Vol. 9, Special Issue 2, Part H (2025)

The present study was conducted on 160 layer birds to assess the effect of betaine hydrochloride supplementation on blood biochemistry, gut morphology, gut microflora and expression of toll like receptor genes related to immunity. The birds were randomly assigned to five treatment groups (B0.0, B0.5, B1.0, B1.5, and B2.0), with each group consisting of four replicates of eight birds. Group B0.0 served as the control, while the treatment groups received 0.5, 1.0, 1.5, and 2.0 g/kg of betaine hydrochloride, respectively. Results showed that betaine supplementation significantly improved nutrient metabolizability, hematological parameters, including hemoglobin, total erythrocyte count and total leukocyte count, with the highest values observed in the B2.0 group. The serum lipid profiles were positively affected, with decreased cholesterol, triglyceride and LDL levels, and increased HDL levels, with the maximum effects (p<0.05) noted in B2.0 group compared to control B0.0. Additionally, the mean values of serum albumin, globulin, and total protein were significantly higher (p<0.05) in all betaine-supplemented groups, with the highest values observed in the B2.0 group. In gut health indices, the villi height: crypt depth ratio was noted highest (p<0.05) in B2.0 group when compared with the control group. In the microbial count also, harmful pathogens like E.coli and Salmonella decreased while Lactobacilli increased in betaine treated groups with the highest effects noted in B2.0 indicating a healthy gut environment. The relative genomic expression of toll like receptors 2 and 7 was up-regulated while TLR 4 was down-regulated, with the most profound changes occurring in B2.0 group indicating a robust immune function. These findings suggest that dietary betaine hydrochloride supplementation can have beneficial effects on layer bird health, particularly at the highest dose of 2 g/kg.