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The objective of this study was to determine possible synergistic effects of supplementing one of three fungal phytases: Aspergillus fumitagusPhyA (AFP), A. nigerPhyA (ANP), or Peniophora lyciphytase (PLP) with an Escherichia coliAppA phytase (EP) in diets for pigs. Three experiments, each lasting for 4 wk, were conducted with a total of 106 weanling pigs (5 wk old). The corn-soybean meal basal diet (BD) contained no supplemental inorganic P. In Exp. 1, 35 pigs (8.6 ± 1.0 kg BW) were fed (as-fed basis) BD + AFP at 750 U/kg of feed, BD + inorganic P (0.2% P), or BD + PLP at 500, 750, or 1,000 U/kg feed. Pigs fed BD + AFP or BD + 0.2% P had higher (P< 0.05) plasma inorganic P concentrations than those fed BD + PLP at the end of the trial (wk 4). In Exp. 2, 35 pigs (8.1 ± 0.9 kg BW) were fed BD + AFP, EP, PLP, a 1:1 mix of AFP:EP, or a 1:1 mix of PLP:EP at 500 U/kg. Pigs fed the AFP:EP mixture had growth performance and plasma measures similar to those fed either enzyme alone. Pigs fed the PLP:EP mixture had lower (P< 0.05) plasma alkaline phosphatase activity than those fed BD + PLP. Pigs fed BD + PLP had lower (P< 0.05) plasma inorganic P concentrations than pigs fed BD + EP, and higher (P< 0.05) plasma alkaline phosphatase activity than all other groups at wk 4. In Exp. 3, 36 pigs (9.1 ± 1.2 kg BW) were fed BD + ANP, EP, or a 1:1 mix of ANP:EP at 500 U/kg feed. Pigs fed the two enzymes together had lower (P< 0.05) plasma inorganic P concentration than those fed BD + EP and lower (P< 0.05) plasma alkaline phosphatase activity than pigs fed BD + ANP at wk 4. In conclusion, although the four phytases showed different effects on plasma P status of weanling pigs, there was no synergistic effect between any of the three fungal phytases and the bacterial phytase on the plasma measures or growth performance under the conditions of the present study.

Pregnant gilts (n = 126) were assigned randomly to 12 0.4-ha old world-spar bluestem (Bothriochloa ischaemum) pastures in an outdoor swine (Sus scrofa) production system to examine effects of stocking rates (17.5 or 35 gilts/ha; 7 or 14 gilts per pasture) and dietary N on percentage of ground cover, soil nitrate (NO3-) concentration, and reproductive performance. Treatments were arranged factorially with two stocking rates and two diets equivalent in dietary lysine but different in CP (control = 14.7% CP vs experimental = 12.6% CP) with three pastures per treatment. The experiment was repeated during a second parity with the same animals on the same treatments. Each triangular gestation pasture was subdivided into three regions: 1) near the point or radial center; 2) the middle region that contained a hut and a wallow area; and 3) the outer section where gilts were fed each day. Soil samples (15 cm deep) were taken at the beginning and end of the 306-d study, and soil nitrate-N concentrations were determined. Percentage of ground cover was visually estimated initially and every 30 d thereafter through d 306. Before farrowing, gilts were moved to identical pastures for farrowing and were fed a common 16% CP sorghum (Sorghum bicolor)-based lactation diet beginning at the time of movement to the farrowing pasture. Pregnant gilts were weighed at the time of assignment to treatments in the gestation pastures, when they were moved to farrowing pastures, and at weaning. Production data included total number of pigs born per sow, number of pigs born alive or dead, average birth weight, number of pigs weaned, average weaning weight, and mortality. No differences (P > 0.05) were observed between treatments in soil NO3- concentrations. Percentage of ground cover was decreased (P < 0.01) by the higher stocking rate when grazing was initiated in March/April but recovered rapidly after removal of pigs. More (P < 0.01) pigs were weaned per sow (8.4 vs 7.1+/-0.34) from higher gestation-stocking rate groups. Pig mortality in farrowing was greater (P < 0.05) for lower gestation-stocking rates (25.7% vs. 18.1+/-1.9%). A stocking rate of 35 sows/ha might have increased production potential but was associated with a rapid loss of ground cover during spring.

The perinatal development of the brain is highlighted by a growth spurt whose timing varies among species. The growth of the porcine cerebrum was investigated from the third trimester of gestation (70 days postconception) through the first 3.5 weeks of postnatal life (140 days postconception). The shape of the growth curves for cerebrum weight, total protein mass, total cell number (estimated by DNA content), and myelination (estimated by cholesterol accretion) were described. The growth velocity of cerebrum weight had two peaks, one at 90 days and the other at 130 days postconception, whereas that of total protein was greatest from 90 to 130 days postconception, and that of total DNA was greatest between 90 and 110 days and again at 130 days postconception. The growth velocity for total cholesterol continued to increase during the entire period, suggesting that myelination continued after the growth spurts for cells (protein and DNA). The growth velocity patterns observed in these contemporary pigs suggest that this species may be an appropriate model for human brain development, not only in the perinatal pattern of increase in mass of the cerebrum, as established previously, but also with regard to the patterns of cellular development and myelination.

Three experiments were conducted with 96 growing Landrace × Yorkshire × Duroc crossbreds to determine the collective effectiveness of cereal phytase from wheat middlings, microbial phytase, and citric acid in improving phytate-P bioavailability in corn-soy diets. In Exp. 1, 40 gilts (7 wk old) were fed five diets for 8 wk. Diets 1, 2, and 3 were low-P, corn-soybean meal diets (CSB) + 0, .1, or .2% inorganic P (Pi) as calcium phosphate, respectively. Diet 4 was a similar corn-soy diet that included 15% wheat middlings (461 cereal phytase U/kg). Diet 5 was the CSB + microbial phytase (1,200 U/kg; Natuphos, BASF, Mount Olive, NJ). In Exp. 2, 16 barrows (8 wk old) were fed two diets for 6 wk. Diet 1 was the same as Diet 3 of Exp. 1 (.2% Pi). Diet 2 was Diet 4 of Exp. 1 + microbial phytase (300 U/kg). In Exp. 3, 40 barrows and gilts (6 wk old) were fed four diets for 6 wk. Diets 1 and 2 were the same as those in Exp. 2. Diet 3 was Diet 2 of Exp. 2 + 1.5% citric acid. Diet 4 was similar to Diet 3 but contained 10 instead of 15% wheat middlings. In Exp. 1, pigs fed the low-P, CSB (Diet 1) had lower (P< .05) ADG, ADFI, plasma Piconcentration, bone strength, and mobility score than pigs of the other four treatments. Measurements for pigs fed the 15% wheat middlings diet were not significantly different from those of pigs fed the CSB + .1% Pior microbial phytase. In Exp. 2, ADG (P=.06) during wk 1 to 3 and gain:feed ratio (P< .02) and plasma Piconcentration (P< .005) during all weeks favored pigs fed the CSB + .2% Picompared with the other diet including 15% wheat middlings. In Exp. 3, identical ADG during all weeks and similar plasma Piconcentrations at wk 4 and 6 were observed between pigs fed the two citric acid diets (Diets 3 and 4) and the CSB + .2% Pi(Diet 1). Pigs fed Diet 4 (10% wheat middlings) had even higher (P< .02) gain:feed ratio during wk 1 to 3 than those fed Diet 1. It seems feasible to completely replace calcium phosphate with 10 to 15% wheat middlings, 300 U microbial phytase/ kg, and 1.5% citric acid in the corn-soy diets for growing pigs.

Twenty-eight young adult boars (age 7 to 8 mo) genetically selected for four generations for high (HG) or low (LG) plasma cholesterol were studied to assess dietary and genetic effects and their interactions on cholesterol metabolism. Boars within a genetic group were paired according to their plasma cholesterol concentration at 8 wk of age and were fed for 15 wk (2.7 kg/d) one of two diets (16.5% fat and 1,156 mg of cholesterol/kg diet, HD; or 3.1% fat and 0 cholesterol diet, LD) in a 2 × 2 factorial arrangement. Plasma total cholesterol (P< .01) and HDL-cholesterol (P< .01) concentrations were higher in boars fed HS (P< .01) and in HG boars (P< .01). There was a trend toward a diet × genotype interaction for plasma HDL-cholesterol (P< .06). Plasma insulin concentration tended to be lower in boars fed HD (P< .09) or HG boars (P< .10). There was a diet × genotype interaction for plasma glucagon (P< .04) concentration and a trend toward an interaction for insulin (P< .07). After 15 wk, all boars were killed by electrocution and exsanguination and measurements were taken. Backfat thickness was greater (P< .01) and carcass length (P< .01) and weights of the four lean cuts (P< .02) were lower in LG than in HG boars. No microscopic atherosclerotic plaques were observed in aorta or coronary arteries. Cholesterol concentration in subcutaneous fat was lower (P< .04) in LG boars, suggesting that cholesterol content of depot fat can be reduced by genetic selection in swine.

Influences of genotype and sex on responses to porcine somatotropin (pST) administered by daily injection were examined in genetically lean and obese gilts and barrows. Pigs (59 ± 1.4 kg BW, eight per pST dose × line × sex) were injected daily with pST at doses of 0, 2, and 4 mg/d for 6 wk. Administration of pST induced dose-dependent decreases in feed intake and rate of backfat deposition, whereas rate and efficiency of gain were increased in a quadratic manner indicating that 4 mg of pST/d approached the optimal dose. These live measures of growth were also influenced (P< .05) by sex and line. Line, sex, and pST dose effects (P< .05) were noted for most offal components and carcass components. Quantity of lean and bone in the ham was increased (P< .01) and that of fat decreased (P< .01) with dose of pST. Throughout the trial pST induced increases (P< .05) in serum concentrations of IGF-I, IGF-II, insulin, and glucose and decreases in urea nitrogen. Concentrations of pST 24 h after injection were lower (P< .05) in pST-injected pigs than in buffer-injected pigs, indicating negative feedback on endogenous pST secretion. The pST-induced increases (P< .05) in insulin, IGF-I, and IGF-II and the decrease in urea nitrogen were evident at 24 h after the initial injection. Although pST administration improved the growth performance and composition of lean and obese barrows and gilts, the influences of line and sex were not expunged by administration of pST.

Three generations of selection for 56-d blood cholesterol concentrations were used to establish low and high cholesterol lines of pigs in which cholesterol concentrations differed by 39% in the last generation. Litter size (number of fully formed pigs born per litter) diverged with each successive generation of selection and, at the third generation, litter size differed between the low and high line by two pigs (high line = 8.5 ± .6; low line = 10.5 ± .5; P <.05). A random selection of offspring (gilts, n = 109; boars, n = 46; barrows, n = 94) from the third generation and a control line maintained throughout the experiment were monitored for hormonal and anatomical relationships that might provide insight into the mechanisms that altered fecundity. Ovulation rate (number of corpora lutea) as determined on d 60 of pregnancy was increased in the low (n = 29) compared with the high cholesterol line (n = 38; 11.8 ± .3 vs 9.8 ± .3, respectively; P< .05), and litter size continued to be increased in the low cholesterol line (P< .05). No differences were noted between lines in kidney, ovarian, or total corpora lutea weight. Empty uterine weight and adrenal weight were increased in the high cholesterol line (P< .05) in randomly selected offspring of the third generation, and liver weight increased in the low line (P< .05). Associated with increased concentrations of cholesterol were increased serum concentrations of progesterone (gilts) and testosterone (boars) in the high cholesterol line (P< .05). (ABSTRACT TRUNCATED AT 250 WORDS)

Thirty-six female pigs selected for three generations for high (HS, n = 18) and low (LS, n = 18) serum cholesterol at 56 d of age were used to test the hypothesis that the two populations would respond differently to a high-fat, high-cholesterol diet (HD) and a low-fat, low-cholesterol diet (LD). The animals were four-way crosses (Chester White × Landrace × Large White × Yorkshire). All pigs were fed a standard corn-soybean meal starter diet from weaning (at 4 wk) to 8 wk of age and a grower diet from 8 to 12 wk of age. Initial serum total cholesterol concentration at 12 wk of age was higher (P< .05) in HS than in LS pigs (94.6 vs 76.9 mg/dL, respectively). The effect of genetic background persisted throughout the 13-wk experiment (25 wk of age); there was no interaction between diet and genetic background in serum total cholesterol (final concentrations were 114.3 mg/dL in HS-HD; 107.0 mg/dL in HS-LD; 105.9 mg/dL in LS-HD; and 89.7 mg/dL LS-LD). Trends over time revealed significant effects of diet (P< .01) and genetic background (P< .01) on serum total cholesterol. There was no effect of genetic background on high-density lipoprotein-cholesterol concentration; high-density lipoprotein-cholesterol as a percentage of serum total cholesterol was similar for all groups: 43% for HS-HD, 48% for HS-LD, 42% for LS-HD, and 45% for LS-LD.(ABSTRACT TRUNCATED AT 250 WORDS)

Pregnant Sprague-Dawley rats were used to determine the effects of the addition of 200 ppm of Cd (as CdCl2) to the diet factorially with two levels of dietary Ca (0.07% and 0.96%) on reproductive performance, concentrations of Cd, Cu, Fe, Zn, Ca and Mg in dam liver and kidney and in newborn progeny. High Cd significantly increased liver and kidney Cd, Zn and Ca and decreased liver Fe. High dietary Ca partially protected against accumulation of Cd in liver and kidney but had no effect on concentration of other elements. Number of live or stillborn pups per litter was not significantly affected by diet but high Cd significantly reduced pup birth weight. No grossly abnormal pups were noted. Concentration of Cd in bodies of newborn pups was increased approximately 8.6-fold by high Cd in the diet of dams fed the 0.07 % Ca-diet and 3.8-fold by high-Cd in the diet of dams fed the 0.96% Ca diet. Pup, Zn, Cu and Fe contents were significantly decreased and Ca was significantly increased by high-Cd in the maternal diet whereas pup Mg content was unchanged. Maternal Ca intake had no effect on concentration of Zn, Cu, Fe or Ca in newborn pups. The biological importance of the alteration in maternal and fetal tissue concentrations of Zn, Cu and Fe by high-Cd maternal diets is unknown.

Data on ewe body weights and on lamb birth and weaning weights and survival rates were recorded on a total of 557 multiparous Rambouillet, Hampshire × Suffolk and Synthetic I (composite of Finnish Landrace, Rambouillet and Polled Dorset) ewes in two experiments started after the first trimester of gestation. In Exp. 1, a 2 × 2 factorial arrangement of treatments included all combinations of low (.24% in gestation and .48% in lactation), or high (.80%) dietary Ca and low (20 ppm) or high (74 ppm) dietary Zn. No effect of dietary Ca or Zn level and no Ca × Zn interaction with respect to number of lambs born or weaned, birth weight, weaning weight or survival rate of the lambs or body weight of the ewes was shown. Mean number of lambs born was 1.63 ± .71 with a survival rate of 85.0 ± .3% and a weaning weight (59 d) of 19.4 ± 4.4 kg. Experiment 2 was a repeat of Exp. 1 except that two intramuscular injections of vitamins A, D and E (d 65 and 93 of experiment) were given to one-half of the ewes in each diet group. There was no effect of dietary Ca or Zn level or of vitamin administration on ewe body weight changes, number of lambs born (1.89 ± .55), survival rate (86.6 ± .3%), lamb birth weight (4.6 ± 1.5 kg) or lamb weaning weight (23.2 ± 7.2 kg). Blood plasma Ca, inorganic P and Mg concentrations of ewes in late pregnancy were unaffected by diet or vitamin injections. Plasma Zn was lower in ewes fed high Ca than in those fed low Ca diets, suggesting the possibility of lower absorption of dietary Zn by ewes fed high Ca. Overall, the data provide no evidence that current National Research Council recommendations for dietary Ca and Zn levels for pregnant and lactating ewes bearing 1.6 to 1.9 lambs are inadequate for maintenance of ewe body weight or have an adverse effect on lamb birth weight, weaning weight and survival.

Crossbred (Chester White × Landrace × Large White × Yorkshire) primiparous gilts were fed a standard gestation diet at 6,000 or 2,000 kcal calculated digestible energy (DE; 1.8 or .6 kg feed) daily for 84 or 108 (106 to 112) d after mating. Nonpregnant littermates were matched by body weight and assigned to the same diet treatments. Body weight and ultrasonic backfat measurements were made at 3-wk intervals. At 77 and 100 d, eight pregnant gilts (four control and four restricted) were fitted with indwelling jugular cannulas for frequent blood sampling (33 times over an 8-h period) to determine plasma glucose and growth hormone concentrations. At 84 and 108 d all gilts (eight pregnant and eight nonpregnant at d 84 and nine pregnant and nine nonpregnant at d 108 for each diet) were slaughtered and internal organs and reproductive tracts were removed and weighed. Fetal body and organ weights were recorded and an umbilical artery blood sample was removed from fetuses for plasma glucose, growth hormone, total protein and albumin measurements. The results demonstrated the ability of the primiparous gilt to maintain pregnancy through 106 to 112 d of gestation while consuming one-third (2,000 kcal DE daily) of recommended daily feed. Fetal weight at 84 and 108 d was reduced by about 13% without affecting litter size in gilts fed severely restricted intakes. Absolute and relative weights of maternal organs were affected by severe feed restriction, and backfat was reduced but there was no evidence of “pregnancy anabolism” in either adequately fed or restricted gilts. Fetal liver, kidney and gastrointestinal tract weights were reduced by maternal feed restriction; relative kidney weights were reduced while relative brain cortex weight was increased by maternal restriction. Maternal plasma glucose was unchanged by pregnancy or feed intake while plasma growth hormone peak amplitude, but not mean concentration or number of peaks, was increased by feed restriction. Fetal plasma glucose increased with time and in response to severe maternal feed restriction while plasma total protein and albumin decreased. Plasma growth hormone declined with time and was negatively correlated with fetal body weight.

Number of cellulolytic bacteria and their cellulase activity were determined from fecal samples of eight pairs of littermate pigs representing four litters (26 to 32 kg) fed a low or high fiber diet ad libitum (0 or 35% alfalfa meal, respectively) over a 70-d period. Fecal samples were obtained from all pigs on d 0, 5, 11, 18, 32, 53 and a final sample between d 67 to 70. Cecum and colon samples were obtained at slaughter. Growth and carcass data were also obtained during the study. Pigs fed the high fiber diet gained 17.3% less, had increased feed to gain ratio and less carcass weight at slaughter than those fed the low fiber diet (P<.05). Overall, a larger number of cellulolytic bacteria (P<.05) were found in the fecal samples from pigs fed the high fiber diet. The overall mean cellulolytic activity (mg glucose released•g dry weight fecal sample−1•30 min−1) was 27.7 compared with 33.8 (P<.05) for the pigs fed the low and high fiber diet, respectively. A lower concentration of organic acids (P<.05) was present in the fecal samples of the high fiber pigs. The overall mean acetate to propionate ratio was 1.92 and 2.48 (P<.01), and ammonia-N was 2.27 and .98 mg/g dry weight (P<.01) for the low and high fiber diet pigs, respectively. These data indicated that a 35% alfalfa meal diet significantly affects intestinal bacterial metabolism and number and activity of the cellulolytic population, along with performance and carcass characteristics.

Genetically obese and lean pigs were fed isonitrogenous-isoenergetic (digestible energy) amounts of a high or low fat diet from 25 kg body weight. Obese pigs gained less and required more feed per unit gain than lean pigs. Lean pigs were more muscular with less fat than obese pigs. Obese pigs utilized more dietary amino acids for energy (greater plasma urea N) than did lean pigs. Weight gain was similar at all intermediate periods in obese pigs fed the two diets. However, gain tended (P≤.10) to be greater and the ratio of dietary energy intake to gain tended (P≤.10) to be less in obese pigs fed high compared with low fat diets. Similar results were observed in lean pigs fed the two diets. The high fat diet produced more carcass adipose tissue deposition in both strains after 20 wk of feeding (detectable by ultrasound at 14, but not at 7 wk). Adipose tissue lipogenic rate (glucose incorporation) was similarly depressed by fat feeding in both obese and lean pigs. Obese and lean pigs both utilized dietary carbohydrate and fat differentially but there was no indication of genetic divergence regarding this utilization. In both strains of pigs, energy from the fat-enriched diet was preferentially partitioned into carcass adipose tissue.

One hundred and sixty Columbia- and Suffolk-cross intact male and female growing lambs (8 wk of age) were used in an 84-d feeding trial to determine the effect of two levels dietary Ca and Zn on weight gain, feed utilization and several blood and tissue traits. Two levels of Ca (.5 and .8%) and two levels of Zn (20 and 100 ppm) were fed in a 2 × 2 factorial arrangement of dietary treatments. There was no effect of diet on performance or on blood traits. Columbia lambs had heavier fleeces at slaughter than Suffolks (P<.01) and males had heavier fleeces than females (P<.01). Based on the similarity in performance among lambs fed the four diets differing in Ca and Zn level, it is concluded that a dietary Ca level of .5% and a Zn level of 19 to 26 ppm is adequate for normal weight gain, feed utilization, liver and humerus ash concentrations and blood plasma concentrations of Ca, P, Zn, total protein, albumin, alkaline phosphatase and blood hemoglobin and hematocrit. Further, it appears that an elevated level of dietary Ca does not precipitate a clinical Zn deficiency in the growing lamb, in contrast to the general observation in growing swine.

Two experiments were conducted, involving 68 third-litter sows and 20 first-litter gilts in Exp. 1 and 82 first-litter gilts in Exp. 2. On d 108 of gestation, the dams were moved into individual crates, stratified by parity and breed, and randomly assigned within strata, to one of two treatments: (1) fed a basal 16% protein corn-soybean meal diet, 1.8 and 2.7 kg once daily before farrowing and for the first 7 d of lactation, respectively, and then ad libitum until pigs were weaned at 28 d of age, and (2) fed the basal diet plus 1 g of L-ascorbic acid (vitamin C)/dam daily from d 108 of gestation through d 7 of lactation and on the same feeding schedule as for treatment 1. In Exp. 1, no effect of vitamin C supplementation was observed in sows or gilts on total pigs born/litter, number of live pigs/litter or average live pig weight at birth, 7 or 28 d of age, or on plasma vitamin C concentration of dams at d 108 of gestation or d 7 of lactation or of pigs at birth, 7 or 28 d of age. However, there was a lower (P<.01) plasma vitamin C concentration of the dams at d 7 of lactation than at d 108 of gestation. Plasma vitamin C concentration also declined (P<.01) as pigs aged. In Exp. 2, with all gilts, vitamin C supplementation again showed no effect on any of the reproductive traits measured in Exp. 1. It is concluded that daily supplementation of 1 g of vitamin C to either sows or gilts from d 108 of gestation through d 7 of lactation has no beneficial effect on the reproductive or lactation performance of swine.

Five sets of barrows from contemporary (C), genetically lean (L) and obese (O) phenotypes were used. The C pigs were crossbred Hampshire × Large White. The L and O pigs were crossbred Duroc × Yorkshire from lines selected for either low or high backfat thickness, respectively. The pigs were placed into adjustable cylindrical metabolism cages at 12 wk and again at 19 wk of age for 7-d adjustment and 4-d collection periods. Body weights of C, L and O pigs at 12-wk initial age were 32.9, 25.4 and 18.0 kg, respectively and at 19-wk initial age were 78.6, 55.0 and 39.7 kg, respectively. Pigs in each set consumed their daily feed allowance at the same percentage of their body weights and in two equal feedings. For 12-wk initial age period, daily weight gain (ADG) expressed as percentage of initial body weight was greater (P<.05) for C than for O pigs and was intermediate for L pigs. As determined by the total collection method, the percentage of retained nitrogen (RN) was similar (P>.05) for C and L pigs, but was less (P<.05) for O pigs. Coefficients of apparent metabolizable energy (ME) and N balance-corrected metabolizable energy (MEn) were similar (P>.05) among the three genotypes. The effect of genotypes on coefficients of RN, ME and MEn during the 19-wk initial age period showed the same trend as that during the 12-wk period. However, no difference was noted in ADG among the three genotypes. Apparent digestibilities of nitrogen (DN) and energy (DE) were also estimated by 4 N HCl-insoluble ash method. Genotype had no effect (P>.05) on coefficients of DN and DE for either the 12-wk or 19-wk period. Coefficients of DN and DE obtained by 4 N HCl-insoluble ash and total collection were similar (P>.05) at the 12-wk period, but were higher (P<.01) for the total collection method at the 19-wk period. It is concluded that the leaner C and L pigs retained more of ingested N, but that differences in weight gain and in energy and N retention among C, L and O pigs fed a standard grower diet are not related to digestibilities of dietary N and energy. Further, it is suggested that 4 N HCl-insoluble ash may be used as a natural indicator for estimating apparent nutrient digestibility in pigs, especially at younger ages.

Suffolk- and Columbia-sired crossbred Finn-sheep newborn lambs were used in four experiments to determine the effect of weaning to a dry diet at 10 d of age on survival, body weight gain and feed consumption to 42 d of age. Lambs used were originally members of triplet or quadruplet litters standardized to two lambs. All lambs were brought to the temperature-controlled lamb nursery at 1 or 2 d of age, given 50 ml bovine colostrum by stomach tube and trained during the first day to suckle from a nursing bottle containing a synthetic liquid milk replacer. Lambs were penned individually in .3 × 1.2 m raised wooden pens with expanded metal floors. At 2 or 3 d of age, lambs that had learned to use the nursing nipples were assigned sequentially to the experimental treatments. Body weight was recorded and liquid and dry feed intake were recorded for each lamb daily. Six of 34 lambs weaned to a dry diet at 10 d died of rumen impaction in Exp. 1 and 2. Initial body weights of survivors and nonsurvivors were similar in both experiments. Body weight and daily gain at 6 wk were similar for lambs reared conventionally on liquid-milk replacer (LMR) for 4 wk and for those weaned at 10 d to a dry pig starter diet (DPS). In Exp. 3, survival appeared to be improved by providing 118 ml of water twice daily by nipple for 3 wk to lambs weaned to a dry diet at 10 d. Among 16 lambs used in the experiment, 14 survived and neither of the deaths was due to rumen inpaction. In Exp. 3, only two of eight lambs weaned at 10 d to the regular dry lamb starter diet (DLS) survived; three DPS lambs and two DLS lambs died of rumen impaction. Daily weight gain and dry matter/gain from 0 to 6 wk of age were similar for LMR and DPS lambs in all four experiments. Overall survival was 85% for LMR lambs and 56% for DPS lambs (P<.05). Weaning lambs to a dry diet at 10 d may be a feasible management practice if the causes of rumen impaction that result in about 16% mortality can be identified and the syndrome prevented.

Nineteen Landrace sows mated to Landrace boars were randomly assigned, on d 91 of pregnancy, to three groups: (1) control (six sows)—fed standard 13% protein corn-soybean meal gestation diet at 1.82 kg/d to d 112 of pregnancy; (2) 4-d fast (seven sows)—fed standard gestation diet to d 94 of pregnancy, fasted from d 95 to 98 of pregnancy and then refed a semipurified fat-free diet ad libitum until d 112 of pregnancy, and (3) 8-d fast (six sows)—treated the same as group 2, except that the fast began on d 91 and extended through d 98 of pregnancy. The fat-free diet consisted of dextrose and soybean meal and was fortified with minerals and vitamins. On d 112 of pregnancy, all fetuses were removed by Caesar-ean section and determinations were made of fetal body and liver weights, fetal liver and gastrocnemius muscle glycogen concentrations, and maternal uterus and peritoneal adipose tissue glycogen levels. Sows in groups 2 and 3 consumed more (P<.01) average daily feed during the refeeding period than did the control sows. Fasting and refeeding failed to affect maternal or fetal tissue glycogen concentration, or fetal body or liver weight. Average sow tissue glycogen concentrations were .23 and 3.0 mg/g tissue for peritoneal adipose tissue and uterus, respectively. Average fetal liver and gastrocnemius muscle glycogen concentrations were, 87 and 62 mg/g tissue, respectively. Average fetal body and liver weights were 1,287 and 39.5 g/fetus, respectively. We conclude that fasting followed by refeeding of a fat-free diet to pregnant sows during late gestation does not increase maternal or fetal tissue glycogen content and appears to be of no value in enhancing pig survival in early postnatal life.

Cement kiln dust (CKD), samples of which have been reported to stimulate growth in cattle and sheep, was fed to weanling pigs in a 42-d experiment. CKD at levels of 1.5 and 3.0% was added to a corn-soybean meal-oats-whey-type diet containing inadequate amounts of Ca (.4% of the diet) to provide final dietary Ca levels of .85 and 1.3%. A diet containing 3% limestone (1.3% dietary Ca) served as a positive control. Body weight gain was depressed by 3.0% CKD, and histopathological lesions of the humerus, not typical of nutritional secondary hyperparathyroidism or rickets, were observed. The lesions detected were osteonecrosis, thinning of the cortex and reduction in the width of the epiphyseal cartilage. Width of the proximal epiphyseal plate and cortical index of the humerus (width of cortex divided by total diameter at narrowest point of diaphysis) were smaller in pigs fed 3% CKD than in pigs fed 3% limestone. CKD contained 2.3% Al, 15 ppm Cd and 110 ppm Pb, providing 690, .45 and 3.3 ppm of Al, Cd and Pb, respectively, in the diet containing 3% CKD. Kidney, liver and bone ash concentrations of these three minerals were not increased by CKD, and typical toxicity signs were absent. It is concluded that CKD may contain one or more factors that interfere with normal bone metabolism in growing pigs when the diet contains 3.0% CKD.

Twenty-four barrows from each of three genetic groups-lean (L), obese (O) and contemporary (C)-were assigned randomly within genetic group at 8 weeks of age to one of two corn-soybean meal-type diets (0 or 20% alfalfa meal) and fed ad libitumto slaughter at 96 kilograms. Body weight and feed consumption were recorded, and blood samples were collected at 4-week intervals for serum glucose, cholesterol and triglyceride determinations. Live backfat measurements were taken before slaughter, and carcass length and cross-sectional area of the longissimusmuscle were measured after slaughter. Weight of the empty stomach, small intestine, cecum and colon and length of the small intestine were recorded for all pigs. Alfalfa meal decreased daily body weight gain (P<.01) and increased feed to gain ratio (P<.01) in all genetic groups. Differences between genetic groups existed in backfat (0>L=C), carcass length and longissimusmuscle area (0

Production of volatile fatty acids (VFA) in the cecum and colon and their utilization as an energy source were studied in growing and finishing swine fed diets containing 0, 20, 40 or 60% alfalfa meal. The pH in the cecum and colon had an average value of 5.9, which supports fermentation of lumen contents. Increasing dietary fiber increased the concentration (mM/liter) of VFA in the large intestine; VFA ratio was changed in the cecum (increased acetic: propionic-butyric acids) but not in the colon. VFA disappearing from the lower gastrointestinal tract were equivalent to 79, 147, 227 and 155 kcal per day for pigs fed 0, 20, 40 and 60% alfalfa meal, respectively, at 48 kg body weight and 47, 231, 285 and 245 kcal per day, respectively, at 89 kg body weight. VFA produced in the large intestine can therefore provide up to 6.9, 11.3, 12.5 and 12.0% of the energy required for maintenance in the 48 kg pig and 4.8, 11.4, 14.0 and 12.0% in the 89 kg pig fed 0, 20, 40 and 60% alfalfa meal, respectively.

Yorkshire weanling barrows weighing an average of 17 kg were assigned in four groups of eight pigs in each of two replicates (64 pigs) to a completely randomized experiment in a 2 × 4 × 4 factorial arrangement (slaughtered at 48 or 89 kg; fed 0, 20, 40 or 60% alfalfa meal; slaughtered at 2, 4, 8 or 12 hr after the last feeding). A level of 20% alfalfa meal, resulting in a level of 26% cell wall in the diet, had no significant effect on daily gain and feed-to-gain ratio compared with a level of 0 alfalfa meal; 40 or 60% alfalfa meal significantly depressed daily gain and efficiency of feed utilization compared with 0 or 20%. Backfat thickness was inversely related to level of alfalfa meal in the diet; cross-sectional area of the longissimusmuscle was not affected by diet. Weight of the empty gastrointestinal tract (all segments except stomach) was increased with increasing fiber in the diet. Apparent digestibility of dry matter, cellulose, hemicellulose and nitrogen was progressively decreased with increasing fiber. Percentage of dry matter in digesta of all sections of the gastrointestinal tract was negatively correlated with cell wall content of diet and digesta. The lower dry matter of digesta of pigs fed high fiber was associated with a faster rate of passage and is suggested as being responsible for the lower digestibility of dry matter, nitrogen and cell wall components in pigs fed high fiber diets. Pigs slaughtered at 48 kg body weight had significantly higher apparent digestibility of dry matter, nitrogen and cell wall constituents than pigs slaughtered at 89 kg, probably due to the higher rate of passage of digesta in the heavier pigs. It is concluded that the depressing effect of fiber on apparent digestibility is due to the greater rate of passage of digesta in pigs fed high fiber and that there is no significant adaptation to high fiber diets with age during the growing-finishing period.

Methane generation has been proposed as a means of swine waste disposal. As a secondary treatment to recover nitrogen, carbon and other nutrients from the effluent of a methane generator, Arthrospira platensis(a blue-green alga also known as Spirulina) was grown and its nutritive value determined. This alga contained 55 to 61% crude protein and was easy to harvest. Three indoor culture ponds of .65 M2were designed and built. The ponds consisted of a bottomless wooden frame lined with a polyethylene sheet resting on a table top. Culture medium was kept circulating by a special aerator. An inorganic medium was evaluated. When algal growth reached a saturation point, there was still 70% of N03—and 11% of HCO3—left unused in the medium. Swine waste fermented at a hydraulic retention time of 10 days gave the highest ratio (2.3:1) of NH3-N to TKN (about 70% NH3-N). NH3seemed to support best the growth of algae, when the effluent was slowly infused. Organic acids in the effluent also provided a good source of carbon, a limiting factor when algae were intensively grown. Under the light intensity of 500 footcandles, Arthrospirayielded about 5 g/M2/day. A sample containing 2,038 mg of NH3-N produced 16,250 mg of dry algae, containing 9,750 mg protein or 1,560 mg N, giving an efficiency of nitrogen recovery of 76%. The protein of Arthrospira platensisshowed a PER of 2.25, apparent nitrogen digestibility of 76.7% and biological value of 67.7%; no toxic effects were noted.

Sixty-four mycoplasma pneumonia-free Yorkshire pigs weighing an average of 39 kg (two replicates of 32 each, weighing 35 and 42 kg, respectively) were randomly assigned within litter to four corn-soybean meal-type diet groups in a 2 × 2 factorial arrangement as follows: diet 1-Low Ca (.2%)-Low P (.4%); diet 2-High Ca (1.2%)-Low P; diet 3-Low Ca-High P (1.0%); diet 4-High Ca-High P. All diets met or exceeded N.R.C. recommended levels of all other nutrients. At a slaughter weight of approximately 100 kg, daily weight gain and feed/gain were calculated and right radius-ulna, liver and kidneys were removed for mineral analyses. There was no effect on weight gain or feed/gain or on bone, liver or kidney Mg, Cu, Mn or Zn concentration nor on percent Ca in bone ash. Pigs fed High Ca-High P had a significantly (P<.05) higher percentage of ash in the radius-ulna and a significantly lower concentration of Fe in the bone ash than pigs fed the other three diets. There were no cases of bone fracture and lameness was noted in only 2, 0, 1 and 0 pigs fed diets 1 through 4, respectively.It is concluded that the growing Yorkshire pig weighing more than 35 kg initially can adapt to dietary Ca and P levels and ratios considerably above or below N.R.C. recommendations with no detrimental effect on weight gain and no change in concentrations of Ca, Mg, Cu, Mn and Zn in bone ash or in liver and kidney, although it is generally recognized that a Ca:P ratio of less than 1:2 or greater than 2:1 results in abnormal bone.

Crossbred Duroc × Hampshire-Landrace (D × HL) pigs from 24 litters were assigned at 56 days of age to either a standard corn-soybean meal-type diet containing 16% protein or a similar diet containing 10% protein. Of 66 pigs fed 16% protein (53 females, 13 males), 13 females and three males were chosen at random after 42 days on test to constitute the control breeding population for the next generation. Of the 66 pigs fed 10% protein, the 13 females and three males with the highest body weight gain during 42-day test and the 13 females and three males with the lowest body weight gain were selected to constitute the selected breeding populations for the next generation. Each of the three breeding populations was mated at random within itself two times to obtain information on two parities for each parent population. All breeding groups were fed and housed similarly throughout the remainder of the life cycle. Progeny from the above matings were tested during a 42-day period beginning at 56 days of age. There were significant effects of treatment and of parity and there was a significant treatment × parity interaction. Multiple comparison of means indicated that control group progeny fed 16% protein did not gain faster (P>.05) than pigs fed 10% protein whose parents were selected for rapid weight gain on the low protein diet. Estimates of realized heritability were .11, .71 and .35 for first and second parity, and the weighted average of both parities, respectively. These estimates indicate that sufficient genetic variability exists for weight gain of pigs fed low protein diets to make selection worthwhile.

One hundred and twenty mycoplasma pneumonia-free Yorkshire weanling pigs were divided randomly at 4 to 6 weeks of age into two groups fed a high (1.2% Ca, 1.0% P) Ca-P or normal (.5% Ca., .4% P) Ca-P corn-soybean meal-type diet to slaughter at approximately 90 kg live weight to determine the effect of dietary Ca-P level on weight gain, feed utilization and mineral content of bone and liver. There was no significant effect of Ca-P level on weight gain, efficiency of feed utilization or on retention of Ca, Co, Cu, Mg, Mn or Zn in bone or liver. Fe content of radius-ulna was decreased (P<.05) by high Ca. Ash content of radius-ulna from pigs fed 1.2% Ca-1.0% P tended to be higher than that of radius-ulna from pigs fed .5% Ca-.4% P. The lack of change in bone and liver concentrations of Mg, Co, Cu, Mn or Zn of pigs fed high Ca-P diets suggests that major changes in body stores of required trace elements are not likely as a result of high-Ca-P feeding if dietary levels are at or above N.R.C. recommendations.

An experiment with 29 5-week-old Yorkshire pigs (initial weight 6.5 kg) was completed to study the effects of a fat-free diet on (1) growth rate, (2) body composition and (3) net synthesis of fatty acids.Semi-purified diets consisting principally of glucose and casein were used with or without supplementation of corn oil in a 28-day test. All pigs were caged in pairs in stainless steel metabolism cages and fed ad libitumin three replicates totalling 12 pigs per treatment. Five littermate controls were slaughtered at the beginning of the experiment to provide an estimate of the changes in body composition and net fatty acid synthesis.Weight gain was not significantly affected by the level of fat in the diet and no skin lesions or alopecia were seen in pigs fed the fat-free diet. Pigs fed the fat-free diet contained significantly less (P<.01) dry matter and ether extract than those fed the diet containing fat. The protein and ash percentages wefe similar for the two groups.

It was reported previously that selection for high (HG) or low (LG) plasma total cholesterol (TC) at 8 wk of age in a composite four-breed swine population resulted after four generations in divergent mean concentrations in the selected lines. The data revealed a significant positive correlation between body weight (BW) and TC concentration at 8 wk of age and differential responses in litter size, backfat depth, and carcass length at 6 mo of age. We report here the relationship between plasma TC concentration and other plasma traits related to growth and metabolism in the seventh generation of selection in these two lines of pigs. We measured plasma concentrations of TC, HDL cholesterol (HDL-C), triglycerides (TG), alkaline phosphatase (ALP), total protein (TP), albumin (ALB), urea nitrogen (urea N), and three transaminases (alanine aminotransferase, ALT; aspartate aminotransferase, AST; gamma glutamyltransferase, GGT) in seventh-generation male and female pigs at 8 wk of age. Birth weight (1.48 vs 1.38 kg), 8 wk BW (14.85 vs 12.00 kg), TC (116.8 vs 63.6 mg/dL), HDL-C (43.9 vs 25.5 mg/dL), TG (50.5 vs 33.0 mg/dL), and ALP (78.3 vs 44.9 units/L) were higher (P< .01) in HG than in LG pigs, whereas ALB (3.2 vs 3.4 g/dL), ALT (43.0 vs 45.9 units/L), and AST (53.0 vs 62.2 units/L) were lower in HG than in LG pigs (P< .05). At 8 wk, overall plasma TC concentration was correlated with BW (r = .34, P< .01) and with ALP (r = .23, P< .05) but was not related to ALT, AST, or GGT. Plasma TP urea N, and GGT were unaffected by genetic line on sex. We conclude that the difference between HG and LG pigs in TC concentration in generation 4 at 8 wk of age has persisted but not broadened in pigs of generation 7, that changes in plasma ALP, ALT, and AST may have occurred in response to selection for high or low plasma TC, and that ALP is correlated with plasma TC concentration.

Five sets of littermate gilts (8.2 ± .19 kg average initial weight) were randomly assigned within litter to a 16% protein corn-soybean meal basal diet (B), B + .308% neomycin, or B + 55 ppm carbadox. Each set was equally-fed individually once daily for 16 d in metabolism cages and 5 d in calorimeters. The average daily feed intake for 21 d was 276 g. Oxygen consumption and CO2production were measured during an 8- to 24-h postprandial period on d 16, 19, 20 and 21, and during a 32- to 48-h postprandial period after the d 21 feeding. Pigs were killed 50 h postprandially for gastrointestinal tract measurements. Dietary supplementation of antimicrobial agents (neomycin and carbadox) resulted in improvements (P<.01) in daily gain and efficiency of feed utilization and lower (P<.05) small intestinal mass in pigs. There was no difference (P>.05) in daily gain, feed efficiency or small intestinal mass between pigs fed neomycin- or carbadox-supplemented diets. Whole-animal fasting O2consumption and CO2production measured during the 8- to 24-h or 32-to 48-h postprandial period were not affected (P>.05) by the supplementation or the source of dietary antimicrobial agents. There were no differences (P>.05) in 8- to 24-h fasting O2and CO2measurements determined on d 16, 19, 20 and 21, indicating that adaptation to calorimeters was not needed by the pigs. The present study, thus, confirms that the growth-promoting effect of certain antimicrobial agents (e.g., carbadox, neomycin) in young pigs may be related to the reduction of the small intestinal mass, and that the hypothetic decrease in maintenance energy demand from reduced small intestinal mass cannot be detected consistently by measuring whole-animal fasting metabolic rate.

A 2 × 3 factorial arrangement was used in each of two trials with two levels of floor space allowance (.25, .13 m2/pig) and three dietary treatments (basal, basal + 660 ppm vitamin C, basal + 55 ppm carbadox). The reduction in floor space allowance was achieved in trial 1 by doubling the number of pigs/pen from eight to 16 and in trial 2 by reducing the size of pens by half. An 18% protein starter diet was used as the basal diet. Total numbers of pigs used were 216 in trial 1 and 144 in trial 2. Pigs were weaned between 4 and 5 wk of age (7.5 kg average wt) and fed ad libitum for 28 d. Reducing floor space allowance caused a (P<.05) reduction in weight gain of weanling pigs in both trials. When the reduction of floor space allowance was done by increasing number of pigs/pen (trial 1), pigs responded with a significantly reduced feed intake with no change in efficiency of feed utilization. However, when floor space allowance was reduced by changing the size of the pen (trial 2), feed intake of pigs was not affected but efficiency of feed utilization was reduced significantly. Neither form of crowding affected vitamin C concentration in adrenal glands and weights of adrenal glands, spleen and thymus. Dietary supplementation of carbadox, but not vitamin C, produced significantly greater weight gain, feed efficiency, and spleen weight of pigs in both trials. Although there was no interaction between crowding and dietary treatment in affecting the performance of pigs, supplemental carbadox improved the performance of crowding-stressed pigs by maintaining an adequate level of feed intake and improving feed efficiency, whether crowding was caused by increased pig density or by reduced pen size. No significant differences in phytohemagglutinin (PHA) skin test response or in the neutrophil-to-lymphocyte ratio (N/L) were observed among treatments in trial 1, while a significantly reduced response to PHA and a higher N/L were detected in crowding-stressed pigs in trial 2.

The β-adrenergic agonist, cimaterol, was fed to young growing pigs to determine whether the carcass compositional changes observed in finishing pigs fed a β-adrenergic agonist would be manifest in young animals. Furthermore, because cimaterol increased the deposition of lean mass in finishing pigs, it could have a protein sparing effect in young pigs that are rapidly accreting muscle mass and have a high dietary protein requirement. Pigs were fed cimaterol (at 0, .25 and .50 mg·kg−1diet) and either an adequate (18%) or restricted (14%) protein diet from about 10 to 60 kg body weight. Pigs that were fed the 14 compared with 18% protein diet grew slower and ate less but had the same gain-to-feed ratio. These pigs also had shorter carcasses, less lean muscle and more fat deposition (assessed by carcass measurements and carcass chemical composition) than pigs that received adequate protein. Plasma protein and albumin concentrations were greater and plasma cholesterol, triglyceride and fatty acid concentrations were lower in pigs fed high compared with low dietary protein. Dietary cimaterol had no effect on any of the growth or carcass variables or on adipose tissue metabolism. When fed the high protein diet, cimaterol-supplemented pigs had smaller livers and stomachs. Dietary cimaterol did not have any major detectable effects on these young pigs, nor was there any evidence for a protein sparing effect.

Pigs weighing 48 and 66 kg in Exp. 1 and 2, respectively, were fed a restricted amount of diet so that about 20% weight loss was incurred over a 3-wk period. During restriction, there was considerable loss of body fat in Exp. 1 as indicated by backfat depth, but in Exp. 2 there was little fat loss. There was loss of muscle mass and mass of several internal organs in Exp. 2 (not evaluated in Exp. 1). Beginning at 19 and 21 d in Exp. 1 (37 kg) and 2 (53 kg), respectively, pigs were refed ad libitum to 89 and 91 d, respectively. A comparable group of pigs was fed ad libitum from 1 d to 61 and 63 d, in Exp. 1 and 2, respectively. Refed pigs (RF) exhibited compensatory weight gain, but the rate was only slightly greater than that in pigs fed ad libitum (F). In Exp. 1, RF pigs ate considerably more than F pigs and were fatter, as indicated by ultrasonically determined backfat measurements. Comparative slaughter techniques were used in Exp. 2 so that estimates of muscle mass and internal organ weights could be obtained. In Exp. 2, RF pigs did not eat more than F pigs and were not fatter. The relatively small difference in starting weight and presumed subtle differences in body composition appear to have greatly influenced the physiological response to dietary restriction and subsequent refeeding so that differences in the composition of compensatory growth were observed in the two experiments.

Effects of diluting the energy content of a corn-soybean meal diet with either alfalfa meal or corn cobs on nutrient digestibility and rate of passage of feed residues and particle markers were measured in crossbred (Yorkshire × Landrace × Chester White × Large White) barrows with a mean body weight of about 80 kg. The excretion pattern in the feces of Cr-mordanted diet and of rare earths initially bound individually to the mixed diet or to the corn or soybean meal suggested a model having a single age-dependent compartment with time delay. The compartmental turnover rate parameter (λ1) estimated by this model did not differ for the rare earths individually used to mark the corn-soybean meal diet (Yb), the corn (La) or the soybean meal (Sm). In contrast, λ1for Cr was smaller (P<.001) than that of the mean for the three rare earths. The residence time due to displacement flow (τ) did not differ among markers. These results were interpreted to indicate that the high specific gravity of Cr-mordanted feed slowed flow due to mixing but not due to displacement. Correlations between λ1and τwere <.71. These results suggested that the flow of rare earths initially bound to feed ingredients provides a reasonable estimate of the flow of their undigested residues through the gastrointestinal tracts of nonruminant animals. Inclusion of the fibrous feeds reduced digestibility of dry matter, cell contents, crude protein and acid detergent lignin and increased digestibility of cell walls, cellulose and acid detergent fiber. Digestibilities of cellulose and acid detergent fiber were greater with alfalfa than with corn cobs as the fiber source. Differences in digestibility of crude protein and acid detergent fiber existed due to litter in one replicate of the experiment. Variation in digestibility was not significantly related to variation in λ1or τwithin or among treatments and litters. This suggests that variations in λ1and τ were not important causes of the observed variation in digestibility.

A 2 × 2 factorial arrangement with two genotypes of pigs (genetically obese and lean) and two dietary treatments (basal, a 16% protein corn-soybean meal standard grower diet, and basal + 220 ppm thyroprotein as iodinated casein) was used. The 28 gilts were housed individually and fed ad libitum from 121 d of age until slaughtered-at 99 kg body weight. Compared with lean pigs, genetically obese pigs had significantly lower average daily gain and gain/feed, greater backfat thickness, smaller loin eye area, shorter carcass length and lower circulating plasma triiodothyronine (T3) concentration. However, both total plasma and free thyroxine (T4) concentrations were similar comparing obese and lean pigs. Supplementation with thyroprotein increased circulating plasma concentration of both total and free T4and produced interactions with genotype in affecting daily gain and gain/feed of pigs. Thyroprotein reduced both daily gain and gain/feed in obese pigs, but increased daily gain and gain/feed in lean pigs. It is suggested, similar to the case with obese mice, that heat production of our genetically obese pigs may be more sensitive to thyroprotein administration compared with similar treatment of lean animals.

A 2 × 2 factorial arrangement with two levels (0, 660 ppm) of vitamin C and two levels (0, 55 ppm) of carbadox supplementation was used in two experiments with 112 crossbred pigs weaned between 4 and 5 wk of age. An 18% protein corn-soybean meal-oats-dried whey starter diet was used as the basal diet. Each diet was fed ad libitum for a 4-wk period to three replicates of four pigs in Exp. 1 and to four replicates of four pigs in Exp. 2. Vitamin C supplementation produced a significantly higher plasma vitamin C concentration in weanling pigs, but, contrary to results of our previous study, failed to improve average daily gain of the pigs. Daily gain was, however, improved significantly by carbadox supplementation. Carbadox also produced a significantly higher plasma vitamin C concentration in pigs after a 7-d lag period. Plasma Fe concentration of pigs was not affected by supplemental vitamin C, but was significantly higher in those fed carbadox-supplemented diets. Plasma ceruloplasmin concentration increased significantly in all treatment groups from the initial sampling period (d 0) to subsequent periods. No interactions between supplemental vitamin C and carbadox were observed in daily gain, feed efficiency and the measured plasma constituents.

Each of 64 pigs weaned between 4 and 5 weeks of age was fed ad libitumone of four diets: (1) a basal 18% crude protein, corn-soybean meal-oats-dried whey starter diet or (2,3,4) the basal diet supplemented with 330, 660 or 990 ppm L-ascorbic acid (vitamin C). The pigs were kept in groups of four and housed in an environmentally regulated nursery with a raised, expanded metal floor. The room temperature was maintained at 21 C and floor allowance was .54 m2/pig. After 28 days, dietary vitamin C supplementation had improved daily weight gain and daily feed intake of pigs without altering gain to feed ratio. Plasma vitamin C concentration decreased during the 4 weeks period after weaning in pigs not fed supplemental vitamin C but not in those fed supplemental vitamin C. Plasma Fe was reduced at day 28 in pigs given supplemental vitamin C. Simple correlation indicated a positive (P>.05) relationship between plasma vitamin C concentration and weight gain and a negative (P>.05) relationship between plasma vitamin C and plasma Fe concentration. Results obtained suggest that, under the experimental conditions, young pigs weaned between 4 and 5 weeks of age require dietary vitamin C supplementation for maximum weight gain and that the benefit of vitamin C addition may be related to Fe metabolism.

Twenty-one crossbred barrows (average weight 62 kg) were individually fed three diets for 42 days: (1) basal, 14% crude protein fortified corn-soy bean meal; (2) basal + 4% CaCl2· 2H2O + 2.22% Na5P3O10, and (3) diet (2) + 2.03% NaHC03. Diet 2 suppressed daily feed intake and reduced both weight gain and feed efficiency in pigs. It also caused an increase in plasma Cl concentration and a reduction in blood pH and concentrations of HCO3̄, total CO2and base excess. Feed intake and feed efficiency of pigs fed diet 3 were similar to those of pigs fed diet 1. Weight gain of pigs fed diet 3 was higher than that of pigs on diet 2 but lower than that of pigs fed diet 1. Diet 3 produced a higher plasma Cl concentration than diet 1 but a lower concentration than diet 2. However, blood pH and concentrations of HCO3̄, total CO2and base excess in pigs fed diet 3 were similar to those in pigs fed diet 1. It is concluded that ingestion of CaCl2increases plasma Cl concentration, which exceeds the bicarbonate buffering power capacity and produces a metabolic acidosis, thereby appearing to suppress appetite in pigs.

Eighty-eight multiparous sows of four breeds —British Landrace (BL), Chester White (CW), Large White (LW) and Yorkshire (Y)—were mated to boars of their own breed or another breed—BL, Hampshire (H) or Y—to form eight breed groups. All sows were fed daily 1.8 kg of a standard 14% protein gestation diet based on corn-soybean meal through day 100 of pregnancy (6,000 kcal digestible energy/day). From day 100 of gestation to parturition, each sow received either the basal diet (6,000 kcal digestible energy/day) or the basal diet plus 1.82 kg corn starch (12,000 kcal digestible energy/day). All sows were fed a 16% protein corn-soybean meal-based diet ad libitumfrom day 1 to day 28 of lactation. Energy intake during gestation had no effect on individual pig birth weight, percentage survival or 28-day body weight. There were differences among breeds in pig birth weight (P<.01) and 28-day weight (P<.01), and a breed X gestation energy level interaction (P<.05) was found, but the biological significance is questionable because of the small sample size. Pigs that nursed before blood samples were taken had lower (P<.01) hematocrit than pigs not allowed to nurse before blood sampling. Energy intake of the dam had no effect on the magnitude of the difference between nursed and nonnursed pigs. We conclude that the normal pregnant dam maintains blood glucose homeostasis during hyperalimentation, thereby rendering ineffective this approach to increasing neonatal growth and survival.

Two experiments were completed with a total of 54 5- to 7-week-old weanling Yorkshire pigs to determine (Experiment 1) the tissue retention of dietary selenium (Se) present in white sweet clover (Melilotus alba) relative to that provided as sodium selenite (Na2SeO3) and (Experiment 2) the tissue retention and liver distribution of Se present in fly ash incorporated into the diet.In Experiment 1, groups of four pigs each were randomly allotted to corn-soybean meal-type diets containing 5 or 10% white sweet clover grown either in low Se soil (.03 ppm Se in clover) or on fly ash (70 ppm Se in clover). Na2SeO3was added to the low Se clover diets to provide 0, 3.5 or 7.0 ppm of Se. Se concentrations of kidney, liver and skeletal muscle after 61 days were increased more by fly-ash grown sweet clover than by Na2SeO3, but blood Se was increased more by Na2SeO3. No histopathological lesions were found in liver, kidney, heart, pancreas or skeletal muscle. Diets had no effect on weight gain or feed to gain ratio.In Experiment 2, 30 pigs were fed from weaning to 92 kg slaughter weight on a corn soybean meal-type diet containing 0, 1, 2, 4 or 8% fly ash (5.7 ppm Se). Fly ash had no effect on weight gain and no histopathological lesions were found in heart, liver, kidney, pancreas or skeletal muscle. Tissue Se concentrations increased progressively with graded levels of fly ash in the diet. Distribution of Se in eight different sites in the liver was uniform. It is concluded that Se supplied in the diet as a component of fly ash or of white sweet clover grown on fly ash (probably as a constituent of seleno-amino acids) is absorbed and utilized for tissue deposition by the pig. The toxicological potency of clover-borne Se and its ability to alleviate vitamin E - Se deficiency signs relative to that of Na2SeO3remain unknown.

An experiment was conducted to determine if dietary zinc at 100 or 500 ppm and copper at 8 or 125 ppm would affect growth, tissue Cu and Zn or plasma and liver cholesterol.Yorkshire pigs 6 to 8 weeks old were fed a practical corn-soybean meal diet incorporating a 2× 2 factorial treatment arrangement of zinc and copper. The experiment began shortly after weaning and continued until the animals reached slaughter weight. Blood samples were obtained at 0, 2, 4, 8, 12 and 16 weeks (slaughter) of the experiment for determination of plasma Zn, Cu and cholesterol concentrations. Liver and kidneys were removed at slaughter for Zn, Cu and cholesterol (liver only) concentrations. Samples of several tissues were saved for histopathologic examination.Liver and kidney Zn and Cu concentrations reflected dietary Zn and Cu. Plasma Zn also reflected levels fed throughout the experimentalperiod. In contrast, plasma Cu was not altered by diet.Plasma cholesterol was significantly higher in animals fed the two high Zn diets after 4 weeks of treatment; however, Cu-supplemented animals manifested decreased plasma cholesterol compared to their respective Zn counterparts. Both effects dissipated with time. After 12 weeks of treatment, both a Cu× Zn and Zn× sex interaction were evident. There was no significant difference in liver cholesterol among dietary treatments and no evidence of tissue atherosclerotic lesions in any of the pigs. It is concluded that there is no evidence for a biologically significant influence of dietary Zn or Cu, at the levels used here, on plasma or liver cholesterol concentrations in the pig.

Thirty-two Yorkshire pigs (45 kg average initial weight) and 56 weanling Sprague-Dawley rats (45 g average initial weight) were used in a 2 × 2 × 2 factorial arrangement of treatments to determine the effect of dietary Ca, Cu and Zn levels on body weight gain and tissue mineral concentrations. Dietary levels of Ca were .06 and 1.4%, levels of Cu were 10 or 210 ppm and levels of Zn were 15 or 75 ppm in the eight diets. Pigs were removed individually from the experiment when body weight reached approximately 90 kg. Liver, kidney and radius-ulna were removed at slaughter and analyzed for Ca, Cu, Fe, Mg, Mn and Zn concentrations. Rats were slaughtered on day 28 of the experiment and liver, kidney and testes were removed for the same analyses. Daily gain of pigs was not significantly affected by diet, although three of 16 pigs fed low Ca had to be removed during the experiment due to bone fractures. Liver Cu was higher (P<.01) and liver Fe lower (P<.01) in pigs fed high Cu compared with low Cu diets. There was no effect of diet on kidney or radius-ulna mineral concentrations in pigs, except for a higher (P<.05) level of Zn in the radius-ulna ash of pigs fed high-Zn diets compared with low-Zn diets. Daily gain, feed intake and gain/feed of rats were higher (P<.01) with high Ca than with low Ca diets; there was no effect of dietary Cu or Zn level on daily gain, feed intake or gain/feed. High dietary Cu increased (P<.01) kidney Cu; kidney Cu was increased (P<.01) and Fe decreased (P<.01) by high Ca diets compared with low Ca diets. Kidney Mn was higher in rats fed high-Zn diets than in those fed low-Zn diets. There was a Ca × Cu interaction effect on kidney Mn whereby dietary Cu was associated with an increase (P<.01) in kidney Mn at the high dietary Ca level but not at the low level. Diet had no effect on kidney Zn nor on testes Ca, Cu, Fe, Mg or Zn concentration in rats. It is concluded that diets severely deficient in Ca can be tolerated by the finishing pig and growing rat without drastic effects on growth rate or net uptake of tissue Ca, Cu, Fe, Mg, Mn and Zn even in association with wide variations in diet Cu and Zn levels.

A method was developed to measure simultaneously the O2consumption (VO) by the whole animal and by the hepatic portal vein-drained organs (PVDO), including the gastrointestinal tract, spleen, and pancreas in conscious 3.5- to 4-month-old swine. The method was used to determine (i) the effect of feeding on hepatic portal vein blood flow rate (Qpv) and VO by PVDO and by the whole animal, and (ii) the significance of PVDO on the oxidative demand in the pig. Chronic cannulas were placed in the hepatic portal vein, carotid artery, and ileal vein. The Qpv was determined by an indicator dilution technique employing continuous constant infusion of 1% ρ-aminohippuric acid into the ileal vein. The VO2by PVDO was estimated by multiplying Qpv by arterial-portal vein O2difference measured with an arterial-venous O2difference analyzer connected to the carotid artery and portal vein cannulas. Whole animal VO2was measured with an open circuit indirect calorimeter. In seven pigs (3.5- to 4-month-old, 37.4 ± 0.8 kg) trained to be fed once daily, feeding (1.2 kg of feed mixed with 1.2 liter of H2O) caused postprandial (6 hr) Qpv to increase more than 34 ± 15% above the preprandial value of 34.5 ± 4.2 ml · min-1· kg-1body wt. The postprandial VO2by PVDO was elevated more than 46 ± 12% above the value of 1.52 ± 0.20 ml · min-1· kg-1body wt observed during the preprandial period. Whole animal VO2increased 45 ± 9 and 33 ± 7% above the preprandial value of 6.23 ± 0.57 ml · min-1· kg-1body wt for the first 6 hr and the 7 to 12 hr after feeding, respectively.

Sprague-Dawley growing rats were used in four experiments to determine the effect of a natural zeolite mineral, clinoptilolite, on portal blood ammonia concentration following oral administration of (NH4), CO4. Stomach tubing rats with 315, 472.5, 630, or 945 mg clinoptilolite/100 g body wt reduced portal vein blood ammonia concentrations of rats orally administered, simultaneously, 45 or 90 mg (NH4)2CO3/100 g body wt. The reduction was greater at the higher clinoptilolite concentration at each level of (NH4)CO3administration (i.e., 472.5 mg clinoptilolite was more effective than 315 mg at a dosage of 45 mg (NH4)2C03/100 mg body wt, and 945 mg clinoptilolite was more effective than 630 mg at a dosage of 90 mg (NH4)2CO3/100 mg body wt). Inclusion of 5% clinoptilolite in a diet containing 4% (NH4)2CO3did not decrease portal blood ammonia after a 30-min meal, but it did reduce portal blood ammonia concentration compared with that of rats fed the basal diet not containing clinoptilolite. It is concluded that clinoptilolite has the capacity to bind free ammonia in the gastrointestinal tract and that the degree of binding is predictable from its known ion-exchange capacity. The ammonia binding may be related to the improved efficiency of feed utilization reported in animals fed diets containing clinoptilolite.

A calcium-binding factor was detected in guinea pig intestinal mucosa. It was negatively charged and moved in an electrical field. Pronase quickly destroyed almost completely the calcium-binding activity although trypsin had practically no effect. The major calcium-binding peak was well defined. It was concluded that the factor is probably a protein. Calcium-binding protein was found throughout the gastrointestinal tract, with the calcium-binding activity decreasing with increasing distance from the stomach.The authors thank Dr. Walter L. Nelson for supplying the guinea pigs and Mr. Francis Davis and Mrs. Marie Brindak for their excellent technical assistance.

Plasma insulin, growth hormone, somatomedin, free and bound cortisol, and serum albumin were measured in human infants with protein-energy malnutrition and in age-matched control subjects. Insulin and somatomedin were reduced, growth hormone and free and total cortisol were elevated in malnourished infants. Free cortisol and somatomedin were negatively correlated (r= −0.78) and somatomedin and percentage weight deficit were negatively correlated in marasmus (r= −0.62) and kwashiorkor (r= −0.68). It is suggested that elevated plasma-free cortisol as well as depressed plasma insulin in protein-energy malnourished infants is partially responsible for the depressed plasma somatomedin and reduced protein synthesis and growth in children.

Twenty-four genetically obese and 24 lean barrows were allotted within genotype to either a 16% CP corn-soybean meal basal diet, the basal + .69 ppm cimaterol or the basal + 1.38 ppm cimaterol. Pigs had ad libitum access to their diets from 59.3 kg to 104.5 kg body weight. No genotype × cimaterol interactions were detected (P>.05). Neither genotype nor cimaterol supplementation had any effect (P> .05) on average daily weight gain or gain-to-feed ratio. Compared with lean pigs, obese pigs had higher fasting plasma urea nitrogen (BUN), a smaller gastrointestinal tract and a greater dressing percentage with a shorter and fatter carcass (P< .05). Cimaterol produced a higher fasting plasma BUN, a greater dressing percentage with a leaner carcass and a higher shear force value for loin chops (P< .05). Cimaterol also tended (P< .10) to increase heart weight. However, no difference was observed in these measurements between pigs fed .69 or 1.38 ppm cimaterol. In lean pigs fed the basal or .69 ppm cimaterol diet, there was no difference (P> .05) in the 8 to 24 h postprandial whole-animal heat production. Cimaterol effectively decreased fat deposition and increased lean accretion both in genetically obese and in lean pigs; there were no differential responses to cimaterol in pigs with different propensities to deposit body fat.

Twenty-four growing swine and 24 growing rats were fed high-protein (34%) diets on an ad libitum basis to determine their effects on body weight, carcass characteristics, intestinal microbiological profile and visceral organ weights. High dietary fiber reduced body weight gain and gain:feed ratio in both swine and rats and decreased body fatness in swine; it increased relative kidney weight (percentage of body weight) in both swine and rats and decreased relative liver weight in rats but increased it in swine. Absolute weights of stomach and large intestine were unaffected by high fiber in either species, but relative weight of small and large intestine was increased in swine and relative weight of stomach was increased in rats. High dietary protein increased absolute and relative weights of kidneys in both species and increased relative liver in swine but not in rats. Absolute weight of large intestine was increased by high dietary protein in rats and tended to be increased in swine; relative large intestine weight was increased in both species. The microbial profile of large intestinal contents of rats showed no effect of diet on Enterobacteriaceae, Campylobacter, Salmonella or total anaerobes and cellulolytic organisms, but coliforms were higher in rats fed high fiber or high protein than in controls. We conclude that dietary levels of fiber and protein influence growth of specific segments of the gastrointestinal tract of growing rats and swine, probably by different mechanisms of action.