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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.

High iron consumption has been proposed to relate to an increase in the risk of colon cancer, whereas high levels of supplemental sodium phytate effectively reduce iron-induced oxidative injury and reverse iron-dependent augmentation of colorectal tumorigenesis. However, the protective role of intrinsic dietary phytate has not been determined. In this study, we examined the impact of removing phytate present in a corn-soy diet by supplemental microbial phytase on susceptibility of pigs to the oxidative stress caused by a moderately high dietary iron intake. Thirty-two weanling pigs were fed the corn-soy diets containing two levels of iron (as ferrous sulfate, 80 or 750 mg/kg diet) and microbial phytase (as Natuphos, BASF, Mt. Olive, NJ, 0 or 1200 units/kg). Pigs fed the phytase-supplemented diets did not receive any inorganic phosphorus to ensure adequate degradation of phytate. After 4 months of feeding, liver, colon, and colon mucosal scrapings were collected from four pigs in each of the four dietary groups. Colonic lipid peroxidation, measured as thiobarbituric acid reacting substances (TBARS), was increased by both the high iron (P< 0.0008) and phytase (P< 0.04) supplementation. Both TBARS and F2-isoprostanes, an in vivo marker of lipid peroxidation, in colonic mucosa were affected by dietary levels of iron (P< 0.03). Mean hepatic TBARS in pigs fed the phytase-supplemented, high iron diet was 43%-65% higher than that of other groups although the differences were nonsignificant. Moderately high dietary iron induced hepatic glutathione peroxidase activity (P= 0.06) and protein expression, but decreased catalase (P< 0.05) in the colonic mucosa. In conclusion, intrinsic phytate in corn and soy was protective against lipid peroxidation in the colon associated with a moderately high level of dietary iron.

Crossbred pigs were selected for high (HTC) or low (LTC) plasma total cholesterol (TC). Pigs from the seventh (n = 51) and eighth (n = 92) generations were used to determine restriction fragment length polymorphisms (RFLP). Using TaqI restriction enzyme digestion, the frequencies of two alleles (2.8- or 5.0-kb fragments) of the cholesterol 7 alpha-hydroxylase (CYP7) gene were determined in the two populations as a potential indicator of TC concentration at 8 weeks of age. Only the 2.8-kb fragment allele was present in the 26 HTC pigs tested in Generation 7. In the LTC pigs both the 2.8- and 5.0-kb alleles were present in 12 pigs, and only the 5.0-kb allele was present in 13 pigs. The allele frequencies of the 2.8 and 5.0 fragments, respectively, were .26 and .74 in LTC pigs and 1.00 and 0 in HTC pigs. There was an association (P < .001) between the 5.0- and 2.8-kb CYP7 alleles, respectively, and low and high TC concentrations. In Generation 8, all HTC pigs were homozygous for the 2.8-kb allele. The 5.0 kb allele was present in all LTC pigs tested and was homozygous in 57% of LTC pigs. Mean plasma TC was 105.0 mg/dl in 30 pigs homozygous for the 2.8-kb allele in Generation 8; means for LTC pigs were 53.5 and 60.4 mg/dl in 35 pigs homozygous for the 5.0-kb allele and in 27 heterozygous pigs, respectively. High TC was associated with the presence of the 2.8-kb allele, and low TC was associated with the presence of the 5.0-kb allele in both Generations 7 and 8. We conclude that TaqI RFLP analysis of the CYP7 gene is a reliable indicator for TC in these swine.

Increased visceral organ mass raises the energy cost of maintenance in animals. To determine the nutritional factors that affect organ size during growth and development, we studied 12 genetically obese 4-week-old pigs for 14 days. The piglets had free access to either a control (17% protein) or a high protein (34%) diet. They were sacrificed after 14 days and their empty gastrointestinal tracts, livers, and kidneys were weighed and samples were analyzed for protein and DNA concentrations. The absolute and relative (percentage of body weight) weights of liver and kidneys were greater in high protein than control piglets: liver (313 vs 246 g, SD = 24, P < 0.09; 3.61% vs 3.18%, SD = 0.04, P < 0.01); kidneys (57 vs 41 g, SD = 4, P < 0.04; 0.66% vs 0.55%, SD = 0.02, P < 0.01). Protein content was greater in high protein than control pigs in both liver (48.2 vs 34.0 g, SD = 3.4, P < 0.03) and kidneys (6.0 vs 4.6 g, SD = 0.5, P < 0.06). Liver and kidney total DNA were unaffected by diet in both groups. The protein to DNA ratio was greater in high protein than control pigs in both liver (45.4 vs 39.0, SD = 0.6, P < 0.01) and kidneys (26.6 vs 24.9, SD = 0.4, P < 0.02). We conclude that when weaned pigs have free access to a high protein diet (2 x requirement) for 2 weeks, liver and kidney protein accretion increases, suggesting cell hypertrophy, with no clear evidence of cell hyperplasia.

Twenty-six 3-week-old genetically obese pigs were fed in two experiments to determine the serum chemistry profile during severe protein malnutrition and repletion. Severe protein deficiency was produced in pigs fed the high-fat, low-protein diet (growth failure, rough hair, low serum total protein and albumin). In Experiment 1, blood was sampled from the anterior vena cava of each pig five times during depletion and three times during repletion to determine serum total cholesterol, high density lipoprotein (HDL)-cholesterol, triglycerides, total protein, albumin, glucose, Ca, inorganic P, Mg, Na, K, Cl, total bilirubin, urea N, creatinine, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase. In Experiment 2, blood was sampled weekly for 8 weeks for serum total cholesterol, HDL-cholesterol, triglycerides, albumin, glucose, Ca, P, Mg and alkaline phosphatase. HDL-cholesterol was increased (P less than 0.01) and albumin was decreased (P less than 0.01) in protein-deficient pigs in both experiments. Creatinine, total bilirubin, gamma-glutamyltransferase, alanine aminotransferase, and aspartate aminotransferase were elevated in protein-deficient pigs compared with controls after 7 weeks of depletion. Inorganic P (P less than 0.01), Ca (P less than 0.01), and Mg (P less than 0.05) concentrations were depressed in protein-depleted pigs compared with controls in both experiments. After 8 weeks of repletion in Experiment 1, all elements except inorganic P were similar in the two groups. Short-term, severe, protein malnutrition affected lipid, electrolyte, and structural mineral metabolism and indices of liver function in the absence of parasites, diarrhea, and infection. The effects were reversed after 8 weeks of repletion. We conclude that the elevated serum cholesterol in protein deficiency is related primarily to an increase in the HDL fraction.

Crossbred (Chester White x Landrace x Large White x Yorkshire) primiparous gilts were fed daily a corn-soybean meal-based gestation diet at 1.8 kg (C) or 0.6 kg (R) (6000 or 2000 kcal calculated digestible energy, DE) or a high-protein diet (RCal) at 0.6 kg (2000 kcal calculated DE) from day of mating to slaughter at 100 to 106 days of gestation. The RCal diet contained three times the concentrations of protein and of mineral and vitamin supplement present in the C diet. Body weight and ultrasonically estimated backfat depth were recorded at 0, 4, 8, and 12 weeks postcoitum. The results showed differential effects of form of diet restriction (R vs RCal) on body weight, backfat depth, relative and absolute uterine weight, and on relative kidney, stomach, and trimmed wholesale cut weights of the dam. Maternal and fetal plasma glucose and urea-N concentrations were higher in RCal than in R groups. Total uterus plus gastrointestinal tract relative weight, with or without fetuses, was lower in RCal than in R and C gilts. The ratio of uterus (with or without fetuses) weight to gastrointestinal tract weight was greater in R than in C or RCal gilts. The data are interpreted to indicate that restriction of carbohydrate-fat calories only compared with restriction of a standard diet throughout gestation in swine had a negative effect on uterine growth associated with repartitioning of nutrients to visceral organ and lean tissue growth at the expense of maternal uterine tissue and body fat conservation.

Fifty-six castrated male progeny of crossbred (Chester White x Landrace x Large White x Yorkshire) dams fed an adequate diet (control, C), a control diet fed at one-third of C (restricted, R), or diets severely deficient in protein (PF) or restricted in nonprotein calories (RCal) were killed at age 25 weeks. Dams were fed their respective diets in the following regimens: C, 1.8 kg (6000 kcal daily) throughout pregnancy; R, 0.6 kg of C diet daily for 70 days, then 1.8 kg of C daily to parturition at about 114 days; PF, 1.8 kg of a "protein-free" diet (less than 0.2% protein) throughout pregnancy; RCal, 0.6 kg daily (2000 kcal) of a diet containing three times the concentration of protein, minerals, and vitamins provided by the C diet for 70 days, then 1.8 kg of C daily to parturition. All dams were fed an adequate diet ad libitum through a 28-day lactation. Castrated male progeny were assigned to one of two replicates based on birth date and fed a corn-soybean meal diet ad libitum from weaning to age 25 weeks, supplemented from age 10 to 12 weeks with 0, 110, or 220 mg/kg of thyroprotein (iodinated casein). Cerebrum weight was unaffected by maternal diet, despite a significant (P less than 0.001) reduction in body weight of progeny of PF dams compared with other groups, resulting in a higher relative cerebrum weight in progeny of PF dams than in progeny of C, R, and RCal dams. Absolute and relative weights of RNA, DNA, and total protein in cerebrum were unaffected by maternal diet. Thyroprotein supplementation to the diet of the progeny had no effect on cerebrum weight or its protein or nucleic acid content. It is concluded that maternal protein deprivation but not restriction of feed or nonprotein calorie intake to one-third of recommended allowance during gestation results in stunting of body weight in young adult progeny but does not affect cerebrum weight, cerebrum cell number (DNA), or protein synthetic activity (RNA), or RNA-to-protein ratio.

Weanling Landrace X Yorkshire swine were fed a basal diet or a diet containing 3% clinoptilolite (a natural zeolite) with or without 150 ppm CdCl2 or 3% zeolite NaA (a synthetic zeolite) with or without 150 ppm CdCl2 for 31 days. Hematocrit and hemoglobin were depressed significantly in animals fed Cd in the absence of zeolites, but not in their presence. Liver Cd concentration was increased dramatically by added dietary Cd but was significantly lower in animals fed clinoptilolite with Cd than in those fed Cd alone (11.4 vs 16.5 ppm). Liver Fe and Zn were decreased by dietary Cd; liver Fe was not affected significantly by clinoptilolite or zeolite NaA, but liver Zn was increased by zeolite NaA. Kidney dry matter, Zn, and Cd concentrations were increased by dietary Cd; neither clinoptilolite nor zeolite NaA affected kidney Cd concentration. Zeolite NaA increased kidney dry matter both in the presence and in the absence of dietary Cd. Plasma urea-N, K, Na, and Mg were unaffected by Cd or by either zeolite. The data illustrate the different effects of dietary clinoptilolite compared with zeolite NaA on blood plasma, liver, and kidney concentrations of minerals and provide evidence that both zeolites offer some protection against Cd-induced Fe-deficiency anemia; the magnitude of this protection and the effects of each zeolite on tissue concentrations of Cd and other materials need further quantification.

Thirty-two genetically lean and obese Yorkshire X Duroc crossbred castrated male pigs were divided within genetic line into two groups at 7 weeks of age. Eight pigs within each line were fed a diet low in fat and cholesterol (maize-soybean meal diet fortified with minerals and vitamins). The other group was fed a similar diet containing added beef tallow (11%) and dried egg yolk (1%). All pigs were fed ad libitum for 4 months when one-half of each group was slaughtered. All other pigs were continued on their respective diets at a restricted level of intake for an additional 5 months at which time the protein source of two pigs in each diet group within each genetic line was changed from soybean meal to casein. After an additional 6 months on their respective diets (16 months total duration of experiment) these pigs were slaughtered. Blood samples were taken monthly or bimonthly for total plasma cholesterol and triglycerides. At slaughter, the aorta was opened, stained with Sudan IV, and the stained area traced and measured planimetrically. Only a moderate rise occurred in plasma cholesterol and triglycerides of pigs fed high fat-high cholesterol diets. Genetically obese pigs were no more susceptible to diet-induced hypercholesterolemia and to the percentage of the surface area of the aorta stained with Sudan IV than were lean pigs. It is concluded that obesity per se is not necessarily associated with development of atherosclerosis in pigs and that innate ability to metabolize high dietary cholesterol is of greater importance than body fatness in determining the response to diet.

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 concentration of Zn, Cu and Fe by high-Cd maternal diets is unknown.

Three-hundred and eighteen female swine representing contemporary commercial swine breeds (34 Chester White, 43 Large White, 42 Landrace, 40 Yorkshire, and 159 four-breed crossbreeds) were used to evaluate genetic variation between and within breeds for levels of plasma cholesterol and plasma triglycerides. Blood was sampled from all pigs after a 16-hr fast at 154 days of age. Plasma cholesterol was measured in all pigs and triglycerides were measured in 232 pigs. Paternal half-sib heritabilities (h2) for plasma cholesterol and plasma triglycerides were 0.45 +/- 0.23 and 1.04 +/- 0.32, respectively. Breed differences were not apparent for either trait. Phenotypic and paternal half-sib genetic correlations between the two traits were 0.16 and 0.66, respectively. Neither body weight nor backfat depth were important in affecting the estimate of h2 for either trait. The relatively high h2 of total plasma cholesterol and of total triglycerides offers the possibility of developing, through selection, populations of hypercholesterolemic or hypertriglyceridemic swine useful as models for studies directed toward further understanding of human cardiovascular disease.

A method was developed to measure simultaneously the O2 consumption (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% p-aminohippuric acid into the ileal vein. The VO2 by PVDO was estimated by multiplying Qpv by arterial-portal vein O2 difference measured with an arterial-venous O2 difference analyzer connected to the carotid artery and portal vein cannulas. Whole animal VO2 was 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-1 body wt. The postprandial VO2 by PVDO was elevated more than 46 +/- 12% above the value of 1.52 +/- 0.20 ml.min-1.kg-1 body wt observed during the preprandial period. Whole animal VO2 increased 45 +/- 9 and 33 +/- 7% above the preprandial value of 6.23 +/- 0.57 ml.min-1.kg-1 body wt for the first 6 hr and the 7 to 12 hr after feeding, respectively. Although PVDO represent only 5% of body weight, they used 25% of whole body VO2. The study clearly illustrates the significance of PVDO on the whole animal oxidative demand in conscious growing swine.