饲料脂肪水平对杂交鲟幼鱼生长、饲料消化率、抗氧化水平和肌肉脂肪酸组成的影响

研究旨在探究饲料中不同脂肪水平对西伯利亚杂交鲟(Acipenser baerii Brandt♀×A. schrenckii Brandt♂)幼鱼生长、饲料消化率、血清生化指标及肌肉脂肪酸组成的影响。以鱼油为脂肪源,配制4种脂肪水平分别为5%(D05)、10%(D10)、15%(D15)和20%(D20)的等氮饲料。选用初始体重为(152.83±0.67) g的杂交鲟,随机分为4组,每组3个重复,每个重复25尾鱼。养殖周期为12周。结果显示,饲料中不同脂肪水平对杂交鲟的生长性能有显著影响(P<0.05)。其中, D15组杂交鲟幼鱼的末均重(FBW)、增重率(WGR)和特定生长率(SGR)显著高于D05、D10和D20组(P<0.05),饲料效率(FE)显著高于D05和D10组(P<0.05)。随着饲料中脂肪含量的增加,杂交鲟幼鱼脏体比(VSI)、肝体比(HSI)及肌肉、肝脏中的脂肪含量显著上升(P<0.05)。饲料中不同脂肪水平对干物质(ADCd)、蛋白质(ADCp)表观消化率无显著影响(P>0.05)。D10、D15和D20组脂肪表观消化率(ADCf)显...     

Growth performance and body composition of sub-yearling Persian sturgeon, (Acipenser persicus, Borodin, 1897), fed different dietary protein and lipid levels

In order to evaluate the protein and energy requirement of Persian sturgeon (Acipenser persicus) sub‐yearlings, eight experimental diets containing two protein levels (40% and 45%) and four lipid levels (10%, 15%, 20% and 25%) were tested. Sturgeons (W₀ = 136.8 g) were fed the experimental diets to satiation four times daily for 150 days, resulting in a final mean weight of 375.8 g. Growth was significantly affected by lipid content of the diets. At 40% protein level, weight gain and specific growth rate (% per day) were significantly improved (P < 0.05) by increasing the dietary lipid (energy) content. Protein efficiency ratio (PER) was significantly affected by different dietary treatments for each dietary protein level tested, reaching a mean value of 3.58 in fish fed high lipid diets and a PER of 2.77 in low lipid diets. Results obtained in the present study suggest that the optimum dietary protein content for Persian sturgeon is 40%, with an estimated optimum protein‐to‐energy ratio of 18–20 mg kJ⁻¹.     

Growth and haematological response of sturgeon hybrids Russian sturgeon (Acipenser guldenstadti brandt) × beluga (Huso huso L.) to protein and lipid contents in the diet

• 1.1. Fingerlings of intergenious hybrid Russian sturgeon (Acipenser guldenstadti) × beluga (Huso huso) weighing 22 g reared in water with salinity 18 ppt were fed nine diets differing in protein and fat content.
• 2.2. The increase of dietary protein content (from 45 to 52%) improved the fingerlings growth rate, food and protein conversion efficiencies. No effect of further protein content increase to 60% was observed.
• 3.3. The increase of dietary fat content from 10 to 20% positively influenced all growth results.
• 4.4. The muscular lipid content increased following the increase in dietary fat due to accumulation of triacylglycerols.
• 5.5. Distinctive leucopenia in neutrophils and leucophilia in lymphocytes following dietary protein and fat content increase were observed.
• 6.6. It was concluded that within the analysed range of values the increase of dietary protein and lipid content improved the physiological status of sturgeon hybrid fingerlings.

     

Effects of dietary prebiotic GroBiotic®‐A on growth performance,plasma thyroid hormones and mucosal immunity of great sturgeon,Huso huso (Linnaeus, 1758)

The present study was conducted to evaluate the effects of Grobiotic^®‐A, a commercial prebiotics, when administered in feed on the growth performance, plasma thyroid hormones and mucosal immunity of great sturgeon (Huso huso). The commercial prebiotic mixture was supplemented in the diets at four different levels (i.e. 0.0% as control, 0.5%, 1% and 2%, in three replicates, 20 fish per replicate) and fed to the fish for an 8‐week period wherein 240 fish were cultured in 1,800‐L fiberglass tanks that formed part of a flow‐through system. Water temperature was maintained at 20.4 ± 1.5°C. Significant changes in growth performance parameters were observed, but only in those groups fed with 1% and 2% prebiotics. Specifically, marked improvements relative to the control group were observed in percentage weight gain, body weight gain, feed conversion ratio and specific growth rate in prebiotic‐fed fish. The levels of plasma thyroid hormones, specifically thyroxine and thyroid stimulating hormones were significantly elevated in the group receiving 2% prebiotics. Activities of lysozyme and alkaline phosphatase in skin mucus were significantly enhanced in prebiotics‐fed groups, particularly at an inclusion level of 1% and higher (2% group compared to the control). Inhibitory activity of the skin mucus against pathogens, particularly Streptococcus iniae and Yersinia ruckeri, was significantly improved following prebiotic feeding. Taken together, dietary inclusion of GroBiotic^®‐A promoted growth, modulated thyroid hormones, and enhanced mucosal immunity of H. huso. This prebiotic mixture has the potential for use in improving the growth performance and health status of farmed great sturgeon.     

Effects of varying levels of dietary vitamin E (α‐tocopherol) on growth performance,proximate and fatty acid composition of juvenile silver pomfret (Pampus argenteus Euphrasen, 1788)

This study investigated the effects of elevated dietary levels of vitamin E (α‐tocopherol) on growth performance, proximate composition and fatty acid profiles of juvenile silver pomfret, Pampus argenteus. Three semi‐purified experimental diets were formulated to contain 49% protein and 16% lipid. High docosahexaenoic acid (DHA) tuna oil was added to the diets to supplement DHA. A graded level of vitamin E (0‐, 50‐, and 100 mg kg^?1) was added to experimental diets 1 to 3, respectively. Analyzed vit. E levels were 155.2, 195.3 and 236.4 mg kg^?1 in diets 1, 2 and 3, respectively. The experiment was conducted for 12 weeks with juvenile silver pomfret (29.6 ± 7.6 g) using a flow‐through system consisting of nine 1‐m³ tanks. Each treatment had three replicates and fish were stocked at the rate of 20 m^?3. Growth performance and feed utilization parameters of fish fed diets 2 and 3 were significantly (P < 0.05) higher than in fish fed diet 1, but the parameters in diets 2 and 3 did not differ significantly (P > 0.05). Although whole body protein levels were not influenced by the dietary vit. E levels, whole body lipid in fish fed diet 2 was significantly higher than in fish fed the other diets. The whole body vit. E levels in fish fed diet 2 (22.6 mg kg^?1) and diet 3 (24.1 mg kg^?1) were significantly (P < 0.05) higher than in those fed diet 1 (18.2 mg kg^?1). Whole body total saturated fatty acids were significantly lower, and DHA levels higher in fish fed diets 2 and 3 than those fed diet 1. The results of the present study suggest that increasing dietary supplementation of vit. E in high lipid diets enhances the growth performance of fish and that a dietary level of 196 mg kg^?1 vit. E is suitable for the growth of silver pomfret.     

Dietary Administration of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> Enhanced Growth Performance and Innate Immune Response of Siberian Sturgeon, <Emphasis Type="Italic">Acipenser baerii</Emphasis>

We investigated the effects of Lactobacillus plantarum used as a dietary supplement on the growth performance and innate immune response in juvenile Siberian sturgeon Acipenser baerii. Juvenile fish (14.6 ± 2.3 g) were fed three experimental diets prepared by supplementing a basal diet with L. plantarum at different concentrations [1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ colony-forming units (cfu) g^?1] and a control (non-supplemented basal) diet for 8 weeks. Growth performance indices were increased in fish fed the 1 × 10⁸ cfu g^?1 L. plantarum diet compared to the other groups. There was an increased innate immune response in fish fed the experimental diets. The highest levels of lysozyme activity, total immunoglobulin (IgM) and complement component 3 (C3) were observed in fish fed the diet containing L. plantarum at a concentration of 1 × 10⁸ cfu g^?1, but there was no significant difference in the level of complement component 4 (C4) in fish fed the experimental diets or the control diet. The present study underlying some positive effects (growth performance and immune indices) of dietary administration of L. plantarum at a concentration of 1 × 10⁸ cfu g^?1 in the Siberian sturgeon.     

高比例棉粕饲料中补充蛋氨酸对中华绒螯蟹幼蟹摄食、生长及抗氧化酶活性的影响

以40%棉粕为主的混合蛋白源制成基础饲料, 分别在其中添加0.00%、0.14%、0.28%、0.42%、0.56%蛋氨酸(分别记为0.00%Met、0.14%Met、0.28%Met、0.42%Met和0.56%Met), 配制了5种等氮等能的试验饲料, 以全鱼粉组(64.4%鱼粉)作为对照, 探讨了在高比例棉粕饲料中补充蛋氨酸对中华绒螯蟹幼蟹(0.390.02) g的摄食率、生长率和机体抗氧化酶活性的影响。结果表明: 与全鱼粉对照组相比, 0.42%Met组的增重率、特定生长率和饲料系数均无显著差异(P0.05), 但其显著高于0.00%Met、0.14%Met和0.28%Met组(P0.05); 增重率和特定生长率则显著高于0.56%Met组(P0.05); 从幼蟹的摄食量和蛋白质沉积率来看, 0.42%Met和0.28%Met组的摄食量与对照组相似, 当蛋氨酸的补充量低于0.28%或高于0.42%时, 幼蟹的摄食量均有所下降; 统计表明, 对照组的蛋白质沉积率最高(23.20%), 在各试验组中, 0.28%Met和0.42%Met组之间的蛋白质沉积率无显著差异(P0.05), 但显著高于0.00%Met、0.14%Met和0.56%Met组(P0.05); 分析幼蟹的肠道胰蛋白酶活性, 发现0.42%Met组与对照组之间无显著性差异(P0.05), 但均显著高于其他各试验组(P0.05); 0.28%Met、0.42%Met和0.56%Met处理组的血清丙二醛含量、超氧化物歧化酶活性和谷胱甘肽过氧化物酶活性与对照组无显著差异(P0.05)。结果提示, 在高比例植物蛋白(40%棉粕)的基础饲料中, 补充0.42%Met能够显著提高中华绒螯蟹幼蟹的生长率、消化率和抗氧化酶的活性。       

Effects of dietary l‐carnitine supplements on growth and body composition in beluga sturgeon (Huso huso) juveniles

The effects of dietary l ‐carnitine on growth performance, whole body composition and feed utilization were studied in beluga, Huso huso. Fish were randomly allocated in 15 tanks (30 fish per tank) and triplicate groups were fed to satiety during 84 days one of five isonitrogenous (41% CP) and isoenergetic (20 MJ kg^?1) diets, each differing in l ‐carnitine content [0 (control), 300, 600, 900 and 1200 mg kg^?1 diet]. At the end of the trial, fish grew from 19‐ to 23‐fold in weight, from 8.4 g to a maximum of 191 g. Fish fed 300–600 mg l ‐carnitine had the highest specific growth rate (SGR, 3.69 and 3.72% day^?1) and protein efficiency ratio (PER, 0.95 and 0.99), and the lowest feed conversion ratio (FCR, 1.4 and 1.3) than the other groups (P < 0.0001). SGR, PER and FCR were the poorest for fish fed 1200 mg l ‐carnitine, while fish fed the unsupplemented and 900 mg l ‐carnitine supplemented diet showed intermediate performance. Body lipid concentration decreased significantly from 5.8 to 5.1% (P < 0.0001) with dietary l ‐carnitine supplementation increasing from 0 to 300 mg. Energy content was significantly lower in fish fed the 900 and 1200 mg l ‐carnitine diet (5.8 MJ kg^?1), when compared with the other treatment groups (6.4–6.6 MJ kg^?1). The results indicated that feeding sturgeon on diets supplemented with 300 mg l ‐carnitine kg^?1 diet improved growth performance, and stimulated protein‐sparing effects from lipids.     

Growth performance,fatty‐acid composition,lipid deposition and hepatic‐lipid metabolism‐related gene expression in juvenile pond loach Misgurnus anguillicaudatus fed diets with different dietary soybean oil levels

A 10 week feeding trial was conducted to evaluate the effects of different dietary soybean oil (SO) levels on growth performance, fatty‐acid composition and lipid deposition in viscera, histology and histochemistry of liver, intestine and hepatic‐lipid metabolism‐related gene expressions in pond loach Misgurnus anguillicaudatus juveniles. Misgurnus anguillicaudatus (mean ± s.d. mass 0·40 ± 0·01 g) were fed five experimental diets containing SO at different concentrations: 0, 20, 32, 56 and 100% SO and a diet containing 100% fish oil (100% FO). The mass gains and specific growth rates of M. anguillicaudatus fed 20% SO and 100% FO diets were significantly higher than those of the other groups (P < 0·05). The lipid content of viscera and the amount of cytoplasmic vacuolation in the liver increased with incremental dietary SO level. Meanwhile, increasing dietary SO levels up‐regulated the messenger (m)RNA levels of lipogenic genes (such as Δ6fad, scd, pparγ, fas and srebp‐1) and down‐regulated the mRNA levels of the lipolytic genes (such as pparα, cpt1, atgl and hsl) in the liver. The percentage of 20:4n‐6 significantly (P < 0·05) increased with increasing dietary SO level, which might be correlated with the up‐regulation of the mRNA level of Δ6fad. The highest levels of dietary SO, however, had a negative effect on growth performance, lipid deposition of viscera and histology and histochemstry of liver and intestine. The increased lipid accumulation induced by incremental dietary SO level probably occurred through different strategies for lipid metabolism as a result of competition between lipolysis and lipogenesis and between export and import of lipids in this species.     

Dietary vitamin E supplementation affects tissue lipid peroxidation of hybrid tilapia,Oreochromis niloticus x O. aureus

A feeding trial was conducted to evaluate the effects of dietary vitamin E contents on the growth, ascorbate induced iron-catalyzed lipid peroxidation in post-mortem muscle and liver tissue, and Raman spectral changes in lens of juvenile hybrid tilapia (Oreochromis niloticus x O. aureus). Experimental fish were fed practical diets supplemented with 0, 50, 100, 200, 450 and 700 mg alpha-tocopheryl acetate/kg diet for 14 weeks. There was no significant difference in weight gain, feed conversion ratio and protein efficiency ratio among fish fed test diets (P>0.05). Protein content of fish fed diet containing the lowest vitamin E level was the lowest (P<0.05) among all groups. No difference was found in other body constituents among test fish (P>0.05). The thiobarbituric acid-reactive substances produced by iron-catalyzed lipid peroxidation in muscle and liver tissue of fish fed the diet without alpha-tocopheryl acetate supplementation were significantly (P<0.05) greater than those from fish fed diets containing higher levels of alpha-tocopheryl acetate. Dietary vitamin E supplementation increased the antioxidant capability of tilapia tissues against lipid peroxidation. Further, dietary vitamin E supplementation also influenced the lens cortical membrane structure of tilapia.     

异育银鲫幼鱼对饲料中缬氨酸需求量的研究

通过65d的生长实验, 探讨饲料中不同缬氨酸水平对异育银鲫(Carassius auratus gibelio)幼鱼平均体重(3.17±0.01)g/尾生长性能、饲料利用和蛋白利用的影响, 确定异育银鲫对饲料中缬氨酸的需要量。实验设计由酪蛋白、明胶和晶体氨基酸为蛋白源的8种等氮(蛋白含量:38%)等能(总能:17.0 kJ/g)的半精制饲料, 其缬氨酸水平等梯度逐步升高(0.54、0.79、1.04、1.29、1.54、1.79、2.04、2.29%饲料干物质)。各实验饲料中缬氨酸的实测值分别为:0.66、0.85、1.07、1.22、1.46、1.70、1.86和2.12%饲料干物质。饲料中其他必需氨基酸含量参照异育银鲫肌肉氨基酸模式。每种饲料饲喂3个重复,每个重复30尾鱼,养殖于塑料方箱中(70 cm×55 cm×50 cm;水体容积:150 L), 养殖系统为室内流水系统(500 mL/min流速), 每天两次饱食连续投喂(9:00和16:00)。实验结果表明,饲料中适量的缬氨酸显著提高了异育银鲫的特定生长率、饲料转化效率和蛋白沉积率(P0.05), 但显著影响了血清谷氨酰胺的浓度(P0.05), 但不同的缬氨酸水平显著影响了鱼体灰分含量(P<0.05)。对各处理组异育银鲫特定生长率的结果进行二次回归分析, 结果表明满足异育银鲫最大生长的缬氨酸需求量为饲料干物质的1.72%, 即占饲料蛋白的4.53%。       

Dietary methionine requirement of pre‐adult blunt snout bream, (Megalobrama amblycephala Yih, 1955)

A nine‐week feeding trial was conducted to test the hypothesis that an adequate methionine diet might improve growth, feed utilization, body composition and physiology, and biochemical parameters in pre‐adult blunt snout bream Megalobrama amblycephala, whereas a methionine deficiency might have adverse effects on these parameters. Six isonitrogenous and isoenergetics semi‐purified diets (33.0% crude protein, 7.0% crude lipid) were formulated to contain graded methionine levels (0.39–1.54% of dry weight) at 0.25% increments replaced by equal proportions of glycine. Results show that the survival rate (SR) was not significantly affected by the dietary methionine level. Final weight (FW), feed efficiency ratios (FER), weight gain (WG), and specific growth rate (SGR) increased with increasing dietary methionine levels up to 1.00% and then showed a declining trend. Using quadratic regression analysis of FER and SGR, the dietary methionine requirement was estimated to be 0.74% (2.24% of dietary protein) and 0.76% of the diet (2.30% of dietary protein), respectively. Fish fed the 0.39% methionine diet showed significantly lower whole body protein content compared to those fed with 0.85, 1.00 and 1.24% methionine diets (P < 0.05). Whole body moisture, lipid, and ash contents in pre‐adult adult blunt snout bream were not significantly affected. The urea content in fish fed the 0.85% methionine diet was significantly higher than those of fish fed a 0.39, 0.56, 1.24, 1.54% methionine diet (P < 0.05), but not significantly different in fish fed the 1.00% methionine diet (P > 0.05). No significant differences were found in other indexes such as the hepatosomatic index (HSI), viscerosomatic index (VSI), condition factor (CF), albumin (ALB), total protein (TP), alanine aminotransferase (ALT), and spartate transaminase (AST) (P > 0.05). Most important, the optimal dietary methionine level of pre‐adult blunt snout bream should be 0.74–0.76% of the diet (2.24–2.30% of dietary protein).     

亚麻油替代鱼油对杂交鲟生长、脂肪酸组成及脂肪代谢的影响

为研究亚麻油替代不同水平的鱼油后对杂交鲟(Acipenser baeri Brandt♀×A. schrenckii Brandt♂)幼鱼[初均重(70.8±0.5) g]生长、脂肪酸组成、肝脏及肌肉脂肪沉积以及脂肪代谢的影响, 在油脂添加量为8%的饲料中用亚麻油分别替代0(LO0)、25%(LO25)、50%(LO50)、75%(LO75)和100%(LO100)的鱼油, 配制5种等氮(38.7%CP)等脂(10%CF)饲料。每组饲料随机设3个重复, 养殖周期为12周。结果表明,亚麻油替代100%的鱼油对杂交鲟幼鱼的生长没有显著影响, 而且随着饲料中亚麻油含量的上升, 饲料效率有所提高, 100%鱼油替代组的饲料效率明显高于100%鱼油组的(P<0.05); 但用亚麻油替代鱼油后, 肌肉和肝脏的粗脂肪含量以及血清中谷草转氨酶、谷丙转氨酶和乳酸脱氢酶活性明显升高(P<0.05); 肌肉亚麻酸和n-3多不饱和脂肪酸的含量与饲料中相应脂肪酸组成呈明显的线性相关关系(R2>0.69; P<0.05)。对于杂交鲟的脂肪代谢而言, 亚麻油的添加对血清中的游离脂肪酸、甘油三酯、高、低密度脂蛋白胆固醇的变化产生明显影响, 但亚麻油对血清总胆固醇和酮体影响不显著。考虑到亚麻油完全替代鱼油后, 肌肉中的EPA和DHA这两种长链高不饱和脂肪酸的含量仅下降了不到30%, 因此亚麻油应该是一种比较优质的鱼油替代品。     

The influence of dietary fatty acid composition on the respiratory and cardiovascular physiology of Adriatic sturgeon (Acipenser naccarii): a review

This paper reviews evidence that the fatty acid composition of dietary lipids influences the respiratory and cardiovascular physiology of Adriatic sturgeon {Acipenser naccarii) and, thereby, their tolerance of the stress of hypoxia. Sturgeon fed a commercial diet enriched in fish oil (menhaden oil as 15% of dry feed weight), with an elevated content of highly unsaturated fatty acids of the co3 series (ω3 HUFA), had a significantly lower standard metabolic rate (SMR) and routine oxygen consumption (Mo₂) than those fed a diet enriched with the same quantity of hydrogenated coconut oil, with an elevated content of saturated fatty acids (SFA). Both groups grew equally well. As a result of this difference in aerobic metabolism, sturgeon fed the w3 HUFA and SFA responded differently when exposed to hypoxic challenges. Sturgeon fed w3 HUFA exhibited no significant reflex hyperventilation when exposed to mild, moderate or deep hypoxia (30 min at water 0₂ partial pressures of 10.8, 6.6 and 4.6 kPa, respectively), no hypoxic depression of spontaneous activity during 3h in mild hypoxia, and no depression of Mo₂ during 3h in moderate hypoxia, unlike sturgeon fed SFA. The diets also influenced the performance of isolated hearts in vitro. Hearts from fish fed o3 HUFA maintained maximum in vitro cardiac power output unchanged when oxygen supply was reduced (O₂ content from 2.3 to 0.7 vol.%), unlike hearts from sturgeon fed SFA. Overall, the results indicate that dietary fatty acid composition can influence tolerance of hypoxia in sturgeon, through effects on SMR. When compared to sturgeon fed SFA, those fed co3 HUFA had lower SMR and were more tolerant of hypoxia, with effects both on the whole animal and on the isolated heart.     

Hemato-Immunological Responses and Disease Resistance in Siberian Sturgeon <Emphasis Type="Italic">Acipenser baerii</Emphasis> Fed on a Supplemented Diet of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis>

A feeding trial was conducted to investigate the effects of different levels of dietary Lactobacillus plantarum on hemato-immunological parameters and resistance against Streptococcus iniae infection in juvenile Siberian sturgeon Acipenser baerii. Fish (14.6 ± 2.3 g) were fed three experimental diets prepared by supplementing a basal diet with L. plantarum at different concentrations [1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ colony-forming units (cfu) g^?1] and a control (non-supplemented basal) diet for 8 weeks. Innate immune responses (immunoglobulin (Ig), alternative complement activity (ACH50) and lysozyme activity) were significantly higher in fish fed the 1 × 10⁸ and 1 × 10⁹ cfu g^?1 L. plantarum diet compared to the other groups (P < 0.05). Furthermore, fish fed on various levels of L. plantarum significantly showed higher red blood cell (RBC), hemoglobin (Hb), white blood cell (WBC) and monocyte compared to those of the control group (P < 0.05). At the end of the feeding experiment, some fish were challenged with S. iniae to quantify the level of disease resistance. The mortality after S. iniae challenge was decreased in fish fed a probiotic. These results indicated that dietary supplementation of L. plantarum improved immune response and disease resistance of Siberian sturgeon juvenile.     

Effectiveness of Maifanite in Reducing the Detrimental Effects of Cadmium on Growth Performance, Cadmium Residue, Hematological Parameters, Serum Biochemistry, and the Activities of Antioxidant Enzymes in Pigs

This study was conducted to investigate the toxicity of cadmium and to evaluate the effectiveness of maifanite in preventing cadmium-induced adverse effects. Thirty-two crossbred pigs (Duroc × Landrace × Large white, sex balanced, 17.25?±?0.07 kg average body weight) were randomly allotted to one of four dietary treatments in a 2?×?2 factorial arrangement, with eight replicates per treatment and one pig per replicate. The dietary treatments included two cadmium (as CdCl₂) doses (0.32 and 30.49 mg/kg) and two maifanite doses (0 and 1 %). The results showed that pigs treated with cadmium decreased their average daily feed intake (P?<?0.05) and increased (P?<?0.05) the feed/gain ratio. Cadmium was found in the tissues of pigs that were fed with cadmium-contaminated diets, but the level of cadmium was much lower when maifanite was added to the cadmium-contaminated diets. Ingestion of diets that were artificially contaminated with cadmium (30.49 mg/kg of cadmium) reduced (P?<?0.05) the number of lymphocytes, the total erythrocyte count, the hemoglobin level, and the hematocrit. However, the activities of serum aspartate aminotransferase and gamma glutamyltransferase were increased (P?<?0.05). The total protein level was lower (P?<?0.05) in pigs fed with cadmium-contaminated diets. The contents of malondialdehyde increased (P?<?0.05), while the total antioxidant capacity and the activities of total superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and catalase decreased (P?<?0.05) in pigs fed with cadmium-contaminated diets. Dietary addition of maifanite can, to some extent, prevent the negative effects associated with feeding cadmium diets (30.49 mg/kg of cadmium) to pigs.     

Reevaluation of dietary methionine requirement by plasma methionine and ammonia concentrations in surgically modified rainbow trout,Oncorhynchus mykiss

This study aimed to reevaluate the dietary methionine requirement by means of the plasma methionine and ammonia concentrations in surgically modified rainbow trout, Oncorhynchus mykiss. A total of 35 rainbow trout averaging 505 ± 6.5 g (initial body weight, mean ± SD) were randomly distributed into seven groups with five fish in each group. After 48 h of food deprivation, each group was fed one of seven L‐amino acid‐based diets containing graded levels of methionine (0.25, 0.40, 0.50, 0.60, 0.70, 0.80 or 0.95% of diet, dry matter bases) by intubation at 1% bodyweight. Blood samples were taken at 0, 5 and 24 h after intubation. Post‐prandial plasma free methionine concentrations (PPmet, 5 h after intubation) and post‐absorptive plasma free methionine concentrations (PAmet, 24 h after intubation) of fish fed diets containing 0.60% or more methionine were significantly (P < 0.05) higher than those of fish fed diets containing 0.50% or less methionine. PPmet and PAmet in fish fed diets containing 0.60% or higher methionine were not significantly different except the PPmet of fish fed a diet containing 0.95% methionine. Post‐prandial plasma ammonia concentrations (PPA, 5 h after intubation) of fish fed diets containing 0.70% or more methionine were significantly higher than those of fish fed diets containing 0.60% or less methionine, and PPA of fish fed diets containing 0.25% and up to 0.60% methionine were not significantly different from each other. Broken‐line model analyses on PPmet, PAmet, and PPA indicated that the dietary methionine requirement of rainbow trout was between 0.59% (1.69) and 0.67% (1.91) of diets (% dietary protein bases) when the diets contained 0.5% cystine.     

Influence of Butyrate Loaded Clinoptilolite Dietary Supplementation on Growth Performance,Development of Intestine and Antioxidant Capacity in Broiler Chickens

The study was conducted to evaluate the effects of dietary butyrate loaded clinoptilolite (CLI-B) on growth performance, pancreatic digestive enzymes, intestinal development and histomorphology, as well as antioxidant capacity of serum and intestinal mucosal in chickens. Two hundred forty 1-day-old commercial Arbor Acres broilers were randomly assigned to 4 groups: CON group (fed basal diets), SB group (fed basal diet with 0.05% sodium butyrate), CLI group (fed basal diet with 1% clinoptilolite), and CLI-B group (fed basal diet with 1% CLI-B). The results showed that supplementation of CLI-B significantly decreased (P < 0.05) feed conservation ratio at both 21 and 42 days of age, improved the pancreatic digestive enzymes activities (P < 0.05), increased the villus length and villus/crypt ratio (P < 0.05), and decreased the crypt depth of intestine (P < 0.05) as compared to the other experimental groups. Furthermore, the CLI-B environment improved the antioxidant capacity by increasing the antioxidant enzyme activities (P < 0.05) in intestine mucosal, and decreasing the NO content and iNOS activity (P < 0.05) in serum. In addition, CLI-B supplementation had improved the development of intestine and antioxidant capacity of broilers than supplementation with either clinoptilolite or butyrate sodium alone. In conclusion, 1% CLI-B supplementation improved the health status, intestine development and antioxidant capacity in broiler chickens, thus appearing as an important feed additive for the poultry industry.     

Dietary amino acid l‐histidine requirement of fingerling Indian catfish,Heteropneustes fossilis (Bloch), estimated by growth and whole body protein and fat composition

An eight‐week feeding trial was conducted to determine the dietary histidine requirement of Indian catfish, Heteropneustes fossilis (6.20 ± 1.25 cm, 4.65 ± 0.48 g) in 75‐L flow‐through circular troughs. Six isonitrogenous (40%) and isoenergetic (17.90 kJ g^?1) amino acid test diets with graded levels of l ‐histidine (0.25 – 0.75%, dry diet), in gradation of 0.10% histidine were formulated. Fish were randomly stocked in triplicate groups and fed experimental diets at 4% BW per day at 08:00 and 18:00 h. Maximum live weight gain (288%), best FCR (1.40) and PER (1.78) were occurred at 0.55% dietary histidine level. For the live weight gain, FCR, PER and body protein deposition data were examined using quadratic regression analysis, the breakpoints indicating requirements for histidine at 0.58, 0.54, 0.53 and 0.54% of dry diet, respectively. Significantly (P < 0.05) low moisture and higher whole body protein content were obtained in the 0.55% histidine diet, while body fat showed an increasing trend with the increase in dietary concentrations. Ash content remained insignificantly (P > 0.05) low among all dietary groups, except in diet I and diet II. Based on the above results, the recommended diet for young H. fossilis should contain histidine at 0.54% of dry diet, corresponding to 1.35% of dietary protein for optimum growth and efficient feed utilization.     

饲料蛋白和脂肪水平对青鱼大规格鱼种生长和体组成的影响

设计5个饲料蛋白水平（30%、33%、36%、39%和42%）和2个脂肪水平（6%和9%）的52的因子试验,配制10种试验饲料,分别饲喂10组三重复平均体重为95.5 g的二龄青鱼70d,以探讨不同蛋白和脂肪水平对青鱼生长和体组成等的影响。结果表明: 鱼体增重随饲料蛋白水平从30%提高到39%不断增加（P0.05）,进一步提高饲料蛋白水平至42%时,鱼体增重则不再显著变化（P0.05）;饲料系数随饲料蛋白水平从30%提高到39%而不断降低（P0.05）,进一步提高饲料蛋白水平至42%时,也不再显著变化;蛋白质效率和蛋白保留率随饲料蛋白水平呈下降趋势;以鱼体增重为指标,经折线模型进行回归分析求得适宜的饲料蛋白水平为占干饲料的40%。饲料蛋白、脂肪水平及其交互作用对的试验鱼成活率均无显著差异（P0.05）。饲料脂肪水平、饲料蛋白与脂肪的交互作用对鱼体增重、饲料系数、摄食率和蛋白质效率也均无显著影响（P0.05）。摄食蛋白水平为30%和33%饲料的青鱼与摄食蛋白水平36%-42%饲料的青鱼相比,有较低的水分和较高全鱼脂肪（P0.05）。青鱼脏体比和肌肉粗脂肪含量均随着饲料中蛋白水平的提高呈降低的趋势。摄食脂肪水平为9%的饲料的青鱼较摄食脂肪水平为6%的饲料的青鱼,有较高脏体比、全鱼脂肪含量和肌肉粗脂肪含量（P0.05）。上述结果说明,青鱼摄食低蛋白和高脂肪的饲料造成过多的体脂积累。在试验条件下,青鱼大规格鱼种饲养阶段适宜的饲料蛋白和脂肪水平分别为占干饲料的40%和6%。