Dietary Available Phosphorus Needs of Pigs From 13 to 70 Pounds Body Weight

Pigs were self-fed one of six dietary concentrations (.20, .30, .40, .50, .60, .70%) of available phosphorus (AP) from 13 to 70 pounds body weight. Dietary available phosphorus concentrations of at least .50, .40, and .40% were needed for pigs weighing 23, 43, and 63 pounds, respectively, to maximize daily body weight gains and gain:feed ratios. Based on these data, the dietary AP needs of 13- to 70-pound pigs experiencing a moderate level of antigen exposure are 1.25 to 1.5 times greater than current NRC (1) estimates for similar weight pigs

Dietary Thiamin Needs of High Lean Growth Pigs

Ten sets of five littermate pigs with a high genetic capacity for lean tissue growth (350 to 370 g/day) and reared via a segregated-early-weaning scheme were used to determine the dietary thiamin needs of pigs exhibiting a high rate of lean tissue growth. Within each litter, pigs were randomly allotted to one of five dietary thiamin concentrations equivalent to 200, 330, 460, 590, and 720% of the current NRC (1988) estimated requirement for 11 to 22 pound pigs. Pigs were penned individually and given ad libitum access to experimental diets and water from 22 to 88 pounds body weight (BW). Pooled across diets, the pigs’ body weight gains and feed:gain ratios averaged 1.70 pounds per day and 1.44 pounds, respectively, from 22 to 88 pounds body weight. Dietary thiamin concentration did not alter daily feed intake, rate of body weight gain, or feed:gain ratios. Based on these data, dietary thiamin in a corn-soy-based diet (2.2 ppm) is adequate for optimal rate and efficiency of gain in high lean growth pigs from 22 to 88 pounds body weight

Dietary Vitamin A, E, and C Needs of Pigs Experiencing a Low or High Level of Antigen Exposure

The impact of dietary vitamin A, E, and C concentration on rate and efficiency of body weight gain and serum vitamin E (a-tocopherol) concentration was determined in pigs experiencing a low or high level of antigen exposure (AE). Pigs were reared via two management schemes that resulted in either a low or high level of AE. Dams of the pigs received a corn and soybean meal diet devoid of supplemental vitamins A, E, and C from day 60 of pregnancy through lactation. Postweaning, pigs were individually penned and self-fed a basal diet containing 25% of the estimated requirement (1) for 11–22 lb pigs for vitamins A and E, and 3.64 mg of vitamin C per pound of diet. At 21±2.6 lb body weight, pigs within a litter were randomly allotted to the basal diet supplemented with vitamins A, E, and C equivalent to 0, 100, 200, 300, and 400% of NRC (2 mg of C added per 1 IU of E). Low AE pigs had lower serum alpha-1 acid glycoprotein concentrations (466 vs 726 mg/mL) indicating they experienced a lower level of AE. Low AE pigs also gained body weight faster (1.39 vs 1.27 lb/day) and required less feed per unit of gain (1.37 vs 1.45) than high AE pigs fed from 21 to 55 lb body weight. As dietary concentrations of A, E, and C increased, daily gains increased quadratically, but the magnitude of response was greater for the high AE pigs. Serum vitamin E concentrations increased with increasing dietary concentrations of vitamins A, E, and C in low AE pigs but remained constant in high AE pigs. Based on these data, dietary needs for one or more of vitamins A, E, and C are greater in pigs experiencing a high versus low level of chronic antigen exposure. Furthermore, the needs of high-antigen-exposed pigs are greater than current estimated requirements (1)

Impact of Level of Antigen Exposure on Response of Pigs to Dietary Energy Sources

Two levels of chronic antigen exposure (moderate and high) were created by rearing pigs via a segregated-earlyweaning and a conventional rearing scheme, respectively. In each antigen exposure group, three littermate pigs in each of nine litters were fed one of three energy sources from 13 to 60 pounds body weight. Fifteen percent of the metabolizable energy (ME) content of the diets was provided by corn starch (CS), choice white grease (CWG), or corn oil (CO). Moderate AE pigs consumed more ME per day and grew faster than high AE pigs. The dietary inclusion of fat calories (CWG, CO) for starch calories resulted in greater daily body weight gains and gain:ME ratios in both moderate and high AE pigs. The magnitude of growth responses to the two fat calorie sources was similar in both AE groups. Based on these data, dietary fat calories support greater growth rate and efficiency of dietary ME utilization than starch calories in pigs experiencing either moderate or high levels of antigen exposure

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

Impact of Dietary Energy Source on the Responses of Pigs to an Acute Level of Antigen Exposure

Two trials were conducted to determine the response of pigs experiencing a low or high level of acute antigen exposure to three dietary energy regimens: a low-fat basal diet, basal diet plus 6% added choice white grease (low linoleic acid), and basal diet plus 6% added corn oil (high linoleic acid). All pigs were reared via a segregated early weaning scheme to minimize the pigs’ exposure to environmental antigens and thus level of immune system activation. Three littermate pigs in each of 24 litters were allotted at 21 days to one of the three dietary energy regimens for 37 days. Onehalf of the pigs in each trial were administered lipopolysaccharide (LPS), an acute stimulant of the immune system, on day 21 of the trial and again eight days later. LPS administration resulted in a short-term acute depression in pig performance in both trials. The magnitude and duration of the pigs’ response to LPS differed between trials and thus results are reported separately. Prior to antigen (LPS) administration, dietary fat additions resulted in faster daily gains in trial 1 and greater efficiency of dietary energy (metabolizable energy, ME) utilization in trials 1 and 2. Responses to the two fat sources were similar in both trials. During the period of acute antigen exposure (day 0 to 4 post-LPS), daily weight gain and gain:ME ratios were similar among the three dietary regimens in both AE groups. Following partial antigen clearance from the body (day 4 to 8 post-LPS), dietary additions of either fat source again resulted in faster daily gains in trial 1 and improved gain:ME ratios in trial 2 in both AE groups. Based on these data, dietary additions of fat (both low and high in linoleic acid content) result in greater growth rates and efficiency of dietary ME utilization in pigs both prior to and following a period of acute antigen exposure

Effects of Source on Copper Uptake by Swine

Four catheterized crossbred (Y x H) barrows were used in a 4 x 4 latin square arrangement of treatments in a completely randomized block design, to determine the effect of source on copper uptake as determined by serum Cu concentration changes over a 7.5-hr sampling period

Effects of Source on Copper Uptake by Swine

Four catheterized crossbred (Y x H) barrows were used in a 4 x 4 latin square arrangement of treatments in a completely randomized block design, to determine the effect of source on copper uptake as determined by serum Cu concentration changes over a 7.5-hr sampling period