Flesh Shear Force, Cooking Loss, Muscle Antioxidant Status and Relative Expression of Signaling Molecules (Nrf2, Keap1, TOR, and CK2) and Their Target Genes in Young Grass Carp (Ctenopharyngodon idella) Muscle Fed with Graded Levels of Choline

Abstract

Six groups of grass carp (average weight 266.9 ± 0.6 g) were fed diets containing 197, 385, 770, 1082, 1436 and 1795 mg choline/kg, for 8 weeks. Fish growth, and muscle nutrient (protein, fat and amino acid) content of young grass carp were significantly improved by appropriate dietary choline. Furthermore, muscle hydroxyproline concentration, lactate content and shear force were improved by optimum dietary choline supplementation. However, the muscle pH value, cooking loss and cathepsins activities showed an opposite trend. Additionally, optimum dietary choline supplementation attenuated muscle oxidative damage in grass carp. The muscle antioxidant enzyme (catalase and glutathione reductase did not change) activities and glutathione content were enhanced by optimum dietary choline supplementation. Muscle cooking loss was negatively correlated with antioxidant enzyme activities and glutathione content. At the gene level, these antioxidant enzymes, as well as the targets of rapamycin, casein kinase 2 and NF-E2-related factor 2 transcripts in fish muscle were always up-regulated by suitable choline. However, suitable choline significantly decreased Kelch-like ECH-associated protein 1 a (Keap1a) and Kelch-like ECH-associated protein 1 b (Keap1b) mRNA levels in muscle. In conclusion, suitable dietary choline enhanced fish flesh quality, and the decreased cooking loss was due to the elevated antioxidant status that may be regulated by Nrf2 signaling.

Dietary choline regulates antibacterial activity, inflammatory response and barrier function in the gills of grass carp (Ctenopharyngodon idella)

“…1) and 1555.0 (Fig. 2) mg choline/kg diet, respectively, which were higher than that based on growth [4]. The results indicated for the first time that choline requirements of fish for immunity and antioxidant were higher than that for growth.…”

“…Hence, the health of gills is very important for fish growth [2]. Choline is an essential vitamin for fish [3] and has been demonstrated that appropriate dietary choline could improve the growth of young grass carp (Ctenopharyngodon idella) in our previous study [4]. These studies indicating that choline may have some effects on gill health status of fish.…”

“…In our previous study, optimal choline markedly improved the growth performance of grass carp [4]. Fish growth is partly related to the health of fish gill.…”

“…Our previous study indicated that choline deficiency decreased growth performance of young grass carp [4]. To our knowledge, the fish growth performance is often related to gill health, which mainly correlates with the immunity and structure integrity in the gill of fish [2].…”

Effects of dietary vitamin C on growth, flesh quality and antioxidant capacity of juvenile golden pompanoTrachinotus ovatus

“…The WHC of muscle is another important flesh quality parameter and also associated with lipid oxidation. Zhao et al () found that the increase in MDA content in muscle of grass carp ( Ctenopharyngodon idella ) resulted in a decrease in WHC, which was measured by determining the CL (Skipnes, Østby, & Hendrickx, ) and DL (Wan et al, ) of muscle in fish. In the current study, it was observed that the CL and DL in muscle of T. ovatus fed with diet D3 were lower than the other groups, suggesting that 59.10 mg/kg dietary VC level could enhance the WHC of fish fillets to improve the flesh quality.…”