Avilamycin [HRP]

This study evaluated the effects of micro-encapsulated (protected) organic acids (OA) and essential oils (K) combination, P(OA + K), and effects of a regular blend of free acids (FA) on the growth, immune responses, intestinal barrier and microbiota of weaned piglets challenged with enterotoxigenic Escherichia coli (ETEC) F4 (K88(+)). A total of 30 crossbred (Duroc x Landrace x Large White) weaned barrows (7.41 +/- 0.06 kg, 28 d old) were assigned randomly to 5 treatments: 1) non-challenged positive control (PC), 2) ETEC F4 (K88(+))-challenged negative control (NC), 3) NC + kitasamycin at 50 mg/kg + olaquindox at 100 mg/kg + free acidifier (FA) at 5 g/kg, 4) NC + kitasamycin at 50 mg/kg + olaquindox at 100 mg/kg + P(OA + KO at 1 g/kg (P1), 5) NC + kitasamycin at 50 mg/kg + olaquindox at 100 mg/kg + P(OA + KO at 2 g/kg (P2). Each dietary treatment had 6 replicates of one piglet each and the study lasted for 3 wk. On d 7, pigs in NC, FA, P1 and P2 were orally dosed with 10 mL of ETEC F4 (K88(+)) culture (1 x 10(9) CFU/mL). From d 7 to 14 after the ETEC F4 (K88(+)) challenge, P1 increased gain-to-feed ratio (G:F) significantly (P < 0.05) compared with NC and FA groups. From d 14 to 21, P2 increased the average daily gain of pigs (P < 0.05) compared with NC and FA groups. Compared with NC, P2 reduced tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and IL-10 con-centrations (P < 0.05) in sera collected at 4 h later after ETEC F4 (K88(+)) challenge. On d 21, P1 increased occludin and zonula occludens-1 protein expression in ileum compared with NC (P < 0.05). After this 3-wk experiment, alpha diversity of gut microbiota was decreased by P2 compared with PC, and P1 increased the relative abundance of Lactobacillus in ileum, cecum and colon (P < 0.05). In conclusion, dietary P(OA + additive at 2 g/kg combined with antibiotics could improve piglet performance and attenuate inflammation, and P(OA + KO additive at 1 g/kg combined with antibiotics improved intestinal barrier and increased beneficial microbiota composition after an F4 (K88(+)) challenge. (C) 2020, Chinese Association of Animal Science and Veterinary Medicine. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

This experiment determined whether delayed weaning and outdoor rearing could compensate for the removal of antimicrobials from piglet diets. One hundred and sixty litters of Large White (75%) x Landrace (25%) pigs on the same unit were reared either indoors (In) or outdoors (Out) and weaned at either 4 or 6 weeks of age into flat deck accommodation onto diets supplemented with either no antibiotic growth promoters and no zinc oxide (Un) or 40 mg avilamycin and 3.1 g zinc oxide/kg diet (S). Piglet performance was monitored to 8 weeks of age. A proportion of litters (25%) were sampled to investigate the effect of the different treatments on gut development. Mortality was higher in the first 24 h of life for Out piglets which subsequently grew faster to weaning. This was not simply due to smaller litter size as total litter gain was higher in outdoor litters. All piglets responded positively to antimicrobial supplementation post weaning regardless of rearing environment and weaning age and this was the biggest influence on post weaning performance. Outdoor piglets grew faster than indoor piglets post weaning (295 versus 242 +/- 8.6 g/pig/day for the first 2 weeks post weaning, P<0.001) and over the same period 6 week weaned piglets grew faster than 4 week weaned (324 versus 213 +/- 8.6 g/pig/day, P<0.001), however, when compared at similar age. 6 week weaning was detrimental to piglet growth with average daily gain (adg) from 4 to 8 weeks of age 310 g/pig/day versus 329 for 4 week weaned piglets (P = 0.001). At 8 weeks of age the outdoor 6 week weaned unsupplemented piglets had similar average weight to the indoor 4 week weaned supplemented piglets indicating the potential of this combination to counteract the need for antimicrobials, however the benefit was due to enhanced weaning weight not to improved post weaning performance. (C) 2009 Elsevier B.V, All rights reserved.