Cellular activity and development of enteric,hepatic and muscle tissues of juvenile pacu Piaractus mesopotamicus (Holmberg 1887) fed with lyophilized bovine colostrum

Bovine colostrum, an alternative food of animal origin provided as partial protein source, may constitute an innovative ingredient in fish feeding. Serum insulin‐like growth factor 1 (IGF‐1) and cellular activity of enteric, hepatic and muscle tissues of juvenile pacu Piaractus mesopotamicus fed with lyophilized bovine colostrum (LBC) were evaluated. Pacu (8.46 ± 0.74 g; 7.75 ± 0.27 cm, n = 18 in triplicate) were stocked into 18 tanks (300 L; 18 fish per tank, in triplicate) and fed with control diet containing 0% of LBC or experimental diet containing 10% and 20% of LBC inclusion for either 30 or 60 days of experiment. IGF‐1 serum concentration was not affected (P > 0.05) by the diet containing LBC and experimental period. The intestinal and hepatic cellular activity was not influenced by LBC (P > 0.05); however, intestine protein/RNA decreased at 60 days (P < 0.05). The muscle cellular activity was affected by LBC, highest in fish fed with diet containing 10% of LBC (P < 0.05). Between the periods DNA and protein/RNA increased at 60 days, while RNA, protein/DNA and RNA/DNA ratio decreased in this same period (P < 0.05). Increased DNA muscle content indicates fish growth by hyperplasia. The results of the present study is related with suitable development of enteric, hepatic and muscle tissues and proper condition of juvenile pacu fed with LBC considering the absence of differences in relation to juveniles that consumed diet without colostrum.     

Growth performance of juvenile pacu (Piaractus mesopotamicus) and dourado (Salminus brasiliensis) fed with lyophilized bovine colostrum

Growth performance was evaluated in juvenile pacu (Piaractus mesopotamicus) and dourado (Salminus brasiliensis) fed diets containing 0%, 10% and 20% of lyophilized bovine colostrum for 60 days. The performance variables of weight gain, relative weight gain, feed intake, feed conversion ratio, specific growth rate, total protein intake and protein efficiency ratio were evaluated as well as apparent digestibility coefficients of protein and energy in the diets. Inclusion of bovine colostrum did not induce differences in the performance of pacu and dourado (P > 0.05), indicating that the diets were adequate and met the nutritional needs of the juveniles. The protein digestibility in both species was improved with the inclusion of the bovine lacteal secretion. Based on the variables studied, the diets with lyophilized bovine colostrum inclusion were nutritionally suitable for both pacu and dourado indicating the possibility to use this lacteal secretion as a partial substitute of dietary protein.     

Dietary organic acids blend alone or in combination with an essential oil on the survival,growth, gut/liver structure and de hemato‐immunological in Nile tilapia Oreochromis niloticus

This study evaluated the effects of dietary supplementation of organic acids blend (OAB) alone or in combination with essential oil, Lippia origanoides (OAE) for Nile tilapia fed supplemented diets for 30 days. Fish (1.1 ± 0.04 g) were fed control (Control), or OAB 0.5% or OAB 0.5% + essential oil 0.125% (OAE) respectively. At the end of the experiment, samples were collected for de hemato‐immunological, histological analysis of the intestine and liver, as well as microbiology of the intestine. The pH of the diets supplemented with OAB and OAE reduced 0.92 and 0.19 respectively. The growth and FCR were unaffected by the treatments, but survival was significantly higher in the OAB treatment. Fish fed the OAB diet showed reduced concentration of total heterotrophic bacteria and Pseudomonas sp. in the intestine. Increased glucose in fish fed OAB and high number of circulating monocytes in fish fed OAE diet were observed. The anterior intestine of fish fed OAE diet showed larger number of goblet cells and increased villi height. The diet supplemented with OAB, mainly, improved the intestinal health and survival of tilapia juveniles and can be used in juvenile production.     

Growth performance,haematology and intestinal histo‐morphology of Nile tilapia fed on Indian Lotus (Nelumbo nucifera Gaertn.) leaf powder at different concentrations

Indian lotus, Nelumbo nucifera (Gaertn.) is a valued medicinal plant that exhibits several pharmacological properties. The present work aimed to investigate the effect of Indian lotus as a feed supplement on the growth performance, haematological and biochemical indices, and intestinal histo‐morphology of Nile tilapia (Oreochromis niloticus L.). The fish were randomly distributed into four groups and fed on a basal diet containing Indian lotus leaf powder at different concentrations (0, 0.1, 0.2 and 0.4%) for up to 60 days. The results elucidated that Indian lotus supplemented diets (0.2% and 0.4% followed by 0.1%) significantly improved weight gain, specific growth rate (%) and feed conversion ratio (p < .05). The feed intake was significantly increased in the fish fed on the Indian lotus supplemented diets in a dose‐dependent manner (p < .05). However, Indian lotus had no significant effect (p > .05) on survival rate, total erythrocytes (RBCs) count, haemoglobin (Hb) and hematocrit value (PCV, %) except a significant reduction on Hb content of the fish fed on 0.2% Indian lotus and a significant increase in PCV (%) in the fish fed on 0.1% Indian lotus (p < .05). The total leucocytes (WBCs), neutrophils and lymphocytes counts displayed significant elevations in the fish fed on the Indian lotus diets especially at 0.2% and 0.4%, whereas significant reduction in neutrophils count in the fish fed on 0.1% Indian lotus (p < .05) was observed. The serum glucose was significantly decreased in the fish fed on Indian lotus (0.1% and 0.2%), whereas cholesterol and triglycerides were markedly increased in the fish fed on the Indian lotus supplemented diets (p < .05). Moreover, the intestinal villous heights and the numbers of goblet cells and intraepithelial lymphocytes (IEL) were significantly boosted in all parts of the intestine in all Indian lotus diet groups as compared with the control group. However, as an exception, villous heights in the middle part of the intestine in the fish fed on 0.1% and 0.4% diets (p < .05) were not affected. In the proximal part, the villous heights and the numbers of goblet cells were markedly increased in fish fed on 0.2% and 0.4% diets followed by 0.1% diet. The fish fed on 0.2% lotus supplemented diet followed by 0.1% and 0.4% supplemented diets exhibited significant elevations in villous heights in the distal part and the numbers of goblet cells in the middle part of the intestine. There were no significant differences between the fish fed on the supplemented diets in the numbers of goblet cells in the distal part and the numbers of IEL in the proximal and middle parts (p > .05). In the distal part, the numbers of IEL revealed a significant elevation in 0.4% lotus supplemented diet followed by 0.1% and 0.2% lotus supplemented diet groups (p < .05). Therefore, this study indicates the advantageous effect of the Indian lotus leaves as a natural feed additive for improving growth, intestinal structure and hence, health status of Nile tilapia.     

Effect of in vitro exposure to Vibrio vulnificus on hydroelectrolytic transport and structural changes of sea bream (Sparus aurata L.) intestine

The everted gut sac technique has been used to investigate the effect of Vibrio vulnificus on water and electrolyte (Na⁺, K⁺, Cl⁻, HCO₃ ⁻) transport on the intestine of sea bream (Sparus aurata L.). Both the anterior and the posterior intestine were incubated in a medium containing 10⁸ V. vulnificus cells ml⁻¹ at 25°C for 2 h. The presence of V. vulnificus resulted in a significant reduction (P < 0.05) of water absorption in the anterior intestine, while sodium absorption in the anterior (P < 0.01) and posterior (P < 0.05) intestine was elevated. Chloride absorption was increased, but the changed was not significant, while potassium absorption decreased significantly (P < 0.05), but only in the posterior intestine. Incubation the sea bream intestine with V. vulnificus did not affect carbonate secretion in the anterior segment, whereas high secretion was stimulated in the posterior segment (P < 0.01). Histological evaluations demonstrated damage in the anterior intestine of sea bream that was characterized by the detachment of degenerative enterocytes, alterations in the microvilli, and the presence of a heterogenous cell population, indicating inflammation. Based on our results, we conclude that V. vulnificus caused cell damage to the intestine of sea bream and that the anterior intestine is more susceptible than the posterior part of the intestine. Several hypotheses are suggested to explain our observations, such as the presence of higher numbers of villosities in the anterior intestine than in the posterior one and/or the presence of endogenous bacteria in the posterior intestine which may have a protector role.     

Effect of cyclical feeding on compensatory growth,nitrogen and phosphorus budgets in juvenile Litopenaeus vannamei

This study assessed the effect of cyclical feeding on compensatory growth, nitrogen (N) and phosphorus (P) budgets of juvenile Litopenaeus vannamei. A 36‐day growth trial was performed with four different feeding protocols. The control group (S0) was fed to satiation twice every day during the whole experimental period; treatment groups S1, S2 and S3 were fed by the 9, 5 and 3 cycles of 1:3, 2:5 and 3:9 (fasting days:feeding days) respectively. Fasting in S1, S2 and S3 groups did not change the specific growth rate in wet weight (SGR_w), but the feed conversion efficiency (FCE) and protein efficiency ratio (PER) were significantly increased (P < 0.05) in comparison with control. The N and P consumed per unit wet weight gain of shrimp in S1, S2, S3 groups were significantly lower (P < 0.05) than control group by 15.39%, 15.96%, 19.33% for N, and 15.16%, 15.98%, 19.26% for P respectively. The total discharge of N and P (including N and P discharged by faeces (F_N/P), non‐faecal excretions (U_N/P) and exuviations (E_N/P); ) was significantly lower (P < 0.05) in the experiment groups by 19.91–22.07% for N and 18.68–26.37% for P respectively. Overall, the results suggest that the L. vannamei can reach completely compensatory growth, and the total discharge of N and P per unit wet weight gain of L. vannamei significantly decreased by cyclical feeding, which could have a positive effect on the reduced of environmental N and P loading due to the cultured of L. vannamei.     

Protein‐sparing effects and LPL gene expressions of dietary lipids in the juvenile soft‐shelled turtle,Pelodiscussinensis

The aim of this study was to evaluate the effects of dietary lipids on protein‐sparing and lipoprotein lipase (LPL) mRNA expression in culture using 360 juvenile soft‐shelled turtles (Pelodiscussinensis) (initial weight 4.26 ± 0.14 g). The turtles were allotted to six diets with three duplicates for 60 days. A control diet with 46% protein and 55% fishmeal (CD) and five isonitrogenous diets with 41.3% protein and 45% fishmeal (F, S, L1, L2 and L3) were used, containing the following three lipid types: fish oil, soybean oil and mixed oils (soybean oil: fish oil = 1:1). The results showed that the survival rate was not affected by dietary lipids (P > 0.05). The highest weight gain and lowest feed coefficient ratio were seen in the L3 diets (P < 0.05). Turtles fed with L2 and L3 diets had lower superoxide dismutase activities, higher alanine aminotransferase activities and higher cholesterol concentrations than those exposed to other diets (P < 0.05). Hepatic LPL activity and LPL mRNA expression were higher in the L3 diets than in the other diets (P < 0.05). Overall, there were obvious protein‐sparing effects of dietary lipids and LPL mRNA expression was stimulated by high dietary lipids in soft‐shelled turtles in this study.     

黄条鰤幼鱼胃排空特征、消化酶活性及摄食调控基因表达

为阐明黄条鰤幼鱼摄食消化特性，构建最佳胃排空数学模型，确立最适摄食投喂间隔，实验检测了黄条鰤幼鱼[(63.96±5.63) g]胃排空过程中内容物质量、肝脏和肠道中消化酶活性变化，分析了垂体中摄食调控相关基因的表达，比较了线性模型、平方根模型、立方模型3种数学模型对胃排空曲线的拟合程度。结果显示，黄条鰤在摄食后瞬时胃内容物湿重呈阶段性降低，18 h后降为0，属于直线下降型胃排空类型。胃排空过程中，肝脏淀粉酶、脂肪酶和糜蛋白酶活性呈先上升后下降、随后又上升接着下降的“M”型变化趋势，淀粉酶活性在摄食后0～6 h显著上升，脂肪酶和糜蛋白酶活性在0～9 h显著上升。三种酶活性在9～12 h均呈显著下降趋势，在15～18 h显著上升，且在18 h活性达到最高；肠道中的淀粉酶在0～6 h显著上升，随后下降，9～12 h呈上升趋势，12 h活性达到最高，随后逐渐下降，其脂肪酶和糜蛋白酶活性则是在摄食后0～12 h显著上升，12 h活性达到最高，随后逐渐下降。神经肽Y (npy)和食欲素(ore) mRNA表达水平呈先上升后下降趋势，npy在摄食后12～15 h内表达水平显著上升，ore在9～15 ...     

Dietary nucleotides enhance growth performance,feed efficiency and intestinal functional topography in European Seabass (Dicentrarchus labrax)

Nucleotides, nucleosides and nucleic acids (NU) have many critical functions in supporting life and increasing evidence suggests that exogenous supply can benefit the health of mammals and fish. For these reasons, a 6‐week feeding trial was conducted on juvenile European seabass (Dicentrarchus labrax) with diets containing 0%, 0.15% and 0.3% inclusion of a NU mixture (Laltide^®) derived from the yeast Saccharomyces cerevisiae. At the end of the study no significant differences were found in fish performance, although a tendency towards better performance was indicated in fish fed the Nu0.3 diet. In relation to histological assessment, a significantly greater perimeter ratio; internal to outer (IP/OP) was observed in the posterior intestine of fish fed supplemental NU. Microvilli heights in the posterior intestine were also shown to be significantly promoted in fish fed NU diets (p < 0.05). Goblet cell abundance was shown to be unaffected by the inclusion of NU in the diet (p > 0.05). Overall, this study indicates that orally administered NU may be effective promoters of gut functional topography with marginal associated improvements to fish performance. Nonetheless, longer exposure and/or commercial scale application, and in diets that were challenging in use of high inclusion levels of plant by‐products would potentially amplify improvements in production characteristics, in turn benefiting fish culturists.     

The specific dynamic action of southern catfish, <Emphasis Type="Italic">Silurus meridonalis</Emphasis> Chen,fed diets containing either raw or precooked corn starch or glucose

The growth performance of carnivorous southern catfish (Silurus meridionalis) was lower when fed a diet containing glucose as a carbohydrate source than when fed one containing starch. To test whether this decreased growth performance was partly due to higher metabolic costs induced by the fast assimilation of dietary glucose, the postprandial metabolic responses of southern catfish juvenile (36.7 ± 1.9 g) fed diets containing either raw or pre-cooked corn starch and glucose were investigated at 27.5°C. The peak metabolic rate of fish fed a raw corn starch diet was significantly higher than that of fish fed precooked corn starch and glucose diets (P < 0.05). The specific dynamic action (SDA) coefficients (energy expended on SDA as a percentage of energy content of the meal) of fish fed raw or precooked corn starch diets were significantly higher than that of fish fed a glucose diet (P < 0.05). The postprandial metabolic rate of fish fed a raw starch diet displayed a classic response – increased metabolic rate immediately after feeding, followed by a decreased metabolic rate several hours after feeding – as has been documented earlier in this species. However, the postprandial metabolic rate of fish fed a glucose diet had two alternating cycles of increasing and decreasing metabolic rate, which has not been reported previously. This bimodal pattern of the SDA curve was also found in a subsequent experiment in which purified d-glucose (0.1 g dry mass) was packed into sections of grass carp (Ctenopharyngodon idellus) intestine (0.05 g dry mass). The results suggest that the digestibility and absorption speed of the dietary carbohydrate has a significant effect on postprandial metabolic response in juvenile southern catfish. The results of this study may provide useful data in terms of the utilization of dietary carbohydrates by carnivorous fishes.     

Effect of dietary mannan oligosaccharide on growth,body composition,haematology and biochemical parameters of Asian seabass (Lates calcarifer)

A feeding trial was conducted to study the effect of mannan oligosaccharide (MOS) supplementation on growth, body composition, haematology, biochemical parameters and histology of Asian seabass (Lates calcarifer) fingerlings (8.13 ± 0.06 g average weight). Mannan oligosaccharide was supplemented at five different concentrations viz., 0%, 0.5%, 1%, 1.5% and 2% levels in the diet (40% protein and 9% lipid) of L. calcarifer. The results of the 60 days feeding trial showed that there was a significant (P < 0.05) increase in the final body weight, weight gain (WG), WG%, average daily gain, survival, specific growth rate, daily growth coefficient, hepatosomatic index and viscerosomatic index in the fish fed diet containing 1% MOS. Whole body composition of post‐fed animals showed non‐significant differences (P > 0.05) among the various treatment groups. The analysis of haematological parameters showed that there was no significant (P > 0.05) differences among different treatments but for the haemoglobin content which was significantly (P < 0.05) higher in the fish fed 1% MOS. Biochemical parameters revealed that glucose, urea, cholesterol and triglyceride content showed significant (P < 0.05) difference between control and MOS‐supplemented group. Histological observations of post‐fed animals revealed that MOS supplementation resulted in increased absorptive surface area of the intestine and increased glycogen deposition in liver. The result of this experiment infers that MOS supplementation has got a beneficial effect in the diet of seabass and supplementation at 1% level is optimal for improving the growth.     

Effects of dietary macronutrient level and feeding frequency on growth and body composition of juvenile rockfish (Sebastes schlegeli)

An 8-week feeding experiment was conducted to investigate the effects of different dietary macronutrient level and feeding frequency on the growth, feed utilization, and body composition of juvenile rockfish. Triplicate groups of fish (body weight of 4.1 g) were fed the experimental diets containing either high levels of carbohydrate (HC, 35%), lipid (HL, 13%), or protein (HP, 55%) at different feeding frequencies (twice daily, once daily, and once every 2 days). Weight gain was affected by feeding frequency but not by dietary composition. Weight gain of fish fed the diets once every 2 days was significantly (P < 0.05) lower than that of other groups. Daily feed intake and energy intake were affected by both dietary composition and feeding frequency. Daily feed intake of fish fed the HC diet was significantly (P < 0.05) higher than that of fish fed the HL and HP diets at the same feeding frequency. Feed efficiency and protein efficiency ratio were affected by both dietary composition and feeding frequency and decreased with increasing feeding frequency in the same dietary composition. Feed efficiency and protein efficiency ratio of fish fed the HC diet were significantly (P < 0.05) lower than those of fish fed the HL diet at the same feeding frequency. Whole-body lipid content of fish fed the HL diet was significantly (P < 0.05) higher than that of fish fed the HC and HP diets at the same feeding frequency. These results indicate that an increase of dietary lipid level compared with dietary carbohydrate level may have the advantage of a protein-sparing effect at same feeding frequency, and a once-daily feeding regime is more effective than twice daily or one feeding every 2 days to improve growth performance of juvenile rockfish grown from 4 to 21 g.     

Effect of feeding frequency on growth,feed utilization,body composition and waste output of juvenile golden pompano (Trachinotus ovatus) reared in net pens

A 6‐week feeding trial was conducted to examine the effect of feeding frequency on growth, feed utilization efficiency, body composition and waste output of juvenile golden pompano Trachinotus ovatus reared in net pens. Fish (10.3 ± 0.5 g) were either fed a formulated diet containing 48.4% crude protein and 5.7% crude lipid at 0.5, 1, 2, 3 or 4 meals per day or fed a raw fish feed at two meals per day as a control. The weight gain (WG) increased with increasing feeding frequency from 0.5 to 3 meals per day (P < 0.05), but did not significantly change with the further increase in feeding frequency from 3 to 4 meals per day (P > 0.05). The feed intake (FI) was lower in fish fed at 0.5 or 1 meal per day than in fish fed at 2, 3 or 4 meals per day (P < 0.05). No significant differences were found in the feed conversion ratio (FCR), nitrogen retention efficiency (NRE), condition factor (CF), nitrogen waste output (NWO) and phosphorus waste output (PWO) between fish fed at 1, 2, 3 or 4 meals per day (P > 0.05), whereas no significant difference was found in the phosphorus retention efficiency (PRE) among the feeding treatments (P > 0.05). The body lipid content increased, whereas the contents of moisture and ash decreased, with the increase in feeding frequency (P < 0.05). At the same feeding frequency, fish fed the formulated diet exhibited lower FI, FCR, HSI, body moisture content, NWO and PWO, but higher NRE, PRE, body lipid content and body phosphorus content than those of fish fed the raw fish feed (P < 0.05). These results suggest that the formulated diet can satisfy nutrient requirements of juvenile golden pompano reared in net pens, and the suitable feeding frequency is 3 meals per day.     

低鱼粉饲料中添加牛磺酸对青鱼幼鱼生长、肠道修复及抗急性拥挤胁迫的影响

为研究低鱼粉饲料中添加牛磺酸对青鱼幼鱼[初始质量(5.90±0.03)g]生长、肠道修复及抗急性拥挤胁迫的影响,实验以青鱼正常鱼粉组(20%)为对照组,10%鱼粉组为负对照组(I_0组),在低鱼粉饲料中分别添加0.05%(I_(0.05)组)、0.1%(I_(0.1)组)、0.2%(I_(0.2)组)、0.4%(I_(0.4)组)牛磺酸,配制6种等氮等脂饲料,饲养8周。饲养实验结束后,参考生长结果,选择对照组、I_0组、I_(0.1)组、I_(0.4)组进行急性拥挤胁迫实验。结果显示:①与对照组相比,I_0组增重率显著下降,随着低鱼粉饲料中牛磺酸水平的升高,青鱼幼鱼增重率呈先上升后下降趋势,当牛磺酸添加量为0.1%时与对照组差异不显著;②相对于对照组,I_0组的绒毛高度降低、隐窝深度增加,杯状细胞数降低,添加牛磺酸使绒毛高度升高、隐窝深度降低,杯状细胞数和淋巴细胞数增多;③急性拥挤胁迫使青鱼幼鱼血清史质醇、血糖、血清溶菌酶(LSZ)、补体C3、超氧物歧化酶(SOD)和谷胱甘肽(GSH)含量均呈先升高后下降的趋势,其最大值出现在胁迫2 h或者8 h。在整个胁迫期间,I_0组史质醇和血糖含量高于其他各饲料组,I_0组溶菌酶、补体C3、SOD和GSH均低于其他各饲料组。研究表明,在低鱼粉饲料中添加牛磺酸可提高青鱼生长性能、改善肠道结构、增强青鱼的抗急性拥挤胁迫的能力。     

Effects of body weight on the growth and physiology of Salmo salar L. during smoltification

To study the effects of body weight on growth and physiological response mechanism of S. salar, fish of three average body weights were selected: 30.25 ± 2.12 g (SW1), 24.27 ± 1.59 g (SW2) and 18.05 ± 2.46 g (SW3). Condition factor, daily weight gain and feed conversion efficiency were significantly higher in the SW2 group compared with the other treatment groups (P < 0.05). Food conversion ratio decreased with increasing body weight, and weight and specific growth rate of body length were highest in the SW2 group (P < 0.05). Larger fish (SW1 and SW2) had higher haemoglobin concentration and number of red blood cells. The number of white blood cells, lymphocytes and neutrophils were greatest in the SW3 group (P < 0.05), suggesting that these fish had strong resistance to disease. The content of total protein, albumin and urea were significantly higher in the SW2 group compared with other groups (P < 0.05). The concentration of total cholesterol and triglyceride increased with increasing body size (P < 0.05). Hormone (T3 and T4) levels first increased significantly and then decreased in fish of various sizes (P < 0.05), and the concentration of cortisol rose, fell and then rose again in SW1 and SW2 groups. Light affected the endocrine activity of S. salar by influencing the growth performance of the fish, and smaller sized fish exhibited decreased smoltification rate and a reduced success rate of smoltification. Based on these findings, S. salar weighing about 24 g were chosen to begin the process of smoltification.     

Role of taurine deficiency in inducing green liver symptom and effect of dietary taurine supplementation in improving growth in juvenile red sea bream <Emphasis Type="Italic">Pagrus major</Emphasis> fed non-fishmeal diets based on soy protein concentrate

This study was conducted to investigate the mechanism of green liver symptom induction and the effect of dietary taurine supplementation on growth performance in juvenile red sea bream fed non-fishmeal diets based on soy protein concentrate (SPC). Juvenile fish (initial BW 72 g) were fed for 20 weeks on SPC diets supplemented with taurine at levels of 0, 1.0, and 2.0%. In the taurine-unsupplemented SPC diet group, specific growth rate (SGR) and feed conversion ratio (FCR) were significantly inferior (P < 0.001), and incidence of green liver was observed in 70% of fish. In this group, hepatopancreatic and plasma taurine concentrations were lowest (P < 0.05), hepatopancreatic content of bile pigments was highest (P < 0.05), and osmotic tolerance of erythrocytes was inferior (P < 0.05) among the dietary treatment groups. Serum osmolality of all treatment groups was at similar levels. These physiological abnormalities as well as SGR and FCR were improved by dietary taurine supplementation. These results indicate that the mechanism for induction of green liver symptom is bile pigment overproduction due to increased hemolysis because erythrocytes become osmotically fragile due to dietary taurine deficiency. Taurine supplementation of SPC diets is essential for maintaining normal physiological condition and growth performance in juvenile red sea bream.     

The effect of spray‐dried porcine plasma on gilthead seabream (Sparus aurata) intestinal microbiota

The effect of spray‐dried porcine plasma (SDPP) on the intestinal histological organization and autochthonous microbiota composition was evaluated in Sparus aurata. Fish were fed a basal diet (51 g/kg protein, 17 g/kg fat, 20.6 MJ/kg gross energy) and a diet containing 3 g/kg SDPP for 95 days (initial body weight, BW = 9.5 ± 0.2g, mean ± SD). The inclusion of SDPP promoted growth (p < .05), being fish fed the SDPP diet 6.2% (BW = 88.2 ± 1.6 g) heavier than the control (BW = 82.7 ± 3.2 g). SDPP increased the density of intestinal goblet cells (p < .05), whereas no differences in villi height were found (p > .05) between both groups. Intestinal microbiota was dominated by Proteobacteria (>85%) and Firmicutes (5%–12%), whereas Bacteroidetes never represented more than 1.5%. γ‐Proteobacteria, and Bacilli and Clostridia were the predominant classes. The short administration of SDPP (20 days) resulted in changes in microbiota diversity and richness associated with an increase in the sequences of the genus Lactobacillus and to a decrease in the genus Vibrio, whereas these changes were reverted at 95 days. Intestinal goblet cell density was not correlated to microbiota diversity and richness changes rather than to the immunostimulatory effect of the SDPP.     

Histochemical distribution of intestinal enzymes of juvenile pacu (Piaractus mesopotamicus) fed lyophilized bovine colostrum

Enzyme activity was evaluated in the intestine of juvenile pacu, Piaractus mesopotamicus, fed diets containing 0, 10 or 20 % of lyophilized bovine colostrum (LBC) inclusion for either 30 or 60 days. The enzymes intestinal acid and alkaline phosphatase (ACP and ALP, respectively), nonspecific esterase (NSE), lipase (LIP), dipeptidyl aminopeptidase IV (DAP IV) and leucine aminopeptidase (LAP) were studied using histochemistry in four intestinal segments (S1, S2, S3 and rectum). Moderate activity of the DAP IV was detected in the three last intestinal segments, but no differences among the treatments were detected. Enzymes LAP, NSE and LIP were weakly stained in all intestinal segments and the inclusion of 10 or 20 % of LBC in the diet commanded a moderate reaction to NSE in the S3 segment at day 60. ACP activity was detected only in the brush border of the S1 segment of fish fed 0 % LBC for either 30 or 60 days. The activity of ALP was very strong in the first intestinal segment, but a weak reaction was seen in the last segments. The inclusion of 20 % of LBC changed the pattern of staining to the ALP, eliciting moderate staining in S2 at day 30 and S1 at day 60. The consumption of diets containing LBC by juvenile pacu did not have significant implications in intestinal enzymatic activity, which still was not fully stimulated.     

Requirements for n-3 highly unsaturated fatty acids in feeding juvenile Iranian sturgeon (<Emphasis Type="Italic">Acipenser persicus</Emphasis>) and its effects on growth,carcass quality,and fatty acid composition

A 60-day feeding experiment was carried out on juvenile Iranian sturgeon (Acipenser persicus) to evaluate the effects of different percentages of canola oil and fish oil containing n-3 highly unsaturated fatty acids (n-3 HUFA) on fish growth and fatty acid composition. The requirement for n-3 HUFA of juvenile Iranian sturgeon (48.4 ± 1.98 g) was studied by feeding the fish with various diets containing six different percentage of n-3 HUFA ranging from 1.56 to 17.25 (% of total fatty acids). Neither the weight gain, feed conversion ratio, condition factor, specific growth rate nor the protein efficiency ratio showed any significant differences between the dietary treatments nor in the body composition of juvenile Iranian sturgeon (P > 0.05); also there were no significant difference with respect to the effect of the dietary treatment (P > 0.05) on the blood parameters, for the content of plasma protein, glucose, cholesterol, and triglyceride. The fatty acid composition of the carcass of the Iranian sturgeon fed with the diets containing various levels of n-3 HUFA was reflected by the dietary fatty acid composition. The content of n-3 HUFA in the fish increased with an increase in dietary n-3 HUFA levels. The results indicate that the dietary n-3 HUFA had no effect on the growth of juvenile Iranian sturgeon.     

Studies on quantitative trait loci related to superoxide dismutase in mirror carp (Cyprinus carpio L.)

The F1 progeny from parents selected randomly for differences in performance traits from different families of mirror carp were used as a mapping panel. Linkage maps constructed using Join Map 4.0 software with 992 microsatellite polymorphic markers ultimately yielded 51 groups. Composite interval mapping (CIM) of superoxide dismutase (SOD) trait of three tissues (liver, anterior and posterior intestine) was conducted for quantitative trait loci (QTL) location using Map QTL 6.0 software. Results shows that seven QTLs significantly (P < 0.05) explained 8.2–18.5% of the phenotypic variations in liver, five QTLs explained 7.9–11.1% of the variation in anterior intestine (P < 0.05) and six QTLs were located and explained 6.1–15.8% of the phenotypic variations in posterior intestine (P < 0.05). NCBI BLASTn was used for homology analysis between the sequences from markers used in the located QTL regions and sequences from the zebrafish database, and many protein relating with the SOD expression were blasted (similarity >85%). These results showed that it is highly probable that these QTLs are the main regions of SOD expression. The data also support the value of forward genetic studies on organism development and serve as a basis for selection.