Dietary protein requirement of juvenile kelp grouper ( Epinephelus moara )

Abstract

Dietary protein requirement of juvenile kelp grouper Epinephelus moara was investigated through a feeding trial. Experimental diets with graded crude protein (CP) levels (33.01%, 38.54%, 45.21%, 50.71%, 56.10% and 63.09% of dry matter respectively) were formulated. Six triplicate groups of fish (20 individuals per replicate with initial mean weight 6.00 g) were fed with each diet for 8 weeks. Best growth performance of fish was detected in 56.10% CP diet. The specific growth rate (SGR) significantly elevated with increasing dietary CP level to 50.71%, but there was no significant difference thereafter (p < .05). The feed conversion ratio (FCR) decreased significantly with dietary CP levels from 33.01% to 56.10% (p < .05). Glucose (GLU) and total protein (TP) concentrations in plasma had an increasing trend with dietary protein increasing. In the 33.01% CP group, plasma triglyceride (TG) content was significantly higher (1.67 mmol/L) than that in other dietary treatments (0.65–1.14 mmol/L). The lowest alanine transaminase (ALT) activity was observed in the 56.10% CP group (163.16 U/L). Crude lipid content in the muscle and liver was significantly elevated with increasing dietary protein levels (p < .05). The glycogen content in the liver decreased significantly as CP levels increased (p < .05). The fish fed diet with higher CP level (56.10% and 63.09%) had significantly higher energy retention (ER) and lipid retention (LR) than other treatments. Based on the broken‐line regression analysis of SGR and FCR, the optimal dietary protein requirement for juvenile kelp grouper is 54.61%–56.22%.

Dietary protein requirement for large‐size Songpu mirror carp ( Cyprinus carpio Songpu)

“…Related studies reported that superior growth and excellent health status were often accompanied by the lower values of HIS and the higher values of CF (Kim et al., 2016; Wang et al., 2016; Ye, Wu, et al, 2017; Ye, Han, et al, 2017). Our study also found that the highest WGR and the lowest HSI were obtained in the 260 g/kg crude protein group, which is consistent with that reported in juvenile kelp grouper ( Epinephelus moa ra) (Su et al., 2019).…”

Advances in practical feed formulation and adoption for hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂) aquaculture

“…Efficiency of nutrient retention decreases as fish grow 22,24 as an increased proportion of energy is used for maintenance in larger fish. 14 This results in poorer feed conversion for larger fish, as exemplified by FCR values less than 1 for grouper less than 100 g body weight 25,26 as long as feeds are nutrient-balanced. 27 The few data available for larger grouper indicate higher FCR values of 1.4-2.0 for E. fuscoguttatus and E. coioides of approximately 100-600 g body weight [28][29][30] and 1.2-1.6 for TGGG of 182-971 g body weight 31 which is consistent with decreasing nutrient efficiency as reported for groupers and other finfish species as they grow.…”

Metabolomic and transcriptomic profiling reveals the effect of dietary protein and lipid levels on growth performance in loach (Paramisgurnus dabryanus)

“…Research on suitable feed formulations is essential for the aquaculture industry. Inappropriate protein and lipid levels lead to poor fish growth (13,(37)(38)(39)(40). Therefore, by feeding diets with different dietary protein and lipid levels, exploring the mechanisms behind the differences in growth of P. dabryanus is critical to setting optimal nutrient requirements and achieving optimal aquaculture growth rates.…”