耕作方式和秸秆覆盖对旱地麦豆轮作下小麦籽粒产量、蛋白质含量和土壤硝态氮残留的影响

为明确耕作方式和秸秆覆盖对旱地麦豆轮作下小麦籽粒产量、蛋白质含量和土壤硝态氮残留的影响,2014年10月-2016年6月,利用设置在豫西典型旱作区的麦豆轮作栽培模式长期定位试验,选取传统翻耕、翻耕覆盖、旋耕和旋耕覆盖4个处理,比较了小麦氮素吸收利用、籽粒产量、蛋白质含量以及土壤硝态氮残留量。结果表明,与翻耕相比,旋耕不影响小麦产量,但花后氮素积累量、籽粒蛋白质含量和蛋白质产量分别降低60.0%、8.6%和13.0%,而成熟期0~200 cm土层硝态氮残留量显著提高28.6%。同一耕作方式下,秸秆覆盖较无覆盖不仅显著提高了穗数、穗粒数、千粒重和收获指数,还提高了拔节前和开花后的氮素积累量,促进了营养器官氮素向籽粒中转运,从而使翻耕覆盖的籽粒产量、氮素吸收效率、籽粒蛋白质含量和蛋白质产量较翻耕分别提高11.5%、13.5%、7.4%和21.3%,旋耕覆盖较旋耕也分别提高23.0%、39.5%、12.8%和38.5%。在试验进行7年后的小麦成熟期,翻耕覆盖0~200 cm土层硝态氮残留量较翻耕降低31.3%,旋耕覆盖较旋耕也降低51.4%。因此,秸秆覆盖不仅可提高旱地麦豆轮作下小麦产量、蛋白质含量和氮素吸收效率,还能降低土壤硝态氮的残留量,是兼顾旱地小麦高产优质和环境友好生产的有效途径,尤其以旋耕覆盖效果突出。     

外源粪菌干预对受体猪肠道屏障功能的影响研究

为研究外源粪菌干预对受体猪肠道屏障功能的影响,试验选取初生重相近、胎次相同、同日出生的杜×长×大三元杂交哺乳仔猪12窝,随机分为2组,每组6窝(每窝10~12头)。试验组于1~10日龄隔天灌喂1 m L金华猪粪菌悬液进行外源粪菌干预;对照组灌喂等量无菌0.1 mol/L无菌磷酸盐缓冲液(PBS)。试验期间,仔猪自由哺乳采食和饮水,分别于12日龄和27日龄进行屠宰、采样。结果表明:外源粪菌干预可明显减少腹泻,提高受体猪的平均日增重和成活率(P0.05);外源粪菌干预能显著降低27日龄受体猪肠道隐窝深度(P0.05),显著提高肠道绒毛高度/隐窝深度(P0.05);外源粪菌干预能显著增加肠道杯状细胞数和12日龄肠道分泌型免疫球蛋白A阳性(SIgA~+)细胞数(P0.05),同时显著提高肠道黏蛋白Muc2、紧密连接蛋白ZO-1和Occludin表达水平(P0.05),而27日龄试验组的肠道SIgA~+细胞数与对照组无显著差异(P0.05)。综上可知,外源粪菌干预能通过增加肠道杯状细胞和SIgA~+细胞数、提高黏蛋白和紧密连接蛋白表达的方式调节受体猪肠道屏障功能,具有维持猪肠道功能稳态和促进肠道健康的作用。     

氨基酸与母猪营养

母猪饲养是养猪生产中最重要的环节之一。母猪的营养尤其是蛋白质和氨基酸营养不仅直接影响仔猪的生长性能,而且也对母猪的使用年限和繁殖性能会产生很大影响。母猪蛋白质及氨基酸营养受品种、胎次、母猪体况、产仔数、泌乳量、采食量、哺乳期长短等诸多因素影响,增大了母猪氨基酸营养的研究难度。同时母猪个体较大、研究成本高、试验群体偏小、数据采集困难以及试验误差较大等问题也限制了母猪蛋白质及氨基酸营养的系统研究。本文对母猪的氨基酸营养进行综述,旨在为养猪生产实践中母猪日粮的合理配制提供参考。     

Evaluation of vegetable protein in canine diets: Assessment of performance and apparent ileal amino acid digestibility using a broiler model

Recent technological advances in the human food industry with respect to meat processing have decreased the availability of animal proteins to the pet food industry which typically formulates diets with an excess of animal protein. In the long term, this is not sustainable; thus, alternative protein sources need to be investigated. This study examined three canine diets, comparing a typical animal protein‐based diet (control) with two experimental diets where the animal protein was substituted in part with vegetable protein (formulated based either on total protein or amino acid content) using a broiler model. Each diet was fed to six cages each containing two birds from day 15, 18 cages in total (36 birds). Excreta were collected from days 19 to 21. On day 23, birds were euthanized and weighed, and their ileal digesta were collected and pooled for each cage. In addition, one leg per cage was collected for evaluation of muscle mass. Results showed no significant difference in animal performance (feed intake or live weight gain) or muscle to leg proportion across the diets. Birds fed the control diet and the diet balanced for amino acid content exhibited the greatest coefficients of apparent metabolizability for nitrogen (p < .001). Birds fed the diets that contained partial replacement of animal with vegetable protein generally had greater ileal digestibility of amino acids compared to birds fed the control (animal protein) diet. Analysis of excreta showed no dietary difference in terms of dry matter content; however, birds fed the diet balanced for total protein and the diet balanced for amino acid content had significantly greater excreta nitrogen than the control (p = .038). Overall, the study suggests vegetable proteins when formulated based on amino acid content are a viable alternative to animal proteins in canine diets.     

Evaluating the nutritive profile of three insect meals and their effects to replace soya bean in broiler diet

This study was conducted to evaluate the comparative effect of maggot meal, silkworm meal and mealworm as dietary protein source on the production performance and some aspects of meat quality in broilers. In this regard, maggot meal was reared on chicken offal and poultry waste. Silkworm meal was obtained from silk industry, while mealworm was developed through beetles rearing. A total of 120‐day‐old broiler chicks were randomly divided into four groups where soya bean meal (M0) was replaced with maggot meal (M1), silkworm meal (M2) and mealworm (M3) respectively. Each group was further divided into three replicates. The study was carried out for a period of 5 weeks. Diets containing mealworm significantly reduced overall feed consumption and resulted into higher weight gain (p < .05). Lowest feed conversion ratio (FCR) was recorded for birds fed with mealworm diet (p < .05). Tenderness and juiciness of meat were higher (p < .05) in M3 compared to the control and other treatments. Mortality did not vary between the control and the treated groups. Therefore, it is concluded that insect meal is rich in essential nutrients and could be successfully used in broiler ration without compromising acceptability. In the light of this study, mealworm is the best choice in broiler ration, in comparison with maggot and silkworm.     

Effect of feed intake level and dietary protein content on the body temperature of pigs housed under thermo neutral conditions

Feed intake and diet composition appear to affect the body temperature of pigs. Two trials were conducted to analyse the effect of feed intake level and dietary protein content on the intestinal temperature (IT) of pigs housed under thermo neutral conditions. Ten pigs (64.1 ± 1.3 kg initial body weight) fitted with an ileal cannula were used. A thermometer set to register the IT at 5‐min intervals was implanted into the ileum through the cannula. In both trials, the ambient temperature ranged from 19.1 to 21.6°C and the pigs were fed at 07:00 and 19:00 hr (same amount each time). In trial 1, the pigs were fed daily 1.2 or 1.8 kg of a wheat–soybean meal diet. The IT followed a similar pattern along a 24‐hr period regardless the feed intake level. The IT rapidly increased up to 0.61 and 0.74°C after the morning meal and up to 0.53 and 0.47°C after the evening meal in pigs fed 1.2 and 1.8 kg/d respectively. The postprandial IT was higher in pigs fed 1.8 kg after each meal (p < .05). In trial 2, pigs were fed daily 1.8 kg of a low (11%) or a high (22%) crude protein diet. The IT followed a similar pattern along the 24‐hr period regardless the dietary protein level. The postprandial IT did not differ between pigs fed the low protein or the high protein (p > .10). The IT rapidly increased up to 0.66 and 0.62°C after the morning meal in pigs fed the high‐ and low‐protein diet (p < .05), but there was no change after the evening meal (p > .10). In conclusion, the feed intake level affected the IT of pigs housed under TN conditions, but the dietary protein content had no effect.     

Amino acid profiles of rumen undegradable protein: a comparison between forages including cereal straws and alfalfa and their respective total mixed rations

Optimizing the amino acid (AA) profile of rumen undegradable protein (RUP) can positively affect the amount of milk protein. This study was conducted to improve knowledge regarding the AA profile of rumen undegradable protein from corn stover, rice straw and alfalfa hay as well as the total mixed ratio diets (TMR) based on one of them as forage source [forage‐to‐concentrate ratio of 45:55 (30% of corn stover (CS), 30% of rice straw (RS), 23% of alfalfa hay (AH) and dry matter basis)]. The other ingredients in the three TMR diets were similar. The RUP of all the forages and diets was estimated by incubation for 16 hr in the rumen of three ruminally cannulated lactating cows. All residues were corrected for microbial colonization, which was necessary in determining the AA composition of RUP from feed samples using in situ method. Compared with their original AA composition, the AA pattern of forages and forage‐based diets changed drastically after rumen exposure. In addition, the extent of ruminal degradation of analysed AA was not constant among the forages. The greatest individual AA degradability of alfalfa hay and corn stover was Pro, but was His of rice straw. A remarkable difference was observed between microbial attachment corrected and uncorrected AA profiles of RUP, except for alfalfa hay and His in the three forages and TMR diets. The ruminal AA degradability of cereal straws was altered compared with alfalfa hay but not for the TMR diets. In summary, the AA composition of forages and TMR‐based diets changed significantly after ruminal exposure, indicating that the original AA profiles of the feed cannot represent its AA composition of RUP. The AA profile of RUP and ruminal AA degradability for corn stover and rice straw contributed to missing information in the field.     

干旱胁迫下外源油菜素内酯对玉米幼苗光合作用和D1蛋白的调控效应

为了揭示干旱胁迫下外源油菜素内酯对玉米幼苗光合作用的保护机制,采用溶液培养的方法,以驻玉309为试验材料,研究外源油菜素内酯(BR)预处理及20% PEG-6000模拟干旱胁迫后玉米幼苗的生长参数、叶绿素含量、光合参数、叶绿素荧光参数及D1蛋白含量的变化。结果表明,与干旱胁迫处理(PEG)相比,BR+PEG处理的玉米苗株高增加45.87%,根长增加20.56%,总干物质积累增加8.01%,叶片相对含水量提高4.50%,叶绿素a含量增加26.32%,光合参数(Pn、Gs、Ci、Tr)分别提高9.57%,38.23%,30.19%,28.12%,光合系统Ⅱ(ΦPSⅡ)活性提高了20.48%,最大光化学效率提高了0.66%,光合系统Ⅱ绝对电子传递速率(ETR(Ⅱ)和相对电子传递速率r ETR(Ⅱ))分别提高20.40%和31.02%;D1蛋白含量增加37.34%(P0.05)。说明在干旱胁迫条件下叶片喷施BR可以改善玉米幼苗的生长发育,减缓光合系统的损伤,促进D1蛋白质的稳定,从而提高玉米幼苗对干旱胁迫的适应性。     

极细链格孢激活蛋白对大豆光合特性、叶绿素荧光参数及产量的影响

为探讨激活蛋白对大豆生长、产量的影响,以大豆冀豆17为研究对象,利用光合仪与称重法测量了不同浓度极细链格孢激活蛋白(1,2,3,4,5,6μg/m L)处理后大豆的光合特性、叶绿素荧光参数及产量。结果表明,随着施用的极细链格孢激活蛋白浓度的增加,大豆叶绿素含量、净光合速率、气孔导度、蒸腾速率、最大光化学量子效率(Fv/Fm)、有效量子效率(ΦPSⅡ)和光化学猝灭系数(q P)呈先上升后下降的趋势。施用1,2,3,4μg/m L浓度的极细链格孢激活蛋白不仅提高了大豆叶绿素含量,而且增加了大豆叶片的净光合速率、气孔导度、蒸腾速率,同时还能提高叶绿素荧光的最大光化学量子效率(Fv/Fm)、有效量子效率(ΦPSⅡ)和光化学猝灭系数(q P)。其中以3,4μg/m L浓度的处理效果最好。施用更高浓度的激活蛋白(5,6μg/m L),上述光合特性与叶绿素荧光促进效果下降或者消失。施用中浓度激活蛋白(3,4μg/m L)大豆产量增加了11.21%~14.76%。结果表明,喷洒合适浓度的极细链格孢激活蛋白是一种促进大豆增产的有效措施。