The effect of nutritional status on host response to artificial coccidiosis challenge, health, productivity and caecal microbiome diversity in different types of poultry

Akinci, Ibrahim (2021) The effect of nutritional status on host response to artificial coccidiosis challenge, health, productivity and caecal microbiome diversity in different types of poultry. PhD thesis, University of Nottingham.

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The main objective of this thesis was to investigate the effect of Eimeria infection on host immune response, health, productivity and caecal microbiota at different nutritional levels in different types of poultry.

After the overall introduction in Chapter 1, we assessed the prevalence of Eimeria infection in different agro-ecologies of Ethiopia showing that coccidiosis represents a major disease challenge across the country. In particular, in Chapter 2, we focused on assessing through the whole-genome shotgun sequencing of caecal content from 243 birds from 26 population across Ethiopia the prevalence of Eimeria species. Six hundred seventy Eimeria sp. specific gene regions were identified and used as genetic markers to assess the prevalence of Eimeria spp. A 76% overall prevalence was found with 185 out of 243 chickens infected with at least one of the Eimeria species. E. tenella and E. necatrix showed the highest prevalence with 49% and 47% prevalence, respectively. Low altitude and high temperature showed a positive correlation (P < 0.05) with the prevalence of E. necatrix and E. brunetti. There was also a positive relationship between precipitation and the prevalence of E. maxima, E. mitis, E. praecox and E. acervulina (P < 0.05).

In Chapter 3, we reported the results of controlled coccidiosis challenges on commercial chicken lines (Ross 308 broiler, Hy-Line Brown layer and H&N Nick layer). Birds were infected with the 10 X Paracox (MSD Animal Health) live vaccine at two nutritional levels (ad libitum and 10% restricted feed). The results showed that an overdose (x10) of the Paracox live vaccine was not reliably able to create pathogenicity. However, background coccidiosis shows that the broiler had greater lesion scores and a greater number of oocysts shed compared to the layer and pullet lines (P < 0.05). Feed restriction reduced body weight, weight gain and egg production (P < 0.05). Feed restriction improved FCR in the layer but worsened it in the broiler (P < 0.05).

In Chapter 4, a different challenge model was used to examine the coccidiosis infection and the resulting immune response at various nutritional levels in Ross 308 broilers. Chickens were challenged with 10,000 dosages (oocysts) of the Houghton laboratory strain of Eimeria tenella. The factors were two types of feeding (ad libitum and restricted feed) and coccidiosis challenge or not (with and without E. tenella inoculation). The results show that challenged birds had significantly higher lesion scores (P < 0.05). Chickens with feed restriction and Eimeria challenge had the lowest body weight (P < 0.05). The chickens with feed restriction and Eimeria challenge showed less resistance against coccidiosis compare to the ad libitum challenged chickens (reduced body weight and higher lesion score). Eimeria challenged chickens had higher serum interleukin 10 level and oocysts shed than non-challenged birds (P < 0.05), however, feed restriction did not affect the serum Interleukin 10 (IL-10) level.

In Chapter 5, we aimed to investigate the Eimeria infection at different nutritional levels on chicken immune response, health, productivity and caecal microbiome diversity in a dual-purpose (Sasso T451A) and a commercial so-called ‘fast growing’ broiler (Cobb 500) breeds. The same challenge and feed restriction model were used that the one described in Chapter 4. The results showed that E. tenella challenge groups had significantly more gut lesions and a higher level of IL-10 (P < 0.05) in both breeds. Eimeria challenge in Sasso T451A chickens reduced the body weight compared to non-infected counterparts (P < 0.05), but no difference in body weight was observed in Cobb 500. The results also showed that feed restriction shaped both bird types' responses to the coccidiosis threat but in different ways. In Cobb 500, feed restriction was linked to a lower disease tolerance (more gut lesions), but it was associated with improved disease resistance (minor gut lesions) and less weight loss in Sasso T451A chickens. An increase in Bacteroides and a decrease in Corynebacterium and Propionibacterium in infected chickens for both breeds were found. Also, a significant reduction in the family of Ruminococcaceae and an increase in the family of Enterobacteriaceae were found in infected Sasso T451A chickens.

Chapter 6 present an overall discussion of the results of the thesis. Further studies are needed to fully understand and document the effect of coccidiosis and the resulting immune response, especially in different breeds like egg-laying hens (during the laying period) and local indigenous chickens. Further molecular works, like protein and functional diversity analysis, may also contribute to a deeper understanding of the relationship between the host and coccidiosis.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Hanotte, Olivier
Goodacre, Sara
Keywords: nutritional status, host response, artificial coccidiosis challenge, health, productivity, caecal microbiome diversity, poultry
Subjects: S Agriculture > SF Animal culture
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Life Sciences
Item ID: 66054
Depositing User: Akinci, Ibrahim
Date Deposited: 31 Dec 2021 04:40
Last Modified: 31 Dec 2023 04:30

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