Effects of dietary supplementation with cinnamon powder and lysine on blood chemistry, liver histology, growth performance, and fillet quality of striped catfish Pangasianodon hypophthalmus

Dietary cinnamon and lysine supplementation could increase the utilization of nonprotein nutrients and spare the use of protein as an energy source, inhibit lipogenesis, and subsequently improve meat quality. This study evaluated the effect of dietary supplementation with cinnamon, high levels of lysine and their combination on the blood chemistry, liver histology, fillet quality, and growth performance of the striped catfish Pangasianodon hypophthalmus in the grow-out stage. Four iso-nitrogenous experimental diets with a crude protein content of 25.56-25.90% and lipid content of 5.50-5.83% were tested: the diet with no supplementation of either cinnamon or lysine that served as the control (C), diets supplemented with either cinnamon at 10 g kg(-1) (CP) or high lysine at 16 g kg(-1) (HL), and a diet with a combination of both cinnamon and high lysine (CP + HL). The tested diets were administered to the fish (272.83 +/- 3.55 g), which were maintained in 12 net cages (four treatments and three replicates) with a size of 1 x 1 x 2 m(3) at a density of 20 fish per cage. The fish were fed the tested diets to apparent satiation three times a day, and after 60 days, the fish were weighed to evaluate growth, and then whole fish, muscle, liver, and blood plasma samples were also collected to examine the chemical composition, muscle characteristic, and the blood biochemistry. The present study shows significant differences between CP, HL, and dan CP + HL diets compared to the C diets based on plasma protein (28.53 g dL(-1) vs 36.82, 37.28, 34.64 g dL(-1), respectively), albumin (3.28 g dL(-1) vs 3.65, 3.71, 4.15 g dL(-1), respectively), whole body lipid (14.56% vs 12.52, 12.56, 12.71%, respectively), muscle lipid (6.62% vs 4.16, 4.20, 3.78%, respectively), muscle protein (15.90% vs 17.63, 17.02, 17.53%, respectively), mono unsaturated fatty acid (39.50% vs 39.07, 38.48, 34.97%, respectively), n3 poly unsaturated fatty acid (2.05% vs 2.53, 2.65, 2,98%, respectively), n6 poly unsaturated fatty acid (10.64% vs 10.06, 10.36, 11.08%, respectively), muscle brightness (46.69 vs 52.14, 49.08, 52.92, respectively), muscle hardness (574 gf vs 768, 755, 664 gf, respectively), specific growth rate (1.32% day(-1) vs 1.47, 1.58, 1.42% day(-1), respectively), and feed conversion ratio (2.89 vs 2.50, 2.25, 2.60, respectively). Hepato-somatic index (1.95% vs 1.65, 1.81, 1.71%, respectively) and liver lipid (3.35% vs 2.89, 2.10, 2.80%, respectively) decreased as the histological structure of liver improved. Overall, the present study demonstrated that CP and HL diets resulted in beneficial effects on striped catfish blood chemistry, fillet quality, and growth with the HL diet showing the best results. The CP + HL diet demonstrated synergistic effects only on lipid loss but not on growth parameters.