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

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

Establishment of the Minimum Biological Capacity for Nitrogen Excretion in Pigs

To determine the minimum biological capacity for nitrogen (N) excretion for pigs, dietary regimens were created and fed that were designed to eliminate fecal excretion of undigested feed N, minimize endogenous N secretions and minimize intakes of nitrogenous compounds (amino acids) above those of the pigs biological needs. Excretion of undigested fecal N was eliminated by feeding ingredients containing highly digestible (≈100%) sources of nitrogen and by eliminating compounds that bind N. Endogenous secretions were minimized by eliminating antinutritional factors from the diet and by minimizing enteric bacterial populations. Intakes of amino acids above the animal\u27s needs were minimized by providing a pattern of amino acids that closely matched that needed by the pig. Furthermore, dietary amino acids were provided to the pigs in amounts above, at, and below their biological needs based on the amounts of urea N excreted in the urine and the amounts of N accrued in the body. From two-slope breakpoint analysis, apparent digestible N intake resulting in maximum N retention (2.58g⋅kg-1BW.75⋅d-1) was determined to be 3.66g⋅kg-1BW.75⋅d-1. When daily apparent digestible nitrogen intakes were below the pigs\u27 determined need, the amount of digestible N (mg⋅kg-1BW.75⋅d-1) lost for body maintenance processes was estimated as .239 in urine and .080 in feces. The amount lost in urine as unusable for body N accretion was .206 g⋅kg-1BW.75⋅d-1 of each gram of digestible N consumed above body maintenance needs. When daily apparent digestible N intakes were above the pigs determined need, .900 g of each gram of additional N consumed above that needed for body N accretion was excreted. The minimum biological capacity for N excretion in pigs, defined as total (urinary plus fecal) obligatory losses of N, is estimated to be .287g⋅kg-1BW.75⋅d-1 to support pigs at N maintenance and 1.11 g⋅kg-1BW.75⋅d-1 for pigs at maximum body N accretion. Using these estimates, the minimal biological capacity for N excretion can be calculated for pigs at various stages of growth. For example, in 60 kg pigs, minimum capacity for N excretion is estimated at .10 and .39 g/kg body weight/day in pigs in states of N maintenance and maximum body N accretion, respectively. These values are 12 and 44%, respectively, of N excretion relative to published standards (ASAE D384.1). Similarly, the N content of excreta from animals excreting N at their biological minimum was determined to be 2.57 g N/liter, or 18% of standard excreta N content (corrected for volatilization, ASAE D384.1). Based on these data, the minimum biological capacity for the excretion of N in pigs is substantially less than current estimates of N excretion and can be achieved by eliminating dietary factors that contribute to N excretion. Furthermore, dietary regimens that allow the minimum biological capacity for N excretion to be achieved are biologically capable of supporting maximum rates of body accretion (i.e., lean tissue growth) in pigs