Supplementary Feeding Research Articles

First documented observation of feeding behaviour of humpback whales (Megaptera novaeangliae) in its breeding range off the southern coast of Tanzania

Feeding and breeding activities of humpback whales (Megaptera novaeangliae) are generally understood to be geographically and temporally separated, with feeding activities taking places in the higher latitudes and breeding in lower latitudes. However, humpback whales may supplement their energy budgets by feeding outside of their polar foraging grounds, with opportunistic feeding behaviour being observed in mid-to-low latitudes globally. The records of supplementary feeding during migration in the southern hemisphere have been documented for various breeding stocks, with no records for the East African stock. We present the first to our knowledge record of the humpback whales feeding events in the coastal waters of Tanzania, that have been recorded on the dedicated boat surveys conducted during the humpback whales breeding seasons in 2023 and 2024 off Mnazi Bay in Mtwara region. Demonstrated behavioural plasticity may play an important role in adaptation strategies to global environmental changes and prey availability fluctuations, all of which affect recovering populations. Mnazi Bay seascape and its vicinity is an important habitat for at least 11 species of cetaceans documented, all of which depend on its productive waters for foraging, socializing and as a nursery for migrating humpback whales. This record underpins the importance of the protection of this habitat. However, future studies are needed to confirm and understand the details of the observed supplementary feeding behaviour of the humpback whales and the potential reasons behind its occurrence in Tanzania.

Asian seabass (Lates calcarifer) larval rearing using cyclopoid copepod (Apocyclops royi) live feed: A new approach

BackgroundThe Apocyclops species are gaining importance as suitable live feed for augmenting growth and survival of marine finfish larvae. In the present study, as a new approach Apocyclops royi is mass cultured using monoalgal diet (Chloroidium saccharophilum) and its nutritive value is assed and used as supplementary diet in the Asian seabass Lates calcarifer larval rearing.ResultsMass culture of A. royi with C. saccharophilum diet reached population density of 12,700 ± 454 ind./L on 21 days culture period. A. royi showed high ratio of DHA:EPA and EPA: ARA. Rearing experiments of the Asian seabass (Lates. calcarifer) 11 DPH larvae with copepod, Artimia nauplii and their combination diets recorded faster growth and maximum survival (90%) with A. royi + Artemia nauplii diet compared to A. royi and Artemia nauplii lone feeds. Seabass larval length and weight gain showed significant (p < 0.05) difference among the three dietary treatments. Significantly high content of essential fatty acids in the L. calcarifer larvae have been reported in A. royi + Artemia nauplii fed seabass larvae compared to individual A. royi and Artemia nauplii fed larvae.ConclusionsOur finding highlights the importance of incorporating A. royi as a supplementary feed for seabass larvae, which will bring improvement in their growth and survival leading to sustainable seed production of this fish.

Characterization of probiotic Bacillus sp. NP5 metabolites and its effect on female catfish broodstock rematuration

Probiotics are believed to contain active components that affect fish reproduction. This study aimed to evaluate the metabolite compounds contained in the probiotic Bacillus sp. NP5 and its effect on female catfish broodstock rematuration. The first step was to analyze the metabolite content of probiotic using liquid chromatography with tandem mass spectrometry LCMS/MS. Furthermore, feed supplementation was implemented with probiotic at concentrations of 106 CFU g-1 (P6), 108 CFU g-1 (P8), and control (C). Parameters observed included metabolite content of Bacillus sp. NP5, gonadosomatic index (GSI), hepatosomatic index (HSI), gonad histology, gonad maturity rate, fecundity, number of matured eggs, distribution of egg diameter, fertilization rate (FR), hatching rate (HR), larval survival (SR), rematuration period, and percentage of matured broodstock. The results showed that metabolites such as resveratrol (22.45%) and indoline (7.11%) are probably directly affecting reproduction. Other metabolites such as oxyresveratrol (22.95%) and vestitol (4.14%) are also thought to play an indirect role. Supplementation results showed the best reproductive performance in 108 CFU g-1 feed treatment with an increase in GSI (14.74%), HSI (1.65%), gonad maturity rate, percentage of mature eggs (86.00%), rematuration period (4 weeks), percentage of matured broodstock (100%), fecundity (243605.02 eggs/broodstock), FR (98.74%), HR (80.62%), and SR (87.31%). Application of probiotic Bacillus sp. NP5 can accelerate rematuration and improve reproductive performance of female catfish broodstock. Probiotics contain metabolites that have a positive effect on reproduction and can be an alternative in improving reproductive performance in female catfish broodstock. Keywords: Bacillus sp. NP5, female catfish, metabolites, probiotics, rematuration

Effect of Melatonin Treatment on Reproductive Hormones and Sexual Behaviors in Sheep

In seasonal oestrus animals such as sheep, out-off-season lambing practices and synchronization of oestrus are important in terms of herd management and farm economics. The present study aimed to determine the effects of melatonin implants administered before the breeding season on melatonin, estrogen, progesterone hormone concentrations, and sexual behavior in Tahirova sheep. The study was conducted on 60 Tahirova dairy ewes, aged 1-4 years, and 6 head rams, aged 1-2 years. On June 26, melatonin implants were administered to half of the ewes (18 mg dose/ewe) and rams (54 mg dose/ram). Fifteen days after the implantation of melatonin, all the ewes (530 g/ewe) and rams (660 g/ram) were given supplemental feeding (flushing) with grain feed for a period of 60 days. On August 1, the ewes exhibiting signs of estrus following the introduction of a ram were relocated to individual paddocks, where mating was conducted using the hand-mating method. The frequency of sniffing, touching the ram's scrotum, turning the ram, head-turning, and tail wagging was recorded during the hand-mating procedure. Additionally, the sexual behaviors exhibited by the ram were documented. Furthermore, an investigation was conducted to ascertain whether an interaction occurred within the first minute. The intervals, sexual interaction rate of the ewe, total frequency of sexual interaction, time per sexual interaction, and total sexual interaction time were observed. Blood samples were collected regularly on the initial day, the 21st day, the 42nd day, the 63rd day, the 94th day, and the 129th day for subsequent hormone analysis. Hormonal analyses were conducted using the ELISA method on blood serum samples. The melatonin hormone concentration was observed to be higher in the treatment (MT) group than in the control (C) group on the 63rd day (P=0.0476). The sexual interaction rate of the MT group was found to increase significantly in comparison to the C group (P=0.0045). Additionally, the gestation rate was shorter in the MT group than in the C group (P≤0.05). It can thus be concluded that the melatonin implant, when applied before the breeding season, significantly increases melatonin hormone concentrations on the 63rd day and significantly shortens the periods of gestation in Tahirova dairy sheep.

Effectiveness of NSP enzyme and organic chromium supplementation in low-protein feed on carbohydrate utilization in Pomfret Colossoma macropomum

This study aims to evaluate the effectiveness of NSP enzyme and organic chromium supplementation in low-protein Colosoma macropomum diet to increase carbohydrate utilization. The diets contains isoprotein (20%) and isoenergy. Factorial design with two factors, namely NSP enzyme (0 and 1 g/kg) and organic chromium (0, 1, and 2 mg/kg). Fish are reared in an aquarium measuring 80 x 50 x 35 cm3 and containing 75 L of water and stock at the density of 15 fish and reared for 60 days. The test parameters used are postprandial blood glucose levels, antioxidant activity, glycogen in muscle and liver, and growth performance. The results showed that the highest postprandial blood glucose levels were when the NSP enzyme was administered. Furthermore, the lowest malondialdehyde (MDA) values and the highest superoxide dismutase (SOD) and glutathione peroxide (GPx) values were obtained in fish fed feed containing 1 g/kg of NSP enzyme and 1 mg/kg organic chromium. Fish fed feed containing 1 g/kg NSP enzyme and 1 mg/kg organic chromium showed significant values in liver and muscle glycogen as well as growth performance compared to other treatments. From this research, it can be concluded that supplementation of NSP enzyme and organic chromium at doses of 1 g and 1 mg per kg of feed produces the best growth performance and anti-oxidant capacity in pomfret fish. Keywords: antioxidant, glycogen, growth performance, postprandial blood glucose ABSTRAK Penelitian ini bertujuan untuk mengevaluasi efektivitas suplementasi enzim NSP dan kromium organik pada pakan ikan bawal Colosoma macropomum rendah protein untuk meningkatkan pemanfaatan karbohidrat. Pakan yang digunakan mengandung iso protein (20%) dan isoenergi. Rancangan faktorial dengan dua faktor yakni enzim NSP (0 dan 1 g/kg) dan kromium organik (0, 1, dan 2 mg/kg). Ikan bawal dipelihara dalam akuarium dengan ukuran 80 x 50 x 35 cm3 dan berisi air 75 L diisi 15 ekor ikan dan dipelihara selama 60 hari. Adapun parameter uji yang digunakan adalah pengukuran kadar glukosa darah postprandial, aktivitas antioksidan, glikogen, dan kinerja pertumbuhan. Hasil penelitian menunjukkan kadar glukosa darah postprandial tertinggi pada pemberian enzim NSP. Selanjutnya nilai malondialdehyde (MDA) terendah dan superoxide dismutase (SOD) dan glutathione peroxide (GPx) tertinggi didapat pada ikan yang diberi pakan mengandung pada 1 g/kg enzim NSP dan 1 mg/kg kromium organik. Ikan yang diberi pakan yang mengandung 1 g/kg enzim NSP dan 1 mg/kg kromium organik menunjukkan nilai signifikan pada glikogen hati dan otot serta kinerja pertumbuhan dibanding perlakuan lainnya. Dari penelitian ini dapat disimpulakan bahwa suplementasi enzyme NSP dan Kromium organik pada dosis 1 g dan 1 mg per kg pakan menghasilkan kinerja pertumbuhan dan kapasitas antioksidan terbaik pada ikan bawal. Kata kunci: antioksidan, glikogen, glukosa darah postprandial dan kinerja pertumbuhan

Effects of Feed Supplementation With Fulvic Acid on the Systemic and Mucosal Protective Mechanisms of Juvenile Rainbow Trout (Oncorhynchus mykiss).

Rainbow trout (Oncorhynchus mykiss) is an important fish species raised in aquaculture, but it is susceptible to stress, infections diseases. The present study aimed to determine the effects of fulvic acid feed addition on the systemic and mucosal protective mechanisms of juvenile rainbow trout and to elucidate the underlying molecular mechanisms of changes in the gut. Rainbow trout (4.30 ± 0.6 g) diet was supplemented with different levels of fulvic acid: 0% (Control), 0.5%, 1% and 2%. At the end of 8-week feeding trial, growth parameters such as final weight gained weight (%), SGR (F1%) increased, and FCR (all levels) decreased significantly compared to the control group. We found that the activity of lysozyme, glutathione peroxidase, and catalase in the serum were significantly improved, especially after the addition of 0.5% and 1% of fulvic acid. At the same time, the immunoglobulin concentration in the skin mucus was increased with 0.5% supplementation. However, the expression of tnf-α, il-6 and gpx in the intestine was strongly upregulated after supplementation with 2%, indicating oxidative stress and inflammation with this level of fulvic acid inclusion. Furthermore, the mucus lysozyme activity was reduced at this concentration, which can increase the susceptibility to pathogen invasion. The results suggest that adding 0.5%-1% of fulvic acid to the feed of juvenile rainbow trout can help to improve their immune and antioxidative defenses and thereby support the wellbeing of fish.

Assessment of a new protocol strategy to control the ectoparasitic infestation in Nile tilapia (Oreochromis niloticus) using efficient natural products

This study aimed to evaluate alternative in vivo treatment trials using natural products for ectoparasitic infestation on Nile tilapia; these two products were not previously used in the treatment of parasitic fish diseases. So, a total of 400 Oreochromis niloticus (O. niloticus) fish measured 10–15 cm in length; 350 from a fish farm in (Kafr Elsheikh and 50 from Nile River (Al Bahr Al Aazam), Egypt. The examined fishes were 10–15 ± 0.5 cm long and weighed from 45 g ± 5. The collected fish were examined for different clinical abnormalities. Each part of the fish underwent a careful microscopic examination of mucous surrounding the skin; gills and fins. Two feed supplements were used experimentally to decrease mortality and treat fish against ectoparasites (Herb-All PARA-X® and Herb-All CALM®). Total mRNA was extracted from the gills of different examined groups. Glucose; nitric oxide; cortisol as well as lysozyme activity were assessed in all groups. The gills of the examined fish were collected for histopathological examination. Only, Dactyolgyrus sp. was recovered. The intensity of the parasite was counted per microscopic field. The treated groups showed low levels of the parameters compared to the control positive group. Up-regulation of both Tumor necrosis factor-α (TNF- α) and heat shock protein 70 (hsp-70) were detected in fins, gills, and skin in the infested tilapia. The treatment and prophylaxis significantly downregulated both genes in the studied organ in a dose-dependent manner. Recorded lesions which were scored according to their severity. In conclusion; following the use of those products, fish health has been greatly improved and that is indicated by findings of immune reactions as well as histopathology.

Preparation of ofloxacin molecularly imprinted polymer Raman sensor based on magnetic graphene oxide.

Ofloxacin is a commonly used quinolone antibiotic that is also used as a feed supplement in livestock production and in plant disease prevention and treatment. However, the excessive use and abuse of ofloxacin will accumulate along the food chain and endanger human health. Therefore, the development of a simple, rapid, and sensitive detection method for the determination of ofloxacin is critical. Herein, a detection method combining molecularly imprinted magnetic solid-phase extraction (MISPE) and surface-enhanced Raman spectroscopy (SERS) was developed for the detection of ofloxacin. Graphene oxide supported by magnetic beads was synthesized by a one-pot method, producing what was subsequently referred to as magnetic graphene oxide (MGO), and a molecularly imprinted membrane was synthesized on its surface by exploiting the ability of dopamine to self-polymerize under alkaline conditions. MGO@MIPs were obtained as the adsorbent for magnetic solid-phase extraction, which was used for the extraction and enrichment of ofloxacin in complex sample matrix, and then quantitative analysis was conducted by SERS. The developed method exhibited an excellent linear relationship with respect to ofloxacin concentration (10-5 to 102μgmL-1), with a detection limit of 9.7 × 10-6μgmL-1 in ultrapure water. Blank honey, milk, and pork samples spiked with ofloxacin at concentrations of 0.005, 0.1, 1, and 10μgmL-1 were extracted and determined using the developed method, with recoveries ranging from 93.1% to 105.6%. The results support the strong application prospects for the method, demonstrating simple and time-efficient operation and high accuracy.

Journal Review: Effectiveness of Supplementary Feed Ingredients on Egg Productivity and Body Weight Gain of Balibangtan Superior Hens

Feed is a major determining factor in the success of layer and broiler farming. The nutritional content of the feed must meet the requirements to increase livestock productivity. To improve chicken performance, we use additional feed. This review aims to determine the effectiveness of feed ingredients as a feed supplementation for chickens by using production waste, forage, household waste, forage, and enzymes to increase the growth and production of KUB chickens. Ingredients that can be used as feed additives include coconut pulp, pumpkin waste flour, papaya leaf waste, teak leaf extract, moringa leaves, tilapia plants, betel leaf juice, BS4, selenium chitosan, phytase, xylooligosaccharide, kesum leaf flour, sago pulp, spinach waste, and BSF maggot. The results of this review showed that the most effective feed ingredient was the supplementation of teak leaf extract (Tectona grandis), with a protein content of 4.9%, being the most effective feed ingredient in increasing egg productivity up to 15%. The supplementation of kesum leaf flour, with an average body weight gain of 426.97 g/head, is the most effective feed ingredient for increasing body weight growth in KUB chickens.

Growth performance, carcass traits, meat composition, digestibility coefficients and caecal microbiota of growing rabbits fed diets supplemented with a herbal mixture.

The study investigates the effect of dietary herbal mixture (HM) levels on growing New Zealand White (NZW) rabbits' performance, carcass characteristics, blood biochemicals, and microbiological characteristics from 5 to 13 weeks of age. In this study, 96 New Zealand White rabbits (male and female ratio 1:1) were used, and they were five weeks old. The rabbits were at random allocated into four experimental groups (n = 24 each) comprising 12 replicates, each with two rabbits. The 1st group acted as the control and received feed without additional supplements. The 2nd group received 0.30% HM, the 3rd group received 0.50% HM, and the 4th group received 0.70% HM. As the concentration of the herbal mixture extract was raised, the inhibitory zones grew significantly. The addition of HM to rabbit diets at a 0.5% concentration significantly increased body weight and weight gain compared to the control diet and other treatments. The apparent digestibility coefficient of ether extracts and the rabbits' capacity to absorb lipids significantly increased with increasing HM levels up to 0.7%. In addition, the HM increased high-density lipoprotein (HDL) and decreased triglycerides and low-density lipoprotein (LDL) in the blood. Interestingly, when rabbits were fed varying amounts of HM, all types of bacteria significantly declined, yet helpful lactic acid bacteria increased. In conclusion, HM supplementation improved rabbit growth, blood parameters, and gut microbial balance, with a 0.5% level yielding the best results, indicating that HM has significant potential as a novel feed supplement for growing rabbits.

The assessment of chemical composition and biological activity of faba bean pods as a potential feed additive utilized in piglets nutrition

The study addresses the utilization of food waste by-products from faba bean (Vicia faba L.) pods (FBP) as an alternative feed supplement to promote sustainable piglet growth by reducing antimicrobial use. Objectives include evaluation of FBP in terms of nutritional components (proximate composition, fibres, minerals), phytochemical composition (total phenols, HPLC-MS profiling), and in vitro biological activities. Air-dried FBP from the cultivar ‘Bizon’ contained high levels of crude protein (144 g/kg), dietary fibre (413 g/kg), potassium (27.8 g/kg), and iron (126 mg/kg). Phytochemical analysis of methanolic extract from FBP revealed significant levels of polyphenols, including vestitol, piscidic acid, hydroxyeucomic acid, quercetin, and kaempferol glycosides with no detectable tannins. The extract showed negligible activity against porcine digestive enzymes (α-amylase, lipase, and trypsin) (IC50 > 4 mg/mL) and demonstrated a dose-dependent antibacterial activity against Escherichia coli and Salmonella enterica in concentrations of 1–8 mg/mL. The extract had low cytotoxicity (IC50 = 432.6 µg/mL) against IPEC-J2 – cells derived from porcine jejunal epithelium. The results indicate that FBP ‘Bizon’ is a valuable source of bioactive compounds with antibacterial properties, without adverse effects on porcine enzymes or IPEC-J2 cells, supporting its potential as a sustainable feed in piglet nutrition, in line with circular economy concepts.

Goat agribusiness extension in Komala Village, South Wangi-Wangi District

The Komala Village community has many goats but there are many problems faced by the community such as dead fetuses, malnutrition, limited health care, environmental conditions, lack of knowledge and training and limited infrastructure. Therefore, the aim of this extension activity is to provide education to the farming community about the correct way to raise goats. This activity was carried out on Friday, March 26, 2023 at 16.00 WITA - Finish, located at the Gazebo of the Komala Village Head's House, South Wangi-Wangi District, Wakatobi. Counseling materials presented to the community: (1) Types of appropriate and balanced feed for goats, (2) Natural feed, supplementary feed, and fermented feed, (3) How to organize feeding according to age, weight, and maintenance objectives, (4) Efficient feeding methods, and (5) Mixing and serving feed techniques. After following the goat farming extension, the community response was as follows: (1) enthusiasm and participation, (2) increased understanding, (3) interest in new practices, (4) awareness of the importance of improving goat rearing practices (5) satisfaction with information, (6) positive perception of benefits, (7) desire for further training, and (8) better collaboration. The conclusion from this community service activity is that the community in Komala Village still has low knowledge regarding how to raise goats. Although they have experience in raising goats, many things can still be improved in farming practices to achieve better results. As for what needs to be improved in community knowledge, such as feed management, care, production management, use of technology, and business management skills.

Microencapsulated-Bioactive Compounds from Medicinal Leaf Extracts Used as Feed Supplements: Effects on In Vitro Rumen Fermentation, Microbial Population and Methane Mitigation

Microencapsulated-Bioactive Compounds from Medicinal Leaf Extracts Used as Feed Supplements: Effects on In Vitro Rumen Fermentation, Microbial Population and Methane Mitigation

Carrion in Bomas: Multiple Observations of Cheetah (Acinonyx jubatus) Scavenging Events and Potential Causes in Managed Populations.

Facultative scavenging can be observed across a large range of carnivorous mammals but is an uncommon behavioural trait in cheetahs (Acinonyx jubatus). Very few incidents of cheetahs scavenging have been reported, with no explanation given as to why it may occur. In this paper, we provide three more observations of cheetahs scavenging between 2019 and 2023 in three different protected areas in South Africa and Malawi. We suggest a common factor between these observations, namely that all adult individuals involved were temporarily housed in holding enclosures (bomas) during relocation processes and were provisioned with carrion as supplemental feed. The observed scavenging events could also have been influenced by the easy access to food in a situation where food acquisition was potentially difficult (i.e. old age, loss of hunting partner, mother with cubs). We hypothesise that these contributing factors, combined with the prior exposure of the adult individuals to eating carrion, could be a potential explanation for our observations of cheetahs scavenging. These observations provide a basis for further research into cheetah scavenging behaviour and the potential impacts of translocations that require prolonged holding periods on wildlife behaviour post-release. Understanding these behavioural shifts is crucial for cheetah conservation, as successful reintroduction efforts depend on the ability of cheetahs to adapt to new environments and food acquisition strategies.

Effect of common carp group, mass yield and supplemental feeding on basic water quality parameters under semi-intensive pond management in Central Europe: Implications for selective breeding under near-natural conditions

Effect of common carp group, mass yield and supplemental feeding on basic water quality parameters under semi-intensive pond management in Central Europe: Implications for selective breeding under near-natural conditions

Morphological change in an isolated population of red squirrels (Sciurus vulgaris) in Britain.

The mechanical properties of dietary items are known to influence skull morphology, either through evolution or by phenotypic plasticity. Here, we investigated the impact of supplementary feeding of peanuts on the morphology of red squirrels (Sciurus vulgaris) from five populations in Britain (North Scotland, Borders, Jersey and two temporally distinct populations from Formby (Merseyside)). Stable isotope analysis confirmed dietary ecology in 58 specimens. Geometric morphometrics were used to analyse three-dimensional and two-dimensional shape variation across 113 crania and 388 mandibles, respectively. Nitrogen isotope ratios (δ15N) were lower in the 1990s and 2010s Formby squirrels (suggesting a diet with an increased proportion of peanuts), and higher in other populations. Significant differences in cranio-mandibular shape were found between all populations, with 1990s Formby red squirrels exhibiting a morphology associated with reduced masticatory efficiency. This effect was partially reversed following a reduction in supplementary feeding of peanuts. We propose that these morphological changes are related to the reduced mechanical effort needed to process peanuts relative to naturally occurring food items. This could be an example of diet-induced plastic changes to the skeleton in non-muroid wild mammals, although further research is needed to exclude other driving factors such as genetics.

Tetrastigma hemsleyanum as a feed additive: modulating gut microbiota for enhancing nutritional transport and growth performance in Jinhua yellow chickens.

Tetrastigma hemsleyanum (TH) has attracted much attention for its heat clearing and detoxification effects, but whether it can become an effective feed supplement in chickens remains unclear. Herein, a total of 120 male Jinhua yellow chickens (two-mth-old) were randomly divided into into four groups (CON, TH-L, TH-M, and TH-H) for a 56-day feeding trial to explore its effects on growth performance and underlying mechanism. Results revealed that dietary TH notably increased the average daily growth (ADG), and decreased the average daily feed intake (ADFI) and feed conversion ratio (FCR) in TH-H group during 29-56 days. Meanwhile, dietary TH improved the development of duodenum and notably increased the contents of essential amino acids and flavor amino acids, while the serum oxidation stress index as well as abdominal fat deposition were not affected in Jinhua yellow chickens. Additionally, TH supplementation notably increased gut microbiota richness, then selectively increased the colonization of potential probiotics and the microbial abundance associated to amino acid synthesis and metabolic pathways in duodenum. Furthermore, qPCR analysis results preliminarily verified that dietary TH not only enhanced intestinal amino acids (rBAT and EAAT3) and peptides (PepT1 and APN) transport but also alleviated the inflammation (IL-1β, IL-6 and IFN-γ), thus thereby improved intestinal development and growth performance in Jinhua yellow chickens. These findings demonstrated that TH is a feed additive that can improve growth performance, muscle amino acids composition and intestinal development.

Does Dietary Supplementation With Quercetin or Rutin Impact Growth, Stress, and Immunity in Pikeperch (Sander lucioperca) and the Water Microbial Community in Recirculating Aquaculture?

Pikeperch Sander lucioperca is a species mainly reared in recirculating aquaculture systems (RASs), but it remains very sensitive to stress and handling. Plant phenolic compounds such as quercetin or rutin are frequently investigated as feed additives to improve the growth and well‐being of fish reared in RAS, but their impact on pikeperch and RAS microbial communities has never been studied. Our objectives were to (i) test the effect of quercetin or rutin addition to feed (2.2 g kg−1 diet) on the growth, stress, and innate immunity of pikeperch reared in RAS and (ii) assess the consequence of those additives on the RAS water microbial communities. Pikeperch of 307 (±45) g starting weight were reared in nine experimental RAS (n = 3) and fed for 84 days on a diet enriched or not (control treatment) with quercetin or rutin (feeding rate: 1.5%). Considering the start (T0) and the end (T84) of the experiment, we compare the fish growth, feed conversion ratio (FCR), morphoanatomical and physiological status, and the water microbial diversity and composition through a metabarcoding approach performed on the 16S rRNA gene. Whereas no effect on fish was recorded with quercetin (624.0 ± 21.9 g final weight), rutin (558.0 ± 10.7 g final weight) reduced pikeperch growth (0.54 vs. 0.69%–0.64% day−1), and increased FCR (1.70 vs. 1.2–1.4) compared to control (622.0 ± 16.8 g final weight) and quercetin treatments, respectively. No effect was observed on all fish physiological parameters analyzed separately, but a multifactorial analysis reveals that fish fed with rutin have a different overall physiological state. Quercetin induced a shift in the microbial community structure and composition, whereas there was no effect of treatments on microbial richness or evenness. A dietary supplementation with quercetin or rutin has no or a negative impact on pikeperch growth and physiology and modifies the microbial diversity in RAS. Effects of additives being species‐dependent, precautions must be taken when formulating feed supplements, which must be based on precise studies.

Black garlic (Allium sativum) powder, a promising feed supplementation improves hematological and immunological indices, body composition, and growth performance of golden pompano (Trachinotus blochii)

Black garlic (Allium sativum) powder, a promising feed supplementation improves hematological and immunological indices, body composition, and growth performance of golden pompano (Trachinotus blochii)

Effect of Vit E, potassium, and alcohol-fermented feed supplementation before transport on body weight, carcass characteristics, and meat color of Hanwoo Steers

Effect of Vit E, potassium, and alcohol-fermented feed supplementation before transport on body weight, carcass characteristics, and meat color of Hanwoo Steers