饲料中添加维生素C稀土对异育银鲫生长的影响

在基础饲料中分别添加不同剂量(0、50、100、150 mg/kg)的维生素C稀土,在室内水簇箱(50 cm×70 cm×50 cm)中进行饲养异育银鲫试验。结果表明,添加维生素C的各试验组增重率、饲料效率、蛋白质效率、鱼肉AA含量均比对照组好,但随着添加剂量的增加,增加效果呈下降趋势。以50 mg/kg的添加效果最好。     

饲料中油脂的质和量对团头鲂生长的影响

研究在饲料蛋白水平，能量水平均能满足生长需要的前提下，饲料中添加不同含量及不同品质的脂肪对团头鲂鱼种水平的影响。试验所用的精制饲料用进口酪蛋白及脂肪，糊精、维生素，矿物质、纤维素加工而成，脂肪为豆油与鳕鱼肝油。     

团头鲂对饲料中五种必需氨基酸的需要量

本文论述有关团头鲂对饲料中五种必需氨基酸需要量的试验。以鱼体蛋白氨基酸组成作为试验饲料的参考标准,用酪蛋白为基础饲料,加入不同水平的某一氨基酸及恒量的维生索、无机盐等制成颗粒饲料进行饲养试验,结果表明:团头鲂对五种必需氨基酸适宜需要量范围(克/公斤饲料),精氨酸为20.4～20.8;亮氨酸为20.2～21.7;组氨酸为6.O～6.2;赖氨酸为18.6～19.8;异亮氨酸为14.6～14.7。     

团头鲂配合饲料中锰和钴添加量的研究

试验按两因子三水平有重复试验设计，网箱养团头鲂。经９０天饲养结果表明，配合饲料中锰（Ｍｎ＾２＋）和钴（Ｃｏ＾２＋）的添加量分别为１２．９ｐｐｍ和２３．４ｐｐｍ时，团头鲂鱼种的生长效果相对最佳，饲料中添加适量的Ｃｏ＾２＋对团头鲂的生长有促进作用，且在０－２３．４ｐｐｍ范围内有递增趋势，当Ｍｎ＾２＋的添加量为２５．８ｐｐｍ时，其生长相对减慢。     

饲料中脂肪的含量对团头鲂鱼种生长的影响

本文报道了团头鲂鱼种在饲料中的蛋白质、糖、维生素和无机盐等保持适宜含量的条件下,不同脂肪含量对团头鲂鱼种生长影响的试验结果,试验所用的脂肪为新鲜的豆油。结果表明,团头鲂鱼种饲料中脂肪适宜含量为 2～5％,最适含量为3.6％左右。     

饵料中不同脂肪源对团头鲂幼鱼生长及组成的影响

团头鲂幼鱼在摄食添加不同脂肪源脂质的饵料饲养4周后，脂质添加组团头鲂体重增加快，与对照组比均有显差异；试验组鲢鱼油添加组和大豆油添加组的鱼体增重速度快，相对增重率分别为113．9％、117．9％，饵料系数分别为2．43、2．24。鲱鱼油添加组及对照组的相对增重率分别为98．1％、85．1％：饵料系数分别为2．84、2．95。鲢鱼油添加组鱼体脂质作用最好；大豆油添加组鱼体背部肌肉脂质积累较好；而鲱鱼油添加组有内脏脂质积累的表现。这说明，改变饵料的脂肪源及提高饵料中脂质含量可影响团头鲂幼鱼的生长和组成，鲢鱼油是优良的团头鲂饵料脂肪源。     

饲料中矿物质添加量对军曹鱼生长的影响

在饲料中分别添加1％、3％、5％、7％和9％的复合矿物质作试验饲料，饲养军曹鱼70天。以研究不同矿物质添加量对军曹鱼生长的影响。测定了相对增重率、饲料系数、成活率以及肥满度。结果表明，各组的成活率之间没有显著差异，但添加7％复合矿物质的组军曹鱼的相对增重率最大，饲料系数最低，肥满度也最好。各个指标显示出良好的一致实验结果。     

饲料中适量添加维生素C对虾类具有促生长作用

饲料专家研究表明：饲料中适量添加维生素C具有促长作用，过量反而抑制虾类的生长，试验表明，维生素C促进斑节对虾生长，当饲料中维生素C含量为0．06％时增重率最高，倘若维生素C含量继续升高时，对虾生长开始下降。维生素C有一个重要作用，具有促进对虾蜕皮作用，饲料中维生素C含量适量时，蜕皮率增加，生长加快；维生素C添加过多，虾类蜕皮率及生长率下降。     

无机磷、锌和复合多维对团头鲂鱼种生长影响的研究

根据团头鲂鱼种营养需要，用商品饲料原料和维生素、矿物盐等添加剂组成营养平衡的试验基础日粮。从基础日粮中分别去除添加的无机磷、锌和复合多维便构成了本次试验的三种试验日粮。试验鱼平均体重８．４３ｇ。４０天的网箱养殖试验表明，当从基础日粮中分别去除添加的无机磷、锌和复合多维后，团头鲂鱼种生长速度和饲料利用率均显著下降（Ｐ＜０．０５）。采食基础日粮、去除无机磷日粮、去除锌日粮和去除复合多维日粮的鱼，其平均增重率分别为１４７．６７％、１０８．４７％、１０６．７５％和１１６．７５％     

摄食促进物质对真鲷摄食和生长的影响

将甘氨酸 丙氨酸 组氨酸 精氨酸、甘氨酸 丙氨酸 组氨酸 精氨酸 甜菜碱、甘氨酸 丙氨酸 缬氨酸、甘氨酸 丙氨酸 缬氨酸 甜菜碱作为摄食促进物质，分别添加到真鲷配合饲料中饲喂真鲷，探讨摄食促进物质对真鲷摄食和生长的影响。结果表明，添加摄食促进物质不仅可促进真鲷的的摄食性，增加其摄食量，还可以提高真鲷的增重率、饲料效率、蛋白效率。添加甜菜碱对促进真鲷的摄食性无作用，但可促进真鲷的生长。     

团头鲂消化道发育的组织学观察

团头鲂是一种优良的淡水鱼类，为提高鱼苗饲养成活率，对其早期消化顺官的发育进行了观察。鱼苗孵出后第１天至第３天，消化道呈直管形，管壁由单列细胞组成，口裂未形成，肛管不与外界相通，营养靠自身的卵黄囊。从孵出后第３天起，口腔开始形成，消化道呈现弯曲，细胞层次增加，前肠中肠后肠三段组织学结构区分逐渐明显，卵黄囊缩小，肛门形成，可以摄取外界细小的食物。此时将鱼苗由孵化容器中移入池塘饲养比较适时，过早过晚不利     

团头鲂,鲫鱼出血性败血病的研究

最近几年,出血性败血病已成了上海地区池养鲤科鱼类的一种流行病。我们对团头鲂和鲫鱼等的这种出血性败血病作了调查并进行了综合防治试验。我们从患病的团头鲂、鲫、鲢、鳙鱼体内分离出了致病菌。对致病菌和组织病理研究所取得的材料表明,此种鱼病系由点状产气单胞菌和非霍乱孤菌所引起。根据致病菌对药物的敏感性及综合防治试验的结果,提出了一套可行的综合防治方法。     

淤泥湖团头鲂与梁子湖团头鲂杂交子一代的性状研究

团头鲂(Megalobrama amblycephala Yih)是一种优良的淡水养殖鱼类,但在家养条件下连续传代会引起经济性状指标下降。本试验通过原种选优,以优配优的杂交组合,得出淤泥湖团头鲂与梁子湖团头鲂杂交子一代和回交子代。经饲养观察,证明杂交子一代和回交子代都有良好的生长优势,含肉率和粗蛋白含量相对增高,经济性状较亲本更好。血清蛋白电泳分析结果表明,杂交子代与亲本存在着质的差异。     

团头鲂胚胎及仔稚鱼发育观察

团头鲂(Megalobrama amblycephala Yih)是鳊鲌亚科中的重要经济鱼类,现已成为国内淡水养鱼业的主要养殖对象之一。为提高团头鲂人工繁殖中的孵化出苗率和下塘成活率,本研究对其胚胎及胚后发育作了连续观察。根据形态和生态特点,作者认为当仔鱼发育至鳔雏形期就应及时下塘,孵化适温控制在18℃～27℃为宜。     

Optimizing the Proportions of Plant Protein Ingredients in the Diet of Juvenile Blunt Snout Bream,Megalobrama amblycephala

An 8‐wk feeding trial was conducted to evaluate the influence of different proportions of dietary plant ingredients on the growth of juvenile blunt snout bream, Megalobrama amblycephala. A 2 × 3 factorial arrangement was set for this trial with three ratios of cottonseed meal (CSM) and canola meal (CM) (2:1, 1:1, or 1:2) and three proportions of soybean meal (SBM) (2, 1, or 0). The results showed that the specific growth rate and protein efficiency ratio both significantly decreased with decreasing amounts of SBM in the diets of blunt snout bream (P < 0.05), while the feed efficiency ratio and feed intake increased significantly (P < 0.05). Meanwhile, the growth performance and feed utilization were shown to improve with increasing amounts of CSM, although the effects were not significant (P > 0.05). The interaction of these two factors had no effect on either growth or feed utilization (P > 0.05). Diet composition was not seen to affect body composition (P > 0.05). The ratio of CSM to CM significantly affected gut amylase activity, liver alanine aminotransferase content, and plasma cholesterol levels (P < 0.05). The interaction between the two main effects significantly influenced the plasma glucose level (P < 0.05). Therefore, the suitable proportion of plant feed for blunt snout bream should include high levels of SBM and CSM, with a SBM : CSM : CM ratio of 2:2:1.     

Dietary biotin requirement of juvenile blunt snout bream,Megalobrama amblycephala

This study was conducted to determine the optimal dietary biotin requirement of juvenile Megalobrama amblycephala. Quadruple groups of fish (initial average weight 2.01 ± 0.01 g) were fed thrice daily with six isonitrogenous and isoenergetic purified diets containing 0 (basal diet), 0.015, 0.049, 0.158, 0.624 and 2.49 mg kg^?1 biotin, respectively, for 8 weeks. Results showed that survival rate, final weight, feed intake, specific growth rate, protein efficiency ratio and nitrogen retention efficiency all increased significantly (P < 0.01) as dietary biotin levels increased from 0 to 0.049 mg kg^?1, whereas the opposite was true for feed conversion ratio. Dressout percentage, condition factor, hepatosomatic index, viscera/body ratio all showed no significant difference (P > 0.05) within the biotin range tested. Contrary to moisture content, whole‐body protein and lipid contents showed a positive correlation with dietary biotin levels. In addition, liver biotin content increased significantly (P < 0.05) with increasing dietary biotin levels up to 0.624 mg kg^?1. Hepatic pyruvate carboxylase (PC) and acetyl‐CoA carboxylase (ACC) activities both showed an increasing trend as dietary biotin levels increased. Based on the regression analysis of weight gain, hepatic PC and ACC activities, the optimal dietary biotin requirement of juvenile Megalobrama amblycephala is estimated to be 0.063, 0.071 and 0.075 mg kg^?1, respectively.     

Effects of the total fish meal replacement by soybean meal on growth parameters,serum biochemistry,and hepatic and intestinal histology of juvenile blunt snout bream (Megalobrama amblycephala)

ABSTRACT

Fish meal is the main protein source in fish diet, but due to its unsustainability, it has to be replaced with more sustainable protein sources, such as soybean meal (SBM), in fish feeds. As SBM often produces negative effects on fish growth and health, we conducted an eight-week trial of complete fish meal replacement with SBM in the diet of juvenile (48.2 ± 0.55 g) blunt snout bream (Megalobrama amblycephala), a herbivorous cyprinid fish native to the Yangtze basin (China). SBM-fed fish exhibited: a worsened growth performance; improved survival rate (P > 0.05); elevated serum triglycerides and total cholesterol but reduced low-density lipoprotein in plasma (P < 0.05); mild lipid droplet accumulation and swelling of the liver; elevated goblet cell counts and mild signs of enteritis in the intestines. With negligible effects on growth and mild effects on health, M. amblycephala appears to be comparatively tolerant of SBM, but total fish meal replacement is not recommended. Future studies should aim to identify the SBM tolerance threshold in long-term growth trials.     

Dietary isoleucine requirement of juvenile blunt snout bream,Megalobrama amblycephala

A 9‐week feeding trial was conducted to estimate the dietary isoleucine requirement of juvenile blunt snout bream. Six isonitrogenous and isoenergetic experimental diets were formulated to contain graded isoleucine levels ranging from 5.3 to 20.1 g kg^?1 dry diet. At the end of the experiment, weight gain (WG), specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) increased with increasing dietary isoleucine level up to 11.1 g kg^?1 dry diet, and dietary isoleucine level above 14.2 g kg^?1 dry diet declined these performances. Dietary isoleucine levels (14.2 and 17.3 g kg^?1 dry diet) significantly improved whole‐body protein content, but decreased whole‐body lipid, plasma triglyceride and cholesterol contents. Significantly lower visceral fat index (VFI) in fish fed with 14.2 g kg^?1 dietary isoleucine was observed compared to those fed with deficient or excessive isoleucine. Dietary isoleucine supplementation significantly increased plasma isoleucine concentration, while plasma valine and leucine concentrations showed a reversed trend. Dietary isoleucine levels regulated the target of rapamycin (TOR) gene expression and improved plasma superoxide dismutase (SOD) activity in juvenile blunt snout bream. Based on second‐order polynomial regression model analysis of SGR and FER, the optimum dietary isoleucine requirement was estimated to be 13.8 g kg^?1 dry diet (40.6 g kg^?1 dietary protein) and 14.0 g kg^?1 dry diet (41.2 g kg^?1 dietary protein), respectively.     

Dietary niacin requirement of juvenile blunt snout bream Megalobrama amblycephala based on a dose–response study

This study aimed to determine the optimal dietary niacin requirement of juvenile Megalobrama amblycephala. Fish, with an average weight of 3.62 ± 0.02 g, were randomly divided into six groups and fed six purified diets with graded levels of niacin (0, 10, 20, 30, 40 and 50 mg/kg) three times daily for 8 weeks. The survival rate, weight gain (WG), feed conversion ratio, protein efficiency and protein retention all significantly improved (p < .05) as the dietary niacin level increased from 0 to 30 mg/kg but showed no significant difference (p > .05) with further increases in niacin levels. The supplementation of 30 mg/kg niacin also led to a significant (p < .01) reduction in the viscerosomatic index, hepatosomatic index and mesenteric fat index. The dietary niacin levels exhibited minimal effects on whole‐body moisture and ash content (p > .05) but exerted a significant (p < .05) influence on protein and lipid contents and liver nicotinamide concentrations with high values obtained in fish receiving greater than 30 mg/kg of niacin. In addition, moderate levels of niacin lowered plasma triglycerides, non‐esterified fatty acid and low‐density lipoprotein cholesterol concentrations (p < .05). Based on the broken‐line regression analysis of WG and liver nicotinamide content, the optimal dietary niacin requirement of juvenile blunt snout bream was 31.25 and 30.62 mg/kg, respectively.     

Effects of dietary carbohydrate/lipid ratios on growth performance,body composition and glucose metabolism of fingerling blunt snout bream Megalobrama amblycephala

This study aimed to investigate the optimum dietary carbohydrate/lipid (CHO/L) ratio for fingerling blunt snout bream Megalobrama amblycephala (average initial weight: 6.61 ± 0.03 g). Six isonitrogenous and isoenergetic diets were formulated to contain various CHO/L ratios ranging from 1.62 to 24.20. Each diet was tested in four replicates for 10 weeks. Specific growth rate (SGR), feed conversion ratio and nitrogen and energy retention all improved significantly (P < 0.05) as dietary CHO/L ratios decreased from 24.20 to 5.64 but showed little difference (P > 0.05) as dietary CHO/L ratios ranged from 2.45 to 5.64. Hepatosomatic index increased significantly (P < 0.05) as dietary CHO/L ratios increased, whereas intraperitoneal fat ratio showed an opposite trend (P < 0.05). Opposite to moisture content, lipid content of whole body and carcass all increased significantly (P < 0.05) as dietary CHO/L ratios decreased. Liver lipid content showed little difference (P > 0.05) among all the treatments, while liver glycogen content increased significantly (P < 0.05) with increasing CHO/L ratios. High dietary carbohydrate enhanced the activities of liver hexokinase, pyruvate kinase and glucose‐6‐phosphate dehydrogenase but did not induce hyperglycaemia. Based on the second‐order polynomial regression analysis of SGR, the optimal dietary carbohydrate and lipid contents for fingerling blunt snout bream were 291.7 and 81.4 g kg⁻¹, respectively, with a corresponding dietary CHO/L ratio of 3.58.