Modulation of intestinal health and hepatic vacuolation in gilthead sea bream (Sparus aurata) juveniles by a mixture of dietary esterified butyrins, emulsifiers from plants and yeast extracts at low and high fish meal inclusion

This study examined the modulatory effect of two commercial feed additives, Lumance (R) (0.2% and 0.5%) and Novigest (R) (0.4%), on the growth and microscopic structure of the intestine and liver of juvenile gilthead sea bream (Sparus aurata), when added to high (HFM-0) and low fish meal (LFM-0) diets. Lumance (R) was added only in the HFM-0 diet (HFM-0.2 and HFM-0.5), while a mixture of the two additives was used in the LFM-0 diet (LFM-0.6: 0.2% Lumance (R) + 0.4% Novigest (R) and LFM.0.9: 0.5% Lumance (R) + 0.4% Novigest (R)). Fish fed the HFM diets exhibited the highest overall growth, and significant differences were recorded in the specific growth rate (SGR), daily growth index (DGI), feed conversion ratio (FCR) and thermal growth coefficient (TGC), between the HFM and LFM dietary treatment groups. Supplementation of the additives had no effect on the growth performance in either of these groups. The analysis of the intestinal histomorphometric measurements showed signs of intestinal inflammation in the fish fed the LFM-0 diet. The addition of the two additives exhibited some modulatory effects, particularly increased intestinal villi length and lamina propria width in the mid-intestine. An increased number of intraepithelial cells and mucus production was also observed, as well as a decrease in hepatic vacuolation in the LFM-0.6 and LFM-0.9 groups, but not at a statistically significant level