Enzymatically treated yeast to affect gut integrity and growth performances of Eimeria challenged broiler

Eimeria is known to cause coccidiosis, an endemic disease, that has been estimated to induce losses of US$ 0.17/ slaughtered chicken in North America. The aim of this study was to evaluate an enzymatically treated yeast (LivaltaCell HY40, Livalta, UK; HY40) on gut integrity and growth performance of Eimeria sp. challenged broiler chickens. Eighty-four groups of 30 male broiler chicks (Cobb 500) were allocated to one of 7 dietary treatments, containing either 0, 0.05, 0.2, 0.8 or 3.2% HY40 (treats C, D, E, F, G), formulated in corn and soybean meal- based diets in four phases: 1 (d 0-7), 2 (d 8-21), 3 (d 22-33) and 4 (d 34-42). Treats A and B contained coccidiostats in phases 1, 2 and 3. On d 14, birds in treats B to G were challenged with a blend of Eimeria tenella (2,000 oocyst/bird), E. acervulina (25,000 oocyst/bird) and E. maxima (10,000 oocyst/bird) by oral gavage, whilst birds of treat A received a saline solution. Growth performance parameters (body weight, BW; feed intake; feed conversion ratio, FCR) were recorded on d 7, 21, 33 and 42. Jejunal and caecal digesta oocysts counts (OC) were measured on d 21 and 42. Birds were scored for lesions (LS) at duodenum for E. acervuline, jejunum for E. maxima and ceca for E. tenella at d 21. Lowest OCs were found throughout for treat A and no treat effects on d 42. On d 21, treat B effectively reduced (P<0.05) jejunal OC compared with treat C. In birds of treat E, F and G caecal OCs were reduced (P<0.05) compared with treat D. Birds of treats A and B had minimal gut lesions (LS 0 and 7) whereas treats C and D had highest LS (33 and 33). Starting from 0.2% HY40, treat E, F and G, LS was strongly reduced with 12, 13 and 11, respectively, compared with treat C and D. There was no differences (P>0.05) on growth performance between birds of treats A and B. Overall, birds of treat C had significantly reduced BW (-226g) and FCR (+7 points) compared with treat A. Whilst starting from 0.2% inclusion, treat E, F and G, HY40 significantly improved d 42 BW by 4% (+101g) and FCR by -6 points, reaching comparable FCR to birds treated with coccidiostat (treat A and B). In conclusion, HY40 can be an effective ingredient in poultry antibiotic-/ coccidiostat-free feeding systems to support welfare and performance of the birds.

Key Words: Enzymatically treated yeast, Performance, Eimeria challenge, Oocyst count, Broiler.

Presented at the International Poultry Scientific Forum at IPPE 2022 in Atlanta, USA.