ASSOCIATION OF KRUPPEL-LIKE FACTOR-15 (KLF 15) GENE (EXON 2) POLYMORPHISM WITH BODY WEIGHT AND MORPHOMETRIC TRAITS IN IMPROVED NIGERIAN INDIGENOUS CHICKENS

Abstract

ABSTRACT Kruppel-like factors (KLFs) are transcriptional regulators that are members of the zinc-finger family, crucial for the expression, development, and differentiation of several mammalian cell types. This study was carried out to determine the relationship between KLF 15 gene polymorphism, body weight and morphometric traits in Nigerian indigenous chickens (NIC). A total of 250-day-old chick of Nigerian indigenous chickens were procured; and over the course of eight weeks, data on the morphometric traits of the birds were collected including the live body weight of the birds. At 8 weeks of age, a total of sixty (60) chickens were selected at random having 20 birds selected for each genotype while blood samples were collected from the chickens. Preliminary analysis including main and interaction effects of sex, chicken genotype, and KLF 15 genotype on body weight and morphometric traits were done but the effects of interaction were not significant while the evolutionary analysis was also conducted using Molecular Evolution and Genetic Analysis (MEGA X) software. The effects of genotype on body weight of NIC indicated that at weeks 4, 6, 7 and 8, normal feather chicken had significantly highest body weight (386.66±18.93g, 772.48±30.96, 1034.37±52.03g, 1158.13±51.99g) compared to naked neck (380.18±16.9g, 753.56±34.74g, 940.92±42.31g, 1140.06±45.63g) and frizzle feather (322.54±17.84g, 627.64±35.48g, 857.78±44.53g, 943.35±53.15g), respectively. The effect of genotype showed that Normal feather chicken had significantly (P<0.05) highest body length (19.15±0.40cm; 20.71±0.46cm) at week 7 and 8, respectively, compared to Frizzle feather and Naked neck. For thigh length, Frizzle feather chicken genotype was significantly higher (12.81±0.54cm) compared to Naked neck chickens. The Restriction Fragment Length Polymorphism (PCR-RFLP) patterns showed the genotypes of KLF 15 gene displayed the PCR products of size 1000bp DNA ladder with a single, specific and non-specific bands possessing two homozygous genotypes denoted as AA, BB, and one heterozygous genotype denoted as AB. Observed alleles and genotypic frequencies of KLF 15 gene locus in the chickens’ populations showed that AA was the only genotype to be the most common among the chickens. The highest genetic identity was observed between Naked neck and Frizzle feather chickens (0.995); and Normal feather and Frizzle feather chickens (0.995). The association of KLF 15 gene with body weight and morphometric traits of Nigerian indigenous chicken at various weeks showed that KLF 15 genotype AA, AB and BB with body weight and span length had significant (p<0.05) association at week 7, wing length at week 2 and week 8. It can be concluded that Normal feather chickens were superior to other genotypes in body weight and most body measurements and similar trend was observed for male chickens compared to female chickens while the evolutionary analysis showed that Normal feathers and Naked necks are closely related. Considering the superior body weight and measurements, Normal Feather chickens can be selectively bred to improve these traits across the population.