Dietary four different woody forages differentially affect the growth, feed utilization, apparent digestibility, intestinal morphology and microbiota composition in Nile tilapia (Oreochromis niloticus)

Woody forage as potential aquatic feed ingredient has a positive effect on tilapia survival and feed utilization. To study the effect of woody forages on the growth, feed utilization, apparent digestibility, intestinal morphology and microbiota composition of Nile tilapia (Oreochromis niloticus), the diets of Moringa oleifera Lam (MOL), Folium mori (FM), Broussonetia papyrifera (BP) and Neolamarckia cadamba (NC) formulated with 70 % of reference (Ref) diet and 30 % corresponding woody leaves were fed to Nile tilapia (12.0 ± 1.0 g) for 55 days, respectively. Results showed that the tilapia dietary MOL had a significant highest final body weight (FBW), weight gain (WG) and lowest feed conversion rate (FCR), while the tilapia dietary NC had a lowest FBW, WG and highest FCR. Although no significant difference in enzyme activities was found among each groups, the enzyme activities (gastric protease and foregut lipase) of tilapia dietary MOL and FM were higher compared with BP and NC. Moreover, the tilapia dietary BP got a significantly highest apparent digestibility (dry matter, crude protein and crude fat) compared with others. Furthermore, the thickness of the muscular layer in foregut and hindgut were significantly decreased in tilapia dietary MOL and increased in tilapia dietary NC. In addition, a much more number of bacterial operational taxonomic units (OTUs) and specialized gut bacterial community were found in tilapia dietary MOL, FM, BP and NC compared with Ref. In conclusion, woody forages (MOL, FM and BP) can be used as potential aquatic feed ingredients without negative effects on growth and intestinal health in Nile tilapia. Adding 30 % MOL to the diet could bring a positive influence on growth, feed utilization and microbiota composition of Nile tilapia, while adding 30 % NC brought negative influence.