Effect of Naked Neck Gene on Immune Competence, Serum Biochemical and Carcass Traits in Chickens under a Tropical Climate

Abstract

A comprehensive study was undertaken to evaluate the effect of naked neck (Na) gene on immune competence, serum biochemical parameters and carcass quality traits in three genotypes (NaNa, Nana and nana) of the naked neck chicken under a tropical climate (Southern India). Sixty day-old chicks (20 from each genotype) were selected randomly and reared under similar environmental conditions up to eight weeks of age. The cell mediated immune (CMI) response to phytohaemoagglutinin-P (PHA-P) was significantly higher (p≤0.01) in NaNa and Nana genotypes compared to nana birds. The humoral response as measured by antibody titre to sheep red blood cells (SRBC) was also significantly higher in NaNa. The total cholesterol, LDL and VLDL cholesterol levels were significantly (p≤0.01) lower whereas HDL cholesterol level was significantly higher in NaNa and Nana compared to nana genotype. The presence of Na allele significantly increased the live weight and dressing yield, and decreased the feather cover and abdominal fat. The naked neck genotypes (NaNa/Nana) performed better than the normal (nana) siblings for almost all the traits studied.

Phenotypic Characterization of Indian Naked Neck Chicken Under Tropical Climatic Conditions

“…The h 2 estimates for 4th week body weight were higher for dam component than that of sire, while for 6th week it is vice-versa indicating the substantial additive genetic variance that can be transmitted to the next generation. The results were in accordance with the reports of Reddy et al (2008) and Rajkumar et al (2010a) in naked neck broilers. Further, these are found to be at higher end than indicated by Adeyinka et al (2006) in Nigerian naked neck broilers.…”

Effects of strain and sex on the behaviour of free-range slow-growing chickens raised in a hot environment

“…The NN chickens possess better post-weaning heat tolerance than OV and PK due to the reduced plumage cover which is effective in minimizing heat stress where birds have to dissipate excess heat (Cahaner et al 1993;Deeb & Cahaner 2001;Raju et al 2004;Fathi et al 2013). The NN carry an autosomal incompletely dominant gene (Na) which results in a 30% reduction in overall plumage cover for heterozygotes and 40% for homozygotes, which are associated with increased thermal tolerance (Raju et al 2004;Rajkumar et al 2010;Fathi et al 2013). In the current study, one behaviour that perhaps demonstrates the marginal advantage of the NN, over other strains, is the more time spent walking by chickens in this group, perhaps suggesting greater adaptability.…”

“…The reduced feather cover in the NN strain may be of advantage in thermoregulation at high ambient temperature (Eberhart & Washburn 1993). The strain carries a gene which results in reduced overall plumage cover (Rajkumar et al 2010;Fathi et al 2013). The OV is a predominantly dark coloured fairly heavy strain that attains sexual maturity at average weights of 2.2 kg for males and 1.5 kg for females about 140 d of age (Nthimo et al 2004).…”

Physiological Responses of Slow-Growing Chickens under Diurnally Cycling Temperature in a Hot Environment

“…They are known to be heat tolerant and generally adapted to harsh environmental conditions. They carry a gene which results in reduced overall feather cover (Rajkumar et al, 2010;. This reduced feather cover is thought to be advantageous for thermoregulation and it is thought that the thermoregulatory ability of this strain at high temperature is slightly better than that of normally feathered birds (Rajkumar et al, 2010;.…”

“…They carry a gene which results in reduced overall feather cover (Rajkumar et al, 2010;. This reduced feather cover is thought to be advantageous for thermoregulation and it is thought that the thermoregulatory ability of this strain at high temperature is slightly better than that of normally feathered birds (Rajkumar et al, 2010;. The OV is a predominantly dark coloured fairly heavy strain that attains sexual maturity at average weights of 2.16 kg for males and 1.54 kg for females at about 140 d of age (Nthimo et al, 2004).…”