Diets supplemented with phytobiotics Calopogonium mucunoides, Ocimum gratissimum, and Tridax procumbens improve growth, immunity, and Oreochromis niloticus resistance to Streptococcus agalactiae.

This research examined how three phytobiotics impact the growth, utilization of feed, immune response, and resistance of Nile tilapia (Oreochromis niloticus) to disease. A total of 180 fish, with an average initial weight of 31.2 g (number = 15 per 150-L tank), were randomly divided into four groups, with each group replicated three times. Fish were fed isoenergetic (15.7 kJ g⁻¹ gross energy) or isonitrogenous (262 g/kg⁻¹ crude protein) control diets supplemented with 1% Calopogonium mucunoides, Ocimum gratissimum, or Tridax procumbens leaf meals, and the feeding trial lasted 10 weeks. The growth performance, feed utilization, and innate immunity of the fish were measured. Ten fish from each replicate were intraperitoneally injected with Streptococcus agalactiae, and mortality was recorded for 18 days. The O. niloticus fed phytobiotic-enriched diets exhibited significantly greater weight gain (68.6 ± 3.7; 70.3 ± 1.6; 71.6 ± 2.9) and specific growth rates (1.70 ± 0.05; 1.71 ± 0.01; 1.73 ± 0.06) than did those in the control group (55.3 ± 1.1; 1.50 ± 0.05). Additionally, phytobiotic supplementation in Nile tilapia diets positively impacted feed conversion efficiency, protein efficiency ratio, feed conversion ratio, hematocrit, hemoglobin, red blood cells, lymphocyte count, serum protein profile, glucose level, kidney-liver function, and bactericidal and lysozyme activities. Following the challenge with S. agalactiae, the survival rates were significantly greater (p < 0.05) in the fish fed a diet supplemented with O. gratissimum (70%), T. procumbens (63.3%), or C. mucunoides (53.3%) than in those in the control group (26.3%). The abovementioned phytobiotics incorporated into Nile tilapia feed can boost production and enhance growth performance, feed efficiency, immunity, and resistance to disease. [ABSTRACT FROM AUTHOR]