Zinc supplementation of practical channel catfish diets

A 10-week feeding trial was conducted with fingerling channel catfish (Ictalurus punctatus to determine the supplemental zinc level needed in a practical catfish diet. As phytic acid has been demonstrated to reduce zinc bioavailability, diets in this study were formulated to contain a relatively high level of phytic acid as compared to most commercial catfish diets. Incremental levels of zinc (as ZnO) were added to a soybean meal-based diet which contained 54 mg Zn/kg dry diet and 1.1% phytic acid. Catfish growth and feed efficiency were not improved with zinc supplementation. Serum zinc concentration did not increase significantly above a supplemental zinc level of 100 mg Zn/kg diet; whereas, bone zinc concentration plateaued at the 150 mg/kg supplemental zinc level and above. Based on these data a supplemental zinc level of 150 mg Zn/kg diet is recommended for practical catfish feeds to provide enough available zinc to the channel catfish.     

Effects of inorganic and organic dietary copper supplementation on growth performance and tissue composition for juvenile red drum (Sciaenops ocellatus L.)

A feeding trial was conducted to evaluate the dietary copper requirement of red drum (Sciaenops ocellatus) and compare the bioavailability of copper sulphate (CuSO₄) and copper‐ethanolamine. A basal diet was formulated using semi‐purified ingredients and analysed to contain 3 mg Cu/kg. Both copper sources were supplemented to the basal diet at either 5, 10 or 20 mg Cu/kg of dry diet. No significant differences were observed in growth performance of fish fed the various diets. However, red drum fed all copper‐supplemented diets retained more copper in liver and whole‐body tissues compared to fish fed the basal diet. Within both inorganic and organic copper treatments, the highest tissue copper concentrations were observed in fish fed diets supplemented with 10 mg Cu/kg. No significant differences were detected in net copper retention regardless of the nature of the copper source; hence, the bioavailability of copper sulphate and copper‐ethanolamine complex was not different in the diets for juvenile red drum. Furthermore, the minimum copper requirement for growth performance of juvenile red drum appeared to be satisfied when fish were fed the basal diet containing 3 mg Cu/kg diet, and no detrimental effects were observed in red drum fed diets supplemented with 20 mg Cu/kg.     

Evaluation of the Dietary Zinc Requirement of Penaeus vannamei and Effects of Phytic Acid on Zinc and Phosphorus Bioavailability

Experiments were conducted to determine the dietary zinc requirement of Penaeus vannomri and evaluate the effects of phytate on zinc bioavailability. Prior to initiation of the growth trial, 20-day-old P. vonnamei postlarvae (mean weight 0.0032 g) were fed a casein-gelatin based semi-purified diet lacking zinc supplementation but containing 18 mg Zn/kg diet for one week. Subsequently, juveniles (mean weight 0.058 g) were fed one of seven diets containing either supplemental zinc (0, 15, 30, 60 mg/kg diet) without phytate or supplemental zinc (0, 60, 200 mg/kg diet) with 1.5% phytate for 33 days. Weight gain was greatest in shrimp fed 15 mg supplemental Zn/kg diet. In the absence of dietary phytate, zinc concentrations in the hepatopancreas of shrimp were maximized when zinc was supplemented at levels greater than or equal to 15 mg Zn/kg diet (33 mg total Zn/ kg). Supplementation of 1.5% phytate to the diet did not have a significant effect on growth or zinc concentrations in the carapace; however, it did depress zinc levels in the hepatopancreas. Supplementation of 200 mg Zn/kg diet was required to overcome the depressed bioavailability of zinc caused by the presence of dietary phytate and return zinc levels of the hepatopancreas to that observed when phytate was not present. Based on apparent digestibility values phytate phosphorus was unavailable to the shrimp and the presence of phytate depressed the bioavailability of phosphorus and zinc.     

The fate of chlortetracycline residues in a simulated chicken–fish integrated farming systems

Two experiments were conducted at the Asian Institute of Technology, Pathumthani, Thailand to investigate the fate of chlortetracycline (CTC) residue in chicken manure and its effect on integrated chicken–fish farming system. During the first experiment, broiler chickens were raised and CTC residues in their manure were analysed. Chicken fed diets containing 0, 50, 200 and 800 CTC mg kg^?1 had CTC residue levels of 0, 0.9, 3.8 and 6.5 CTC ng g^?1. Once the diet containing CTC was withdrawn, CTC in the manure dropped to negligible amounts (0, 0, 0.2 and 0.5 CTC ng g^?1) within 1 day. Integrated chicken–fish farming systems were simulated during the second experiment to determine the fate of antibiotic residues in chicken manure in aquaculture environment. Chickens were fed a CTC‐free diet and a feed containing CTC at 200 mg kg^?1. Ten 4 m³ square concrete tanks (2 × 2 × 1 m) were used for the experiment. Five tanks were fertilized with CTC‐contaminated manure and the remaining five tanks were fertilized with CTC‐free manure at a rate of 100 kg dry matter ha^?1 day^?1. Sex‐reversed Nile tilapia (Oreochromis niloticus) was stocked at 12 fish tank^?1 on the 14th day after chicken manure application. The immuno‐radio microbial receptor assay (Charm II test) revealed that edible fish muscle, fish intestinal tract and sediment were contaminated by CTC at rates of 7.21, 22.104 and 1.788 ng g^?1, respectively, after 45 days. Chlortetracycline was detected on day 20 in the water column and gradually increased from 0.26 to 12.13 ng g^?1. Chlortetracycline residues were not detected in fish or the aquatic environment of the CTC‐free treatment. The results demonstrate the potential for antibiotic residue accumulation in fish and aquatic environment when CTC‐contaminated chicken manure is used for pond fertilization.     

Sex reversal and growth of Oreochromis spilurus (Günther) in brackish and sea water by feeding 17α-methyltestosterone

Abstract. An investigation was undertaken to study the effect of 17α-methyiteslosterone (17-MT) on the sex reversal and growth of tilapia, Oreochromis spilurus (Günther), in brackish water (3–5 ppt) and sea water (40 ppt). Seven experiments were performed; four in brackish water and three in sea water. Yolk-sac fry (1 or 3 day age) were immersed (7 or 24 h/day) in water containing hormone at a concentration of 0–10mg/l for 4–25 days. The swim-up fry were subsequently fed either normal or hormone-impregnated diets (30–70 mg/kg) for another 35 days starting from first feeding. The growth and SGR of fry were better in groups which received hormone both in water and food as compared with water or food alone. Immersion In 5–10 ppm (24 h/day) brackish water solution for 5 days did not bring any change in growth or sex ratio. However, immersion in sea water solution for 25 days (7 h/day) at a concentration of 1 ppm induced positive growth but no change in sex ratio. Higher doses either did not affect or reduced growth and SGR but induced higher percentages (77–83%) of males. Complete masculinization (100%) was observed only in brackish water when fish were immersed in 2·5 ppm solution for 4 days (24 h/day) and later fed 50 mg/kg in diets for 35 days. These results were further confirmed when the immersion schedule was modified to 10 days (7 h/day) and feeding 50–70 mg/kg hormone. It can be concluded from these studies that in brackish water complete masculinization of O. spilurus is possible through immersion in 5·0 ppm for a minimum of 75 h followed by feeding with 50 mg/kg food for a minimum of 40 days starting from first feeding.     

Minimum requirement of vitamin E for Atlantic salmon, Salmo salar L., at first feeding

The minimum requirement of vitamin E for Atlantic salmon, Salmo salar L., at first feeding was found to be 60 mg dl-α-tocopheryl acetate per kg dry diet. The dry diet contained 5.6% polyunsaturated fatty acids, which is similar to that used in practical diets at first feeding. Preliminary results indicate that the optimal dietary vitamin E level is 120 mg dl-α-tocopheryl acetate per kg dry diet, or more. Further research is necessary to confirm this hypothesis.     

Myopathies in a riding horse stable

In this case report on myopathies in 6 saddle-horses, a combined dietary vitamin E and selenium deficiency is presumed. Other disorders, such as exertional myopathy ("Monday morning disease") due to excessive energy intake or ionophore intoxication could be excluded by calculating the energy supply or by a simple colour test. The selenium requirement of horses is estimated to 0.1-0.2 mg/kg dry matter (Meyer 1986). If natural feed compounds are low in selenium, adequate amounts of this trace element can be supplied by means of supplemental feeds, sodium selenite (20 mg/500 kg BW/week) or bruised linseed (cooked, 200-500 g/d). In horses tolerance of increased selenium intake is low. After oral administration of sodium selenite lethal dose was 3.3 mg/kg bodyweight. In feedstuffs selenium concentration must be below 5 mg/kg dry matter (Traub-Dargatz et al, 1986). The intake of vitamin E should be 0.25-1 mg/kg bodyweight. The requirements are influenced by feed compounds, especially the concentration of dietary unsaturated fatty acids, and the performance of the horses (Meyer 1986). Foals, pregnant or lactating mares, and racing horses have higher requirements. In acute disease vitamin E and selenium are given parenterally (5 mg Se/horse) or by oral application of sodium selenite (46% selenium, 20 mg/horse), in addition to symptomatical treatment.     

Dietary Zinc Requirement of Oreochromis aureus and Effects of Dietary Calcium and Phytate on Zinc Bioavailability

Two experiments were conducted to determine the dietary zinc requirement of fingerling blue tilapia ( Oreochromis oureus ) and the effects of dietary calcium and phytate on zinc bioavailability. Purified egg white diets containing graded levels of supplemental zinc were fed to fingerling tilapia in triplicate aquaria for 80 days. No overt signs of zinc deficiency were observed; however, scale and bone zinc concentrations of fish fed the various diets were significantly (P < 0.05) affected and increased linearly as dietary zinc increased until plateauing at 20 mg Zn/kg diet and greater. Based on these data, 20 mg Zn/kg of dry diet was determined to be the minimum dietary zinc requirement of blue tilapia. Purified egg white diets containing 20 mg Zn/kg were also supplemented with 0.5 or 2.0% calcium and 0 or 1.5% phytate in a factorial arrangement to determine the effects of these dietary factors on zinc bioavailability. At this level of supplemental zinc, 1.5% phytate significantly ( P < 0.05) reduced zinc bioavailability as reflected in scale and bone zinc concentrations; whereas, dietary calcium did not affect zinc bioavailability. Results from this study establish the dietary zinc requirement of blue tilapia and indicate that higher levels of supplemental zinc should be included in practical feeds to compensate for reduced zinc bioavailability caused by dietary phytate.     

Dietary Zinc Requirement of Oreochromis aureus and Effects of Dietary Calcium and Phytate on Zinc Bioavailability

Two experiments were conducted to determine the dietary zinc requirement of fingerling blue tilapia ( Oreochromis aureus ) and the effects of dietary calcium and phytate on zinc bioavailability. Purified egg white diets containing graded levels of supplemental zinc were fed to fingerling tilapia in triplicate aquaria for 80 days. No overt signs of zinc deficiency were observed; however, scale and bone zinc concentrations of fish fed the various diets were significantly ( P < 0.05) affected and increased linearly as dietary zinc increased until plateauing at 20 mg Zn/kg diet and greater. Based on these data, 20 mg Zn/kg of dry diet was determined to be the minimum dietary zinc requirement of blue tilapia. Purified egg white diets containing 20 mg Zn/kg were also supplemented with 0.5 or 2.0% calcium and 0 or 1.5% phytate in a factorial arrangement to determine the effects of these dietary factors on zinc bioavailability. At this level of supplemental zinc, 1.5% phytate significantly ( P < 0.05) reduced zinc bioavailability as reflected in scale and bone zinc concentrations; whereas, dietary calcium did not affect zinc bioavailability. Results from this study establish the dietary zinc requirement of blue tilapia and indicate that higher levels of supplemental zinc should be included in practical feeds to compensate for reduced zinc bioavailability caused by dietary phytate.     

饲料中添加维生素E对畜禽肉质的影响

为研究虎龙杂交斑对维生素E(V_E)的最适需求量,评估V_E对虎龙杂交斑生长性能、抗氧化和免疫功能的影响,实验设计了6组V_E 含量分别为4.1、26.3、40.7、57.1、116.8、209.6 mg/kg的等能(340 kcal/100 g干物质)、等蛋白(占饲料干重的51.5%)、等脂(占饲料干重的9%)的实验饲料,每组3个平行。实验鱼初始均重为(14.22±0.01) g,养殖实验期间每日饱食投喂2次(8:00和16:30),周期为8周。生长实验结束后每组随机挑选7尾实验鱼进行72 h铜胁迫实验。实验结果显示,摄食57.1 mg/kg V_E饲料实验鱼增重率(WG)显著高于摄食4.1 mg/kg V_E饲料实验鱼,各实验组肥满度(CF)、肝体比(HSI)和肠系膜脂肪比(IPF)无显著差异。全鱼和肌肉水分、粗蛋白和粗脂肪含量在各V_E处理组之间也无显著差异。摄食209.6 mg/kg V_E饲料实验鱼肝脏V_E含量高于摄食4.1 mg/kg V_E饲料实验鱼。肝脏总抗氧化能力(T-AOC)、血清溶菌酶(LZM)活性和免疫球蛋白(IgM) 活性均先升后降, 4.1 mg/kg V_E组以上指标均低于57.1 mg/kg V_E组。铜胁迫72 h后,40.7、57.1和116.8 mg/kg V_E组存活率均显著高于4.1 mg/kg V_E组。40.7 mg/kg V_E组头肾核因子E2相关因子2 基因 (nrf2)的相对表达量高于4.1、26.3和116.8 mg/kg V_E组。以WG和T-AOC为评价指标,基于二次折线模型确定虎龙杂交斑饲料中V_E的最适需求量分别为62.92 mg/kg饲料和86.25 mg/kg饲料。实验结果表明,饲料中添加适量的V_E可提高虎龙杂交斑生长性能、抗氧化和免疫能力。

     

Recent Advances in Nutrition of Penaeus monodon

This paper provides a brief summary of information on recent advances in the nutrition of Penaeus monodon . The nutritional requirements of P. monodon have been little known despite its importance in aquaculture. Recent findings indicate a noticeable difference between some important nutrient requirements of P. monodon and P. japonicus , the most studied shrimp species. For example, the thiamin requirement for P. monodon was estimated to be 14 mg/kg diet, while for P. japonicus it is 60-120 mg/kg diet for juveniles and 40-80 mg/kg diet for larvae. The same contrast was also observed in the requirements of riboflavin (22.5 mg/kg in juvenile P. monodon vs. 80 mg/kg in larval P. japonicus ), niacin (6.4 mg/kg vs. 400 mg/kg) and vitamin C (2,000-2,500 mg/kg vs. 10,000 mg/kg).
Research efforts to understand the lack of ability for shrimp to effectively use dietary crystalline amino acids have resulted in the development of a microencapsulated amino acid that can be assimilated by P. monodon which is incapable of utilizing the essential amino acid in crystalline form. This development enables the quantification of requirements of the amino acid and other essential amino acids for shrimp. A study using cellulose-acetate-phthalate encapsulated arginine indicated that the arginine requirement of postlarval P. monodon is 5.47 g/100 g protein (2.50 g/100 g diet).
Other aspects concerning the importance of digestive enzymes, dietary requirements of protein, carbohydrate, lipid and vitamin, energy and larval feeding for P. monodon were reviewed.     

The minimum dietary requirement of vitamin C in Atlantic salmon (Salmo salar) fry using Ca ascorbate-2-monophosphate as dietary source

The minimum dietary vitamin C requirement for optimal growth and normal development in Atlantic salmon (Salmo salar) fry at the onset of feeding was studied, using Ca ascorbate-2-monophosphate (AP) as dietary source. The requirement was established by means of a feeding study lasting for 23 weeks from the beginning of feeding. The practical diets used were supplemented with AP at levels of 0, 10, 20, 40, 80 and 160 mg ascorbic acid (AA) equivalents/kg. Growth, mortality, hydroxyproline content in skin and backbone, and AA in liver were recorded to evaluate the results. The results suggest that the minimum dietary requirement for optimal growth and normal development is in the range of 10–20 mg AA equivalents/kg dry diet during the period studied.     

Dietary Zinc Requirement of Hybrid Striped Bass,Morone chrysops×Morone saxatilis,and Bioavailability of Two Chemically Different Zinc Compounds

Zinc is a trace mineral element that plays an essential role in numerous biochemical processes, and has been shown to affect growth and health of several fish species. However, the dietary zinc requirement of hybrid striped bass has not been defined. Therefore, a feeding trial was conducted to determine the dietary requirement for zinc by this fish and to compare zinc bioavailability of two chemically different forms (zinc sulfate and zinc proteinate). Six experimental diets were formulated with purified ingredients and supplemented with ZnSO₄ to provide total zinc concentrations of 7, 12, 16, 26, 42, and 80 mg/kg diet which were determined by analysis. Each diet contained 32% crude protein, 6% lipid, and approximately 14.2 kJ of digestible energy per gram. The experimental diets were fed twice daily for 10 wk to triplicate groups of 15 hybrid striped bass initially weighing 0.86 ± 0.05 g/fish in 38‐L glass aquaria, connected as a recirculating system. Finally, after the feeding period, the fish were evaluated for weight gain, feed efficiency, protein efficiency ratio, and survival, as well as blood serum zinc, bone zinc, and hematocrit. All fish thrived during the feeding trial and not even the fish fed the basal diet displayed any apparent deficiency signs, although weight gain steadily increased with escalating levels of dietary zinc up to 42 mg/kg diet. On the basis of the most responsive indicators–bone zinc and serum zinc–the minimum dietary zinc requirement of hybrid striped bass was determined to be 17.0 and 17.3 mg Zn/kg diet, respectively, based on broken‐line regression. This estimate is similar in magnitude to dietary zinc requirements reported for other fish species. In addition, the bioavailability of zinc proteinate versus that of ZnSO₄ was estimated by deriving the ratio of the slopes of the regression lines fitted to bone zinc and serum zinc data. This analysis indicated that hybrid striped bass utilized zinc proteinate ～1.7 times more efficiently than ZnSO₄.     

Effects of Fungal Phytase on Utilization of Dietary Protein and Minerals, and Dephosphorylation of Phytic Acid in the Alimentary Tract of Channel Catfish Ictalurus punctatus Fed an All-Plant-Protein Diet

A feeding trial was conducted to quantify the effects of phytase at levels of 0, 500, 1,000, 2,000, 4,000, and 8,000 units (U) per kg diet on utilization of dietary protein and minerals by fingerling (12 g) channel catfish Ictalurus punctatus fed an all‐plant‐protein diet composed of soybean meal, corn, and wheat middlings. The effects of phytase on dephosphorylation of phytic acid (phytate) in the alimentary tract of catfish also were determined. After 14 wk, mean weight gains (30.2–43.9 g/fish), feed conversion ratios (2.27–2.40 g feed consumed/g weight gain), protein efficiency ratios (1.47–1.61 g weight gaid/g protein consumed), and dietary protein retentions (23.8–26.7%) did not differ significantly (P > 0.05) among treatment groups. A digestibility trial conducted after the feeding trial showed no difference (P > 0.05) in mean digestibility of diet dry matter (49.0–58.3%) or crude protein (85.4‐88.5%) among treatment groups. Concentrations of ash (46.7–48.6%), calcium (Ca, 17.9–18.5%), phosphorus (P, 9.1–9.5%), and manganese (Mn, 65.5–74.1 mg/kg) were significantly higher (P ≤ 0.05) in bone of fish fed ≥ 500 U/kg than in bone of fish fed 0 U/kg (ash, 43.5%; Ca, 16.4%; P, 8.4%; and Mn, 49.0 ma/kg), but concentrations of these minerals did not differ (P > 0.05) in bone of fish fed ≥ 500 Uk/g. The magnesium (Mg) content of bone did not differ (P > 0.05) between fish fed 0 U/kg (0.29%) or 500 U/kg (0.34%), but was significantly lower in fish fed 0 U/kg than in fish fed ≥ 1,000 U/kg (0.35–37%). Bone Mg levels did not differ (P > 0.05) among fish fed ≥ 500 U/kg. The amount of zinc (Zn) in bone of fish fed 8,000 U/kg (153.3 mg/kg) was significantly higher than that in fish fed 0 U/kg (115.7 mg/kg) or 500 U/kg (130.3 mg/ kg), but did not differ from Zn levels in bone of fish fed 1,000–4,000 U/kg (134.5–135.8 mg/ kg). Dephosphorylation of phytate occurred primarily in the stomach within 2–8 h after diet ingestion, depending on the level of phytase supplementation. Initial levels of total phytate in the diet decreased 32–94% in stomach contents of fish fed l,000–8,000 U/kg within 2 h after feeding. Eight hours after feeding, stomach contents of fish fed ≥ 1,000 U/kg contained less than 6% of initial total dietary phytate. Stomach contents of fish fed 500 U/kg retained 92% of initial total dietary phytate 2 h after feeding and 15% of total dietary phytate 8 h after feeding. Results of this study indicate that phytase supplementation at levels up to 8,000 U/kg diet did not increase weight gain or improve dietary protein utilization of channel catfish fed an all‐plant‐protein diet. Addition of phytase at a level of 1,000 U/kg diet was sufficient to significantly increase the Ca, P, Mg, and Mn content of bone, relative to fish fed an unsupplemented diet, and significantly decrease the quantity of total phytate in feces. A phytase level of 8,000 U/kg diet significantly increased the bioavailability of naturally occurring Zn in feed ingredients and increased the rate of phytate dephosphorylation in the stomach, compared with a diet containing no added phytase. Increased utilization of naturally occurring minerals in feed ingredients reduces the need for mineral supplements in diets and results in decreased elimination of minerals in feces. Thus, use of phytase in catfish feeds can be expected to provide both economic and environmental benefits.     

Periodical changes of plasma free amino acid levels and feed digesta in yellowtail after feeding non-fishmeal diets with or without supplemental crystalline amino acids

ABSTRACT: Postprandial changes of free amino acid (FAA) concentrations in plasma and feed digesta contents were examined in yellowtail, Seriola quinqueradiata (220–280 g bodyweight) fed non-fishmeal diets either with or without supplemental crystalline amino acids (lysine, methionine, threonine, and tryptophan) in order to evaluate the availability of supplemental amino acids. Non-fishmeal diets containing 30% soy protein concentrate as the major protein source were prepared in three diet forms: soft dry pellet, extruded pellet, and single moist pellet. The level of plasma FAA and feed digesta content were determined at 0, 3, 6, 9, 12, 18, and 24 h after feeding. Plasma levels of four supplemental amino acids in fish fed the non-fishmeal diets with EAA were higher than those of fish fed diets without EAA, suggesting that yellowtail can efficiently absorb supplemental crystalline amino acids irrespective of diet form. However, a remarkable difference was observed in the periodical patterns of these four amino acids between FAA derived from supplements and those from feed protein. Moreover, FAA patterns in fish fed the non-fishmeal diets with EAA were different from those of the control fishmeal diet. Of note, methionine concentration was markedly high during the whole experimental period, resulting in an amino acid imbalance that may have caused lower feed performances in fish fed the non-fishmeal diets with EAA compared to the control fishmeal diet.     

日粮铁对草鱼生长、营养成分和部分血液指标的影响

选用(7.12±0.22)g的草鱼(Cenopharyngodon idellus)鱼种,分别在纯化日粮中添加铁0,100,200,300,400,500 mg/kg,进行为期78 d的生长试验以考察铁对草鱼生长性能、营养成分和部分血液指标的影响。试验结果显示,日粮中添加铁对草鱼的生长、体成分和血红蛋白和红血细胞数目等都有显著影响。日粮中添加铁300 mg/kg时,草鱼增重率、特定生长率、饲料效率、蛋白质效率比、蛋白沉积效率达最大值;体蛋白和肌肉蛋白含量高,脂肪含量低,灰分含量高;血红蛋白和红血细胞均达最高水平。结果说明:草鱼纯化日粮中铁的适宜添加量为300 mg/kg。     

Effects of dietary supplementation of A3α-peptidoglycan on innate immune responses and defense activity of Japanese flounder (Paralichthys olivaceus)

To determine the effect of dietary supplementation of A3α-peptidoglycan (A3α-PG), extracted from Bifidobacterium sp. cell wall, on the immune responses of Japanese flounder (Paralichthys olivaceus) and explore a possible influence of doses and administration length, a 40-day feeding trial was conducted to evaluate graded levels (0, 0.5, 1, 2, 4, 8 and 16 g A3α-PG/kg diet) in the diet of juvenile Japanese flounder, followed by a challenge with Vibrio anguillarum by intraperitoneal injection. Growth, serum lysozyme, hemolytic complement activity, blood leucocyte phagocytic activity, respiratory burst, and total serum protein were monitored at intervals of 10, 20, 30 and 40 days.Growth, serum lysozyme, hemolytic complement activity, blood leucocyte phagocytic activity of juvenile Japanese flounder were generally enhanced by dietary supplementation of 1, 2, 4 and 8 g A3α-PG/kg diet and also enhanced immune responses, but not growth. The beneficial influence of A3α-PG on most of the tested immune responses were dose- and/or administration length-dependent except serum lysozyme, which was only stimulated by higher doses (more than 2 g A3α-PG/kg) after 40 days feeding. No significant influence of dietary supplementation of 0.5 g A3α-PG/kg on innate immunity was observed on juvenile fish. The highest dose explored in the present study, 16 g A3α-PG/kg, also failed to show any significant influences, although no obvious pathology was observed. Dietary supplementation of A3α-PG showed protection against V. anguillarum. The present study showed an immunomodulatory effect of dietary supplementation of A3α-PG and the potential use in health management of cultured economic fish species such as Japanese flounder.     

Decreased transport of orally administered protein into the blood circulation of developing juveniles of Japanese eel Anguilla japonica

ABSTRACT: To clarify the quantitative changes in the transport of orally intubated protein into the blood circulation as macromolecules in development, immunoglobulin Y (IgY) extracted from chicken eggs was administered orally to juvenile Japanese eel, Anguilla japonica . For the first experiment, which was performed before the commencement of artificial feeding, the oral delivery of 2.0 μg/0.1 g bodyweight of IgY resulted in a rapid increase in plasma IgY to a maximum of 2.30 μg/mL. However, the transport of IgY into the blood decreased significantly in the experiments that followed, which were performed after 12, 25 and 42 days. During this period, bodyweight increased approximately by a factor of eight, and rapid growth of the stomach was observed histologically. Possible contributions for the development of the alimentary canal to the diminishment of intestinal protein assimilation are discussed.     

Dietary pantothenic acid requirement of fingerling Channa punctatus (Bloch) based on growth,feed conversion,liver pantothenic acid concentration and carcass composition

A 16‐week feeding trial was conducted to determine the dietary pantothenic acid requirement of fingerling Channa punctatus. Six casein–gelatin‐based diets (450 g/kg CP; 18.39 kJ/g GE) with graded levels of pantothenic acid (0, 10, 20, 30, 40 and 50 mg/kg diet) were fed to triplicate groups of fish (6.2 ± 0.71 cm; 4.26 ± 0.37 g) near to apparent satiation. The growth evaluation in terms of absolute weight gain (AWG), feed conversion ratio (FCR) and protein retention efficiency (PRE) indicated the best performance (p < .05) in fish fed diet containing 30 mg/kg pantothenic acid. Highest haemoglobin, haematocrit and RBCs counts were also obtained in fish fed diet with 30 mg/kg pantothenic acid. Mean cell haemoglobin and mean cell volume were found to be lowest in fish fed pantothenic acid‐free diet indicating the anaemia in this group of fish. Superoxidase dismutase and catalase activities of liver tissue were found to improve (p < .05) with the increasing levels of dietary pantothenic acid from 0 to 30 mg/kg. However, liver pantothenic acid concentration responded positively with the increasing levels of pantothenic acid up to 40 mg/kg diet and then stagnation in liver pantothenic acid concentration with the further inclusion of pantothenic acid was recorded. Second‐degree polynomial regression analysis of AWG, FCR and PRE exhibited the pantothenic acid requirement at 36.4, 32.8 and 34.7 mg/kg diet, respectively. Data generated during this study would be useful in formulating pantothenic acid‐balanced commercial feeds for the intensive culture of this fish.     

饲料中添加叔丁基氢醌对大菱鲆生长、血液生化指标、非特异性免疫及肠道组织结构的影响

为研究饲料中添加不同含量叔丁基氢醌(TBHQ)对大菱鲆幼鱼生长、血液生化指标、非特异性免疫及肠道组织结构的影响,在饲料中分别添加0、150、450和750 mg/kg的叔丁基氢醌,配制成4种等氮等脂实验饲料,选择初始体质量(8.31±0.04)g大菱鲆幼鱼,随机分成4组,每组6个重复,每个重复30尾,采用饱饲投喂方式,每天投喂2次,饲养周期为12 W。结果显示,与对照组相比,450和750 mg/kg TBHQ添加组大菱鲆的增重率、特定生长率均显著降低;450 mg/kg TBHQ添加组实验鱼血清碱性磷酸酶活力显著高于150 mg/kg TBHQ添加组;150 mg/kg TBHQ添加组实验鱼血清白蛋白和高密度脂蛋白含量显著低于对照组和450 mg/kg添加组;450 mg/kg TBHQ添加组鱼的血清肌酐含量显著高于对照组;150 mg/kg TBHQ添加组鱼的血清总蛋白含量显著低于对照组;饲料中添加高剂量的TBHQ能够显著升高血清中CAT、溶菌酶活力(450和750 mg/kg)及头肾吞噬细胞呼吸爆发活力(750 mg/kg);饲料中TBHQ添加量为750 mg/kg时,血清SOD活力显著降低;与对照组相比,饲料中添加450和750 mg/kg TBHQ能够显著降低中肠肠道绒毛长度与肠道直径比,而添加750 mg/kg TBHQ时中肠肠道做绒毛长度与肠道直径的比值显著降低。研究表明,饲料中TBHQ的添加量为150 mg/kg时,对大菱鲆幼鱼生长及生理生化指标无显著影响,而饲料中添加450 mg/kg以上的TBHQ则会对大菱鲆幼鱼的生长及生理状况产生一定负面作用。