Effects of Cu2+-exchanged montmorillonite on intestinal microflora, digestibility and digestive enzyme activities of Nile tilapia

A total of 360 Nile tilapia at an average initial body weight of 3.9 g were randomly allocated to four treatments, each of which had three replicates of 30 fish per tank and used to investigate the effects of Cu2+-exchanged montmorillonite (Cu-MMT) on intestinal microflora, digestibility and digestive enzyme activities. The dietary treatments were: (i) basal diet, (ii) basal diet + 1.5 g kg−1 MMT; (iii) basal diet + 30 mg kg−1 copper as CuSO4 (equivalent to the copper in the Cu-MMT treatment group), or (iv) basal diet + 1.5 g kg−1 Cu-MMT. The results showed that supplementation with Cu-MMT significantly improved growth performance as compared with the control and fish fed with Cu-MMT had higher growth performance than those fed with MMT or CuSO4. Supplementation with Cu-MMT reduced (P   0.05) effect on intestinal microflora, digestibility, and digestive enzyme activities the results showed that Cu-MMT exhibited antibacterial activity in vivo resulting in a positive effect on digestive enzyme activities, and then promoted the digestion and absorption of dietary nutrition.