Effect of two insect meals on the gut commensal microbiome of healthy sea trout (Salmo trutta vr. trutta).

BACKGROUND: The balance of the intestinal commensal microbiome of fish and other animals plays an important role in the physiological processes of healthy animals, contributes to the defense against pathogens, stimulates the immune system and facilitates nutrient metabolism. In the last decade, the interest in the application of the insects in fish nutrition increased, although little is known regarding the effects of insect meals on the gastrointenstinal tract microbiome of the sea trout fingerlings. The aim of this study was to evaluate the effect of two diets containing mealworm (MW) and superworm (SW) on the microbiome of the digesta of sea trout fingerlings and the relative abundances of different taxa among communities under controlled conditions. RESULTS: The insect meals produced a similar weight gain and survival rate to sea trout fed fishmeal. The most abundant bacterial phylum in all the treatment groups was Firmicutes followed by Proteobacteria and Actinobacteria, and significant differences in the amount of Cyanobacteria were observed in the SW group. CONCLUSIONS: The insect meals did not produce differences in the three most abundant phyla in the sea trout digesta. However, the effect of each type of meal on the lower taxonomic levels was evident, particularly in the case of the superworm meal. These microbiome differences indicated that mealworm meal was more related to fishmeal than superworm meal. Our results highlight the potential effects of insect meals, such as mealworm and superworm meals, on the microbiota of sea trout.

Black Soldier Fly Larva Fat in Broiler Chicken Diets Affects Breast Meat Quality.

This study aimed to evaluate the dose-dependent effect of black soldier fly (BFL) larvae fat inclusion in broiler chicken diets on breast meat quality. Four hundred 1-day-old male birds (Ross 308) were assigned to the following four treatments (10 replicates with 10 birds each): HI0, a basal diet without dietary fat inclusion, and HI03, HI06, and HI09, basal diets enriched with 30 g/kg, 60 g/kg, and 90 g/kg of BSF larvae fat, respectively. Principal component analysis showed noticeable differentiation between the selected plant, animal, and insect-origin dietary fats. The BSF fat exhibits a strong relationship with saturated fatty acids (SFAs), resulting in a high concentration of C12:0 and C14:0. The fatty acid (FA) profile in breast muscle obtained from broilers fed diets with increasing insect fat inclusion showed a significant linear effect in terms of C12:0, C15:0, C18:2, C18:3n6, and total FAs. The proportion of dietary insect fat had a quadratic effect on meat color. The water-holding capacity indices have stayed consistent with the meat color changes. Throughout the experiment, favorable growth performance results were noticed in HI06. The present study confirmed that BSF larvae fat negatively affects the n3 level in meat. However, the physicochemical indices related to consumer acceptance were not altered to negatively limit their final decision, even when a relatively high inclusion of insect fat was used.

Available for millions of years but discovered through the last decade: Insects as a source of nutrients and energy in animal diets.

The aim of this review is to present and discuss the most recent literature about the processing of insect biomass and its impact on nutritive value, further implementation of meals and fats derived from invertebrates to livestock (poultry and swine), aquaculture (salmonids), and companion animal diets and their impact on growth performance, metabolic response, and gastrointestinal microbiota shifts. Additionally, the most important barriers to obtaining unified products in terms of their nutritive value are considered, i.e., to define insects' nutrient requirements, including various technological groups and further biomass processing (slaughtering, drying, and storage). Due to the current limitation in the insect production process consisting of the lack of infrastructure, there is stress on the relatively small amount of insect products added to the animal diets as a functional feed additive. Currently, only in the case of pet nutrition may insects be considered a full replacement for commonly used environmentally harmful and allergenic products. Simultaneously, the least information has been published on this topic. Thus, more scientific data are needed, particularly when the pet food branch and insect-based diets are rapidly growing.

Dietary Fish Meal Replacement with Hermetia illucens and Tenebrio molitor Larval Meals Improves the Growth Performance and Nutriphysiological Status of Ide (Leuciscus idus) Juveniles.

The ide (Leuciscus idus) is a native European species of rheophilic cyprinid fish whose wild population status is dependent on conservation efforts, particularly regular restocking. This study aimed to evaluate the effects of including insect meals as a component in the diet of ide juveniles on their growth performance, feed utilization, and nutriphysiological status. Four diets were formulated: three with insect meals, HI-with 20% Hermetia illucens meal, TM-with 20% Tenebrio molitor meal, and ZM-with 20% Zophobas morio meal, and the control group diet, CON-fish meal with no insect component. The effects of the various diets on the efficiency of rearing ide juveniles were assessed based on fish growth parameters, feed utilization parameters, somatic indices, and intestinal and hepatopancreatic histomorphology. The highest increase in fish weight gain and the protein efficiency ratio was observed in the HI and TM groups, while the lowest values were observed in the CON and ZM groups. Comparable results were noted for the feed conversion ratio, which was most favorable in the HI and TM groups and increased in the ZM group. The use of black soldier fly and mealworm larval meal in the diets of ide juveniles had a positive effect on rearing results and overall fish health.

A Preliminary Study of Chemically Preserved and High-Moisture Whole Maize (Zea mays L.) Usage in Pekin Duck Nutrition: Effect on Growth Performance and Selected Internal Organ Traits.

This study aimed to investigate the effect of chemically preserved, high-moisture whole maize grain addition in Pekin duck diets on their growth performance and selected internal organ and gastrointestinal tract measurements and digesta pH values. A total of 300 29-d-old male Pekin ducks were randomly distributed into three dietary treatments using five replicate pens per group and 20 birds per pen. The following treatment groups were applied: CON-basal diet, 5HM-5% of high-moisture, chemically preserved whole maize (HM) inclusion, and 10HM-10% of HM addition. The experiment lasted 21 d. The implementation of 5HM or 10HM did not affect (p > 0.05) the growth performance parameters, selected internal organ weights, and the gastrointestinal tract segment weights and lengths. However, significant changes in terms of the gizzard (p = 0.005), ileum (p = 0.030), and caecal (p < 0.001) digesta pH were observed, especially in the case of the 10HM group, which exhibited the greatest increase in pH in the gizzard and caecal digesta and decrease in the ileal digesta pH. The implementation of whole wet maize may be used in waterfowl diets from 29 d of age. Additionally, chemical preservation can efficiently reduce the cost of maize preparation in duck nutrition.

Black Soldier Fly Full-Fat Larvae Meal is More Profitable than Fish Meal and Fish Oil in Siberian Sturgeon Farming: The Effects on Aquaculture Sustainability, Economy and Fish GIT Development.

This study provides data on the environmental sustainability, economic profitability, and gastrointestinal tract development of Siberian sturgeon diets containing black soldier fly full-fat larvae meal (BSFL) for a fish meal (FM) and fish oil (FO) replacement. BSFL was used at 5%, 10%, 15%, 20%, 25%, and 30% of the diet, replacing by up to 61.3% of FM and 95.4% of FO. BSFL positively affected the feed efficiency ratio, and lowered FM and FO usage per kg of fish gain. All the BSFL diets showed a sustainable fish-in fish-out (FIFO) ratio, which was lowered by up to 75% in comparison to the control. Economic assessment per kg of fish gain showed that the most lucrative variants were variants with 10% and 15% BSFL, it finds a mode of action in improvements of the gastrointestinal tract development, including increased pyloric caeca and proximal intestine shares and enhanced villus height and area. Thus, in Siberian sturgeon, BSFL may be used not only as an FM and FO replacer but also as a functional material due to its feed utilization and beneficial health effects, which are reflected in its high sustainability and favourable economics.

Effects of Raw and Fermented Rapeseed Cake on Growth Performance, Methane Production, and Breast Meat Fatty Acid Composition in Broiler Chickens.

The study was conducted to evaluate the effects of partial replacement of soybean meal (SBM) by 15% raw or fermented rapeseed cake (RRC or FRC) to broilers' diets on growth performance, nutrient utilization, methane emission, and breast muscle fatty acid (FA) composition. A total of 420 one-day-old female Ros 308 broilers were used in three independent experiments (300 birds in the first experiment and 60 in the second and third experiments). In each trial, three treatments were set up: a control group (without rapeseed), and diets replaced soybean meal with 15% addition of RRC or FRC. Birds fed the FRC diet experienced no effect (p > 0.05) on performance or nutrients utilization. Methane emission and total methanogen population in the ceca was decreased (p < 0.05) with the FRC diet. The concentrations of n-3 and n-6 FAs in the breast tissue of fourteen-day-old birds were not affected (p > 0.05) by FRC. However, the n-6/n-3 ratio in the breast muscle of 28-day-old birds was reduced (p < 0.001). In conclusion, the replacement of SBM by FRC in the broiler diets did not show any unfavorable effects on performance or nutrient utilization. Furthermore, the breast meat FA profile was improved, methanogen counts significantly decreased, and methane emission was limited.

Black Soldier Fly Full-Fat Larvae Meal as an Alternative to Fish Meal and Fish Oil in Siberian Sturgeon Nutrition: The Effects on Physical Properties of the Feed, Animal Growth Performance, and Feed Acceptance and Utilization.

This study provides data on the use of black soldier fly (Hermetia illucens) full-fat meal (BSFL) in Siberian sturgeon (Acipenser baerii) nutrition, examining pellet physical properties, growth performance, feed acceptance and utilization, apparent protein, and fat digestibility. The study consisted of: feed quality assessment; a growth performance; feed acceptance; digestibility trials. The effect of the use of BSFL as a replacement for fish meal (FM) and fish oil (FO) was investigated. The applied BSFL shares were 5%, 10%, 15%, 20%, 25%, and 30% of the diet, replacing up to 61.3% of FM and allowing us to reduce FO use by up to 95.4% in the case of 30% incorporation. The applied substitution affected feed quality, increasing the expansion rate, and decreasing feed density, sinking speed and water stability. However, body weight gain, specific growth rate, feed, and protein conversion ratios, were improved in groups fed BSFL. Moreover, feed acceptance was increased with treatments containing 10 to 30% BSFL. No effects on nutrients digestibility were observed. The results show that the use of BSFL as an FM and FO replacement may have positive effects on sturgeon growth performance, and BSFL can be developed as a promising alternative feed material.

The Effect of Hydrolyzed Insect Meals in Sea Trout Fingerling (Salmo trutta m. trutta) Diets on Growth Performance, Microbiota and Biochemical Blood Parameters.

The present study is the first introduction of hydrolyzed superworm meal in sea trout nutrition. It was conducted to evaluate the effects of inclusion in the diet of hydrolyzed insect meals as a partial replacement for fishmeal on growth performance, feed utilization, organosomatic indices, serum biochemical parameters, gut histomorphology, and microbiota composition of sea trout (Salmo trutta m. trutta). The experiment was performed on 225 sea trout fingerlings distributed into three groups (3 tanks/treatment, 25 fish/tank). The control diet was fishmeal-based. In the experimental groups, 10% of hydrolyzed mealworm (TMD) and superworm (ZMD) meals were included. The protein efficiency ratio was lower in the TMD and ZMD. Higher organosomatic indices and liver lipid contents were found in the group fed ZMD. The ZMD increased levels of aspartate aminotransferase, and decreased levels of alkaline phosphatase. The Aeromonas spp. and Enterococcus spp. populations decreased in the ZMD. The concentrations of the Carnobacterium spp. decreased in the ZMD and TMD, as did that of the Lactobacillus group in the TMD. In conclusion, insect meals may be an alternative protein source in sea trout nutrition, as they yield satisfying growth performance and have the capability to modulate biochemical blood parameters and microbiota composition.

Combination of Bacillus licheniformis and Salinomycin: Effect on the Growth Performance and GIT Microbial Populations of Broiler Chickens.

The aim of the study was to investigate the effect of Bacillus licheniformis and salinomycin supplementation in broiler diets as individual factors or in combination on the growth performance, GIT morphometry, and microbiota populations. Four hundred one-day-old Ross 308 chicks were randomly distributed to four dietary treatments (10 replicates, 10 birds each). The following treatments were applied: NC-no additives; NC + SAL-salinomycin addition (60 mg/kg diet), NC + PRO-B. licheniformis DSM 28710 preparation (1.6 × 109 CFU/kg; 500 mg/kg diet), and NC + SAL + PRO-combination of salinomycin and B. licheniformis. Probiotic administration resulted in improvement (p < 0.05) of the performance parameters, including body weight gain (1-10 d, and 11-22 d) and feed conversion ratio (11-22 d, 1-36 d). An interaction (p < 0.05) between experimental factors was observed in terms of lower pH values in the crop (tendency, p = 0.053) and ceca. Both factors lowered the alpha diversity and Enterobacteriaceae and promoted Bacillaceae communities in the jejunum (p < 0.05). Interactions were also observed in terms of reducing Clostridiaceae in the ceca. In conclusion, the combined use of B. licheniformis and salinomycin in broilers' diets had beneficial effects.

Improvement of Cecal Commensal Microbiome Following the Insect Additive into Chicken Diet.

Gastrointestinal microbiota play an important role in regulating the metabolic processes of animals and humans. A properly balanced cecal microbiota modulates growth parameters and the risk of infections. The study examined the effect of the addition of 0.2% and 0.3% of Tenebrio molitor and Zophobas morio on cecal microbiome of broilers. The material was the cecum digesta. The obtained DNA was analyzed using 16S rRNA next generation sequencing. The results of the study show that the addition of a relatively small amount of Z. morio and T. molitor modulates the broiler cecum microbiome composition. The most positive effect on cecal microbiota was recorded in the 0.2% Z. morio diet. A significant increase in the relative amount of genus Lactobacillus, represented by the species Lactobacillus agilis and the amount of bacteria in the Clostridia class, was observed. Moreover, the addition of 0.2% ZM resulted in a significant increase of relative abundance of the family Bifidobacteriaceae with the highest relative abundance of genus Bifidobacterium pseudolongum. The obtained results indicate that the addition of a relatively small amount of insect meal in broiler diet stimulates colonization by probiotic and commensal bacteria, which may act as barriers against infection by pathogenic bacteria.

Nisin as a Novel Feed Additive: The Effects on Gut Microbial Modulation and Activity, Histological Parameters, and Growth Performance of Broiler Chickens.

Two independent experiments were performed to evaluate the effect of nisin alone or with monensin on gut microbiota, gut microbial activities, and histomorphology (exp 1) and the effect of nisin application in a dose‒response manner on the growth performance of broiler chickens (exp 2). A total of 900 one-day-old female Ross 308 chicks (400, exp 1; 500, exp 2) were randomly distributed to four groups (exp 1; 10 replicate pens per treatment with 10 birds each), i.e., NA, no additives; MON, monensin (100 ppm); NIS, nisin (2700 IU/kg diet); and MON + NIS, a mixture of monensin (100 ppm) and nisin (2700 IU/kg diet); or 5 treatments (exp 2), NA, no additives; NIS100, nisin (100 IU/kg diet); NIS200, nisin (200 IU/kg diet); NIS400, nisin (400 IU/kg diet); and NIS800, nisin (800 IU/kg diet). Nisin supplementation positively affected the microbiota of the gut by reducing potentially pathogenic bacterial populations in the jejunum and ceca. The bacterial fermentation in the jejunum was significantly lowered by nisin addition. The addition of nisin from 100 IU to 800 IU decreased the FCR value over the entire experimental period. According to the results, nisin can be considered a natural dietary supplement for broiler chickens.

Tenebrio molitor and Zophobas morio Full-Fat Meals in Broiler Chicken Diets: Effects on Nutrients Digestibility, Digestive Enzyme Activities, and Cecal Microbiome.

This study was conducted to investigate the effect of insect full-fat meals added in relatively small amounts to a complete diet on the coefficients of apparent ileal digestibility, short-chain fatty acid (SCFA) concentrations, bacterial enzymes, and the microbiota community in the cecal digesta of broiler chickens. In total, 600 one-day-old female Ross 308 broiler chicks were randomly assigned to six dietary treatments with 10 replicate pens/treatment and 10 birds/pen. The groups consisted of a negative control (NC) with no additives; a positive control (PC; salinomycin 60 ppm), and supplementation with 0.2% or 0.3% Tenebrio molitor or Zophobas morio full-fat meals. Z. morio (0.2%) addition increased the activities of α- and ß-glucosidase and α-galactosidase. Dietary insects significantly decreased the cecal counts of the Bacteroides-Prevotella cluster in comparison to those in the NC and PC. Whereas, Clostridium perfringens counts were increased in the broiler chickens subjected to the 0.3% Z. morio treatment. In conclusion, small amounts of full-fat insect meals added to broiler diets were capable of reducing the abundance of potentially pathogenic bacteria, such as the Bacteroides-Prevotella cluster and Clostridium perfringens. In addition, this supplementation was able to stimulate the GIT microbiome to produce enzymes, especially glycolytic enzymes.

Effects of insect diets on the gastrointestinal tract health and growth performance of Siberian sturgeon (Acipenser baerii Brandt, 1869).

BACKGROUND: Insects in the fish diet are a natural source of protein, fat, and other nutrients. These meals are considered an ecological replacement for fishmeal to improve growth parameters. The application of insect meals to fish diets has been studied, especially in continental fish. Data regarding the effects of insect meals on the gut health of Siberian sturgeon are not available. This study investigated the effects of full-fat Hermetia illucens (HI) and Tenebrio molitor (TM) meals on the gut health of juvenile Siberian sturgeon. Growth performance, gastrointestinal tract (GIT) histomorphology and the microbiome composition of juvenile Siberian sturgeon were analyzed. RESULTS: The inclusion of insect meals did not affect the growth performance or the survival rate. In the gastrointestinal tract histomorphology, a reduction in the mucosa thickness with the HI treatment was observed. In contrast, fish fed the TM diet had an increase in the thickness of the muscular layer. There were no observed significant differences in villus height among treatments. The analysis of the selected microbiota populations in the Siberian sturgeon gastrointestinal tract showed that insect addition affected the composition of the microbiome. The greatest effect on bacterial populations (Clostridium leptum subgroup, Enterobacteriaceae, Clostridium coccoides - Eubacterium rectale cluster, Aeromonas spp., Bacillus spp., Carnobacterium spp., Enterococcus spp. and Lactobacillus group) was observed with the HI diet (P < 0.05). The TM-based diet increased counts in the following bacterial groups: Clostridium coccoides - Eubacterium rectale cluster, Bacillus spp., Carnobacterium spp., and Enterococcus spp. In contrast, the TM diet decreased the total number of bacteria. The TM diet did not significantly affect the Clostridium leptum subgroup, Enterobacteriaceae, Aeromonas spp. or the Lactobacillus group. CONCLUSIONS: Fish meal replacement by the inclusion of 15% of full-fat Hermetia illucens and Tenebrio molitor (15%) meals did not affect the growth performance, survival rate or villus height of juvenile Siberian sturgeon. The present study suggests that an H. illucens-based diet positively affects the gut microbiota composition and intestinal morphology of juvenile Siberian sturgeon without negative changes in the villus height.

Insect Oil as An Alternative to Palm Oil and Poultry Fat in Broiler Chicken Nutrition.

This study was conducted to evaluate the effects of Tenebrio molitor (TM) oil as a total replacement for palm oil and poultry fat in broiler chicken diets on growth performance, nutrient digestibility, pancreatic enzyme activity, selected blood parameters and the lipid fatty acid compositions of liver and breast muscle tissues. A total of 72 seven-day-old female Ross 308 broiler chickens were used. The birds were randomly distributed into three groups with 12 replicates each, using two birds per replicate for 30 days in metabolic cages. The basal diet was supplemented with 5% palm oil, poultry fat or TM oil. There was no effect (p > 0.05) caused by the dietary oil replacement on the birds' performance and apparent nutrient digestibility. Liver size (p = 0.033), the concentration of hepatic triglycerides (p = 0.049) and total cholesterol (p = 0.048) were reduced by TM oil supplementation. Furthermore, TM oil supplementation increased n-3 and n-6 fatty acids (p = 0.006; p < 0.001, respectively) in breast muscle tissue. In conclusion, the use of TM oil in broiler chickens' diets did not show any adverse effects on performance, nutrient digestibility and blood biochemical parameters. Moreover, TM oil supplementation improved the fatty acid profiles of liver and breast muscle tissues.

Dietary Probiotics Affect Gastrointestinal Microbiota, Histological Structure and Shell Mineralization in Turtles.

Probiotics are widely used in nutrition, and their mode of action is intensively studied in mammals and birds; however, it is almost unknown in reptiles. In the present study, Trachemys scripta scripta and Sternotherus odoratus were used to assess the effects of dietary probiotics on chelonian gastrointestinal tract microecology. In the first, 20-week experiment, 40 young T. s. scripta were randomly distributed to four experimental groups: 1st, (CON)--with no additives; 2nd, (SSPA) with Bacillus subtilis PB6; 3rd, (MSP)--with multiple strain probiotic; and 4th, (SSPB) with Bacillus subtilis C-3102. The first study has shown that SSPA and MSP decreased the numbers of total bacteria, Enterobacteriace, Staphylococcus sp. and Streptococcus sp. excreted to water and increased the villous height and mucosa thickness in duodenum. SSPB improved the duodenal microstructure; however, it also increased numbers of kanamycin and vancomycin resistant bacteria, Staphylococcus sp. and Streptococcus sp., in water. In the second, 52-week experiment, 30 S. odoratus were randomly assigned to three dietary treatments. CON, SSPA and MSP groups. The MSP preparation increased the body weight gain, crude ash, Ca and P share in the turtles' shells. Both probiotics affected duodenal histomorphology. SSPA decreased the villous height, while MSP increased the villous height and mucosa thickness, and decreased the crypt depth. SSPA decreased the concentrations of bacteria excreted to water. In the case of intestinal microbiota, bacteria suppressing effects were observed in the case of both probiotics. MSP increased the number of Bifidobacterium sp. and Lactobacillus sp./Enteroccoccus sp., and decreased the number of Clostridium perfringens and Campylobacter sp. in the small intestine. In the large intestine it lowered, amongst others, Bacteroides-Pervotella cluster, Clostridium leptum subgroup and Clostridium perfringens numbers. The above-mentioned results suggest that probiotics are useful in turtle nutrition due to their positive effects on growth performance, shell mineralization, duodenal histomorphology and microbiota.

Dietary nisin modulates the gastrointestinal microbial ecology and enhances growth performance of the broiler chickens.

Due to antimicrobial properties, nisin is one of the most commonly used and investigated bacteriocins for food preservation. Surprisingly, nisin has had limited use in animal feed as well as there are only few reports on its influence on microbial ecology of the gastrointestinal tract (GIT). The present study therefore aimed at investigating effects of dietary nisin on broiler chicken GIT microbial ecology and performance in comparison to salinomycin, the widely used ionophore coccidiostat. In total, 720 one-day-old male Ross 308 chicks were randomly distributed to six experimental groups. The positive control (PC) diet was supplemented with salinomycin (60 mg/kg). The nisin (NI) diets were supplemented with increasing levels (100, 300, 900 and 2700 IU nisin/g, respectively) of the bacteriocin. The negative control (NC) diet contained no additives. At slaughter (35 days of age), activity of specific bacterial enzymes (α- and ß-glucosidases, α-galactosidases and ß-glucuronidase) in crop, ileum and caeca were significantly higher (P<0.05) in the NC group, and nisin supplementation decreased the enzyme activities to levels observed for the PC group. A similar inhibitory influence on bacterial activity was reflected in the levels of short-chain fatty acids (SCFA) and putrefactive SCFA (PSCFA) in digesta from crop and ileum; no effect was observed in caeca. Counts of Bacteroides and Enterobacteriacae in ileum digesta were significantly (P<0.001) decreased by nisin and salinomycin, but no effects were observed on the counts of Clostridium perfringens, Lactobacillus/Enterococcus and total bacteria. Like salinomycin, nisin supplementation improved broiler growth performance in a dose-dependent manner; compared to the NC group, the body weight gain of the NI900 and NI2700 groups was improved by 4.7 and 8.7%, respectively. Our findings suggest that dietary nisin exerts a mode of action similar to salinomycin and could be considered as a dietary supplement for broiler chickens.