摘要
As a precursor to creatine, guanidinoacetic acid (GAA) is widely recognized to enhance growth performance and flesh quality of animals, but the underlying molecular mechanism remains unclear. This study evaluated the effects of dietary GAA supplementation on growth performance, textural properties, and flavor constituents in gibel carp CAS V ( Carassius gibelio , CAS V). A total of 300 healthy gibel carp (5.01 ± 0.13 g) at 42 d of age were assigned randomly to 12 tanks (3 replicates per group, 25 fish per replicate). Fish were fed with a basal diet supplemented with graded levels of GAA (0%, 0.03%, 0.06%, and 0.12%) for 10 weeks. Results demonstrated that GAA supplementation significantly enhanced the specific growth rate (SGR) and crude protein content in gibel carp ( P < 0.05). It also enhanced muscle physicochemical attributes by increasing water holding capacity and hardness, along with boosting glycogen content and free glutamate level ( P < 0.05). Mechanistically, GAA promoted myofiber development by upregulating protein and gene expression of myogenic regulatory factors (MRFs), leading to increase myofiber density and a higher frequency of myofibers with diameters between 20 and 40 μm ( P < 0.05). Furthermore, GAA facilitated collagen synthesis to improve muscle hardness by activating the transforming growth factor-beta 1 (TGF-β1)/mothers against decapentaplegic homolog (SMADs) signaling pathway, upregulating transcript levels of tgf-β1 , col1α1 , col1α2 , and smad3 ( P < 0.05). Additionally, GAA increased inosine monophosphate (IMP) content in muscle ( P = 0.015), which was associated with enhanced expression of AMPD1 protein and upregulation of the adsl , pkm , and ckm genes ( P < 0.05). In conclusion, dietary GAA supplementation enhanced flesh quality of gibel carp via improving growth performance, nutrient deposition, texture characteristics, and flavor components.
危险品化学品经营许可证（带存储）