Feeding common sole (Solea solea) juveniles with increasing dietary lipid levels affects growth, feed utilization and gut health

Abstract

Knowledge about the nutritional requirements of common sole (Solea solea) is limited and no information regarding the optimal dietary lipid level is available yet. Thus, this study was undertaken to assess the growth response and feed utilization of common sole juveniles fed diets with increasing lipid levels. Four isonitrogenous (59% protein) pelletized diets with different dietary lipid levels (8, 12, 16 and 20%; L8, L12, L16 and L20, respectively) were fed to triplicate fish groups of 80 individuals to apparent satiation over 150 days. A one-way ANOVA, Tukey's post hoc test and linear regression were used to analyse the data (P ≤ 0.05). At the end of the trial, final body weight was significantly higher in fish fed L8 (40.7 ± 1.7 g), followed by those fed L12 (35.1 ± 1.2 g), L16 (27.9 ± 2.5 g) and L20 (22.1 ± 0.3 g). The specific growth rate was higher in fish fed L8 and L12, compared to the other treatments, and it was lowest in L20. Voluntary feed intake decreased with an increase in the dietary lipid level. The feed conversion rate, the protein efficiency ratio and the gross protein efficiency were lower in fish fed L20, while no significant differences were observed among L8, L12 and L16. Gross lipid efficiency was significantly higher in fish fed low lipid diets.Histological observations showed that 19 of 36 observed subjects had lipid droplets in the cytoplasm of enterocytes at the apex of the mucosal folds and, in some cases, also along the entire fold (intestinal steatosis). The number of fish with intestinal steatosis in groups L20 and L16 was significantly higher than the number in group L8.Ultrastructure showed large electrondense lipid droplets within the cytoplasm of enterocytes and warping of the cytoplasmic membrane (steatosis); in some cases, lipid droplets were also present within the Golgi apparatus.In conclusion, the results of this trial suggest that the diet for Solea solea juveniles should include no more than 12% lipids. Higher lipid inclusions not only led to a substantial decline in performance but also affected gut health. This should be taken into consideration in formulating specific practical diets for common sole.

Effects of dietary lipid levels on growth, fatty acid composition, antioxidant status and lipid metabolism in juvenileOnychostoma macrolepis

“…In this study of juvenile O. macrolepis , there occurred better survival and growth performance at L9 and L12. Comparison of the different treatments indicated that where the dietary lipid levels increased above 11.95% the growth of fish, such as juvenile tench ( Tinca tinca L.; Sáez‐Royuela, Casado, Celada, Carral, & González‐Rodríguez, ), Common sole ( Solea solea ; Bonvini et al, ), Senegalese sole ( Solea senegalensis ; Borges et al, ) and turbot ( Psetta maxima ; Regost et al, ), tended to be depressed. It was showed that there were significantly higher lipid contents in the whole body and hepatopancreas of juvenile O. macrolepis fed on the experimental diets with a dietary lipid content of 11.95% or higher.…”

Effects of dietary carbohydrate/lipid ratios on growth, body composition, and nutrient utilization of hybrid catfish (Pseudoplatystoma reticulatum x Leiarius marmoratus)

“…Other researchers found that Chinese longsnout catfish achieves the best growth with 1.63:1 CHO:L ratio (Pei et al, 2004), close to the results of the present study. Diets higher to 12% lipid inclusion for common sole (Selea solea) juveniles not only led to a substantial decline in performance but also affected gut health (Bonvini et al, 2015). In omnivorous warm-water fish such as channel catfish (Ictalurus punctatus), common carp (Cyprinus carpio) and tilapia (Oreochromis niloticus), dietary carbohydrates, mainly starch, constitute the main non-protein energy source (Wilson, 1994;Vásquez-Torres and AriasCastellanos, 2012).…”

Effects of Different Dietary Carbohydrate/Lipid Ratios on Growth, Feed Utilization and Body Composition of Early Giant Grouper Epinephelus Lanceolatus Juveniles

“…As one of the macronutrients in aquatic feed, lipid has many advantages for fish growth, but in comparison to CHO, it is more expensive and less available, especially so for fish oil. Excess lipids in diets usually increase lipid deposition in fish carcass [8,9], lead to a substantial decline in performance, affect gut health [10] and increase susceptibility to autoxidation and tissue lipid peroxidation, which may also adversely affect the immune response and disease resistance of fish [11].…”