Dietary Niacin Needs of High Lean Pigs

Pigs of a high lean strain reared via an SEW scheme were self-fed a basal diet supplemented with 0, 15, or 30 mg niacin/kg diet from 10 to 27 kg body weight. The basal diet contained 18 mg of total niacin and 9.4 mg of bioavailable niacin per kg diet. Dietary niacin supplementation did not alter pig growth, efficiency of feed utilization, or body nutrient (protein, fat) accretion. Based on these results, dietary niacin needs of high lean, high health pigs are not greater than current NRC (1998) estimated requirements

Pantothenic Acid Needs for Specific Biological Processes in Pigs

Two lean growth strains of pigs and three dietary concentrations of bioavailable pantothenic acid [32, 132, 262% of the estimated NRC (5) requirements for 5 to 10 kg pigs] were utilized to determine the pantothenic acid needs for specific biological processes in the pig. Endogenous pantothenic acid production was estimated as 2.96 and 2.73 mg/BW kg.75/d for the high and moderate lean strains. Based on dietary as well as endogenously synthesized pantothenic acid supplies, the gross efficiency of total pantothenic acid utilization was estimated as 10.5 % and was independent of dietary pantothenic acid concentration. Dietary pantothenic acid additions did not alter bodyweight gain or body energy retention. However, dietary pantothenic acid additions did alter body composition by redirecting energy from body fat accretion toward the more economically valuable process of protein accretion. Based on these data, pantothenic acid in amounts above that needed to support body energy accretion has a biological role in regulating body composition

The Digestiblity of Phosphorus in Dicalcium Phosphate in Pigs

The digestibiltiy of P in dicalcium phosphate, a P source considered to have a high relative bioavailability , was determined to be 68.1 % in pigs. The digestibility of the phosphorus was not altered by dietary calcium/available P ratio or stage of pig growth (10 vs 30 kg body weight).These data highlight the opportunity/incentive for technologies aimed at improving P digestibility in P sources (inorganic P sources) with high relative phosphorus bioavailabilities

Dietary Folic Acid Needs of High Lean Growth Pigs

Twelve sets of five littermate barrows were utilized to determine the folic acid needs of a high lean genetic strain of pigs experiencing a low level of immune system activation. Pigs were penned individually and given ad libitum access to a corn, soybean meal, 27% milk product diet containing dietary concentrations of folic acid equivalent to 100, 200, 300, 400, and 500% of the current NRC (2) estimated requirement for 11 to 22 lb pigs. Pigs were started on test when the average litter weight reached 19 pounds and were taken off test as individual pigs reached a body weight of 51 pounds. Dietary folic acid concentration did not alter daily body weight gain, daily feed intake, feed:gain ratio, or rates of body protein and fat accretion. Based on these data, a dietary folic acid concentration of 0.14 mg per pound of feed is adequate to support optimal growth and body nutrient accretion in high lean growth pigs fed corn-soybean meal-milk product diets from 19 to 51 pounds

Role of Pantothenic Acid as a Modifier of Body Composition in Pigs

Pigs were fed one of four dietary additions of pantothenic acid (PA, 0, 30, 60, and 120 ppm) to determine the effect of PA additions on growth, body composition, and meat quality of pigs fed from 10 to 115 kg of body weight (BW). Fifteen sets (7 barrows, 8 gilts) of four littermate pigs from a high lean strain were used. Pigs were individually penned and reared via SEW scheme. Pigs were self-fed a diet containing 19 ppm PA from weaning to 10 kg BW. Pigs were then fed a 6 ppm PA basal diet and allotted within litter to one of four dietary additions of PA from d-calcium pantothenate. As dietary PA concentration increased, longissimus muscle area increased quadratically (43.9, 48.0, 45.4, 47.5 cm2, P = .06) and 10th rib backfat decreased quadratically (2.25, 2.04, 2.07, 1.95 cm, P \u3c .05) resulting in a quadratic increase in fat-free lean (51.4, 53.4, 52.5, 53.6%, P \u3c .04). Daily body weight gain (933, 916, 940, 914 g) and feed:gain (2.34, 2.32, 2.34, 2.33 kg/kg) were not altered by dietary PA. In addition, measures of meat (longissimus) quality, including intramuscular fat content (4.4, 4.2, 4.6, 4.0%), Hunter L (54.5, 54.2, 54.3, 54.3), and Hunter a (8.7, 9.1, 8.9, 8.5) color values and water loss under retail storage (4.7, 4.9, 5.1, 4.7%) at 96 hours post-kill were not (P \u3e .10) altered by dietary PA. Based on these data, dietary pantothenic acid at concentrations greater than that required to maximize body weight gain elicits reductions in subcutaneous fat thickness while increasing carcass lean content of market weight pigs without altering meat quality

Dietary Riboflavin Needs for Body Maintenance and Body Protein and Fat Accretion in Pigs

The dietary bioavailable riboflavin needs for body maintenance and body protein and fat accretion were estimated in pigs. The riboflavin required to support body protein accretion was higher than that for body maintenance or fat accretion. Specifically, the riboflavin required to support protein accretion was six times higher than the riboflavin required to support fat accretion. Based on these data, both biological and environmental factors that alter body protein accretion in pigs will substantially alter riboflavin needs. In addition, the dietary bioavailable riboflavin required by high-lean, high-health pigs is greater than the current NRC (4) estimate

Evaluation of the Antimicrobial Activity of Natural Animal Proteins/Peptides In Vitro

The objectives of this research were to validate the sensitivity and precision of an in vitro assay for evaluating the efficacy of antimicrobials, to evaluate the ability of natural animal proteins/peptides to kill in vitro antibiotic-resistant, as well as, -susceptible bacteria, and to determine the effects of key components of animal digesta (e.g., pH, mineral content, and proteolytic digestive enzymes) on the estimated antimicrobial activity of these proteins/peptides. The minimum inhibitory concentrations (MIC) for polymyxin B (control antibiotic) were determined to be .76, .76, and .90 µg/mL for Escherichia coli, Escherichia coli (nalidixic acid-resistant), and Staphylococcus aureus, respectively. The intra- and inter-assay variation for MIC determination was .18 and .2%, respectively. The natural animal proteins and peptides (lactoferrin, lactoferricin B, hen egg lysozyme, and alpha-lactalbumin LDT2) were determined in in vitro (acetic acid medium) to kill selected bacteria. Each of the tested proteins/peptides was active against an antibiotic-resistant (nalidixic acid) strain of E. coli; however, the required concentrations for antimicrobial activity were 10 to 15 times higher than that of the nonantibiotic-resistant strain. The antimicrobial activity of each protein/peptide in animal digesta fluid was 130 to 300% greater than that in the acetic acid media. Overall, the intra- and inter-assay variation values for the tested proteins/peptides was 3 and 3.4%, respectively. The antimicrobial activity of two of the three proteins/peptides was not affected by the presence of cationic minerals. The change in pH (digesta fluid and acetic acid media) from 7 to 2 resulted in a loss of antimicrobial activity of 33% for all proteins/peptides. Therefore, the increase in antimicrobial activity associated with the digesta fluid is not related to change in H or the mineral concentration of the digesta. Based on these data, natural proteins/peptides represent potential antibiotic substitutes

Dietary Available Phosphorus Needs of High Lean Pigs Fed from 9 to 119 kg Body Weight

Eighteen replicates (9 barrows, 9 gilts) were used to estimate the dietary available phosphorus (AP) needs of a high lean strain of pigs during each of four stages of growth (9 to 37, 37 to 65, 65 to 92, and 92 to 119 kg body weight [BW]). Pigs were self-fed a basal diet supplemented with one of six incremental additions of AP from monodicalcium phosphate. Initially (9 to 37 kg), pigs were fed a .16% AP diet supplemented with 0, .08, .16, .24, .32, or .40% AP. After each 28 ± 3 kg of BW gain, the AP concentration of the basal diet as well as the incremental additions of AP were reduced to 80% of that fed during the previous growth stage. Estimated dietary AP needs were similar between barrows and gilts. Daily dietary intakes of AP estimated to maximize body weight gain and gain/feed ratios were estimated as 3.15, 5.6, 4.95, and 4.95 g, respectively, for animals fed from 9 to 37, 37 to 65, 65 to 92, and 92 to 119 kg BW. These daily intakes were achieved with dietary concentrations of AP of .30, .26, .17, and .16%, respectively. Intakes of AP below the estimated needs resulted in negative biological and economical consequences

Quantitative Effect of Porcine Reproductive Respiratory Syndrome Virus on Pig Growth and Immune Response

Forty-eight pigs from a herd naïve for porcine reproductive respiratory syndrome virus (PRRS) were weaned, placed in isolation chambers, and oral-nasally inoculated with 2 ml of 10 4 JA142 PRRS virus. For each pig, body weight, feed intake, and serum concentration of PRRS virus titers, gamma-interferon (γ-IFN), and alpha-1- glycoprotein (AGP) were determined every 4 days for 24 days post-inoculation to determine the effect of PRRS exposure on growth and immune response in pigs and to quantify the relationship between serum virus concentration and pig growth. Serum virus titers and γ-IFN, both peaked at 4 days post-inoculation, and then declined steadily throughout the 24 day study. As expected, serum AGP responses were delayed with peak concentrations occurring 12 days post-inoculation. Body weight gains and feed intakes of individual pigs were quantitatively related to the animal’s serum concentration of virus titers and to a lessor degree to serum concentration of γ-IFN and AGP. Specifically, each additional 10-fold of serum virus titer was associated with a mean reduction of .018 kg in daily pig gain and .028 kg in daily pig feed consumption. These data indicate that the magnitude of biological responses that occur in pigs infected with PRRS is directly related to the animal’s serum virus concentration

Effect of Gestational Folic Acid Supplementation of Sows on Offspring Muscle Development and Postnatal Growth Response

Pairs of littermate, primiparous sows were penned individually and fed daily 1.9 kg of a low folic acid (FA) (.28 mg/kg) basal diet supplemented with 0 or 8 mg of FA from mating through parturition. All sows were fed the basal diet for 112 days prior to breeding to minimize the sows initial body folic acid stores. FA supplementation in sows during gestation resulted in elevated concentrations of serum FA. However, FA supplementation did not affect litter birth weight, litter muscle, fat, or bone weights, or litter DNA and protein content of three individual muscles at birth. FA supplementation of the sow also did not affect the offspring’s body weight gain, feed intake, and gain:feed ratio from body weights of 13 to 107 kg. Based on these data, a dietary folic acid regimen of .3 ppm (.53 mg/day) during pregnancy supports normal muscle growth in pigs pre- and postnatall