Comparative evaluation of Brewer's yeast as a replacement for fishmeal in diets for tilapia (Oreochromis niloticus), reared in clear water or biofloc environments

Spent brewer's yeast as a replacement for fishmeal in diets for giant freshwater prawn (Macrobrachium rosenbergii), reared in either clear water or a biofloc environment

“…It also supports our assumption that the biofloc environment supported higher growth and counteracted any negative effect of graded high inclusions of brewer's yeast on growth and feed utilisation. Furthermore, exactly the same effects, using the same experimental set up, were observed in an earlier study using Tilapia ( Oreochromis niloticus ) and up to 100% replacement of fish meal by brewer's yeast (Nhi et al, ), but in that study the effect being significant ( p < 0.05), rather than in this study, only displaying trends ( p < 0.1). We believe that the discrepancy in effect between the two studies lies in the different feeding strategies of the two species, where tilapia is an excellent filter feeder, using the whole water column for foraging, while growing M. rosenbergii tend to mainly graze from solid objects as well as using their periopods (chelate legs) to bring feed particles to the mouth.…”

“…Even though several studies have indicated that brewer's yeast is a potential replacer of fishmeal in aquafeed (Essa, Mabrouk, Mohamed, & Michael, re hybrid catfish, Li & Gatlin Iii, ,, re hybrid striped bass; Rumsey, Kinsella, Shetty, & Hughes, re rainbow trout ( Oncorhynchus mykiss ), Lara‐Flores, Olvera‐Novoa, Guzmán‐Méndez, & López‐Madrid, ; Ozório, Portz, Borghesi, & Cyrino, re tilapia; Pongpet, Ponchunchoovong, & Payooha, re Thai Panga ( Pangasianodon hypophthalmus × Pangasius bocourti )), they, in parity with a number of other studies (Gumus et al, re goldfish ( Carassius auratus ); Rumsey, Hughes, & Kinsella, re lake trout ( Salvelinus namaycush ), have indicated that higher levels of replacement were associated with a tendency towards some, or even significant, reduction in growth. Neither in this or our former study using tilapia (Nhi et al, ) was any tendency of reduced growth seen in a biofloc environment with the replacement of fish meal, even if the replacement level in the present study with M. rosenbergii did not exceed 60% replacement. The rationale for not including a higher replacement level, while in the tilapia study we used up to 100% replacement of fish meal, was based on a pilot study performed in preparation for this project (personal communication Nhi Nguyen), indicating a maximum replacement for M. rosenbergii of 60% in clear water before detrimental effects on growth became apparent after a few weeks of exposure.…”

“…Even though several studies have indicated that brewer's yeast is a potential replacer of fishmeal in aquafeed (Essa, Mabrouk, Mohamed, & Michael, 2011re hybrid catfish, Li & Gatlin Iii, 2003,2004,2005 re hybrid striped bass; Rumsey, Kinsella, Shetty, & Hughes, 1991 re rainbow trout (Oncorhynchus mykiss), Lara-Flores, Olvera-Novoa, Guzmán-Méndez, & López-Madrid, 2003;Ozório, Portz, Borghesi, & Cyrino, 2012 re tilapia;Pongpet, Ponchunchoovong, & Payooha, 2016 re Thai Panga (Pangasianodon hypophthalmus × Pangasius bocourti)), they, in parity with a number of other studies (Gumus et al, 2016 re goldfish (Carassius auratus); Rumsey, Hughes, & Kinsella, 1990 re lake trout (Salvelinus namaycush), have indicated that higher levels of replacement were associated with a tendency towards some, or even significant, reduction in growth. Neither in this or our former study using tilapia (Nhi et al, 2018) L. vannamei in BFT allowed the protein level of the diet to be reduced with as much as 29% and 48%, respectively, compared to rearing in clear water. These results tally well with our study in such that the BFT are able to provide additional protein.…”

“…However, to our knowledge few or no studies in freshwater shrimp have, under controlled experimental conditions, combined yeast‐based protein and biofloc environment, to evaluate if these two measures display synergy compared to being applied individually. Based on our earlier work in tilapia (Nhi, Da, Lundh, Lan, & Kiessling, ), it is our assumption that if applied correctly, biofloc could compensate for an inferior protein source or a reduced dietary protein level. In this study, we, therefore, investigated whether M. rosenbergii reared in a biofloc system displayed an improved ability when fed a diet supplemented with brewer's yeast as a protein source, replacing fishmeal, with maintained growth performance, survival rate, feed conversion ratio and feed utilization.…”

“…However, to our knowledge few or no studies in freshwater shrimp have, under controlled experimental conditions, combined yeast-based protein and biofloc environment, to evaluate if these two measures display synergy compared to being applied individually. Based on our earlier work in tilapia (Nhi, Da, Lundh, Lan, & Kiessling, 2018), it is our assumption that if applied correctly, biofloc could compensate for an inferior protein source or a reduced dietary protein level.…”