Feed Utilization Research Articles

Dose response effects of dietary clove and peppermint oils on the growth performance, physio-metabolic response, feed utilization, immunity, and organ histology in African catfish (clarias gariepinus).

Phytochemicals and essential oils have been widely used as growth promoters in aquaculture. However, the optimal dose of a blend of essential oils for promoting the growth and health of African catfish (Clarias gariepinus) remains largely unknown. Therefore, the present study aimed to assess the dose-response effects of dietary supplementation with a blend of clove and peppermint oils (CPO) on growth indices, feed utilization, physio-metabolic responses, immunity, and organ histology in African catfish. Catfish (105.1 ± 0.5g) were fed diets containing 0.0 (control; CPO0), 1.0 (CPO1), 2.0 (CPO2), or 3.0 mL CPO/kg diet for two months. The results displayed that fish performance and feed intake significantly improved with increasing CPO levels in a linear manner (P < 0.01). Additionally, the specific growth rate and hemoglobin (R2 = 84.6%) levels showed quadratic improvements with the optimal doses at 1.12 mL and 1.6 mL/kg diet, respectively. The inclusion of dietary CPO linearly affected aspartate aminotransferase (AST; R2 = 93.1%), alanine aminotransferase (ALT; R2 = 97.7%), alkaline phosphatase (ALP; R2 = 97.0%), and glucose (R2 = 85.9%) levels in the plasma of catfish (P < 0.001). Increasing the concentrations of dietary CPO led to a quadratic decrease in creatinine (R2 = 98.7%), uric acid (R2 = 94.8%), and cortisol (R2 = 87.1%; P < 0.001), with optimal doses confirmed at 1.75, 2.7, and 1.3-mL CPO per kg of diet, respectively. Dietary CPO has a significant modulatory impact on immune-antioxidant variables in African catfish in a dose-dependent manner. Increasing CPO in the fish diets resulted in a quadratic increase in the levels of immunoglobulin G (IgG; R2 = 98.8%), lysozyme activity (R2 = 93.9%), and total antioxidant capacity (R2 = 84.9%). The corresponding dose-response curves displayed that the optimal doses were at 1.85, 2.1, and 1.8 mL/kg of diet. Furthermore, superoxide dismutase (SOD), and reduced glutathione (GSH) levels were significantly improved in all CPO-treated groups in a quadratic manner, with optimal doses at 1.25 mL (R2 = 90.6%) and 1.55 mL (R2 = 89.7%) per kg of diet. Catfish fed diets supplemented with CPO showed gradual improvements in hepatocytes (HP), and blood vessels (BV) with an increased number of binucleated cells. Moreover, catfish fed diets containing CPO had improvement in the tubular epithelium, Bowman's capsule, and a few melanomacrophage areas. This study revealed that CPO supplementation at an optimal dose of 1-2 mL/kg of diet significantly improved growth performance, feed utilization, metabolic processes, and immune and antioxidant functions in African catfish.

Probiotic properties of Bacillus licheniformis HN318 and comparison of the effects of its bacterial cells and cultures on growth, immunity and disease resistance of hybrid grouper (Epinephelus polyphekadion♂ × Epinephelus fuscoguttatus♀)

IntroductionBacillus species are probiotics commonly utilized in aquaculture to enhance aquatic animal growth, inhibit pathogens, and strengthen immunity. However, research comparing the effects of probiotic bacterial cells and cultures is limited. This study aimed to evaluate the probiotic potential of Bacillus licheniformis strain HN318 and compare its impact on growth, immunity, and disease resistance in hybrid grouper when administered as bacterial cells or cultures.MethodsThe study involved assessing the auto-aggregation capability, gastrointestinal stress resistance, and safety of HN318. Enzymatic activities and antibacterial properties of HN318 cultures and bacterial cells were also compared. Hybrid grouper were fed with HN318 cultures and bacterial cells for 8 weeks, and their growth, feed utilization, immune responses, and survival rates upon challenge with Vibrio harveyi were evaluated. Additionally, the expression of immune-related genes was analyzed.ResultsHN318 exhibited high auto-aggregation and gastrointestinal stress resistance, and was found to be safe for use in aquaculture. Cultures of HN318 displayed higher protease, amylase, and antibacterial activities compared to bacterial cells. Both forms significantly improved growth and feed utilization in hybrid grouper. Notably, HN318 cultures induced higher levels of immune enzymes and activities, and provided better protection against V. harveyi challenge, with a higher relative percent survival compared to bacterial cells. Furthermore, HN318 cultures upregulated the expression of immune-related genes more than bacterial cells.DiscussionThis study highlights the potential of both HN318 cultures and bacterial cells as immune enhancers for hybrid grouper. However, HN318 cultures demonstrated superior probiotic properties, including higher enzymatic activities, antibacterial properties, and immunomodulatory effects. These findings provide new insights and references for the diverse application forms of probiotics in aquaculture, suggesting that cultures may be more effective than bacterial cells in enhancing the health and performance of aquatic animals.

Corrigendum to “Effects of dietary carbohydrate levels on growth performance, feed utilization, liver histology and intestinal microflora of juvenile tiger puffer, Takifugu rubripes” [Aquacult. Rep. 36 (2024) 102035

Corrigendum to “Effects of dietary carbohydrate levels on growth performance, feed utilization, liver histology and intestinal microflora of juvenile tiger puffer, Takifugu rubripes” [Aquacult. Rep. 36 (2024) 102035

EGCG improve meat quality, restore lipid metabolism disorder and regulate intestinal flora in high-fat fed broilers.

Excessive oil addition can easily result in decreased disease resistance in broilers, a drop in meat quality, and disorders of glucose and lipid metabolism. Epigallocatechin gallate (EGCG) is an important bioactive component of tea and has been shown to have promising effects on the metabolism of nutrients. This study was aimed at investigating the impact of EGCG supplementation through a high-fat diet (HFD) on production performance, meat quality, lipid metabolism and the influence of intestinal flora in broiler chickens. During the experimental phase, the broilers were segregated into three groups and provided with distinct diets: a basal diet, a high-fat diet, and a high-fat diet supplemented with EGCG, respectively. The results showed that EGCG increased lightness (L*) 24 h (P < 0.05), and decreased drip loss (P < 0.05) of chicken meat; Enhanced the presence of non-essential and flavor amino acids in muscle tissue and greatly enhanced the antioxidant capacity of broilers, leading to a noteworthy upregulation of antioxidant genes at the genetic level (P < 0.05); Reduced in blood lipids, blood glucose, liver and abdominal fat accumulation in high-fat diet-induced obese chickens (P < 0.05), markedly improved serum and liver biochemical parameters, and histological analysis results also demonstrated that EGCG markedly decreased hepatic lipid accumulation caused by HFD feeding. Compared to high-fat diet-induced obese chickens, supplementation of EGCG significantly lowered hepatic fatty acid synthase (FAS) expression and lipid synthesis metabolites, while fatty acid decomposition enzymes showed no significant changes. Furthermore, EGCG significantly decreased inflammation levels and oxidative damage in high-fat diet-induced obese chickens (P < 0.05). 16S rRNA gene sequencing revealed that dietary supplementation of EGCG reduced the abundance of Bacteroidota and Dielma, while increasing the abundance of Firmicutes, Turiciactor, Romboutsia, and Parasutterella, thereby modulating the microbial composition. Dietary EGCG may have induced some of the alterations due to increased activity of the enzymes catalase (CAT) and superoxide dismutase (SOD), as well as decreased oxidation of proteins and lipids. Collectively, EGCG shows potential as an effective dietary additive for improving the high fat feeding of broiler health, feed nutrient utilization, and meat quality and nutritional value. This experiment provides a powerful new idea for the efficient utilization of oil feed and has important theoretical significance.

Effects of chronic cold stress and thermal stress on growth performance, hepatic apoptosis, oxidative stress, immune response and gut microbiota of juvenile hybrid sturgeon (Acipenser baerii ♀ × A. schrenkii ♂)

The current study was conducted to investigate the effects of chronic cold stress and thermal stress on the growth performance, hepatic oxidative status, immune response, apoptosis and gut microbiota in juvenile hybrid sturgeon. The fish (initial mean weight: 21.4 ± 0.3 g) was reared at three temperatures (14 °C, 22 °C, and 30 °C) for 16 d, which were termed as low temperature group (LT), moderate temperature group (MT), and high temperature group (HT), respectively, and the second group was regarded as control group in this study. Each group was assigned randomly to three tanks with 15 fish per replica. The results indicated that cold stress resulted in a significant reduction of growth metrics and a significant increase of feed conversion ratio in fish compared with MT group. Interestingly, cold stress increased hepatocyte apoptosis revealed by TUNEL staining, along with nuclear disappearance in H&E-stained sections and elevated serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Transcriptional levels of apoptosis-related genes and toll-like receptor signaling pathway components were significantly up-regulated in liver under cold stress. Compared with control group, in terms of thermal stress, the growth performance and feed utilization of fish were declined to some extent compared with MT group. Moreover, high temperature significantly elevated hepatic productions of malondialdehyde and hydrogen peroxide, as well as increased activities of some antioxidant enzymes in liver. In addition, low and high temperature induce changes in the composition of gut microbiota. Overall, the results suggested that cold stress decelerated growth performance, induced hepatocyte apoptosis, and enhanced innate immunity in hybrid sturgeon to cope with additional stressors. Whereas, thermal stress resulted in hepatic oxidative stress in liver and the protective responses in the antioxidant enzymes in fish were activated. These results provided insights into the different physiological adaptation strategies in responsive to cold stress and thermal stress in this cold-water fish.

Gut microbiome and functional prediction of metabolic pathways associated with fat an muscle tissue accumulation in beef cattle

Reducing economic losses, improving feed utilization, maintaining health and improving the quality of finished products in the livestock industry are the main tasks that need to be solved. Scientists around the world are already proposing to use animals based on their genetic selection, which characterizes high-quality phenotypic traits. Methods are used to measure the external data and meat qualities of cattle using advanced systems for recognizing live animal bodies, including depth cameras and soft reconstruction of three-dimensional shape. However, one of the criteria for assessing animals can be the analysis of the genetic bank of microorganisms, closely related to the functional activity of the animal's digestive system. A comprehensive assessment of gene expression, taxonomic structure of the microbiome, exterior characteristics and meat productivity in combination will provide more accurate forecasts for the use and selection of animals. Our study presents the results of metagenomic sequencing (NGS) of the intestinal contents of young animals (n=40) raised in a feedlot, and annotates the association of the microbiome with their live weight and marbling degree, predicting the metabolic pathways with which these genes were associated. The analysis (LEfSe) revealed a taxonomic difference in the intestinal contents of animals with high and low live weight, the genera Clostridium sensu stricto, Clostridium XlVa, Treponema were predominant in animals with lower live weight.

Prediction of dry matter intake in growing Black Bengal goats using artificial neural networks.

Dry matter intake (DMI) determination is essential for effective management of meat goats, especially in optimizing feed utilization and production efficiency. Unfortunately, farmers often face challenges in accurately predicting DMI which leads to wastage of feed and an increase in the cost of production. This investigation aimedto predict DMI in Black Bengal goats by using body weight (BW), body condition score (BCS), average daily gain (ADG), and metabolic body weight (MBW) by applying an artificial neural network (ANN) model. A total of 144 observations were collected from 18 goats over a 4-month period for each input (BW, ADG, MBW and BCS) and output (DMI) variable. These input variables were taken fortnightly and correlated with DMI. The presence of a significant positive correlation between DMI with BW (r = 0.968, p < 0.01), BCS (r = 0.687, p < 0.01), ADG (r = 0.608, p < 0.01), and MBW (r = 0.971, p < 0.01) indicated potential for ANN model development. ANN model with 10 hidden layer neurons trained using GDX and LOGSIG transfer function emergeds as the high-performing model for predicting DMI in Black Bengal goats, achieving the highest R2 (0.9693) and the lowest MSE (0.0013) among the configurations considered. Comparison between the three models revealed that the DMI was estimated more accurately by the ANN model than by linear and second-order non-linear models. ANN may therefore be used to predict DMI with high accuracy and reliability in place of otherregression methods.

Effect of Solid-Fermented Brewer’s Spent Grain on Growth, Metabolism, and Oxidative Status of European Seabass (Dicentrarchus labrax)

Replacing traditional agricultural ingredients with biotechnologically improved agro-industry by-products in fish diets promotes sustainable aquaculture, reduces production costs and carbon footprint, and promotes a circular economy. Brewer’s spent grain (BSG) is one such by-product. Solid-state fermentation (SSF) of BSG with Aspergillus ibericus enhances its nutritional value and digestibility for European seabass. The present study further evaluates the potential of dietary inclusion of BSG-SSF on growth performance, feed utilization, plasma metabolite profile, intermediary metabolism, and oxidative status of European seabass juveniles compared to the unfermented product. A practical diet (45% protein; 18% lipids) was tested against diets incorporating 10% or 20% of BSG or BSG-SSF, replacing plant-protein feedstuffs. Triplicate groups of European seabass juveniles (49 g initial weight) were fed for 10 weeks. Unfermented BSG (10% and 20%) reduced growth and feed efficiency. In comparison, the 20% BSG-SSF diet promoted growth and feed efficiency similar to the control group, while the 10% BSG-SSF diet surpassed the control diet. Whole-body protein content was unaffected, but lipid and energy content decreased with increasing BSG levels, regardless of fermentation. Plasma glucose and phospholipid levels and hepatic activities of glucokinase and malic enzymes decreased with increasing BSG, irrespective of fermentation. BSG-SSF incorporation increased plasma triglyceride levels and decreased hepatic transaminase activities but did not affect hepatic key enzyme activity of β-oxidation or lipogenesis. It also reduced antioxidant enzyme activity and lipid peroxidation. In conclusion, BSG negatively impacted growth performance, while BSG-SSF supported inclusion levels up to 20% without performance loss. Further, the 10% BSG -SSF diet outperformed the control diet.

Therapeutic Effect of Dietary Turmeric (Curcuma longa) on Growth Performance, Hematology Profile and Immunity Parameters of Common Carp (Cyprinus carpio)

Medicinal plants are rich in diverse nutrients and antioxidants that promote growth and have immunostimulating activities for fish. In aquaculture phytomedicines have gained importance worldwide because they are easily available, non-toxic to aquatic life. Turmeric (Curcuma longa) is among the most suitable natural ingredient due to its biological effects. Therefore, a study has been conducted to determine the effect of turmeric on the growth performance, hematology and immunity of common carp Cyprinus carpio. For this purpose, 180 fingerlings of common carp with average initial weight (30.23±0.04 g) were divided into six groups containing five treatment groups. Each tank was stocked with 10 fingerlings. Treatments were maintained in triplicates. Fish were fed with basal diet supplemented with graded level of turmeric at different concentrations i.e. TE0 (control), TE1 (1.0%), TE2 (2.0%), TE3 (3.0%), TE4 (4.0%) and TE5 (5.0%). Fish were fed twice a day at 3% body weight for 12 weeks. Results showed that fish growth was higher in all treatments as compared to the control group. The feed efficiency ratio (FER), feed conversion ratio (FCR), specific growth rate (SGR) and condition factor (K), of fish fed with turmeric enriched diet were found to be better than the control group. TE4 diet exposed to 4% Turmeric, showed maximum growth in terms of growth performance and feed utilization. Moreover, haematology profile and immunity parameters also improved by turmeric supplementation. The result of the present study shows that turmeric has the potential to enhance the growth performance of common carp. Overall, the TE4 % dietary group showed better growth performance and immunity than the control group and other treated groups.

Nutritional Performance of Extracted Soybean, Full-Fat Soya and Maize Gluten Meal Compared to a Fishmeal-Based Reference Diet for Juvenile Tilapia (Oreochromis Mossambicus)

Modern diets for aquaculture are highly complex and utilize a broad range of ingredients, including animal and plant byproducts. This study focused on the rationale of obtaining primary nutritional responses of tilapia evaluating two major ingredients, namely soybean meal and maize gluten meals by replacing fishmeal at set levels of incorporation. A two-onth investigation evaluated selected plant protein sources compared to fish meal protein in scientifically formulated diets for fingerling tilapia (Oreochromis mossambicus). Six nutritionally balanced diets: one reference (control) diet (fish-meal based diet), three selected plant proteins (solvent extracted soybean, full-fat soybean, and maize gluten) were substituted for the LT (Low Temperature dried) fish-meal-based control diet protein at 50% respectively, and the remaining diets were replaced with 75% inclusion of solvent extracted soybean and maize gluten meals. Results showed that solvent extracted soybean meal, 50 (SESB50), Full fat soybean, 50% (FFSB50) and Maize gluten, 50% (MG50) fed tilapia did not appreciably differ in their growth performance (percent weight gain of 279.36, 249.23, and 194.13% respectively) with a final mean weight of 14.95g being significantly superior (&lt;0.05) for the fishmeal control (CO) group. Substitution of fish meal with solvent-extracted soybean and maize gluten at levels of 75% gave the poorest growth performance and Feed Efficiency (FE) (7.01g final weight, 51% FE). However, the MG50 diet also showed inferior feed utilisation performance. However, tilapia fed on a full-fat soybean diet (FFSB50) did not vary significantly from the control (CON) diet in terms of protein utilisation (ANPU) at 34.20% and 37.53% respectively. Whilst this preliminary study concluded that limitations on the use of the selected plant proteins in diets for tilapia are apparent, several approaches that could result in the future improvement of the nutritional value of soybean and maize gluten products for use in fish diets are also stated.

Yeast cell wall polysaccharides accelerate yet in-feed antibiotic delays intestinal development and maturation via modulating gut microbiome in chickens

BackgroundIt is important to promote intestinal development and maturation of chicks for feed digestion and utilization, intestinal health, and disease resistance. This study aimed to investigate the effects of dietary yeast cell wall polysaccharides (YCWP) addition on intestinal development and maturation of chickens and its potential action mechanism.Methods180 one-day-old male Arbor Acres broilers were randomly assigned to three groups containing control (basal diets without any antibiotics or anticoccidial drug), bacitracin methylene disalicylate (BMD)-treated group (50 mg/kg) and YCWP-supplemented group (100 mg/kg).ResultsCompared with control group, in-feed antibiotic BMD continuous administration significantly decreased crypt depth (d 21) and villus height (d 42) along with mucosal maltase activity (d 42) in the ileum (P < 0.05). Also, BMD markedly downregulated gene expression levels of β-catenin, lysozyme, occludin and FABP-2 (d 21) and innate immune related genes CD83 and MHC-I mRNA levels (d 42, P < 0.05), and decreased goblet cell counts in the ileum of chickens (d 21 and d 42, P < 0.05). While, TLR-2, TLR-6 and iNOS mRNA abundances were notably upregulated by BMD treatment (d 42, P < 0.05). Nevertheless, dietary YCWP addition significantly increased the ratio of villus height to crypt depth (d 21), villus surface area (d 21 and d 42), ileal alkaline phosphatase and maltase activities as well as goblet cell (d 21 and d 42) and IgA-producing plasma cell numbers as compared to BMD treatment (d 21, P < 0.05). YCWP addition also upregulated gene expression levels of Lgr5, Wnt/β-catenin signaling pathway related gene (Wnt3, β-catenin, d 21; β-catenin, d 42), intestinal cells proliferation marker Ki-67 and barrier function related genes (occludin, d 21 and d 42, P < 0.05). Moreover, YCWP significantly increased antigen presenting cell marker related genes (MHC-II, d 21; CD83 and MHC-I, d 42), TLR-1, TLR-2 and TLR-6 mRNA levels (d 21, P < 0.05). Cecal microbiome analysis showed that YCWP addition obviously improved cecal microbial composition, as indicated by increasing relative abundance of Fournierella, Psychrobacter and Ruminiclostridium on d 21, and Alistipes and Lactobacillus on d 42, which were positively related with gut development and maturation related indexes (P < 0.05).ConclusionCollectively, YCWP promoted yet antibiotic BMD delayed intestinal morphological and immunological development linked with modulating gut microbiome in chickens.

Dietary Tannic Acid Promotes Growth Performance and Resistance Against Aeromonas hydrophila Infection by Improving the Antioxidative Capacity and Intestinal Health in the Chinese Soft-Shelled Turtle (Pelodiscus sinensis).

To investigate the effect of tannic acid (TA) on the growth, disease resistance, and intestinal health of Chinese soft-shelled turtles, individual turtles were fed with 0 g/kg (CG), 0.5 g/kg, 1 g/kg, 2 g/kg, and 4 g/kg TA diets for 98 days. Afterwards, the turtles' disease resistance was tested using Aeromonas hydrophila. The results showed that 0.5-4 g/kg of dietary TA increased the growth performance and feed utilization (p < 0.05), with 2.38 g/kg being the optimal level for the specific growth rate (SGR). The addition of 0.5-4 g/kg of TA in diets increased the mucosal fold height and submucosa thickness of the small intestine, which reached a maximum of 2 g/kg. The addition of 0.5-2 g/kg of TA effectively reduced the cumulative mortality that had been induced by A. hydrophila, with the 2 g/kg dosage leading to the lowest mortality. Additionally, 1-4 g/kg of TA improved the T-SOD, CAT, and GSH-Px activities during infection, while 2 g/kg of dietary TA enhanced the richness and diversity of the microbiota, for example, by increasing Actinobacteria but inhibiting Firmicutes. The transcriptome demonstrated that the predominant differentially expressed genes (DEGs) in TA2 were mainly enriched in the PPAR signaling pathway (Acsl5, Apoa2, Apoa5, Fabp1, Fabp2, and Fabp6); in glycine, serine, and threonine metabolism (Chdh, Gatm, and Shmt1); and in steroid biosynthesis (Cel, Hsd17b7, Soat2, and Sqle). The main differentially expressed metabolites (DEMs) that were discovered by means of metabolome analysis included cholylhistidine, calcipotriol, 13-O-tetradecanoylphorbol 12-acetate, and hexahomomethionine in CG vs. TA2. Integrative analyses of two omics revealed that 2 g/kg of TA mitigated inflammation by activating the PPAR signaling pathway and regulating the lipid metabolism via multiple pathways, such as steroid biosynthesis and α-linolenic acid metabolism. In general, the inclusion of 2 g/kg of TA in turtle diets can optimally promote growth and bacterial resistance by maintaining intestinal health and improving antioxidant capacity.

Garlic Powder Evaluation as Feed Additive on Nile Tilapia (Oreochromis niloticus L.) Growth Performance, Feed Utilization, Gill Parasitic Treatment, and Monogenean Diversity

Garlic Powder Evaluation as Feed Additive on Nile Tilapia (Oreochromis niloticus L.) Growth Performance, Feed Utilization, Gill Parasitic Treatment, and Monogenean Diversity

Dietary rosemary oil with/without zymogen forte improves water quality, growth hormones, immune-physiological response, stress resilience, and health status of Chelon ramada grown in groundwater

With freshwater resources becoming scarce worldwide, mariculture is a promising avenue to sustain aquaculture development, especially by incorporating brackish and saline groundwater (GW) use into fish farming. A 75-day rearing trial was conducted to evaluate fish growth, immune response, overall health, and water quality of Chelon ramada cultured in brackish GW and fed on a basal diet (BD) augmented with rosemary oil (RO) or RO + zymogen forte™ (ZF) as an anti-flatulent. Five treatments were administrated in triplicate: T1: fish-fed BD without additives (control group); T2: fish-fed BD + 0.5 g RO /kg diet; T3: fish-fed BD + 0.5 g RO and 1 g ZF /kg diet; T4: fish-fed BD + 1 g RO /kg diet; T5: fish-fed BD + 1 g RO and 1 g ZF /kg diet. Three hundred fish (8.51 ± 0.01 g/fish) were housed in 15 fiberglass tanks (1500-L tank). The results revealed significant improvements (P < 0.05) in growth performance, survival, growth hormone, and insulin-like growth factor-1. Additionally, there were decreases in the feed conversion ratio (FCR) and the levels of nitrogen by-products (NH4, NH3, and NO2) and pathogenic bacterial counts in the rearing water when fish were fed diets supplemented with RO and RO + ZF. Furthermore, significant reductions in the levels of plasma stress indicators (cortisol, creatinine, and glucose) were detected. In addition, there were significant enhancements observed in the levels of innate immune markers, such as white blood cells, total protein, albumin, and immunoglobulin. The complement system, specifically complement 3 and complement 4, also showed considerable improvements. Furthermore, there were increases in plasma heat shock proteins HSP70 and HSP90, as well as enhanced antioxidant activity. These gains were associated with healthier liver and intestines. The investigation demonstrated that adding 0.5–1 g RO / kg diet or RO + ZF to a C. ramada diet has many benefits, including reducing the levels of nitrogen by-product chemicals and pathogenic bacterial load in GW used in growth tanks. Furthermore, significant improvements were observed in the rates of growth and associated hormones, efficiency of feed utilization, blood indicators, immune function, condition of internal organs (namely the intestine and liver), and overall health of the fish.

The Effect of Dietary Sodium Alginate on the Growth and Survival of Giant Freshwater Prawn (Macrobrachium rosenbergii)

The giant freshwater prawn, Macrobrachium rosenbergii, is a valuable aquaculture species known for its rapid growth, adaptability to environmental variations, and high nutritional value. However, challenges such as high mortality rates, algal blooms, dissolved oxygen depletion, and pathogen outbreaks constrain its cultivation. The overuse of antibiotics in aquaculture raises significant environmental and health concerns, including antimicrobial resistance. This study explores the potential of sodium alginate, a natural polysaccharide derived from brown algae, as a prebiotic and immunostimulant for improving growth and feed efficiency in M. rosenbergii. Juvenile prawns (~0.2 g) were cultured for 60 days and fed experimental diets supplemented with sodium alginate at concentrations of 0 g/kg (control, T0), 1.0 g/kg (T1), 2.0 g/kg (T2), and 3.0 g/kg (T3). Growth performance, feed utilization, and survival rates were assessed bi-weekly. Results showed significant improvements (p&lt;0.05) in growth parameters, including mean weight gain (MWG) and specific growth rate (SGR), in prawns fed a 2.0 g/kg sodium alginate diet (T2). At the end of the experiment, T2 recorded the highest mean weight, MWG, SGR, and lowest feed conversion ratio (FCR, 2.395 ± 0.068), demonstrating superior feed utilization efficiency. In contrast, prawns fed a 3.0 g/kg sodium alginate diet (T3) showed reduced growth performance and feed efficiency. This study highlights the efficacy of sodium alginate as a dietary supplement to enhance growth, feed efficiency, and sustainability in freshwater prawn aquaculture, with the optimal dosage identified as 2.0 g/kg. These findings support sodium alginate's potential as an eco-friendly alternative to antibiotics in aquaculture systems.

Impact of Feeding Frequency on Growth Performance and Antioxidant Capacity of Litopenaeus vannamei in Recirculating Aquaculture Systems.

Feeding frequency is crucial for the growth and development of white shrimp (Litopenaeus vannamei) at various life stages. Although higher feeding frequencies can enhance growth, manual feeding methods significantly increase labor costs. Automatic feeding systems offer a cost-effective and efficient alternative, yet their application in intensive shrimp culture remains under-researched. This study evaluates different feeding frequencies for L. vannamei in intensive aquaculture tanks, focusing on growth performance, survivability, feed utilization, digestive and antioxidant capacities, and economic viability. Juvenile shrimp (3.85 ± 0.3 g) were cultured for 63 days with feeding frequencies of 6, 8, 10, and 12 times/day (A6, A8, A10, and A12 groups, respectively) using automatic feeders, with a control group fed manually 6 times/day (M6). Results indicated that automatic feeding significantly improved final body weight, specific growth rate, and feed conversion ratio compared to manual feeding. Among automatic feeding groups, A6 and A8 showed optimal performance, with a quadratic regression identifying 7.83 times/day as the optimal frequency. While digestive enzyme activity remained consistent across groups, A6 and A8 demonstrated significantly higher antioxidant enzyme levels (superoxide dismutase (SOD) and glutathione peroxidase (GPx)) and lower lipid peroxidation (MDA), suggesting superior digestive and antioxidant capacities. Pearson's correlation confirmed a positive relationship between SOD and GPx. Economically, the A8 group achieved the highest profitability. Consequently, a feeding frequency of 6-8 times/day using automatic feeders is recommended as an optimal and feasible strategy for intensive white shrimp culture in this life stage.

Bacillus subtilis HGCC-1 improves growth performance and liver health via regulating gut microbiota in golden pompano

Probiotics as green inputs have been reported to regulate metabolism and immunity of fish. However, the mechanisms by which probiotics improve growth and health of fish are unclear. Therefore, the aim of this study was to investigate the effect of Bacillus subtilis HGCC-1, an indigenous probiotic isolated from fish, on growth performance, host lipid metabolism, liver inflammation and gut microbiota of golden pompano. 160,000 golden pompanos with the initial body weight of 93.6 ± 5.0 g was randomly assigned to two dietary groups: Control and HGCC-1 (control diet supplemented with 0.3 g/kg Bacillus subtilis HGCC-1 fermentation product), and after three weeks of feeding, 26 golden pompanos were randomly collected from each group for gut microbiome and host phenotype analysis. Dietary supplementation with Bacillus subtilis HGCC-1 significantly promoted growth performance (P < 0.05) and enhanced feed utilization. Besides, HGCC-1 improved liver health and alleviated hepatic steatosis and inflammation. Furthermore, Bacillus subtilis HGCC-1 enhanced intestinal lipid absorption, promoted hepatic utilization of dietary fat by improving hepatic lipid uptake/transport and fatty acid β-oxidation to provide energy, and reduced hepatic TG level (P < 0.05), which may be the potential mechanism of Bacillus subtilis HGCC-1-mediated growth promotion. Finally, Bacillus subtilis HGCC-1 significantly altered the structure and function of gut microbiota (P < 0.05), leading to enrichment of beneficial taxa such as Bacillus (P < 0.0001) and increased of the ratio of “Functional Group 2/Functional Group 1” (P = 0.00092). Interestingly, the ratio of “Functional Group 2/Functional Group 1” was linked to the growth traits (Spearman, P < 0.05), while the intestinal abundance of Bacillus was correlated with serum TG in fish (Spearman, R = 0.47, P = 0.00091), suggesting a role of the intestinal microbiota in HGCC-1 mediated effect on growth and lipid metabolism. In summary, Bacillus subtilis HGCC-1 promotes growth performance, alleviate hepatic steatosis and enhances liver health via regulating gut microbiota in golden pompano, which ultimately showed as beneficial effect of fish growth and health.

Influence of Lactobacillus plantarum and cellulase on fermentation quality and microbial community in mixed silage of Solanum rostratum and alfalfa

IntroductionIncreasing the research on the development and utilization of unconventional feed resources is one of the effective ways for the sustainable development of herbivorous animal husbandry. China is one of the countries most severely impacted by the invasion of the alien plant Solanum rostratum Dunal (S. rostratum), but this resource has not been used effectively.MethodsThe aim of this study was to investigate the effects of Lactobacillus plantarum and cellulase on the fermentation quality and microbial community in mixed silage of S. rostratum and alfalfa. Treatments were a control treatment with no additive (CK), Lactobacillus plantarum (LP), cellulase (CE), and Lactobacillus plantarum in combination with cellulase (L+C), all of which were stored at ambient temperature for 7, 15, 30, and 60 days.ResultsThe results showed that the mixture could retain dry matter (DM), crude protein (CP), and water soluble carbohydrates (WSC) content, increase lactic acid (LA) content, decrease pH and alkaloid content, and improve fermentation quality during silage. The use of additives increased the abundance of Lactobacillus and Weissella, which was related to the improvement of the quality of mixed silage and the degradation of total alkaloids. Differential microbial functions were mainly carbohydrate metabolism, biosynthesis of secondary metabolites and carbon metabolism.ConclusionThe application of additives and mixed silage provides a new idea for the feed utilization of S. rostratum.

Toxicity of standing milkvetch infected with Alternaria gansuense in white mice.

Standing milkvetch (Astragalus adsurgens) is widely distributed in the wild in Eurasia and North America and has been bred for cultivated forage in China. Yellow stunt and root rot disease caused by Alternaria gansuense is the primary disease of standing milkvetch. A. gansuense promotes the production of swainsonine in the plant. This study aimed to determine the safety of standing milkvetch that is infected with A. gansuense as forage for animals. Two-week-old specific pathogen-free (SPF) male white mice were fed a commercial mouse feed (CMF), healthy plant feed (HPF) and diseased plant feed (DPF) for 3 or 6 weeks. We observed histological changes in the liver and kidney tissues of the mice and measured their daily feed intake, daily water intake, body weight, feed utilization, organ coefficients, and activities of serum enzymes. The results showed that the daily feed intake of the mice that were fed DPF and HPF was significantly higher (p < 0.05) than those fed CMF at 3 and 6 weeks. The highest increase was observed in the daily water intake of the mice fed HPF (p < 0.05) followed by DPF and CMF. However, the mice fed DPF gained the least weight (p < 0.05). There was a significantly higher percentage of liver weight to body weight of the mice fed DPF (p < 0.05) than those fed HPF for 3 weeks and those fed CMF for 3 and 6 weeks. There were significantly higher levels of concentrations of alanine aminotransferase in the mice fed DPF and HPF than those fed CMF for 3 weeks (p < 0.05) and 6 weeks (p < 0.01). However, there was no significant difference in the mice fed HPF than those fed DPF. There were significantly higher of lactate dehydrogenase concentration (p < 0.001), while the blood urea nitrogen was lower in the mice fed DPF than those fed HPF and CMF at 3 weeks. There was a significantly higher percentage of numbers of lymphocytes in the blood of the mice fed DPF (p < 0.05) than those fed HPF, but the percentages of monocytes and eosinophils were significantly lower. Comparatively, there were more apparent pathological changes in the liver and kidney tissues of the mice fed with DPF than in those fed with HPF. These findings indicate that standing milkvetch was toxic to white mice, and infection with A. gansuense increased its toxicity. Therefore, we conclude that standing milkvetch plants infected by A. gansuense must never be used as animal feed under any circumstances. Additionally, the amount of healthy standing milkvetch fed to animals should be appropriate, avoiding long-term or excessive feeding.

Effects of Mixing Ratio and Lactic Acid Bacteria Preparation on the Quality of Whole-Plant Quinoa and Whole-Plant Corn or Stevia Powder Mixed Silage.

Quinoa is the only single plant that can meet all the nutritional needs of human, and its potential for feed utilization has been continuously explored, becoming a prosperous industry for poverty alleviation. In order to further tap the feeding value of whole quinoa, develop quinoa as a feed substitute for conventional crops such as corn, and improve its comprehensive utilization rate, this experiment analyzed the silage quality and mycotoxin content of mixed silage of whole-plant quinoa (WPQ) with whole-plant corn (WPC) or stevia powder(SP) in different proportions, and further improved the silage quality of mixed silage by using two lactic acid bacteria preparations (Sila-Max and Sila-Mix). The quality, microbial population, and mycotoxin levels of quinoa and corn silage, as well as that of the mixed silage of quinoa and stevia, were evaluated using single-factor analysis of variance. The impact of various lactic acid bacteria preparations on the quality of whole-quinoa and whole-corn mixed silage was investigated through two-factor analysis of variance. WPQ and WPC were mixed at the ratio of 5:5 (QB5), 6:4 (QB6), 7:3 (QB7), 8:2 (QB8), 9:1 (QB9) and 10:0 (QB10). SP was mixed with WPQ at the supplemental levels of 0.2% (QB10S2), 0.4% (QB10S4), 0.6% (QB10S6), 0.8% (QB10S8) and 1.0% (QB10S10). After 60 days of silage, the silage indexes, the number of harmful microorganisms, and the mycotoxin levels were measured, to explore the appropriate ratio of mixed silage. The membership function analysis showed that the quality of mixed silage of WPQ with SP was better, and the optimal addition amount of SP was 0.6%. The results of Max and Mix on the quality improvement test of WPQ with WPC mixed silage showed that the two lactic acid bacteria formulations increased CP and AA content, and reduced NH3-N/TN; pH was significantly lower than the control group (p < 0.01), and LA was significantly higher than the control group (p < 0.01). The microbial count results showed that the addition of lactic acid bacteria preparation significantly reduced the number of molds and aerobic bacteria, and the effect of Mix was better than that of Max. When the mixing ratio was between QB7 and QB10, mold was not detected in the lactic-acid-bacteria preparation groups. Max and Mix significantly reduced the levels of mycotoxins, both of which were far below the range of feed safety testing, and 16S rRNA sequencing revealed that the silage microbiota varied with different mixing ratios and whether lactic acid bacteria preparations were used. Max and Mix increased the relative abundance of Firmicutes, with Mix having a more significant effect, especially in the QB6 (65.05%) and QB7 (63.61%) groups. The relative abundance of Lactobacillus was significantly higher than that of the control group (p < 0.05). The relative abundance of Enterobacteriaceae and Streptococcus were negatively and positively correlated with the addition level of quinoa, respectively. Comprehensive analysis showed that adding 0.6% SP to the WPQ and using Mix in mixed silage of WPQ and WPC with the proportion of WPQ no less than 70% had the best silage effect, and was more beneficial to animal health.