Biology subjects

Bell, M. E.

Publications and source records attributed to Bell, M. E..

7 recordsLinked to original sources

bioRxiv2025

True Digestibility and Growth Response of Coated Essential Amino Acid Supplementation in Plant-Based Feeds for Rainbow Trout (Oncorhynchus mykiss)

In order to assess the efficacy of using essential amino acids to support the inclusion of high plant based proteins in diets for rainbow trout, a 56-day growth and feed utilisation study was conducted with juvenile (60g) rainbow trout (Oncorhynchus mykiss) under controlled conditions. Fish were fed diets where a predominately white fishmeal based control diet was compared to diets where full fat soyabean meal (FFS) as well as maize gluten meal (MGM) were incorporated respectively at significant levels (up to 75% of the fishmeal). Ten essential amino acids (EAAs) supplemented these diets in both standard and coated forms to evaluate their potential to rebalance the dietary EAA profiles more precisely. All diets were adjusted to be isonitrogenous and isolipidic. In addition to the growth trial, a low purified protein diet was fed to the fish separately (at a mean weight of 200g) to collect faeces for determining endogenous protein loss as well as the individual experimental diets described. As such it was possible to calculate the true digestibility for essential amino acids. The results indicated that corrective amino acid fortification of high plant diets, especially MGM could significantly (P<0.05) improve trout performance and raise their nutritional value. This was confirmed by final body weight, specific growth rate, feed conversion ratio and protein utilisation values. The true digestibility of the EAAs were similar and the values of each digestible EAA but coated EAAs were slightly superior in their digestibility coefficients. Coated EAAs improved digestibility coefficients by 2-5% and FCR by 8% compared to crystalline forms and also improved their utilisation leading to better trout performance with respect to growth, feed conversion efficiency and Nitrogen (crude protein) retention (P<0.05). The findings are discussed in the context of sustainable feeds and the circular bioeconomy for fish farming.

physiology↗

bioRxiv2024

Coated crystalline essential amino acid supplementation supports high soybean meal inclusion in diets for Nile tilapia (Oreochromis niloticus) with improved protein retention and nutrient assimilation

The aquaculture industry has previously relied on high-quality fishmeal (FM) to produce diets of excellent standards. However, plant-based proteins such as soybean are more cost-effective for low-value fish species, for example, tilapia and carp, and fishmeal use has been significantly diminished. Previous studies have mainly addressed standard soybean meal (SBM) sources in aquafeeds. A 55-day feeding trial was conducted to investigate the replacement of fish meal with soybean meal concentrate in Nile tilapia (Oreochromis niloticus) using a semi-purified diet approach against a Low Temperature (LT) fishmeal as a primary reference protein. Four diets with different levels of soybean meal were evaluated and compared to a control diet of 100 % fish meal. Three diets containing 20, 40, and 80 % soybean protein concentrate (SBPC) were examined. The fourth diet consisted of 80 % SBPC and two essential amino acids: lysine and methionine (80SBPCAA) in a coated form. The average daily growth values highlight similar daily growth rates when tilapia was fed 100FM and 40SBPC. No significant differences were observed in the final mean weight for all soybean-fed tilapia, but they were marginally lower than the 100FM control diet group. The 80SBPC diet showed the poorest feed conversion ratio (FCR) at 1.31 and protein efficiency ratio (PER) at 2.19. However, the 80SBPCAA diet showed a significantly improved result for per cent weight gain compared to the 80SBPC-fed tilapia. Also, protein efficiency ratio was significantly higher at 2.47 and had a better Apparent Net Protein Utilization (ANPU) value of 28.51 % compared to un-supplemented 80SBPC-fed tilapia (25.48 %). These results confirmed that high-quality fishmeal can be substituted by up to 40 % SBPC alone and without any detrimental effects on growth or carcass composition. Further studies on plant proteins and supplementary amino acids as a suitable alternative for replacing high-quality fishmeal may promote a more sustainable aquaculture industry.

developmental biology↗

bioRxiv2024

Colour preference in juvenile European lobster (Homarus gammarus)

Lobsters are high-value marine-fished species, and re-stocking efforts are essential for replenishing depleted wild populations and ensuring the longevity of these valuable marine species. The need for stock enhancement and hatcheries for aquaculture is vital to reduce the strain on wild populations. Therefore, environmental colours should be acknowledged when rearing lobsters in terms of behaviour, growth, movement, and survival. However, the behavioural effects the surrounding colour poses are virtually unknown. To better understand this behaviour, the movement of juvenile European lobsters (Homarus gammarus) was analysed through videos in two sub-trials. Lobsters were acclimated to custom-made alternating colour chambers, allowing for colour preferences based on individual movement. Sub-trial one alternated between black, red, blue, green, white, and yellow. The study identified that there was a significant preference for black (1 hour and 51 minutes) and red (1 hour and 33 minutes), indicating a potential underlying benefit for juvenile H. gammarus development. Despite this, little is known about the overall association of colour and lobster perception. A better understanding of environmental colour preference may guide the construction of aquaculture units to suit colour preference and enhance acclimation into newly released environments. This experiment aims to determine the preferred colours of stage four juvenile H. gammarus in a controlled laboratory setting and inspire further research to explore this unfamiliar field.

animal behavior and cognition↗

bioRxiv2023

Nutritional value of extracted soybean, full fat soya and maize gluten meal proteins in comparison to a fishmeal-based reference diet for fingerling tilapia (Oreochromis mossambicus)

A two-month investigation evaluated potential selected plant protein sources compared to fish meal protein in scientifically formulated diets for fingerling tilapia (Oreochromis mossambicus). Six nutritionally balanced diets: one reference (control) diet (fish-meal-based diet), three selected plant proteins (solvent extracted soybean, full fat soybean, and maize gluten) were substituted in the LT (Low Temperature dried) fish-meal-based control diet protein at 50% respectively, and the remaining diets were replaced with 75% inclusion of solvent extracted soybean and maize gluten meals. Results showed that SESB50, FFSB50 and MG50 fed tilapia did not appreciably differ in their growthperformance (final mean weights of 12.07, 10.75 and 9.18% respectively) with a final mean weight of 14.95g being significantly superior for the fish meal control (CO) group. Substitution of fish meal diet with solvent-extracted soybean and maize gluten at levels of 75% gave the poorest growth performance and Feed Efficiency (FE) (7.01g final weight, 51% FE). However, the MG50 diet also showed some inferior feed utilisation performance. However, tilapia fed on a full fat soybean diet (FFSB50) did not vary significantly from the control (CON) diet in terms of Apparent Net Protein Utilisation (ANPU) at 34.20 and 37.53% respectively. Whilst this preliminary study concluded that limitations on the use of the selected plant proteins in diets for tilapia are apparent, several approaches that could result in the future improvement of the nutritional value of soybean and maize gluten products for use in fish diets are also stated. HighlightsA scientifically formulated reference diet using a Low Temperature dried (LT) fish meal produced superior growth performance for fingerling tilapia compared to selected oilseed (soybean) and grain (maize gluten) derived protein concentrates. Soybean and full fat soybean meals were effective in contributing to 50% inclusion in experimental diets, but 75% of soybean and maize gluten meal was not able to support similar growth of tilapia over eight weeks. Feed utilisation parameters such as Protein Efficiency Ratio (PER), Apparent Net Protein Utilisation (ANPU), Net Energy Utilisation (NEU) and Feed Efficiency (FE) gave supporting evidence and conclusions for optimal threshold inclusions of the test plant ingredients for tilapia.

developmental biology↗

bioRxiv2023

Influence of pseudo-green water on growth, colouration, and survival in European lobster (Homarus gammarus) larvae

With the depletion of European lobster (Homarus gammarus) wild stocks from historic overexploitation, the attention has turned towards restocking, stock enhancement programs and farming potential. The early life larval stages of the European lobster present a major barrier to hatchery production efforts due to low survival rates. Green water techniques are rapidly growing due to their ability to improve nutrition quality. This study explores the potential benefits of using pseudo-green water. This is determined by adding microalgae to the rearing environment of larvae by analysing the effects on growth and survival. The commonly used algal species: Tetraselmis suecica (TS), Dunaliella salina (DS), and Nannochloropsis sp. (N) were added as monoculture or mixture treatments to a controlled European lobster larvae-rearing environment over thirteen days. The trial consisted of seven permutations of algal treatments (TS, DS, N, TS+DS, TS+N, DS+N, and TS+DS+N) and one control group, with clear water conditions using length measurements, survival rates and colouration to determine treatment impacts at the end of the trial. Results indicate that mixtures of algal species outperformed monocultures and clear water regarding growth performance. Nannochloropsis sp. is of significant benefit to growth performance. Algal mixes containing Nannochloropsis sp. resulted in significantly better growth than D. salina monoculture treatment. There were no significant differences in survival rates between treatment groups.

developmental biology↗

bioRxiv2022

Silent recognition of flagellins from human gut commensal bacteria by Toll-like receptor 5

Flagellin, the protein unit of the bacterial flagellum, stimulates the innate immune receptor Toll-like receptor (TLR)5 following pattern recognition, or evades TLR5 through lack of recognition. This binary response fails to explain the weak agonism of flagellins from commensal bacteria, raising the question of how TLR5 response is tuned. Here, we describe a novel class of flagellin-TLR5 interaction, termed silent recognition. Silent flagellins are weak agonists despite high affinity binding to TLR5. This dynamic response is tuned by TLR5-flagellin interaction distal to the site of pattern recognition. Silent flagellins are produced primarily by the abundant gut bacteria Lachnospiraceae and are enriched in non-Western populations. These findings provide a mechanism for the innate immune system to tolerate commensal-derived flagellins. One-Sentence SummaryTLR5 sensitively recognizes, but responds weakly to, flagellins from gut commensal bacteria.

microbiology↗

bioRxiv2017

Resilience mechanisms of small intestinal lactobacilli to the toxicity of soybean oil fatty acids

Over the past century, soybean oil (SBO) consumption in the United States increased dramatically. The main SBO fatty acid, linoleic acid (18:2), inhibits in vitro the growth of lactobacilli, beneficial members of the small intestinal microbiota. Human-associated lactobacilli have declined in prevalence in Western microbiomes, but how dietary changes may have impacted their ecology is unclear. Here, we compared the in vitro and in vivo effects of 18:2 on Lactobacillus reuteri and L. johnsonii. Directed evolution in vitro in both species led to strong 18:2 resistance with mutations in genes for lipid biosynthesis, acid stress, and the cell membrane or wall. Small-intestinal Lactobacillus populations in mice were unaffected by chronic and acute 18:2 exposure, yet harbored both 18:2- sensitive and resistant strains. This work shows that extant small intestinal lactobacilli are protected from toxic dietary components via the gut environment as well as their own capacity to evolve resistance.

microbiology↗