Dietary Taurine Supplementation Research Articles

Enhanced cholesterol utilization and impact on growth through taurine supplementation in high plant-based diets of Pacific white shrimp, Penaeus vannamei in biofloc system

Cholesterol is vital for the optimal growth and physiological function of Pacific white shrimp, Penaeus vannamei. Due to limited availability of fish meal, plant-based ingredients are increasingly added in the shrimp diet which limit the availability and utilization of cholesterol. This study investigated the synergistic effects of dietary taurine and cholesterol supplementation on growth and physio-metabolic responses of Pacific white shrimp, Penaeus vannamei fed with high plant-based protein diets reared in a biofloc system for 60 days. A basal diet (control) comprised 82.55 % plant-based ingredients and 36 % crude protein. Five isonitrogenous and isolipidic diets were prepared (T1-T5) with cholesterol and taurine supplements at inclusion levels of 0.15 % and 0.16 % in T1 and T2, respectively. In the rest of the treatments, T3, T4, and T5, the combinations of cholesterol and taurine were 0.15 % and 0.16 %; 0.05 % and 0.24 %; 0.25 % and 0.08 %, respectively. The experimental diets were allocated to triplicate groups of 100 shrimp per tank following a completely randomized design. The results showed that shrimp fed T3 diet have a significantly (P < 0.05) higher percentage of weight gain, specific growth rate (SGR), percentage of survival, and protein efficiency ratio (PER) with efficient feed conversion ratio (FCR) (1.14±0.06) compared to other treatments. The hematological, antioxidant, and digestive enzyme activities, except amylase activity, were significantly (P < 0.05) higher in shrimp fed T1 and T3. Total bile acid content in T3 fed shrimp was higher than in other dietary treatments (P < 0.05). The results indicated that supplementing a combination of 0.15 % cholesterol and 0.16 % taurine in a high plant-based diet significantly improved growth performance, nutrient utilization, and physio-metabolic responses of P. vannamei.

Dietary Taurine Supplementation Influence on the Growth and Metabolic activity of Fish: Juvenile, Cichlid, and Teleost

Dietary Taurine Supplementation Influence on the Growth and Metabolic activity of Fish: Juvenile, Cichlid, and Teleost

Taurine amino acid supplementation impacts performance, blood hematology, oxidative stress, and jejunum morphology in broiler chickens.

Excess levels of free radicals cause oxidative damage to cells. Taurine is a rare amino acid with antioxidant effects whose dietary deficiency increases oxidative damage to the cell membrane. To investigate the effects of dietary taurine supplementation on performance, blood hematology, oxidative stress, and jejunum morphology in broilers, 300 broilers (Ras 308, 1D of age) were randomly allocated into 4 groups with 5 replicates of 15 birds. The experimental treatments included basic diet (control treatment) and basic diet with 1, 3, and 6g/kg taurine amino acid. During 1 to 45 days, the inclusion of taurine supplementation in diets improved the body weight gain (BWG), feed consumption (FC), and feed conversion ratio (FCR) of broilers (P < 0.05). In CBC tests, the experimental treatments were significantly different concerning the red blood cell (RBC) count, the average hemoglobin in the cell, the RBC width in the curve, and the hematocrit (P < 0.05). Despite the significance of oxidative stress among the treatments, the control and fourth treatments showed the highest and the lowest oxidative stress, respectively (P < 0.05). Also, in jejunum morphology, the fourth treatment showed the best performance in terms of villus length and width and the villus length to crypt depth (V/C) ratio (P < 0.05). Overall, 6g/kg taurine addition to the diet reduced oxidative stress and positive features in the jejunum morphology while improving the functional traits of broilers.

Metabolomic insights into the effects of seasonal shifts on the dynamic variation of non-volatile compounds of abalone (Haliotis discus hannai)

Abalone (Haliotis spp.) is a shellfish known for its exceptional nutritional value and significant economic worth. This study investigated the dynamic characteristics of non-volatile compounds over a year, including metabolites, lipids, nucleotides, and free amino acids (FAAs), which determined the nutritional quality and flavor of abalone. 174 metabolites and 371 lipids were identified and characterized, while 20 FAAs and 11 nucleotides were quantitatively assessed. These non-volatile compounds of abalone were fluctuated with months variation, which was consistent with the fluctuations of environmental factors, especially seawater temperature. Compared with seasonal variation, gender had less influence on these non-volatiles. June and July proved to be the optimal harvesting periods for abalone, with the levels of overall metabolites, lipids, FAAs, and nucleotides in abalone exhibiting a higher value in June and July over a year. Intriguingly, taurine covered 60% of the total FAAs and abalone could be used as dietary taurine supplementation.

Dietary Taurine Improves Growth Performance and Intestine Health via the GSH/GSSG Antioxidant System and Nrf2/ARE Signaling Pathway in Weaned Piglets.

Early weaning of piglets was prone to increase reactive oxygen species, disrupt the redox balance, decrease antioxidant capacity, cause oxidative stress and intestinal oxidative damage, and lead to diarrhea in piglets. This research aimed to study dietary taurine (Tau) supplementation at a level relieving intestinal oxidative damage in early-weaned piglets. A total of 48 piglets were assigned to four groups of 12 individuals and fed a basal diet with 0.0% Tau (CON), 0.2% Tau (L-Tau), 0.3% Tau (M-Tau), or 0.4% Tau (H-Tau), respectively. The animal experiment lasted 30 days. The final weight, weight gain, average daily gain, and feed conversion rate increased with the increase in dietary Tau (Linear, p < 0.05; Quadratic p < 0.05), while the diarrhea index of piglets decreased with the increase in dietary Tau (Linear, p < 0.05). Serum malondialdehyde, nitric oxide (NO), D-lactose, and oxidized glutathione (GSSG) concentrations decreased with the increase in dietary Tau (Linear, p < 0.05). The O2•- and •OH clearance rate in serum, liver, and jejunum mucosa increased with the increase in dietary Tau (Linear, p < 0.05). Serum superoxide dismutase (SOD) activity, glutathione peroxidase (GPX) activity, catalase (CAT) activity, and peroxidase (POD) activity and total antioxidant capacity increased with the increase in dietary Tau (Linear, p < 0.05). The serum glutathione (GSH) concentration and the ratio of GSH to GSSG increased with the increase in dietary Tau (Linear, p < 0.05). The POD and glutathione synthase activity in the liver and jejunum mucosa increased with the increase in dietary Tau (Linear, p < 0.05). The mRNA abundances of HO-1 and GPX1 in the H-Tau group were higher than that in the L-Tau, M-Tau, and CON groups (p < 0.05). The mRNA abundances of SOD1 and Nrf2 in the M-Tau and H-Tau groups were higher than in the L-Tau and CON groups (p < 0.05). The mRNA abundance of SOD2 in the L-Tau, M-Tau, and H-Tau groups was higher than in the CON group (p < 0.05). The VH and the ratio of VH to CD of jejunum and ileum increased with the increase in dietary Tau (Linear, p < 0.05). The mRNA abundances of occludens 1 and claudin 1 in the H-Tau group were higher than that in the CON, L-Tau, and M-Tau (p < 0.05). The mRNA abundance of occludin in the L-Tau, M-Tau, and H-Tau groups was higher than that in CON (p < 0.05). The abundance of Firmicutes increased with the increase in dietary Tau (Linear, p < 0.05), while Proteobacteria and Spirochaetota decreased with the increase in dietary Tau (Linear, p < 0.05). Collectively, dietary supplementation of 0.3% and 0.4% Tau in feed could significantly improve the growth performance and enhance the antioxidant capacity of piglets.

Dietary Taurine Supplementation Improves the Meat Quality, Muscle Fiber Type, and Mitochondrial Function of Finishing Pigs.

This study investigated the effects of dietary supplementation with taurine (TAU) on the meat quality, muscle fiber type, and mitochondrial function of finishing pigs. The results demonstrated that TAU significantly increased the a* value while decreasing b*45min, L*24h, and drip loss24h and drip loss48h in the longissimus dorsi (LD) muscle. Dietary supplemented with TAU reduced the content of lactate and the glycolytic potential (GP) in the LD muscle. Dietary supplemented with TAU enhanced the oxidative fiber-related gene expression as well as increased succinic dehydrogenase and malate dehydrogenase activities while reducing lactate dehydrogenase activity. Furthermore, dietary supplementation with TAU increased the contents of mtDNA and ATP and mitochondrial function-related gene expression. Moreover, TAU enhanced the mRNA expressions of calcineurin (CaN) and nuclear factor of activated T cells c1 (NFATc1) and protein expressions of CNA and NFATc1. The results indicate that dietary TAU supplementation improves meat quality and mitochondrial biogenesis and function and promotes muscle fiber-type conversion from the glycolytic fiber to the oxidative fiber via the CaN/NFATc1 pathway.

Effects of taurine supplementation in low fishmeal diet on growth, immunity and intestinal health of Litopenaeus vannamei

This experiment investigated the impact of taurine supplementation in low fishmeal diets on growth, antioxidant capacity, immunity and intestinal health of Litopenaeus vannamei. In this experiment, five diets were formulated, of which the high fishmeal diet contained 25% fishmeal (HF) and the remaining four diets were a mixture of soybean protein concentrate and Clostridium autoethanogenum protein (CAP) replacing 15% fishmeal and supplemented with 0%, 0.2%, 0.4% and 0.6% taurine (LF, T1, T2, T3). A total of 800 healthy shrimp (0.32 ± 0.00 g) were randomly allocated into 5 groups, with each group consisting of 4 replicates and 40 shrimp per replicate. The shrimp were fed four times a day for 51 days. The results showed that there was no significant difference in weight gain rate and survival (P＞0.05). Dietary taurine supplementation significantly improved the antioxidant capacity of shrimp. Compared with LF group, the mRNA expression of alf (anti-lipopolysaccharide factor) and cru (crustins) in HF group were significantly up-regulated (P＜0.05). Compared with the HF and LF groups, the mRNA expression of pen3 (penaeidins 3) in T1, T2 and T3 groups was significantly up-regulated, and the mRNA expression of dorsal in T2 group was significantly up-regulated (P＜0.05). The mRNA expression of bcl-2 (B-cell lymphoma-2) in T2 group was significantly up-regulated than that in other groups (P＜0.05). The mRNA expression of cyt-c (cytochrome c) in LF group was significantly up-regulated than that in other groups (P＜0.05). Compared with LF group, the mRNA expression of tnf-a (tumor necrosis factor-alpha) in HF, T2 and T3 groups was significantly down-regulated (P＜0.05). The mRNA expression of caspase8 in HF and T2 group was significantly down-regulated than that in other groups (P＜0.05). Compared with LF group, the mRNA expression of caspase3 in T1 groups was significantly down-regulated (P＜0.05). Intestinal H&E stained sections showed that dietary taurine supplementation improved intestinal mucosal folds height, width and muscle layer thickness. In general, dietary taurine supplementation can improve the antioxidant capacity, immunity and intestinal health of Litopenaeus vannamei, and the optimal supplemental level is 0.4%.

Transcriptome-based nutrigenomics analysis reveals the roles of dietary taurine in the muscle growth of juvenile turbot (Scophthalmus maximus)

The present study explored transcriptomics and gene regulation variations in the muscle of turbot fed with dietary taurine. A 70-day feeding trial was conducted using turbot (initial body weight: 3.66 ± 0.02 g) fed with different levels of dietary taurine: 0 % (C), 0.4 % (T2), 1.2 % (T4) and 2.0 % (T6). Two methods were used to analyze and verify the taurine effects on muscle growth: (1) real-time quantitative PCR (qRT-PCR) for the key muscle growth-related genes and (2) transcriptomic analysis by next-generation sequencing (NGS). The results showed that 1.2 % of dietary taurine supplementation significantly increased the expression of muscle growth stimulatory genes, including TauT, myoD, Myf5, myogenin and follistatin. And also, the 1.2 % level significantly decreased the expression of the muscle growth-restricting gene (myostatin). Meanwhile, transcriptomics analysis found that 1.2 % dietary taurine supplementation significantly increased the number of up-regulated genes linked to metabolic pathways. In contrast, taurine significantly enriched the actin cytoskeleton and metabolic pathways in the T4 and T2 groups, respectively. These findings align with the gene ontology (GO) analysis, which indicated a higher number of cellular component (CC) gene expressions at a 1.2 % of dietary taurine compared to a 0.4 % of dietary taurine supplementation. In conclusion, dietary taurine had positive impacts on the growth-stimulatory genes. Moreover, 1.2 % of dietary taurine supplementation is important to the metabolic pathway enrichment.

Dietary Taurine Intake Affects the Growth Performance, Lipid Composition, and Antioxidant Defense of Juvenile Ivory Shell (Babylonia areolata).

In this study, an eight-week feeding trial was performed to investigate the effects of different taurine supplementation levels (0.0% as control, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%) on the growth performance, lipid composition, and antioxidant ability in juvenile ivory shells Babylonia areolata. The results showed that taurine supplementation significantly improved the specific growth rates (SGRs) and survival rates of ivory shell (except the survival rate in the 3.0% taurine diet group) (p < 0.05). The SGRs showed an increasing and then decreasing tendency with increasing dietary taurine supplementation, and the highest value was observed in the 2.0% taurine diet (2.60%/d). The taurine content in the muscle of ivory shells fed taurine-supplemented diets significantly increased when compared to the control group (p < 0.05). The profiles of C22:2n6 in the muscle of ivory shells fed taurine-supplemented diets were significantly higher than in the control group (p < 0.05), and the highest values were observed in the 2.0% taurine supplementation group. The high-density lipoprotein cholesterol (HDL-C) content in the hepatopancreas showed an increasing and then decreasing tendency with increasing dietary taurine supplementation, while the low-density lipoprotein cholesterol (LDL-C) concentration showed a decreasing tendency. Furthermore, the activities of pepsin and lipase in both the intestine and hepatopancreas significantly increased at moderate taurine supplementation levels compared to the control group (p < 0.05). Accordingly, obvious increases in the histological parameters in the intestine of ivory shells fed taurine-supplemented diets were also found. As for the antioxidant ability, the activities of the total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) showed an increasing and then decreasing tendency with increasing dietary taurine supplementation, and the highest values were observed in the 1.0% and 1.0-2.0% taurine supplementation groups, respectively; the malondialdehyde (MDA) contents significantly decreased with increasing dietary taurine supplementation (p < 0.05). The taurine intake affected the expression of four appetite-related genes in the hepatopancreas, in which orexin and NPY showed an increasing and then decreasing tendency, while leptin and cholecyatoklnin decreased with increasing dietary taurine supplementation. In conclusion, moderate taurine supplementation in an artificial diet (about 1.5-2.0%) could improve the growth performance and antioxidant ability and change the lipid composition of juvenile ivory shells.

Taurine Supplementation to Plant-Based Diets Improves Lipid Metabolism in Senegalese Sole.

Taurine is a sulphur-containing amino acid with important physiological roles and a key compound for the synthesis of bile salts, which are essential for the emulsion and absorption of dietary lipids. This study aimed to evaluate the effects of taurine supplementation to low-fishmeal diets on the metabolism of taurine, bile acids, and lipids of Senegalese sole. A fishmeal (FM) and a plant-protein-based (PP0) diet were formulated, and the latter was supplemented with taurine at 0.5 and 1.5% (diets PP0.5 and PP1.5). Diets were assigned to triplicate tanks containing 35 fish (initial weight ~14 g) for 6 weeks. Fish from the PP0 treatment presented lower taurine and bile-acid concentrations compared with the FM treatment, and a downregulation of cyp7a1 and abcb11 was observed. Triolein catabolism decreased in PP0-fed fish, resulting in increased hepatic fat content and plasma triglycerides, while no effects on plasma cholesterol were observed. Taurine supplementation to plant-based diets resulted in a higher taurine accumulation in fish tissues, increased bile-acid concentration, and upregulation of cyp7a1 and abcb11. Hepatic fat content and plasma triglycerides decreased with increasing dietary taurine supplementation. Taurine supplementation mitigated part of the negative effects of plant-based diets, leading to better lipid utilisation.

Dietary taurine supplementation counteracts deoxynivalenol-induced liver injury via alleviating oxidative stress, mitochondrial dysfunction, apoptosis, and inflammation in piglets

Deoxynivalenol (DON), as a widespread Fusarium mycotoxin in cereals, food products, and animal feed, is detrimental to both human and animal health. The liver is not only the primary organ responsible for DON metabolism but also the principal organ affected by DON toxicity. Taurine is well known to display various physiological and pharmacological functions due to its antioxidant and anti-inflammatory properties. However, the information regarding taurine supplementation counteracting DON-induced liver injury in piglets is still unclear. In our work, twenty-four weaned piglets were subjected to four groups for a 24-day period, including the BD group (a basal diet), the DON group (3 mg/kg DON-contaminated diet), the DON+LT group (3 mg/kg DON-contaminated diet + 0.3% taurine), and the DON+HT group (3 mg/kg DON-contaminated diet + 0.6% taurine). Our findings indicated that taurine supplementation improved growth performance and alleviated DON-induced liver injury, as evidenced by the reduced pathological and serum biochemical changes (ALT, AST, ALP, and LDH), especially in the group with the 0.3% taurine. Taurine could counteract hepatic oxidative stress in piglets exposed to DON, as it reduced ROS, 8-OHdG, and MDA concentrations and improved the activity of antioxidant enzymes. Concurrently, taurine was observed to upregulate the expression of key factors involved in mitochondrial function and the Nrf2 signaling pathway. Furthermore, taurine treatment effectively attenuated DON-induced hepatocyte apoptosis, as verified through the decreased proportion of TUNEL-positive cells and regulation of the mitochondria-mediated apoptosis pathway. Finally, the administration of taurine was able to reduce liver inflammation due to DON, by inactivating the NF-κB signaling pathway and declining the production of pro-inflammatory cytokines. In summary, our results implied that taurine effectively improved DON-induced liver injury. The underlying mechanism should be that taurine restored mitochondrial normal function and antagonized oxidative stress, thereby reducing apoptosis and inflammatory responses in the liver of weaned piglets.

NKCC transport mediates the insulinotropic effects of taurine and other small neutral amino acids

AimsDespite its high concentration in pancreatic islets of Langerhans and broad range of antihyperglycemic effects, the route facilitating the import of dietary taurine into pancreatic β-cell and mechanisms underlying its insulinotropic activity are unclear. We therefore studied the impact of taurine on beta-cell function, alongside that of other small neutral amino acids, L-alanine and L-proline. Main methodsPharmacological profiling of insulin secretion was conducted using clonal BRIN BD11 β-cells, the impact of taurine on the metabolic fate of glucose carbons was assessed using NMR and the findings were verified by real-time imaging of Ca2+ dynamics in the cytosol of primary mouse and human islet beta-cells. Key findingsIn our hands, taurine, alanine and proline induced secretory responses that were dependent on the plasma membrane depolarisation, import of Ca2+, homeostasis of K+ and Na+ as well as on cell glycolytic and oxidative metabolism. Taurine shifted the balance between the oxidation and anaplerosis towards the latter, in BRIN BD11 beta-cells. Furthermore, the amino acid signalling was significantly attenuated by inhibition of Na+-K+-Cl− symporter (NKCC). SignificanceThese data suggest that taurine, like L-alanine and L-proline, acutely induces glucose-dependent insulin-secretory responses by modulating electrogenic Na+ transport, with potential role of intracellular K+ and Cl− in the signal transduction. The acute action delineated would be consistent with antidiabetic potential of dietary taurine supplementation.

Additional supplementation of sulfur-containing amino acids in the diets improves the intestinal health of turbot fed high-lipid diets

An eight-week feeding trial was conducted to investigate the effects of diets supplemented with three sulfur-containing amino acids (SAA), namely, methionine, cysteine, and taurine, on the intestinal health status of juvenile turbot (Scophthalmus maximus) fed high-lipid diets. Four diets were formulated, namely, a high-lipid control diet (16% lipid, HL) and three SAA-supplemented diets, which were formulated by supplementing 1.5% methionine (HLM), 1.5% cysteine (HLC), and 1.5% taurine (HLT) into the HL control diet, respectively. Each diet was assigned to triplicate tanks, and each tank was stocked with 30 juvenile fish (appr. initial weight, 8 g). The histological and morphometric results showed that dietary SAA supplementation obviously improved the intestinal morphology and integrity, in particular as reflected by higher height of microvilli and mucosal folds. Dietary SAA supplementation, in particular cysteine, up-regulated the gene expression of mucin-2 and tight junction proteins (ZO-1, Tricellilun and JAM). Dietary SAA supplementation remarkably down-regulated the gene expression of apoptosis-related factors such as p38, JNK, and Bax, expression of pro-inflammatory factors (e.g., NF-κB, AP-1 IL-1β, IL-8, and TNF-α). SAA supplementation resulted in higher antioxidative abilities in the intestine. Additionally, dietary SAA supplementation largely altered the communities of intestinal microbiota. Compared with the HL group, higher relative abundance of potential beneficial bacteria, and lower relative abundance of opportunistic pathogens were observed in SAA-supplemented groups. Dietary taurine supplementation significantly increased the relative abundance of Ligilactobacillus (in particular Lactobacillus murinus) and Limosilactobacillus (especially Lactobacillus reuteri). In conclusion, dietary sulfur-containing amino acids supplementation have promising potential in ameliorating the intestinal inflammation of turbot fed high-lipid diets. Especially dietary cysteine and taurine supplementation have more positive effects on the communities of the intestinal microbiota of turbot.

Improvement of Growth Performance, Hepatic and Erythrocyte Antioxidant Capacity, Innate Immunity, and Biochemical Parameters of Persian Sturgeon, Acipenser persicus, by Sulfur Amino Acids’ Supplementation

The present study was aimed at determining the effects of taurine and/or methionine addition to a plant-based diet on growth performance and immunological and antioxidant responses of Persian sturgeon, Acipenser persicus. Four plant-based diets were formulated, including control (C), control+1 g/kg taurine (T), control+2 g/kg methionine (M), and control+1 g/kg taurine and 2 g/kg methionine (T+M). Fish were fed each diet in triplicate for 70 days, and growth performance, hematological, plasma biochemical, and immunological parameters, and hepatic and erythrocyte antioxidant parameters were determined after that. Dietary taurine or methionine supplementation significantly increased growth performance, hematological parameters, antioxidant enzymes’ activities, plasma lysozyme, alternative complement, and total immunoglobulin but decreased plasma alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase activities, and malondialdehyde. Interaction additive effects of dietary taurine and methionine were observed in erythrocyte count, hematocrit, alternative complement, total immunoglobulin, hepatic malondialdehyde, superoxide dismutase, and glutathione peroxidase. In conclusion, dietary taurine (1 g/kg) and methionine (2 g/kg) supplementation is necessary to support higher growth rate, immunological responses, and antioxidant capacity in Persian sturgeon, when fed a plant-based diet. According to the present results, the highest performance is obtained when both amino acids are simultaneously added to the fish diet.

Taurine supplementation in plant-based diets for juvenile rainbow trout (Oncorhynchus mykiss): Effects on growth performance, whole body composition, and histomorphological features

Taurine supplementation in plant protein-based diets has been reported to improve growth performance, feed utilization, whole body composition, and gut integrity in carnivorous fish species, but data in rainbow trout are quite scarce. This study aimed to investigate the effects of plant protein-based diets supplemented with different levels of taurine on rainbow trout growth performance, whole body composition, and histomorphological traits of the intestine and main organs. In a 71-day trial, 340 juvenile rainbow trout were randomly distributed to 5 dietary treatments (4 replicate tanks/diet, 17 fish/tank): two control diets (a fishmeal-based diet [positive control; C+] and a soybean meal-soy protein concentrate-based diet [negative control; C-]), and three experimental diets in which the C-diet was supplemented with 2.5, 5 and 10 g/kg of taurine (T2.5, T5 and T10, respectively). At the end of the trial, growth parameters were assessed, and whole fish (12 pools of 3 fish/diet) and gut, liver and kidney samples (12 fish/diet) were collected for whole body composition and histomorphological analyses, respectively. Liver (8 fish/diet) was also sampled for taurine quantification. The fish fed the T10 diet showed higher weight gain, protein efficiency ratio, and specific growth rate – as well as decreased feed conversion ratio – when compared to the C+ group only (P < 0.05), thus suggesting a main effect of the taurine source on the response. The T2.5 rainbow trout showed lower moisture content and increased ether extract and ash contents than the other dietary treatments (P < 0.001). Higher crude protein content was also observed in fish fed the C- and T10 diets in comparison with the other groups (P < 0.001). Hepatic taurine levels were increased in the C+ group when compared to the C-, T2.5 and T5 diets (P < 0.05), with higher contents being also identified in the T10 group than the C- diet (P < 0.01). Differently, gut morphometric indices and histopathological features of the gut, liver, and kidneys were unaffected by dietary taurine supplementation (P > 0.05). In conclusion, dietary taurine supplementation in juvenile rainbow trout fed vegetable protein-based diet is capable of influencing the growth performance and the whole lipid content of the animals, without affecting the histomorphological traits of the intestine, the liver and the kidneys. In particular, the 2.5 and 10 g/kg supplementation levels seem to be capable of exerting the most pronounced effects in terms of composition of the fish body mass and growth parameters, respectively.

Taurine supplements in high-carbohydrate diets increase growth performance of Monopterus albus by improving carbohydrate and lipid metabolism, reducing liver damage, and regulating intestinal microbiota

An 8-week feeding trial was performed to investigate the effects of the addition of taurine to high-carbohydrate diets on growth performance, carbohydrate metabolism, lipid deposition, antioxidant ability, inflammation, and intestinal microbiota in juvenile Monopterus albus. Four diets were designed: a control diet (0% corn starch, CON), high-carbohydrate (40% corn starch, HC), and high-carbohydrate diets supplemented with 0.2 and 0.5% taurine (HCT0.2 and HCT0.5, respectively). Each treatment group had 3 replicates. The results showed that the HC feeding significantly decreased growth performance and gluconeogenesis, increased lipid deposition, glycolysis and liver inflammation, and disrupted the intestinal microbiota compared with the CON group. However, compared with the HC group, the addition of taurine to HC diets significantly increased growth performance and the activities of glycolysis and antioxidative enzymes, whereas the opposite occurred in the levels of triglyceride, low-density lipoprotein cholesterol, total cholesterol, and gluconeogenesis enzymes. Additionally, the addition of taurine to HC diets remarkably increased the mRNA expression levels of glycolysis, lipolysis, anti-inflammatory cytokine compared with the HC group, whereas the opposite occurred in the mRNA expression levels of antioxidative enzymes, gluconeogenesis, lipid accumulation, and pro-inflammatory cytokine genes. Besides, the relative abundance of Lactococcus in the HC group remarkably higher than those in the CON group, whereas the opposite occurred in the relative abundance of Clostridium sensu stricto 1. Compared with the CON group, 0.5% taurine supplementation in HC diets showed no significant different on the composition and diversity of intestinal microbiota. Based on the findings, HC diets induced negative effects on rice field eel, and dietary taurine supplementation can improve the growth performance, decrease lipid deposition, enhance antioxidant ability, reduce liver damage, and regulate the homeostasis of intestinal microbiota. And the optimum supplemental level of taurine was 0.5%.

The Lipid-Lowering Effect of Dietary Taurine in Orange-Spotted Groupers (Epinephelus coioides) Involves Both Bile Acids and Lipid Metabolism

An 8-week feeding trial was conducted to investigate how dietary taurine supplementation attenuates the lipid deposition induced by dietary high lipid in juvenile orange-spotted grouper (Epinephelus coioides). Three isonitrogenous (47% crude protein) semipurified diets were formulated to contain two levels of lipid and termed as 10% lipid diet, 15% lipid diet, and 15% lipid with 1% taurine (namely, diet 10L, diet 15L, and diet 15L + T, respectively). Groupers fed diet 15L + T showed higher weight gain and feed efficiency compared with diet 15L. Groupers fed diet 15L showed higher liver lipid contents, plasma total cholesterol (TC), and leptin contents vs. those fed diet 10L. Diet 15L + T decreased hepatosomatic index, liver lipid content, and plasma TC and adiponectin contents, and increased liver 3-hydroxy-3-methy1 glutary1 coenzyme A reductase content compared with diet 15L. Fish fed diet 15L had higher contents of chenodeoxycholic acid, deoxycholic acid, and lithocholic acid, and lower contents of glycodeoxycholic acid (GDCA), glycolithocholic acid, glycoursodeoxycholic acid, taurodeoxycholic acid (TDCA), and β-, γ-, and ω-muricholic acid (MCA) when compared with fish fed diet 10L. Diet 15L + T downregulated the contents of glycocholic acid, glycochenodeoxycholic acid, taurohyodeoxycholic acid, tauromuricholic acid, TDCA, ursodeoxycholic acid, GDCA, and β-MCA vs. diet 15L. Diet 15L upregulated expression of peroxisome proliferator-activated receptor α (pparα) gene but downregulated expression of acyl-CoA carboxylase (acc), fatty acid synthase (fas), and glucose-6-phosphate dehydrogenase (g6pd) genes in comparison with diet 10L. The gene expression level of fas and 6pgd was downregulated and the pparα gene expression level was upregulated in fish fed diet 15L + T compared with those in fish fed diet 15L. Overall, this study indicated that dietary taurine supplementation can attenuate the liver lipid deposition of groupers caused by feeding 15% lipid through accelerating lipid absorption of taurine-conjugated bile acids and fatty acid β-oxidation and inhibiting lipogenesis.

The optimal dietary taurine supplementation in zero fish meal diet of juvenile snakehead fish (Channa striata)

The most common alternative protein sources are plant-based proteins such as soybean meal but one of the limitations is taurine deficiency that can be especially detrimental for carnivorous fish. This study was to determine the important roles of dietary taurine on the growth performance, feed utilization and body composition of juvenile snakehead fish with an initial weight of 4.66–4.71 g/fish. Five test diets were investigated, using various taurine supplementation levels and both isonitrogenous and isoenergetic formulas: 1)control (fish meal inclusion); 2)zero fish meal diet (ZF) without taurine supplementation (T0); 3) ZF with taurine supplementation at 0.5% (T0.5); 4) ZF with taurine supplementation at 1.0% (T1.0); 5) ZF with taurine supplementation at 1.5% (T1.5). Fish were fed with five different dietary taurine levels for 60 days. Weight gain (WG), average daily gain (ADG) and specific growth rate (SGR) were higher in the control group of fish, followed by the T0.5 and T1.0 group but the lowest level was observed in fish fed the T0 and T1.5 (p < 0.05). The statistical results of Survival rate (SR), feed conversion ratio (FCR) and protein efficiency ratio (PER) were not significantly different (p > 0.05) among all experimental groups, whereas fish fed diet T0.5 and T1.0 had good trend in FCR and PER value similar to the control group. Dietary taurine might not affect on whole-body composition in juvenile snakehead fish (p > 0.0). Taurine accumulation in fish whole body and the liver both showed the increasing trends varying supplementation levels in each experimental diet. In the current study, taurine supplementation had no observable effects on the histological structures of liver and distal intestines of snakehead fish. This phenomenon indicated that the taurine supplementation at 0.5% in the plant protein-based diet (ZF) cloud be improved the growth performance and feed utilization of juvenile snakehead fish. Leading to, this is a positive sign of a possibility to reduce feed cost by completely taking fish meal out of a future commercial aquafeed for better aquaculture business sustainability.

Effects of taurine supplementation on growth performance and feed utilization in aquatic animals: A meta-analysis

Evidence from many studies indicates that taurine addition may yield an influence on growth in aquaculture animals. Nevertheless, the application efficacy of taurine remains inconsistent across studies. This meta-analysis was conducted to quantify the effects of dietary taurine supplementation on response variables in aquaculture animals, including final body weight (FBW), feed conversion ratio (FCR) and protein efficiency ratio (PER). Hedges' g effect size was computed to quantify the primary outcomes. The sensitivity and subgroup analyses were conducted to assess the robustness of the pooled estimates. Additionally, the effect of different moderators and variability across species was determined by several analyses. Meta-regression was conducted to appraise the effect of different taurine inclusion in diet and taurine content in basal diet on the response variables. The results indicated that taurine supplementation in the diets significantly increased FBW and PER and decreased FCR in fish. Moreover, taurine inclusion yielded larger effects on growth and feed utilization in marine fishes than freshwater fishes. For all species, ‘species’ and ‘basal taurine content in control group’ were two significant moderators on all response variables, and ‘fishmeal content in diet’ as moderator variable was significant in FBW and PER. Interestingly, the beneficial effect of taurine addition on growth performance and feed utilization was significantly reduced as the taurine level in the basal diet increased. In addition, dietary taurine requirement of aquaculture animals was estimated to 0.79% based on broken line regression between total taurine content in diet and FBW effect size.

Effects of dietary taurine supplementation in low fish meal feed on growth, digestibility, intestinal enzyme activities of rice field eel ( Monopterus albus )

Effects of dietary taurine supplementation in low fish meal feed on growth, digestibility, intestinal enzyme activities of rice field eel ( Monopterus albus )