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ABSTRACT: This study aimed to determine the impact of the age of breeder hens and egg storage on egg quality, embryonic development, hatching events and chick quality in FUNAAB-alpha chickens. The study involved the use of 500 hatching eggs each collected from 32-wk and 60-wk-old of FUNAAB-alpha broiler breeder hens at the Animal Breeding and Genetic Unit of the Federal University of Agriculture, Abeokuta, Nigeria and subjected to 5 storage periods (0, 3, 7, 11, and 15 d). The quality traits of the eggs were recorded and incubated using the conventional protocol. Data were collected on the internal and external egg characteristics, embryonic development, hatching events, and chick quality. The data collected were laid out in 2 by 5 factorial design. The results showed that eggs from 32-wk-old breeder hens had higher albumen height and Haugh unit (HU) value than those from 60-wk-old breeders. The albumen height and HU decreased progressively with storage length in the 2 age groups. Extended storage duration linearly increased (P < 0.01) egg weight loss and decreased (P < 0.01) yolk height. The eggs from both breeder ages had increasing blastodermal diameters at oviposition up until d 11 of storage but decreased on d 15 of storage in eggs from 32 wk breeders. Eggs of 32-wk-old FUNAAB-alpha breeder hens had larger diameters at oviposition compared with 60-wk-old breeders. The chicks from 60-wk breeder had late internal pipping (469.06 h), early external pipping (474.46 h) and a shorter time lag between both pips (9.00 h) compared to chicks from 32 wk breeder. The highest fertility was recorded in eggs stored for 3 d (80.7% and 79.6%), while the lowest fertility was in eggs stored for 15 d (53.4% and 47.7%) in both 32-wk and 60-wk-old breeders, respectively. Chicks from young breeder hens stored for 3 d had better quality scores (100%) compared to 0, 7, 11, and 15-d storage duration and in 60-wk-old breeders across all storage duration. It was concluded that both egg storage duration and age of breeder affected egg quality, hatching events and hatchling quality of FUNAAB-alpha chickens and the interaction effects of both factors was recorded for some of these traits. However, extended storage beyond 7 d had a larger negative impact on egg quality and hatchability of eggs from an old breeder (60 wk) than on eggs of a young breeder (32 wk).

A study was conducted to estimate the diversity that exists among three rabbit populations adapted to the South-Eastern part of Nigeria. Blood samples were collected from 75 matured, mixed-sex, and unrelated three rabbit breeds selected across the zone. Eight microsatellites (Sol30, Sol33, and Sol44, Sat3, Sat7, Sat8, Sat12, and INRA) markers were used for the study. These microsatellites were uniformly distributed among rabbit genomes for genotyping. Subsequently, genetic variability within and between breeds was calculated. Allelic frequencies and Hardy-Weinberg equilibriums as well as Analysis of Molecular Variance, were also estimated using GenAlEX 6.41 software. Discriminant Analysis of Principal Components (DAPC) for the population structure of the rabbit breeds was performed in R v.3.5.0 using the R package adegenet. All the 8 loci amplified in this study were found to be 100% polymorphic, the observed allele sizes and their frequencies for the microsatellite markers in every three breeds showed that the highest frequency was 0.330 for the allele with the size of 470bp at Sol33 locus in New Zealand White (NZW) rabbits. The Nei’s genetic identities and distances between Chinchilla (CHI) and Dutch (DUT), CHI and NZW, DUT and NZW obtained in this study were [0.173, 0.185, and 0.189] and [1.753, 1.689, and 1.666] respectively. The dendrogram and biplot revealed that the three breeds were identified at two separate clusters. In addition, the admixture level of an individual rabbit among the three breeds indicated that the breeds were not pure and also the existence of more polymorphism within the breed than among the breed diversity.

This trial was designed to evaluate the influence of hatching egg storage length and broiler breeder hens' age on post-hatch growth performance and physiological responses of FUNAAB-α chickens. Five hundred fertile eggs from each of 60 and 32-wk-old FUNAAB-α breeder hens were collected and assigned to five storage durations (0, 3, 7, 11, and 15 d). The hatching eggs were incubated using the conventional protocol. Data were collected on the growth performance and physiological responses. A 2 × 5 factorial design was used for the experiment. The results revealed that there was a decline in the final body weight in chickens from eggs of 15 and 11 d storage compared to the chickens from 7, 3, and 0 egg storage days. Chickens of 32-week-old breeder hens had higher ( P  < 0.05) mean corpuscular volume, white blood cell, heterophil, and pack cell volume values compared to 60-week-old breeder hens. Hatchlings from 60-week-old breeders had a higher liver percentage (3.0% yolk-free body weight [YFBW]) than those from 32-week-old breeders (2.8% YFBW). It was concluded that an extended storage duration of 15 d adversely affected the carcass traits and growth performance of chickens from egg storage above seven days., Competing Interests: The authors declare no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Early age thermal conditioning has been found to improve thermotolerance in birds. This study assessed the effect of perinatal thermal conditioning on serum parameters, corticosterone, free fatty acid, globulin and expression of corticotropin-releasing hormone (CRH) gene in five chicken strains; using fifty chicks per strain of Cobb 500 (C500), Ross 308 (R308), Shika Brown (SB), Normal Feathered Nigeria Indigenous (NF) and FUNAAB Alpha (FA). Twenty-five chicks per strain were conditioned at 40 ± 1 °C for 3 h on day 6. On day 10, both conditioned and unconditioned chicks were challenged acutely at 40 ± 1 °C for 15 min, without feed and water. Body weight and feed intake data were collected before and after the heat exposures. Blood samples were collected to determine serum electrolytes, metabolites and corticosterone levels. Brain tissue samples were collected from the 10-day-old conditioned and unconditioned chicks, from which RNA were extracted, synthesized into cDNA and subjected to qPCR. Serum parameters were significantly affected (p < 0.05) by strain, thermal conditioning and their interactions. Calcium and glucose concentrations were highest in NF while FA had highest in sodium. Calcium, glucose and phosphorus were higher in conditioned birds. NF had the highest free fatty acid while FA had the lowest. C500 had the highest globulin levels. Thermal conditioning significantly lowered corticosterone levels in conditioned birds. CRH was shown to be overexpressed in C500. From this research, it can be concluded that early age thermal conditioning affects body temperature regulation in chickens and enhances thermotolerance., (© 2022. The Author(s), under exclusive licence to Institute of Plant Genetics Polish Academy of Sciences.)

This study was conducted to characterise phenotypically helmeted Guinea fowls in three agro-ecologies in Nigeria using multivariate approach. Eighteen biometric characters, four morphological indices and eleven qualitative physical traits were investigated in a total of 569 adult birds (158 males and 411 females). Descriptive statistics, non-parametric Kruskal-Wallis H test followed by the Mann-Whitney U and Dunn-Bonferroni tests for post hoc, Multiple Correspondence Analysis (MCA), Univariate Analysis, Canonical Discriminant Analysis, Categorical Principal Component Analysis and Decision Trees were employed to discern the effects of agro-ecological zone and sex on the morphostructural parameters. Agro-ecology had significant effect (P<0.05; P<0.01) on all the colour traits. In general, the most frequently observed colour phenotype of Guinea fowl had pearl plumage colour (54.0%), pale red skin colour (94.2%), black shank colour (68.7%), brown eye colour (49.7%), white earlobe colour (54.8%) and brown helmet colour (72.6%). The frequencies of helmet shape and wattle size were significantly influenced (P<0.01) by agro-ecology and sex. Overall, birds from the Southern Guinea Savanna zone had significantly higher values (P<0.05) for most biometric traits compared to their Sudano-Sahelian and Tropical Rainforest counterparts. They were also more compact (120.00 vs. 110.00 vs. 107.69) but had lesser condition index (7.66 vs. 9.45 vs. 9.30) and lower long-leggedness (19.71 vs. 19.23 vs. 9.51) than their counterparts from the two other zones. Sexual dimorphism (P<0.05) was in favour of male birds especially those in Southern Guinea Savanna and Sudano-Sahelian zones. However, the MCA and discriminant analysis revealed considerable intermingling of the qualitative physical traits, biometric traits and body indices especially between the Sudano-Sahelian and Tropical Rainforest birds. In spite of the high level of genetic admixture, the Guinea fowl populations could to a relative extent be distinguished using wing length, body length and eye colour. Generally, the birds from the three zones appeared to be more homogeneous than heterogeneous in nature. However, further complementary work on genomics will guide future selection and breeding programs geared towards improving the productivity, survival and environmental adaptation of indigenous helmeted Guinea fowls in the tropics., Competing Interests: The authors have declared that no competing interests exist.

Little is known about immediate and long-lasting effect of acute heat stress on chicken cognition. Thirty-five, 9-week-old birds were trained to differentiate two cone colours; white (rewarded, R; with feed underneath) and black (unrewarded, UR; empty). The sixteen birds that learnt the task were randomly assigned to three temperature regimens (TR: 22-24 °C (control), 30-32 and 36-38 °C for 3h/day) for three consecutive days during which rectal (RT), wing (WT) and eye (ET) temperatures were monitored. After the 3 h of exposure, birds were allowed to rest for 1 h before the commencement of the discriminant task. The latencies to open the cones (R and UR) and proportion of cones opened were recorded. A long-lasting effect was tested a week after exposure to TR. TR had a significant effect on RT, WT and ET. The motivation to turn over R cones was weaker in birds exposed to 36-38 °C than birds exposed to 22-24 °C. Also, the proportion of R cones opened were fewer in birds that experienced TR of 36-38 °C compared to birds exposed to 22-24 °C and 30-32 °C specifically on two out of the three cognitive test days (Days 1 and 3). Latency and proportion of UR cones opened was not affected by TR. RT, WT and ET were all negatively and significantly correlated with latency to open the UR cones. Previous exposure of birds to three TR had no effect on the latency to open both cones but the proportion of R cones opened was greater in birds exposed to 30-32 °C compared to the 22-24 °C birds. In conclusion, an immediate (36-38 °C) and long-lasting effect (30-32 °C) of acute heat stress was associated with a weak motivation to perform feed related discrimination task., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

To date, there is no reported standard mating ratio for Nigerian native chickens despite their large population in the country. This study investigated the effect of mating ratio on behaviour, semen quality and level of stress. Sixty-three (9 cocks and 54 hens) sexually matured birds were randomly assigned to three mating ratios (MR) of 1 cock to 3 hens (1C:3H), 1 cock to 6 hens (1C:6H) and 1 cock to 9 hens (1C:9H), and each MR was replicated three times. Each cock spent 2 weeks in a particular MR before it was moved to another. By the 6th week, all cocks had experienced the three mating ratios. Behaviour of the hens and sexual behaviour of the cocks were observed in the morning and evening, respectively, for 6 weeks. At the end of 2nd week in each MR, semen samples were collected and evaluated for motility, morphology, liveability and concentration, and blood samples were also taken from the cocks to determine the heterophil/lymphocyte (H:L) ratio, an indicator of stress. There was also no significant effect of mating ratio on the fertility of eggs and hatchability of the chicks. The number of hen-hen aggression instances, frequency of visits to the nest box and duration of nesting was not influenced by the mating ratio. However, the duration of nest seeking was higher at 1C:3H and lower at 1C:9H. A mating ratio of 1C:9H is therefore recommended for farmers interested in raising Nigerian native chickens., (© 2020 Blackwell Verlag GmbH.)

The objective of this study was to characterize GnRHR gene in Sokoto (n = 70) and Kalahari Red (n = 70) goats. Three SNPs, (g.-29T > G, g.48 G > A and g.209 T > G), were detected in Sokoto Red (SR) and one (g.48 G > A) in Kalahari Red (KR) goats. All the mutations occurred within the 5'UTR and Exon one of the gene and the g.209 T > G was non-synonymous and, therefore, resulted in an amino acid change from methionine to arginine at Position 70 of the GnRHR polypeptide. The homozygous mutant genotypes at the three SNP loci were not detected in both breeds but minor allele frequencies were ≥ 0.1 for the three SNP loci in SR goats. Frequency of the T allele, however, was 0.93 at the only SNP locus detected in KR goats. There was a strong linkage disequilibrium (LD; r 2 >0.98) among the detected mutations in SR goats resulting in two haplotypes (T-G-T and G-A-G) with a frequency of 86% and 13%, respectively. There was no significant association between genotypes at the polymorphic loci and litter size (P > 0.05) in the two breeds. The non-synonymous mutation (g.209T>G) appears to have changed the nucleotide binding region and area spanning exposed/buried regions on the predicted secondary structure of the two variants of the receptor. This change led to variation in the tertiary structure between the two variants of the receptor and can influence the function of the transmembrane receptor. Comparison of the GnRH receptor domains for goats, sheep, cattle and swine confirmed that the seven transmembrane domains of the receptor are conserved in all the farm animals considered., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)

The expression of four genes involved in milk regulation and production in bovine milk and tissue samples profiled using quantitative PCR to identify differential gene expression. Our goal focussed on the differential mRNA expression of milk genes ( KCN , PRL , BLG and PIT-1 ) in milk samples and different tissues from four different breeds of ecologically adapted and geographically separated cattle species. The mRNA expression identified the four milk genes under studied most upregulated in mammary gland and milk samples as compared with other tissues. The expression of PIT-1 gene in the brain identified to have influenced the expression of PRL and K-CN in the mammary and milk samples. Among the four genes, PRL had the highest mRNA expression (144.19-fold change) in Holstein followed by K-CN with 100.89-fold change, while the smallest relative expression for most genes in this study are in the range from 0.79 to 7.35-fold difference. White Fulani cattle was identified to have a higher expression for K-CN , PRL and BLG compared with Angus and Ndama cattle, while Holstein cattle is on top of the list on the basis of the gene expression and gene regulation for all the four genes in this study. Also, White Fulani and Holstein are in the same cluster based on their mRNA expression for milk genes. Our data showed the first evidence of the molecular identification of indigenous White Fulani cattle ofhaving potential for higher milk production.

Gonadotropin-releasing hormone receptor (GnRHR) gene is considered a candidate gene for litter size due to its critical role in regulating the activities of hypothalamo-pituitary-gonadal axis which synthesizes and releases gonadotropins. This study was designed to identify mutations within the caprine GnRHR gene and investigate their association with litter size at various parities. Polymorphisms scanning and genotyping of GnRHR gene in West African Dwarf (WAD) goats (n = 226) revealed three single nucleotide polymorphisms (SNPs), one mutation (g.-29T > G) was detected within 5'UTR region while two others (g.48G > A and g.209T > G) were identified in exon 1. Mutation at g.209T > G locus resulted in amino acid change from Methionine to Arginine at position 70 on the polypeptide residue. Based on heterozygosity and polymorphism information content (PIC), WAD goat population diversity at the SNP loci was moderate. Strong linkage disequilibrium (LD) (r 2  > 0.98) existed among the detected mutations resulting in three observed haplotypes, two (T-G-T and G-A-G) had cumulative frequency of > 97%. The mutation within 5'UTR region of GnRHR gene (g.-29T > G) is novel, being reported in goats for the first time. Association analysis revealed a significant (p < 0.05) association between allele G at g.-29T > G with higher mean litter size for homozygous (GG) mutant does compared with heterozygotes (GT) or homozygotes (TT), while the relationship between SNPs at the two loci detected in exon 1 and litter size was not significant.

Trypanosoma vivax (sub-genus Duttonella) is largely responsible for non profitable livestock production in sub-Sahara Africa. In Nigeria, no study has addressed the molecular characteristic of T. vivax except Y486. Hence, we characterized and assessed the genetic diversity among T. vivax detected in naturally infected cattle in Nigeria using internal transcribed spacer 1 (ITS1) of ribosoma DNA (rDNA) and diagnostic antigen gene (DAG) sequences. The length of ITS1 and DAG sequences range from 215-220 to 257-338 bp, respectively and the mean G-C contents were 60 and 61.5 %. Homology search revealed 93-99 and 95-100 % homologies to T. vivax DAG and ITS1 sequences from GenBank. Aligned sequences revealed both ITS1 rDNA and DAG to be less polymorphic but DAG sequences of the Y486 strain and its clone showed marked variation from autochthonous strains. Phylogenetic analysis yielded tree that grouped T. vivax ITS1rDNA gene and DAG sequences into two main clades each. Considering the ITI1 rDNA sequences, clade A contained autochthonous T. vivax within which the South American sequences clustered, clade B contained the sequences of T. vivax from East Africa. Analysis of DAG revealed that the clade A contains autochthonous T. vivax sequences but clade B contained the Y486 and its clones. In conclusion, the diagnostic antigen gene sequences of the T. vivax detected in this study may have undergone considerable gene recombination through time and suggests that more than one strain of T. vivax exist among cattle population in Nigeria.

Host defense in vertebrates depend on many secreted regulatory proteins such as major histocompatibility complex (MHC) class II which provide important regulatory and effector functions of T cells. Gene polymorphism in the second exon of Capra-DRB gene in three major Nigerian goat breeds [West African Dwarf (WAD), Red Sokoto (RS), and Sahel (SH)] was analyzed by restriction fragment length polymorphisms (RFLP). Four restriction enzymes, BsaHI, AluI, HaeIII, and SacII, were utilized. The association between the polymorphic sites and some heat tolerance traits were also investigated in a total of 70 WAD, 90 RS, and 50 SH goats. Fourteen different types of alleles identified in the Nigerian goats, four of which were found in the peptide coding region (A57G, Q89R, G104D, and T112I), indicate a high degree of polymorphism at the DRB locus in this species. An obvious excess (P < 0.01) of non-synonymous substitutions than synonymous (dN/dS) in this locus is a reflection of adaptive evolution and positive selection. The phylogenetic trees revealed largely species-wise clustering in DRB gene. BsaHI, AluI, HaeIII, and SacII genotype frequencies were in Hardy-Weinberg equilibrium (P > 0.05), except AluI in RS goats and HaeIII in WAD goats (P < 0.05). The expected heterozygosity (H), which is a measure of gene diversity in the goat populations, ranged from 0.16 to 0.50. Genotypes AA (BsaHI), GG, GC and CC (AluI) and GG, GA, AA (HaeIII) appeared better in terms of heat tolerance. The heat-tolerant ability of SH and RS goats to the hot and humid tropical environment of Nigeria seemed better than that of the WAD goats. Sex effect (P < 0.05) was mainly on pulse rate and heat stress index, while there were varying interaction effects on heat tolerance. Variation at the DRB locus may prove to be important in possible selection and breeding for genetic resistance to heat stress in the tropics.

In continuing efforts to better understand the genetics of bovine trypanosomosis, we assessed genetic diversity of Trypanosoma brucei and Trypanosoma evansi in naturally infected Nigerian cattle using repetitive DNA and internal transcribed spacer 1 of rDNA sequences and compared these sequences to species from other countries. The length of repetitive DNA sequences in both species ranged from 161 to 244 bp and 239 to 240 bp for T. brucei and T. evansi, respectively, while the ITS1 rDNA sequences length range from 299 to 364 bp. The mean GC content of ITS1 rDNA sequences was 33.57 %, and that of repetitive sequences were 39.9 and 31.1 % for T. brucei and T. evansi, respectively. Result from sequence alignment revealed both T. brucei and T. evansi repetitive DNA sequences to be more polymorphic than ITS1 rDNA sequences, with moderate points of deletion and insertions. T. brucei separated into two clades when subjected to phylogenetic analysis. T. evansi repetitive DNA sequences clustered tightly within the T. brucei clade while the ITS1 rDNA sequences of T. brucei were clearly separated from T. theileri and T. vivax individually used as outgroups. This study suggest that ITS1 rDNA sequences may not be suitable for phylogenetic differentiation of the Trypanozoon group and also suggest that T. evansi may be a phenotypic variant of T. brucei which may have potential implications in designing prevention and therapeutic strategies.

This study was conducted to evaluate the variation in antibody from Newcastle disease (ND) vaccinated breeder birds and their progenies. The chicks were evaluated for maternally derived antibody (MDA) against ND virus and also the MDA transfer rate for each genotype. The local parent stocks were Frizzle-feathered, Normal-feathered, and Naked neck while an exotic parent stock (Anak Titan) was used for the purpose of comparison. Sera samples were collected from chicks generated at day 3 post-hatch, and sera were also collected from the parent stocks. The sera samples were stored at -20 °C until analysed. Enzyme linked immuno-sorbent assay (ELISA) test was used for the detection and quantification of antibodies to ND in the parent stocks and the chicks using IDEXX Newcastle Disease ELISA test kit. The least squares means of antibody titers for parent stocks were 413.333 ± 68.853, 426.333 ± 121.949, 481.667 ± 145.454, and 1148.333 ± 532.843 for Frizzle-feathered, Normal-feathered, Naked Neck, and Anak Titan, and the calculated MDA transfer rate was 96.4, 93.8, 88.7, and 34.7 % for Frizzle-feathered, Normal-feathered, Naked neck, and Anak Titan, respectively. The mean antibody titers for chicks were 398.6 ± 43.871, 400.0 ± 53.952, 427.0 ± 89.353, and 398.8 ± 57.593 for Frizzle-feathered, Normal-feathered, Naked neck, and Anak Titan, respectively. The antibody titers from parent stocks were higher than those observed in chicks for all the genotypes. The values obtained in this study indicated that parent stocks with their progenies were below protective level. The local parent stocks had higher transfer rate when compared to their exotic counterpart. Hence, there is an indication from this finding that the local chickens had a better transfer rate in relation to Anak Titan which is an exotic breed. Therefore, there is the presence of genetic variability for antibody transfer in the Nigerian local chickens and can be incorporated in designing a breeding program for better adaptive potential.

The tenascin-XB (TNXB) gene has antiadhesive effects, functions in matrix maturation in connective tissues, and localizes to the major histocompatibility complex class III region. We hypothesized that it may influence adaptive physiological response through an effect on blood vessel function. We identified a novel g.1324 A→G polymorphism at a TaqI recognition site in a 454 bp fragment of ovine TNXB and genotyped it in 150 Nigerian sheep using PCR-RFLP. The missense mutation changes glutamic acid (GAA) to glycine (GGA). Among SNP genotypes, significant differences (P < 0.05) were observed in body weight and fore cannon bone length. Interaction effects of breed, SNP genotype, and geographic location had a significant effect (P < 0.05) on chest girth. The SNP genotype was significantly (P < 0.05) associated with physiological traits of pulse rate and skin temperature. The observed effect of this novel polymorphism may be mediated through its role in connective tissue biology, requiring further association and functional studies.

The DQB1 locus is located in the major histocompatibility complex (MHC) class II region and involved in immune response. We identified 20 polymorphic sites in a 228 bp fragment of exon 2, one of the most critical regions of the MHC DQB1 gene, in 60 Nigerian goats. Four sites are located in the peptide binding region, and 10 amino acid substitutions are peculiar to Nigerian goats, compared with published sequences. A significantly higher ratio of nonsynonymous/synonymous substitutions (dN/dS) suggests that allelic sequence evolution is driven by balancing selection (P < 0.01). In silico functional analysis using PANTHER predicted that substitution P56R, with a subPSEC score of -4.00629 (Pdeleterious = 0.73229), is harmful to protein function. The phylogenetic tree from consensus sequences placed the two northern breeds closer to each other than either was to the southern goats. This first report of sequence diversity at the DQB1 locus for any African goat breed may be useful in the search for disease-resistant genotypes.

The agouti-signaling protein (ASIP) plays a major role in mammalian pigmentation as an antagonist to melanocortin-1 receptor gene to stimulate pheomelanin synthesis, a major pigment conferring mammalian coat color. We sequenced a 352 bp fragment of ASIP gene spanning part of exon 2 and part of intron 2 in 215 animals representing six goat breeds from Nigeria and the United States: West African Dwarf, predominantly black; Red Sokoto, mostly red; and Sahel, mostly white from Nigeria; black and white Alpine, brown and white Spanish and white Saanen from the US. Twenty haplotypes from nine mutations representing three intronic, one silent and five missense (p.S19R, p.N35K, p.L36V, p.M42L and p.L45W) mutations were identified in Nigerian goats. Approximately 89 % of Nigerian goats carry haplotype 1 (TGCCATCCG) which seems to be the wild type configuration of mutations in this region of the gene. Although we found no association between these polymorphisms in the ASIP gene and coat color in Nigerian goats, in-silico functional analysis predicts putative deleterious functional impact of the p.L45W mutation on the basic amino-terminal domain of ASIP. In the American goats, two intronic mutations, g.293G>A and g.327C>A, were identified in the Alpine breed, although the g.293G>A mutation is common to American and Nigerian goat populations. All Sannen and Sahel goats in this study belong to haplotypes 1 of both populations which seem to be the wild-type composite ASIP haplotype. Overall, there was no clear association of this portion of the ASIP gene interrogated in this study with coat color variation. Therefore, additional genomic analyses of promoter sequence, the entire coding and non-coding regions of the ASIP gene will be required to obtain a definite conclusion.

Microscopy and polymerase chain reaction (PCR) were used to survey pathogenic trypanosome infection in naturally infected Nigerian cattle. In 411 animals sampled, microscopy detected 15.1% positive infection of at least one of Trypanosoma brucei, Trypanosoma congolense or Trypanosoma vivax, while PCR detected 63.7% positive infections of at least one of those species and Trypanosoma evansi. PCR detected 4.4%, 48.7%, 26.0% and 0.5% respectively of T. brucei, T. congolense, T. vivax and T. evansi infections. All of the T. congolense detected were savannah-type, except for two forest-type infections. Prevalence of mixed infections was 13.9%, being primarily co-infection by T. congolense and T. vivax while prevalence of mixed infections by T. evansi, T. vivax and T. congolense was 1.5%. Microscopy showed poor sensitivity but specificity greater than 94%. Infection rates were much higher in Southern than in Northern Nigeria. Infections were lowest in N'dama compared to Muturu, Sokoto Gudali and White Fulani breeds. Animals with T. vivax monoinfection and mixed infections showed significantly lower packed cell volume (PCV) values. Those infected with any Trypanosoma species with <200 parasites/μl showed higher PCV values than those infected with >200 parasites/μl. The new finding of savannah- and forest-type T. congolense in Nigeria and the relatively high abundance of mixed infections are of significant clinical relevance. This study also suggests that T. congolense is the most prevalent species in Nigeria., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Background: Sheep 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., Results: Morphological 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., Conclusions: These 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.