Olufunmilayo A. Adebambo

Morphological and microsatellite DNA diversity of Nigerian indigenous sheep

BackgroundSheep is important in the socio-economic lives of people around the world. It is estimated that more than half of our once common livestock breeds are now endangered. Since genetic characterization of Nigerian sheep is still lacking, we analyzed ten morphological traits on 402 animals and 15 microsatellite DNA markers in 384 animals of the 4 Nigerian sheep breeds to better understand genetic diversity for breeding management and germplasm conservation.ResultsMorphological traits of Uda and Balami were significantly (P < 0.05) higher than Yankasa, which were both higher than West African Dwarf (WAD) sheep. Stepwise discriminant analysis showed tail length, rump height, chest girth, ear length and chest depth as the most discriminating variables for classification. Mahalanobis distances show the least differentiation between Uda and Balami and the largest between WAD and Balami sheep. While 93.3% of WAD sheep were correctly assigned to their source genetic group, 63.9% of Yankasa, 61.2% of Balami and 45.2% of Uda were classified correctly by nearest neighbour discriminant analysis. The overall high Polymorphism Information Content (PIC) of all microsatellite markers ranged from 0.751 to 0.927 supporting their use in genetic characterization. Expected heterozygosity was high for all loci (0.783 to 0.93). Mean heterozygote deficiency across all populations (0.171 to 0.534) possibly indicate significant inbreeding (P < 0.05). Mean values for FST, FIT and FIS statistics across all loci were 0.088, 0.394 and 0.336 respectively. Yankasa and Balami are the most closely related breeds (DA = 0.184) while WAD and Balami are the farthest apart breeds (DA = 0.665), which is coincident with distance based on morphological analysis and population structure assessed by STRUCTURE.ConclusionsThese results suggest that within-breed genetic variation in Nigerian sheep is higher than between-breeds and may be a valuable tool for genetic improvement and conservation. The higher genetic variability in Yankasa suggests the presence of unique ancestral alleles reflecting the presence of certain functional genes which may result in better adaptability in more agro-ecological zones of Nigeria. These genetic characteristics are potentially useful in planning improvement and conservation strategies in Nigerian indigenous sheep.

A preliminary screening of genetic lineage of nigerian local chickens based on blood protein polymorphisms

Fueron tomadas muestras de sangre para el analisis proteico en tres variedades de gallinas autoctonas nigerianas (de plumaje normal, de plumaje rizado y de cuello desnudo) y una variedad exotica (Anak Titan). Cada una de estas poblaciones representa un genotipo. Se usaron muestras de sangre de 50 animales por genotipo para valorar la diversidad genetica de las gallinas autoctonas nigerianas. Fueron observados un total de 18 grupos a partir de las cuatro variedades durante la resolucion de la proteina utilizando electroforesis en gel de poliacrilamida con dodecilsulfato sodico (pagina de SDS). El dendograma desarrollado desde los diferentes grupos observados revelo que las variedades se encontraban claramente separadas unas de otras y con una semejanza genetica media entre las cuatro variedades del 55 percent, siendo la variedad de cuello desnudo las mas separada.

Application of principal component and discriminant analyses to morpho-structural indices of indigenous and exotic chickens raised under intensive management system.

The objectives of this study were to investigate the relationships between body weight and morpho-structural indices to predict body weight from their orthogonal body shape characters using principal component analysis and to morphologically classify the chicken genotypes using multivariate discriminant analysis. Data used were from 273 randomly selected 12-weeks-old indigenous chickens of normal-feathered (NF), frizzle-feathered (FF), naked-neck (NN) and Anak Titan (AT) genotypes. Phenotypic correlation among body weight and most biometric traits ranged from 0.227–0.876, −0.7–0.901, 0.034–0.968 and −0.207–0.849 for NF, NN and AT chickens, respectively. Factor analysis with varimax rotation of interrelated traits revealed three principal components which accounted for 83.1%, 74.4%, 78.8% and 76.5% of the total variance in NF, FF, NN and AT chickens in the order listed. Breast girth, keel length, thigh length, shank length and wing length were found to be the most discriminating variables to separate the chicken genotypes. The longest distance (72.54) occurred between AT and NF genotypes while the shortest distance (4.27) was recorded for FF and NN genotypes. Classification results showed that 85.2% of AT genotype was correctly classified into their source population. However, 22.7% of NF was misclassified as NN, while 33.3% of NN was misclassified as NF chickens. These results suggest that there is high rate of gene flow between these two indigenous chicken genotypes. Information obtained from this study may be considered useful in breed improvement programmes for selection, characterization, conservation and better management of Nigerian indigenous chickens.

Genetic diversity analysis of the mitochondrial D-loop of Nigerian indigenous sheep

Los recursos ganaderos autoctonos son de caracter estrategico en los aspectos socioeconomicos de los sistemas agricolas para garantizar la seguridad alimentaria en los paises de escasos recursos. Por lo tanto, conocer mejor la importancia de la variabilidad genetica es vital para su futura utilizacion, por medio de la conservacion. Se presenta el primer analisis de la diversidad genetica en ovejas de Nigeria basado en la region de control (D-loop) del Ovis aries del genoma mitocondrial, utilizando 1.179 bases entre las posiciones 15.437 y 16.616 de pares de bases. Una muestra de 290 animales, compuesta por las razas Balami, West African Dwarf (WAD), Uda y Yankasa, fue tomada al azar de toda Nigeria. Se observaron noventa y seis (96) haplotipos, con una alta diversidad media en cuanto a estos de 0,899 ± 0,148. La diversidad genetica fue mayor en la raza Uda (0,921 ± 0,021) y menor en la raza WAD (0,852 ± 0,061). Los indices de poblacion especificos FST variaron de 0.00133 en la raza Uda a 0,00335 en la razaWAD. La raza Yankasa presento el mayor numero de posiciones polimorficas (201), mientras que el menor lo mostro la raza Uda (96). Analisis de la varianza molecular revelo que 0,23% de la variacion se encuentra entre las poblaciones, en comparacion con el 99,77% de variacion que se encuentra dentro de las poblaciones. El arbol filogenetico indica que los linajes mitocondriales de las razas ovinas partieron de un origen comun en conformidad con la primera divergencia de la raza Yankasa, seguida por WAD, mientras que las razas Balami y Uda se encuentran mas estrechamente relacionadas. Estos resultados demuestran que la divergencia evolutiva de las poblaciones ovinas de Nigeria, basados en el ADN mitocondrial de la region control, puede coincidir con la distribucion geografica en Nigeria e indican una tasa importante de cruzamiento entre ellas. Esto podria tener ventajas desde el punto de vista de la gestion de la mejora y las estrategias de conservacion y preservacion a largo plazo de las ovejas autoctonas de Nigeria.

Multifactorial discriminant analysis of morphological and heat-tolerant traits in indigenous, exotic and cross-bred turkeys in Nigeria.

Este estudio examina la capacidad para distinguir los rasgos morfologicos y de tolerancia al calor en pavos autoctonos, exoticos y cruzados en Nigeria mediante el analisis discriminante multivariado. Un total de 228 pavos de 20 semanas de edad fueron utilizados en el estudio. Los parametros corporales medidos fueron el peso corporal (BW), diametro longitudinal (BL), longitud del tarso (SL), longitud del muslo (TL), longitud de quilla (KL), perimetro toracico (BG), temperatura rectal (RT), frecuencia del pulso (PR), frecuencia respiratoria (FR) y el indice de estres termico (HI). El analisis de la varianza revelo que los pavos exoticos mostraban valores significativamente ( p < 0,05) mayores que los pavos autoctonos de Nigeria y que los cruzados para todos los rasgos morfologicos, con la excepcion de la TL. Sin embargo, los pavos autoctonos y los cruzados parecian tener mas capacidad de adaptacion que los exoticos en base a valores de HI mas bajos. El dimorfismo sexual se observo solo en los caracteres morfologicos, donde los machos presentaron de forma significativa ( p < 0,05) un mayor BW, BL, SL, TL y KL que en las hembras. Sin embargo, el analisis discriminante por pasos revelo que BW, TL y HI, fueron las variables mas discriminantes a la hora de separar los tres grupos geneticos. La mayor distancia de Mahalanobis se observo entre los pavos autoctonos y exoticos (36,68), mientras que la distancia mas corta se registro entre los pavos autoctonos y los cruzados (7,97). El diagrama canonico puso de manifiesto la heterogeneidad de las poblaciones de pavo, agrupando las aves por separado. En el nivel de asignacion mas cercano del analisis discriminante, el 100,00%, el 98,73%y el 96,43%de pavos exoticos, cruzados y autoctonos fueron asignados correctamente en sus grupos de origen genetico. Los presentes hallazgos podrian ayudar a la implementacion de una estrategia de conservacion y mejora de los pavos autoctonos hacia el desarrollo sostenible de los recursos zoogeneticos.

Effect of crossbreeding on fertility, hatchability and embryonic mortality of Nigerian local chickens

A total of 970 eggs were collected from matings involving three genotypes of Nigerian local chickens (Normal-feathered, Frizzle-feathered and Naked neck) and one exotic broiler breeder strain (Anak Titan) to evaluate the effect of crossbreeding on fertility, hatchability and embryonic mortality. Mating was achieved through artificial insemination. Sire genotype significantly (P < 0.05) affected percent fertility and percent dead-in-shell. Naked neck sire genotype had the highest dead-in-shell (19.5%) with the least being 7.5% for Frizzle-feathered chickens. Frizzle-feathered sire genotype had the highest fertility (90.5%) and hatchability (91.4%). Dam genotype had a significant effect (P < 0.01) on fertility and hatchability, with Anak Titan dam having the highest fertility and hatchability of 88.2% and 94.6%, respectively. Fertility and hatchability were significantly (P < 0.05) influenced by the interactive effect of sire and dam genotypes with Frizzle-feathered × Anak Titan having 98.5% fertility and 96.8% hatchability. Both straight and reciprocal crosses involving Frizzle-feathered genotype and Anak Titan resulted in higher mean values for fertility and hatchability when compared to crosses involving the other two local chicken genotypes. This result suggests that the use of the Frizzle-feathered genotype appears to be more desirable in fertility and hatchability trials.

Physiological adaptation of local, exotic and crossbred turkeys to the hot and humid tropical environment of Nigeria

Abstract A total of 300 birds consisting of 120 local, 120 crossbred and 60 exotic turkeys were used to compare physiological adaptation of birds raised under the high-heat stress environment of Nigerian tropical humid climate. Genotype significantly (P<0.05) affected heat tolerance traits with the highest mean values for rectal temperature, pulse-rate and heat stress index observed in exotic turkeys. Genotype also had significant (P<0.05) effect on serum biochemical parameters such as glucose (GLU), potassium (K+) and Chloride (Cl–). The haematological indices of the birds such as haemoglobin, white blood cell count and heterophyl/lymphocyte ratio (H/L) were equally affected by the different genetic groups (P < 0.05). The significantly higher (P<0.05) H/L ratio of the exotic turkeys was an indication of heat stress. The better performance exhibited by local and crossbred turkeys could be exploited in management, conservation and selection decisions of animal genetic resources under tropical conditions.

The Muturu: A rare sacred breed of cattle in Nigeria

The Muturu, a trypanotolerant cattle breed is probably one of the least known breed of cattle in West Africa. Little has been published on its distribution, management, morphological characteristics or biological performance. Early reports showed that the Muturu cattle were once widely distributed across the continent from Liberia, across the West African subregion, to Ethiopia. However, due to expansion of the Zebu population and rapid urbanization, the small bodied animal came under pressure and was found surviving in pockets of the savannahs and in the humid forest zones where it had the comparative advantage of trypanotolerance. The survival of the cattle in the humid and forest zones of Nigeria stems from the fact that the animal is still sacred in so many communities and its milk is widely used for medicinal purposes. In some states of Nigeria, the semi-feral Muturu are not tended but hunted when required for sacrifice. From a population size of 0.4 million heads in 1960, Akinwunmi and Ikpi, (1985) reported a decline in the population of the breed to 50–80 thousand in the late 1980s in Nigeria although RIMS (1992), reported a population growth to 115 172 heads. With limited data bank information on their adaptation and productivity, possible identification of genes that confer resistance to or tolerance of environmental stress in these animals will be of global significance.

Interrelationship studies between heat stress traits, blood andserum biochemical indices of extensively managed Nigerian Sheep

The exposure of sheep to elevated ambient temperatures induces an increase in the dissipation of excess body heat, in order to overcome this excessive environmental heat load. Dissipation of excess body heat is emitted by evaporation of water from the respiratory tract and skin surface via panting and sweating.The following heat stress traits were measured; body temperature, rectal temperature, pulse rate and respiratory rate after the sunrise and before the sunset. While blood and serum biochemical indices measured were blood glucose, total serum protein, globulin, cholesterol and triglycerides. No significant relationship(P>0.05) was recorded between heat stress traits and blood biochemical indices studied. However, we observed a positively significant (P<0.01) relationship betweenblood and serum biochemical indices studied. Similarly, a positively significant (P<0.01) relationship was observed between heat stress traits examined.