¹Department of Animal Science, Science and Research Branch, Islamic Azad University, Tehran, IRAN
²Department of Biotechnology, University of Imam Khomeini, Qazvin, IRAN
³Animal Science Research Institute of Iran, Karaj, IRAN DOI : 10.9775/kvfd.2016.17289 The objective of the current work was to evaluate the effect of drinking water with various levels of total dissolved solids (TDS) and betaine supplementation on the performance and gene expression of betaine-homocysteine S-methyltransferase (BHMT) in broiler chickens. In a completely randomized design with a 3×2 factorial arrangement, chicks were assigned to six treatments with four replicates and 15 chicks per each. The treatments were included of three levels of total dissolved solids (400, 2.000 and 3.500 ppm) and two levels of betaine supplementation (0 and 0.2% of diet). Weight gain decreased and feed conversion ratio and water intake increased as TDS of water increased. Betaine supplementation had no effect on weight gain and water intake during the grower period, but had a significant effect on gain and feed conversion ratio in the finisher period. Mortality rate and excreta moisture content increased as TDS of water increased. Excreta moisture content decreased with betaine supplementation. Gene expression of BHMT decreased significantly with increases in TDS level and betaine supplementation increased its expression (28 folds) as compared with the non-additive group. It was concluded that consumption of drinking water with higher than 2.000 ppm TDS adversely and betaine supplementation positively affect the performance of broiler chickens. The lowest feed conversion ratio was seen in chicks fed 400 and 2.000 ppm TDS with betaine supplementation. Keywords : Betaine, Blood parameters, Broiler chick, Gene expression, Performance, Total dissolved solids