Expression of major histocompatibility complex class II gene in commercial strains of broiler chickens administered varying levels of aqueous ginger extract

Abstract

Due to regulation on the usage of synthetic antibiotics as a result of the development of resistance by microorganisms, the expression of Major Histocompatibility Complex (MHC) class II gene in three commercial strains of broiler chickens administered varying levels of ginger extract was investigated. Ninety each of Arbor acres Plus, Cobb 500 and Ross 308 were used in the experiment. The birds were randomly divided into three treatment groups, on breed basis, of 30 birds, designated as T1, T2, and T3. Each treatment per breed were further divided into 3 replicates of 10 chicks. The control was administered a leveled table spoonful of Oxytetracycline® in 2L of water as recommended by the manufacturer while 4% and 6% of aqueous ginger extract was given to treatment 2, and 3 birds, respectively via drinking water. A single phase diet (22.34% CP; 2948.05 ME kcal/kg) was fed to the birds for 8 weeks. Liver samples were collected at the end of the experiment, fixed in RNA Later, and used for the expression study. Results showed significant (P<0.05) effect of treatment on the expression of MHC complex class II gene of the birds. Arbor acres Plus, Cobb 500 and Ross 308 birds administered ginger extract expressed more of the gene compared to the control. For the breed effect, expression of MHC class II gene was better in Ross 308 strain (1.07 fold change) followed by Arbor acres plus (0.76 fold change) while Cobb 500 had the least (0.62 fold change). For the effect of varying ginger extract levels on the expression of MHC class II gene, it was observed to have been upregulated most in birds administered 4% ginger extract (1.26 FC), 6% ginger extract (1.19 FC), while the control (0% ) had the least value (0.00 FC). In conclusion, aqueous ginger extract could be used up to 6% in the drinking water of the three broiler chickens strains as it led to upregulation of the MHC class II gene expression which could help in conferring immunity to the birds against exogenous microbial infection