 62 and 9%, respectively. These were similar to the determined in vitro values of 57 and 11% for low-phytate and normal corn, respectively. In the second study, 20 pigs (initial BW 20 kg) were used in a randomized complete block design with a 2 x 2 factorial arrangement of treatments. Two corn lines (low-phytate and normal) and two levels of supplemental P (0 and .2%) from dicalcium phosphate were used. Diets with no added P were formulated to contain .9% lysine, .6% Ca, and .34% P. Apparent nutrient digestibilities were calculated from total collection of urine and feces for 5 d. There were no differences among treatments for energy and nitrogen digestibility. Pigs fed low-phytate corn with no added P had increased digestibility and retention of P and reduced total P excretion (P < .05). We conclude that low-phytate corn contains at least five times as much available P as normal corn. The use oflow-phytate corn greatly reduced the amount of P excreted by the pig and increased the N:P ratio in the manure.

Direct-fed microbials (DFM) supplemented in sow diets may confer health benefits to the host and their piglets by reducing pathogens in the sow and environment. In this study we evaluated the effect of a Bacillus-based DFM on the gastrointestinal microbiota of neonatal piglets. A total of 208 sows were divided into 2 treatments: a control diet and the control diet supplemented with a Bacillus subtilis-based DFM (3.75 × 10(5) cfu/g feed). Twenty-one piglets sampled from each sow treatment group were euthanized on d 3 of lactation followed by an additional 15 piglets per treatment on d 10 of lactation. Litters from DFM-supplemented sows had greater (P = 0.02) weaning weights and a tendency (P = 0.09) for improvement in litter ADG. Sows supplemented with the DFM weaned more pigs (P = 0.06) than control sows which was reflected in numerically lower but not statistically different (P = 0.12) decrease in piglet mortality in DFM litters. Terminal RFLP was used to characterize gastrointestinal (GI) microbial populations in the ileum and colon of the piglets. Terminal restriction fragments (T-RF) were compared between control and DFM treatments. There was a greater incidence and quantity of T-RF B423 and H330 (binary P = 0.01, 0.08; quantitative P = 0.01, 0.05, respectively), putatively identified as Lactobacillus gasseri/johnsonii, in the ileum of pigs nursing sows supplemented with DFM at d 3. Terminal restriction fragment peaks B423 and H330 were also greater (binary P = 0.01, 0.08; quantitative P = 0.01, 0.01, respectively) in the colon of pigs nursing sows supplemented with DFM at d 3. Peaks M495 and B394, putatively identified as E. coli, were greater (binary P = 0.01, 0.04; quantitative P = 0.01, 0.01, respectively) in the colon of the control pigs at d 3. At d 10, both the presence and quantity of Lactobacillus species were greater (P < 0.05) in the colon of pigs with the DFM treatment. Additionally, there was a tendency for T-RF B227 and H257 (binary P = 0.07, 0.07, respectively), putatively identified as Clostridium perfringens, to be present in the ileum of the control pigs at d 10 compared with treated pigs. Results of this study reveal that the developing gastrointestinal microbiota of a neonatal piglet can be affected by DFM supplementation to the sow.

The aim of this research was to determine whether feeding gestating and lactating sows (n-3) PUFA [eicosapentaenoic acid (EPA) and/or docosahexenoic acid (DHA)] or coconut fat (saturated fat) influences ex vivo glucose absorption in the proximal jejunum and glucose and glycogen concentration of liver and muscle of their offspring at weaning. Sows were fed 1 of 4 diets for 150 d, which included the entire gestation and lactation periods. The diets consisted of basal corn/soybean meal (CONT), CONT + protected EPA and DHA-rich fish oil (PFO), CONT + DHA Gold fat (DHAGF), and CONT + coconut fat (COCO). All tissues were collected from piglets (n = 4 per treatment) following a 24-h period of food deprivation, which was initiated at weaning. Proximal jejunum samples were mounted in modified Ussing chambers for transport determinations. Relative to the CONT (7 muA/cm(2)), active glucose transport was greater (P = 0.013) in piglets from sows fed the PFO (30 microA/cm(2)) and DHAGF (40 microA/cm(2)) diets, but not the COCO diet (19 microA/cm(2); pooled SEM = 5). Likewise, jejunum expression of glucose transporter 2 and sodium glucose transporter 1 protein tended (P < 0.10) to be greater in piglets from dams fed the PFO and DHAGF diets, as did AMP-activated protein kinase activity. Piglets' muscle glycogen was greater than in CONT (34 +/- 5.2 mg/g wet tissue) only in piglets from dams fed the DHAGF (46 +/- 5.2 mg/g wet tissue; P < 0.05). These results indicate that (n-3) PUFA, particularly DHA, improves intestinal glucose absorption and muscle glycogen concentrations in newly weaned pigs. These findings may also have important implications for human mothers and infants.

The consequences of a low litter average birth weight phenotype for postnatal growth performance and carcass quality of all progeny, and testicular development in male offspring, were investigated. Using data from 25 sows with one, and 223 sows with two consecutive farrowing events, individual birth weight (BW) was measured and each litter between 9 and 16 total pigs born was classified as low (LBW), medium (MBW) or high (HBW) birth weight: low and high BW being defined as .1 standard deviation below or above, respectively, the population mean for each litter size. Litter average BW was repeatable within sows. At castration, testicular tissue was collected from 40 male pigs in LBW and HBW litters with individual BW close to their litter average BW and used for histomorphometric analysis. LBW piglets had a lower absolute number of germ cells, Sertoli cells and Leydig cells in their testes and a higher brain : testis weight ratio than HBW piglets. Overall, LBW litters had lower placental weight and higher brain : liver, brain : intestine and brain : Semitendinosus muscle weight ratios than MBW and HBW litters. In the nursery and grow-finish (GF) phase, pigs were kept in pens by BW classification (9 HBW, 17 MBW and 10 LBW pens) with 13 males and 13 females per pen. Average daily gain tended to be lower in LBW than HBW litters in lactation (P 5 0.06) and throughout the nursery and GF phases (P , 0.01), resulting in an increasing difference in body weight between LBW, MBW and HBW litters (P , 0.05). Average daily feed intake was lower (P , 0.001) in LBW than HBW litters in the nursery and GF phases. Feed utilization efficiency (feed/gain) was similar for LBW and HBW litters in the nursery, but was lower (P , 0.001) in HBW than LBW litters in the GF phase. By design, slaughter weight was similar between BW classifications; however, LBW litters needed 9 more days to reach the same slaughter weight than HBW litters (P , 0.001). BW classification did not affect carcass composition traits. In conclusion, LBW litters showed benchmarks of intrauterine growth retardation, LBW had a negative impact on testicular development and germ and somatic cell populations, and was associated with decreased postnatal growth during all phases of production; however, no measurable effect on carcass composition traits was established.

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This study was conducted to determine the effect of reduced lactation length and supplemental milk replacer (MR) during high ambient temperatures. Thirty nine primiparous and 100 multiparous sows (PIC, Franklin, KY, C-22) were used in a 2 x 2 x 2 factorial arrangement of treatments. Treatments consisted of two lactation room temperatures (21 degrees C [TN] and 32 degrees C [HOT]), two lactation lengths (14 or 19 d), and two parity groups (primiparous, multiparous). Pigs were either: 1) sow-reared to 19 d or 2) sow-reared to 14 d, and then reared to 19 d with MR after sow removal. All sows were fed the same diet (1.07% lysine, 3,366 kcal of ME/kg). Sows were weighed and ultrasound for backfat thickness (BF) and longissimus muscle area (LMA) within 6 h after farrowing and at the time of sow removal (d 14 or 19). Pigs were individually weighed at weaning (d 19) and after a 47-d nursery period (d 66). Heat stress increased sow weight loss (-13.35 kg, P < 0.01) and decreased sow feed intake (4.63 kg/d, P < 0.01) during lactation compared with sows in TN (+4.5 kg and 7.5 kg/d, respectively). Early weaning (d 14) during heat stress decreased maternal weight loss (-10.1 vs. -16.6 kg, P < 0.01). Primiparous sows lost more BF in both environments (-2.60 vs. -1.56 mm, P < 0.05), and both parity groups lost more BF (-3.35 vs. -2.3 mm, P < 0.10) and LMA (-1.82 vs. -0.77 cm2, P < 0.05) when lactating for 19 d in the HOT environment than those lactating for 14 d. Pigs nursing primiparous and multiparous sows in the HOT environment and provided MR had heavier individual 19-d weights (7.37 and 8.12 kg/ pig, respectively) than those nursing to 19 d (5.57 and 6.04 kg/pig, P < 0.01). Milk replacer decreased the difference normally observed in 19-d weights between primiparous and multiparous sow-reared pigs in TN. Pigs fed MR in both environments and nursing multiparous sows had improved weight gains in the nursery compared with pigs nursing sows to 19 d (428 vs. 406 g/d, respectively; P < 0.01), or reared by primiparous sows (444 vs. 390 g/d , respectively; P < 0.01). Sow weaning on d 14 in the HOT environment decreased the wean-to-estrus interval in primiparous sows (22.8 vs. 9.2 d, P < 0.10). This study shows the benefit of early weaning in combination with milk replacer to preserve the sow and to restore pig weaning weights and nursery end weights under heat stress.

A total of 196 barrows (88 kg) were used in a 2 x 2 factorial arrangement of treatments and housed in a facility (seven pigs per pen) where temperatures cycled between 27 and 35 degrees C. Treatments consisted of (as-fed basis) two CP levels (13.6 or 11.3%) and two levels of added fat (1 or 8%). Diets were formulated to the same true digestible lysine:ME ratio (1.68 g of lysine/Mcal of ME). Diets were fed and growth variables were measured until pigs reached 114 kg of BW. Ham and LM (loin) 24-h pH (PH24), and light reflectance (CIE L*, and a*, and b*, and hue angle) were taken after slaughter. Additionally, loins were removed and measured for i.m. fat, moisture, glycolytic potential, and subjected to a 7-d retail display evaluation that measured pH, light reflectance, and subjective color and odor score. The remaining boneless lumbar loin segment was vacuum-sealed for 14 d and subsequently measured for pH, light reflectance, and color. Pigs fed the high-CP, low-fat diet had a lower ADG than all other treatments (P = 0.06). High-fat feeding resulted in improved ADG (CP x Fat; P = 0.06) and G:F (Fat effect; P < 0.01). Higher fat and lower protein levels both increased final BF (P = 0.07). Pigs fed the low-CP diets had lower ham PH24 (P < 0.01). Loin PH24 was higher with high fat feeding (P = 0.10). Additionally, pigs fed high fat diets had lower L* values on the ham face and cut loin 24 h after slaughter (Fat effect; P

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