Growth performance, body chemical compsitions and digestive enzymes in grey mullet ,Mugil cephalus Linnaeus 1758, fed with different levels of Saccharomyces cerevisiae yeast

Probiotics, as a live microbial dietary supplement, play an important role in the growth and activity of the host digestive enzymes by balancing the gut microbial population.The present study  was conducted with 4 treatments and 3 replications including diets containing 1×10⁶, 3×10⁶ and 5 ×10⁶ (cell/ g feed) and control (basal diet without yeast) to evaluate the effect of different levels of dietary supplementation of  Saccharomyces cerevisiae on growth performance, body biochemical composition and digestive enzymes activities of grey mullet, Mugil cephalus.The fish (5.56±0.65 g)  were  randomly  allocated  into  12  fiberglass tanks at a density of  20 individuals  per  tank  with  three  replicates  for  each treatment  and fed  with the experimental diets for 60 days. The results indicated that the  diet  at  5×10⁶  yeast cells/ g( significantly improved  weight gain (240.36±13.57%), final weight (919.28±1.55), protein efficiency (10.01± 0.56%) and survival (94.40±13.57%) compared  to  the  control  and treatment 2 (p<0.05). Also, the highest activity of amylase (199.50±17.70 U/mg protein) and protease (362.50±13.52 U/mg protein) were observed in 5×10⁶  yeast cells/ g  diet (P<0.05). This study shows that the use of S. cerevisiae  3×10⁶ and 5 ×10⁶ yeast cell/ g feed can have positive effects on growth performance, feed utilization, body chemical composition and digestive enzymes activities of M. cephalus.