克氏螯虾饲料中适宜的蛋白质含量和能量蛋白比研究

采用3×3因子试验法,设计了3种不同蛋白质水平(26%、29%、32%)及能最蛋白比水平(36、40、44 kl/g)的9种试验饲料,对体重(2.39±0.37)g的克氏螯虾(Procambarus clarkii)的适宜蛋白质含量及其蛋白能最比进行了研究,生长试验期42 d.结果表明,克氏螫虾幼虾配合饲料中适宜蛋白质含量为29.49%～32.24%,饲料的适宜能量蛋白比范嗣为34.67～37.46 kJ/g;当试验饲料蛋白质含量为31.86%,能量蛋白比为35.85 kJ/g时,试验虾获得最大增重率、最低的饲料系数、最高的蛋白质效率及最大的特定生长率.     

卵形鲳鲹幼鱼饲料中适宜蛋白能量比的研究

以鱼粉、豆粕为蛋白源,豆油、鱼油为脂肪源,配制9种不同蛋白能量水平的饲料,蛋白质3个水平(38%、43%、49%),每个蛋白水平设3个脂肪梯度(6%、10%、14%),其蛋白能量比为19.3～27.4mg/kJ。卵形鲳鲹初始质量为(25.02±0.16)g,每个处理设3个重复,每个网箱(1.5 m×1.0 m×2.0m)放养卵形鲳鲹苗20尾,养殖试验持续8周。结果显示,卵形鲳鲹特定生长率随饲料蛋白水平的升高而显著升高(P<0.05)。投喂含43%或49%蛋白质、6%脂肪饲料的卵形鲳鲹表现出较好的特定生长率。饲料中不同的脂肪水平未表现出蛋白质节约效应,较高的脂肪水平反而抑制了卵形鲳鲹的特定生长率、饲料效率和蛋白质效率。卵形鲳鲹鱼体蛋白和脂肪含量分别随饲料蛋白质和脂肪水平的上升而显著升高(P<0.05)。在该试验条件下,卵形鲳鲹幼鱼饲料中最适蛋白质、脂肪水平和蛋白能量比分别为43%、6%和24.4 mg/kJ。     

鱼类饲料中适宜蛋白质能量比研究的进展

能量是鱼类饲料组成定量的基础指标之一, 但与畜禽不同,鱼类对饲料蛋白质的需要量较高[1],在饲料中往往被优先考虑.已有研究证实,碳水化合物与脂肪有节约蛋白质的作用[2].     

青鱼饲料最适能量蛋白比的研究

用酪蛋白和明胶作为饲料蛋白源，配以豆油、糊精和纤维素粉及适量的维生素和矿物混合剂组成精制试验饲料。将其调制成五个蛋白水平，每个蛋白水平分别包括五个能量级，以青鱼(Mylopharyngodon piceus)鱼种为试验对象，经过60天的喂养试验，用净增率、蛋白质效率(PER)和饲料系数等作为评定指标。结果表明：青鱼鱼种配合饲料中的蛋白质含量为35～40％；饲料能量蛋白比(即C／P值)为9．1千卡／克蛋白；每公斤饲料的总能量为3185～3640千卡是最为适宜的。上述这些数据是制定应用饲料配方的主要理论依据。试验还发现，青鱼鱼种对糊精之类的碳水化合物具有较大的利用能力；试验证明：可利用的碳水化合物具有较好的节约饲料蛋白的作用。     

鲤鱼饲料的最佳能量蛋白比

为搞清鲤鱼饲料中最佳能量蛋白比[可消化能(DE，千焦／公斤饲料)与蛋白质(P，呖)之比；DE／P]进行了饲养试验，方法是给鲤鱼投喂含营养量不等的(蛋白质(22%-41％)、碳水化合物(5%-50%)和类脂(5%-15%)]各种配合饲料，结果表明，不管饲料中的DE如何，喂蛋白质含量23%饲料的鱼，其生长速度和喂养变化相当慢．当饲料的DE达1298-1507千焦／100克、蛋白质含量达31%-32%时，生长速度最快．使用碳水化合物或类脂把饲料中的DE从1298千焦提高到1292千焦，其生长速度、饵料系数等没什么变化．喂消化能量小于1298千焦的饲料时，PER(饲料蛋白质的蛋白效率)和NPU(净蛋白利用率)值低得多．不管饲料中消化能量比或鱼的生长情况如何，鲤鱼体中能量转化率在32%～49%．另外能量消化率与饲料的纤维素含量呈线性关系，随着饲料纤维素含量的增加而减小．根据试验结果分析数据推测，鲤鱼生长所需饲料的最佳蛋白质含量是31%左右，据消化能的测定，生长所需最佳的能量蛋白比(DE／P)的试验值是406-486．     

细说饲料蛋白质含量

蛋白质是构成生命的物质基础,也是能量来源之一,为修补组织、增长身体不可缺少的营养。鱼体所需的蛋白质只能从饲料中来提供。 蛋白质主要由碳、氢、氧、氮四种元素组成,有的蛋白质还含有硫（如角蛋白）、磷（如奶蛋白）、铁（如血红蛋白）、镁（如叶绿蛋白）等。     

不同蛋白能量比饲料对草鱼幼鱼消化酶活性的影响

以鱼粉和豆粕为蛋白源,鱼油和豆油等比例混合油为脂肪源,共配制4个蛋白水平(20%、25%、30%、35%),每一蛋白水平设4个脂肪水平(4.5%、8%、11.5%、15%),共16组饲料。每组设3个重复,在水温23~29℃下,连续投喂初始体重为(16.84±0.28)g的草鱼(Ctenopharyngodon idellus)10周,研究不同蛋白能量比饲料对草鱼幼鱼消化酶活性的影响。结果显示:肠道蛋白酶的活性随着饲料蛋白含量的升高而显著升高(P<0.05),饲料蛋白水平在20%~30%时,饲料中的脂肪水平对蛋白酶活性影响不显著(P>0.05),蛋白水平在35%时,高脂肪抑制了蛋白酶活性,肝胰脏的蛋白酶变化规律类似于肠道;肠道和肝胰脏淀粉酶活性在饲料蛋白含量相同的情况下,随着脂肪含量的升高呈现显著的下降趋势(P<0.05),但饲料中蛋白(30%,35%)和脂肪(8%,11.5%,15%)含量较高时,淀粉酶活性较稳定;肠道和肝胰脏的脂肪酶活性在饲料蛋白含量相同的情况下,随着脂肪含量的升高,呈显著上升的趋势(P<0.05),但在蛋白含量(30%,35%)和脂肪含量(8%、11.5%,15%)的6个试验组之间差异不显著(P>0.05);在脂肪含量分别为4.5%、8%和11.5%时,饲料的蛋白含量对肠道的脂肪酶活性无显著性影响(P>0.05),当脂肪含量为15%时,随着蛋白含量的升高,肠道的脂肪酶活性显著降低(P<0.05)。结果表明,草鱼饲料中蛋白含量为30%和脂肪为8%(即蛋白能量比21.7 mg/kJ)的试验组草鱼获得较高的消化酶活性。     

美洲鲥幼鱼饲料中蛋白质的适宜含量

为研究饲料中不同蛋白质含量对美洲鲥幼鱼生长的影响,设置了蛋白质含量分别为35%、40%和45%的3组实验,经过41d的试验得出:蛋白质含量为40%的饲料组,幼鱼的增重率、特定生长率最高(P<0.05);蛋白质含量为40%组和45%组的蛋白质效率和饲料转化率无显著差异(P>0.05),但均高于35%组(P<0.05)。     

稚鳖饲料适宜蛋白含量的研究

用蛋白质梯度法,以白鱼粉为蛋白源,对稚鳖蛋白质需求进行测定。试验期间水温28 3℃,420只稚鳖平均体重(11 23±0 93)g,分成7个组,每组3个重复,饲养60d。结果表明,蛋白质质量分数50 91%、54 81%生长较好,稚鳖饲料粗蛋白适宜质量分数应为49 52%。     

日本沼虾饲料最适蛋白质、脂肪含量及能量蛋白比的研究

本文研究了日本沼虾(Macrobrachium nipponense)饲料的最适蛋白质含量、脂肪含量及能量蛋白比。试验用饲料由酪蛋白、糊精、混合油、复合维生素和无机盐混合物等组成。本试验用的日本沼虾体重为 1.77±0.23克,试验期间水温为 21—25℃。用增重率、饲料系数和肝胰脏α-淀粉酶活力等作为评价指标。试验结果表明:日本沼虾配合饲料适宜蛋白质含量为 36.8—42.27％,适宜脂肪含量为6—12％。当配合饲料的蛋内质含量在适宜范围内,饲料能量蛋白比(C/P)为8千卡/克蛋白左右,每公斤配合饲料的总能量为3006—3561千卡是最为适宜的。当饲料总能量在一定范围内,随着饲料碳水化合物含量的增加,肝胰脏α-淀粉酶活力增强。     

Effects of dietary protein to energy ratios on growth and body composition of juvenile Chinese sucker,Myxocyprinus asiaticus

A growth experiment was conducted to investigate effect of dietary protein to energy ratios on growth and body composition of juvenile Myxocyprinus asiaticus (initial mean weight: 10.04 ± 0.53 g, mean ± SD). Nine practical diets were formulated to contain three protein levels (340, 390 and 440 g kg^?1), each with three lipid levels (60, 100 and 140 g kg^?1), in order to produce a range of P/E ratios (from 22.4 to 32.8 mg protein kJ^?1). Each diet was randomly assigned to triplicate groups of 20 fish in 400‐L indoors flow‐through circular fibre glass tanks provided with sand‐filtered aerated freshwater. The results showed that the growth was significantly affected by dietary P/E ratio (P < 0.05). Fish fed the diets with 440 g kg^?1 protein (100 and 140 g kg^?1 lipid, P/E ratio of 31.43 and 29.22 mg protein kJ^?1) had the highest specific growth rates (SGR) (2.16 and 2.27% day^?1, respectively). However, fish fed the diet with 390 g kg^?1 protein and 140 g kg^?1 lipid showed comparable growth (2.01% day^?1), and had higher protein efficiency ratio (PER), protein productive value (PPV) and energy retention (ER) than other groups (P < 0.05). No significant differences in survival were found among dietary treatments. Carcass lipid content was positively correlated with dietary lipid level, but irrespective of protein level and inversely correlated with carcass moisture content. Carcass protein contents increased with increasing dietary lipid at each protein level. The white muscle and liver composition showed that lipid increased with increasing dietary lipid level (P < 0.05). Dietary protein concentrations had significant effect on condition factor (CF), hepatosomatic index (HSI) and viscerosomatic index (VSI) (P < 0.05). However, dietary lipid concentrations had no significant effect on CF, HSI (P > 0.05). Based on these observations, 440 g kg^?1 protein with lipid from 100 to 140 g kg^?1 (P/E ratio of 29.22 to 31.43 mg protein kJ^?1) seemed to meet minimum requirement for optimal growth and feed utilization, and lipid could cause protein‐sparing effect in diets for juvenile Chinese sucker.     

Dietary phosphorus requirement of juvenile Chinese sucker,Myxocyprinus asiaticus

A growth trial was conducted to estimate the optimum requirement of dietary available phosphorus (P) for Chinese sucker juveniles. Triplicate groups of juveniles Chinese sucker (initial mean weight: 1.77 ± 0.02 g, mean ± SD) were fed diets containing graded levels (3.1, 5.3, 7.5, 9.6 and 11.8 g kg^?1) of available phosphorus. The basal diet (diet 1), containing 3.1 g kg^?1 available P, was supplemented with graded levels of monocalcium phosphate to formulate four experimental diets. The fish were fed twice daily (08:00 and 17:00 h) to satiation for 8 weeks. During the experimental period, the water temperature fluctuated from 27.5 to 30.5 °C and dissolved oxygen was more than 6 mg L^?1. The specific growth rate, protein efficiency ratio were all significantly increased by dietary available phosphorus up to 7.5 g kg^?1 (P < 0.05) and then levelled off beyond this level. Feed conversion ratio significantly decreased with dietary available phosphorus level up to 7.5 g kg^?1 (P < 0.05). Dietary treatments did not significantly affect feed intake (P > 0.05). Efficiency of phosphorus (P) utilization significantly decreased with dietary available phosphorus level (P < 0.05). Body composition analysis showed that the whole‐body lipid, ash, calcium, phosphorus, magnesium (Mg), zinc (Zn) and copper (Cu) contents were all significantly affected by dietary available P concentration (P < 0.05); however, no significance were found for manganese (Mn) concentration and calcium/phosphorus (Ca/P) ratios in whole‐body among all the treatments (P > 0.05). Dietary phosphorus levels also significantly affected the mineralization of vertebrae and scale (P < 0.05), and Ca/P ratios in scale were not influenced by dietary P supplementation, while vertebrae Ca/P ratio decreased with dietary available P levels (P < 0.05) (quadratic effect, P < 0.001). Signs of phosphorus deficiency were characterized by poor growth, slightly reduced mineralization and an increase in body lipid content. The blood chemistry analysis showed that dietary available P had distinct effects on enzyme activities of alkaline phosphatase, as well as contents of triacyglycerol and total cholesterol (P < 0.05). Broken‐line analysis based on weight gain indicated the minimum available phosphorus requirement for the optimal growth of juvenile Chinese sucker was 7.4 g kg^?1. Based on the phosphorus content in whole body, vertebrae or scale indicated that the requirements were 8.3, 8.8 and 8.6 g kg^?1 respectively.     

Dietary vitamin C requirement of juvenile Chinese sucker (Myxocyprinus asiaticus)

An 8‐week growth experiment was conducted to quantify the appropriate dietary vitamin C requirement of juvenile Chinese sucker (Myxocyprinus asiaticus). Triplicate groups of 30 experimental fish [initial body weight: (7.1 ± 0.3) g] were cultured in 500 L aquaria and fed with semi‐purified diets containing six levels [10.1 (unsupplemented diet), 37.4, 64.9, 125.2, 244.2 and 482.0 mg kg^?1 diet, respectively] of vitamin C (supplied as L‐ascorbyl‐2‐polyphosphate). Results showed that weight gain of Chinese sucker was significantly increased with increasing dietary vitamin C levels, but there was no significant difference of weight gain among fish fed the diets containing more than 125.2 mg kg^?1 vitamin C. As dietary vitamin C increased, the liver vitamin C content of fish showed the increasing trend firstly and then stabled, while the muscle vitamin C content significantly increased without reaching a constant level. Lower liver malondialdehyde content was observed in 125.2, 244.2 and 482.0 mg kg^?1 vitamin C groups, and higher antioxidant capacity and superoxide dismutase activities were observed in supplemented groups when compared to the unsupplemented group. Liver aspartate aminotransferase and alkaline phosphatase activities were also significant affected by dietary vitamin C. Ash content of fish fed the diet with 244.2 or 482.0 mg kg^?1 vitamin C was significantly higher than that of fish fed the other diets. However, dietary vitamin C had no significant effects on whole‐body crude protein, lipid and moisture contents. The vitamin C requirement of juvenile Chinese sucker was estimated to be 84.6 and 126.1 mg kg^?1 based on weight gain and liver vitamin C concentration respectively.     

Dietary l‐lysine requirement of juvenile Chinese sucker,Myxocyprinus asiaticus

An 8‐week feeding trial was conducted to quantify the dietary l ‐lysine requirement of juvenile Chinese sucker with an initial weight of 1.81 ± 0.04 g reared in indoor flow‐through and aerated tanks. Six isonitrogenous and isoenergetic practical diets were formulated to contain graded levels of lysine (1.23%, 1.80%, 2.39%, 2.98%, 3.56% and 4.18% dry matter) at 0.6% increments from dietary ingredients and crystalline l ‐lysine. Each diet was randomly assigned to triplicate groups of 30 fish each and was fed to apparent satiation by hand three times a day (09:00, 13:00 and 17:00 hours) for 8 weeks. There were significant differences in growth performance and feed utilization among the treatments. Weight gain (WG), specific growth rate and protein efficiency ratio (PER) significantly increased with increasing lysine levels up to 2.39% of diet (P < 0.05) and remained nearly the same thereafter (P > 0.05). Feed efficiency was the poorest for fish fed the lowest lysine diet (P < 0.05) and showed no significant differences when dietary lysine level increased from 2.39% to 4.18%. The N retention (% N intake) significantly increased with dietary lysine level but did not attain a plateau (P < 0.05). Survival could not be related to dietary treatments. Whole body protein increased (P < 0.05) and whole body lipid decreased (P < 0.05) with increasing dietary lysine level. The condition factor and hepatosomatic index were significantly affected by dietary lysine levels, however, viscersomatic index, whole body moisture and ash did not differ significantly among dietary treatments. Broken‐line analysis on the basis of WG and PER showed that dietary lysine requirements of juvenile Chinese sucker were 2.43% and 2.40% dry diet (5.52% and 5.45% dietary protein) respectively. Based on the ideal protein approach and the A/E ratios determined from muscle amino acid profile an estimation of the EAA requirements of Chinese sucker juveniles were calculated.     

环境因子对胭脂鱼精子活力影响的研究

通过观察精子的快速运动时间和寿命,研究了6种环境因子对胭脂鱼(Myxocyprinus asiaticus Bleeker)精子活力的影响。结果表明:胭脂鱼精子对酸碱的耐受能力较强,在pH值为4~10时,精子均可以快速运动,且在pH值为8时精子的活力最强。不同浓度的NaCl、KCl、葡萄糖、CaCl2、MaCl2溶液对胭脂鱼精子运动的诱导效果不同。5种溶液最适于胭脂鱼精子运动的浓度分别为:NaCl 102 mmol/L;KCl 75 mmol/L;葡萄糖100 mmol/L;CaCl275.6 mmol/L;MgCl275.6 mmol/L。且在5种溶液低浓度时精子活力较强,超过一定浓度精子的运动开始被抑制。     

Optimal dietary methionine requirement of juvenile Chinese sucker,Myxocyprinus asiaticus

A total of 630 juvenile Chinese sucker, with an average initial weight of 1.72 ± 0.05 g, were fed seven diets for 56 days to study the effect of dietary methionine levels on growth, feed utilization, body composition and haematological parameters on juvenile Chinese sucker. Diet 1 using fish meal as the sole protein source and diets 2–7 using fish meal and fermented soybean meal as intact protein sources supplemented with crystalline amino acids contained six levels of l ‐methionine ranging from 6.4 to 18.9 g kg^?1 of dry diet at a constant dietary cystine level of 3.7 g kg^?1. Each diet was randomly assigned to three aquaria. Results indicated that the highest weight gain, specific growth rate (SGR), feed efficiency ratio, protein efficiency ratio and protein productive value occurred at 13.9 g methionine kg^?1 diet among the methionine supplemented dietary groups, beyond which they showed declining tendency. The whole body and muscle protein contents of juvenile Chinese sucker were positively correlated with dietary methionine level, while muscle lipid content was negatively correlated with it. The total essential amino acids content of muscle was increased significantly with increasing dietary methionine level from 6.4 to 13.9 g kg^?1 (P < 0.05). Apparent digestibility coefficients of dietary protein were significantly affected by dietary treatments. Serum protein, cholesterol and triacylglycerol increased with increasing dietary methionine levels, but showed a relatively lower value for fish fed the 18.9 g methionine kg^?1 diet. Quadratic regression analysis of SGR against dietary methionine level indicated that optimal dietary methionine requirement for juvenile Chinese sucker was 14.1 g kg^?1 of the diet in the presence of 3.7 g kg^?1 cystine (corresponding to 32.0 g kg^?1 of dietary protein on a dry‐weight basis).     

野外采集和人工繁育胭脂鱼形态差异研究

为了有效区分野外采集和人工繁育胭脂鱼（ Myxocyprinus asiaticus）群体,对四川省水产研究所（ SCC）、宜宾珍稀水陆生动物研究所（ YBC ）、重庆市万州水产研究所（ WZC ）的150尾人工繁育胭脂鱼和长江干流泸州（ LZW）、木洞（ MDW）、万州（ WZW）的112尾野外采集胭脂鱼进行了形态学差异分析。主成分分析、判别分析、聚类分析和形态学差异系数分析显示： WZC和YBC形态较相似,而与SCC在背鳍长/体长、尾鳍上叶长/体长、眼径/体长等特征上区别明显; WZW与MDW形态相似,而与LZW在臀鳍基后尾柄高/体长、吻长/体长、头长/体长、眼后头长/体长、头高/体长等特征上有区别; WZW与SCC形态相似度较大,而MDW与WZC、 YBC形态相似度较大。结果表明通过形态学分析无法有效区分野外采集和人工繁育胭脂鱼群体。     

胭脂鱼幼鱼的耗氧率及窒息点研究

在自制的可控温密封式流水呼吸室内,对0+龄胭脂鱼(Myxocyprinus asiaticus)的耗氧率和耗氧量进行了测定,并对0+龄和1+龄胭脂鱼的窒息点和窒息过程作了分析。结果显示,平均体重6~7 g的0+龄胭脂鱼在15℃时的平均耗氧率和耗氧量分别为0.0585 mg/(g.h)和0.3567 mg/(尾.h);20℃时的平均耗氧率和耗氧量为0.1176 mg/(g.h)和0.8232 mg/(尾.h);昼间耗氧率与夜间耗氧率未显差异。15、20、25和30℃下0+龄胭脂鱼的窒息点分别为0.4921、0.8319、0.9356和1.5144 mg/L,25和30℃下1+龄胭脂鱼的窒息点为1.0738和1.1027 mg/L。     

胭脂鱼细胞色素b基因序列测定及亚口鱼科系统进化分析

为了解胭脂鱼(Myxocyprinus asiaticus)的遗传变异及亚口鱼(Catostomidae fish)的分子系统学,测定了3尾胭脂鱼的细胞色素b基因序列,并结合GenBank上5条亚口鱼科鱼类的相应序列一并分析。结果如下:1)共获得3尾胭脂鱼的细胞色素b基因1144 bp的一致序列,三条序列完全相同,无变异位点。2)构建的系统发育树显示,颈棱亚口鱼属(Xyrauchen texanus)和吸口鱼属(Moxostoma robustum)构成1支,胭脂鱼属(M yxocyprinus)、长背亚口鱼属(Cycleptus elongatus)和牛胭脂鱼属(Ictiobus)构成另1分支。3)自然选择检验显示,该基因在进化过程中主要受到负选择的作用。4)胭脂鱼属和牛胭脂鱼属的分歧时间最短(大约3.725百万年),颈棱亚口鱼属和长背亚口鱼属的分歧时间最长(大约5.375百万年)。     

背鳍缺失对胭脂鱼幼鱼游泳能力与反捕食能力的影响

为考察背鳍缺失对胭脂鱼( Myxocyprinus asiaticus )幼鱼游泳能力和反捕食能力的影响,将胭脂鱼幼鱼( 2.30 g±0.12 g, 4.59 cm±0.09 cm)随机分为对照组和背鳍缺失处理组(剪去背鳍),测定其临界游泳速度( U crit )及相关代谢参数、最大匀加速速度( U cat )、快速启动游泳能力以及捕食者存在条件下的存活率。结果显示:对照组和背鳍缺失组胭脂鱼幼鱼的 U crit 、最大代谢率( MMR)、 U cat 、快速启动过程的最大速度( V max )、最大加速度( A max )以及旋转角度与旋转率均无显著性差异。然而,背鳍缺失组胭脂鱼幼鱼在捕食者存在条件下的存活率显著低于对照组,背鳍缺失对胭脂鱼幼鱼的游泳能力没有明显影响,背鳍的存在可能是胭脂鱼幼鱼针对捕食者口裂限制的反捕食形态适应策略之一。