34 ℃水温下吉富罗非鱼对饲料脂肪的需求量

为研究34 ℃水温下吉富罗非鱼对饲料脂肪的需求量，选用初始体质量为(50.88±1.57) g的吉富罗非鱼360尾，随机分成6组(每组设3个重复，每重复20尾)，饲喂脂肪含量分别为0.22%(对照组)、2.83%、4.98%、7.45%、9.23%和12.47%的6种纯化饲料，在34 ℃水温下饲养56 d后，测定并分析了吉富罗非鱼的生长性能、体成分、部分血清生化和肝脏脂肪代谢酶活性等指标。结果显示，随饲料脂肪水平升高，吉富罗非鱼增重率、特定生长率、蛋白质效率与蛋白质保留率均呈现先上升后下降的趋势，饲料系数和摄食率呈现相反的趋势；12.47%实验组肝体比显著高于其他实验组，其他指标组间无显著性差异。饲料脂肪水平对吉富罗非鱼的成活率无显著影响。对照组全鱼粗脂肪含量显著低于其他实验组；当饲料脂肪含量为7.45%~12.47%时，肌肉粗脂肪含量显著高于对照组；肝脏粗脂肪含量在饲料脂肪含量为2.83%~9.23%时较对照组显著降低。血清甘油三酯和总胆固醇随饲料脂肪水平升高呈现先下降后上升的趋势；肝脏脂肪酶和脂蛋白酯酶活性随脂肪水平的增加呈上升趋势，在12.47%组达到最大值；肝脂酶的活性呈先上升再下降最后趋于稳定的趋势，在脂肪水平为2.83%时最高, 显著高于其他各组。经回归分析，在34 ℃水温下，吉富罗非鱼要获得最佳的增重率、蛋白质效率和最低饲料系数对饲料脂肪的需求量分别为4.92%、5.67%和6.49%。     

饲料脂肪水平对白甲鱼幼鱼消化酶活性的影响

为评价不同饲料脂肪水平对白甲鱼(Onychostoma simus)幼鱼消化酶活性的影响,以豆油为脂肪源,分别以6种脂肪水平(2.83%、4.52%、6.68%、9.14%、11.35%、14.07%)的试验饲料养殖初始均质量(0.78±0.05)g的白甲鱼60 d。结果表明:随着饲料脂肪水平的升高,肠蛋白酶活性均呈下降趋势,但当饲料脂肪水平≥9.14%时差异不显著(P>0.05);肝胰脏蛋白酶活性在饲料脂肪水平<9.14%时无明显变化(P>0.05),脂肪水平>9.14%时显著降低(P<0.05);肠脂肪酶活性随着饲料脂肪水平的升高呈上升趋势;肝胰脏脂肪酶活性随饲料脂肪水平的升高呈先升后降的变化趋势,饲料脂肪水平≥11.35%时,肝胰脏脂肪酶活性显著降低(P<0.05),前肠淀粉酶活性无明显变化(P>0.05),中肠淀粉酶活性呈先升后降的变化趋势,后肠淀粉酶活性则略有下降(P>0.05),肝胰脏淀粉酶活性则呈先升后降的变化趋势,但差异不明显(P>0.05)。研究表明,适宜的饲料脂肪水平能改善白甲鱼幼鱼消化酶的活性,提高对饲料营养物质的消化利用率。     

饲料糖水平对吉富罗非鱼幼鱼生长和肝代谢功能的影响

为研究饲料糖水平对吉富罗非鱼幼鱼生长性能和肝代谢功能的影响,实验配制等蛋白、等脂肪含量的8种不同糖水平(10％、15％、20％、25％、30％、35％、40％和45％)饲料,每个糖水平设3个重复,饲养周期49 d,结果显示:(1)饲料糖水平对吉富罗非鱼幼鱼的增重率、成活率、饲料系数和肝体比均有显著影响(P＜0.05).饲料糖水平为35％时,罗非鱼增重最快;饲料糖水平为40％时饲料系数最低.(2)随着饲料糖水平的升高,鱼体肌糖原、粗脂肪含量逐渐升高,鱼体肝糖原含量先增加后下降.(3)饲料糖水平对各组鱼血清谷草转氨酶、谷丙转氨酶、血清磷酸果糖激酶活性、总蛋白和总胆汁酸浓度均有显著影响(P＜0.05),且随着糖水平的升高,呈上升趋势;而鱼体肝酯酶和脂蛋白脂酶活性则是先上升后下降.(4)饲料糖水平35％时,肝脏组织出现少量细胞脂滴空泡状现象;饲料糖水平40％和45％时,肝脏组织切片有明显的细胞脂滴空泡状、核偏移和细胞质消失现象.肝脏脂滴空泡状面积率与组织脂肪含量具有显著的正相关,与肝脏组织的脂肪肝病变程度成正比.结果表明,吉富罗非鱼苗种饲料以29.10％～ 35.00％的糖水平较利于吉富罗非鱼幼鱼生长及后期的脂肪肝病预防.     

饲料脂肪水平对克氏原螯虾亲虾生长性能、肌肉成分、繁殖性能以及血淋巴生化指标的影响

为研究克氏原螯虾亲虾对脂肪的需要量,本实验采用初始体质量为(15.46±0.20)g的克氏原螯虾亲虾324尾,分为6组(每组设置3个重复,每个重复18尾,雌雄比例为2:1),投喂粗蛋白质水平为30%,脂肪水平分别为1.98%(对照组)、4.12%、5.84%、7.89%、10.48%和11.89%的6组半精制饲料,饲养8周后,测定并分析亲虾的生长性能、肌肉成分、繁殖性能、肝胰腺消化酶活性以及血淋巴部分生化指标。结果发现:①随着饲料脂肪水平的升高,增重率和特定生长率先上升,在饲料脂肪水平达到7.89%后呈下降趋势;饲料系数和肝体比呈上升趋势,11.89%组最高。②饲料脂肪水平对亲虾肌肉水分和灰分含量无显著影响;随着饲料脂肪水平的升高,肌肉粗脂肪含量呈现先升高后降低最后趋于稳定的趋势,在饲料脂肪水平为5.84%时最高。③随着饲料脂肪水平的升高,性腺指数、抱卵率、抱卵量均呈现先上升后降低的变化规律,均在饲料脂肪水平为7.89%时达到最大。④血淋巴中总蛋白含量随饲料脂肪水平呈现先下降后上升趋势;谷草转氨酶、谷丙转氨酶活性均随饲料脂肪水平升高而升高,均在11.89%组最高;血淋巴中葡萄糖含量各组间无显著性差异。⑤饲料脂肪水平对实验虾肝胰腺蛋白酶和脂肪酶活性有显著影响,对淀粉酶活性无显著性影响。利用增重率与饲料脂肪水平进行折线回归分析,克氏原螯虾亲虾获得最佳增重率时对饲料的脂肪需要量为7.60%。对实验虾生长性能、肌肉成分、繁殖性能、肝胰腺消化酶活性、血淋巴生化指标进行综合分析,显示本实验条件下克氏原螯虾亲虾对脂肪需要量为7.60%～7.89%。     

饲料脂肪水平对白甲鱼幼鱼形体指数、脂肪沉积和脂肪代谢酶活性的影响

实验评价了不同饲料脂肪水平对白甲鱼形体指数、脂肪沉积和脂肪代谢酶活性的影响。选用初始均质量(0.78±0.05)g的白甲鱼幼鱼900尾,随机分成6个实验组,每组3个重复,每个重复50尾实验鱼,分别饲喂添加0%(对照组)、2%、4%、6%、8%和10%的豆油,设计出脂肪水平为2.83%、4.52%、6.68%、9.14%、11.35%和14.07%的6种等氮(蛋白质含量为40%)等能(总能为16.30 MJ/kg)的实验饲料,养殖时间为60 d。结果表明,随着饲料脂肪水平的升高,白甲鱼幼鱼肥满度(CF)先升后降的变化趋势,且脂肪水平为9.14%时最大,为2.64%,但饲料脂肪水平为6.68%～14.07%时差异不显著(P>0.05),肝体指数(HSI)随饲料脂肪水平的升高呈上升趋势,脏体指数(VSI)则随饲料脂肪水平的升高呈略微上升趋势(P>0.05);白甲鱼幼鱼肌肉和肝脏中脂肪的含量易受饲料脂肪水平的影响。随着饲料脂肪水平的升高,肌肉和肝脏脂肪含量均呈上升趋势,饲料脂肪水平对饲料氮的沉积量无明显影响(P>0.05),能量沉积量则在饲料脂肪水平为14.07%时最高,氮和能量的沉积率随饲料脂肪水平的升高呈先升后降的变化趋势,且分别在饲料脂肪水平为11.35%和9.14%时达到最大,脂肪的沉积量随饲料脂肪水平的升高而升高,但脂肪沉积率则随饲料脂肪水平的升高而逐渐降低(P<0.05);白甲鱼幼鱼肠道脂肪酶活性呈先升后降的变化趋势,且在脂肪水平为9.14%时最大,为296.03 U/g,脂蛋白酯酶、肝脂酶和总酯酶活性则呈先升后降并逐渐趋于稳定,均在饲料脂肪水平为9.14%时达到最高;脂肪合成酶则呈逐渐降低的趋势(P<0.05)。说明适当的饲料脂肪水平可以提高饲料营养物质的利用率,但过高的脂肪水平(11.35%及以上)将使白甲鱼肝脏脂肪沉积增多,不利于鱼类健康生长。     

团头鲂两个生长阶段适宜蛋白/脂肪比的需要量

为了在相同配方体系下研究团头鲂两个生长阶段对饲料中蛋白/脂肪比的需要量,以初均重为(35.07±0.45)g(幼鱼)、(101.65±1.82)g(育成鱼)两个阶段的团头鲂为实验鱼,以秘鲁鱼粉、酪蛋白、大豆磷脂、豆油等原料配制半纯化饲料,在蛋白质26.93%~35.63%、脂肪10.24%~3.35%范围内,设置蛋白/脂肪比浓度分别为2.63、3.20、4.07、5.33、7.25和10.64共6组饲料。分别在池塘网箱养殖85和56 d,每组实验鱼设置4个平行。结果发现,随着饲料蛋白/脂肪比水平的增加,两个阶段的团头鲂体质量特定生长率(SGR)、蛋白质沉积率(PDR)、能量保留率(ERR)总体均呈现先上升后下降的趋势,均在饲料蛋白/脂肪比为5.33组达到最高;饲料系数(FCR)则呈先下降后上升的趋势,且均在饲料蛋白/脂肪比为5.33组达到最低。分别以实验鱼特定生长率(SGR)、饲料系数(FCR)、蛋白质沉积率(PDR)及能量保留率(ERR)作为评价指标,经过回归分析可知,幼鱼阶段团头鲂对饲料中蛋白/脂肪比需要量为6.09~7.58,适宜蛋白质水平为32.83%~33.98%、脂肪水平为4.48%~5.39%;在日均摄食量为5.06 g/100 g体质量的条件下,团头鲂幼鱼对饲料蛋白质每日需要量为1.66~1.72 g/100 g体质量,对饲料脂肪每日需要量为0.23~0.27 g/100 g体质量。育成鱼阶段团头鲂对饲料中蛋白/脂肪比需要量为4.03~4.34,适宜蛋白质水平为30.19%~30.72%、脂肪水平为7.07%~7.49%。在日均摄食量为3.61 g/100 g体质量的条件下,团头鲂育成鱼对饲料蛋白质每日需要量为1.09~1.11 g/100 g体质量,对饲料脂肪每日需要量为0.26~0.27 g/100 g体质量。     

饲料中添加水飞蓟素对吉富罗非鱼生长性能、肝脏脂肪代谢酶和抗氧化能力的影响

为评估饲料中添加水飞蓟素对吉富罗非鱼生长性能、肝脏脂肪代谢酶和抗氧化能力的影响,分别在5组等氮等能的吉富罗非鱼饲料中添加不同水平的水飞蓟素[0(对照组)、100、200、400和800 mg/kg],饲喂初始体质量为(8.17±0.31)g的吉富罗非鱼幼鱼9周,测定实验鱼的生长性能、血清生化指标、肝脏脂肪代谢酶活性及抗氧化酶活性。结果显示,随饲料中水飞蓟素添加水平增加,吉富罗非鱼终末体质量、增重率、特定生长率和肥满度均呈先增加后降低的趋势,各指标均在100mg/kg实验组达到最大,100mg/kg实验组的饲料系数显著低于对照组。饲料中添加水飞蓟素显著降低了实验鱼肝体比和脏体比。100mg/kg实验组全鱼、肌肉和肝脏的粗脂肪含量显著低于对照组。血清谷草转氨酶和谷丙转氨酶活性随水飞蓟素水平增加呈先降低后升高的趋势,分别在200和100 mg/kg实验组达到最低,两组之间无显著性差异。饲料中添加水飞蓟素后,血清中的甘油三酯含量显著低于对照组;肝脏中的脂蛋白脂酶和总酯酶活性显著高于对照组;肝脏脂肪酶活性呈先上升后降低趋势,在200 mg/kg实验组最高,且与对照组有显著性差异。饲料中添加水飞蓟素后,肝脏谷胱甘肽过氧化物酶活性显著高于对照组,肝脏过氧化氢酶活性显著低于对照组;肝脏丙二醛含量显著低于对照组。100 mg/kg实验组罗非鱼的肝细胞界限清晰,无核偏移,空泡较少。研究表明,饲料中添加适量水飞蓟素提高了吉富罗非鱼生长性能,调节了肝脏脂肪代谢酶活性和抗氧化能力,对防治肝脏细胞损伤有积极作用。在本实验条件下,推荐吉富罗非鱼幼鱼饲料中水飞蓟素添加水平为100 mg/kg。     

饲料脂肪水平对俄罗斯鲟幼鱼生长、血液生化指标及抗氧化性能的影响

以鱼油、豆油、亚麻籽油等比例混合,配成脂肪含量分别为5.45%(L1)、7.00%(L2)、10.44%(L3)、14.37%(L4)、16.34%(L5)、18.91%(L6)及20.15%(L7)的等氮饲料,饲喂俄罗斯鲟(Acipenser gueldenstaedtii)幼鱼[(6.20±0.02)g]8周。实验结果表明,L3组的终末体质量、增重率最大,但与L2组间无显著差异(P0.05),L3组的蛋白质效率显著高于其它组(P0.05),且饲料系数最低。L6和L7组终末体质量、增重率和蛋白质效率显著低于L2和L3组(P0.05)。将幼鱼的增重率与饲料脂肪水平进行回归分析,得出俄罗斯鲟幼鱼在饲料脂肪水平为10.69%时生长最佳。随着饲料脂肪水平的升高,各组鱼的肝体比和体粗脂肪有上升趋势,其中肝体比在饲料脂肪含量大于14.37%时显著增大(P0.05)。血清中的甘油三酯、胆固醇含量也随脂肪水平升高而显著提高(P0.05),提示脂肪过高会影响俄罗斯鲟幼鱼的生长,降低蛋白质效率,导致脂肪在体内的过量积蓄。L7组鱼血清中高密度脂蛋白胆固醇含量最高,而L1组鱼的低密度脂蛋白胆固醇含量最高。肝脏脂蛋白酯酶活性随饲料脂肪水平的提高而升高,脂肪酸合成酶活性则随脂肪水平升高而降低,提示饲料脂肪水平的提高会促进鱼体脂肪的分解代谢。肝脏丙二醛含量和超氧化物歧化酶活性均随着饲料脂肪水平的提高显著升高(P0.05),表明脂肪含量过高会导致脂质过氧化,引发机体抗氧化酶活性的升高。综合俄罗斯鲟幼鱼的生长、血液指标及抗氧化性能,建议生产中将幼鱼的饲料脂肪水平控制在7.00%~10.69%。     

饲料蛋白水平对台湾泥鳅幼鱼生长、饲料利用率及免疫酶活性的影响

本研究旨在评价饲料蛋白水平对台湾泥鳅(Paramisgumus dabryanus ssp)幼鱼生长性能、饲料利用率及免疫酶活性的影响。选用初始体重为(8.57±0.35)g的台湾泥鳅720尾,随机分成4组,每组设置3个重复,每个重复60尾鱼,分别投喂蛋白水平为25%、30%、35%和40%的实验饲料,养殖时间为60 d。结果显示,随着饲料蛋白水平的升高,台湾泥鳅幼鱼末重(FW)、特定生长率(SGR)和饲料效率(FER)先上升,饲料蛋白水平≥35%后,进入平台期。蛋白质效率(PER)、蛋白质沉积率(PRE)和成活率(SR)均呈先升高后降低的变化趋势。摄食率(FR)则呈逐渐降低的趋势。基于FW、SGR和FER的折线模拟结果表明,台湾泥鳅幼鱼达到最佳生长速度及饲料效率的饲料蛋白水平为34.57%~35.37%。通过二次多项式回归分析可知,台湾泥鳅幼鱼蛋白利用率最高时的饲料蛋白水平为33.61%~34.68%。随着饲料蛋白水平的升高,台湾泥鳅幼鱼超氧化物歧化酶(SOD)活性呈先升高后趋于稳定的变化趋势,过氧化氢酶(CAT)活性呈先升高后降低的变化趋势;谷丙转氨酶(GPT)和谷草转氨酶(GOT)均呈先升高后降低的变化趋势。由此得出,适宜的饲料蛋白水平可促进台湾泥鳅幼鱼的生长,提高饲料效率,增强免疫酶活性。在本实验条件下,综合考虑生长性能、饲料利用率及免疫酶活性,台湾泥鳅幼鱼饲料最适蛋白水平为34.68%~35.37%。     

杂交鲟幼鱼饲料中有效磷需要量的研究

为研究杂交鲟(Acipenser baerii♀×Acipenser schrenckii♂)幼鱼对饲料中有效磷的需要量,实验以磷酸二氢钙为磷源,配制了有效磷水平分别为0.37%(对照组)、0.65%、0.96%、1.22%和1.48%的5组等氮等能饲料。每组饲料设置3个重复,每个重复22尾鱼,饲喂初重(10.06±0.39)g杂交鲟幼鱼8周。结果显示:(1)饲料中不同有效磷水平对实验鱼的成活率、肝体比、脏体比和肥满度均无显著影响。随饲料有效磷水平增加,实验鱼的增重率和特定生长率呈先升高后趋于平稳的趋势,0.96%、1.22%和1.48%组增重率和特定生长率均显著高于0.37%组和0.65%组;全鱼粗脂肪含量呈降低趋势;饲料效率和蛋白质效率均呈先升高后降低的趋势。(2)不同有效磷水平饲料对全鱼水分、粗蛋白和肌肉水分、粗蛋白、粗脂肪、粗灰分、磷含量均无显著影响。0.96%、1.22%和1.48%组全鱼粗灰分、磷含量和脊椎粗灰分、磷含量均显著高于0.37%组和0.65%组。(3)随饲料有效磷水平增加,实验鱼血清磷含量和碱性磷酸酶活性均呈先升高后趋于平稳的趋势。0.96%、1.22%和1.48%组血清磷含量显著高于0.37%组和0.65%组,对照组的碱性磷酸酶活性显著低于其他组。(4)分别利用折线模型拟合分析实验鱼的增重率、全鱼磷含量和脊椎磷含量与饲料有效磷水平的相关性,得到饲料中适宜有效磷需要量分别为0.93%、1.02%和0.95%。综上所述,建议杂交鲟幼鱼饲料中有效磷添加水平为0.93%~1.02%为最佳。     

Influence of Ulva meal on growth, feed utilization, and body composition of juvenile Nile tilapia (Oreochromis niloticus) at two levels of dietary lipid

A nutrition trial was conducted to investigate the effects of dietary lipid levels and supplemental Ulva meal on growth performance, feed efficiency, nutrient utilization, and body composition of juvenile Nile tilapia, Oreochromis niloticus. Four isonitrogenous (CP 40%) diets containing 0% and 5% Ulva meal were formulated to contain 10% (low-lipid; LL) and 20% (high-lipid; HL) crude lipid. Triplicate groups of fish (~10 g) were fed to apparent satiation three times daily for 16 weeks. Fish fed 5% Ulva meal showed an increased growth performance (P < 0.05) compared with fish fed non-Ulva supplemented diets, irrespective of dietary lipid level. In particular, the incorporation of Ulva meal improved specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER). Feeding fish 5% Ulva meal diets resulted in significantly lower carcass lipid content. The results indicate that 5% inclusion of Ulva meal at both dietary lipid levels improves growth performance, feed efficiency, nutrient utilization, and body composition of Nile tilapia.     

Effects of dietary protein on growth and body composition of Nile tilapia, Oreochromis niloticus L.

The effects of dietary protein (25%, 30%, 35%, 40% and 45%) on growth, survival, feed conversion ratio (FCR), protein efficiency ratio (PER) and body composition were investigated for four sizes (0.51, 45, 96 and 264 g) of Nile tilapia, Oreochromis niloticus L. In all four experiments, there was a progressive increase in growth with increasing dietary protein. In fry (0.51 g), significantly higher growth, survival and feed conversion were recorded for fish fed 40–45% rather than 25–35% protein diets. Similar trends for growth and FCR were also noted in 45 g fish. For larger (96 and 264 g) tilapia, significant differences in growth and FCR were found only between fish fed 25% and 30–45% protein diets. FCR and PER decreased with increasing weight of fish, and both were found to be negatively correlated with dietary protein level. Whole-body composition of the smallest fish was significantly influenced by dietary protein content. Percentage body protein of the fish fed 40–45% protein was higher than that of fish fed 25–35% protein diets, whereas lipid content decreased with increasing dietary protein level. In 45 g fish, both protein and lipid contents were higher in fish fed 25% and 30% protein diets than in those fed 35–45% protein diets. In larger tilapia, no significant influence of dietary protein level on body protein content was found. Percentage lipid decreased with increasing dietary protein level, and no definite trends in ash content were found. The results of these studies indicate that O. niloticus fry (0.51 g) should be reared on a practical diet containing 40% protein, and larger tilapia (96–264 g) on a diet containing 30% protein.     

Dietary phosphorus requirement for juvenile bighead carp (Aristichthys nobilis)

A 60-day feeding trial was conducted to estimate the optimum phosphorus requirement of juvenile bighead carp (Aristichthys nobilis). Fish (initial body weight: 2.42?±?0.08 g) were hand-fed with six isoproteic (437 g kg^?1) and isolipidic (68 g kg^?1) diets containing graded phosphorus levels (0.90, 4.40, 8.30, 11.90, 15.50, and 19.30 g kg^?1) thrice daily to apparent satiation. Each diet was randomly assigned to triplicate tanks, and each tank was stocked with 30 fish. The highest weight gain rate (WGR, 288.94%) and specific growth rate (2.28% day^?1) and the best feed conversion rate (FCR, 1.91) were recorded in fish fed 8.30 g kg^?1 phosphorus. The body composition analysis showed that the phosphorus contents in the whole body, muscle, vertebra, and plasma of fish fed the phosphorus-supplemented diets were higher than those of fish fed the control diet, whereas the phosphorus retention rate and crude lipid contents in the whole body and muscle presented the reverse results. The highest activity of lipase (41.97 U g^?1 prot) in the intestine was found in fish fed the diet with 11.90 g kg^?1 phosphorus. Further, the contents of total protein, albumin, and globulin in plasma were increased as dietary phosphorus levels ranged from 0.90 to 11.90 g kg^?1 and then decreased with further increased phosphorus levels. The highest contents of triglyceride (1.85 mmol L^?1) and total cholesterol (2.16 mmol L^?1) in plasma occurred at dietary phosphorus level of 0.90 g kg^?1. Broken-line model analysis based on WGR, FCR, and the phosphorus contents of the whole body and vertebra indicated that the optimal phosphorus requirements for juvenile bighead carp were 7.16, 9.02, 10.88, and 11.04 g kg^?1, respectively.

     

Effects of dietary protein and lipid content on growth performance and biological indices of iridescent Shark (Pangasius hypophthalmus, Sauvage 1878) fry

Dietary protein and lipid effects on growth, body composition and indices of iridescent Shark Pangasius hypophthalmus (Sauvage 1878) fry were studied using a 4 × 2 factorial design. Triplicate groups of 10 fish per tank, with initial mean weights of 3.54–3.85 g were fed eight isocaloric diets comprising a combination of four protein levels (250, 300, 350 and 400 g kg⁻¹ or 25%, 30%, 35% and 40%) and two lipid levels (60 and 120 g kg⁻¹ or 6% and 12%) respectively. The fish were hand-fed to satiety twice daily for 8 weeks. Specific growth rate (SGR) and feed conversion ratio (FCR) showed significant effects ( P <0.05) with variations in dietary protein and lipid. The highest SGR was observed in fish fed 40% protein/12% lipid diet but this value was not significantly ( P >0.05) different from the fish fed 30% protein/12% lipid diet. The FCR was lowest for the 40/12 diet and differed significantly only with the 25/6, 25/12 and 30/6 treatments respectively. The hepatosomatic index (HSI) was significantly affected by the level of protein, but intraperitoneal fat (IPF) showed significant variation due to dietary lipid level. The HSI significantly ( P <0.05) decreased when dietary protein increased from 25% to 30% but increased marginally thereafter. The IPF values increased with increased dietary lipid but decreased with increased dietary protein. Body protein was positively correlated with dietary protein content; conversely, body lipid content decreased with increase in dietary protein. The results of this experiment indicate the presence of a protein-sparing effect of lipid as fish fed 30% protein/12% lipid diet had growth and feed utilization comparable to those fed 40% protein/12% lipid diet.     

饲料中豆粕替代鱼粉比例对牙鲆生长性能及生化指标的影响

以鱼粉和豆粕分别为主要动物性和植物性蛋白源,研究饲料中不同豆粕替代鱼粉比例对牙鲆幼鱼生长性能和生化指标的影响。设计4∶1、3∶1、2∶1和1∶1四种不同动植物蛋白比的等氮等脂饲料配方,按配方制备试验饲料,分别表示为D1、D2、D3和D4。牙鲆幼鱼随机分配到12个设有循环水系统的玻璃钢桶内(900L),每3桶鱼饲喂一种饲料,每天投喂饲料2次,每次达到表观饱食,饲喂期为56d。以增重率(WGR)、饵料系数(FCR)、特定生长率(SGR)、蛋白质效率(PER)、肝体指数(HSI)、肥满度(CF)、鱼体成分和饲料成本为依据,综合评价饲料中不同比例的豆粕替代鱼粉比例对牙鲆的饲养效果。通过测定尿素氮(BUN)、谷丙转氨酶(GPT)、谷草转氨酶(GOT)、游离脂肪酸(FFA)、总蛋白(TP)、甘油三酯(TG)、胆固醇(CHO)、高密度脂蛋白胆固醇(HDL-C)及低密度脂蛋白胆固醇(LDL-C)等生化指标,研究饲料中不同豆粕替代鱼粉比例对牙鲆蛋白质代谢和脂肪代谢的影响。随豆粕比例的增加,WGR、PER和SGR逐渐降低,FCR逐渐增加,当饲料中豆粕比例在24%以上时差异显著(P<0.05);HSI逐渐增加,且D1组显著低于其他...     

饲料中添加L-肉碱对吉富罗非鱼生长、肝脏脂肪代谢及抗氧化能力的影响

分别在3组等氮等能的吉富罗非鱼(GIFT,Oreochromis niloticus)饲料中添加不同水平的L-肉碱[0(对照组)、150和300 mg/kg],试验选用初始体重为(8.21±0.33)g的幼鱼投喂9周,探讨L-肉碱对吉富罗非鱼生长、体成分、血清生化指标、肝脏脂肪代谢酶活性和抗氧化能力的影响。结果表明:添加150或300 mg/kg L-肉碱显著提高了罗非鱼增重率(WGR)和特定生长率(SGR),显著降低了实验鱼肝体比(HSI)和脏体比(VSI);添加150 mg/kg L-肉碱组WGR和SGR最高,HSI和VSI最低。添加150 mg/kg L-肉碱显著提高了鱼体肥满度(CF)。饲料系数(FCR)和存活率(SR)在对照组和实验组间无显著差异。添加150或300 mg/kg L-肉碱显著提高了鱼体肝脏中粗蛋白含量,添加150 mg/kg L-肉碱显著降低了肝脏粗脂肪含量。添加150或300 mg/kg L-肉碱时,血清甘油三酯(TG)含量显著降低,肝脏脂蛋白脂酶(LPL)、肝脂酶(HL)、总酯酶(LPL)和脂肪酶(LPS)活性显著上升,肝脏过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-PX)活性显著增加,肝脏丙二醛(MDA)含量显著下降。添加300 mg/kg L-肉碱显著提高了鱼体肝脏超氧化物歧化酶(SOD)活性和溶菌酶(LZM)活性。综上,饲料中添加适量L-肉碱对提高吉富罗非鱼生长性能,促进其脂肪代谢和提高鱼体抗氧化能力有良好效果。基于L-肉碱对罗非鱼增重率和特定生长率的影响,推荐L-肉碱在吉富罗非鱼饲料中的添加量为150 mg/kg。     

实用饲料添加肌醇对草鱼生长、脂质代谢及抗氧化机能的影响

为探讨肌醇对草鱼生长、脂质代谢及抗氧化机能的影响,以实用饲料配方为基础,分别添加0(对照)、50、100、150、200、300和400 mg/kg肌醇,配制成7组等氮等脂的饲料,每组饲料设4个重复,每个重复饲喂初始体质量为(15.00±0.15)g的草鱼25尾,养殖56 d。结果显示,饲料中添加100~150 mg/kg肌醇能显著提高草鱼终末均重(FBW)、增重率(WGR)、特定生长率(SGR)及饲料效率(FE);随饲料肌醇添加水平的上升,全鱼脂肪、肝脏脂肪和脂肪沉积率先升后降,在50~300 mg/kg均与对照组存在显著差异,且均在100 mg/kg达到最大值。肌肉脂肪则逐渐下降并趋于稳定,在100 mg/kg达到最小值,100~400 mg/kg差异不显著;肠脂肪酶、血浆总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)含量及高密度/低密度脂蛋白胆固醇(HDL-C/LDL-C)均呈先升后降的趋势,除LDL-C在各组间差异不显著外,其余指标均在100~150 mg/kg达到最大值;添加肌醇能显著增强肝脏和肌肉中肉碱脂酰转移酶(CPT-I)和乙酰辅酶A羧化酶(ACC)的活性。与对照组相比,100 mg/kg肝脏CPT-I的增幅比例低于ACC的增幅比例,肌肉则相反;当肌醇添加水平为100~150 mg/kg时,肝脏和肌肉中超氧化物歧化酶(SOD)的活性显著升高,丙二醛(MDA)含量及血浆中谷丙转氨酶(ALT)、谷草转氨酶(AST)均显著降低。研究表明,实用饲料添加适宜的肌醇能改善草鱼的生长、饲料转化和肝脏功能,促进脂肪消化,加快脂肪酸的合成与分解代谢,使全鱼和肝脏增脂、肌肉降脂,且能够提高肝脏和肌肉的抗氧化机能。以FE和SGR为效应指标,草鱼实用饲料肌醇适宜添加量为90.3~96.4 mg/kg。     

饲料蛋白质和能量水平对红姑鱼生长和鱼体组成的影响

采用 3× 3因子试验确定不同蛋白质和脂肪水平实用饲料对红姑鱼生长和鱼体组成的影响。初始平均体重为 2 .73g的试验鱼放养在 2 7个 2 .5m× 1.5m× 1.3m的网箱中 ,每箱放养 6 0尾。用饲料蛋白质水平为38% ,42 %和 46 % ,脂肪水平为 5 % ,8%和 12 %的试验饲料饲养鱼 8周。结果表明特定生长率和饲料系数以高蛋白质组 (HP ,46 % )显著高于中蛋白组 (MP ,42 % )和低蛋白组 (LP ,38% ) (P <0 .0 5 ) ;饲料脂肪水平对鱼的生长和饲料系数没有显著影响 (P >0 .0 5 ) ;随饲料DP/DE降低 ,脏体比和肝体比增加 ;随饲料可消化能增加 ,全鱼和肝脏的脂肪含量增加 ,但对机体的蛋白含量、氨基酸构成和灰分含量没有多大的影响。从本试验可初步认为红姑鱼幼鱼最适饲料蛋白质水平为 46 % ,可消化蛋能比 (DP/DE)为 119mg·kcal-1。     

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)。     

Effect of partial fish meal replacement by soybean meal on the growth performance and biochemical indices of juvenile Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

A feeding trial was conducted to investigate the effect of partial fish meal (FM) replacement by dietary soybean meal (SBM) on the growth and protein and lipid metabolism of the juvenile Japanese flounder. Four isonitrogenous and isolipidic diets (Diets 1–4) were formulated containing 47% protein and 9% lipid with different SBM inclusion (Diet 1, 11%; Diet 2, 16%; Diet 3, 24%; and Diet 4, 41%). The fish were fed to satiation twice daily for a feeding period of 56 days. The weight gain rate (WGR) and protein efficiency ratio of fish fed Diet 4 were significantly lower than those fed Diets 1, 2, and 3, and feed conversion ratio in the group fed Diet 4 was significantly higher than that in the groups fed Diets 1, 2, and 3. Hepatosomatic indices showed the similar trend as WGR, and the value (1.75%) for Diet 1 was significantly lower than that (1.96–2.2%) for other diets. There were no differences in whole body moisture, crude protein, crude lipid, and ash content among all treatments. With increasing dietary SBM level, serum triglyceride (TG), cholesterol (CHO), and low-density lipoprotein cholesterol (LDL-C) concentrations increased, whereas the serum total protein (TP) and high-density lipoprotein cholesterol (HDL-C) concentrations decreased. Compared with Diet 1, the serum TG, CHO, and LDL-C concentrations of fish fed Diet 4 significantly increased by 78, 37, and 36%, respectively, while the TP and HDL-C concentrations decreased by 14 and 33%, respectively. No significant differences in condition factor, blood urea nitrogen concentration, and alanine and aspartate aminotransferase activities were observed among the dietary treatments. These results indicated that dietary SBM inclusion above 24% could adversely affect the growth and protein and lipid metabolism of Japanese flounder.