木薯粉在罗非鱼饵料中的适口性研究

选择健康的吉富罗非鱼为试验鱼,比较不同水平木薯粉之间的诱食效果以及木薯粉与豆粕、次粉的适口性,评价木薯粉在罗非鱼饵料中的应用效果。结果表明,(1)40%、30%木薯粉组的诱食活性显著高于10%、20%木薯粉组(p0.01),40%与30%木薯粉之间没有显著差异(p0.05)。(2)罗非鱼对木薯粉与豆粕、次粉的适口性依次为豆粕木薯次粉。     

饲料中添加中性蛋白酶对吉富罗非鱼生长和消化功能的影响

在吉富罗非鱼(Oreochromis niloticus)基础饲料中添加中性蛋白酶,添加量分别为0.00%、0.05%、0.1%、0.15%、0.2%和0.25%,研究添加后对吉富罗非鱼生长和消化功能的影响。结果表明,在饲料中添加0.1%~0.25%的中性蛋白酶,吉富罗非鱼的相对增重率和特定生长率显著提高,饲料系数显著降低(P<0.05);添加0.1%~0.2%的中性蛋白酶,显著提高饲料干物质表观消化率和粗蛋白表观消化率(P<0.05);添加量为0.1%~0.15%时,肝胰脏蛋白酶显著高于对照组(P<0.05),添加量为0.15%时,肠道蛋白酶活性显著提高(P<0.05)。综合鱼体相对增重率、特定生长率、饲料系数、消化器官消化酶活性等各项指标,吉富罗非鱼饲料中中性蛋白酶的添加量以饲料的0.1%~0.2%为宜。     

不同蛋白水平的饲料对圆斑星鲽生长受表观消化率的影响

以鱼粉和酪蛋白为蛋白源,鱼油和豆油为脂肪源,配制成脂肪水平为8％,蛋白水平各为40％、45％、50％的三组饲料（分别表示为A、B、C组）,分别对平均规格为（93．0±1．0）g的圆斑星鲽进行投饲。经过10周的饲养实验,结果表明：鱼体的生长受饲料中蛋白水平的影响显著,鱼体增重率随饲料中蛋白水平的升高而逐渐升高,饲料系数则随之降低。饲料中营养物质的表观消化率随饲料中蛋白水平的升高有升高的趋势,以C组的表观消化率最高,且显著高于A组。由此可见,饲料蛋白水平在50％时,圆斑星鲽的生长及对营养物质的吸收利用效果最好。     

高糖饲料对吉富罗非鱼生长性能、饲料利用和糖脂代谢的影响

为探讨高糖饲料对吉富罗非鱼(GIFT Oreochromis niloticus)生长性能、饲料利用和糖脂代谢的影响,设置糖水平为34%的对照饲料(C组,能量水平13.68 k J·g-1)、糖水平为48%的高糖高能饲料(HCE组,能量水平16.03 k J·g-1)和高糖等能饲料(HE组,能量水平13.81 k J·g-1),在室内循环水系统中饲养初始体质量(20.34±0.42)g的吉富罗非鱼幼鱼60 d。结果表明,HCE组和HE组的增重率、特定生长率、肝脏粗蛋白均显著低于C组(P0.05),饲料系数、肝脏粗脂肪、肝糖原、总糖表观消化率、血清低密度脂蛋白胆固醇和高密度脂蛋白胆固醇均显著高于C组(P0.05);HE组增重率、全鱼粗脂肪、血清甘油三酯和总胆固醇均显著低于HCE组(P0.05);高糖组肝脏葡萄糖激酶显著高于C组,HE组葡萄糖-6-磷酸脱氢酶、苹果酸酶、脂肪酸合成酶活性最高,C组最低(P0.05);由肝脏组织切片看出,高糖饲料引起吉富罗非鱼肝脏细胞肿大变形,出现空泡,HCE组对肝脏损伤更加显著。研究结果表明,吉富罗非鱼能够耐受48%糖水平的饲料,但长期摄食导致鱼体糖脂代谢紊乱,尤其影响脂肪代谢,造成鱼体脂肪蓄积,肝功能损伤,不利于生长与健康。     

饲料中木薯粉替代面粉对凡纳滨对虾生长、饲料利用的影响

木薯粉,又称泰国生粉,是一类从树薯或木薯植物的根部精炼出来的淀粉。由于价格较为便宜,近年来,许多国家研究用木薯作为畜禽饲料以补充饲料原料的不足,我国用木薯替代玉米、面粉饲料原料等饲养畜禽取得良好效果。     

氧化三甲胺对罗非鱼幼鱼生长及饲料利用的影响

采用单因素梯度设计,在饲料中添加50、100、200和1 000 mg/kg氧化三甲胺,饲养体重3.5g左右的罗非鱼8周.结果显示,在配合饲料中添加50～200 mg/kg氧化三甲胺对罗非鱼具有明显的促生长作用,其增重量、增重率显著高于对照组,饲料系数显著低于对照组,饲料效率和蛋白质效率显著高于对照组.试验组与对照组罗非鱼成活率的差异不大,均在97%以上.     

酸制剂对罗非鱼生长和饲料利用的影响

为考察不同酸制剂对奥尼罗非鱼幼鱼生长和饲料利用的影响,在基础饲料(对照组)中分别添加0.3%磷酸、富马酸、柠檬酸和乳酸,饲养奥尼罗非鱼幼鱼9周(初始平均体重约1.9g)。结果表明,添加0.3%柠檬酸和乳酸饲料组的罗非鱼特定生长率显著高于对照组和添加富马酸组(P<0.05);磷酸组、柠檬酸组和乳酸组的饲料效率较对照组有提高趋势(P>0.05),乳酸组的饲料效率显著高于富马酸组(P<0.05);柠檬酸组和乳酸组鱼体水分含量显著高于富马酸组(P<0.05),体粗蛋白、粗脂肪和灰分含量在组间差异不显著(P>0.05);胃蛋白酶活性在富马酸组显著低于其它饲料组(P<0.05),肠淀粉酶活性在柠檬酸组和乳酸组显著高于对照组(P<0.05);肝脏代谢酶活性在柠檬酸组和乳酸组显著高于对照组、磷酸组和富马酸组(P<0.05),相应地,柠檬酸组和乳酸组罗非鱼血清甘油三酯含量显著高于对照组(P<0.05)。结果说明,添加0.3%柠檬酸和乳酸能显著促进罗非鱼幼鱼生长,提高饲料的利用,富马酸降低罗非鱼对饲料的利用。     

罗非鱼饲料中海带渣含量对氨基酸表观消化率的影响↑（*）

罗非鱼饲料中海带渣含量对氨基酸表观消化率的影响ＥＦＦＥＣＴＯＦＬＡＭＩＮＡＲＩＡＲＥＳＩＤＵＥＳＯＮＡＰＰＡＲＥＮＴＤＩＧＥＳＴＩＢＩＬＩＴＹＯＦＡＭＩＮＯＡＣＩＤＳＩＮＤＩＥＴＯＦＯＲＥＯＣＨＲＯＭＩＳＮＩＬＯＴＩＣＵＳ甘纯玑彭时尧施木田（福建农业...     

不同脂肪水平的饲料对圆斑星鲽生长及表观消化率的影响

以鱼粉和酪蛋白为蛋白源,鱼油和豆油为脂肪源,配制成蛋白水平为50%,脂肪水平分别为8%、12%、16%的三组饲料(分别表示为A、B、C组),每组设3个重复,每个重复15尾鱼,进行10周的圆斑星鲽(Verasper variegatus)饲养试验。结果表明:鱼体的生长和表观消化率受饲料中脂肪水平影响显著,各组成活率均较高,A组的增重率显著高于其他两组,饲料系数则随饲料中脂肪水平的升高而有升高的趋势。干物质表观消化率以C组最高且显著高于A组和B组,随饲料中脂肪水平的升高,脂肪表观消化率显著增加。从生产角度考虑,在本实验条件下,圆斑星鲽的最适脂肪需求为8%。     

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.     

Partial replacement of soybean meal by sesame meal in diets of juvenile Nile tilapia,Oreochromis niloticus L.

An 8‐week feeding trial was conducted to determine the effects of replacing of soybean meal (SBM) with sesame meal (SM) in the diets of Oreochromis niloticus fingerlings. Seven practical diets (33 g kg^?1 crude protein, 19.2 MJ kg^?1 dry diet) containing substitution levels of 0%, 8%, 16%, 24%, 32%, 40% and 48% SM for SBM protein were formulated and fed to triplicate groups of O. niloticus fingerlings (mean initial weight of 8.74 ± 0.12 g). The fish survival rate, hepatosomatic index, viscerosomatic index and condition factor were not significantly affected by the contents of SM in the diets (P>0.05). The final body weight, weight gain (WG), specific growth ratio, feed conversion ratio and protein efficiency ratio of the fish fed the diet containing 16% SM were similar (P>0.05) to that of the fish fed the control diet. Except lipid, digestible contents of dry matter, crude protein, ash, gross energy and individual amino acids decreased while phosphorous increased with increasing SM levels. No significant differences were observed in whole‐body dry matter, ash and lipid contents among all the treatments (P>0.05); crude protein contents between fish fed the control diet and a diet containing 24% SM were also not affected significantly (P>0.05), and the phosphorus content was not significantly different when the SM level was increased to 32% (P>0.05). No significant negative differences were observed in the liver composition between fish fed the control diet and the diet containing 24% SM. The most efficient diet in terms of cost per unit WG of fish was obtained in 8% SM dietary substitution, while no significant differences were found among the 0%, 8% and 16% levels. It was indicated that SM can be utilized in the juvenile Nile tilapia diet to replace about 16% of SBM protein without causing negative effects on growth performance, body composition, liver composition and feed utilization.     

Effect of dietary probiotic Biogen® supplementation as a growth promoter on growth performance and feed utilization of Nile tilapia Oreochromis niloticus (L.)

Probiotic microbial feed supplements are gaining wide acceptance in livestock production, and may be applicable to aquaculture production systems. The present study was conducted to examine probiotic treatment in the fingerling diet of Nile tilapia Oreochromis niloticus (L.). A total of 240 of Nile tilapia fingerlings (weight ranged from 22.96 to 26.40 g) were divided into five experimental groups. The experiment was conducted for 120 days. Experimental diets were identical in all, except for the variation in probiotic levels. A probiotic (Biogen^®) was used at 0% (diet 1), 0.5% (diet 2), 1.5% (diet 3), 2.0% (diet 4) and 2.5% (diet 5) inclusion rates in the experimental diets. The growth performance and nutrient utilization of Nile tilapia including weight gain, specific growth rate, protein efficiency ratio, protein productive value and energy retention were significantly (P≤0.01) higher in the treatment receiving probiotic (Biogen^®) than the control diet. No differences were observed for moisture, ash and protein content (P≤0.01) among the experimental diets. The lowest gross energy and lipid contents were recorded for fish fed the diet containing 0.5% Biogen^® (P≤0.01). The production performance and subsequent cost–benefit analyses clearly indicated that the diets containing probiotic biogen recorded the highest net return and the lowest total cost compared with the control diet.     

The effect of dietary protein level on the apparent digestibility coefficient of two selected feed ingredients for Nile tilapia,Oreochromis niloticus L.

The effect of dietary protein level on the apparent digestibility coefficient (ADC) of meat and bone meal and rapeseed meal for Nile tilapia Oreochromis niloticus L. was examined. Three reference diets were formulated to contain 240 (RD24), 350 (RD35) and 450 (RD45) g kg^?1 crude protein, and chromic oxide was added at 10 g kg^?1 in the reference diets as an inert indicator. Six test diets were formulated by mixing one of the reference diets with each test ingredient at a ratio of 70:30. Fish (initial body weight 101.0 ± 0.6 g) were fed reference diets for 3 days and then fed test diets in the following 4 days cyclically for 4 weeks. Faeces of fish fed each reference diet or test diet was collected from the third day of each diet conversion. Dietary protein level significantly affected the ADC of protein and energy of reference diets, test diets and test ingredients. The ADC of protein and energy of meat and bone meal and rapeseed meal was the highest when these ingredients were mixed with diet RD35. The scope of variation in the ADC of protein and energy of meat and bone meal was 8% (from 69.9% to 78.3%) and 8% (from 70.2% to 78.0%), and the scope of variation in the ADC of protein and energy of rapeseed meal was 4% (from 79.8% to 83.3%) and 5% (from 56.0% to 60.7%) when the dietary protein level was increased from 300 to 480 g kg^?1. This indicates that the ADC of protein and energy of meat and bone meal and rapeseed meal for Nile tilapia varied considerably at different dietary protein levels.     

Brown propolis extract in feed as a growth promoter of Nile tilapia (Oreochromis niloticus, Linnaeus 1758) fingerlings

This study assessed the use of increasing levels of brown propolis extract (BPE) as a growth promoter in Nile tilapia fingerling feeds. In a complete randomized design, 75 Nile tilapia fingerlings with 60 days on average and weighing 4.1±0.1 g were assigned to 25 aquaria (60 L) and subjected to 5 treatments in 5 repetitions for 30 days. Propolis from Serra do Araripe, Cariri Region, South Ceará State – Brazil was used to produce the BPE. The treatments involved the addition of BPE to feed samples (0.91, 1.83, 2.74 and 3.65 g kg⁻¹) and feed control (without BPE). The final mean weight and the percentage of weight gain varied quadratically with the increase in BPE ( P <0.01), with a maximum of 2.22 g kg⁻¹. The other evaluated parameters were not affected by the treatments ( P >0.05). The level of best performance parameters was 2.22 g kg⁻¹, between the levels of 1.83 and 2.74 g BPE kg⁻¹ feed inclusion. These results indicate the potential to use the brown propolis extract as a growth promoter to Nile tilapia fingerlings.     

Effect of dietary betaine levels on growth performance and hepatic intermediary metabolism of GIFT strain of Nile tilapia Oreochromis niloticus reared in freshwater

An 8‐week feeding experiment was conducted to determine the effect of dietary betaine levels on the growth performance and hepatic intermediary metabolism of genetically improved farmed tilapia (GIFT) strain of Nile tilapia Oreochromis niloticus (mean initial body weight: 78.3 ± 1.3 g, means ± SD). Six practical diets were formulated with the incorporation of betaine at the levels of 0 (control), 5, 10, 15, 20 and 25 g kg⁻¹. Survival showed no significant differences among the treatments (P > 0.05). The highest and lowest weight gain (WG) and specific growth rate (SGR) were observed for fish fed the diets containing 5 and 0 g kg⁻¹ (control) betaine, respectively. Feed intake showed similar trend with WG and SGR. In contrast, feed conversion ratio was the lowest when dietary betaine level was 5 g kg⁻¹. In general, dietary betaine supplementation showed no significant effect on hepatic composition of tilapia. Condition factor and viscerosomatic index tended to increase with increasing dietary betaine levels from 0 to 5 g kg⁻¹ and then decline when dietary betaine levels further increased from 5 to 25 g kg⁻¹. In contrast, hepatosomatic index declined with increasing dietary betaine levels (P < 0.05). Dietary betaine levels significantly influenced several hepatic enzymatic activities, including succinate dehydrogenase, lactate dehydrogenase, malic dehydrogenase, lipoprotein lipase and hepatic lipase, suggesting that dietary betaine addition had significant effects on nutrient metabolism in the liver. Based on the second‐order polynomial regression analysis of WG, 12.5 g kg⁻¹ of dietary betaine level seemed optimal for genetically improved farmed tilapia strain of O. niloticus.     

Evaluation of hydrolysed rubber seed meal as a dietary protein source for Nile tilapia Oreochromis niloticus L.

This study evaluated the use of hydrolysed rubber seed meal as a locally grown alternative feed ingredient to reduce the use of fishmeal within formulated feeds for tilapia. Five experimental diets were prepared by formulating different inclusion levels of hydrolysed rubber seed meal (0%, 25%, 50%, 75% and 100% of plant‐based protein contribution). Dried and defatted rubber seed meal was hydrolysed by adding rumen digesta liquid to the ingredient. For digestibility measurement, chromic oxide was added to each diet as an inert marker. The digestibility trial was conducted over a 14‐day period by collecting faecal matter from the rearing tanks. In addition, a growth trial was conducted over a period of 50 days using four replicates per dietary treatment. In both experiments, all fish were fed three times daily to apparent satiation. At the end of growth trial, the inclusion level of hydrolysed rubber seed meal up to 50% of plant‐based protein contribution did not give any significant difference compared to the control diet in terms of feed efficiency, specific growth rate and protein retention parameters. In the digestibility study, fish fed diets containing hydrolysed rubber seed meal up to a 50% of plant‐based protein inclusion level did not give any significant difference compared to the control diet in terms of protein and dry matter apparent digestibility. Based on the result of this growth and digestibility study, up to a 50% of plant‐based protein contribution of hydrolysed rubber seed meal can be used within formulated tilapia feeds without any adverse effect.     

Combined effect of temperature,salinity and density on the growth and feed utilization of Nile tilapia juveniles (Oreochromis niloticus)

Based on Box–Behnken experimental design and response surface method, the joint effect of temperature (16–36°C), salinity (0–22 ppt) and rearing density (200–1000 fish.m^?3) on the specific growth rate (SGR) and feed conversion rate (FCR) of Nile tilapia juveniles were studied under laboratory conditions. The entire experiment lasted for 1 month (30 days). Results showed that the linear and quadratic effects of temperature, salinity on both growth and feed utilization were highly statistically significant (P < 0.01). The linear and quadratic effect of rearing density on the growth was highly significant (P < 0.01); the linear effect of rearing density on feed utilization was significant (P < 0.05), but the quadratic effect nonsignificant (P > 0.05). Interactions between temperature and salinity, and between salinity and rearing density on the growth statistically differed from zero (P < 0.05). Interactions between temperature and salinity, between temperature and density on feed utilization was significant (P < 0.05). Model equations of the growth and feed utilization on temperature, salinity and density were established, with the coefficient of determination being 98.34% for growth and 98.11% for feed utilization, and could be applied to projection. The optimal temperature/salinity/density combination was obtained utilizing statistical optimization approach: 29°C/6 ppt/500 fish.m^?3, at which the maximal specific growth and feed utilization reached 4.228%.d^?1 and 0.520 respectively, with the desirability being 0.989.     

Effects of pretreatment with microbial phytase on phosphorous utilization and growth performance of Nile tilapia (Oreochromis niloticus)

This study was to assess effects of the pretreatment in all‐plant based diets with microbial phytase on phosphorous utilization and growth performance of Nile tilapia (Oreochromis niloticus). Pretreatment trials were conducted using phytase at graded doses to determine the optimal dose of phytase. Available phosphorus (P) levels increased significantly with the increased doses of phytase and the dose of 1000 U kg^?1 was most efficient. Based on the pretreatment trials, plant based diets for Nile tilapia were formulated by pretreating with phytase at 1000 U kg^?1. Experimental diets were supplemented with graded levels of mono calcium phosphate (MCP) at 25, 18.75, 12.5, 6.25 and 0 g kg ^?1 diet. In addition, there were three controls: one phytase control, one inorganic P control and one pretreatment control. The results showed that diets pretreated with phytase gave better growth performance, feed conversion ratio and protein efficiency ratio of Nile tilapia compared with the phytase control diet and pretreatment control diet (P < 0.05). There were no significant differences in growth performance of Nile tilapia between the inorganic control diet and phytase pretreated diets supplemented with MCP at 25, 18.75 and 12.5 g kg^?1 (P > 0.05), which resulted in significantly better performance than those at 6.25 and 0 g kg^?1 (P < 0.05). Dietary interaction effects of phytase were observed for phosphorus retention efficiency and phosphorus load. Apparent digestibility coefficient of P (ADCp) was improved significantly by phytase pretreatment (P < 0.05). No significant difference was detected on ADC of crude protein among all experimental diets (P > 0.05).     

Nutritional evaluation of waste date fruit as partial substitute for soybean meal in practical diets of juvenile Nile tilapia, Oreochromis niloticus L.

The potential of waste date meal (WDM; low-quality date palm, Phoenix dactylifera L.) as a carbohydrate source in formulated diets for Nile tilapia was evaluated. Four isocaloric-practical diets (15.7 kJ g⁻¹) were formulated incorporating WDM at 0, 100, 200 and 300 g kg⁻¹ levels as partial substitutes for soybean meal (SBM). These were designated D₀ [284 g crude protein (CP) and 383 g carbohydrate (CHO) kg⁻¹ diet], D₁ (279 g CP and 446 g CHO kg⁻¹ diet), D₂ (207 g CP and 495 g CHO kg⁻¹ diet) and D₃ (175 g CP and 578 g CHO kg⁻¹ diet). Each diet was fed to three replicate groups of 30 fish [20.20 ± 0.09 g (±SE)] for 75 days. No feed-related mortality was observed during the entire experimental period. Final body weight (FBW) and specific growth rate (SGR) in the different treatments were statistically not significantly different ( P  > 0.05). Protein efficiency rate (PER) was lowest in diet D₀ and increased with decrease of SBM content (D₁–D₃). A significant increase in whole body lipid content was recorded in fish fed diets D₂ and D₃. Results showed that WDM could be a substitute for SBM up to 300 g kg⁻¹ in practical Nile tilapia diets without compromising growth.