Wilson G. Pond

Oxygen Consumption by Portal Vein-Drained Organs and by Whole Animal in Conscious Growing Swine

Abstract 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% ρ-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.

Heritability of Plasma Cholesterol and Triglyceride Concentrations in Swine

Abstract 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 (h 2) 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 h 2 for either trait. The relatively high h 2 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.

Protection by Clinoptilolite or Zeolite NaA against Cadmium-Induced Anemia in Growing Swine

Abstract 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 animls 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.

Effect of Obesity per se on Plasma Lipid and Aortic Responses to Diet in Swine

Abstract 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.

Porcine adrenal prolactin receptors: characterization, changes during neonatal development and effects of hypoprolactinemia.

1. Adrenal prolactin (PRL) receptors were identified within the adrenal cortex of pigs (Sus domesticus), and found to be located specifically on isolated zona fasciculata/reticularis cells (6437 sites per cell). 2. These PRL receptors were associated with binding to [125I]-oPRL which was characterized as being time and temperature dependent, specific for PRL, saturable, of high affinity (Ka = 10(10)/M) with a single class of binding sites, and irreversible except under extreme conditions. 3. The concentrations (fmol/mg protein) of PRL receptors decreased by 35% (P less than 0.05) between 3 and 10 days of age, and subsequently remained constant until 30 days of age. Total content (fmol/paired adrenals) increased progressively (2-fold, P less than 0.05) between 3 and 30 days of age. 4. Short-term (less than 16 hr) and prolonged (7 weeks) hypoprolactinemia (46-64% of control levels, P less than 0.05) were not associated with changes in numbers of porcine adrenal unoccupied PRL receptors.

Decreased Absorption of Orally Administered Ammonia by Clinoptilolite in Rats

Abstract 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)CO3 administration (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)2CO3 did 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.

Nutritive value of Nigerian rubber seed (Hevea brasiliensis) meal and oil. III. Performance characteristics, relative organ weights, hematocrit and plasma metabolites of growing female rats fed corn diets containing rubber seed meal, soya bean meal or casein

Abstract Growing Sprague-Dawley female rats were used to compare the effects of feeding corn diets containing rubber-seed meal (RSM), soya bean meal (SBM) or casein (CA) on their performance characteristics, relative organ weights, hematocrit and some plasma metabolites in a 21-day experiment. The 30 rats used were randomly divided into 5 equal treatment groups of 6 rats, kept in individual cages and fed 5 different 12% protein isocaloric diets consisting of corn plus (1) RSM, (2) RSM + lysine + methionine, (3) SBM 1, (4) SBM 2, and (5) casein + methionine. All diets supplied equal proportions of protein from corn and protein sources (6.7:5.3, corn:protein source) except Diet 4 which had a ratio of 7.5:4.5. Rats fed RSM Diet 1 had significantly lower daily gains (ADG), higher feed:gain ratios, and lower relative liver weights, total plasma protein, plasma albumin, and protein efficiency ratios (PER) than the rats fed all the other diets ( P P > 0.05) for HCT, plasma urea N or cholesterol. The diet which contained casein plus 0.2% DL methionine did not significantly improve any of the traits measured as compared with SBM diets, but it did significantly improve the total plasma protein and reduced liver weight relative to Diet 1. It is concluded that growth performance of rats fed a corn-RSM diet is inferior to that of rats fed a corn-SBM diet and that supplemental methionine and lysine in RSM diets promoted performance similar to that obtained with SBM.

Nutritive value of Nigerian rubber seed (Hevea brasiliensis) meal and oil. IV. Effects of graded levels of rubber seed meal and oil on energy and nitrogen utilization by growing rats

Abstract Two experiments were conducted to determine the effects of graded levels of rubber seed meal (RBSM) and rubber seed oil (RBSO) on energy, dry matter and nitrogen (N) digestibility, and N retention of growing rats. In the first experiment, RBSM replaced 25, 50, 75 and 100% of the protein contributed by the soya-bean meal (SBM) in the control diet. The 100% RBSM substitution was either unsupplemented or supplemented with amounts of dl -methionine and l -lysine calculated to make up their concentrations to the minimum recommended National Research Council levels. In the second experiment, maize oil (MO) and RBSO replaced maize starch at 3, 6 and 9% in a 2 × 3 factorial arrangement of treatments. The diets in both experiments were iso-nitrogenous, containing 17% (Experiment 1) and 15% (Experiment 2) crude protein on a fresh weight basis. In Experiment 1, significant reductions were obtained in dry matter, energy and N digestibility, in absolute N retention and in the percentage of digested N retained ( P

Maternal tissue repartitioning in pregnant primiparous swine in response to restriction of calories or feed

Abstract 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.

SUBSEQUENT RESPONSE TO EARLY DIET CHOLESTEROL AND FEED RESTRICTION IN SWINE

Abstract Three four-way cross (Chester White × Landrace × Large White × Yorkshire) female pigs from each of twelve litters were used. One pig from each trio remained with its primiparous dam and its other littermates to age 28 d. Two pigs from each trio were removed to individual boxes at age 24 to 36 h and fed liquid sow-milk substitute containing low cholesterol (14 mg/100 g) or high cholesterol (151 mg/100 g) to age 28 d. All pigs were weaned to a dry diet containing 182 mg cholesterol/100 g to age 12 wk and 115 mg cholesterol/100 g from age 12 wk to 20 wk. Carcass measurements and organ weights were recorded at slaughter (20 wk) and liver was analyzed for cholesterol. Body weights were recorded weekly to 28 d and bi-weekly thereafter; serum total cholesterol was determined on d 1, 28, 56, 84, 112 and 136. Sow-reared (SR) pigs were heavier (P