Background: In commercial poultry production, where feed expenses account for about 70% of total costs, improving feed efficiency is crucial for profitability and sustainability. CSML exhibits a multi-Colored plumage and brown eggshells, closely resembling native desi birds, making it highly desirable for crossbreeding to improve indigenous poultry. 
 
Methods: A total of 100 CSML chicks were reared individually from 2 to 12 weeks of age to assess Feed Conversion Ratio (FCR), Residual Feed Intake (RFI), Residual body weight Gain (RG) and Residual Intake and Body Weight Gain (RIG). Based on these traits, birds were divided into high feed efficient (HFE) and low feed efficient (LFE) groups, with HFE representing the top 20% and LFE the bottom 20%. 
 
Result: HFE birds showed significantly better performance, gaining 7.87% body weight gain, consuming 9.96% less feed, achieved 17.25% better FCR and demonstrating improved RFI (179.86%), RG (220.03%) and RIG (182.50%) compared to LFE birds. Gene expression analysis via real-time qPCR revealed upregulation of SGLT1 (nutrient transporter) and GHRL (growth-related) genes and down regulation of CDx (gut development) genes in HFE birds, suggesting their role in feed efficiency. The study concludes that HFE CSML birds exhibit enhanced feed efficiency traits than LFE group, which can be used for production of high feed efficient hybrids. 
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Expression Profile of Feed Efficiency Related Genes in High and Low Feed-efficient Colored Synthetic Male Line (CSML) Broiler Chickens

<div style="text-align:justify">Background: Poultry production in rural India is mostly a non-intensive venture comprising native chicken with low production potential but higher disease resistance and adaptability. Present study is attempted for developing a suitable cross for rural poultry production as well as identifying the genetic groups that are nicking well through a partial diallel cross.&nbsp; 
 
Methods: A partial diallel cross using three genetic groups/ breeds of chicken viz. coloured synthetic male line (CSML), Local native chicken (Desi) and CARI-Red as the parent lines was designed. CSML was used as male and CR as female line only. The progenies were evaluated for crossbreeding parameters viz. combining abilities and heterosis for immune response and serum enzyme profile to identify the best combining parent lines. 
 
Result: Significantly higher (P&lt;0.05) cell-mediated (CMI) and humoral immune response (HIR) and immune organ (spleen, bursa of fabricius and thymus) weights were recorded in CR purebred followed by Desi purebred, while CSML purebred exhibited lowest immunity. Variances for SCA differed significantly (P&lt;0.001) for HIR and immune organ weights. Inconsistent but significantly higher (P&lt;0.01) serum enzymes (AST, ALT and ALP) and AST/ALT ratio were recorded in triple cross and D x CR. Variances for SCA differed significantly (P&lt;0.05) for serum enzymes. Results revealed that the CARI-Red and Desi were the improver parent lines for better immunocompetence and serum enzyme profile, respectively in the crosses.</div>

<div style="text-align:justify">Evaluation of Crossbreeding Parameters for Immunocompetence and Serum Enzyme Profile in a Partial Diallel Cross Involving Three Genetic Groups of Chicken</div>