Growth Performance, Antioxidants, Intestinal Microbial Composition and Histological Effect of Grass Carp (Ctenopharyngodon idella) through diets Enriched to Pomegranate Peel (Punica granatum) Extracts

Graphical Abstract Highlight Research • PPE supported the growth indices like final weight, weight gain, SGR, and FCR. • PPE affected the total aerobic bacteria or total lactic acid bacteria (LAB) count, but the enteric gram-negative bacteria count was significantly reduced in the experimental groups. • Add PPE caused a reduced total fungi count in all treated fish. • The histological examination showed enlargement of the villi, depth of the villi, and an increase in goblet cells for the treatments supplemented with PPE. Abstract Pomegranate is considered one of the medicinal herbs rich in antioxidants that can be used in aquaculture to support immunity and health. The objective of this investigation was to ascertain the impact of pomegranate peel (Punica granatum) extract (PPE) on growth performance, the intestinal bacteria count, the total number of fungi and the histological analysis of the grass carp. 105 fingerlings (11.04±0.22g) were distributed among 21 aquariums (60-L) in a completely randomised design (triplicated) and fed diets containing 0, 0.5, and 1% PPE for 70 days at a feeding rate of 3% body weight. A spectrophotometry assessment indicated for PPE that the total phenol content was 151.09 and 175.95 GAE/100 g, and the flavonoid content was 36.04 and 42.89 RE/100 g, respectively. The results of the present work revealed that growth indicators (final weight, weight gain, specific growth rate (SGR), and feed conversion ratio (FCR)) increased (P