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Long-term toxicity to aquatic invertebrates

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Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
other: Publication
Adequacy of study:
weight of evidence
Study period:
2021
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
This study aimed to assess the effects of S. cerevisiae YFI-SC2 on the growth, immunity,
and intestinal health of crayfish.
GLP compliance:
not specified
Specific details on test material used for the study:
Spent brewer's yeast
Test organisms (species):
other aquatic crustacea: Procambarus clarkia
Details on test organisms:
Crayfish
Key result
Duration:
28 d
Dose descriptor:
other: Not applicable
Effect conc.:
0 other: Not applicable
Conc. based on:
other: Not applicable
Remarks:
Not applicable
Basis for effect:
other: Not applicable
Remarks on result:
other: The results demonstrated that the addition of S. cerevisiae to the feed could improve the growth performance, the immune response, the intestinal morphology, the structure of intestinal microbiota, and the resistance to pathogens of crayfish
Validity criteria fulfilled:
not applicable
Conclusions:
Diseases of crayfish (Procambarus clarkia) are closely related to intestinal health. Therefore, it is important for crayfish aquaculture to keep intestinal health in an optimum condition. As a beneficial fungus, Saccharomyces cerevisiae can effectively compete to inhibit the reproduction of pathogenic bacteria, regulate the intestinal microecosystem, and promote animal growth and disease resistance. This study aimed to assess the effects of S. cerevisiae YFI-SC2 on the growth, immunity, and intestinal health of crayfish. The results demonstrated that the addition of S. cerevisiae to the feed could improve the growth performance, the immune response, the intestinal morphology, the structure of intestinal microbiota, and the resistance to pathogens of crayfish. Therefore, S. cerevisiae can be used as a potential probiotic in crayfish farming.
Executive summary:

The present study aimed to evaluate the effect of the dietary supplementation of Saccharomyces cerevisiae YFI-SC2 on the growth performance, intestinal morphology, immune parameters, intestinal microbiota, and disease resistance of crayfish (Procambarus clarkia). Crayfish were randomly assigned to six different boxes and two different groups in triplicate. The control group received a basal diet and the treatment group received a diet containing S. cerevisiae at 107 CFU/g. After feeding for 28 days, crayfish of the treatment group exhibited a significantly better weight gain ratio (WGR) and a specific growth rate (SGR) (p < 0.05) than crayfish of the control group. Compared to the treatment group, the control group intestines showed an oedema connective tissue layer and a weak muscle layer. For immune-related genes, Crustin2 expression was similar between the groups, whereas Lysozyme and prophenoloxidase from treatment group expression levels were upregulated significantly (p < 0.05) after 14 and 28 days of feeding. Prophenoloxidase showed the highest expression, with 10.5- and 8.2-fold higher expression than in the control group at 14 and 28 days, respectively. The intestinal microbiota community structure was markedly different between the two groups. After 14 and 28 days of feeding, the relative abundance of Cetobacterium and Lactobacillus increased, whereas Citrobacter and Bacteroides decreased in the treatment group compared with that of the control group. The challenge test showed that crayfish of the treatment group had a significantly enhanced resistance against Citrobacter freundii (p < 0.05). Our results suggest that a S. cerevisiae-containing diet positively influenced the health status, immune parameters, intestinal microbiota composition, and disease resistance of crayfish.

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
other: Publication
Adequacy of study:
weight of evidence
Study period:
2019
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
A 90‐day feeding experiment was conducted in order to test spent brewer's yeast as
a replacement for fishmeal in diets for giant freshwater prawn (Macrobrachium rosenbergii)
reared in either a recirculating aquaculture system (RAS) or a biofloc system.
Triplicate groups, each of 20 prawn (6.7 ± 0.03 g), were randomly assigned to 24
identical tanks. Twelve tanks were connected to the RAS, and the other 12 tanks
were connected to the biofloc system which were initially supplemented with Bacillus
subtilis, molasses and blood meal to achieve a C:N ratio of 20:1. Four iso‐nitrogenous
(350 g/kg) and iso‐energetic (19 MJ/kg) diets where 0%, 20%, 40% and 60% of fishmeal
protein was replaced by spent brewer's yeast.
GLP compliance:
not specified
Specific details on test material used for the study:
spent brewer's yeast was obtained from the by‐product brewery's company
Analytical monitoring:
no
Remarks:
The chemical compositions of the experimental diets were analysed in triplicate for moisture, crude protein, crude lipid, crude fibre, ash and nitrogen‐free extract (NFE) and were calculated as, NFE = 100 – (% protein + % lipid + % fibre + % ash).
Test organisms (species):
other aquatic crustacea: Macrobrachium rosenbergii
Details on test organisms:
Giant freshwater prawn
Test type:
other:
Water media type:
other:
Key result
Duration:
90 d
Dose descriptor:
other: not applicable
Nominal / measured:
not specified
Conc. based on:
test mat.
Basis for effect:
not specified
Remarks on result:
other: spent brewer's yeast represents a possible 60% substitute for fishmeal in giant freshwater prawn diets
Details on results:
Neither growth nor survival was affected (p > 0.05) by increasing levels of brewer's yeast.
Validity criteria fulfilled:
not applicable
Conclusions:
Yeast Saccharomyces cerevisiae (yeast, yeast extracts and yeast cell fraction) is also approved to be used as probiotic and as feed in invertebrates aquaculture. There is some evidence that single-cell proteins such as yeast (in particular SC) have a potential to improve feed utilization in invertebrates aquaculture. Indeed, final biomass, protein retention, efficiency and feed conversion ratio were significantly higher in aquatic invertebrates fed with SC yeast incorporated diets
Executive summary:

A 90‐day feeding experiment was conducted in order to test spent brewer's yeast as a replacement for fishmeal in diets for giant freshwater prawn (Macrobrachium rosenbergii) reared in either a recirculating aquaculture system (RAS) or a biofloc system. Triplicate groups, each of 20 prawn (6.7 ± 0.03 g), were randomly assigned to 24 identical tanks. Twelve tanks were connected to the RAS, and the other 12 tanks were connected to the biofloc system which were initially supplemented with Bacillus subtilis, molasses and blood meal to achieve a C:N ratio of 20:1. Four iso‐nitrogenous (350 g/kg) and iso‐energetic (19 MJ/kg) diets where 0%, 20%, 40% and 60% of fishmeal protein was replaced by spent brewer's yeast. Neither growth nor survival was affected (p > 0.05) by increasing levels of brewer's yeast. The exception, being fish given 60% replacement with brewer's yeast, reared in biofloc, which displayed a higher (p < 0.05) growth than fish given 40% replacement, reared in clear water. The feed conversion ratio of prawn reared in the biofloc environment was lower than in the clear water. We concluded that spent brewer's yeast represents a possible 60% substitute for fishmeal in giant freshwater prawn diets, especially for prawn reared in a biofloc environment.

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
other: Publication
Adequacy of study:
weight of evidence
Study period:
2013
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
A feeding trial was conducted for 75 days to study the effects of live brewer’s yeast Saccharomyces cerevisiae) on growth and body composition in post larvae of the giant freshwater prawn, Macrobrachium rosenbergii (de Man). Five diets were formulated containing optimum protein level of 35.24±0.04. These experimental feeds were supplemented with 0.0% (control diet), 0.1%, 0.2%, 0.5% and 1.0% live cells of S. cerevisiae.
GLP compliance:
not specified
Specific details on test material used for the study:
live brewer’s yeast
Test organisms (species):
other aquatic crustacea: Macrobrachium rosenbergii
Details on test organisms:
Macrobrachium rosenbergii de Man (Giant Freshwater Prawn)
Key result
Duration:
75 d
Dose descriptor:
other: Not applicable
Effect conc.:
0 other: Not applicable
Conc. based on:
other: Not applicable
Basis for effect:
other: Not applicable
Remarks on result:
other: Results indicated that brewer yeast can be effectively used in shrimp diets as a replacement for fish meal
Validity criteria fulfilled:
not applicable
Conclusions:
In conclusion, feeding non-indigenous S. cerevisiae through prepared feed improves growth performance, feed utilization capacity and nutritional profile of M. rosenbergii post larvae. Therefore,0.5% live S. cerevisiae can be incorporated in feed formulations for better growth performance of M.rosenbergii post larvae
Executive summary:

A feeding trial was conducted for 75 days to study the effects of live brewer’s yeast (Saccharomyces cerevisiae) on growth and body composition in post larvae of the giant freshwater prawn, Macrobrachium rosenbergii (de Man). Five diets were formulated containing optimum protein level of 35.24±0.04. These experimental feeds were supplemented with 0.0% (control diet), 0.1%, 0.2%, 0.5% and 1.0% live cells of S. cerevisiae. Weight gain, specific growth rate and protein efficiency ratio tended to increase in the postlarvae fed with either of the live yeast supplemented diets. The significant higher growth (P<0.05) performance, tissue protein, ether extract, improved specific growth rate (SGR), feed conversion ratio (FCR) was obtained in post larvae fed 0.5% of S. cerevisiae supplemented diets, suggesting that brewers yeast is an appropriate growth promoting feed additives in M.rosenbergii post larval feed.

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
other: review
Adequacy of study:
weight of evidence
Study period:
2015
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
Not applicable
GLP compliance:
not specified
Key result
Dose descriptor:
other: not applicable
Nominal / measured:
not specified
Basis for effect:
not specified
Remarks on result:
other: Review. Quantitative result was not determined. No toxicity of yeast or yeast extract is expected in all environmental compartments.
Conclusions:
Saccharomyces cerevisiae is used as probiotic for fish, and adverse effects are not foreseen from the exposure in the freshwater compartment due to the application on agricultural fields. Potential pathogenicity of Saccharomyces cerevisiae to aquatic invertebrates was indicated on a species of freshwater prawn (Macrobrachium rosenbergii). However, the actual prevalence of Saccharomyces cerevisiae in diseased prawns was very low (0.8%, only one individual out of 120 analysed). A LD50 estimation was available for intramuscular injection of Saccharomyces cerevisiae, but this exposure is not relevant for the real environment and cannot be used for risk assessment. Signs of toxicity or pathogenicity were not reported in other studies where Saccharomyces cerevisae was administered to aquatic invertebrates. Overall, the available information is considered sufficient to conclude that adverse effects are not expected on populations of aquatic invertebrates. Adverse effects are not expected for algae and aquatic plants as well.
Executive summary:

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State France for the pesticide active substance Saccharomyces cerevisiae strain LAS02 and the assessment of the application to include Saccharomyces cerevisiae strain LAS02 in Annex IV of Regulation (EC) No 396/2005, are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative use of Saccharomyces cerevisiae strain LAS02 as a fungicide on pome fruits, stone fruits, grapevine, tomato and strawberries. The reliable endpoints, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
other: Publication
Adequacy of study:
weight of evidence
Study period:
2019
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
Two 6‐week growth trials and a digestibility trial were conducted to evaluate the effects of brewer's yeast in practical shrimp feeds. In the first growth trial, graded levels (0, 60, 120, 180 and 240 g/kg) of a brewer's yeast (BY50) were used to replace fishmeal and soybean meal, referred to as Diet DBY0, DBY6, DBY12, DBY18, DBY24 and Diet LFM0, LFM6, LFM12, DBY18 and LFM24, respectively.
GLP compliance:
not specified
Specific details on test material used for the study:
Two brewers by‐products with yeast designed to contain 500 and 700 g/kg protein (BY50 and BY70) were obtained from the F.L. Emmert Company, Cincinnati, OH, USA.
Test organisms (species):
other aquatic crustacea: Litopenaeus vannamei
Details on test organisms:
Pacific white shrimp (juvenile)
Key result
Duration:
6 wk
Effect conc.:
0 other: Not applicable
Conc. based on:
other: Not applicable
Basis for effect:
other: Not applicable
Remarks on result:
other: final biomass, survival, protein retention efficiency and feed conversion ratio
Details on results:
The results showed that there were no significant differences in final biomass, survival, protein retention efficiency and feed conversion ratio; however, limited differences in final weight and weight gain were shown in the fish meal replacement series.
Validity criteria fulfilled:
not applicable
Conclusions:
Results of this study indicate that 180–240 g/kg brewer yeast can be effectively used in practical diets as a replacement for FM, or up to 240 g/kg when replacing SBM. Additionally, adding 20 g/kg of BY70 does not cause impaired growth performance for shrimp fed low‐FM diets.
Executive summary:

Two 6‐weeks growth trials and a digestibility trial were conducted to evaluate the effects of brewer's yeast in practical shrimp feeds. In the first growth trial, graded levels (0, 60, 120, 180 and 240 g/kg) of a brewer's yeast (BY50) were used to replace fishmeal and soybean meal, referred to as Diet DBY0, DBY6, DBY12, DBY18, DBY24 and Diet LFM0, LFM6, LFM12, DBY18 and LFM24, respectively. The results showed that there were no significant differences in final biomass, survival, protein retention efficiency and feed conversion ratio; however, limited differences in final weight and weight gain were shown in the FM replacement series. There was no significant difference on the growth performance in the SBM replacement series. The second growth trial was conducted with Diet DBY0, DBY12, DBY18, DBY24, LFM0 and a low‐FM diet containing 20 g/kg of BY with 700g/kg (?) protein (Diet DBY70). Shrimp fed with Diet DBY0 exhibited significantly higher final mean weight and weight gain than those offered the Diet DBY24. Nutrient availability of BY50 and BY70 was similar to SBM and significantly higher than FM. Results indicated that 180–240 g/kg BY50 can be effectively used in shrimp diets as a replacement for FM, or up to 240 g/kg when replacing SBM.

Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
other: Review
Adequacy of study:
weight of evidence
Study period:
2021
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
Not applicable
GLP compliance:
not specified
Remarks:
Review
Key result
Remarks on result:
not determinable
Remarks:
Review article
Conclusions:
The use of yeast as a sustainable protein ingredient in fish feed appear as technically feasible. Yeast is efficient in converting non-food lignocellulosic biomass to valuable products.
Executive summary:

Sustainability concerns associated with protein sources and currently used fish- meal and plant-based meal have necessitated the quests for novel sustainable ingredients for use in aquafeeds. Yeasts have been proposed as sustainable ingredients particularly because of their potential to valorise non-food lignocellulosic biomass into valuable protein resources. Prior to now, extensive studies exist on the role of yeast cell wall components in modulating health responses of fish. However, research on its use as a major protein source in fish diets is still in its infancy. The current review collates, synthesises and discusses the prospects of five major yeast species as future protein ingredients with respect to their nutritional adequacy in fish. Nutritional quality of Saccharomyces cerevisiae, Cyberlindnera jadinii, Kluyveromyces marxianus, Blastobotrys adeninivorans and Wicker- hamomyces anomalus and their use as replacement for fishmeal and soy protein in the diets of Atlantic salmon and rainbow trout are discussed based on three pro- tein quality indices: chemical score, essential amino acid index and ideal protein concept based on the first limiting amino acids, methionine. The crude protein contents of yeast (40–55%) are lower than that of fishmeal, but comparable with soya bean meal. Compared to fishmeal, the different yeast species have favourable amino acid profiles, except for methionine, lysine, arginine and phenylalanine which are the frequently limiting essential amino acids in Atlantic salmon and rainbow trout. This review also presents future area of research and emphasise the need for large-scale production of yeast at competitive price to constitute a feasible replacement for fishmeal and soy protein in aquaculture.

Description of key information

Key value for chemical safety assessment

Additional information

Saccharomyces cerevisiae which is present worldwide, has been recovered from a variety of sites under varying ecological conditions. Saccharomyces cerevisiae has an extensive history of use in the area of food processing and is used in a variety of industrial scenarios. Also known as Baker's Yeast or Brewer's Yeast, this organism has been used for centuries as leavening for bread and as a fermenter of alcoholic beverages. With a prolonged history of industrial applications, this yeast has been either the subject of or model for various studies in the principles of microbiology (EFSA,2015).
Since a few years Saccharomyces cerevisiae has been extensively used as feeding product or probiotic for a large variety of aquatic organisms (fish, crustaceans) (Agboola, 2020)
Signs of toxicity or pathogenicity were not reported in studies where Saccharomyces cerevisae or derivatives (Yeast, yeast extracts and yeast cell wall fractions) were administered to aquatic organisms. Overall, the available information is considered sufficient to conclude that adverse effects are not expected on populations of aquatic organisms other than potentially providing nutrients. (EFSA,2015; Guo, 2019; Prassad, 2013; Xu,2021; Nguyen, 2019)
Given the fact that the substance "Saccharomyces cerevisiae cell wall, extracted" shows no hazard to freshwater organisms these data emphasized , as well, on a weight of evidence basis that no long-term toxicity to aquatic invertebrates is expected for the registered substance "Saccharomyces cerevisiae cell wall, extracted" . In the absence of adverse effects, no classification is required for "Saccharomyces cerevisiae cell wall, extracted " substance according to CLP criteria.