Effects of dietary protein supply, weaning age and experimental enterotoxigenic Escherichia coli infection on newly weaned pigs: performance

Abstract

An experiment was conducted to investigate the effects of post-weaning dietary protein supply and weaning age on the performance of pigs in the absence of in-feed antimicrobial growth promoters (AGP) when artificially challenged with enterotoxigenic Escherichia coli (ETEC), a pathogen associated with post-weaning colibacillosis (PWC). The experiment consisted of a complete 2 3 2 3 2 factorial combination of two weaning ages (4 v. 6 week), two levels of dietary protein (H, 230 g CP/kg v. L, 130 g CP/kg) and challenge with ETEC (1 v. 2). An additional four treatments were added to test for the effects of protein source (DSMP, dried skimmed milk powder v. SOYA, soybean meal) and AGP inclusion (yes v. no) on challenged pigs of both weaning ages. At weaning (day 0), pigs were assigned to one of the experimental treatments for 2 weeks. On day 14 post-weaning, the same standard grower ration was fed to all animals until 10 weeks of age. On day 3 post weaning, challenged pigs were administered per os with 10 9 cfu ETEC. The ETEC challenge had a detrimental short-term effect on performance, decreasing average daily gain (ADG) (days 3 to 6; P 5 0.014) in both 4-and 6-week weaned animals. Compared with their non-infected counterparts, challenged 4-week weaned pigs on the H diet demonstrated a larger decrease in ADG immediately post infection than those on the L diet, 242% and 225%, respectively (P 5 0.088). This effect was smaller in the 6-week weaned pigs, 226% and 219% for the H and L diets, respectively. Pigs fed SOYA had lower (P , 0.001) daily intake and ADG (day 0 to 14) than those fed DSMP, with 6-week weaned pigs being affected to a greater extent than 4-week weaned pigs. In the absence of AGP, increasing weaning age and decreasing dietary protein level, especially in earlier weaned pigs, may help to minimise the effects of PWC on performance, particularly in sub-optimal environments.

Effects of dietary protein supply, weaning age and experimental enterotoxigenic Escherichia coli infection on newly weaned pigs: health

“…The experimental model used here produced prolonged faecal ETEC excretion in all challenged pigs post infection. No pigs died and/or showed signs of clinical PWC, although feed intake and growth rate were temporarily impaired (see Wellock et al, 2008). This suggests that the aim of inducing sub-clinical PWC was successfully achieved.…”

“…Alternatively, it may be a consequence of using the same experimental dose for both weaning ages, rather than making this weight dependent. However, as there was no significant correlation between BW on day of infection and average daily gain as a percentage BW over the immediate post-infection period (days 3 to 6) (see Wellock et al, 2008 for details); this suggests that BW at infection was less important than weaning age.…”

“…At weaning, pigs were given ad libitum access to one of four experimental diets for 2 weeks: a high protein (H, 230 g/kg CP) and a low protein (L, 130 g/kg CP) both with DSMP (H-DSMP and L-DSMP, respectively); a high protein where DSMP was replaced with soyabean meal (H-SOYA) and H-DSMP with ZnO (3100 mg/ kg), Cu (170 mg/kg) and avilamycin (Maxus G200, Elanco Animal Health Ltd, UK; 40 mg/kg) (H-AGP). For further details of the experimental diets, see Wellock et al (2008). On day 14 post-weaning, a standard grower ration was fed to all animals until 10 weeks of age.…”

“…Performance of the remaining animals was monitored until 10 weeks of age (see Wellock et al, 2008). The Animal Experiments Committee of the Scottish Agricultural College …”

“…An analysis of the data regarding the effect of experimental treatment on post-weaning performance is reported separately (Wellock et al, 2008). It was hypothesised that reducing protein availability in the distal small intestine, through reducing dietary protein content and/or substitution of existing ingredients, mainly soya, with the more digestible dried skimmed milk powder (DSMP), and increasing weaning age would reduce ETEC proliferation and improve the enteric health of the newly weaned pig.…”