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31st Annual Australian Poultry Science Symposium
The following technical article is related to the event::
31st Annual Australian Poultry Science Symposium

Efficacy of Synergistic Blend of Feed Additives on Growth Performance, Gut Health and Bird Welfare in Broilers Challenged with Necrotic Enteritis

Published on: 3/22/2022
Author/s : A. KUMAR 1, M. TOGHYANI 2, S.K. KHERAVII 1, L. PINEDA 3, Y. HAN 3, R.A. SWICK 1 and S.-B.WU 1 / 1 School of Environmental and Rural Science, University of New England, NSW, Australia; 2 School of Life and Environmental Sciences, The University of Sydney, NSW, Australia; 3 Trouw Nutrition R&D, The Netherlands.
A feeding study was conducted to examine the efficacy of a synergistic blend of feed additives on growth performance, livability, gut integrity, immunity, caecal microflora and footpad health in broilers challenged with subclinical necrotic enteritis (NE). Additives were: A) synergistic blend of medium chain fatty acids (MCFA), slow-release C12, target release butyrates, organic acids (OA) and a phenolic compound; B) synergistic blend of partly buffered OA with MCFA; C) synergistic blend of partly buffered OA with a high concentration of MCFA. A total of 1404 male Ross 308 chicks were assigned to 78 floor pens each stocked with 18 birds. A randomised complete block design was used with 6 treatments replicated 13 times and the treatments were: T1 - unchallenged group, without additives or in-feed antimicrobials; T2 - challenged group, without additives or in-feed antimicrobials; T3 - challenged group plus in-feed antimicrobial (Zinc bacitracin); T4 - challenged group plus additive A at 1.5, 1.5, 0.5 g/kg feed; T5 - challenged group plus additive B at 2.5, 2.0, 1.0 g/kg feed; T6 - challenged group plus additive C at 2.0, 1.5, 1.0 g/kg feed in starter, grower and finisher phases, respectively. Diets were based on wheat and soybean meal and were supplemented with xylanase and phytase. Challenged birds were given field strains of Eimeria spp. oocysts consisting of E. acervulina (5000), E. maxima (5000) and E. brunetti (2500) at d 9 and Clostridiumperfringens (Cp) at d 14 (108 CFUs/mL). Mortality data were used to correct the FCR. Bird performance was measured from d 0 to 35. Serum fluorescein isothiocyanate dextran (FITC-d) was used as a leaky gut marker to measure gut integrity; immunoglobulins and caecal microflora were measured at d 16. Footpad health and litter quality (Kheravii et al., 2017) were scored at d 35.
The unchallenged group had higher feed intake (FI), body weight gain (BWG), lower FCR, and serum FITC-d concentration compared to NE challenged groups (P < 0.05). BWG and livability were not significantly different among the challenged groups. Birds supplemented with feed additives had lower FCR compared to T2 (overall, P < 0.05). On d 16, a higher concentration of serum FITC-d was observed in T2 compared to feed additives groups (P < 0.05). Birds challenged with NE had a higher level of serum IgA but no effects were observed in serum IgG and IgM levels. Birds fed additive C had lower counts of Bacteroides spp. compared to T2 (P < 0.05). Birds fed additives had lower counts of Ruminococcus spp. than T2 (P < 0.05). Cp counts were not significantly different between additives B, C, and in-feed antimicrobial groups (P > 0.05). Birds treated with feed additives had lower footpad dermatitis (FPD) and hock burn scores (HB) compared to T2 (P < 0.05). There was a tendency to improve the litter quality in the additive groups (P = 0.072). However, a strong positive correlation between litter quality and FPD (r = 0.388, P < 0.0001) and HB scores (r = 0.581, P < 0.0001) was observed. These findings suggest that additives A, B, and C were effective in alleviating the impact of NE as indicated by improved FCR, enhanced gut integrity and improved bird welfare. These results also demonstrated that the diet supplemented with additive C helped to maintain good gut health by altering the intestinal bacterial population.
Presented at the 31th Annual Australian Poultry Science Symposium 2020. For information on the next edition, click here.

Bibliographic references

Author/s :
Dr Bob Swick holds the position of Industry Professor of Poultry Nutrition at UNE in Armidale, NSW, Australia. Bob holds a B.S. degree in Biology, M.S. in Animal Nutrition and Ph.D. in Animal Nutrition and Toxicology from Oregon State University. He began his career in the Nutrition Chemicals Division of Monsanto Company in the US, moved to Singapore with Novus International Inc and later became Technical Director for the American Soybean Association in Singapore. Bob has held consultancies with Swift Foods, Agrenco Group, Addcon, Prince Agri Products and Phibro Animal Health.
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