Formulation of Fish Feed with Optimum Protein-bound Lysine for African Catfish (Clarias Gariepinus) Fingerlings

Effects of dietary lysine, methionine, and tryptophan on regulating GH-IGF system and modulation of inflammatory and immune response in Pangasius bocourti

The present study assessed the effects of methionine, lysine, and tryptophan on the growth performance, amino acid composition, and immune-related gene expression of basa catfish (Pangasius bocourti). Fish (n = 260; initial weight = 10.00 ± 1.00 g) were fed eight isonitrogenous (30%) diets, each containing different combinations of tryptophan (Trp), methionine (Met), and lysine (Lys) (A0: no amino acids, A1: Trp, A2: Lys, A3: Met, A4: Trp + Met, A5: Lys + Trp, A6: Met + Lys, A7: Lys + Trp + Met, 6 g/kg each) for 10 weeks. The experiment consisted of eight treatments, each with three replicates (n = 15/replicate). After the 10-week feeding trial, the fish were intraperitoneally injected with 0.2 mL of Streptococcus iniae for a 14-day bacterial challenge. Following the feeding trial and bacterial challenge, growth parameters, insulin-like growth factor-I, haematological profile, blood biochemistry, interleukin-6, and interleukin-10 revealed that amino acid supplementation significantly improved both growth and immune response in all treatments except A0. Significant differences were observed in crude protein and amino acid profiles across treatments. Interleukin-10 levels were significantly elevated in all treatments except in the positive control (+ve A0). Compared to the positive control, interleukin-6 levels were significantly reduced (P < 0.05) in all treatments. Superoxide dismutase and catalase activity increased in response to the bacterial challenge, while malondialdehyde levels gradually decreased. The A7 diet (Lys + Trp + Met: 6 g/kg) yielded the most favourable results, enhancing the immune response, which may further support the commercial production of Pangasius bocourti.

Natural Feed Supplements From Crustacean Processing Side Streams for Improved Growth of Finfishes and Crustaceans: A Review

Natural feed additives of plant/animal/microbial origin are researched as supplements in aquaculture to improve the properties of feed, minimize the usage of chemical alternatives, reduce food safety risks and ensure sustainability to combat global food and nutritional security. Side streams generated during shellfish processing possess valuable ingredients: protein, lipids, carotenoids, minerals and chitins. Considering the current trend of organic farming and antibiotic-free fish and shellfish, crustacean processing side streams and their derivatives seem promising and emerging resources as natural additives/supplements for formulating high-quality feeds with superior benefits. Lower concentrations of chitin and chitosan in diets are reported to stimulate the growth of shellfish and finfish under controlled conditions. Oligomers of chitosan and nano-chitosan are also the other potential derivatives as natural supplements in feed for better growth performance of aquaculture varieties. This review focuses on the significance of crustacean processing side streams and their derivatives, especially shrimp head meal, chitin, chitosan and chitosan oligosaccharides as potential natural additives in aquafeeds for promoting the growth performance of cultured fin fishes and shell fishes. Utilization in aquafeeds and the development of natural value-added supplements from crustacean processing side streams, especially shrimp head and shell leftover, offer an answer to the negative environmental impact due to its dumping; reduce the dependency on food fish for fish meal production & fishmeal for aquafeeds; solution to maintain the economic viability of the fish farmers & industry as well as to ensure the supply of safer and healthy aquatic foods to meet the objectives of sustainable development goals.

Design and application of artificial rare L-lysine codons in Corynebacterium glutamicum

Background: L-lysine is widely used in the feed, food, and pharmaceutical industries, and screening for high L-lysine-producing strains has become a key goal for the industry. Methods: We constructed the rare L-lysine codon AAA by corresponding tRNA promoter replacement in C. glutamicum. Additionally, a screening marker related to the intracellular L-lysine content was constructed by converting all L-lysine codons of enhanced green fluorescent protein (EGFP) into the artificial rare codon AAA. The artificial EGFP was then ligated into pEC-XK99E and transformed into competent Corynebacterium glutamicum 23604 cells with the rare L-lysine codon. After atmospheric and room-temperature plasma mutation and induction culture, 55 mutants (0.01% of total cells) with stronger fluorescence were sorted using flow cytometry, and further screened by fermentation in a 96-deep-well plate and 500 mL shaker. Results: The fermentation results showed that the L-lysine production was increased by up to 9.7% in the mutant strains with higher fluorescence intensities, and that the highest screening positive rate was 69%, compared with that in the wild-type strain. Conclusion: The application of artificially constructed rare codons in this study represents an efficient, accurate, and simple method for screening other amino acid-producing microorganisms.

The experience of using a mineral chelate additive for growing juveniles of the African sharptooth catfish (Clarias Gariepinus) in a recirculating aquaculture system

Growing fish in a recirculating aquaculture system (RAS) involves various stress factors that directly affect their physiological condition. This study aimed to investigate the effect of a chelated organic-mineral additive including Fe, Mn, Cu, Zn, Co, Se and I; on the rearing performance of juvenilecatfish (Clariasgariepinus) under RAS conditions. Four groups of fish (n=50) were formed: a control group (receiving standard feed) and three experimental groups (receiving standard feed with biogenic elements chelate compounds in different concentrations). At the end of the experiment (30 days), the physiological condition of the fish was evaluated by the growth rate, internal organs condition, blood serum biochemical indices and histological examination of the middle intestine. The survival rate of fish in the experimental groups was 96-98%. According to the results, the absolute increase was 14,30% in group III, 11,13% in group II and 6,71% in group I, compared to the control. However, the use of chelated compounds in high concentrations can cause necrosis and erosion of the apical part of the villi (groups II and III). Blood biochemical analysis of fish (group II and III) receiving medium and high concentrations of chelated compounds showed high ALT activity, which was 23,02% (p<0,05) and 45,19% (p<0,05) higher compared to control, respectively. Mineral-chelate compounds, of the studied composition, at a concentration of 0,5 g/kg positively affect the histological structure of the midgut of Clarias gariepinus. This dosage of the investigated feed additive can be recommended for the practical application of rearing Clariasgariepinus in closed water installations.

Valorization of vinasse and whey to protein and biogas through an environmental fungi-based biorefinery

Vinasse and whey are wastewaters that are produced in large quantities in the sugar-to-ethanol and dairy industries, respectively. They pose a considerable threat to the environment due to the high concentration of nutrients and COD. In this study, the potential of producing protein-rich fungal biomass and biomethane from vinasse and whey through a two-stage biorefinery was examined. In the first stage, an edible and safe for human filamentous fungus, Neurospora intermedia, was cultivated on these wastewaters. To maximize the fungal biomass yield, the cultivation parameters, i.e., pH, vinasse to whey ratio, incubation time, and nutrients supplementation, were optimized. The highest yield of 12.0 g biomass per L of wastewaters was obtained by cultivation at pH 6.5 and vinasse to whey ratio of 25:75 (v/v) for 96 h with nitrogen source supplementation. The N. intermedia biomass contained about 45% protein and noticeable essential amino acid contents, comparable to commercial sources of protein for aquatic feed such as soybean meal and fishmeal. In the second stage, the effluent of fungal cultivation was anaerobically digested to produce 425 mL/g VS biomethane. Overall, 1 m³ of wastewater yielded 5.4 kg crude protein and 10.3 m³ methane, accompanied by 93.3% COD removal.

Combined and Singular Effects of Ethanolic Extract of Persian Shallot (Allium hirtifolium Boiss) and Synbiotic Biomin®IMBO on Growth Performance, Serum- and Mucus-Immune Parameters and Antioxidant Defense in Zebrafish (Danio rerio)

Simple Summary

The present study investigated the effect of combined and singular ethanolic extract of Persian shallot and synbiotic Bomin^®IMBO in zebrafish. The aim of this study is to measure a range of parameters consisting of growth performance, serum and mucus immune parameters, and antioxidant defense. The results indicated that the measured parameters have a positive effect and hence we can suggest administration of these additives in zebrafish culture.

Abstract

This study was carried out to evaluate combined and singular effects of ethanolic extract of Persian shallot (Allium hirtifolium Boiss) and synbiotic Biomin^®IMBO on growth performance, innate immune responses, and antioxidant defense in zebrafish (Danio rerio). Fish with initial weight of 151.90 ± 0.31 mg were allocated in 21 10-L glass aquariums. The experimental groups were as follows: T1, control (without any supplementation); T2, 1% synbiotic; T3, 3% synbiotic; T4, 1% Persian shallot (as a medical plant); T5, 3% Persian shallot; T6, 1% Persian shallot and 1% synbiotic; T7, 3% Persian shallot and 3% synbiotic. At the end of the experiment (60 days), all treatments significantly showed higher final weight (FW), weight gain (WG), WG (%), and specific growth rate (SGR) compared with the fish fed on control diet. Furthermore, both synbiotic Biomin^®IMBO and Persian shallot significantly improved intestine immune parameters including lysozyme, alternative complement hemolytic activity (ACH50), total immunoglobulin (total Ig), and myeloperoxidase (MPO) of zebrafish compared to fish fed on control diet (p < 0.05). Also, in all experimental groups, hepatic catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) activities significantly increased compared to the control group. Whereas, the highest MDA level was observed in the control group compared to the treatments (p < 0.05). Moreover, skin mucus immune parameters of zebrafish have been noticeably improved with synbiotic Biomin^®IMBO and Persian shallot compared to fish fed on the control diet (p < 0.05). The results indicate that synbiotic or Persian shallot supplemented diet could enhance the general health status of the zebrafish.

Integrated process for protein, pigments, and biogas production from baker's yeast wastewater using filamentous fungi

Baker's yeast production industry generates large quantities of high chemical oxygen demand (COD) wastewater. The integration of baker's yeast wastewater (BYW) for an innovative two-step waste biorefinery process by producing protein-rich fungal biomass and biogas along with COD and nutrients removal was the main object of the present research. In the first step, fungal biomass production from BYW was investigated using four species of filamentous fungi. The maximum biomass yield of 5.13 g/L BYW containing 43.8% mycoprotein and 36.3% COD removal was achieved by A. oryzae. In the second step, to produce biogas and further remove organic matter, the effluent of fungal fermentation was subjected to anaerobic digestion and COD removal between 22.4 and 44.2% was obtained. Overall, 1 m³ of BYW yielded 5.13 kg of protein-rich biomass and 1.42 m³ of methane. Additionally, pigment production using N. intermedia was investigated, and 1.54 mg carotenoids/g biomass was produced.

Changes in digestive enzyme activities during the early ontogeny of the South American cichlid (Cichlasoma dimerus)

Cichlasoma dimerus is a neotropical cichlid that has been used as a biological model for neuroendocrinology studies. However, its culture is problematic in terms of larval feeding to allow having enough fry quantity and quality. Larviculture requires full knowledge about the digestive system and nutrition; therefore, this study was intended to assess the digestive enzymes' changes at different ages during the early ontogeny. Acid protease activity was detectable from the first day after hatching (dah), increasing to its maximum peaks on 9 dah. In contrast, alkaline proteases had low activity in the first days of life but reached their maximum activity on 17 dah. Chymotrypsin, L-aminopeptidase, and carboxypeptidase A activities increased at 6 dah, while trypsin activity was first detected on 13 dah and reached its maximum activity on 17 dah. Lipase and α-amylase activity were detectable at low levels in the first days of life, but the activity fluctuated and reaching its maximum activity at 21 dah. Alkaline phosphatase continued to oscillate and had two maximum activity peaks, the first at 6 dah and the second at 19 dah. Zymograms of alkaline proteases on day 6 dah six revealed four activity bands with molecular weights from 16.1 to 77.7 kDa. On 13 dah, two more activity bands of 24.4 and 121.9 kDa were detected, having a total of six proteases. The enzymatic activity analyzes indicate the digestive system shows the low activity of some enzymes in the first days after hatching, registering significant increases on 6 dah and the maximum peaks of activities around at 17 dah. Therefore, we recommend replacing live food with dry feed and only providing dry feed after day 17 dah.

Spent Mushroom Substrate Based Fish Feed Affects The Growth of Catfish (Clarias gariepinus)

A preliminary study was conducted to identify the effect of Spent Mushroom Substrate (SMS), a biomass from mushroom cultivation, towards catfish growth and intake performance when developed into fish feed. The fish experiment on catfish was conducted up to 12 weeks and analyzed on the weight, length size, survival rate and digestibility for the three types of SMS based feed in pellet form and a commercial pellet that applied for ten catfish each. Among the SMS based fish feed, Ganoderma obtained the highest weight of 32.46 g followed by White (30.71 g) and Abalone (17.74 g). For the length size, Ganoderma, White and Abalone SMS based feed had achieved in average 18.05 cm, 17.12 cm and 14.85 cm respectively. Commercial feed still manage to obtain the highest weight and length size as 39.33 g and 20.83 cm respectively. The survival rate was found 30 % higher in SMS based feed compared to commercial feed. The digestibility study of dry matter for Ganoderma, White and Abalone SMS based feed were found 77.34 %, 78.20 %, 77.76 % respectively whereas for commercial pellet was 60.92 % indicates that SMS based feed was consumed and digested better than commercial feed.

Evaluation of Filamentous Fungal Biomass Cultivated on Vinasse as an Alternative Nutrient Source of Fish Feed: Protein, Lipid, and Mineral Composition

The rapid growth of aquaculture and scarcity of conventional fish feed supplements has prompted the introduction of new sustainable supplementation sources. In this study, the potential of five strains of fungal biomass of Ascomycetes and Zygomycetes edible filamentous fungi, Aspergillus oryzae, Neurospora intermedia, Rizhopus oryzae, Monascus purpureus, and Fusarium venenatum, cultivated on vinasse, a by-product of the bioethanol industry, as alternative protein sources for fishmeal in the fish diet was evaluated. It was observed that 5% vinasse with an initial pH of 5–6.5 can support fungal biomass yields of 34.3 ± 2.4–118.5 ± 3.9 g DM/L for A. Oryzae, N. intermedia, and R. oryzae. High protein contents of about 44.7%, 57.6%, and 50.9% (w/w), and fat contents of 7.0%, 3.5%, and 5.5% (w/w) were obtained for A. oryzae, N. intermedia, and R. oryzae, respectively. The latter three fungi species contained noticeable amino acid contents, including promising profiles of amino acids that are highly compatible with those of fishmeal. These findings provide evidence that fungal biomasses, with their relatively high protein content, good amino acid profiles, and other essential nutrients, are a promising supplementation alternative that can be produced from low-value by-products and organic-rich waste streams like vinasse to meet the dietary protein requirements in fish feed.

Dynamics of a vertical-flow windrow vermicomposting system

Large-scale vermicomposting under outdoor conditions may differ from small-scale procedures in the laboratory. The present study evaluated changes in selected properties of a large-scale vertical-flow windrow vermicomposting system with continuous feeding with household biowaste. The windrow profile was divided into five layers of differing thickness and age after more than 12 months of vermicomposting. The top layer (0-30 cm, age <3 months) was characterised by partially decomposed organic matter with a high pH value and an elevated carbon/nitrogen (C/N) ratio. The earthworm biomass was 15 g kg^-1 with a population density of 125 earthworms per kilogram predominantly found in clusters. The greatest amount of fungi (3.5 µg g^-1 dw) and bacteria (62 µg g^-1 dw) (expressed as phospholipid fatty acid analysis) was found in this layer. Thus, the top layer could be used for an additional cycle of windrow vermicomposting and for the preparation of aqueous extracts to protect plants against diseases. The lower layers (graduated by 30 cm and by 3 months of age) were mature as reflected by the low content of ammonia nitrogen, ratio of ammonia to nitrate nitrogen and dissolved organic carbon, and high ion-exchange capacity and its ratio to carbon. These layers were characterised by elevated values for electrical conductivity, total content of nutrients, available magnesium content, and a relatively large bacterial/fungal ratio. On the basis of the observed properties, the bottom layers were predetermined as effective fertilisers.