| dc.description.abstract |
Investigating chicken production systems, along with the ecotype's productive and
morphological traits, as well as the challenges and opportunities in chicken production is
crucial for developing sustainable breeding programs. The aim of the dissertation was to
phenotypically characterize the indigenous chicken ecotypes and evaluate the effect of
Enteromorpha prolifera polysaccharide on growth performance and anticoccidial efficacy.
The dissertation is based on four manuscripts mentioned as chapters (Chapter 4 - Chapter 7).
The first manuscript (Chapter 4) explores the husbandry practices and selection criteria of
chicken producers in Northwest Ethiopia. In this chapter, data collected from a total of 360
households from six districts (stratified into lowland, midland, and highland agro-ecologies)
was analyzed. In the study area, egg production performance was a priority by chicken owners
when selecting female chickens across all agro-ecologies. For male chickens, plumage color,
appearance, and growth rate were the main traits considered. Farmers primarily raised
chickens for income generation through the sale of eggs and birds. There were significant
differences among agro-ecologies in terms of chicken feeding management, housing, chicken
flock composition, brood modification methods, and reproductive performance traits. The
inbreeding coefficient was higher in the highland agro-ecology compared to the midland and
lowland areas. To enhance chicken productivity sustainably, breeding programs should align
with farmers' production objectives and trait preferences specific to each agro-ecology. The
second manuscript (Chapter 5) focuses on characterizing the morpho-biometric variations of
indigenous chicken ecotypes in Northwest Ethiopia. Sampling was done using a multi-stage
purposive, stratified, and random approach. Morpho-biometric data collected from a total of
1200 adult chickens were analyzed for 12 qualitative and 11 quantitative traits. Red plumage
color, white and red earlobe color, and yellow shank color were the most prevalent trait
categories. Body measurements were significantly influenced by sex, agro-ecology, location,
and the interaction of sex and location. Shank traits (Shank length and circumference)
x
exhibited high discriminatory power in both sexes. Female and male sample populations were
classified with overall rates of 57.47% and 69.97%, respectively. Significant squared
Mahalanobis distances were observed between locations/sites. Canonical variates analysis
separated sample populations based on location. Cluster analysis classified the indigenous
chickens into four ecotypes: ecotype 1 (Banja, Dembecha, and Aneded), ecotype 2 (North
Achefer), ecotype 3 (Sinan), and ecotype 4 (Jawi). The third manuscript (Chapter 6) was
based on an on-station comparison of the growth performance of indigenous chickens and
evaluates the effect of Enteromorpha polysaccharide (EP) supplementation on their growth. A
total of 180 indigenous chicken ecotypes (Sinan, Dembecha, North Achefer, and Jawi) were
used in the study. Both ecotype and sex had a significant effect on body weight and average
daily gain (ADG). Jawi ecotype exhibited the highest final body weight and ADG, followed
by North Achefer. Males had higher body weight and ADG than females. Enteromorpha
polysaccharide supplementation resulted in significantly higher body weight and ADG
compared to non-supplemented chickens. The interaction between ecotype and feed type was
not significant, except at week nine. Sinan ecotype showed the highest survivability rate in the
first four weeks. Overall, Jawi and North Achefer ecotypes performed better in terms of
growth, while Sinan ecotype showed relatively higher survivability. Supplementation of EP
showed potential for improving chicken growth. The fourth manuscript (Chapter 7) was
about the anticoccidial potential of Enteromorpha prolifera polysaccharide in indigenous
chickens in Northwest Ethiopia. The study included 78 male indigenous chickens divided into
two treatment groups: EP non-supplemented and EP supplemented. Each group had five
replications. After 14 days of EP supplementation, chickens were inoculated with 1.5×10
mixed Eimeria oocysts. The EP-supplemented chickens exhibited significantly lower oocyst
counts and less severe lesion scores compared to non-supplemented chickens. The EP
supplementation provided relatively a higher protection rate against lesions and resulted in
higher weight gain. Enteromorpha polysaccharide showed promise as a potential strategy for
combating coccidiosis in chickens. Further research is needed to understand the mechanisms
underlying its protective effects. |
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