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Food Safety and Heat Stress Response of Broiler Chickens Fed a Saccharomyces Cerevisiae Fermentation Product
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A study was conducted to 1) evaluate the effects of feeding S. Cerevisiae fermentation product on Salmonella prevalence and numbers in ceca, carcass, and parts of broilers reared in heat stress as well as to 2) evaluate the welfare of broilers fed S. Cerevisiae fermentation product and reared under heat stress temperatures. A total of 480 Ross broilers were fed control diet (CON) or S. Cerevisiae fermentation product (Original XPC™ Diamond V Mills, Inc Cedar Rapids, IA). Dietary treatments included control (CON), S. Cerevisiae fermentation product fed at 1.25 kg/MT (XPC), and S. Cerevisiae fermentation product fed at 2.0 kg/MT (XPC 2). Half the birds were subjected to either no heat or heat stress from 31 to 42 days. On D 3, Salmonella free chicks were gavaged with 0.25 ml of 10^7 CFU/ml of Novobiocin and Naladixic acid resistant Salmonella Typhimurium. At the end of the heat stress period, blood was analyzed from 40 birds per treatment for corticosterone (CORT), heat shock protein (HSP70), and heterophil/lymphocyte ratios (HL). On D 42, bilateral metatarsal traits were measured in 40 birds/T to assess physical asymmetry. Hocks and footpads were scored as a measure of bird welfare. Birds fed XPC or XPC 2 had significantly lower CORT levels than CON (P < 0.001). Physical asymmetry scores were higher (P < 0.001) in CON compared to XPC and XPC 2. HL ratios were greater in CON than XPC and XPC 2 birds (P < 0.01). No differences were observed between CON broilers and those fed XPC in HSP70. However, heat stress did increase (P < 0.001) HSP70. Feeding XPC did not significantly influence footpad or hock scores. On D 42 & D56, 8 birds per pen were processed following industry practices. Individual ceca (C), wing (W), right breast filet (BF), and ground left breast filet (GBF) were collected for Salmonella prevalence and enumeration. No significant two-way interactions between dietary treatment and environment were observed, so data was pooled for analysis. Salmonella prevalence was significantly lower in GBF for XPC fed birds (P < .046), indicating the potential for XPC to reduce Salmonella levels in ground meat.
Price, Paul Thomas (2016). Food Safety and Heat Stress Response of Broiler Chickens Fed a Saccharomyces Cerevisiae Fermentation Product. Master's thesis, Texas A & M University. Available electronically from