Effect of Guanidinoacetic Acid on Production Performance, Serum Biochemistry, Meat Quality and Rumen Fermentation in Hu Sheep.

Simple Summary: Recently, the escalating prices of feedstuff resources have posed significant challenges to animal husbandry, necessitating the creation of innovative approaches to mitigate its effects. GAA (also known as N-amidinoglycine) serves as the sole precursor for creatine synthesis. GAA could enhance growth performance and regulate fat deposition to improve meat quality. Current studies on GAA mainly center on pigs and chickens, with limited reports on its effects on sheep. In our study, we used weaned Hu sheep as subjects. We aimed to explore the impact of dietary GAA supplementation on production performance, serum biochemistry, meat quality and rumen fermentation. This study provides a theoretical foundation for utilizing GAA in sheep meat production. Our findings indicate that GAA enhances growth performance, rumen fermentation and fat accumulation. In addition, GAA might enhance the quality of sheep meat, which presents a promising prospect for meat sheep breeding. Guanidinoacetic acid (GAA) can effectively improve the metabolism of energy and proteins by stimulating creatine biosynthesis. We present a study exploring the impact of GAA on production performance, serum biochemistry, meat quality and rumen fermentation in Hu sheep. A total of 144 weaned male Hu sheep (body weight 16.91 ± 3.1 kg) were randomly assigned to four groups with three replicates of twelve sheep in each group. The diets were supplemented with 0 (CON), 500 (GAA−1), 750 (GAA−2) and 1000 mg/kg (GAA−3) of GAA (weight of feed), respectively. After a comprehensive 90-day experimental period, we discovered that the supplementation of GAA had a remarkable impact on various muscle parameters. Specifically, it significantly enhanced the average daily growth (ADG) of the animals and improved the shear force and fiber diameter of the muscle, while also reducing the drip loss and muscle fiber density. Furthermore, the addition of GAA to the feed notably elevated the serum concentrations of high-density lipoprotein cholesterol (HDL−C), total protein (TP) and globulin (GLB), as well as the enzyme activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH−Px). Concurrently, there was a decrease in the levels of triglycerides (TG) and malondialdehyde (MDA) in the serum. In addition, GAA decreased the pH and the acetate-to-propionate ratio and increased the total volatile fatty acids (TVFA) and ammoniacal nitrogen (NH3−N) levels of rumen fluid. Additionally, GAA upregulated acetyl-CoA carboxylase (ACC) gene expression in the Hu sheep's muscles. In conclusion, our findings suggest that GAA supplementation not only enhances muscle quality but also positively affects serum biochemistry and ruminal metabolism, making it a potential candidate for improving the overall health and performance of Hu sheep. [ABSTRACT FROM AUTHOR]