Steelhead trout (Oncorhynchus mykiss) fed probiotic during the earliest developmental stages have enhanced growth rates and intestinal microbiome bacterial diversity

Sustainable aquaculture practices can help meet the increasing human demand for seafood, while easing pressures on natural fish populations. Studies aimed at production in have included supplementary dietary probiotics that often promote general health and enhanced growth rates by altering microbiome of host. Steelhead trout ( Oncorhynchus mykiss ) is anadromous, like salmon, it a subspecies rainbow capable rapid growth, making an attractive to industry. In this study, impact feeding Bacillus subtilis probiotic bacterial steelhead was examined temporally across several stages animal development, from eggs (day -19) through 184 days after hatching, relation physiological measures. Diets included: commercial feed only as control (A), continually-fed top-coated (B), then switch (C), or (D). Validation concentrations tissues performed using CFU/g qPCR, respectively. Fish measured samples intestinal analyses were collected multiple timepoints during development. fed diet D yielded higher weights than other three diets, with little biometric parameters. However, analysis indicated trend overall alpha diversity egg stage day 29 various diets having highest diversity. A maintained high beyond contrast decreased still being B C. The C harbored significantly relative abundance sp. their total microbiomes (feces + mucosa). Interestingly, mucosal-only variation between four groups fish. Feeding earlier hatchery phase, influence composition intestine (rather later has been established) appears be more effective practice enhancing enabling yields.