GAA in low metabolizable energy diet
- Post by: Admin
- January 20, 2024
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This study was aimed to explore the elevating energy utilization efficiency mechanism for the potentially ameliorative effect of guanidinoacetic acid (GAA) addition on growth performance of broilers fed a low metabolizable energy (LME) diet. A total of 576 day-old broilers were randomly allocated to one of the 6 treatments: a basal diet (normal ME, positive control, PC), or an LME diet (50 kcal/kg reduction in ME, negative control, NC) supplemented with 0.02, 0.04, 0.06 and 0.08 % GAA from 1 to 42 d of age, respectively. The GAA fortification in LME diet linearly or quadratically dropped (P < 0.05) the feed conversion ratio (FCR) from 22 to 42 and 1 to 42 d of age, abdominal fat rate on d 42, serum alanine aminotransferase (ALT) on d 21, and serum creatinine (CREAN) on d 21 and 42, elevated (P < 0.05) breast muscle rate and leg muscle rate on d 42, serum creatine kinase (CK) on d 21 and 42, as well as alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) on d 21. The dietary optimal GAA levels were 0.03-0.08% based on the best fitted quadratic models (P < 0.03) of the above parameters. Thus, the PC, LME and 0.04% GAA-LME groups were selected for further analysis. Serum essential amino acids (EAA) tryptophan, histidine and arginine, non-essential amino acids (NEEA) serine, glutamine and aspartic acid were significantly decreased (P < 0.05), compared to PC diet by LME or 0.04% GAA-LME diet. 0.04% GAA-LME group reversed (P < 0.05) the reduction of arginine, 3-methyhistidine and 1-methylhistidine by LME diet. Besides, 6 birds at 28 d of age from LME and 0.04% GAA-LME groups were selected for energy utilization observation in calorimetry chambers. The results demonstrated that 0.04% GAA-LME group significantly improved (P < 0.05) the ME intake (MEI) and net energy (NE) compared to the LME diet. Overall, these findings suggest that 0.04% GAA is the ideal dose of broilers fed the LME diet, which can significantly improve the growth performance and carcass characteristics by modulation of creatine metabolism through elevating serum CK activity and arginine concentration.