The Effects of Fat-soluble Vitamin Administration on Plasma Vitamin Status of Nursing Pigs Differ When Provided by Oral Administration or Injection.

Four experiments were conducted to investigate the effect of fat-soluble vitamin administration to sows or newborn pigs on plasma vitamin status. In Exp. 1 and 2, a total of 24 and 43 newborn pigs were allotted to control and vitamin treatments (vitamin D3 with variable addition of vitamins A and E) orally or by i.m. injection. In Exp. 3, pigs from Exp. 2 were allotted to 2 treatments (±vitamins D3 and E in drinking water) for 14 d postweaning. In Exp. 4, twenty-four gestating sows were used for 2 treatments (±injection of a vitamin D3/A/E product 2 wk prepartum). In Exp. 1 and 2, when vitamin D3 was administrated orally or by i.m. injection on d 1 of age, pigs had increased plasma 25-hydroxycholecalciferol (25-OH D3) concentration 10 d after administration compared with control pigs (p<0.05). The injectable administration with vitamin D3 and E was able to achieve higher plasma 25-OH D3 (p<0.05) and α-tocopherol (p<0.05) concentrations than oral administration. At weaning, the pigs in the injection group had higher plasma 25-OH D3 concentration than those in the other groups in both studies (p<0.05). In Exp. 3, water supplementation of vitamin D3 and E postweaning increased plasma 25-OH D3 and α-tocopherol concentrations at d 14 postweaning (p<0.01). In Exp. 4, when sows were injected with the vitamin D3 product prepartum, serum 25-OH D3 concentrations of sows at farrowing (p<0.01), and in their progeny at birth (p<0.01) and weaning (p<0.05) were increased. These results demonstrated that fat-soluble vitamin administration to newborn pigs increased plasma 25-OH D3 concentration regardless of administration routes and α-tocopherol concentration by the injectable route, and that water supplementation of vitamin D3 and E to nursery pigs increased plasma 25-OH D3 and α-tocopherol concentrations. Additionally, injecting sows with vitamin D3 prepartum increased 25-OH D3 in sows and their offspring. If continued research demonstrates that the serum levels of 25-OH D3 are critical in weanling pigs, a variety of means to increase those levels are available to swine producers.

Temporal plasma vitamin concentrations are altered by fat-soluble vitamin administration in suckling pigs.

Piglets are born with purportedly low plasma vitamin D levels. The objective of this study was to investigate the effect of fat-soluble vitamin administration, primarily vitamin D, by different administration routes on plasma vitamin concentrations in suckling pigs. A total of 45 pigs from 5 litters were allotted at birth to 3 treatments within each litter. Pigs were administered 400 IU of α-tocopherol, 40,000 IU of retinyl palmitate, and 40,000 IU of vitamin D at d 1 of age either orally or by i.m. injection and compared with control pigs with no supplemental vitamin administration. Blood samples were collected at d 0 (initial), 1, 2, 3, 4, 6, 9, 14, and 20 after administration. Plasma 25-hydroxycholecalciferol (25OHD), α-tocopherol, retinyl palmitate, and retinol concentrations were analyzed. Except for retinol, the effects of treatment, day, and day × treatment interaction ( < 0.01) were observed on plasma vitamin concentrations. Plasma concentrations of 25OHD and α-tocopherol increased immediately regardless of administration routes to peak at d 2 and 1 after administration, respectively. Plasma retinyl palmitate concentrations increased only with the injection treatment, with the peak at d 1 after administration. Plasma concentrations of 25OHD in both administration treatments and α-tocopherol in the injection treatment were maintained at greater levels than those in the control treatment until d 20 after administration. With regard to the pharmacokinetic parameters for plasma 25OHD concentrations, the injection treatment had greater elimination half-life ( < 0.01), maximum plasma concentrations ( < 0.05), and all area under the curve parameters ( < 0.01) but a lower elimination rate constant ( < 0.01) than the oral treatment. Relative bioavailability of oral administration compared with injection administration was 55.26%. These results indicate that plasma status of 25OHD,α-tocopherol, and retinyl palmitate are differentially changed between types of vitamins administered and between administration routes and that the injection route had a greater increase and slower disappearance of plasma vitamin levels than the oral route during the suckling period.

Efficacy of a copper-lysine complex as a growth promotant for weanling pigs.

Eight 28- or 35-d experiments involving, 1,301 crossbred pigs weaned at 30 +/- 2 d of age (7.0 to 7.9 kg initial weight) were conducted to evaluate the efficacy of a Cu-lysine complex (CuLys; CuPLEX 80 in Exp. 1 to 5, and CuPLEX 100 in Exp. 6 to 8) at dietary concentrations of 50, 100, or 200 ppm as a growth promoter for weanling pigs. CuPLEX 80 contained 50% Cu in the complexed from (1 mol Cu:2 mol lysine) and 50% Cu as CuSO4.5H2O (CuSO4). All the Cu in CuPLEX 100 was in the complexed form. In general, the addition of Cu from CuSO4 or either CuLys source improved pig performance. Overall, averaged across Cu sources, there were no differences between 100 and 200 ppm of Cu in the magnitude of improvement over controls for daily gain (14.0 vs 14.3%), daily feed (12.1 vs 10.7%), or feed:gain ratio (1.6 vs 3.0%). Averaged across levels of Cu supplementation, the percentage improvements from CuLys additions were greater than those for CuSO4 for growth rate (16.8 vs 11.5%; P < .03) and feed intake (14.1 vs 8.7%' P < .01), but not for efficiency of feed utilization (2.2 vs 2.4%). These trends were similar for both sources of CuLys. Liver Cu concentrations of pigs receiving 200 ppm of Cu in the totally complexed form (CuPLEX-100) were lower (P < .025) than concentrations in those receiving 200 ppm of Cu from CuSO4 (111 vs 221 ppm).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino acid supplementation of meat meal in lysine-fortified, corn-based diets for growing-finishing pigs.

Three experiments involving 320 Yorkshire x Hampshire pigs were conducted to assess the effects of L-tryptophan additions to meat meal-supplemented, corn-based diets on rate and efficiency of growth of growing-finishing pigs. The meat meal used in Exp. 1 and 2 was a blend from two sources and that used in Exp. 3 was from a single source. A fortified corn-soybean meal basal diet (13.3% CP during the growing stage; 11.7 or 12.0% CP during the finishing stage), supplemented with .15 to .20% lysine (as L-lysine.HCl), was fed in each experiment. This diet was formulated to be adequate in dietary lysine (.75 to .80% during the growing stage; .65 to .71% during the finishing stage). Meat meal was added at 5 to 10% and was substituted for corn and soybean meal on a lysine basis. Diets containing meat meal were then supplemented with various levels (0 to .05%) of L-tryptophan. Levels of Ca and P were approximately the same across treatments, with levels based on the amounts provided by the highest level of meat meal in the diets. The pigs initially averaged 24, 29, and 45 kg of BW in the three experiments, and they were on test until they reached market weight (93 to 101 kg of BW). Pigs were switched from the growing to the finishing diet at 57 and 61 kg in Exp. 1 and 2, respectively. Feed intake, growth rate, and efficiency of feed utilization were reduced when meat meal was included in the diet, particularly at the higher dietary inclusion (10%).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of the dietary inclusion of copper and(or) antibiotics on the performance of weanling pigs.

Five trials involving 518 pigs were conducted to determine the effects of the dietary addition of copper (0 or 250 ppm as copper sulfate) with and without antibiotics (55 ppm chlortetracycline, CTC, or 27.5 ppm virginiamycin VIR) on the rate and efficiency of gain and survival of early-weaned pigs. The experimental animals consisted of all pigs weaned from each of 67 litters at 28 +/- 2 days of age, regardless of weight or condition. In trials 1 through 4, single additions of copper, CTC or VIR to the corn-soybean meal-based diet improved (P less than .05) daily gains by 22, 22 and 17%, respectively, and feed to gain ratios by 5.1, 8.9 and 8.2% compared with those of pigs fed the unsupplemented diet during the 28-day trials. However, only the addition of copper to the diet increased (P less than .05) postweaning pig survival. Dietary inclusion of both copper and an antibiotic (CTC or VIR) further improved daily gains (P less than .05) by 10 to 11% and feed to gain ratios by 2 to 5% compared with the single addition of each antimicrobial agent. In trial 5, 125 ppm of copper were found to optimize daily gain and feed intake, whereas 250 ppm were required to maximize pig survival. These data demonstrate that high levels (125 to 250 ppm) of dietary copper increase the growth rate and reduce the incidence of mortality among weanling pigs. The data also indicate that the growth-promoting effects of copper and CTC, a broad spectrum antibiotic, or VIR, a gram-positive antibiotic, are additive in nature.

Effects of dietary additions of 1,3-butanediol or lard for sows on survival of neonatal pigs.

In nine trials, 278 late-term gravid sows were fed isocaloric amounts (8,500 kcal metabolizable energy (ME)/d) of a fortified, corn-soybean meal based diet in which 20% of their daily ME intake was supplied by corn starch, 1,3-butanediol or lard from about d 106 of gestation to parturition. After parturition, the sow's daily ME intake was increased to 18,000 kcal. Sows fed starch and lard remained on their respective diets for the duration of a 28-d lactation; whereas, those initially fed butanediol were switched to the starch diet after parturition. Number of pigs born per litter, average pig birth weight and incidence of stillbirths were not influenced (P greater than .30) by the prepartum diet of the sow. However, the inclusion of isocaloric levels of butanediol for starch in the preparatum diet and lard for starch in the pre- and postpartum diets increased the number of pigs weaned per litter by .45 (P less than .13) and .16 pigs (8.25, 7.96 vs 7.80) and improved the survival rate of pigs from birth to weaning by 4.3 (P less than .13) and 2.7 percentage units (84.5, 82.8 vs 80.1%), respectively. Average pig weights at 28 d of age for litters of sows fed butanediol prepartally were similar to those of sows fed starch, but were less (P less than .01) than those of sows fed lard throughout lactation.

Effects of prepartum administration of 1,3-butanediol to sows on growth and survival of neonatal pigs.

In six trials, 158 late-term gravid sows were fed isocaloric amounts (8,500 kcal metabolizable energy/d) of a corn-soybean meal-based diet in which 20% of their daily metabolizable energy (ME) intake was supplied by either cornstarch or 1,3-butanediol (butanediol) from about d 105 of gestation to parturition. After parturition, all sows were allowed to consume a standard, corn-soybean meal-based lactation diet, ad libitum, during a 28-d lactation. Prepartum administration of butanediol, a stable, nonvolatile liquid that possesses anesthetic, antimicrobial and ketogenic properties, did not alter the voluntary feed intake or body weight changes of sows pre- or post-partum. Number of pigs born per litter, average pig birth weight and incidence of stillbirths were not influenced by the prepartum diet of the sows. However, the addition of butanediol to the prepartum diet increased (P less than .10) the number of pigs weaned per litter at 28 d by .51 pigs (8.17 vs 7.66) and improved (P less than .10) the survival rate of pigs from birth to weaning by 5.7 percentage units (84.1 vs 78.4%) compared with those of sows fed isocaloric additions of starch. Average pig weights at 28 d of age were similar for the two treatment groups (6.18 vs 6.08 kg) even though greater numbers of pigs were nursing sows fed the butanediol diet prepartum. The rate and efficiency of gain and survivability of weanling pigs during a 28-d postweaning period were not influenced by the prepartum diet of their dam.

Effects of source and level of copper on performance and liver copper stores in weanling pigs.

Five 28- to 33-d experiments involving 460 crossbred pigs weaned at 28 +/- 2 d of age (initial weight, 6.7 to 8.1 kg) were conducted to determine the effects of feeding high dietary levels of Cu sulfate (CuSO4) or Cu oxide (CuO) on rate and efficiency of gain and liver Cu stores of weanling pigs. The pigs were housed in groups of five to six/pen and fed a fortified, unmedicated, corn-soybean meal-dried whey basal diet (1.1% lysine, 30 ppm Cu). In Exp. 1 and 2, pigs (eight replicates) were fed the basal or the basal plus 125 or 250 ppm Cu from CuSO4 or CuO for 28 d. In Exp. 3 and 4, four replications were fed the same diets as in Exp. 1 and 2 plus two additional diets (500 ppm Cu from CuSO4 or CuO). In Exp. 5, dietary levels of 0, 125, 250, 375 or 500 ppm Cu from CuSO4 were evaluated using four replications. At the end of each experiment, the liver from one pig in each pen was collected for Cu analysis. Overall, rate and efficiency of gain were improved (P less than .01) by feeding 125 or 250 ppm Cu as CuSO4, with the 125 ppm dietary level being about 75% as effective in stimulating growth as 250 ppm. Performance of pigs was not different from controls when the highest (500 ppm) level of Cu (from CuSO4) was fed. Liver Cu increased 10- to 70-fold when 250 to 550 ppm Cu from CuSO4 was included in the feed.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term effects of feeding a high copper diet to sows during gestation and lactation.

An experiment was conducted to assess the long-term effects of feeding a high Cu diet to sows during gestation and lactation. Fifty-five gilts averaging 152 kg BW and 10.3 mo of age were allotted on d 47 after mating to diets consisting primarily of corn and soybean meal and containing 0 to 250 ppm of added Cu (as CuSO4.5H2O). Both diets contained 8.8 ppm of Cu from the trace mineral mix, and both contained antibiotics (55 mg/kg of chlortetracycline in the gestation diet, 110 mg/kg each of neomycin and oxytetracycline in the lactation diet). Sows continued on their respective diets throughout gestation and lactation, until culled from the herd or until they farrowed their sixth litter. Feed intake averaged 1.90 kg/d during gestation and 4.82 kg/d during lactation. A total of 86 and 81 litters were farrowed by control and Cu-treated sows, respectively. Seven control and eight treated sows completed six parities. Farrowing rate (no. farrowed/no. bred) was less (P < .05) in gilts fed high Cu, but culling rate was reduced (P < .01) in sows receiving the high Cu diet. Sows fed high Cu diets were heavier in BW on d 108 of gestation before their second (P < .05) and third to fifth litters (P < .01) than controls. Sows fed high Cu diets farrowed larger litters of pigs (P < .10) and the pigs were 9% heavier at birth (P < .001) and 6% heavier at weaning (P < .01) than pigs from control sows.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of phytase in improving the bioavailability of phosphorus in soybean meal and corn-soybean meal diets for pigs.

Four experiments involving 225 pigs were conducted to assess the efficacy of a microbial phytase (FINASE, Alko Ltd. Biotechnology, Rajamäki, Finland) produced by Aspergillus niger in corn-soybean meal or dextrose-cornstarch-soybean meal-based diets. In two experiments with growing-finishing pigs, fortified corn-soybean meal diets were formulated to be adequate (.50%) or inadequate (.40 or .30%) in P during the growing phase followed by adequate (.40%) or inadequate (.30%) P in the finishing phase. Mono-dicalcium phosphate was the source of supplemental P. Half the diets were supplemented with phytase (500 phytase units/g). Rate and efficiency of gain and bone breaking strength were decreased when P-deficient diets were fed. Phytase supplementation of the low-P diets restored growth rate and feed:gain to levels that approached those of pigs fed the adequate-P control diet. Bone strength was partially restored to that of the controls. In two additional experiments, pigs were fed low-P basal diets in which all the dietary P came from soybean meal or a corn-soybean meal blend. Both diets contained .05% available P. Graded levels of monosodium phosphate were added to these diets, up to .15% added P, to establish a standard curve. Phytase was added to the basal diet at 250, 500, or 1,000 units/g. Growth rate and bone strength improved linearly (P < .01) with added monosodium phosphate and with increasing levels of supplemental phytase. Based on estimates of total and available P intakes, the highest level of phytase (1,000 units/g) increased the bioavailability of the P from 25% in the soybean meal diet to 57% in the phytase-supplemented diet, and from 15% in the corn-soybean diet to 43% in the phytase-supplemented diet. Expressed on the basis of the improvement in phytate P availability, this level of phytase converted approximately one-third of the unavailable P to an available form. The results indicate that the phytase was efficacious in improving the bioavailability of phytate P for pigs.

Efficacy of a recombinant-derived phytase in improving the bioavailability of phosphorus in corn-soybean meal diets for pigs.

Three experiments involving 162 pigs were conducted to assess the efficacy of phytase (Natuphos; BASF, Mount Olive, NJ) in low-P, corn-soybean meal-based diets. The phytase was produced by a recombinant Aspergillus niger. The phytase supplement contained 5,000 phytase units (PTU)/g. In Exp. 1 (66 pigs) and 2 (60 pigs), growing-finishing pigs were fed fortified corn-soybean meal diets formulated to be adequate (.50%), marginal (.425%), or inadequate (.35%) in P during the growing phase (23 to 60 kg BW) followed by adequate (.40%), marginal (.35%), or inadequate (.30%) P, respectively, during the finishing phase (to 104 kg BW). Dicalcium phosphate was the source of supplemental P. In addition, the low-P sequence (.35/.30% P) was supplemented with phytase at 250, 500, or 1,000 PTU/kg. Rate and efficiency of gain decreased linearly (P < .01) and bone breaking strength decreased quadratically (P < .01) as the concentration of P was decreased in the diets. Responses in growth and bone traits to increasing levels of phytase activity in the low-P diet were linear (P < .01). The highest level of phytase in the low-P diet restored growth rate and bone breaking strength to levels that approached or met those of pigs fed the adequate P diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of low-activity, microbial phytase in improving the bioavailability of phosphorus in corn-soybean meal diets for pigs.

Two experiments involving 115 pigs were conducted to assess the efficacy of a microbial phytase (Allzyme Phytase; Alltech, Nicholasville, KY) produced by Aspergillus niger in low-P, corn-soybean meal-based diets. The phytase supplement contained 50 phytase units/g and 1.43% P. In Exp. 1, growing-finishing pigs were fed fortified corn-soybean meal diets formulated to be adequate (.50%) or inadequate (.30%) in P during the growing phase (38 to 57 kg BW) followed by adequate (.40%) or inadequate (.30%) P, respectively, during the finishing phase (to 101 kg BW). Dicalcium phosphate was the source of supplemental P. Half the diets were supplemented with phytase at 500 phytase units/kg. Rate and efficiency of gain and bone breaking strength were decreased (P < .01) when the low-P diet was fed. Adding phytase to the low-P diet restored performance and bone breaking strength (P < .01) to levels that approached those of pigs fed the adequate-P diet. In Exp. 2, growing pigs (13 kg BW), were fed a low-P (.32% total P; .048% available P) based diet supplemented with graded levels of monosodium phosphate to provide 0, .075, and .15% added P or with phytase to supply 250, 500, 1,000, or 2,000 phytase units/kg. Chromic oxide was included as an indigestible marker for determining apparent absorption and fecal excretion of P. Performance and bone strength increased linearly with added monosodium phosphate (P < .01) and with increasing levels of supplemental phytase (P < .05). A portion of these increases from phytase was attributed to the P supplied by the phytase mix (.007, .014, .028, .057%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Tribasic copper chloride and copper sulfate as copper sources for weanling pigs.

We conducted three 28-d experiments involving a total of 915 pigs to assess the relative efficacy of tribasic Cu chloride (Cu2[OH]3Cl) and Cu sulfate pentahydrate (CuSO4.5H20) in diets for weanling pigs. Experiments 1 and 2 were conducted at an experiment station (University of Kentucky), and Exp. 3 was conducted at a commercial feed company's swine research facilities (United Feeds, Inc.). The basal diet was a fortified corn-soybean meal-dried whey diet (1.25% lysine) with no antimicrobials in Exp. 1 or with carbadox (55 mg/kg) in Exp. 2 and 3. In Exp. 1, 135 pigs were weaned at 27 to 31 d and fed the basal diet without or with 100 or 200 ppm Cu from Cu chloride, or 100 or 200 ppm Cu from Cu sulfate from 7.9 to 17.7 kg BW. The 200 ppm level of Cu from Cu sulfate improved ADG (P < .10), and both levels of Cu from Cu chloride tended to improve feed:gain. In Exp. 2, 150 pigs were weaned at 27 to 31 d and fed the basal diet without or with 100, 150, or 200 ppm Cu from Cu chloride, or 200 ppm Cu from Cu sulfate from 8.9 to 20.8 kg BW. Addition of 200 ppm Cu improved ADG (P < .08) and ADFI (P < .01), but not feed:gain. Source of Cu did not affect performance. In Exp. 3, 630 pigs were weaned at 16 to 20 d and fed a common diet for 10 to 12 d until the start of the experimental period. The same experimental diets as used in Exp. 2 were fed from 9.1 to 25.5 kg BW. Both Cu sources improved ADG (P < .01), and sources and levels of Cu did not differ. Liver Cu increased in pigs fed 200 ppm Cu, and Cu sulfate tended to increase liver Cu more than did Cu chloride in one experiment, but not in another experiment. The results indicate that tribasic Cu chloride is as effective as Cu sulfate in improving growth in weanling pigs.

Effect of chromium tripicolinate supplementation on porcine immune response during the postweaning period.

A total of 60 pigs from 15 litters were used during two experiments to assess the effects of maternal supplementation of Cr tripicolinate on performance and immune status of the offspring during the first 42 d after weaning. Gilts were raised on diets with either 0 (-Cr) or 200 (+Cr) ppb supplemental Cr from Cr tripicolinate. Their offspring were weaned at about 23 d of age. Pigs from dams fed supplemental Cr were fed Cr-supplemented diets after weaning and pigs from unsupplemented dams were not fed supplemental Cr. Pigs were housed in groups of three according to litter origin (six -Cr and nine +Cr) and BW. Feed and water were available for ad libitum consumption. Serum was collected 24 h after birth, the day after weaning (d 0), and, subsequently, every 7 d through d 28 for measurement of total immunoglobulin (Ig) G and IgM. For the 42-d nursery period, ADG (511 and 531 g/d for -Cr and +Cr, respectively), ADFI (827 and 851 g/d), and gain:feed (0.62 and 0.62) were not affected (P > 0.15) by Cr. Total IgG was not affected (P > 0.10) by Cr on d 0 (7.6 and 7.7 mg/mL for -Cr and +Cr, respectively) or on d 7 (6.3 and 6.1 mg/mL for -Cr and +Cr, respectively), when the lowest concentrations were observed. By d 28, total IgG had risen (11.7 and 8.9 mg/mL for -Cr and +Cr, respectively) and was affected by Cr (P = 0.03). Total IgM followed a similar pattern and was lowest on d 7. In each trial, IgG at 24 h after birth was inversely related to IgG from d 14 through 28 in the nursery. Additionally, the lowest Ig concentrations occurred between 4 and 5 wk of age, rather than at weaning (23 d of age); this may represent a vulnerable period for weanling pigs. Supplementation of the weanling pig diets with Cr tripicolinate did not significantly affect performance and immune status during the postweaning period.

Effect of chromium tripicolinate supplementation on porcine immune response during the periparturient and neonatal period.

A total of 36 gilts were used to assess the effects of Cr tripicolinate supplementation on immune response in sows and their offspring during the periparturient and neonatal period. Gilts were raised from weaning to reproductive age on diets with either 0 (-Cr) or 200 (+Cr) ppb supplemental Cr from CrPic. Subsequently, 22 gilts (9 -Cr and 13 +Cr) in parity 1 and 16 sows in parity 2 (7 -Cr and 9 +Cr) underwent immune status testing. Only sows that completed all procedures in parity 1 were included in parity 2. Sows were immunized with ovalbumin about 3 wk (d 0), and again 14 d later for gilts, prior to anticipated farrowing, and serum was collected on d 0 and at 14-d intervals for a total of four samples. Serum was collected from five to six pigs/litter at 24 h after birth, three or six pigs/litter the day after weaning (25 d of age) in parity 1, and three pigs/litter the day of weaning (20 d of age) in parity 2. Milk was collected at 1 h (colostrum), 6.5 d (early), and 19 d (late) after farrowing. The only effect of Cr on total immunoglobulin (Ig) concentration was on sow serum IgG (21.7 and 24.1 mg/mL for -Cr and +Cr, respectively; P = 0.08) and IgM (11.0 and 12.5 mg/mL; P = 0.06) on d 0. No effect (P > 0.15) of Cr was observed on the IgG antibody response to ovalbumin, but Cr was associated (P < 0.10) with a decreased IgM antibody response to ovalbumin beginning on d 14. In parity 2, colostral total IgG increased (80.6 and 92.4 mg/mL for parity 1 and 2, respectively; P = 0.06), which was reflected in the neonates at 24 h after birth (33.6 and 39.7 mg/mL; P = 0.01) and at weaning (7.3 and 13.3 mg/mL; P < 0.001). Supplementation of Cr tripicolinate had minimal effects on humoral antibody response of the dam or its transfer to the neonate; however, parity greatly influenced the concentrations of immunoglobulins in the milk and their transfer to the neonate.

Feeding value of an enzymatically digested protein for early-weaned pigs.

Weanling pigs were used in a series of studies to determine the feeding value of an enzymatically digested protein product developed from a blend of swine and poultry abattoir by-products. The initial study used 156 pigs weaned at approximately 22 d of age to compare the product with menhaden fish meal in Phase II diets. The product supported equal growth rate, and there was no preference for diet exhibited based on inclusion level of the enzymatically digested protein product. The second study used 100 pigs weaned at approximately 21 d of age to compare the product with spray-dried animal blood cells in Phase II diets. The product supported a growth rate equal to that with the blood cells, and the combination of products enhanced growth rate (P<.05). The third study used 265 pigs to compare the product with spray-dried porcine plasma in a slope ratio growth assay. Results demonstrated a relative feeding value of 91% for the product over a 4-wk feeding period. The fourth study used 290 pigs to compare the product with spray-dried porcine plasma in Phase II diets; results demonstrated comparable growth performance. The final study used 180 pigs to compare the product with spray-dried porcine plasma in Phase I diets; results demonstrated comparable growth performance. These data indicate that the enzymatically digested abattoir by-product is a high-quality protein source for weanling pigs.

Recombinant porcine somatotropin for sows during late gestation and throughout lactation.

Two experiments were conducted to evaluate whether administration of recombinant porcine somatotropin (pST) to sows (Hampshire-Yorkshire) enhanced lactational performance. In Exp. 1, sows (n = 84) were fed a corn-soybean meal diet (17.8% CP), or a similar diet with 8% added fat, from d 108 of gestation to d 28 of lactation. Half of the sows fed each diet were injected with 6 mg/d of pST from d 108 of gestation to d 24 of lactation. Diets were fed at 2.27 kg/d from d 108 of gestation until farrowing and then were self-fed during lactation. By d 3 of lactation, litter size was standardized at 8 to 10 pigs per litter. Treating sows with pST resulted in a 10-fold increase (P less than .001) in serum somatotropin at 4 h postinjection. Serum glucose was increased (P less than .01) and serum triglycerides, creatinine, and urea N were decreased (P less than .01) by pST. During the summer, apparent heat stress occurred in pST-treated sows, resulting in 14 deaths. Most (10) of the deaths occurred just before, during, or shortly after farrowing. Fewer (P less than .08) deaths occurred when pST-treated sows were fed the diet with added fat. Sows treated with pST consumed less feed (P less than .10) and lost more backfat (P less than .10) during lactation than controls. Increasing the dietary fat did not prevent these changes. Weaning weights of pigs and milk yield of sows (estimated by deuterium oxide dilution) were not affected by pST treatment. In Exp. 2, sows (n = 42) were injected weekly with 0 or 70 mg of pST on d 3, 10, 17, and 24 of lactation. Litters were standardized by d 3 at 8 to 10 pigs, and sows were fed the same control (low fat) diet as in Exp. 1. Sows treated with pST consumed less feed and lost more weight and backfat during lactation than untreated sows. Litter size, average pig weaning weights, and milk yield were not influenced by pST treatment. These data indicate that a 6-mg daily injection of pST from 6 d prepartum to d 24 of lactation or a 70-mg weekly injection of pST from 3 d postpartum to d 24 of lactation does not increase milk production in lactating sows.

Effect of chromium source on tissue concentration of chromium in pigs.

The concentration of Cr in several tissues in response to high-level, short-term supplementation was used to determine the relative bioavailability among 4 organic Cr sources and to assess the relative safety of high levels of supplementation. Crossbred pigs (n = 40; mean BW = 48.1 +/- 0.9 kg) were allotted to 5 diets: a control diet with no added Cr, or 5,000 microg/kg of Cr from Cr tripicolinate (CrTP), Cr propionate (CrPrp), Cr methionine (CrMet), or Cr yeast (CrY). Twenty gilts were housed individually and barrows were housed in pairs. Average duration of feeding before slaughter was 75 d. For the total experiment, pigs fed the unsupplemented diet had less ADG than pigs fed CrY (P < 0.05). Serum clinical chemistry values, obtained during the final week of the experiment, demonstrated few effects with no responses that would raise concern about metabolic changes in response to the Cr sources. The effects of the forms of Cr fed on carcass measurements and meat quality were also minimal. All Cr sources reduced cooler shrink (P < 0.05) and most resulted in some meat color change on d 1 postslaughter. For tissue Cr content, 4 of 5 tissues (bone, kidney, liver, and ovary) were increased (P < 0.05) in Cr content by supplementation with CrTP and CrMet, whereas only 2 tissues (bone and kidney) were increased (P < 0.05) by CrY, and none were increased by CrPrp. In all tissues of response, CrTP exceeded CrMet and CrMet exceeded CrY. Comparing the relative increase in tissue Cr for all responsive tissues (bone, kidney, liver, and ovary) gave a range of responses, for which the mean bioavailability relative to CrTP across tissues was 13.1% for CrPrp (0.2 to 19.0%), 50.5% for CrMet (36.2 to 79.1%), and 22.8% for CrY (2.5 to 47.9%). In summation, these results show very clear Cr effects on multiple tissues, which is conclusive evidence of absorption and deposition. The lack of a negative response in growth performance, carcass measures, and clinical chemistry at the increased quantities used herein provides assurance that normal quantities of addition are extremely safe.