Effect of Nanoencapsulated Alginate-Synbiotic on Gut Microflora Balance, Immunity, and Growth Performance of Growing Rabbits.

A synbiotic comprising yeast (SCY) and leaf extract (MOLE) has been encapsulated using nanotechnology. This duo is used as a dietary supplement for growing rabbits. Physicochemical analyses, in vitro antimicrobial activity, and gastrointestinal system evaluation were used to evaluate the quality of the nanofabricated synbiotic. The in vivo study was conducted using 40-day-old male growing rabbits (n = 16 rabbits/group) to evaluate the effect of the nanofabricated synbiotic on the health and growth performance of examined rabbits. Rabbits were equally allocated into four groups; (a) NCS, which received a basal diet supplemented with a noncapsulated 11 × 10 CFU SCY + 0.15 g MOLE/kg diet, (b) LCS: those receiving a nanoencapsulated 5.5 × 10 CFU SCY + 0.075 g MOLE/kg diet, (c) HCS: those receiving an 11 × 10 CFU SCY + 0.15 g MOLE/kg diet, and (d) CON: those receiving a basal diet without treatment (control). The treatments continued from day 40 to day 89 of age. During the experimental period, growth performance variables, including body weight (BW), feed consumption, BW gain, and feed conversion ratio were recorded weekly. Blood samples were collected on day 40 of age and immediately before the start of the treatments to confirm the homogeneity of rabbits among groups. On day 89 of age, blood samples, intestinal, and cecal samples were individually collected from eight randomly selected rabbits. The size and polydispersity index of the nanofabricated synbiotic were 51.38 nm and 0.177, respectively. Results revealed that the encapsulation process significantly improved yeast survival through the gastrointestinal tract, specifically in stomach acidic conditions, and significantly increased in vitro inhibitory activities against tested pathogens. Furthermore, treatments had no negative effects on hematobiochemical variables but significantly improved levels of blood plasma, total protein, and insulin-like growth factor-l. Compared to the CON, NCS, and LCS treatments, the HCS treatment increased the amount of intestinal and cecal yeast cells ( < 0.05) and bacteria ( < 0.05) and decreased number of ( < 0.05) and ( = 0.08) bacteria. Likewise, both LCS and HCS significantly improved the small intestine and cecum lengths compared to CON and NCS. The HCS treatment also significantly improved BW gain and feed conversion compared to CON treatment, whereas the NCS and LCS treatments showed intermediate values. Conclusively, the nanoencapsulation process improved the biological efficiency of the innovative synbiotic used in this study. A high dose of encapsulated synbiotic balanced the gut microflora, resulting in the growth of rabbits during the fattening period.