Effect of dietary protein and carbohydrate levels on weight gain and gonad production in the sea urchin Lytechinus variegatus

Abstract

Adult Lytechinus variegatus were fed eight formulated diets with different protein (ranging from 12 to 36%) and carbohydrate (ranging from 21 to 39 %) levels. Each sea urchin (n = 8 per treatment) was fed a daily sub-satiation ration of 1.5% of average body weight for 9 weeks. Akaike information criterion analysis was used to compare six different hypothesized dietary composition models across eight growth measurements. Dietary protein level and protein: energy ratio were the best models for prediction of total weight gain. Diets with the highest (> 68.6 mg P kcal−-1) protein: energy ratios produced the most wet weight gain after 9 weeks. Dietary carbohydrate level was a poor predictor for most growth parameters examined in this study. However, the model containing a protein × carbohydrate interaction effect was the best model for protein efficiency ratio (PER). PER decreased with increasing dietary protein level, more so at higher carbohydrate levels. Food conversion ratio (FCR) was best modeled by total dietary energy levels: Higher energy diets produced lower FCRs. Dietary protein level was the best model of gonad wet weight gain. These data suggest that variations in dietary nutrients and energy differentially affect organismal growth and growth of body components.

Growth rates are related to production efficiencies in juveniles of the sea urchinLytechinus variegatus

“…The direct effects of these specific nutrients are not addressed in this study and are presented in the aforementioned citations. Sea urchins were fed daily a sub-satiation ration based on body weight (2.5–5% total average body weight), found previously to support weight gain (Heflin et al ., 2012a). Sub-satiation feeding allows a direct measurement of feed intake (Heflin et al ., 2012a).…”

Balancing macronutrient intake in cultured Lytechinus variegatus

“…Previous studies indicate that lipid requirements among sea urchins are low (Gibbs et al, 2009) and excess intake of dietary lipid restricts growth in L. variegatus (Gibbs et al, 2009). In contrast, increasing levels of dietary protein are associated with increased growth and production (Hammer et al, 2012;Heflin et al, 2012), suggesting that protein is most likely required at higher levels than lipid for…”

“…Sea urchins have been shown to tolerate high levels of purified starch and protein in their diets (Heflin et al, 2012). The fish meal hydrosylate contained ca.…”

“…Urchins had been held on a maintenance diet previously shown to maintain survival and health (Hammer et al, 2012;Heflin et al, 2012). Urchins were assigned haphazardly to 1 of 4 treatments (n =5 urchins per treatment) and were then placed individually into rectangular plastic mesh cages (14.4 x24.8 x 15.2 cm, L x W x H).…”

Effect of Diet Quality on Nutrient Allocation to the Test and Aristotle's Lantern in the Sea UrchinLytechinus variegatus(LAMARCK, 1816)

“…In sea urchins, protein and carbohydrate are the two primary energy sources used for maintenance and growth (Marsh and Watts, 2007). Protein, carbohydrate, and their value as anabolic precursors and energy sources affected total body weight gain in L. variegatus (Heflin, 2010). Dietary changes in their profiles could potentially affect organ growth of the test, lantern and spines.…”