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

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2018, Master of Science, Ohio State University, Animal Sciences.
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 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±19.69 g and 327.46±15.42 g, 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 shedding in CC and the highest in AC 3 at 183.67 x 103 and 482.33 x 103, respectively (p<0.05). In experiment 4.2, d0-7 BWG was the only observed difference (p<0.05) in BWG between NC and CC at 125.9 ± 1.0 g versus 131.1 ± 0.9 g, respectively. On the other hand, OPG were observed to be greater in CC than NC at d17 and d24 (p<0.05). In experiment 4.3, BWG remained unaffected throughout the infection period, but LS were stronger in CC at 0.90 ± 0.14 compared to NC at 0.45 ± 0.11 (p<0.05). Only experiment 4.4 resulted in decreased (p<0.05) BWG within CC at 192.52 ± 4.07 g versus 204.67 ± 3.56 g in NC during the challenge period. Increased (p<0.05) LS were observed within CC group in both the duodenum and ceca, the target areas of the Eimeria used. No OPG were detected in NC pens, while CC displayed three distinct peaks in shedding, with differences (p<0.05) detected at d21 with 14.12x103 ± 4.89x103 OPG and at d25 with 27.44x103±6.74x103 OPG in CC. Incorporation of OPG as test parameters to measure coccidiosis intervention strategies, along with BWG and LS, provides a comprehensive description of disease that may not otherwise be observed with the two latter measurements alone. These studies illustrate the value of non-traditional research methods that may offer strategies for testing effectiveness of intervention strategies against important enteric diseases of poultry.
Lisa Bielke (Advisor)
Ramesh Selvaraj (Committee Member)
Thaddeus Ezeji (Committee Member)
91 p.

Recommended Citations

Citations

  • Chasser, K. M. (2018). Impact of necrotic enteritis on the growth curve and the evaluation of test parameters for measuring coccidial infection [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523281345700585

    APA Style (7th edition)

  • Chasser, Kaylin. Impact of necrotic enteritis on the growth curve and the evaluation of test parameters for measuring coccidial infection. 2018. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1523281345700585.

    MLA Style (8th edition)

  • Chasser, Kaylin. "Impact of necrotic enteritis on the growth curve and the evaluation of test parameters for measuring coccidial infection." Master's thesis, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523281345700585

    Chicago Manual of Style (17th edition)