RNA/DNA ratio is an early responding, accurate performance parameter in growth experiments of noble crayfishAstacus astacus(L.)

Abstract

Recent intensification efforts of astacid culture considerably depend on the appropriate assessment of the animal's physiological condition both for research and application. We conducted a 4 weeks feeding experiment to assess temporal resolution and accuracy of different response parameters (RNA/DNA ratio, RNA per wet weight, carapace length, wet weight, specific growth rate). Juvenile noble crayfish were exposed to five feeding regimes that differed in feeding frequency and food availability. Continuous growth was detected in all feeding regimes with individual increase up to 90% (wet weight) and 17% (carapace length), respectively. Morphometric parameters allowed separation of three weight-groups or two lengthgroups. During the experimental period RNA/ DNA ratios showed both decrease (À17%) and increase (+35%), with superior accuracy than morphometric parameters, separating four groups. Based on RNA/DNA ratios, different feeding regimes were detected earlier, with two groups separated already after 3 weeks. RNA/DNA ratio was clearly superior to RNA per unit wet weight, as the latter failed to detect any differences between groups. In conclusion, RNA/DNA ratio is a valuable tool in nutritional studies with freshwater crayfish if overall growth is the key variable of interest.

Growth performance, nucleic acids, leptin and adiponectin and their receptor gene expression were significantly affected by feeding different lipid supplementation in GIFT tilapia juveniles

“…The RNA content and RNA/DNA ratio were the physiological indicators of protein synthesis ability in vivo, which could reflect the nutrition and growth status of the body. However, RNA/DNA ratio could be used to more accurately evaluate the short‐term and long‐term growth status of fish, which had practical value (Grimm et al., 2015; Gupta et al., 2015; Labh et al., 2014). There was significant positive correlation between muscle growth and body growth ( R 2 = 0.9459) in the experiment.…”

Relationship of RNA/DNA ratio to somatic growth of Nile tilapia juveniles (Oreochromis niloticus) under joint effects of temperature and salinity

“…; Buckley ; Mathers, Houlihan, McCarthy & Burren ; Buckley, Caldarone & Ong ). In addition, because nutrition level is closely associated with growth, some researchers have used RNA/DNA ratio to assess nutritional status in fish (Richard, Bergeron, Boulhic, Galois & Le Ruyet ; Canino ; Clemmensen ; Gwak, Tsusaki & Tanaka ; Tanaka, Satoh, Yamada, Takebe, Nikaido & Shiozawa ), mollusks (Fathallah, Medhioub, Medhioub & Boussetta ) and crustaceans (Juan et al ., 2013; Grimm, Lehmann, Clemmesen & Brendelberger ).…”

Evaluating the Nutritional Condition of an Indian Climbing Perch, Anabas Testudineus Fingerlings by the RNA/DNA, Ca/P Ratio and Protein Bio-Synthesis in Liver and Muscle

“…Similar observations have been reported by Austreng and Refstie in rainbow trout, Viola and Zohar in market size hybrids of Tilapia (Oreochromis sp. ), Machiels and Henken in Clarias gariepinus, Patra in Clarias batrachus and in Anabas testudineus [5,15,32,33]. Results also indicate that the weight gain with 40% protein diet (ED05) in not significantly higher than the fish fed with the diet having 35% crude protein level (ED04).…”

“…Survival of young fish can be controlled both by predation and starvation, and by the interaction of these two factors, because starving fish larva/fry are more vulnerable to predation [7]. "The nutritional condition of larval/fry fish, which is the key factor in this context, can be characterized histologically [8] by measuring proteolytic enzymes [9] or the RNA/DNA ratio [10][11][12][13][14][15]. "…”