Prebiotic agavin in juvenile totoaba, Totoaba macdonaldi diets, to relieve soybean meal‐induced enteritis: Growth performance, gut histology and microbiota

The prebiotic effect of the agave plant polysaccharides (agavin) was evaluated to improve enteritis caused by soybean meal (SBM) in juveniles of Totoaba macdonaldi (60.8 ± 2.3 g). Four isoproteic and isolipidic diets were formulated: an FM‐based formulation as reference (RD), a blend of FM and PBM (FM‐PBM; 1:2 as previously shown better performance than FM), the blend combined with 24% SBM (SBM‐B) and, lastly, the latter combination with 2% agavin (SBM‐B + A). After 44 days, the SBM‐B + A treatment resulted in a definite enteritis improvement, besides a significantly higher final growth (207.1 ± 3.8 vs. 195 ± 3.4) compared to the rest of the treatments. According to the microbiota intestine structure, it can be revealed that agavin resulted in enrichment of the Sinorhizobium genera, characterized by nitrogen fixation. However, at a species level, Clostridium botyricum was the more prominent in PBM‐based feeds, known as beneficial for the suppression of inflammatory response. In contrast, Enterococcus cecorum was identified in the gut of fish fed SBM‐based feeds, intensified in agavin‐supplemented feeds. Higher expression of hsp70 and aqp8 was registered in FM‐PBM. It is concluded that agavin provides a clear benefit when added to diets. The implications of FM substitution are discussed.