J. T. Yen

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.

Thermal Environment Effects on Growing-Finishing Swine Part I—Growth, Feed Intake and Heat Production

ABSTRACT SIXTY crossbred gilts were reared two per pen in five pens each at environmental temperatures of 5, 10, 15, 20, 25 and 30°C. Animals initially weighed an average of 43.6 kg and were slaughtered at an average weight of 86.7 kg. Statistically, growth rate was unaffected by temperature from 5 to 20°C. However, there was a trend toward decreased growth rate from 20 to 5°C and substantial decreases above 20°C. Feed intake decreased as temperature increased from 5 to 30°C and was related to temperature by a polynominal function. Heat production per unit weight decreased with increasing temperature and increased with increasing feed intake and body weight. The heat production data were fitted to a multiple linear regression equation. Conversion of feed to gain was most efficient at 20 and 25°C. The data define a broad range of acceptable thermal conditions rather than a singluar optimal environmental temperature.

Impact of dried skim milk in production diets on Lactobacillus and pathogenic bacterial shedding in growing-finishing swine.

Aims:  To determine the possible effects of inclusion of dried skim milk (DSM) in swine diets on indigenous Lactobacillus spp. and Escherichia coli, and its potential for controlling pathogen shedding and affect animal growth in growing‐finishing swine.

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.

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.

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.

Chapter 4: Measuring Energetics of Biological Processes

[First paragraphs]: Measurement of the energetics of biological processes is the key component in understanding the thermodynamic responses of homoeothermic animals to their environments. For these animals to achieve body temperature control, they must adapt to thermal-environmental conditions and variations caused by weather (the meteorological condition of a region), climate, vegetation, topography, and shelters (see Figures 2 and 3 of Chapter 1). Adaptation can take different forms as defined by Hafez (1968). Physiological adaptation is the capacity and process of adjustment of the animal to itself, to other living material, and to its external physical environment. Genetic adaptation refers to the selection and heritability of characteristics for a particular environment or climatic region. A long-term adaptive physiological adjustment is referred to as acclimatization. We know this occurs through observations of animal conformation, animal types, respiratory rate, color, behavior, food selection, etc. Since adaptation of the animal to its thermal environment requires regulation of body temperature, measurement of that adaptation through animal energetics provides an indicator of the extent and energetic cost of adaptation.

Chapter 3: Energetics of Biological Processes

[First paragraphs]: All systems, even biological systems, must obey physical laws. Thus, the energetics of biological processes must obey the laws of thermodynamics, which describe the conversion of energy from one form to another. Therefore, it is important to review these principles and how they relate to biological systems and the energy balance in livestock. This includes the distribution of energy from feed, the transfer of energy to and from the environment, and how livestock uses the energy.

Body Weight Deficit in the Absence of Reduction in Cerebrum Weight and Nucleic Acid Content in Progeny of Swine Restricted in Protein Intake during Pregnancy

Abstract 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 (<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 <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.