Effect Of Dietary Taurine Supplementation Research Articles

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.

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 )

Effect of dietary taurine supplementation on metabolome variation in plasma of Nile tilapia

Taurine has been considered as an essential nutrient for many aquaculture species. While dietary taurine supplementation is highly recommended, novelty studies on taurine metabolism in fish are needed. The present study aimed to provide insight into the molecular mechanisms involved in multiple metabolome changes in Nile tilapia (Oreochromis niloticus) by studying plasma metabolic profile changes in response to graded levels of dietary taurine supplementation. The analysis used proton nuclear magnetic resonance-based metabolomics. Four groups of tilapias were fed with four diets supplemented with 0.0, 0.4, 0.8 and 1.2% taurine for 84 days. Fish plasma was sampled at multiple time points to provide an accurate snapshot of specific metabolic profiles during growth. Under the effect of taurine supplementation, 21 and 12 metabolites in tilapia plasma shown significant changes in terms of time-dependence and diet-dependence, respectively. These metabolic changes in tilapia plasma were mainly associated with energy and amino acid metabolism, lipids, nucleotides and protein metabolism. The results indicate that 0.8% taurine supplementation could significantly improve the carbohydrate synthesis, protein digestion and absorption, and fat deposition of tilapia and thereby promoted growth and development of tilapia.

Effect of dietary taurine supplementation on the growth and blood physiological parameters of juvenile pirarucu

ABSTRACT For some fish species, dietary taurine supplementation has been proven necessary in feeds with considerable utilization of vegetable proteins to substitute fishmeal. Pirarucu, Arapaima gigas feeds mainly on taurine-rich animal items in nature, therefore this study aimed to evaluate the effect of dietary taurine supplementation (0, 0.5, 1, 1.5 and 3%) on the growth and blood physiological parameters of juvenile pirarucu. A commercial feed was utilized as the basal diet for the experimental diets. Three hundred fish (20.8 ± 2.3 g) were randomly distributed in 15 tanks and fed for 28 days. At the end of the trial, dietary taurine supplementation did not affect fish growth, feed consumption and feed efficiency. The original amounts of taurine (0.18%) and methionine (1.13%) in the commercial feed (0% taurine diet) apparently sufficed to promote adequate pirarucu growth, with no variation noted in the main blood physiological parameters. Further studies to assess whether taurine is conditionally essential for the pirarucu fed methionine-deficient diets are needed to elucidate the functionality of this nutrient for the studied species.

Dietary taurine supplementation enhances growth and nutrient digestibility in giant grouper Epinephelus lanceolatus fed a diet with soybean meal

In the study, we evaluated the effects of dietary taurine supplementation on growth, tissue taurine concentrations, and nutrient digestibility in the giant grouper, Epinephelus lanceolatus, fed a diet containing soybean meal. The basal diet containing soybean meal (replacing 40 % of fish meal protein) was supplemented with taurine at 0 (control), 0.1, 0.3, 0.5, and 1 g/kg of the diet. An all-fish-meal diet was also included for comparison. In total, six experimental diets were each fed to triplicate groups of grouper (with an initial weight of 14.42 ± 0.07 g) in a recirculating rearing system for 8 wks. Weight gain was the highest in fish fed the all-fish-meal diet, followed by fish fed the diet with 1 g/kg taurine, and the lowest was in fish fed the diets with 0 and 0.1 g/kg taurine. Fish fed the all-fish-meal diet and the diet with 1 g/kg taurine had the highest muscle taurine concentrations, followed by the 0.5 g/kg taurine group, with the lowest in the ≤0.3 g/kg taurine groups. All of the taurine-supplemented groups (0.1–1 g/kg taurine) had higher apparent dry matter and lipid digestibility than fish fed the control diet. Results indicated that 1 g/kg of taurine supplementation in the diet improved growth and nutrient digestibility in giant grouper when the diet contained a high level of soybean meal.

Effects of taurine on growth performance, antioxidant capacity, and lipid metabolism in broiler chickens

To investigate the effects of dietary taurine supplementation on growth performance, antioxidant status, and lipid metabolism in broilers, 384 male broilers (Arbor Acres, 1 D of age) were randomly allocated into 4 groups with 8 replicates of 8 birds. Dietary treatments were supplemented with taurine at the level of 0.00, 2.50, 5.00, and 7.50 g/kg of the diet (denoted as CON, TAU1, TAU2, TAU3, respectively). The BW gain from 1 to 21 D and from 22 to 42 D were all increased linearly (linear, P < 0.001) by taurine supplementation. Throughout the trial period, the highest BW gain and favorable gain-to-feed ratio were observed in the TAU2 group. Taurine supplementation increased the antioxidant enzyme activities and decreased (linear, P < 0.001) the content of malondialdehyde in both serum and the liver of broilers and alleviated oxidative damage through enhancing (P < 0.05) the hepatic genes expression of nuclear factor erythroid-2–related factor 2 (NRF2), glutathione peroxidase (GPX), and heme oxygenase-1 (HO-1). Correspondingly, in serum, the activities of hepatic lipase and total lipase were decreased linearly and quadratically (linear and quadratic, P < 0.001) with the increasing inclusion of taurine in the diet. Meanwhile, in serum, the content of triglycerides was significantly decreased (P < 0.05), and except for TAU3, the total cholesterol content was also significantly decreased (P < 0.05) by taurine supplementation. In addition, the hepatic content of triglycerides was significantly decreased (P < 0.05) in the TAU1 and TAU2 groups. Compared with the CON group, the hepatic genes expression of adenosine monophosphate–activated protein kinase alpha (AMPKα), silent 1, (SIRT1) and carnitine palmitoyltransferase 1 (CPT-1) were all increased (P < 0.05), and sterol regulatory element-binding protein-1 (SREBP-1) expression was decreased (P < 0.05) in the TAU2 group. These results indicated that taurine supplementation improved the growth performance, antioxidant capacity, and lipid metabolism of broilers.

Effects of taurine supplementation on productive performance, nutrient digestibility and gene expression of nutrient transporters in quails reared under heat stress.

This study was conducted to examine the effects of dietary taurine supplementation on productive performance, nutrient digestibility, antioxidant status, and the gene expression of ileal nutrient transporters in laying quails reared under heat stress (HS). One hundred and eighty laying Japanese quails (Coturnix coturnix japonica) were fed a basal diet or basal diet supplemented with either 2.5 or 5g of taurine per kg of diet, and reared at either 22±2°C for 24h/d (thermoneutral, TN) or 34±2°C for 8h/d (HS) for 12 weeks. The quails reared under HS consumed less feed, produced less egg, and had lower dry matter, organic matter and crude protein apparent digestibilities compared with the quails reared under the TN condition (P=0.001). However, increasing taurine concentrations in the diet improved feed intake and egg production (P=0.001), but also the apparent digestibilities (P≤0.027) in quails reared under HS. The greater doses (5g/kg) of taurine resulted in more responses. The quails reared under HS had greater serum and liver MDA concentrations (P=0.0001) which decreased with dietary taurine supplementations, particularly greater doses. The gene expressions of ileal PEPT1, EAAT3, CAT1, CAT2, SGLT1, SGLT5, GLUT2, and GLUT5 decreased under HS conditions (P=0.001). However, supplementing taurine, in a dose-dependent fashion, to the diet of quails reared under HS resulted in increases in the gene expressions of the transporters (P<0.05) except for CAT1. The results of the present work showed that taurine supplementation, particularly with greater doses (5g/kg), to the diet of laying quails kept under HS acts as alleviating negative effects of HS, resulting in improvements in productive performance and nutrient digestion, and also upregulation of ileal nutrient transporters.

Taurine modulates protein turnover in several tissues of meagre juveniles

This study aimed to evaluate the modulatory effect of dietary taurine supplementation on protein turnover of meagre juveniles fed semi-purified plant-based diets. For that purpose, fish (3.2 ± 0.2 g) were fed with five isoproteic (61.2%), isolipidic (16.6%) and isoenergetic (21.9 kJ g−1) experimental diets supplemented with 0.5% (Tau0.5), 1% (Tau1), 1.5% (Tau1.5) and 2% (Tau2) taurine or not (Tau0) for 38 days. The resulting growth parameters, protein expression levels and the activity of several proteolytic markers involved in the two major degradation pathways in vertebrates (autophagy-lysosomal and ubiquitin-proteasome) were assessed in the liver, intestine and white muscle of meagre. Increasing dietary taurine concentrations promoted fish growth, feed utilization and whole-body protein, lipid and energy contents. Dietary taurine seemed to modulate the activity of cathepsins D and B in white muscle and cathepsin L in the liver. Although, no significant effects were observed on proteasome activity, 1% dietary taurine supplementation decreased the expression of the Psmb4 proteasome subunit in the liver of fish when compared to lower taurine concentrations. No taurine effects were detected on the proteolytic markers analysed in the intestine of meagre. Hsp70 expression levels were also not affected by any of the experimental dietary taurine concentrations. Overall, experimental diet Tau2 promoted the highest growth rate which can be explained by a significant decrease in protein degradation in the liver and white muscle preferentially via the autophagy-lysosomal pathway (cathepsins) over the ubiquitin-proteasome route.

Dietary taurine supplementation enhances antioxidative capacity and improves breast meat quality of broiler chickens

ABSTRACT1. The aim of this study was to determine the effect of dietary taurine supplementation on growth performance, meat quality and antioxidant responses in breast muscle of broiler chickens.2. A total of 72 Arbor Acres broiler chickens (28-day-old) with similar body weight were randomly allocated into two groups, and fed either 0 g/kg (control; C) or 5 g/kg taurine-supplemented diets (TS) for 14 days.3. The results showed that TS had no effect on growth performance or chemical composition of breast muscle in broilers. The drip and cooking losses were significantly decreased (P < 0.05), and the pH24h of breast muscle were increased (P < 0.05) in the TS group. Meanwhile, broilers in the TS group exhibited significantly higher (P < 0.05) scavenging activities of superoxide and 2,2-diphenyl-1-picrylhydrazyl radicals, and lower (P < 0.05) contents of carbonyl, malondialdehyde, and 4-hydroxynonenal. TS increased (P < 0.05) total antioxidant capacity and superoxide dismutase activities. Moreover, TS significantly upregulated (P < 0.05) the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1, NAD(P)H quinone dehydrogenase 1, superoxide dismutase, catalase, and glutathione peroxidase.4. These findings suggested that TS enhanced antioxidative capacity and improved breast meat quality of broilers via activating the Nrf2 pathway.

Effects of dietary taurine supplementation on growth performance, jejunal morphology, appetite-related hormones, and genes expression in broilers subjected to chronic heat stress

This study was aimed to elucidate effects of taurine supplementation on growth performance, jejunal histology, and appetite-related genes expressions of broilers under heat stress. A total of 144 broilers on 28 d were allocated to three groups with 6 cages each group, 8 broilers per cage. The experiment period is from 28 to 42 d of age. In normal control (NC) group, chickens were held at 22°C ambient temperature (thermoneutral) and fed a basal diet. In the heat stress (HS) group, chickens were raised to constant HS at 32°C and received a basal diet. In the HS+ taurine group, chickens were fed a basal diet with 5g/kg taurine supplementation. The results showed that HS group had lower average daily feed intake, average daily gain, higher feed/gain ratio compared with the NC group (P < 0.05), while taurine addition did not ameliorate the lowered growth performance. Cloacal temperatures and respiration rates in the HS and heat taurine group were higher (P < 0.05) than in the NC group. Heat stress treatment elevated (P < 0.05) the concentrations of ghrelin and cholecystokinin (CCK) in serum and intestine, together with peptide YY and somatostatin (SS) in the intestine after 7 or 14 d of heat exposure. In addition, HS damaged the jejunal morphology by shortening villus height and deepening crypt depth (P < 0.05), upregulated (P < 0.05) the mRNA expression of taste receptor type 1 member 1 (T1R1), taste receptor type 1 member 3 (T1R3), CCK and ghrelin in the intestine. Taurine supplementation significantly mitigated the impairment of jejunal morphology, decreased the concentrations of serum ghrelin, increased the concentrations of somatostatin and peptide YY in the duodenum, elevated the mRNA expression levels of CCK in the jejunum compared with the HS group. In conclusion, taurine exerted no positive effects on the growth performance, while mitigated the impairment of jejunal morphology, increased some anorexic hormones secretion and mRNA expression of appetite-related genes in the intestine of broilers subjected to HS.

Metabolic Effect of Dietary Taurine Supplementation on Grouper (Epinephelus coioides): A 1H-NMR-Based Metabolomics Study.

Taurine is an indispensable amino acid for many fish species and taurine supplementation is needed when plant-based diets are used as the primary protein source for these species. However, there is limited information available to understand the physiological or metabolic effects of taurine on fish. In this study, 1H nuclear magnetic resonance (NMR)-based metabolomic analysis was conducted to identify the metabolic profile change in the fish intestine with the aim to assess the effect of dietary taurine supplementation on the physiological and metabolomic variation of fish, and reveal the possible mechanism of taurine’s metabolic effect. Grouper (Epinephelus coioides) were divided into four groups and fed diets containing 0.0%, 0.5%, 1.0%, and 1.5% taurine supplementation for 84 days. After extraction using aqueous and organic solvents, 25 significant taurine-induced metabolic changes were identified. These metabolic changes in grouper intestine were characterized by differences in carbohydrate, amino acid, lipid and nucleotide. The results reflected both the physiological state and growth of the fish, and indicated that taurine supplementation significantly affects the metabolome of fish, improves energy utilization and amino acid uptake, promotes protein, lipid and purine synthesis, and accelerates fish growth.

Effects of Dietary Taurine Supplementation to Gilts during Late Gestation and Lactation on Offspring Growth and Oxidative Stress.

Simple SummaryPrevious studies showed that gilts had elevated oxidative stress during late gestation and lactation, and could affect offspring growth. Taurine (Tau) is an important regulator of oxidative stress and possesses growth-enhancing properties. Our results suggested that taurine supplementation during late gestation and lactation of gilts increased growth performance in piglets through improved milk quality of gilts and intestinal morphology and barrier function of offspring.Birth is one of the most important events of animal production agriculture, as newborns are abruptly forced to adapt to environmental and nutritional disruptions that can lead to oxidative damage and delay in growth. Taurine (Tau) is an important regulator of oxidative stress and possesses growth-enhancing properties. In the present study, we investigated the effects of dietary Tau supplementation in gilts during late gestation and lactation on the growth performance of piglets by assessing intestinal morphology and barrier function, and oxidative stress status. Sixteen gilts were randomly allocated to the Con (basal diet) and Tau (basal diet with 1% Tau) groups from 75 d of gestation to weaning. Maternal dietary Tau supplementation significantly increased weaning weight and average daily gain weight in piglets. Piglets in the Tau group had higher villus height and villus height-to-crypt depth ratio (VCR), ZO-1 protein expression, and secretory immunoglobulin A (sIgA) content in the jejunum. Meanwhile, Tau bebeficial affected the milk quality of gilts, as indicated by decreased malondialdehyde (MDA) concentration and increased total superoxide dismutase (T-SOD), total antioxidative capability (T-AOC), glutathione peroxidase (GPx), and catalase (CAT) activity. Furthermore, Tau supplementation increased T-SOD activity in plasma and SOD2 protein expression in the jejunum in the piglets. In conclusion, this study provides evidence that dietary Tau supplementation to gilts improves growth performance in piglets, owing to improved intestinal morphology and barrier function, as well as inhibition of oxidative stress.

Effects of Dietary Taurine Supplementation on Blood and Urine Taurine Concentrations in the Elderly Women with Dementia.

The purpose of this research is to investigate the effects of dietary taurine supplementation on blood and urine taurine concentrations of the elderly women with dementia. Subjects were 31 female elderly with dementia hospitalized in a geriatric hospital. They were divided randomly into control group and dietary taurine supplemented group. Basically, same meals were served to both groups. Scorched rice water without taurine were served to control group. Scorched rice water containing 3g of taurine were reserved to taurine group with lunch similarly. Food ingredients containing high concentration of taurine were eliminated from the meal menu. Blood and urine samples were obtained from each subject at the beginning of study, after 2week and 4weeks in the morning fasting state. Taurine concentrations in serum and urine were measured as taurine-fluorescamine derivatives using high performance liquid chromatography (HPLC). Data were analyzed using SPSS 20.0. The average taurine concentrations in serum and urine of subjects were 89.2±9.5μM and 876.7±97.1μM at the beginning. After 4weeks, the taurine concentrations in serum and urine of dietary taurine supplemented group were 218.0±15.6μM and 6502.6±380.6μM, which were significantly higher compared to control group. Dietary taurine supplemented group showed positive changes in the score on language and execute performance. So taurine supplementation can provide beneficial effects to the elderly and the elderly with dementia.

Effect of dietary taurine supplementation on growth performance, digestive enzyme activities and antioxidant status of juvenile black carp (Mylopharyngodon piceus ) fed with low fish meal diet

An 8-week feeding trial was conducted to determine the effects of dietary taurine supplementation on growth performance, activities of digestive enzymes, antioxidant status and the target of rapamycin (TOR) gene expression in black carp (initial body weight 5.94 ± 0.02 g) fed with low fish meal diet. Six isonitrogen and isolipidic diets were formulated. High fish meal–based diet (HFM) contained 20% fish meal and 24% soybean meal as a positive control. Fifty per cent of fish meal in HFM was replaced by soybean meal and were supplemented with 0, 0.05%, 0.1%, 0.2% and 0.4% dietary taurine respectively (designated as T0.00 (a negative control), T0.05, T0.1, T0.2 and T0.4). The results showed that the partial replacement of fish meal by soybean meal without taurine supplementation resulted in a significant reduction in weight gain (WG), activities of amylase and lipase in intestine, superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) in serum, with a significant increase in feed conversion rate (FCR), the content of malonaldehyde (MDA), triglyceride (TG) and total cholesterol (TC) in serum. WG in groups supplemented with equal or above to 0.1% dietary taurine was significantly higher compared with T0 group. With increasing levels of dietary taurine, the activities of amylase, lipase, GSH-px and SOD and glutataione (GSH) content significantly increased (p < 0.05). FCR, the content of MDA, TG and TC in serum and crude lipid content in whole body were significantly reduced after taurine treatment (p < 0.05). In liver, TOR mRNA expression in groups with equal or above to 0.1% taurine was significantly higher than T0 group (p < 0.05).

Effect of dietary taurine supplementation on growth, digestive enzyme, immunity and resistant to dry stress of rice field eel (Monopterus albus) fed low fish meal diets

This study was conducted to evaluate the effect of dietary taurine supplementation on growth, immunity and resistant to dry stress of rice field eel (Monopterus albus) fed low fish meal diets. Six isonitrogenous and isolipid diets (32% fish meal) supplemented with six taurine concentrations (0, 0.3, 0.6, 0.9, 1.2 and 1.5 g/kg; designated as T0, T0.03, T0.06, T0.09, T0.12 and T0.15 groups, respectively) were prepared. A diet including 42% fish meal (FM group) was also included as a reference. The results showed that specific growth rate (SGR) in FM group was significantly higher than that in lower fish meal treatments. SGR significantly increased and slowly decreased with the increase in taurine supplementation level. Lipase activity value in intestine of M. albus fed FM diet was maximum, and with the increase in taurine supplementation level, lipase activity significantly increased and slowly decreased. The FM group had relative higher total antioxidant capacity (T-AOC) content, catalase (CAT), total superoxide dismutase (T-SOD), and lyzozyme (LZM) activities in serum than the other groups. With the increase in dietary taurine supplementation level, the CAT, T-SOD, T-AOC and LZM activities in serum significantly increased and then decreased. In the dry stress experience, the adrenaline (AD), cortisol (COR), glucose (GLU), total cholesterol (CHOL), and malondialdehyde (MDA) concentrations, T-AOC content, CAT and T-SOD activities in serum of M. albus in the four groups first increased and reached the peak at 2 hr, and then decreased under air-exposure stress. Compared to the FM group, T0.15 group had relative higher T-AOC content, CAT and T-SOD activities, and lower AD, COR GLU, TC and MDA concentrations.

Effects of dietary taurine supplementation on growth, feed efficiency, and nutrient composition of juvenile sablefish (Anoplopoma fimbria) fed plant based feeds

Abstract Juvenile sablefish were fed a low taurine, basal feed with seven graded levels of supplemental taurine to determine taurine requirements for growth and feed efficiency. The basal feed was plant based, formulated primarily with soy and corn proteins with a minimal (9%) amount of fishmeal. The unsupplemented, basal feed contained 0.14% taurine. Experimental feeds were supplemented with 0, 0.25, 0.50, 1.0, 1.5, 3.0, and 6.0% taurine. Using the five parameter, saturated kinetic model (5 SKM), peak weight gain was predicted at 1.5% dietary taurine. Optimum weight gain, as defined as the region of the 5 SKM curve corresponding to at least 95% of peak, was predicted between 0.4% and 5.8% dietary taurine. Peak feed efficiency was predicted at 1.1% dietary taurine with optimum weight gain predicted between 0.4% and 4.2%. Whole body and muscle tissue protein and lipid content were not affected by taurine supplementation. Tissue taurine content increased asymptotically with increasing dietary taurine supplementation. Whole body tissue became saturated at 0.25 ± 0.02% taurine, expressed on a wet weight basis. Muscle tissue became saturated at 0.34 ± 0.02% taurine. Results from this study should increase the performance of alternative, plant based feeds formulated for sablefish and enable regulatory agencies better estimate the potential human exposure to taurine from the consumption of sablefish receiving these feeds.

Effects of Taurine Supplementation on the Growth Performance of Juvenile Rock Bream Oplegnathus fasciatus

An 8-week feeding trial was conducted to investigate the effects of dietary taurine supplementation on the growth performance of juvenile rock bream, Oplegnathus fasciatus. Triplicate groups of 25 fish averaging <TEX>$2.72{\pm}0.04$</TEX> g (<TEX>$mean{\pm}SD$</TEX>) were fed one of six experimental diets prepared by adding taurine at 0%, 0.25%, 0.5%, 1.0%, 1.5% and 3.0% (Control, <TEX>$Tau_{0.25}$</TEX>, <TEX>$Tau_{0.5}$</TEX>, <TEX>$Tau_{1.0}$</TEX>, <TEX>$Tau_{1.5}$</TEX> and <TEX>$Tau_{3.0}$</TEX>, respectively). At the end of the feeding trial, the weight gain, specific growth rate and protein efficiency ratio of fish fed the <TEX>$Tau_{0.5}$</TEX>, <TEX>$Tau_{1.0}$</TEX> and <TEX>$Tau_{1.5}$</TEX> diets were significantly higher (P < 0.05) than those of fish fed the Control and <TEX>$Tau_{0.25}$</TEX> diets. The feed efficiency of fish fed the <TEX>$Tau_{0.5}$</TEX> diet was significantly higher than that of fish fed the Control, <TEX>$Tau_{0.25}$</TEX> and <TEX>$Tau_{3.0}$</TEX> diets. Fish fed the <TEX>$Tau_{1.0}$</TEX> diet had higher whole-body crude protein content than fish fed the Control diet, while the crude lipid content of fish fed the <TEX>$Tau_{1.5}$</TEX> and <TEX>$Tau_{3.0}$</TEX> diets was significantly lower than that of fish fed the Control and <TEX>$Tau_{0.25}$</TEX> diets. An ANOVA suggested that the optimum level of dietary taurine supplementation to improve growth and reduce the body lipid contents of juvenile rock bream, O. fasciatus, was 0.5%, while a broken line analysis of weight gain indicated a level of 0.62%.

Taurine is an essential nutrient for juvenile parrot fish Oplegnathus fasciatus

Two consecutive feeding trials were conducted to investigate taurine essentiality and requirement for parrot fish (Experiment I) and to determine whether taurine supplementation to high soybean meal (SM) diets would improve its growth performance (Experiment II). In Exp I, a fish meal (FM) based diet was used as a control and supplemented with 0.2, 0.4, 0.8, 1.2 or 1.6% taurine, and fed to triplicate groups of juvenile parrot fish (initial body weight, 13.5g) to apparent satiation for 8weeks. The growth and feed utilization were significantly improved by taurine supplementation up to 0.8% and thereafter plateaued. An optimum dietary taurine level was determined by a broken-line regression analysis based on weight gain and estimated at 0.88% diet. In Exp II, six experimental diets were prepared by supplementation of 0 or 1.0% taurine to a FM-based diet or addition of 0, 0.1% (low), 1.0% (medium) or 2.0% (high) taurine to a basal diet in which 30% of FM was replaced with SM (designated as FM, FM+T1, SM, SM+T0.1, SM+T1 and SM+T2, respectively). Each experimental diet was fed to juvenile parrot fish (initial body weight, 6.4g) twice daily to apparent satiation for 12weeks. The fish fed SM diet showed significantly lower growth performance compared to fish fed FM-based diets. Supplementation of taurine to SM diet significantly affected fish growth and higher performances were observed in fish fed SM+T1 or SM+T2 diets that were comparable to that of the fish fed FM diet. However, no significant changes were observed regarding the inclusion of taurine into FM-based diet. These results clearly demonstrated the positive effects of dietary taurine supplementation on feed utilization and growth performance of juvenile parrot fish when 30% FM was replaced with SM. The optimum dietary level of taurine seems to be approximately 1% in diets.

Is dietary taurine supplementation beneficial for gilthead seabream (Sparus aurata) larvae?

This study evaluated the effect of dietary taurine supplementation on the growth performance and methionine metabolism of gilthead seabream larvae. For this purpose, a growth experiment was carried out in which seabream larvae were fed upon rotifers supplemented with “blank” or taurine-enriched liposomes. A complementary trial was also done in which seabream larvae fed with live prey were subsequently tube-fed a solution containing a L-[U-14C] methionine with or without a taurine supplement. Results from the growth experiment showed that rotifers were successfully enriched with taurine, but no effects were observed on larval growth performance, survival or amino acid composition. Furthermore, dietary taurine supplementation did not result in an increase of larval taurine levels, a factor that may have been determinant for the absence of effects observed on growth performance. In the tube-feeding trial, results showed that dietary taurine supplementation led to an increase of methionine retention in larvae. These findings suggest the existence of an active taurine biosynthesis pathway for gilthead seabream during the larval stage. Hence, gilthead seabream may not be dependent on dietary taurine to maintain the taurine body pool, since it may convert taurine from methionine if required. Taken together, the results from this study indicate that dietary taurine supplementation does not seem to enhance the larval growth performance in fish species able to biosynthesise taurine during this stage, which seems to be the case of gilthead seabream. However, this study also showed that in these species, dietary taurine supplementation may ultimately affect larval metabolism by increasing methionine availability for several important physiological purposes, contributing to a better understanding on the role of taurine during the early life stages of fish development.