Effects of in-pond raceway system culture mode on muscle quality at different sites of tilapia

【Objective】The purpose of this study was to investigate the changes of various nutrient indicators of tilapia muscles under the in-pond raceway system(IPRS) culture mode,to clarify the effects of IPRS culture mode on muscle quality of tilapia, and to provide scientific basis for promoting IPRS culture modeand developing high quality tilapia culture. 【Method】IPRS-cultured tilapia were used as the experimental group and traditional pond aquaculture(TPA) tilapia were used as the control group. The nutrient indicators of the back, abdomen and tail muscles of tilapia, as well as the texture characteristics of the back muscles and the muscle fiber characteristics of tilapia under two culture modes were measured and analyzed. 【Result】The IPRS group had the highest crude protein content(19.62%) of abdomen muscle and the highest crude fat content(3.30%) of back muscle, and the difference in crude fat content in back muscle between IPRS and TPA groups was significant(P<0.05, the same below). Sixteen kinds of amino acids were detected at all sites in muscles of IPRS group and TPA group. The amino acid content of essential amino acids,delicious amino acids and total 16 amino acids were the highest in the back muscle of the IPRS group(7.41%, 7.22% and 18.41%) and lowest in the tail muscle of TPA(6.09%,5.89% and 15.20%). The contents of glutamic acid and aspartic acid among the four delicious amino acids in both IPRS and TPA groups ranked the first and second respectively,with the highest content being in the back muscle of the IPRS group(3.11% and 2.05%). The total amount of saturated fatty acids in the abdomen muscle was significantly lower in the IPRS group,and the total amounts of polyunsaturated fatty acids at different sites in muscles were increased extremely significantly(P<0.01). The total polyunsaturated fatty acids were the highest in the tail muscles of the IPRS group(31.53%) and the lowest in the back muscles of the TPA group(27.99%). Compared with the TPA group, muscle texture characteristics such as hardness, elasticity,chewiness and resilience of tilapia in the IPRS group increased by 24.89%, 18.19%,61.40% and 33.63% respectively. The muscle fibers of tilapia in IPRS group were smaller in diameter and denser than those in TPA group. 【Conclusion】The muscle quality and nutrition of tilapia cultured under inpond raceway system are more advantageous than those of tilapia in traditional pond aquaculture.