Saccharomyces cerevisiae cell wall, extracted

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to fish, other

Type of information:

other: Publication

Adequacy of study:

weight of evidence

Study period:

2019

Reliability:

2 (reliable with restrictions)

Qualifier:

no guideline required

Principles of method if other than guideline:

Long-term effects of three dietary probiotics on rainbow trout during grow-out (mean body weight =250±50g) were investigated by feeding for 130 days on eight diet treatments supplemented with Lactobacillus buchneri, L. fermentum and Saccharomyces cerevisiae as singularly or in combination.

GLP compliance:

no

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Rainbow trout at grow- out stage (with an average weight of 250 ± 50 g)

Key result

Dose descriptor:

other: not applicable

Basis for effect:

other: Growth parameters, Hematological parameters, Respiratory burst activity, Serum biochemical parameters

Remarks on result:

other: none of the probiotic treatments had a significant effect on trout growth performance, or total protein, albumin, globulin, triglyceride and the red blood cell count after 30 or 130 days.

Validity criteria fulfilled:

not applicable

Conclusions:

In conclusion, our results demonstrated that long- term dietary administration of probiotics to rainbow trout during grow-out as a single treatment improved the FCR and immunity, including the expression of cytokine genes and WBC counts. There was no synergistic effect by delivering the three probiotics in combination. S. cerevisiae showed the highest immunostimulatory effect when administered in isolation and therefore we recommend using this probiotic to achieve higher immunity status in fish to improve the response to disease and environmental stresses. Extended periods of delivery of probiotics are likely to increase the beneficial effects.

Executive summary:

The long-term effects of three dietary probiotics on rainbow trout during grow-out (mean body weight = 250 ± 50 g) were investigated by feeding for 130 days on eight diet treatments supplemented with Lactobacillus buchneri, L. fermentum and Saccharomyces cerevisiae at 107 CFU/g, singularly or in combination. Fish samples were taken for biochemical and immunological analysis in addition to growth performance indices at days 30 and 130 of the experiment. The expression levels of TNF-α and IL-1β genes were also measured at day 130. A positive effect on food conversion was observed in rainbow trout with dietary inclusion of S. cerevisiae (P < 0.05) over 130 days. Also, the total number of white blood cells and their differential count (blood neutrophils, lymphocytes and monocytes), as well as respiratory burst activity were all significantly affected by different treatments at 130 days (P < 0.05). Moreover, at 130 days there was a significant increase in the expression of TNF-α and IL-1β in yeast present treatment compared to the control group (P < 0.05), but no significant difference in the combined probiotic treatments from control group. Yeast and L. buchneri showed a contrary effect on the immune gene expression regulation. Serum cholesterol was significantly lower in all treatments receiving yeast as a dietary probiotic, either alone or in combination with other probiotics. However, none of the probiotic treatments had a significant effect on trout growth performance, or total protein, albumin, globulin, triglyceride and the red blood cell count after 30 or 130 days. Overall, the results suggest that inclusion of a single dietary probiotic, especially S. cerevisiae, in rainbow trout during grow-out has a greater positive effect than combinations of probiotics on the immune system.

Reference 2

Endpoint:

long-term toxicity to fish, other

Type of information:

other: Review

Adequacy of study:

weight of evidence

Study period:

2015

Reliability:

2 (reliable with restrictions)

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:

Yeast Saccharomyces cerevisiae is ubiquitous in nature and naturally occurring in all environmental compartments and animals. No toxicity of yeast or yeast extract is expected in all environmental compartments.

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.

Reference 3

Endpoint:

long-term toxicity to fish, other

Type of information:

other: Publication

Adequacy of study:

weight of evidence

Study period:

2019

Reliability:

2 (reliable with restrictions)

Principles of method if other than guideline:

the effect of graded levels of dietary inactivated brewer's yeast, Saccharomyces cerevisiae, on the growth performance and hemobiochemical parameters of dusky kob in a 6-week feeding period.

GLP compliance:

not specified

Specific details on test material used for the study:

Commercial brewer's yeast product (inactivated S. cerevisiae) was sourced from a health food distributor, Nature's Choice, based in Meyerton, South Africa

Test organisms (species):

other: Argyrosomus japonicus

Details on test organisms:

dusky kob

Key result

Duration:

6 wk

Dose descriptor:

other: not applicable

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: the maximum inclusion level of brewer's yeast that does not impair growth performance and health of dusky kob is 50 g/kg.

Conclusions:

In conclusion, the current study demonstrated that supplementation with brewer's yeast at levels above 50 g/kg could be detrimental to the growth of the South African dusky kob. The use of a probiotic mix did not yield any positive influence on fish growth; hence, it may not be beneficial in dusky kob diets. For uncompromised growth performance, future dusky kob diets may include up to 50 g brewer's yeast/kg kob feed.

Executive summary:

 

There is some evidence that single-cell proteins such as yeast have the potential to improve feed utilization in aquaculture fish, but this has not been investigated in the economically important dusky kob, Argyrosomus japonicus. This study was, therefore, designed to determine the effect of graded levels of dietary inactivated brewer's yeast, Saccharomyces cerevisiae, on the growth performance and hemobiochemical parameters of dusky kob in a 6-week feeding period. Five isonitrogenous and isoenergetic diets—consisting of three brewer's yeast-containing diets at rates of 50,150, and 300 g/kg dry matter (BY5P0, BY15P0, and BY30P0, respectively); a commercial dusky kob diet containing 10% probiotic mix but no brewer's yeast (BY0P1, positive control); and a commercial dusky kob diet with neither the probiotic mix nor the yeast (BY0P0, negative control)— were formulated. A total of 65 fish, weighing an average of 7.02 ± 0.10 g, were randomly distributed to each of 20 replicate tanks. Each dietary treatment was randomly allocated to four tanks and offered to fish at a rate of 2.8% fish body weight per day. A total of 10 fish from each tank were randomly sampled once a week for length and weight measurements. Blood was drawn from five fish per tank (20 fish per treatment) for hematology and serum biochemical analyses at the end of the 6 weeks. Fish on the BY0P0 diet achieved the highest weight gain of 18.53 ± 0.69 g after 6 weeks. Growth rate was significantly reduced in the groups fed BY15P0 and BY30P0 diets compared to the BY0P0, BY0P1, and BY5P0 groups. Fish fed the BY0P0 diet recorded the highest average feed conversion efficiency (FCE) of 0.22, while the BY30P0-fed group recorded the lowest FCE of 0.15. Hematocrit and alanine transaminase levels declined with increasing levels of yeast. It can be concluded that the maximum inclusion level of brewer's yeast that does not impair growth performance and health of dusky kob is 50 g/kg.

 

Reference 4

Endpoint:

long-term toxicity to fish, other

Type of information:

other: Publication

Adequacy of study:

weight of evidence

Study period:

2020

Reliability:

2 (reliable with restrictions)

Qualifier:

no guideline required

Principles of method if other than guideline:

effects of commercially available baker’s yeast as feed additive on growth performance, feed utilization and disease resistance in freshwater catfish Mystus cavasius. Fish fry (0.5 ± 0.2 g) were randomly distributed into twelve glass aquaria (65 L) at a stocking density of 15 fish per aquarium. Fish were fed an experimental diet containing 0 (control, T1), 0.5 (T2), 1.0 (T3), 1.5 (T4) g yeast/kg diet for 75 days.

GLP compliance:

no

Specific details on test material used for the study:

Baker’s yeast

Test organisms (species):

other: Mystus cavasius

Details on test organisms:

freshwater catfish

Key result

Duration:

75 d

Dose descriptor:

other: not applicable

Basis for effect:

other: growth performance

Remarks on result:

other: the result of the experiment showed that the growth performance of gulsa tengra in terms of final body weight, weight gain, percent weight gain, and specific growth rate was significantly (P < 0.05) higher in T3 which contained 1.0 g yeast/kg commercial

Executive summary:

This study was carried out to evaluate the effects of commercially available baker’s yeast as feed additive on growth performance, feed utilization and disease resistance in freshwater catfish Mystus cavasius. Fish fry (0.5 ± 0.2 g) were randomly distributed into twelve glass aquaria (65 L) at a stocking density of 15 fish per aquarium. Fish were fed an experimental diet containing 0 (control, T₁), 0.5 (T₂), 1.0 (T₃), 1.5 (T₄) g yeast/kg diet for 75 days. After this period, fish of each treatment were challenged against fish pathogenic bacteria Pseudomonas fluorescens and the mortality rate was recorded for a week. Growth parameters (survival rate, weight gain, specific growth rate, and protein efficiency ratio) were significantly (P < 0.05) increased in fish treated with experimental diets T₂, T₃ and T₄ compared to control T₁. Weight gain (436.36%), condition factor (1.92 ± 0.03), specific growth rate (2.23 ± 0.04), and protein efficiency ratio (0.48 ± 0.05) were significantly highest in T₃ than other treatments. The feed conversion ratio was significantly decreased in T₃ treatment (P < 0.05). The lowest fish mortality rate (10%) was observed in the challenged fish of T₃ treatment which was fed with 1.0 g yeast/kg diet. The results indicated that yeast supplement is a promising growth promoter and might be an alternative method to antibiotics for disease prevention of M. cavasius.

Reference 5

Endpoint:

long-term toxicity to fish, other

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:

other: not determinable 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.

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 (east, 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; Banu, 2020; Vazirzadeh, 2019; Miao,2020; Madibana, 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 fish 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.