OPTIMIZING FULL PLANT PROTEIN FEED THROUGH NUTRITIONAL AND UN-NUTRITIONAL METHODS ON THE COMPOSITIONS AND TEXTURE PROPERTIES OF LARGEMOUTH BASS MICROPTERUS SALMOIDES MUSCLE

The effects of optimizing full plant protein feed through nutritional and non-nutritional methods on the compositions and texture properties of largemouth bass muscle were investigated. Nine extruded experimental feeds were formulated, including a fish meal control feed (FFH), full plant protein feed (PFH), softened feed (PFS), DMPT supplemented feed (PFD), taurine supplemented feed (PFT), cholesterol & fish oil feed (PFC), soybean oil feed (PSH), cholesterol & soybean oil feed (PSC), and comprehensive feed (PFA). Twenty-seven tanks of largemouth bass with an initial body weight of (78.1±0.06) g were fed for 50d in an indoor recirculating aquaculture system (RAS). The results indicated that crude fat content in the dorsal muscle of fish from the PFH group was significantly higher than that of the FFH group, while muscle hardness, adhesiveness, springiness, gumminess, and chewiness of fish from the PFH group were significantly lower than those in the FFH group. The muscle crude fat content of fish in the nutrient-optimized groups (PFD, PFT, PFC, PFA, and PSH) were significantly lower than that in the PFH group. Muscle adhesiveness, gumminess, and chewiness were significantly increased in the PFD group; muscle hardness and gumminess were significantly increased in the PFT group; muscle hardness, gumminess, and chewiness were significantly increased in the PFC and PFA groups; and muscle hardness, springiness, gumminess, and chewiness were significantly increased in the PSH group. Regarding the non-nutritional way, compared to the PFH group, muscle hardness, adhesiveness, gumminess, and chewiness were significantly increased in the PFS group. Compared to the PSH group, muscle springiness in the PSC group was significantly reduced. Correlation analysis showed that muscle hardness, adhesiveness, gumminess, and chewiness had a significantly negative correlation with muscle fat content. Muscle hardness showed a significantly positive correlation with adhesiveness, gumminess, and chewiness. Muscle springiness showed a significantly positive correlation with gumminess and chewiness, and muscle gumminess showed a significantly positive correlation with chewiness. These results indicate that optimizing full plant protein feed nutritionally with dietary supplements of DMPT, taurine, cholesterol, or by substituting soybean oil for fish oil, can partially improve the muscle quality of largemouth bass, which may have been impaired by the intake of full plant protein feed previously. The results of the present experiment could potentially benefit the wide application of full plant protein feed and promote the sustainable development of largemouth bass farming.