Estensoro et al. (2016) evaluated the effects of adding Norel's GUSTOR BP70 to alleviate some negative effects of extreme plant-ingredient substitution of fish meal (FM) and fish oil (FO) in a gilthead sea bream diet.
In the first trial (T1), the best dose (0.4%) of BP70 was chosen after a short (9-weeks) feeding period. In the second longer trial (T2, 8 months), four diets were used: a control diet containing 25% FM (T2-D1) and three experimental diets containing 5% FM (T2-D2, T2-D3, T2-D4). FO was the only added oil in D1, while a mixture of vegetable oils replaced 58% and 84% of FO in T2-D2, and T2-D3 and T2-D4, respectively. The latter was complemented with 0.4% BP70. In a third trial (T3), two groups of fish were fed for 12 and 38 months with D1, D3 and D4 diets of T2.
The effects of dietary changes were studied using histochemical, immunohistochemically, molecular and electrophysiological techniques. Treatment T2-D3 modified significantly the transcriptomic profile, especially at the anterior intestine, up-regulating the expression of inflammatory markers, in coincidence with a higher presence of granulocytes and lymphocytes in the submucosa, and changing genes involved in antioxidant defenses, epithelial permeability and mucus production. Trans-epithelial electrical resistance was also decreased in T3-D3. Most of these modifications were returned to control values with the addition of BP70.
These results confirm the potential of GUSTOR BP70 to improve or reverse the detrimental effects of extreme fish diet formulas.
