Dietary protein/lipid level and protein source effects on growth, tissue composition and lipid metabolism of blackspot seabream (Pagellus bogaraveo)

Abstract

A study was carried out to determine the effects of fish meal (FM) replacement by plant protein (PP) on growth, body composition and lipid metabolism of blackspot seabream fed different protein/lipid levels. Four experimental diets were formulated to contain two protein (P) and lipid (L) levels (60P/6L or 50P/10L), varying in their protein source (100% FM or 50% FM: 50% PP). Dietary inclusion of PP did not affect growth of fish fed 60P/6L, although fish fed 50P/10L exhibited lower final body weight and daily growth index. Fish fed 60P/6L presented the highest protein and the lowest lipid content. FM replacement by PP has decreased muscle n‐3 whereas the n‐6 fatty acids increased. Glucose‐6‐phosphate dehydrogenase and fatty acid synthetase (FAS) were depressed in fish fed 50P/10L. FAS was significantly increased with 60P/6L PP which was positively correlated with lipid retention data. Those results suggest the conversion of other nutrient than lipid (protein and/or carbohydrates) into corporal fat. Hepatic lipoprotein lipase activity was lowest in fish fed PP diets. Plasma glucose peaked 1–2 h postfeeding, in all groups and was generally higher with 60P/6L FM. This work shown that besides dietary P/L level, protein source has a strong effect on species lipogenesis and lipid retention. Hence, the 50P/10L FM diet was the most cost‐effective for blackspot seabream juveniles.

Protein-sparing effect of dietary lipid in practical diets for blunt snout bream (Megalobrama amblycephala) fingerlings: effects on digestive and metabolic responses

“…Actually, fish fed diet 270/100 obtained the lowest WG, the highest body lipid and hepatosomatic index (HSI) among all the treatments in our previous study (Li et al 2010). The highest liver lipid also was observed in Atlantic salmon (Salmo salar L.) (Einen and Roem 1997), African catfish Clarias gariepinus (Burchell, 1822) (Ali and Jauncey 2005), red porgy (Pagrus pagrus) (Schuchardt et al 2008) and blackspot seabream (Pagellus bogaraveo) (Figueiredo-Silva et al 2010) fed diets containing the lowest P/E ratio. In addition, liver lipid content in this study showed little difference among all the treatments in terms of dietary lipid levels.…”

Effects of dietary lipid levels on growth, feed utilization, body composition, fatty acid profiles and antioxidant parameters of juvenile chu’s croaker Nibea coibor

“…It is widely accepted that fatty acid composition of tissues is influenced by the fatty acid composition of dietary lipids, and marine fish species have a specific requirements for the HUFAs 20:4n-6, 20:5n-3 and 22:6n-3 (Díaz- López et al 2010;Figueiredo-Silva et al 2010). In our study, the proportion of MUFA was found to decrease in tissues, while HUFA was selectively accumulated in muscle compared to the experimental diets (HUFA in liver was detected to stay roughly the same).…”

Regulation of metabolism by dietary carbohydrates in two lines of rainbow trout divergently selected for muscle fat content

“…-1 malonyl-CoA) were assessed following the method described in Figueiredo-Silva et al (Figueiredo-Silva et al, 2010) adapted to trout tissues. PK enzyme activity was measured as described by Kirchner et al (Kirchner et al, 2003).…”