Impact of necrotic enteritis on the growth curve and the evaluation of test parameters for measuring coccidial infection

Necrotic enteritis (NE) and coccidiosis are two pervasive diseases within the poultry industry.Necrotic enteritis has been shown to exhibit both immediate and sustained effects on body weight (BW) of broilers.While coccidiosis is commonly associated with NE, some reports suggest NetB+ Clostridium perfringens (CP) can cause NE in the absence of Eimeria or other predisposing factors.Three experiments were completed which evaluated the immediate effect of NE on BW and impact on the growth curve of broilers when NE was induced by various methods.In experiment 3.1, a dual infection model of Eimeria maxima (EM) and CP was compared to a non-challenged control (NC), while experiment 3.2 evaluated two different strains of EM dual infection, as well as six CP-only groups.Similarly, experiment 3.3 tested dual infection and CP-only groups.In all three experiments, BW was measured immediately before infection, then weekly through the end of the test period.In all three experiments, a decrease (p<0.05) in BW was observed immediately following the acute NE disease period of d21 -d23, with a long-term effect on the BW most clearly detected in the EM + CP dual infection models, and when high levels of CP-only were administered.Experiment 3.1 clearly maintained these differences in BW in an almost parallel fashion through the termination of the experiment on d35, with NC observed as 2,182.0± 29.5 g versus 1,967.1 ± 23.7 g in EM Guelph dual infection group (p<0.001).Experiment 3.2 resulted in a similar parallel trend iii in BW in EM M6 dual infection group compared to NC, but no statistical differences in BW with NC were observed following d22.Three groups in experiment 3.3, the EM M6 dual infection group and two CP only groups, resulted in differences (p<0.05) for several weeks following the challenge period, returning to similarity with NC by d42 and d35, respectively, but the parallel growth with NC continued to be observed through the entire trial, d56.In addition to showing the long-term impact of various forms of NE on broiler growth, these shifts can be used to measure the effects of treatments on prevention and recovery of broilers impacted by NE.With regard to coccidiosis, a variety of test parameters is used to measure the effectiveness of treatment strategies, such as lesion scores (LS), performance parameters such as body weight gain (BWG) and feed conversion ratio (FCR), and occasionally oocysts per gram of feces (OPG).Each of these parameters provide varying insight into the impact of Eimeria, may be subjective, and some are possibly influenced by non-disease related activity.Four experiments were completed that examined at least two test parameters that included BWG, LS, and OPG, for measuring the impact of coccidial infection in chickens and turkeys.In experiment 4.1, a challenged control (CC) was measured against three anti-coccidial groups (AC 1-3), while in experiments 4.2-4.4,non-challenged (NC) and CC were compared via BWG and OPG, plus LS in experiments 4.1, 4.3, and 4.4.In all experiments, an Eimeria challenge was orally administered.In experiment 4.1, CC displayed the highest BWG during the infection period and AC 3 showed the lowest at 404.55±19.69g and 327.46±15.42g, respectively (p<0.05), with a lack of statistical differences in LS.At 6 days post infection, peak oocyst shedding closely reflected BWG with the lowest knowledge.I am grateful for the people who have helped me on my way to reaching my potential, and would not be where I am today without you all.I would like to express my sincere appreciation to the members of the OARDC Poultry Health Lab.Whitney Briggs, your dedication to keeping this lab organized seems unmatched.I cannot express how much I appreciate the way you keep this lab running like a well-oiled machine, making it look easy when I know it is anything but easy.Thank you for your friendship, advice, endless assistance and patience, and for the shared laughter.Kim Wilson, thank you for your time, dedication, and always having a smile.Audrey Duff, my word guru, it is a pleasure and a privilege to have you as a friend.The constant laughter we have shared makes the days more enjoyable as they fly by.Thank you for being available, both inside and outside of the lab, to make graduate life a bit more bearable.Dr. Lisa Bielke, I am indebted to you for taking me into your lab, nurturing my potential, and helping me recognize my abilities.I am inspired by your intelligence, dedication, and work ethic and I will be forever grateful to the opportunities you have afforded me.I am excited to

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