S. Senthil MuruganJORUGE NAGARJUNA DEEPAK2020-07-222020-07-222018http://krishikosh.egranth.ac.in/handle/1/5810149645The present study was intended to elucidate the effect of DL- methionine (110 per cent and 120 per cent of BIS recommendation 2007) supplementation on growth performance and gene expression pattern of myogenic family viz., myostatin (mstn), myogenic factor 5 (myf5), myocyte enhancer factor 2 family of transcription factor B (mef2b) in breast muscles of low hatch weight broiler chicks. One hundred and sixty numbers of day-old vencobb-400 broiler chicks which comprising of low and optimum hatch weight (120 and 40 respectively) were purchased from the local hatchery. The day-old chicks with optimum hatch weight (42.0 to 45.0 g) were grouped as G1 and chicks with low hatch weight (35.0-38.0g) were randomly allocated to groups G2, G3 and G4, with four replicates of ten chicks each by using completely randomised design (CRD). Experimental ration (R1) was prepared with BIS recommended DL-methionine (0.50, 0.50 and 0.45 per cent for broiler pre-starter, starter and finisher respectively). The experimental ration (R2) was prepared with 110 per cent of BIS (2007) recommended methionine (0.55, 0.55 and 0.50 per cent for broiler pre-starter, starter and finisher respectively). The experimental ration (R3) was prepared with 120 per cent of BIS (2007) recommended methionine (0.60, 0.60 and 0.54 per cent for broiler pre- starter, starter and finisher respectively). The groups G1 and G2 were fed with ration R1. The groups G3 and G4 were fed with rations R2 and R3 respectively, for a period of 42 days. The four birds form each group was sacrificed for study of carcass yield, breast yield along with gene expression studies. Dietary supplementation of DLMethionine had no significant effect on cumulative feed intake, body weight gain and FCR at the end of experiment but G3 showed better performance when compared with other groups. Over all five per cent mortality was observed. There was better carcass yield and breast yield in G3 when compared with other groups, without any significance difference among groups. The myogenic family mstn gene expression was downregulated in G2 group and upregulated in G3 and G4, but there was no significant difference between G1 and G2, whereas G3 and G4 showed significantly upregulation in gene expression study when compared with G1 group. myf5 gene was upregulated in G1 and G2 but downregulated in G3 and G4 but there was no significant difference among groups. The mef2b gene was upregulated in all groups but there was no significant difference between the gene expression among groups. The profit per kg live weight was highest for G3 than the other groups.ennullThesis