Effects of prebiotics on nutrient digestibility of a soybean‐meal‐based diet by red drum Sciaenops ocellatus (Linnaeus)

The present study examined the effects of four prebiotic compounds on nutrient and energy digestibility of soybean‐meal‐based diets by red drum (Sciaenops ocellatus). The experimental diets contained 40% crude protein of which approximately half was provided by soybean meal with the remainder from menhaden fish meal. The four prebiotics GroBiotic^®‐A (a mixture of partially autolysed brewers yeast, dairy ingredient components and dried fermentation products), mannanoligosaccharide (MOS), galacto‐oligosaccharide (GOS) and inulin were individually added to the basal diet at 1% by weight. A diet with all its protein provided by menhaden fish meal was also included as a control. This control diet had the highest apparent digestibility coefficient (ADC) values – 87% for protein, 87% for lipid, 78% for organic matter and 83% for energy. The basal soybean‐meal‐based diet supplemented with GroBiotic^®‐A, GOS and MOS had significantly (P<0.05) increased protein (82%, 82%, 82% respectively) and organic matter ADC values (69%, 64%, 66% respectively), compared with the basal diet (69% for protein and 49% for organic matter). However, the lipid ADC values were significantly decreased for fish fed with the diets supplemented with inulin, GOS and MOS (63%, 61%, 61% respectively) compared with the basal diet (77%) but not for those fed GroBiotic^®‐A (82%). Energy ADC values were also increased in fish fed with the GroBiotic‐A^®, GOS and MOS diets (73%, 70%, 72%), compared with the basal diet (57%); however, fish fed with the inulin diet had an energy ADC value (54%) similar to that of fish fed with the basal diet. Thus, the present study is the first to demonstrate that nutrient and energy digestibility of soybean‐meal‐based diets by red drum can be enhanced with prebiotic supplementation.     

First data on growth of cultured brown meagre Sciaena umbra using diets with different protein and fat contents

ABSTRACT:   Brown meagre Sciaena umbra Linnaeus 1758 is a demersal species living at depths of 0–200 m with a wide distribution in the Mediterranean Sea, Black Sea and eastern Atlantic Ocean. It exhibits nocturnal behavior and occupies bottom caves and seabeds covered with vegetation. This study presents the first data on brown meagre growth under culture conditions and contributes some basic information on its dietary protein requirement by feeding isoenergetic diets with different protein–lipid ratios by means of self-feeders. Fish with 78.8 ± 15.8 g (mean ± standard deviation) body weight were divided into four groups and subjected to four different feeding regimes with three replications for 77 days. In the first group, fish were supplied with a high protein and low fat diet (HPLF, 52 : 8 w/w fat–protein ratio), the second one a medium protein and medium fat diet (MPMF, 42 : 14), the third with a low protein and high fat diet (LPHF, 31 : 23). In the fourth group, fish had access to both HPLF and LPHF diets. Fish fed on HPLF and MPMF diets showed significantly better growth and feed conversion ratios than fish fed on the LPHF diet. Fish with access to HPLF and LPHF diets exhibited comparable growth to the HPLF group but their feed conversion ratio was significantly higher. The condition factor and hepatosomatic index revealed no significant differences between dietary regimes. The liver of brown meagre may serve as a depository organ for energy, judging from its relatively high lipid content (39–43%).     

不同氮素形态对干旱胁迫杉木幼苗养分吸收及分配的影响

【目的】干旱胁迫是限制植物生长的重要非生物因素之一,而适宜的氮素营养可以提高植物的抗旱性。本文探讨了供应不同形态氮源对干旱条件下杉木[Cunninghamia lanceolata (Lamb.) Hook]幼苗养分吸收及分配的影响。【方法】采用水培试验,供试杉木材料为2个无性系幼苗(7–14号和8–8号),在营养液中添加10%(w/v)PEG-6000进行干旱胁迫。营养液中的氮源处理包括硝态氮、铵态氮、硝铵混合氮,氮素浓度均为4.571mmol/L,每个品种均设6个处理。培养20天后,测定了杉木幼苗根、茎、叶的养分含量及生物量。【结果】与正常水分供应相比较,干旱胁迫条件下供应铵态氮可促进叶片N、K以及茎叶P、K的吸收,供应混合氮可促进根部K的吸收;供应铵态氮可促进根、茎对Ca的吸收,对叶片Ca无明显作用。干旱胁迫对根部Fe、Mn、Cu、Zn吸收量影响显著,氮素供应不同程度地降低了干旱胁迫下各器官Mg、Fe、Mn和Cu吸收量,表现为抑制吸收,但添加铵态氮比硝态氮的降低幅度小。3个氮源处理均降低了干旱条件下根部Zn吸收量,但没有降低甚至增加了茎、叶中Zn的吸收量,说明氮营养可调节Zn在各器官间的分配,缓解干旱导致的缺锌现象。不同器官之间各养分吸收量差异显著,3个氮源处理中,N和P吸收量表现为叶>根>茎,K和Ca为叶>茎>根,Fe、Cu为根>叶>茎,Mg、Mn和Zn在各器官之间的分配规律不一。铵态氮吸收量均表现为叶>根>茎,且各器官铵态氮吸收量显著高于硝态氮,说明杉木具有明显的喜铵特性。【结论】在干旱胁迫下,氮素供应形态显著影响杉木幼苗对养分的吸收及在各器官中的分配,作用效果因家系品种和元素种类而异。总体来讲,铵态氮提高干旱胁迫下杉木幼苗养分吸收的效果好于硝态氮,杉木可以认为是喜铵植物。     

Broiler Litter as a Sole Nutrient Source for Cotton: Nitrogen,Phosphorus, Potassium,Calcium, and Magnesium Concentrations in Plant Parts

Abstract

The ability of poultry litter to support plant growth by supplying essential plant nutrients in the absence of other sources of the nutrients has not been studied thoroughly. The objectives of this research were to (1) determine the ability of poultry litter, as the sole nutrient source, to provide macronutrients and support growth of cotton (Gossypium hirsutum L.) (2) evaluate the distribution of these nutrients within the different plant parts, and (3) estimate the efficiency with which these nutrients are extracted by cotton. The research was conducted in plastic containers filled with a 2:1 (v/v) sand:vermiculite growing mix under greenhouse conditions. The treatments included broiler litter rates of 0, 30, 60, 90, or 120 g pot^?1 with or without supplemental Hoagland's nutrient solution. Broiler litter supplied adequate amounts of the macronutrients nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) and supported normal growth of cotton. Tissue nutrient analysis showed that the concentration of N, P, K, and Mg in the upper mainstem leaves was within published sufficiency ranges for cotton growth. Evaluation of the N distribution indicated that the cotton plant partitions N to reproductive parts when faced with deficiency of this nutrient and favors allocating N to new leaf growth once the requirement for reproductive growth is met. The partitioning of P was similar to that of N but less distinct. Cotton extracted Mg and K with greater efficiency (up to 58%) than the other nutrients and stored these nutrients in older leaves. The extraction efficiency of N ranged between 21% at 120 g pot^?1 litter and 27% at 30 g pot^?1 litter. Phosphorus was the most poorly extracted nutrient, with only 16% of the total applied P extracted when 30 g pot^?1 litter was applied and only 6% extracted at the higher litter rates. This suggests that the same problem of P buildup that has been reported in soils under pasture may also occur when poultry litter is repeatedly applied to the same soil planted to cotton. These results show that broiler litter not only supplied enough N but also supplied the four other macronutrients (P, K, Ca, and Mg) in amounts sufficient to support normal cotton growth. This research implies that poultry litter can effectively substitute for several fertilizers to meet crop macronutrient (N, P, K, Ca, and Mg) needs in soils deficient in any or all of these nutrients.     

Increased plant nitrogen loss with increasing nitrogen applied in winter wheat observed with 15nitrogen

Nitrogen (N) fertilizer is generally the most costly input for winter wheat (Triticum aestivum L.) production. Therefore, it was important to maximize fertilizer use efficiency and minimize N losses to the environment. One of the mechanisms responsible for decreased N use efficiency (NUE) was plant N loss. The objectives of this experiment were to determine fertilizer N recovery in winter wheat when produced for forage and grain, and to quantify potential plant N losses from flowering to maturity in winter wheat. Two long‐term (>25 years) winter wheat (Triticum aestivum L.) N rate fertility experiments (Experiment 222 and Experiment 502) were selected to evaluate ¹⁵N fertilizer recovery. Percent ¹⁵N recovery was determined from all microplots in plant tissue at flowering, in the grain, and straw at harvest and in the soil. Fertilizer N(¹⁵NH₄ ¹⁵NO₃) was applied atratesof 0, 45, 90, and 135kg N ha^‐1 in Experiment 222, and 0, 22, 45, 67, 90, and 112 kg N ha^‐1 in Experiment 502. The ratio ofNO₃ ^‐to NH₄ ⁺ in wheat forage at flowering was positively correlated with estimated plant N loss. Estimated plant N loss (total N uptake in wheat at flowering minus N uptake in the grain and straw at maturity) ranged from a net gain of 12 kg N ha^‐1 to a loss of 42 kg N ha^‐1, and losses increased with increasing N applied.     

Combined effect of weaning time and co‐feeding duration on growth and survival of peled Coregonus peled (Gmelin) larvae

The study investigated the combined effect of weaning from live feed to a commercial dry pellet at 10, 15, 20, 25 or 30 days posthatching (dph) and co‐feeding for 1, 3 or 6 days on survival and growth of Coregonus peled larvae. Additional groups fed only live Artemia sp. nauplii (ART), and only Biomar LARVIVA ProWean 100 (DRY) were included. A final survival rate of 66.4%–85.5% was observed in groups weaned after 20 dph. Final body weight (BW) and total length (TL) were significantly lower in groups weaned at 10 and 15 dph, regardless of the duration of co‐feeding. Larvae reached 29–37 mg BW and TL of 17.7–19.0 mm in groups weaned at 20, 25 and 30 dph. The recommended minimum duration of feeding with live food, based on these results, is 20 days. Based on the significantly higher yield of larvae weaned after 20 dph irrespective of co‐feeding duration, it can be concluded that abrupt weaning to dry food after 20 days of feeding with live prey can provide adequate production while reducing the effort and costs associated with live feed.     

婴幼儿配方乳粉的设计及其体外消化

根据母乳中各宏量营养素的特点,通过调节配方乳粉中蛋白质、脂肪和碳水化合物的含量,设计了适合我国婴幼儿食用的配方乳粉,并对该配方乳粉进行了体外消化实验,以考察该配方乳粉配方设计的合理性.结果表明:配方乳粉中各宏量营养素含量均符合国内外标准要求,能满足婴幼儿对宏量营养素的需求.该配方乳粉总消化率在88％左右,优于市售配方乳粉和羊乳粉,且在酶含量提高的情况下,该配方乳粉蛋白质消化率可达95％,表明该配方乳粉配比合理,利于婴幼儿消化吸收.     

几种海水和淡水贝类的大宗营养成分比较研究

分别对3种淡水贝和3种海水贝的大宗营养成分进行了较为系统的研究。总体而言,这6种贝的水分含量相差不大,但粗蛋白、粗脂肪和灰分含量却相差明显。其中,波纹巴非蛤和长竹蛏属于高蛋白贝类,其蛋白占干物质的75%,而其脂肪和灰分含量中等,分别占8%和14%左右;近江牡蛎和河蚌属于多脂肪贝类,其脂肪含量在所测贝类中最高,约占干物质的14%,而蛋白和灰分则相对较少,分别为14%和6%;螺蛳和中华圆田螺属于高灰分贝类,其灰分含量高达27%,蛋白居中(60%),而脂肪最低(3%)。在蛋白质量方面,这几种贝类的氨基酸评分总体略低于全鸡蛋蛋白,但其赖氨酸评分优于全鸡蛋蛋白,在与粮谷类的搭配上具有更明显的蛋白质增效作用。在脂肪质量方面,海水贝的多不饱和脂肪酸特别是EPA和DHA明显比淡水贝高,如属于海水贝的长竹蛏、波纹巴非蛤、近江牡蛎的EPA和DHA的含量总和分别为14.19%、25.51%和34.29%,而属于淡水贝的中华圆田螺完全不含EPA或DHA,海水贝在脂肪营养方面明显优于淡水贝。在矿物质营养方面,淡水螺表现出非常明显的优势,有开发成补充多种矿物质之天然膳食补充剂的潜力。本研究对指导人们按各自的营养需求选择不同的贝类品种具有非常重要的意义。研究亮点:比较分析了3种海水贝和3种淡水贝之间的大宗营养成分,并按各种贝类的营养特点,将贝类初步分为3类,即以波纹巴非蛤和长竹蛏为代表的高蛋白贝类、以近江牡蛎和河蚌为代表的多脂肪贝类、以中华圆田螺和螺蛳为代表的高灰分贝类,这对引导人们按需选择贝类具有非常重要的意义,同时对于贝类的加工利用和开发各具特色高附加值贝类产品具有很好的指导作用。     

不同林龄杉木针叶大量元素转移特征

为探究不同林龄杉木成熟叶与衰老叶之间大量元素的转移规律,选择中国亚热带地区8、14、21、46年生杉木,测定其成熟叶和衰老叶中N、P、K、Ca、Mg含量。结果表明:不同林龄杉木成熟叶中养分含量差异显著(Mg除外),但未表现出有规律的变化,衰老叶中N、K、Mg含量不受林龄的影响。不同林龄杉木针叶大量元素平均转移率表现为REK>REP>REN>REMg>RECa,其中,Ca表现为负转移,不同林龄杉木针叶N、K、Mg转移率无显著差异。在杉木成熟叶中,P、K、Ca、Mg含量与其转移率存在极显著的线性正相关,杉木衰老叶片中营养元素均与其转移率存在负相关。研究表明:杉木通过将大量元素从衰老叶片转移到成熟叶片,从而减少养分损失,这种机制不随林龄增加而衰退。     

Growth,Nitrate Accumulation,and Macronutrient Concentration of Pakchoi as Affected By External Nitrate-N: Amino Acid-N Ratio

ABSTRACT

A study was carried out to determine the influence of nitrogen (N) sources on the growth, nitrate (NO₃ ^?) accumulation, and macronutrient concentrations of pakchoi (Brassica chinensis L.) in hydroponics. Plants were supplied with NO₃ ^? and two amino acids (AA), glutamic acid (Glu), and glutamine (Gln), at six NO₃ ^?-N/AA-N molar ratios: (1) 100:0, (2) 80:20, (3) 60:40, (4) 40:60, (5) 20:80, (6) 0:100. The total N concentration was 12.5 mmol/L for all treatments in nutrient solutions. Both AAs reduced plant growth with decreasing NO₃ ^?-N/AA-N ratios, but the reduction was for Gln than for Glu. At 80:20 NO₃ ^?-N: Gln-N ratio, the Gln had no significant effect on pakchoi fresh weights. Decreasing NO₃ ^?-N/AA-N ratios reduced NO₃ ^? concentrations in the plant, regardless of AA sources. Adding an appropriate portion of AA-N to nutrient solutions for hydroponic culture increased concentrations of N, phosphorus (P), and potassium (K) in pakchoi shoots. Substituting 20% or less of NO₃ ^?-N with Gln-N in hydroponic culture will increase the pakchoi quality by reducing NO₃ ^? concentration and increasing mineral nutrient concentrations in shoots without significant reduction of crop yields.