176 Impact of dietary crude protein level and water-based arginine on piglet growth and scouring with an Enterotoxigenic Escherichia coli F18 challenge

Abstract

Abstract The objective of this experiment was to evaluate the impact of dietary crude protein (CP) level and water-based arginine (Arg) on the growth performance and scouring of piglets post wean and following an enterotoxigenic Escherichia coli F18 infection (ETEC). A total of 240 pigs (PIC 337 x 1050, Genus, Henderson, TN) were randomly assigned to 40 mixed-sex pens (6 pigs/pen) for a 6-wk experiment. At arrival, all pigs were genotyped for fructosyltransferase (FUT1). Pens were assigned to one of four treatments in a 2 x 2 factorial, with two crude protein levels (standard: 23% vs. low: 19.5%, for period 1) and two water treatments (absence or presence (8, 6, and 4% stock dosed through 1:128 proportioner for wk 1, 2, and 3, respectively) of Arg in water. Pig body weight (BW), feed disappearance (average daily feed intake; ADFI), and feed conversion (gain to feed ratio; G:F) were evaluated for four periods: d 0-7, 7-14, 14-21, and 21-42. Scour scores were recorded daily for the first 28 d to calculate weekly percentage of days scouring (scouring percentage). On d 21, water and dietary treatments ceased, and pigs received a common diet. All pigs were orally inoculated with a field strain of ETEC for two consecutive days on d 15 and 16 of the experiment. One pig per pen had blood collected (8mL via jugular) and was euthanized on d 14 before ETEC. Blood was collected via a jugular vein from another pig confirmed to be susceptible to ETEC on d 15, 17, and 22. The same pig was euthanized for tissue collection on d 22. Fecal swabs from 1 susceptible pig per pen were collected on d 15, 17, 19, and 22 for measurement of ETEC shedding. Blood samples were analyzed for inflammatory markers, and villi: crypt within the ileum were measured. Data were analyzed using mixed model methods (SAS 9.4, Cary, NC) with pen as the experimental unit. Growth performance and scouring percentage included the fixed effects of CP level, water treatment, experimental period, and their interactions. Reducing the CP of diets reduced the overall G:F of pigs (P < 0.01, standard: 0.73, low: 0.71). The percentage of days scouring tended to be influenced by the interaction between water and period (P = 0.06); specifically, when arginine (Arg) was present in the water, there was a numerically greater scouring percentage for all periods, except for the final period (d 21-28). Confirming the success of the ETEC challenge, period significantly impacted scouring percentage (P < 0.01), where piglets experienced the greatest scouring percentage (59%) during the week following ETEC inoculation, compared with the least in the week preceding inoculation (22%). In conclusion, low CP diets reduced overall G:F, but neither CP or Arg showed benefit in terms of scouring.