So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

Indigenous/native breeds of chickens are playing an important role in rural economies in most of the developing and underdeveloped countries. They play a major role for the rural poor and marginalised section of the people with respect to their subsidiary income and also provide them with nutritious chicken egg and meat for their own consumption. Performance of native fowl can be improved by change in husbandry, feeding, and better health cover. However, genetic improvement may be made either through selection and crossbreeding or by utilisation of both selection and crossbreeding. Improvement through selection may be time consuming but the improvement will be permanent. Through crossbreeding improvement may be faster but research has to aim for the production of native-type birds with higher production potential. In the present review efforts have been made to present the importance of native fowl to rural economy and their improvement for higher production performance.

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Importance of Indigenous Breeds of Chicken for Rural Economy and Their Improvements for Higher Production Performance

2 Abstract: Indigenous chickens in Kenya are about 22 million and are kept by 90% of the rural communities in small flocks of up to 30 birds mainly under free range system. The industry is flexible and does not require a lot of space. When people retire or are retrenched they easily start poultry keeping. Distinct indigenous chicken ecotypes have been identified and named. The names are phenotypic descriptions of the birds. The names used to describe the common phenotypes in Kenya are-frizzled feathered, naked neck, barred feathered, feathered shanks, bearded and dwarf sized. The local ecotypes of the chickens vary in body size, conformation, plumage colour and performance. The birds are hardy and thrive under a harsh environment with minimal inputs. They get most of their feed from scavenging and may occasionally benefit from kitchen and other household wastes. Eggs and chicken meat contribute to the protein nutrition of the rural population thus alleviating malnutrition. Sales of eggs and meat earn and diversify incomes for rural households especially among women and children who control benefits accruing from the enterprise. It has also helped those affected and infected by HIV Aids because it does not involve a lot of hard work. Indigenous chicken in Kenya are about 76 % of the total poultry population and produce about 55 and 47% of the total meat and eggs respectively. Productivity is low due to factors which include genotype, poor nutrition, diseases and management. Feed supplementation, provision of housing and disease control was found to improve growth rate and egg production.

Indigenous chicken production in Kenya: a review.

Variation of carbohydrate composition of two forms of fruit from jack tree (Artocarpus heterophyllus L.) with maturity and climatic conditions

The rationale for conducting the research was to determine the optimum dietary protein and energy concentration for maximum performance of broilers housed in different environmental temperatures. Male broilers were house in temperatures ranging from 21.1°C to 35°C and fed grower diets containing either 3050 or 3250 kcal ME/kg with five different levels of CP and amino acids. The broilers fed the high energy diets across all temperatures had significantly improved feed conversions and protein utilization. A significant interaction between dietary CP and ME occurred because broilers fed the low energy diets across all temperatures did not show gains related to increasing protein levels, thus indicating that energy intake was the limiting nutrient. The maximum average weight gain occurred for broilers house at 21.1°C and the best average feed conversion was produced at 26.6°C. The reduction in weight gain, feed intake, feed conversion, protein utilization, and energy utilization, along with an increased percent body fat for broilers housed at temperatures >26.6°C and fed diets 21.6% CP indicated that protein and amino acid levels greater than NRC suggested levels do not compensate for lower feed intake.

Effect of Environmental Temperature, Dietary Protein, and Energy Levels on Broiler Performance

Comparison of the performance of nigerian indigenous chickens from three agro-ecological zones

Summary In a 5-year crossbreeding experiment, specific groups of the Nigeria Indigenous chicken (NI) from two ecological zones (i.e. Fulani, Fu; Fulani dwarf, FuD from the Northern Guinea Savanna and Yoruba, Y, from the Derived Savanna) and the German Dahlem Red normal (DR) and Dahlem Red Dwarf (DRD) were used to produce four genetic groups DR x Fu, Fu x DR, DR x Y, and FuD x DRD which were evaluated for age and weight at first egg, egg weight, percent hen-day egg production, percent laying mortality and resistance to disease. A total of 505 NI growers and 584 and 48 imported day-old DR and DRD chicks, respectively, were evaluated as parent stock. Data compilation was by DBase IV. Data were analysed using the General Linear Model (GLM) procedure of Statistical Analysis System (SAS, 1986). For all the traits evaluated, there was no significant difference (P>0.05) between NI from the three ecological zones. Therefore, pooled NI means were compared with the means for the DR and the crosses between them. Mean 280-day egg weights were 55.7, 36.8 and 42.9g, respectively, for DR, NI and the crosses while DR, NI and crosses produced 103, 70 and 83 eggs, respectively, over a period of 196 days. The DR x Fu cross had a significantly higher (P<0.05) egg weight for most of the periods studied with mean egg weight of 46.1g. The 280-day egg production of DR x Fu, (148) was significantly higher (P<0.05) than that of DR x Y and Fu x DR (119) and FuD x DRD (87). At week 40, DR x Fu females were significantly heavier (p<0.05) than all the females of the other groups while the FuD x DRD progeny had the least body weights at all the ages studied. Overall, DR x Fu and DR x Y were superior to Fu x DR and FuD x DRD for most of the traits studied. Results of the skin test using Skin response to Phytohaemagglutinin inoculation showed FuD x DRD, DR x Y and Fu x DR with values of 0.45mm, 0.36mm and 0.34mm, respectively. Inbred lines DR x DR and Y x Y gave values of 0.33 and 0.50, respectively.

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Crossbreeding Nigeria Indigenous with the Dahlem Red chickens for improved productivity and adaptability

Availability of appropriate genetics is important for the development of smallholder poultry (SHP). The biological potential of improved dual purpose chicken germplasms was evaluated in Nigeria. A total of six breeds (Fulani, FUNAAB Alpha, Kuroiler, Noiler, Sasso, and Shika-Brown) were tested on-station, in deep litter houses at two test centres (Public and private facility) for 504 days. Birds were fed ad libitum for the first 140 days after which restricted feeding was practised. Lowest and highest hatchability of eggs set was 55% (FUNAAB Alpha) and 89% (Sasso), respectively. At 140 days, male live weights were 200%–300 % higher than the local chickens (975 g) except Shika-Brown (152%) and Fulani (135%). Lowest (p < 0.05) age at first egg was 119 days for Shika-Brown and 120 days for FUNAAB Alpha and Kuroiler. Highest hen-housed egg production was 192 for Shika-Brown, and feed intake per dozen eggs was lowest (p < 0.05) for Shika-Brown (2.9 kg) and FUNAAB Alpha (2.9 kg). Mortality rate of the locally sourced breeds (Fulani, FUNAAB Alpha, Noiler, and Shika-Brown) was significantly lower (p < 0.05) than the foreign-sourced breeds (Kuroiler, Sasso) during brooding, growing and laying. Results from this study identified FUNAAB Alpha and Noiler as being more suitable for dual-purpose functions (egg and meat), while Sasso and Kuroiler (meat) and Shika-Brown (egg) were observed to be better suited for single purpose functions. These findings could guide the introduction of smallholder poultry-specific hybrid germplasms for the development of the smallholder poultry production systems in Nigeria.

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On-station performance evaluation of improved tropically adapted chicken breeds for smallholder poultry production systems in Nigeria.

This study aimed at determining chicken genotypes of choice and traits preference in chicken by smallholder farmers in Nigeria. Data were obtained from a total of 2063 farmers using structured questionnaires in five agro-ecological zones in Nigeria. Chi square (χ2) statistics was used to explore relationships between categorical variables. The mean ranks of the six genotypes and twelve traits of preference were compared using the non-parametric Kruskal–Wallis H (with Mann–Whitney U test for post hoc separation of mean ranks), Friedman, and Wilcoxon signed-rank (with Bonferroni’s adjustments) tests. Categorical principal component analysis (CATPCA) was used to assign farmers into groups. Gender distribution of farmers was found to be statistically significant (χ2 = 16.599; P ≤ 0.002) across the zones. With the exception of Shika Brown, preferences for chicken genotypes were significantly (P ≤ 0.01) influenced by agro-ecological zone. However, gender differentiated response was only significant (P ≤ 0.01) in Sasso chicken with more preference by male farmers. Overall, FUNAAB Alpha, Sasso, and Noiler chicken were ranked 1st, followed by Kuroiler (4th), Shika Brown (5th), and Fulani birds (6th), respectively. Within genotypes, within and across zones and gender, preferences for traits varied significantly (P ≤ 0.005 and P ≤ 0.01). Traits of preference for selection of chicken breeding stock tended towards body size, egg number, egg size, and meat taste. Spearman’s rank order correlation coefficients of traits of preference were significant (P ≤ 0.01) and ranged from 0.22 to 0.90. The two PCs extracted, which explained 65.3% of the variability in the dataset, were able to assign the farmers into two groups based on preference for body size of cock and hen and the other ten traits combined. The present findings may guide the choice of appropriate chicken genotypes while the traits of economic importance may be incorporated into future genetic improvement and conservation programs in Nigeria.

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Farmers' choice of genotypes and trait preferences in tropically adapted chickens in five agro-ecological zones in Nigeria.

Increasing poultry product consumption trends have attracted researchers and development practitioners to look for interventions that transform the low-input low-output-based village chicken production to a high yielding production system. However, due to the intricate nature of the production system, there is a dearth of evidence that helps design comprehensive interventions at the smallholder level. Using national-level representative data collected from 3555 village chicken producers in Ethiopia, Nigeria, and Tanzania, this study examines the technical efficiency of village chicken production and investigates the main factors that explain the level of inefficiency. We applied a stochastic frontier analysis to simultaneously quantify the level of technical efficiency and identify factors associated with heterogeneity in inefficiency. We found that the level of technical efficiency is extremely low in the three countries, suggesting enormous opportunities to enhance productivity using available resources. The heterogeneity in technical efficiency is strongly associated with producers’ experience in breed improvements and flock management, limited technical knowledge and skills, limited access to institutions and markets, smaller flock size, gender disparities, and household livelihood orientation. We argue the need to adopt an integrated approach to enhance village producers’ productivity and transform the traditional subsistence-based production system into a commercially oriented semi-intensive production system.

https://www.mdpi.com/2071-1050/13/15/8539/pdf

Emmanuel B. Sonaiya

Papers

Comparison of the performance of nigerian indigenous chickens from three agro-ecological zones

Crossbreeding Nigeria Indigenous with the Dahlem Red chickens for improved productivity and adaptability

On-station performance evaluation of improved tropically adapted chicken breeds for smallholder poultry production systems in Nigeria.

Farmers' choice of genotypes and trait preferences in tropically adapted chickens in five agro-ecological zones in Nigeria.

Technical Efficiency of Traditional Village Chicken Production in Africa: Entry Points for Sustainable Transformation and Improved Livelihood