Characterization of the cecal microbiome composition of Nigerian indigenous chickens.

Poultry cecum microbes are dynamic and complex. They play important roles in disease prevention, detoxification of harmful substances, nutrient processing, and ingestion harvesting. It may be possible to increase poultry productivity by better understanding and controlling the microbial population. We analyzed the composition and function of Nigerian hens' cecal microbiota using high-throughput sequencing methods. Using high-throughput sequencing of the 16S rRNA genes (V1-V9) hypervariable regions, the cecal microbiota of three Nigerian indigenous chicken genotypes (Naked neck, Frizzle, and Normal feather) was described and compared. A total of two phyla were represented among the three genotypes (Firmicutes and Proteobacteria). Microbiological diversity was found in the community, with naked neck having the most evenness, followed by normal feather, which had the least. There were a lot of similarities between the naked neck and frizzle feather chicken groups when it came to genetic diversity between them. For example, the bacterial cecal microbiota of the naked neck chickens was more diverse, with a higher concentration of motility proteins, two-component systems, bacterial secretion systems, and the formation and breakdown of secondary metabolites. More understanding on gut microbiota roles and interactions will help Nigerian poultry farmers improve their methods and give valuable data for the study of bacteria in the chicken gut.

Contribution of social genetic effects in variance components estimation for body weight in Nigerian indigenous chickens raised in a tropical humid location.

Social interactions among chickens can have a great unfavourable effect on economic returns in a poultry farm. The purpose of this study was to use four models to examine the influence of social genetic influences on the variation in body weight of Nigerian indigenous chickens. Sex was treated as the fixed effect within the models. Direct additive genetic, social genetic, and family effects and covariance between direct and social genetic effects were used as random effects. Data were analysed using single-trait animal models which include or exclude social genetic effects. Model comparison revealed that inclusion of full-sib family effect in model 3 did not cause any change in residual and additive genetic variances relative to estimates obtained with model 2. In general, social genetic variance was lower than the estimate for additive genetic variance, but substantially added to the overall heritable variance. For direct hereditary, full-sib family, and residual effects, accounting for heritable social effect in model 4 had a marginal effect on the size of the variances measured. All the estimated residual, additive genetic, social genetic effect, and family variances increased in comparison with model 3. The relationship between direct and social additive effects was positive and not significantly different from 0 (P > 0.05), suggesting autonomy between the direct and social breeding values. In conclusion, the use of models that account for direct effect and social genetic effect of the individual on its group members would entail an optimal individual selection scheme to increase the body weight of chickens.

Genetic polymorphisms in part of intron 7 and exon 8 of HSP90AA1 gene and its association with heat tolerance traits in two exotic layer chicken strains.

Chickens, like other vertebrates, react to stress conditions through their cultured cells by expressing heat shock proteins (HSPs). Genetic association of single-nucleotide polymorphisms (SNPs) in HSPs with desirable traits will reveal their importance as potential genetic markers. Blood samples were collected from 50 birds per strain for DNA extraction, polymerase chain reaction amplification and sequencing of the HSP90AA1 gene. SNPs were detected using Codoncode Aligner. Association of each SNP with heat tolerance traits was analysed using generalized linear model procedure of SAS. A total of seven SNPs were detected, four SNPs; A7T, A160T, T223A and C134T were detected in part of intron 7 to exon 8 of HSP90AA1 gene of BRD while three A160T, T223A and C134T were detected in HYL. SNPC134T, a synonymous variant, was detected in exon 8. Only SNPA7T was in Hardy-Weinberg equilibrium (X2 = 0.03) but had no association with the traits measured. Polymorphic information content calculated showed SNPA160T to be moderately polymorphic; other SNPs were lowly polymorphic. Heterozygosity for SNPs-A160T and T223A of BRD showed moderate genetic variation while the other SNPs and those in HYL recorded low genetic variation. The study concluded that the SNPs detected were majorly lowly polymorphic and also the SNP locus A7T in intron 7 of HSP90AA1 of BRD had no genetic association with heat tolerance traits.

Use of discriminant analysis for the evaluation of coccidiosis resistance parameters in chickens raised in hot humid tropical environment.

Coccidiosis endemicity remains a major challenge in poultry production in the tropics and all over the world. In order to develop predictive tool for identification of chickens that are at risk of coccidiosis among Nigerian indigenous chickens, body weight gain (BWG) and hematological variables were determined for chickens infected with Eimeria tenella (female = 60, male = 63) and uninfected (female = 51, male = 45). The hematological variables analyzed include the following: packed cell volume (PCV, %), white blood cells (WBC, × 106/µl), and red blood cells (RBC, × 106/µl), as well as differential leucocyte percentages of neutrophils, lymphocytes, monocytes, and eosinophils. Body weight gain was determined at days 3, 6, 9, 12, and 15. Of the 12 variables analyzed, BWG at day 3, monocyte, PCV, and WBC in males and BWG at days 6, 9, and 12, PCV, and WBC in female chickens showed significant (P ≤ 0.01) difference between the infected and uninfected. Stepwise discriminant analysis evolved a model that could distinguish uninfected from Eimeria-infected chickens. Packed cell volume, WBC, BWG at day 3, and lymphocytes emerged the most discriminant between uninfected and Eimeria-infected chickens in male chickens. In female chickens, PCV, RBC, and BWG at day 3 were identified as most discriminant variables in separating the uninfected from Eimeria-infected chickens. Therefore, this study suggests that routine blood test and estimates of body weight gain could serve as a useful tool for identifying chickens that may be at risk of coccidiosis, enabling improvement of preventive measures.

Genetic differences in the body weight and haematological traits of Nigerian indigenous chickens infected with Eimeria tenella.

In an effort to shed more light on the tolerance of indigenous chickens to coccidiosis, we compared the body weight, faecal oocyst load and haematological parameters based on sex and genotypes of Eimeria tenella-infected chickens. Three hundred chicks from three genotypes (normal-feathered, frizzle-feathered and naked-neck) of Nigerian indigenous chickens which comprised 100 birds per genotype were raised for 6 weeks. At 3 weeks old, each chick was weighed and faecal, and blood samples were collected before inoculation. Subsequently, the birds were weighed and faecal samples collected at days 1, 3, 6, 9, 12 and 15 post-inoculation. Blood samples were collected from 50 chicks per genotype at 3 and 5 weeks post-inoculation. Blood parameters were determined and faecal samples subjected to McMaster egg counting technique. Results showed genotype, and sex had significant effects on body weight from day 1 to 15 post-inoculation. Normal-feathered chicks had the highest body weight while frizzle-feathered chicks showed lowest body weight at post-inoculation. E. tenella was identified in caecal and lower intestinal mucosa of the genotypes, but genotype had no significant effect (p > 0.05) on the lesion score. There were no significant differences in haematological values among genotypes (p > 0.05) except for lymphocytes where naked-neck chicks had the highest lymphocytes' count (1.83 ± 0.02 %), followed by normal-feathered (1.79 ± 0.02 %) and the frizzle-feathered (1.68 ± 0.02 %). The present values of body weight, faecal oocyst and haematological parameters obtained seemed not to be convincing enough to suggest that the genotypes were different in terms of tolerance to coccidiosis.

Growth performance of Nigerian local chickens in crosses involving an exotic broiler breeder.

Six-hundred-and-seven-day-old chicks were generated from Nigerian local chickens consisting of three genotypes (Normal-feathered; Frizzled-feathered; Naked neck) and an exotic broiler breeder (Anak Titan) to evaluate growth performance for possible meat-type chicken development. Growth parameters measured were body weight, breast girth and keel length on weekly basis for 20 weeks. Effects of sire, dam and chick genotypes were significant (P<0.001) on growth traits. At week 20, chickens sired by the Anak Titan weighed 1,614.82 g followed by Normal-feathered local chickens with body weight of 1,211.32 g. Progenies of Anak Titan and Naked neck dams weighed 1,761.96 and 1,292.80 g at week 20, respectively. Among purebreds, Anak Titan weighed 35.05 g at day-old and had heaviest body weight of 2,360.29 g at 20 weeks compared to the three local strains. The average body weights for the crossbred, Normal-feathered × Anak Titan at day-old and week 20 were 36.39 and 1,577.63 g, respectively. This was followed by Anak Titan × Naked neck with 33.32 g at day-old and 1,514.14 g at week 20. Sex had significant effect (P<0.05) at weeks 16 and 20 with the males having higher mean values than their female counterparts. This study revealed that crosses involving Anak Titan sire × Naked neck dam had highest growth performance, and there was no strain differences among the growth performance of purebred Nigerian local chickens.

Quantitative trait loci affecting fatness in the chicken.

An F2 chicken population of 442 individuals from 30 families, obtained by crossing a broiler line with a layer line, was used for detecting and mapping Quantitative Trait Loci (QTL) affecting abdominal fat weight, skin fat weight and fat distribution. Within-family regression analyses using 102 microsatellite markers in 27 linkage groups were carried out with genome-wide significance thresholds. The QTL for abdominal fat weight were found on chromosomes 3, 7, 15 and 28; abdominal fat weight adjusted for carcass weight on chromosomes 1, 5, 7 and 28; skin and subcutaneous fat on chromosomes 3, 7 and 13; skin fat weight adjusted for carcass weight on chromosomes 3 and 28; and skin fat weight adjusted for abdominal fat weight on chromosomes 5, 7 and 15. Interactions of the QTL with sex or family were unimportant and, for each trait, there was no evidence for imprinting or of multiple QTL on any chromosome. Significant dominance effects were obtained for all but one of the significant locations for QTL affecting the weight of abdominal fat, none for skin fat and one of the three QTL affecting fat distribution. The magnitude of each QTL ranged from 3.0 to 5.2% of the residual phenotypic variation or 0.2-0.8 phenotypic standard deviations. The largest additive QTL (on chromosome 7) accounted for more than 20% of the mean weight of abdominal fat. Significant positive and negative QTL were identified from both lines.

Mapping of quantitative trait loci for body weight at three, six, and nine weeks of age in a broiler layer cross.

An F2 chicken population was established from a cross of a broiler sire-line and an egg laying (White Leghorn) line. There were two males and two females from both lines in the base population. The F1 progeny consisted of 8 males and 32 females. Over 500 F2 offspring from five hatches were reared to slaughter at a live weight of 2 kg at 9 wk of age. Body weights at 3, 6, and 9 wk were recorded. The DNA was extracted from blood samples, and genotypes for 101 microsatellite markers were determined. Data of 466 individuals from 30 families were available for analysis. Interval mapping QTL analyses were carried out. The QTL significant at the genome wide level that affected body weight at two ages were identified on chromosomes 1, 2, 4, 7, and 8 and a QTL on Chromosome 13 influenced body weight at all three ages. Genetic effects were generally additive, and the broiler allele increased body weight in all cases. The effects for significant individual QTL accounted for between 0.2 and 1.0 phenotypic standard deviations and the sum of the additive effects accounted for approximately 0.75 of the line difference in body weight at 6 wk of age. The largest single additive effect was on chromosome 4, and the effect of substituting one copy of the gene was an increase in weight of 249 g. Interactions of the QTL with sex or family were unimportant. There was no evidence for imprinting or of two or more QTL at the same location for any of the traits.