M. A. Tony 1, Wafaa A. Abd El-Ghany 2 and Samah H. Mohamed 3 1 Department of Nutrition and Clinical Nutrition, Faculty of Veterinary Medicine, Cairo University 2 Department of Poultry Diseases, Faculty of Veterinary Medicine, Cairo University 3 Department of Immunology, Animal Health Research Institute, Dokki, Egypt Influence of feed sanitation on zootechnical performance, immune status and prevalence of Salmonella typhimurium in broiler chickens

Consequently, it is important to control Salmonella in contaminated feed ingredients (Jones, 2008 and Ratcliff, 2006), as it is prudent to assume that all raw feed ingredients are contaminated with Salmonella. Salmonella strains in birds cause diseased or carrier state, whereas they are either maintained and shedded to affect environment and/or human health. Salmonella is a major microbial hazard in animal feed, as it can persist for long periods in a wide range of feed materials. Introduction

Formic and propionic acids alone or in combination are used as microbial inhibitors (Carter, 2006). Superior decontamination of feed by formaldehyde, compared with acid products, has been demonstrated (Smyser and Snoeyenbos, 1979). Some commercial formaldehyde based products may also contain organic acids or other antimicrobial compounds to minimize the effects of formaldehyde evaporation on antimicrobial activity (Carrique-Mas et al., 2007 and Trombetta et al., 2005). Introduction

Study and compare the efficacy of a commercial acidifier feed additive product containing formaldehyde (Dexanifeed ® ) at two doses (250g/ton and 500g/ton) on zootechnical performance, Salmonella Typhimurium prevalence, immune status and carcass yield of broiler chickens. The aim of the work

Experimental design 300 day old broiler chicks (4 replicates, 25 birds each) for 35 days C Non treated & infected (Control) T1 Treated (250 g/ton) & infected T2 Treated (500 g/ton) &infected Treatment

Measured parameters Zootechnical performance Body weight, feed consumption, body weight gain and feed conversion) were calculated weekly Signs, mortalities & gross lesions. After challenge orally with 10 6 CFU S. Typhimurium at 3 weeks old, the birds were observed for 2 weeks. Shedding & re- isolation rate Swabs were taken from the liver and intestine for at 5 weeks old. Humeral immunity (HI for NDV & ELISA for IBDV weekly). Innate immunity Phagocytic percent & index of peripheral blood mononuclear cells, serum lysozyme and nitric oxid). Carcass yield At 5 weeks old, Live body weight, dressing weight, dressing weight (%), liver and abdominal fat weight were detected.

Parameters Control Group (C) Dexanifeed ® treated Groups T1 (250 g/ton feed) T2 (500 g/ton feed) Body weight (g/bird) Body weight gain (g/bird) Feed Intake (g/bird) FCR 1985 ± 65.5 a 1945 ± 41.5 a ± 25.5 a ± 25.3 b ± 20.5 b ± 20.9 a ± 18.5 c ± 22.5 c ± 15.9 a 1.68 Performance parameters measured at day 35 of age (mean ± SD) Figures in the same row with different letters are statistically significantly different (p<0.05

Performance Parameters

Challenged birds showed signs of anorexia and watery diarrhea 4 days post infection. The severity of signs was recorded in (C) group than those consumed treatment by low or high doses. Post-mortem examination of dead birds revealed severe enteritis with mucoid intestinal contents and congestion of the intestinal mucosa.

Shedding rate of S. Typhimurium

R-isolation rate of S. Typhimurium

HI titers of NDV * Significant difference

ELISA optical densities (OD) of IBDV * Significant difference

Phagocytic percent of macrophages

Nitric oxid (μmol/ml)

Parameters Control Group (C) Dexanifeed ® treated Groups T1 (250 g/ton feed) T2 (500 g/ton feed) Live Body weight (g) Dressing weight (g) Dressing weight (%) Liver weight (g) Abdominal fat (g) 1990 ± 15.3 a ± 22.5 a ± 2.5 a ± 3.8 a ± 33.5 b ± 18.9 b ± 3.2 a ± 2.8 a ± 26.2 c ± 21.3 c ± 3.1 a ± 2.9 a Carcass yield measured at day 35 of age (mean ± SD) Figures in the same row with different letters are statistically significantly different (p<0.05).

Using organic acids with their salts and formaldehyde mixture (Dexanifeed ® ) as feed additives for feed sanitation reflected positively on the productive performance of broiler chickens, reduced the incidence of salmonellosis and enhanced the immune status of broiler chickens. Conclusion