Effective use of glucose rather than starch in formulated semimoist diets of common octopus (Octopus vulgaris)

The aim of the present work was to test the capacity of O. vulgaris to use carbohydrates supplied in three diets: a diet without added carbohydrates (diet C0: 500 g kg^?1 water, 200 g kg^?1 gelatine, 100 g kg^?1 egg yolk powder, 50 g kg^?1 freeze‐dried Sardinella aurita and 150 g kg^?1 freeze‐dried Todarodes sagittatus), and two obtained by substituting 50 g kg^?1 of T. sagittatus by glucose (diet GLU50) or by starch (diet STA50). The most stable and best accepted diet was STA50 (SFR 1.26%BW day^?1), although there were no significant differences in the growth rates obtained with the three diets: 10.1 g day^?1, 9.4 g day^?1 and 11.2 g day^?1 for C0, GLU50 and STA50, respectively (P > 0.05). The feed efficiency indices were better for GLU50, of particular note being the protein productive value of 72% and a feed conversion ratio lower than 1. Protein and lipid digestibility were similar in all three diets (96–98% for proteins and 85–94% for lipids), whereas carbohydrate digestibility was higher in GLU50 (98%) than in C0 (84%) and STA50 (0.33%). The content of carbohydrates increased in muscle and the digestive gland as a consequence of the increased carbohydrates intake.     

秋季刈割对紫花苜蓿主根贮藏有机物质的影响

为了解秋季刈割对紫花苜蓿根贮有机物质在越冬期间变化情况及对翌年越冬率、头茬产量的影响,本文以‘公农1号’紫花苜蓿为试验材料,测定第二次刈割后900GDD,1000GDD,1100GDD,1200GDD刈割的紫花苜蓿在2013年秋末至2014年初春越冬期间主根中非结构性碳水化合物和含氮化合物的含量。结果表明:种植翌年,第二次刈割后1000GDD刈割的紫花苜蓿越冬率及头茬产量显著高于其他刈割处理(P < 0.05),与未刈割处理间差异不显著;整个越冬期间,紫花苜蓿根贮藏性有机物质含量呈先上升后下降的趋势。综上所述,吉林省中东部地区秋季刈割具有可行性,且在第二次刈割后1000GDD时刈割不会影响牧草翌年产量。     

Fibre analysis and fibre digestibility in pet foods--a comparison of total dietary fibre, neutral and acid detergent fibre and crude fibre

Six dry dog foods and six dry cat foods with different carbohydrate sources were investigated in digestion trials. Food and faecal samples were analysed for CF, TDF and starch. In dogs, also neutral detergent fibre (aNDFom) and acid detergent fibre (ADFom) were analysed. N-free extract (NfE) was calculated for CF, and similarly for all other fibre analyses. Linear regressions were calculated between fibre intake and faecal fibre excretion. True digestibility was calculated from the regression coefficients [true digestibility in % = (1 - regression coefficient)*100], with the intercept of the equation representing excretion of material of non-food origin. Crude fibre analyses gave the lowest values, and TDF the highest, while ADFom and aNDFom were in between. Variation between diets was lowest in CF and highest in TDF. Total dietary fibre, aNDFom and ADFom in food were positively correlated. Crude fibre in food did not correlate with any other method. The NfE analogue for TDF was closest to the starch content. Methods of fibre analyses in faeces did not agree very well with each other. Crude fibre had the lowest apparent digestibility, followed by ADFom, TDF and aNDFom. For all fibre analyses, there was a significant correlation between fibre intake and faecal fibre excretion. True digestibility was close to zero for CF, with a high uniformity in both species. In dogs, true digestibility of aNDFom was 53%, of ADFom 26% and of TDF 37%; in cats, true digestibility of TDF was 31%. Except for CF, the intercept of the regression equations suggest that faecal excretion of some material of non-food origin is analysed as fibre. A combination of TDF and CF analyses might give good information on the content of total (TDF), unfermentable (CF) and partially fermentable fibre (TDF-CF) in pet foods.     

Fermentation of six different forages in the semi-continuous fermentation technique Caesitec

The aim of the present study was to compare carbohydrate degradation of forages which store carbohydrates either predominantly as fructan or starch, in horses’ hindgut. The effects of an abrupt change from hay‐based feeding to green fodder‐based feeding on the caecal flora were tested with the in vitro hindgut simulation technique ‘Caesitec’. Six trials with different forages (English ryegrass, tall fescue, grass mixture‐horses, grass mixture‐cows, lucerne, white clover) were conducted. During a 4‐day stabilisation period, samples were taken once a day before loading the fermenters with hay. After diet‐change to forage‐based feeding, samples were taken four times a day. Ammonia and pH‐value were measured before and 1, 2 and 6 h after loading the ‘Caesitec’. Gas formation was measured daily. Bacterial numbers, lactate and short chain fatty acids were detected at four time‐points of each trial. The grass mixtures contained the highest amounts of fructan. The pH‐values were in the physiological range from pH 6 up to 7 (6.58–6.83) by feeding all forages. Gas formation, anaerobic and aerobic bacterial numbers increased after diet change from hay to any forage. The maximum amount of fructan (3.75 g/kg) in swiss pasture did not cause a permanent pathological change in the hindgut‐flora.     

青海云杉休眠前后非结构性碳水化合物含量随海拔变化

[目的]冬季低温是决定高山林线树种能否生存的重要生态因素。休眠前后树木体内碳水化合物的变化能够反映出其安全越冬的策略。但目前高山林线树种休眠前后体内碳水化合物的变化及机理尚不清楚。为了探讨林线树种越冬期间的生存策略,[方法]本文以祁连山林线青海云杉为对象,研究了不同海拔(2 900、3 000、3 100、3 200、3 300 m)成年树枝、叶休眠前后非结构性碳水化合物含量变化,包括可溶性糖(葡萄糖和果糖)、淀粉以及糖/淀粉比值的变化。[结果]表明:(1)休眠前青海云杉当年及1年生叶在高海拔处NSC含量高于中、低海拔处NSC含量,而在枝条中高、中、低海拔间没有显著差异。(2)休眠后叶中NSC含量最高值在中海拔3 100 m处,显著高于高海拔;不同组织中NSC含量高于休眠前,叶片中尤为明显。(3)与休眠前相比,休眠后可溶性糖及淀粉含量增加,淀粉含量增加幅度显著,引起可溶性糖/淀粉比值降低。[结论]青海云杉休眠前贮存足够的碳水化合物保证越冬期间的细胞渗透调节及能量代谢,并且休眠后气温升高时叶片和枝条的NSC能够得到迅速补充,为新枝条萌发提供充足的碳源,反映了青海云杉在越冬期间的生存策略。     

How potassium deficiency alters flower bud retention on cotton (Gossypium hirsutum L.)

Potassium (K) is fundamental for plant growth and development but despite the increased quantities of fertilizers applied, incidents of K deficiency are commonly observed. The objective of this study was to record the effects of K deficiency during cotton’s (Gossypium hirsutum L.) early reproductive stage on carbohydrate content and metabolism, total antioxidant capacity and oxidative damage of cotton flower buds as well as the physiology of the leaf, subtending to the flower buds. Growth chamber experiments were conducted using cotton cultivar DP0912 and treatments consisted of normal K and deficient K fertilization for the duration of the experiment. Potassium deficiency resulted in significant oxidative damage in the cotton flower buds, despite the substantial increase in their total antioxidant capacity. Sucrose metabolism of the flower buds was markedly affected resulting in significant reductions in all non-structural carbohydrate concentrations. Furthermore, K deficiency disturbed leaf physiology leading to increased membrane damage, decreases in chlorophyll and carotenoid content and ultimately leaf photosynthetic rates. Concomitant increases in specific leaf weight under K deficient conditions indicated reductions in photoassimilate translocation, which in conjunction with the disruptions observed in flower bud sucrose metabolism, due to the insufficient antioxidant response, resulted in significant decreases in flower bud retention.     

末次刈割时间和低温处理对苜蓿根颈抗寒性的影响

【目的】探究科尔沁沙地生境中不同末次刈割时间紫花苜蓿抗寒性及其与低温胁迫下糖类物质含量变化的关系,为科尔沁沙地苜蓿抗寒越冬提供理论依据和技术指导。【方法】以公农1号紫花苜蓿为材料,于2020年8月25日-11月5日进行不同末次刈割时间处理,每处理间隔10 d,以未刈割为对照;于封冻前期（11月15日）挖取不同处理苜蓿越冬器官(根颈)分别进行-10,-15,-20,-25,-30 ℃低温冷冻处理,以4 ℃处理为对照,测定各处理紫花苜蓿根颈的相对电导率及可溶性糖、蔗糖、果糖和淀粉含量,利用相对电导率根据logistic回归方程计算苜蓿的半致死温度,并对半致死温度与糖类物质含量进行相关性分析。【结果】未刈割和8月25日、9月5日、9月15日、9月25日、10月5日、10月15日、10月25日及11月5日末次刈割处理苜蓿的半致死温度分别为-18.03,-17.61,-17.03,-16.59,-15.80,-15.82,-16.83,-16.34和-17.12 ℃,表明在科尔沁沙地生境下不同末次刈割时间苜蓿的抗寒性表现为：未刈割＞8月25日刈割＞11月5日刈割＞9月5日刈割＞10月15日刈割＞9月15日刈割＞10月25日刈割＞10月5日刈割＞9月25日刈割;随着处理温度的降低,苜蓿根颈可溶性糖含量呈先升高后降低的变化趋势,蔗糖含量变化因刈割时间不同表现有别,果糖含量呈增加-降低-增加的双峰型变化趋势,淀粉含量呈逐渐降低的变化趋势;紫花苜蓿根颈的半致死温度与-10,-20,-30 ℃下的可溶性糖含量呈极显著负相关（P＜0.01）,与-15和-20 ℃下的蔗糖含量呈显著或极显著负相关（P＜0.05或P＜0.01）,与-15 ℃下果糖含量呈极显著负相关（P＜0.01）,与-15和-20 ℃下淀粉含量呈极显著正相关。【结论】末次刈割时间可调控苜蓿根颈淀粉向可溶性糖的转化,进而通过蔗糖和果糖等可溶性糖协同作用来维持细胞的渗透压,进而提高苜蓿的抗寒性。     

The dependance of root growth potential on light level,photosynthetic rate,and root starch content in jack pine seedlings

Number of new roots (root growth potential or RGP), new root length, photosynthesis, total nonstructural carbohydrate content of needles and roots, terminal bud condition, and shoot elongation were measured on jack pine container seedlings for 4 weeks at weekly intervals under greenhouse conditions of 100%, 20%, and 10% sunlight to simulate competition-induced, lower light levels in the field. Both lower light levels significantly reduced photosynthetic rate, RGP, new root length, total nonstructural carbohydrate (especially starch) content of needles and roots, speed of terminal bud flush, and shoot growth. Both light level and photosynthetic rate were positively correlated with RGP and new root length, indicating that jack pine seedlings may use current photosynthate as an energy source to support new root growth. RGP and new root length were also both negatively correlated with root starch content suggesting that jack pine seedlings may also use stored carbohydrates as a potential carbon source for root initiation and initial root growth.     

Stock quality and field performance of Pinus patula seedlings produced under two nursery growing regimes during seven different nursery production periods

Two types of containerized P. patula seedlings, referred to as hard and soft seedlings, were raised by droughting and different fertilizer applications. Hard seedlings were raised by applying half the water and a quarter of the fertilizer (0.01 g per seedling 21%N:7.1%P:14.2%K) applied to the soft seedlings. At the end of the nursery cultural treatments the two types of seedlings were morphologically distinct. Hard seedlings had lower heights, height to root collar diameter ratios and seedling dry masses than soft seedlings, but mortality was similar for both seedling types when planted during seven different production periods within the planting season on three sites which differed climatically and geologically. Correlations between mortality and height to root collar diameter ratio (r = 0.76), root to shoot ratio (r = 0.83) and root growth potential (r = --0.69) were obtained indicating that grading of seedlings on these parameters may improve survival. However, it was evident that survival could be significantly improved by identifying the best time of year and conditions for planting, as well as improving stock quality.