Benefits of a commercial solid-state fermentation (SSF) product on growth performance, feed efficiency and gut morphology of juvenile Nile tilapia (Oreochromis niloticus) fed different UK lupin meal cultivars

A nutritional investigation was conducted to determine whether growth performance, feed efficiency and midgut morphology of Nile tilapia is affected by United Kingdom cultivars of Yellow Lupin (Control, Y) (YLC) or Blue Lupin (Control, B) (BLC) inclusions compared to the addition of a commercial solid-state fermentation product (SSF) in separate dietary treatments for both lupin cultivars (YLS and BLS). After 49 days of feeding, tilapia receiving SSF supplemented diets (YLS & BLS) exhibited significantly greater weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and condition factor (K) compared to YLC or BLC without solid state fermentation. SSF inclusion exhibited significantly improving of enterocyte height within both the first and second half of the experiment (P < .05). The surface area of the midgut was not affected by lupin type or SSF (P > .05); although a potential response over time was apparent in the YLS group. Enterocyte microvilli were significantly wider in fish fed YLC diets (P < .05), whilst they were significantly longer in the BLC control compared to the YLC control (P < .05). Microvilli lengths of fish fed YLS were comparable to those receiving BLC diets and close to being significantly longer than those fed YLC alone (P = .06). Overall, BLC appeared to perform superiorly to YLC; whilst SSF inclusion promoted some desirable production parameters, seemingly most effectively in the YLC diet.