Torula yeast in the diet of Atlantic salmon Salmo salar and the impact on growth performance and gut microbiome

Atlantic salmon aquaculture is expanding, and with it, the need to find suitable replacements for conventional protein sources used in formulated feeds. Torula yeast (Cyberlindnera jadinii), has been identified as a promising alternative protein for feed and can be sustainably cultivated on lignocellulosic biomasses. The present study investigated the impact of torula yeast on the growth performance and gut microbiome of freshwater Atlantic salmon. A marine protein base diet and a mixed marine and plant protein base diet were tested, where conventional proteins were replaced with increasing inclusion levels of torula yeast, (0%, 10%, 20%). This study demonstrated that 20% torula yeast can replace fish meal without alteration to growth performance while leading to potential benefits for the gut microbiome by increasing the presence of bacteria positively associated with the host. However, when torula yeast replaced plant meal in a mixed protein diet, results suggested that 10% inclusion of yeast produced the best growth performance results but at the 20% inclusion level of yeast, potentially negative changes were observed in the gut microbial community, such as a decrease in lactic acid bacteria. This study supports the continued investigation of torula yeast for Atlantic salmon as a partial replacement for conventional proteins.

Field response of three Tephritid fruit flies to three food-based attractants and suppression of Bactrocera zonata (Saunders) using Mazoferm–Spinosad in guava ecosystem in Sudan

Fruit flies of the genus Bactrocera are the most damaging pests of horticultural crops, leading to severe economic losses hindered exportation. Bactrocera dorsalis (Hendel) and Bactrocera zonata (Saunders) were reported in Sudan in 2005 and 2011 respectively affecting most of the fruits and vegetables in Sudan threatening income of poor farmers. Only Male Annihilation Technique (MAT) is applied in Sudan to manage the two Bactrocera species. A filed experiment was conducted to evaluate the response of B. dorsalis, B. zonata and Zeugodacus cucurbitae to three food-based attractants using McPhail traps in two sites in Gezira state, Sudan. Also, other trial was undertaken to determine the effect of spray of Mazoferm and Spinosad combination to control B. zonata. The results showed that food-based attractants lured both sexes of the above mentioned fruit flies and females represented (55-86%). At the first site, B. zonata responded in high numbers to Mazoferm followed by Torula yeast and GF-120 respectively while it responded equally to the Mazoferm and Torula yeast in the second site. B. dorsalis responded positively to Mazoferm followed by Torula yeast and GF-120 while Z. cucurbitae was attracted to Mazoferm, GF-120 and Torula for each attractant respectively. Spray of Mazoferm combined with Spinosad significantly reduced population of B. zonata (FTD) population and suppressed infestation level of guava fruits (fruit flies/Kg of fruits) when compared to unsprayed orchard. Bait Application Technique is an environmentally friendly approach that reduces infestation levels, lessen contamination and safeguard produce.

Preferential Attraction of Oviposition-Ready Oriental Fruit Flies to Host Fruit Odor over Protein Food Odor

Olfaction plays a key role in the location of food and oviposition resources by tephritid fruit flies. Adult females, including oriental fruit fly, Bactrocera dorsalis, can sustain egg production throughout their lives provided they obtain sufficient protein. Thus, preferential attraction to food or oviposition sites (host fruit) will depend on a fly’s particular physiological state. In this study, laboratory bioassays were conducted with mature, mated B. dorsalis (provisioned protein and sugar ad libitum) to evaluate attraction to traps baited with torula yeast versus six host fruit sources (guava, guava juice, mango, orange, Surinam cherry, or white sapote). Females that preferred fruit laid a significant number of eggs around the trap entrance (average 405 eggs/fly), while almost no eggs were laid by females that preferred yeast (0.5 and 1.3 eggs/fly on two occasions). Similar results were observed in a bioassay using headspace extracts of guava juice and torula yeast, supporting olfactory-mediated responses. When individual females were allowed to oviposit in guava juice traps 0–24 h after a choice test, 45.8% of females that chose guava juice laid eggs (average 14.7 eggs/fly), compared with 27.5% that chose yeast (average 6.5 eggs/fly). Dissections indicated that females with a preference for guava juice had an egg load 2.4 times greater than females that preferred yeast. These results suggest there is an olfactory-based behavioral switch in preference from protein to host odors when female B. dorsalis are oviposition-ready. We discuss the implications of our findings for practical behavioral management and detection programs for B. dorsalis.

Torula Yeast in the Diet of Atlantic Salmon Salmo Salar and the Impact on Growth Performance and Gut Microbiome.

Atlantic salmon aquaculture is expanding, and with it, the need to find suitable replacements for conventional protein sources used in formulated feeds. Torula yeast (Cyberlindnera jadinii), has been identified as a promising alternative protein for feeds and can be sustainably cultivated from lignocellulosic biomasses. The present study investigates the impact of torula yeast on the growth performance and the gut microbiome of freshwater Atlantic salmon. Both a marine protein base diet and a mixed marine and plant protein base diet were tested, where conventional proteins were replaced with increasing inclusion levels of torula yeast, (0%, 10%, 20%). This study demonstrated that 20% torula yeast can replace fish meal without alteration to growth performance while leading to potential benefits for the gut microbiome by increasing the presence of bacteria positively associated with the host. However, when torula yeast replaced plant meal in a mixed protein diet, results suggest 10% inclusion of yeast produced the best growth performance results and at the highest inclusion level, potentially negative changes were observed in the gut microbial community, such as a decrease in lactic acid bacteria. This study supports the continued investigation of torula yeast for Atlantic salmon as a partial replacement for conventional proteins.

Torula Yeast in the Diet of Atlantic Salmon Salmo Salar and the Impact on Growth Performance and Gut Microbiome.

BackgroundLarge scale Atlantic salmon (Salmo salar) aquaculture is expanding, and with it, the need to find suitable replacements of conventional protein sources used in formulated feeds. Torula yeast (Cyberlindnera jadinii) has been identified as a promising alternative protein for aquaculture feeds, and can be sustainable cultivated from lignocellulosic biomasses, contributing to circular economic growth. The present study aimed to investigate the impact of torula yeast on the growth performance and the gut microbiome of freshwater Atlantic salmon to facilitate the commercial uptake of this alternative protein. Two types of diets were assessed in this study. Firstly, a marine protein base diet where fish meal (FM) was replaced with increasing inclusion levels of torula yeast, (0%, 10%, 20%) to provide a simplified replacement. Secondly, a marine protein and plant protein combination where mixed plant meals (MIX) were replaced with increasing inclusion levels of torula yeast, (0%, 10%, 20%) to provide a commercial relevant dietary replacement.ResultsThis study demonstrated that 20% torula yeast can replace fish meal without alteration to the growth performance while leading to potential benefits for the gut microbiome by increasing the presence of bacteria positively associated with the host. However, when torula yeast replaced a mix of plant meal in a combined protein source diet results suggest 10% inclusion of yeast produced the best growth performance results compared with both the control and 20% inclusion. At the highest inclusion level for the mixed diets potentially negative changes were observed in the gut microbial community, such as a decrease in lactic acid bacteria and an increased level of bacteria associated with slower growth in other salmonid species.ConclusionsThis study supports the application of torula yeast in the diet of Atlantic salmon as a partial replacement for conventional protein sources. However, the other components of the diet will need to be considered to determine the optimal inclusion level for this alternative protein. Future research should further optimise the inclusion of torula yeast in salmonid diets and investigate its influence on the functional role of the fish gut microbiome to facilitate improved formulated feed formulations and ensure a sustainable development of the aquaculture industry.

Does Ammonia Released from Protein-Based Attractants Modulate the Capture of Anastrepha obliqua (Diptera: Tephritidae)?

Tephritid fly responses to food-based attractants involve a complex range of food-derived semiochemicals, including ammonia. We performed laboratory and field experiments to compare the attraction of Anastrepha obliqua (Macquart) to ammonia with the attraction to commercial food attractants and torula yeast at a range of pHs. A positive correlation was established between the concentration of ammonia in solution (1.5–150 mM ammonium solution) and gaseous ammonia released by bottle-type traps. This resulted in an asymptotic response in captures of A. obliqua flies in traps that released 99–295 µg ammonia/h. Pairwise comparisons in laboratory cages revealed that traps baited with 150 mM ammonia solution captured similar numbers of A. obliqua as traps baited with Biolure 2C, CeraTrap, and hydrolyzed protein products (Captor, Winner, and Flyral) plus borax, despite the low quantities of ammonia (11–56 µg/h) released from these attractants. Subsequent choice experiment captures in traps containing ammonia solution were similar or higher than those of commercial attractants, with the exception of Winner + borax, but were not correlated with the ammonia released from attractants. Captures of flies in traps containing ammonia solution were increased by the addition of 1% torula yeast or torula yeast alkalized with sodium hydroxide or borax despite differences in the quantities of ammonia released. Fly captures generally increased with increasing alkalization of torula yeast (pH 7.5–9.5). In the field, torula yeast in ammonia solution captured similar numbers of A. obliqua flies as Captor + borax when traps were evaluated after 24 h but not after a 7-day trapping period. Traps baited with ammonia solution or Winner + borax were significantly less attractive than Captor + borax in both field experiments. We conclude that A. obliqua flies are attracted to ammonia solutions of increasing concentration, up to 150 mM, in the absence of other stimuli, whereas attraction to commercial attractants or alkalized torula yeast is not correlated with the release of ammonia.

166 Enhanced torula yeast has increased nutritional value compared to fish meal when fed to weanling pigs

The hypothesis that the standardized ileal digestibility (SID) of AA, concentration of ME, and the standardized total tract digestibility (STTD) of P in an enhanced torula yeast (ETY; Arbiom, Raleigh, NC) are not different from values obtained in Menhaden fish meal (FM) was tested. In Exp. 1, 6 ileal cannulated barrows (11.7 ± 0.4 kg) were allotted to a replicated 3 × 3 Latin square with 3 diets (ETY, FM, and N-free) and 3 7-d periods. Ileal digesta were collected on d 6 and 7 of each period. Data were analyzed using the Proc Mixed with diet as main effect and pig as random effect. The SID of AA was greater (P < 0.05) in ETY than in FM (Table 1). In Exp. 2, 24 barrows (14.4 ± 1.1 kg) were individually housed in metabolism crates and allotted to a corn diet or diets based on corn and ETY or corn and FM. Feces and urine were collected for 5 d. Data were analyzed as in Exp. 1. No difference in ME between ETY (3,636 kcal/kg DM) and FM (3,611 kcal/kg DM) was observed. In Exp. 3, 32 barrows (11.9 ± 1.1 kg) were allotted to 4 diets in a 2 × 2 factorial with 2 ingredients (ETY and FM) and 0 or 500 units/kg of phytase. Housing and fecal sample collection was as in Exp. 2. Data were analyzed as in Exp. 1 with diet and phytase as main effects. Phytase did not influence STTD of P, but the STTD of P in the ETY (91%) was greater (P < 0.05) than in FM (68%). In conclusion, the SID of AA and the STTD of P in ETY is greater than in FM, but the ME in ETY is not different from FM.

Yeasts Associated with the Olive Fruit Fly Bactrocera oleae (Rossi) (Diptera: Tephritidae) Lead to New Attractants

The olive fruit fly (Bactrocera oleae Rossi) is the primary insect pest in all olive-growing regions worldwide. New integrated pest management (IPM) techniques are needed for B. oleae to mitigate reliance on pesticides used for its control which can result in negative environmental impacts. More effective lures for monitoring olive flies would help to know when and where direct chemical applications are required. The aim of this research was to find new, more effective methods for B. oleae detection and monitoring. Twelve insect-associated yeasts were selected and tested as living cultures in McPhail traps for the attraction of olive flies. Certain yeasts were more attractive than others to B. oleae; specifically, Kuraishia capsulata, Lachancea thermotolerans, Peterozyma xylosa, Scheffersomyces ergatensis, and Nakazawae ernobii, than the industry-standard dried torula yeast (Cyberlindnera jadinii; syn. Candida utilis). The attractiveness of dry, inactive (i.e., non-living) formulations of these five yeasts was also tested in the field. Inactive formulations of K. capsulata, P. xylosa, N. ernobii, and L. thermotolerans were significantly more attractive to B. oleae than commercially available torula yeast. Green lacewing, Chrysoperla comanche (Stephens) (Neuroptera: Chrysopidae), adults were incidentally caught in traps baited with the live yeast cultures. This is the first field study that compares olive fly attraction to yeast species other than torula yeast. Commercialization of yeasts that are more attractive than the torula standard would improve monitoring and associated control of the olive fruit fly.

Effect of torula yeast on growth performance, diarrhea incidence, and blood characteristics in weanling pigs

Two experiments were conducted to test the hypothesis that torula yeast may replace animal and plant proteins in diets for weanling pigs without negatively impacting growth performance or blood characteristics. In exp. 1, 128 weanling pigs (6.71 ± 0.76 kg) were allotted to four treatments with four pigs per pen and eight replicate pens per diet. Pigs were fed one of four diets from day 1 to 14 post-weaning (phase 1), whereas all pigs were fed a common diet in phase 2 (day 15 to 28). The four dietary treatments included a control diet with 5% fish meal, 2.5% plasma protein, and no torula yeast. The second diet contained 5% fish meal, 4.75% torula yeast, and no plasma protein. The third diet contained 2.5% plasma protein, 6% torula yeast, and no fish meal, and the last diet contained 10.75% torula yeast, no fish meal, and no plasma protein. The inclusion of torula yeast was calculated to replace the amount of digestible Lys provided by fish meal, plasma protein, or both fish meal and plasma protein in the control diet. During the initial 14 d, fecal scores were visually assessed. At the end of phase 1, blood samples were collected and tumor necrosis factor-α (TNF-α), blood urea nitrogen (BUN), peptide YY, immunoglobulin G, total protein, and albumin were analyzed. Results indicated that torula yeast could replace fish meal and plasma protein without affecting growth performance, fecal scores, or blood characteristics of pigs. In exp. 2, 160 weanling pigs (6.11 ± 0.62 kg) were allotted to one of four diets with five pigs per pen and eight replicate pens per diet. Phase 1 diets contained 0%, 10%, 18%, or 26% torula yeast, whereas phase 2 diets contained 0%, 8%, 14%, or 20% torula yeast. Torula yeast was included in diets at the expense of animal proteins and soybean meal. On days 14 and 28, blood samples were collected and concentrations of cytokines, BUN, total protein, and albumin were analyzed. Phase 2 gain-to-feed ratio (G:F) linearly increased (P < 0.01) as the concentration of torula yeast increased in the diets. The concentration of albumin on day 14 linearly increased (P < 0.05) and the concentration of TNF-α was linearly reduced (P < 0.01) as the concentration of torula yeast increased in the diets. In conclusion, under the conditions of this research, torula yeast could replace fish meal and plasma protein without affecting the growth performance of pigs, but inclusion of increasing levels of torula yeast improved G:F of pigs, which may be because of greater nutrient utilization.