Combined effects of exogenous enzymes and probiotic on Nile tilapia (Oreochromis niloticus) growth, intestinal morphology and microbiome

A study was carried out to investigate the combined effect of exogenous enzymes and probiotic supplementation on tilapia growth, intestinal morphology and microbiome composition. Tilapia (34.56 ± 0.05 g) were fed one of four diets (35% protein, 5% lipid); one of which was a control and the remaining three diets were supplemented with either enzymes (containing phytase, protease and xylanase), probiotic (containing Bacillus subtilis, Bacillus licheniformis and Bacillus pumilus) or enz-pro (the combination of the enzymes and probiotic). Tilapia fed diet supplemented with enz-pro performed better (P < 0.05) than tilapia fed the control and probiotic supplemented diets in terms of final body weight (FBW), specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER). The dietary treatments did not affect somatic indices. The serum lysozyme activity was significantly higher (P < 0.05) in tilapia fed the probiotic supplemented diet than of those fed the remaining experimental diets. The intestinal perimeter ratio was higher (P < 0.05) in tilapia fed enz-pro supplemented diet when compared to those fed with the control and probiotic supplemented diets. Goblet cells abundance, microvilli diameter and total enterocyte absorptive surface was higher (P < 0.05) in tilapia fed diet supplemented with enz-pro than those fed the control diet. High-throughput sequencing revealed that majority of reads derived from the tilapia digesta belonged to members of Fusobacteria (predominantly Cetobacterium) distantly followed by Proteobacteria and Firmicutes. The alpha and beta diversities did not differ among dietary treatments indicating that the overall microbial community was not modified to a large extent by dietary treatment. In conclusion, supplementation of the diet with a combination of enzymes and probiotic is capable of improving tilapia growth and intestinal morphology without deleterious effect on the intestinal microbial composition

Projecting Climate Dependent Coastal Flood Risk With a Hybrid Statistical Dynamical Model

ABSTRACT: Numerical models for tides, storm surge, and wave runup have demonstrated ability to accurately define spatially varying flood surfaces. However these models are typically too computationally expensive to dynamically simulate the full parameter space of future oceanographic, atmospheric, and hydrologic conditions that will constructively compound in the nearshore to cause both extreme event and nuisance flooding during the 21st century. A surrogate modeling framework of waves, winds, and tides is developed in this study to efficiently predict spatially varying nearshore and estuarine water levels contingent on any combination of offshore forcing conditions. The surrogate models are coupled with a time-dependent stochastic climate emulator that provides efficient downscaling for hypothetical iterations of offshore conditions. Together, the hybrid statistical-dynamical framework can assess present day and future coastal flood risk, including the chronological characteristics of individual flood and wave-induced dune overtopping events and their changes into the future. The framework is demonstrated at Naval Base Coronado in San Diego, CA, utilizing the regional Coastal Storm Modeling System (CoSMoS; composed of Delft3D and XBeach) as the dynamic simulator and Gaussian process regression as the surrogate modeling tool. Validation of the framework uses both in-situ tide gauge observations within San Diego Bay, and a nearshore cross-shore array deployment of pressure sensors in the open beach surf zone. The framework reveals the relative influence of large-scale climate variability on future coastal flood resilience metrics relevant to the management of an open coast artificial berm, as well as the stochastic nature of future total water levels.This work was funded by the Strategic Environmental Research Development Program (DOD/SERDP RC-2644). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. F. J. Mendez, A. Rueda, and L. Cagigal acknowledge the partial funding from the Spanish Ministry of Science and Innovation, project Beach4cast PID2019-107053RB-I00. The authors thank the Scripps Center for Coastal Studies for their efforts to deploy, recover, and process surf zone pressure sensor data used as validation in this study. The authors thank Melisa Menendez for sharing GOW2 hindcast data for Southern California. The authors thank the sea-level rise projection authors for developing and making the sea-level rise projections available, multiple funding agencies for supporting the development of the projections, and the NASA Sea-Level Change Team for developing and hosting the IPCC AR6 Sea-Level Projection Tool

Supplementation of formulated diets for tilapia (Oreochromis niloticus) with selected exogenous enzymes: Overall performance and effects on intestinal histology and microbiota

keywords: Phytase keywords: Phytase keywords: Phytase keywords: Phytase keywords: Phytase keywords: PhytaseAbstract This study was conducted to evaluate the effects of exogenous enzymes on Nile tilapia (Oreochromis niloticus) growth and general health status. Tilapia (38.7 g) were fed one of four plant-based diets (408 g kg−1protein, 78 g kg−1 lipid); one of which was a control and the remaining three were supplemented with exogenous enzymes (phytase, protease and carbohydrase at 300 mg kg−1, 200 mg kg−1, and 300 mg kg−1, respectively). Tilapia fed the phytase supplemented diet displayed higher final body weight, FBW (94.9 g fish−1) and specific growth rate, SGR (2.48% day−1) compared to tilapia fed the control diet (82.6 g fish−1 FBW and 2.11% day−1 SGR) (P &lt; 0.05). In terms of feed conversion ratio, FCR and protein efficiency ratio, PER, tilapia fed diet supplemented with phytase (1.36 FCR and 1.08 PER) performed better (P &lt; 0.05) than tilapia fed the control diet (1.68 FCR and 0.80 PER). However, the dietary treatments had no significant effect on tilapia somatic indices (P ˃ 0.05). The level of circulatory red blood cells was higher (P &lt; 0.05) in tilapia fed the carbohydrase supplemented diet (1.98 × 106 μL−1) compare to those fed the control diet. Dietary treatments did not affect the mid-intestinal perimeter ratio, goblet cell abundance and intraepithelial leucocytes abundance. However, the microvilli density of the mid-intestine was higher (P &lt; 0.05) in tilapia fed the phytase (15.6) and carbohydrase (16.0) supplemented diets compared to those fed the control (10.4) and protease (11.5) supplemented diets. The intestinal bacterial community profile of tilapia fed the carbohydrase supplemented diet was significantly altered in contrast to those fed the control diet (P &lt; 0.05). The supplementation of diets with phytase has the potential to enhance tilapia growth without detrimental impacts on intestinal health